--- a/engine/sqlite/src/pager.cpp Wed May 26 10:44:32 2010 +0100
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,5142 +0,0 @@
-/*
-** 2001 September 15
-**
-** The author disclaims copyright to this source code. In place of
-** a legal notice, here is a blessing:
-**
-** May you do good and not evil.
-** May you find forgiveness for yourself and forgive others.
-** May you share freely, never taking more than you give.
-**
-*************************************************************************
-** This is the implementation of the page cache subsystem or "pager".
-**
-** The pager is used to access a database disk file. It implements
-** atomic commit and rollback through the use of a journal file that
-** is separate from the database file. The pager also implements file
-** locking to prevent two processes from writing the same database
-** file simultaneously, or one process from reading the database while
-** another is writing.
-**
-** @(#) $Id: pager.cpp 1282 2008-11-13 09:31:33Z LarsPson $
-*/
-#ifndef SQLITE_OMIT_DISKIO
-#include "sqliteInt.h"
-#include <assert.h>
-#include <string.h>
-
-/*
-** Macros for troubleshooting. Normally turned off
-*/
-#if 0
-#define sqlite3DebugPrintf printf
-#define PAGERTRACE1(X) sqlite3DebugPrintf(X)
-#define PAGERTRACE2(X,Y) sqlite3DebugPrintf(X,Y)
-#define PAGERTRACE3(X,Y,Z) sqlite3DebugPrintf(X,Y,Z)
-#define PAGERTRACE4(X,Y,Z,W) sqlite3DebugPrintf(X,Y,Z,W)
-#define PAGERTRACE5(X,Y,Z,W,V) sqlite3DebugPrintf(X,Y,Z,W,V)
-#else
-#define PAGERTRACE1(X)
-#define PAGERTRACE2(X,Y)
-#define PAGERTRACE3(X,Y,Z)
-#define PAGERTRACE4(X,Y,Z,W)
-#define PAGERTRACE5(X,Y,Z,W,V)
-#endif
-
-/*
-** The following two macros are used within the PAGERTRACEX() macros above
-** to print out file-descriptors.
-**
-** PAGERID() takes a pointer to a Pager struct as its argument. The
-** associated file-descriptor is returned. FILEHANDLEID() takes an sqlite3_file
-** struct as its argument.
-*/
-#define PAGERID(p) ((int)(p->fd))
-#define FILEHANDLEID(fd) ((int)fd)
-
-/*
-** The page cache as a whole is always in one of the following
-** states:
-**
-** PAGER_UNLOCK The page cache is not currently reading or
-** writing the database file. There is no
-** data held in memory. This is the initial
-** state.
-**
-** PAGER_SHARED The page cache is reading the database.
-** Writing is not permitted. There can be
-** multiple readers accessing the same database
-** file at the same time.
-**
-** PAGER_RESERVED This process has reserved the database for writing
-** but has not yet made any changes. Only one process
-** at a time can reserve the database. The original
-** database file has not been modified so other
-** processes may still be reading the on-disk
-** database file.
-**
-** PAGER_EXCLUSIVE The page cache is writing the database.
-** Access is exclusive. No other processes or
-** threads can be reading or writing while one
-** process is writing.
-**
-** PAGER_SYNCED The pager moves to this state from PAGER_EXCLUSIVE
-** after all dirty pages have been written to the
-** database file and the file has been synced to
-** disk. All that remains to do is to remove or
-** truncate the journal file and the transaction
-** will be committed.
-**
-** The page cache comes up in PAGER_UNLOCK. The first time a
-** sqlite3PagerGet() occurs, the state transitions to PAGER_SHARED.
-** After all pages have been released using sqlite_page_unref(),
-** the state transitions back to PAGER_UNLOCK. The first time
-** that sqlite3PagerWrite() is called, the state transitions to
-** PAGER_RESERVED. (Note that sqlite3PagerWrite() can only be
-** called on an outstanding page which means that the pager must
-** be in PAGER_SHARED before it transitions to PAGER_RESERVED.)
-** PAGER_RESERVED means that there is an open rollback journal.
-** The transition to PAGER_EXCLUSIVE occurs before any changes
-** are made to the database file, though writes to the rollback
-** journal occurs with just PAGER_RESERVED. After an sqlite3PagerRollback()
-** or sqlite3PagerCommitPhaseTwo(), the state can go back to PAGER_SHARED,
-** or it can stay at PAGER_EXCLUSIVE if we are in exclusive access mode.
-*/
-#define PAGER_UNLOCK 0
-#define PAGER_SHARED 1 /* same as SHARED_LOCK */
-#define PAGER_RESERVED 2 /* same as RESERVED_LOCK */
-#define PAGER_EXCLUSIVE 4 /* same as EXCLUSIVE_LOCK */
-#define PAGER_SYNCED 5
-
-/*
-** If the SQLITE_BUSY_RESERVED_LOCK macro is set to true at compile-time,
-** then failed attempts to get a reserved lock will invoke the busy callback.
-** This is off by default. To see why, consider the following scenario:
-**
-** Suppose thread A already has a shared lock and wants a reserved lock.
-** Thread B already has a reserved lock and wants an exclusive lock. If
-** both threads are using their busy callbacks, it might be a long time
-** be for one of the threads give up and allows the other to proceed.
-** But if the thread trying to get the reserved lock gives up quickly
-** (if it never invokes its busy callback) then the contention will be
-** resolved quickly.
-*/
-#ifndef SQLITE_BUSY_RESERVED_LOCK
-# define SQLITE_BUSY_RESERVED_LOCK 0
-#endif
-
-/*
-** This macro rounds values up so that if the value is an address it
-** is guaranteed to be an address that is aligned to an 8-byte boundary.
-*/
-#define FORCE_ALIGNMENT(X) (((X)+7)&~7)
-
-typedef struct PgHdr PgHdr;
-
-/*
-** Each pager stores all currently unreferenced pages in a list sorted
-** in least-recently-used (LRU) order (i.e. the first item on the list has
-** not been referenced in a long time, the last item has been recently
-** used). An instance of this structure is included as part of each
-** pager structure for this purpose (variable Pager.lru).
-**
-** Additionally, if memory-management is enabled, all unreferenced pages
-** are stored in a global LRU list (global variable sqlite3LruPageList).
-**
-** In both cases, the PagerLruList.pFirstSynced variable points to
-** the first page in the corresponding list that does not require an
-** fsync() operation before its memory can be reclaimed. If no such
-** page exists, PagerLruList.pFirstSynced is set to NULL.
-*/
-typedef struct PagerLruList PagerLruList;
-struct PagerLruList {
- PgHdr *pFirst; /* First page in LRU list */
- PgHdr *pLast; /* Last page in LRU list (the most recently used) */
- PgHdr *pFirstSynced; /* First page in list with PgHdr.needSync==0 */
-};
-
-/*
-** The following structure contains the next and previous pointers used
-** to link a PgHdr structure into a PagerLruList linked list.
-*/
-typedef struct PagerLruLink PagerLruLink;
-struct PagerLruLink {
- PgHdr *pNext;
- PgHdr *pPrev;
-};
-
-/*
-** Each in-memory image of a page begins with the following header.
-** This header is only visible to this pager module. The client
-** code that calls pager sees only the data that follows the header.
-**
-** Client code should call sqlite3PagerWrite() on a page prior to making
-** any modifications to that page. The first time sqlite3PagerWrite()
-** is called, the original page contents are written into the rollback
-** journal and PgHdr.inJournal and PgHdr.needSync are set. Later, once
-** the journal page has made it onto the disk surface, PgHdr.needSync
-** is cleared. The modified page cannot be written back into the original
-** database file until the journal pages has been synced to disk and the
-** PgHdr.needSync has been cleared.
-**
-** The PgHdr.dirty flag is set when sqlite3PagerWrite() is called and
-** is cleared again when the page content is written back to the original
-** database file.
-**
-** Details of important structure elements:
-**
-** needSync
-**
-** If this is true, this means that it is not safe to write the page
-** content to the database because the original content needed
-** for rollback has not by synced to the main rollback journal.
-** The original content may have been written to the rollback journal
-** but it has not yet been synced. So we cannot write to the database
-** file because power failure might cause the page in the journal file
-** to never reach the disk. It is as if the write to the journal file
-** does not occur until the journal file is synced.
-**
-** This flag is false if the page content exactly matches what
-** currently exists in the database file. The needSync flag is also
-** false if the original content has been written to the main rollback
-** journal and synced. If the page represents a new page that has
-** been added onto the end of the database during the current
-** transaction, the needSync flag is true until the original database
-** size in the journal header has been synced to disk.
-**
-** inJournal
-**
-** This is true if the original page has been written into the main
-** rollback journal. This is always false for new pages added to
-** the end of the database file during the current transaction.
-** And this flag says nothing about whether or not the journal
-** has been synced to disk. For pages that are in the original
-** database file, the following expression should always be true:
-**
-** inJournal = (pPager->aInJournal[(pgno-1)/8] & (1<<((pgno-1)%8))!=0
-**
-** The pPager->aInJournal[] array is only valid for the original
-** pages of the database, not new pages that are added to the end
-** of the database, so obviously the above expression cannot be
-** valid for new pages. For new pages inJournal is always 0.
-**
-** dirty
-**
-** When true, this means that the content of the page has been
-** modified and needs to be written back to the database file.
-** If false, it means that either the content of the page is
-** unchanged or else the content is unimportant and we do not
-** care whether or not it is preserved.
-**
-** alwaysRollback
-**
-** This means that the sqlite3PagerDontRollback() API should be
-** ignored for this page. The DontRollback() API attempts to say
-** that the content of the page on disk is unimportant (it is an
-** unused page on the freelist) so that it is unnecessary to
-** rollback changes to this page because the content of the page
-** can change without changing the meaning of the database. This
-** flag overrides any DontRollback() attempt. This flag is set
-** when a page that originally contained valid data is added to
-** the freelist. Later in the same transaction, this page might
-** be pulled from the freelist and reused for something different
-** and at that point the DontRollback() API will be called because
-** pages taken from the freelist do not need to be protected by
-** the rollback journal. But this flag says that the page was
-** not originally part of the freelist so that it still needs to
-** be rolled back in spite of any subsequent DontRollback() calls.
-**
-** needRead
-**
-** This flag means (when true) that the content of the page has
-** not yet been loaded from disk. The in-memory content is just
-** garbage. (Actually, we zero the content, but you should not
-** make any assumptions about the content nevertheless.) If the
-** content is needed in the future, it should be read from the
-** original database file.
-*/
-struct PgHdr {
- Pager *pPager; /* The pager to which this page belongs */
- Pgno pgno; /* The page number for this page */
- PgHdr *pNextHash, *pPrevHash; /* Hash collision chain for PgHdr.pgno */
- PagerLruLink free; /* Next and previous free pages */
- PgHdr *pNextAll; /* A list of all pages */
- u8 inJournal; /* TRUE if has been written to journal */
- u8 dirty; /* TRUE if we need to write back changes */
- u8 needSync; /* Sync journal before writing this page */
- u8 alwaysRollback; /* Disable DontRollback() for this page */
- u8 needRead; /* Read content if PagerWrite() is called */
- short int nRef; /* Number of users of this page */
- PgHdr *pDirty, *pPrevDirty; /* Dirty pages */
-#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
- PagerLruLink gfree; /* Global list of nRef==0 pages */
-#endif
-#ifdef SQLITE_CHECK_PAGES
- u32 pageHash;
-#endif
- void *pData; /* Page data */
- /* Pager.nExtra bytes of local data appended to this header */
-};
-
-/*
-** For an in-memory only database, some extra information is recorded about
-** each page so that changes can be rolled back. (Journal files are not
-** used for in-memory databases.) The following information is added to
-** the end of every EXTRA block for in-memory databases.
-**
-** This information could have been added directly to the PgHdr structure.
-** But then it would take up an extra 8 bytes of storage on every PgHdr
-** even for disk-based databases. Splitting it out saves 8 bytes. This
-** is only a savings of 0.8% but those percentages add up.
-*/
-typedef struct PgHistory PgHistory;
-struct PgHistory {
- u8 *pOrig; /* Original page text. Restore to this on a full rollback */
- u8 *pStmt; /* Text as it was at the beginning of the current statement */
- PgHdr *pNextStmt, *pPrevStmt; /* List of pages in the statement journal */
- u8 inStmt; /* TRUE if in the statement subjournal */
-};
-
-/*
-** A macro used for invoking the codec if there is one
-*/
-#ifdef SQLITE_HAS_CODEC
-# define CODEC1(P,D,N,X) if( P->xCodec!=0 ){ P->xCodec(P->pCodecArg,D,N,X); }
-# define CODEC2(P,D,N,X) ((char*)(P->xCodec!=0?P->xCodec(P->pCodecArg,D,N,X):D))
-#else
-# define CODEC1(P,D,N,X) /* NO-OP */
-# define CODEC2(P,D,N,X) ((char*)D)
-#endif
-
-/*
-** Convert a pointer to a PgHdr into a pointer to its data
-** and back again.
-*/
-#define PGHDR_TO_DATA(P) ((P)->pData)
-#define PGHDR_TO_EXTRA(G,P) ((void*)&((G)[1]))
-#define PGHDR_TO_HIST(P,PGR) \
- ((PgHistory*)&((char*)(&(P)[1]))[(PGR)->nExtra])
-
-/*
-** A open page cache is an instance of the following structure.
-**
-** Pager.errCode may be set to SQLITE_IOERR, SQLITE_CORRUPT, or
-** or SQLITE_FULL. Once one of the first three errors occurs, it persists
-** and is returned as the result of every major pager API call. The
-** SQLITE_FULL return code is slightly different. It persists only until the
-** next successful rollback is performed on the pager cache. Also,
-** SQLITE_FULL does not affect the sqlite3PagerGet() and sqlite3PagerLookup()
-** APIs, they may still be used successfully.
-*/
-struct Pager {
- sqlite3_vfs *pVfs; /* OS functions to use for IO */
- u8 journalOpen; /* True if journal file descriptors is valid */
- u8 journalStarted; /* True if header of journal is synced */
- u8 useJournal; /* Use a rollback journal on this file */
- u8 noReadlock; /* Do not bother to obtain readlocks */
- u8 stmtOpen; /* True if the statement subjournal is open */
- u8 stmtInUse; /* True we are in a statement subtransaction */
- u8 stmtAutoopen; /* Open stmt journal when main journal is opened*/
- u8 noSync; /* Do not sync the journal if true */
- u8 fullSync; /* Do extra syncs of the journal for robustness */
- u8 sync_flags; /* One of SYNC_NORMAL or SYNC_FULL */
- u8 state; /* PAGER_UNLOCK, _SHARED, _RESERVED, etc. */
- u8 tempFile; /* zFilename is a temporary file */
- u8 readOnly; /* True for a read-only database */
- u8 needSync; /* True if an fsync() is needed on the journal */
- u8 dirtyCache; /* True if cached pages have changed */
- u8 alwaysRollback; /* Disable DontRollback() for all pages */
- u8 memDb; /* True to inhibit all file I/O */
- u8 setMaster; /* True if a m-j name has been written to jrnl */
- u8 doNotSync; /* Boolean. While true, do not spill the cache */
- u8 exclusiveMode; /* Boolean. True if locking_mode==EXCLUSIVE */
- u8 changeCountDone; /* Set after incrementing the change-counter */
- u32 vfsFlags; /* Flags for sqlite3_vfs.xOpen() */
- int errCode; /* One of several kinds of errors */
- int dbSize; /* Number of pages in the file */
- int origDbSize; /* dbSize before the current change */
- int stmtSize; /* Size of database (in pages) at stmt_begin() */
- int nRec; /* Number of pages written to the journal */
- u32 cksumInit; /* Quasi-random value added to every checksum */
- int stmtNRec; /* Number of records in stmt subjournal */
- int nExtra; /* Add this many bytes to each in-memory page */
- int pageSize; /* Number of bytes in a page */
- int nPage; /* Total number of in-memory pages */
- int nRef; /* Number of in-memory pages with PgHdr.nRef>0 */
- int mxPage; /* Maximum number of pages to hold in cache */
- Pgno mxPgno; /* Maximum allowed size of the database */
- u8 *aInJournal; /* One bit for each page in the database file */
- u8 *aInStmt; /* One bit for each page in the database */
- char *zFilename; /* Name of the database file */
- char *zJournal; /* Name of the journal file */
- char *zDirectory; /* Directory hold database and journal files */
- char *zStmtJrnl; /* Name of the statement journal file */
- sqlite3_file *fd, *jfd; /* File descriptors for database and journal */
- sqlite3_file *stfd; /* File descriptor for the statement subjournal*/
- BusyHandler *pBusyHandler; /* Pointer to sqlite.busyHandler */
- PagerLruList lru; /* LRU list of free pages */
- PgHdr *pAll; /* List of all pages */
- PgHdr *pStmt; /* List of pages in the statement subjournal */
- PgHdr *pDirty; /* List of all dirty pages */
- i64 journalOff; /* Current byte offset in the journal file */
- i64 journalHdr; /* Byte offset to previous journal header */
- i64 stmtHdrOff; /* First journal header written this statement */
- i64 stmtCksum; /* cksumInit when statement was started */
- i64 stmtJSize; /* Size of journal at stmt_begin() */
- int sectorSize; /* Assumed sector size during rollback */
-#ifdef SQLITE_TEST
- int nHit, nMiss; /* Cache hits and missing */
- int nRead, nWrite; /* Database pages read/written */
-#endif
- void (*xDestructor)(DbPage*,int); /* Call this routine when freeing pages */
- void (*xReiniter)(DbPage*,int); /* Call this routine when reloading pages */
-#ifdef SQLITE_HAS_CODEC
- void *(*xCodec)(void*,void*,Pgno,int); /* Routine for en/decoding data */
- void *pCodecArg; /* First argument to xCodec() */
-#endif
- int nHash; /* Size of the pager hash table */
- PgHdr **aHash; /* Hash table to map page number to PgHdr */
-#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
- Pager *pNext; /* Doubly linked list of pagers on which */
- Pager *pPrev; /* sqlite3_release_memory() will work */
- int iInUseMM; /* Non-zero if unavailable to MM */
- int iInUseDB; /* Non-zero if in sqlite3_release_memory() */
-#endif
- char *pTmpSpace; /* Pager.pageSize bytes of space for tmp use */
- char dbFileVers[16]; /* Changes whenever database file changes */
-};
-
-/*
-** The following global variables hold counters used for
-** testing purposes only. These variables do not exist in
-** a non-testing build. These variables are not thread-safe.
-*/
-#ifdef SQLITE_TEST
-int sqlite3_pager_readdb_count = 0; /* Number of full pages read from DB */
-int sqlite3_pager_writedb_count = 0; /* Number of full pages written to DB */
-int sqlite3_pager_writej_count = 0; /* Number of pages written to journal */
-int sqlite3_pager_pgfree_count = 0; /* Number of cache pages freed */
-# define PAGER_INCR(v) v++
-#else
-# define PAGER_INCR(v)
-#endif
-
-/*
-** The following variable points to the head of a double-linked list
-** of all pagers that are eligible for page stealing by the
-** sqlite3_release_memory() interface. Access to this list is
-** protected by the SQLITE_MUTEX_STATIC_MEM2 mutex.
-*/
-#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
-static Pager *sqlite3PagerList = 0;
-static PagerLruList sqlite3LruPageList = {0, 0, 0};
-#endif
-
-
-/*
-** Journal files begin with the following magic string. The data
-** was obtained from /dev/random. It is used only as a sanity check.
-**
-** Since version 2.8.0, the journal format contains additional sanity
-** checking information. If the power fails while the journal is begin
-** written, semi-random garbage data might appear in the journal
-** file after power is restored. If an attempt is then made
-** to roll the journal back, the database could be corrupted. The additional
-** sanity checking data is an attempt to discover the garbage in the
-** journal and ignore it.
-**
-** The sanity checking information for the new journal format consists
-** of a 32-bit checksum on each page of data. The checksum covers both
-** the page number and the pPager->pageSize bytes of data for the page.
-** This cksum is initialized to a 32-bit random value that appears in the
-** journal file right after the header. The random initializer is important,
-** because garbage data that appears at the end of a journal is likely
-** data that was once in other files that have now been deleted. If the
-** garbage data came from an obsolete journal file, the checksums might
-** be correct. But by initializing the checksum to random value which
-** is different for every journal, we minimize that risk.
-*/
-static const unsigned char aJournalMagic[] = {
- 0xd9, 0xd5, 0x05, 0xf9, 0x20, 0xa1, 0x63, 0xd7,
-};
-
-/*
-** The size of the header and of each page in the journal is determined
-** by the following macros.
-*/
-#define JOURNAL_PG_SZ(pPager) ((pPager->pageSize) + 8)
-
-/*
-** The journal header size for this pager. In the future, this could be
-** set to some value read from the disk controller. The important
-** characteristic is that it is the same size as a disk sector.
-*/
-#define JOURNAL_HDR_SZ(pPager) (pPager->sectorSize)
-
-/*
-** The macro MEMDB is true if we are dealing with an in-memory database.
-** We do this as a macro so that if the SQLITE_OMIT_MEMORYDB macro is set,
-** the value of MEMDB will be a constant and the compiler will optimize
-** out code that would never execute.
-*/
-#ifdef SQLITE_OMIT_MEMORYDB
-# define MEMDB 0
-#else
-# define MEMDB pPager->memDb
-#endif
-
-/*
-** Page number PAGER_MJ_PGNO is never used in an SQLite database (it is
-** reserved for working around a windows/posix incompatibility). It is
-** used in the journal to signify that the remainder of the journal file
-** is devoted to storing a master journal name - there are no more pages to
-** roll back. See comments for function writeMasterJournal() for details.
-*/
-/* #define PAGER_MJ_PGNO(x) (PENDING_BYTE/((x)->pageSize)) */
-#define PAGER_MJ_PGNO(x) ((PENDING_BYTE/((x)->pageSize))+1)
-
-/*
-** The maximum legal page number is (2^31 - 1).
-*/
-#define PAGER_MAX_PGNO 2147483647
-
-/*
-** The pagerEnter() and pagerLeave() routines acquire and release
-** a mutex on each pager. The mutex is recursive.
-**
-** This is a special-purpose mutex. It only provides mutual exclusion
-** between the Btree and the Memory Management sqlite3_release_memory()
-** function. It does not prevent, for example, two Btrees from accessing
-** the same pager at the same time. Other general-purpose mutexes in
-** the btree layer handle that chore.
-*/
-#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
- static void pagerEnter(Pager *p){
- p->iInUseDB++;
- if( p->iInUseMM && p->iInUseDB==1 ){
- sqlite3_mutex *mutex;
- mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM2);
- p->iInUseDB = 0;
- sqlite3_mutex_enter(mutex);
- p->iInUseDB = 1;
- sqlite3_mutex_leave(mutex);
- }
- assert( p->iInUseMM==0 );
- }
- static void pagerLeave(Pager *p){
- p->iInUseDB--;
- assert( p->iInUseDB>=0 );
- }
-#else
-# define pagerEnter(X)
-# define pagerLeave(X)
-#endif
-
-/*
-** Enable reference count tracking (for debugging) here:
-*/
-#ifdef SQLITE_DEBUG
- int pager3_refinfo_enable = 0;
- static void pager_refinfo(PgHdr *p){
- static int cnt = 0;
- if( !pager3_refinfo_enable ) return;
- sqlite3DebugPrintf(
- "REFCNT: %4d addr=%p nRef=%-3d total=%d\n",
- p->pgno, PGHDR_TO_DATA(p), p->nRef, p->pPager->nRef
- );
- cnt++; /* Something to set a breakpoint on */
- }
-# define REFINFO(X) pager_refinfo(X)
-#else
-# define REFINFO(X)
-#endif
-
-/*
-** Add page pPg to the end of the linked list managed by structure
-** pList (pPg becomes the last entry in the list - the most recently
-** used). Argument pLink should point to either pPg->free or pPg->gfree,
-** depending on whether pPg is being added to the pager-specific or
-** global LRU list.
-*/
-static void listAdd(PagerLruList *pList, PagerLruLink *pLink, PgHdr *pPg){
- pLink->pNext = 0;
- pLink->pPrev = pList->pLast;
-
-#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
- assert(pLink==&pPg->free || pLink==&pPg->gfree);
- assert(pLink==&pPg->gfree || pList!=&sqlite3LruPageList);
-#endif
-
- if( pList->pLast ){
- int iOff = (char *)pLink - (char *)pPg;
- PagerLruLink *pLastLink = (PagerLruLink *)(&((u8 *)pList->pLast)[iOff]);
- pLastLink->pNext = pPg;
- }else{
- assert(!pList->pFirst);
- pList->pFirst = pPg;
- }
-
- pList->pLast = pPg;
- if( !pList->pFirstSynced && pPg->needSync==0 ){
- pList->pFirstSynced = pPg;
- }
-}
-
-/*
-** Remove pPg from the list managed by the structure pointed to by pList.
-**
-** Argument pLink should point to either pPg->free or pPg->gfree, depending
-** on whether pPg is being added to the pager-specific or global LRU list.
-*/
-static void listRemove(PagerLruList *pList, PagerLruLink *pLink, PgHdr *pPg){
- int iOff = (char *)pLink - (char *)pPg;
-
-#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
- assert(pLink==&pPg->free || pLink==&pPg->gfree);
- assert(pLink==&pPg->gfree || pList!=&sqlite3LruPageList);
-#endif
-
- if( pPg==pList->pFirst ){
- pList->pFirst = pLink->pNext;
- }
- if( pPg==pList->pLast ){
- pList->pLast = pLink->pPrev;
- }
- if( pLink->pPrev ){
- PagerLruLink *pPrevLink = (PagerLruLink *)(&((u8 *)pLink->pPrev)[iOff]);
- pPrevLink->pNext = pLink->pNext;
- }
- if( pLink->pNext ){
- PagerLruLink *pNextLink = (PagerLruLink *)(&((u8 *)pLink->pNext)[iOff]);
- pNextLink->pPrev = pLink->pPrev;
- }
- if( pPg==pList->pFirstSynced ){
- PgHdr *p = pLink->pNext;
- while( p && p->needSync ){
- PagerLruLink *pL = (PagerLruLink *)(&((u8 *)p)[iOff]);
- p = pL->pNext;
- }
- pList->pFirstSynced = p;
- }
-
- pLink->pNext = pLink->pPrev = 0;
-}
-
-/*
-** Add page pPg to the list of free pages for the pager. If
-** memory-management is enabled, also add the page to the global
-** list of free pages.
-*/
-static void lruListAdd(PgHdr *pPg){
- listAdd(&pPg->pPager->lru, &pPg->free, pPg);
-#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
- if( !pPg->pPager->memDb ){
- sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU));
- listAdd(&sqlite3LruPageList, &pPg->gfree, pPg);
- sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU));
- }
-#endif
-}
-
-/*
-** Remove page pPg from the list of free pages for the associated pager.
-** If memory-management is enabled, also remove pPg from the global list
-** of free pages.
-*/
-static void lruListRemove(PgHdr *pPg){
- listRemove(&pPg->pPager->lru, &pPg->free, pPg);
-#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
- if( !pPg->pPager->memDb ){
- sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU));
- listRemove(&sqlite3LruPageList, &pPg->gfree, pPg);
- sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU));
- }
-#endif
-}
-
-/*
-** This function is called just after the needSync flag has been cleared
-** from all pages managed by pPager (usually because the journal file
-** has just been synced). It updates the pPager->lru.pFirstSynced variable
-** and, if memory-management is enabled, the sqlite3LruPageList.pFirstSynced
-** variable also.
-*/
-static void lruListSetFirstSynced(Pager *pPager){
- pPager->lru.pFirstSynced = pPager->lru.pFirst;
-#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
- if( !pPager->memDb ){
- PgHdr *p;
- sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU));
- for(p=sqlite3LruPageList.pFirst; p && p->needSync; p=p->gfree.pNext);
- assert(p==pPager->lru.pFirstSynced || p==sqlite3LruPageList.pFirstSynced);
- sqlite3LruPageList.pFirstSynced = p;
- sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU));
- }
-#endif
-}
-
-/*
-** Return true if page *pPg has already been written to the statement
-** journal (or statement snapshot has been created, if *pPg is part
-** of an in-memory database).
-*/
-static int pageInStatement(PgHdr *pPg){
- Pager *pPager = pPg->pPager;
- if( MEMDB ){
- return PGHDR_TO_HIST(pPg, pPager)->inStmt;
- }else{
- Pgno pgno = pPg->pgno;
- u8 *a = pPager->aInStmt;
- return (a && (int)pgno<=pPager->stmtSize && (a[pgno/8] & (1<<(pgno&7))));
- }
-}
-
-/*
-** Change the size of the pager hash table to N. N must be a power
-** of two.
-*/
-static void pager_resize_hash_table(Pager *pPager, int N){
- PgHdr **aHash, *pPg;
- assert( N>0 && (N&(N-1))==0 );
- pagerLeave(pPager);
- sqlite3MallocBenignFailure((int)pPager->aHash);
- aHash = (PgHdr**)sqlite3MallocZero( sizeof(aHash[0])*N );
- pagerEnter(pPager);
- if( aHash==0 ){
- /* Failure to rehash is not an error. It is only a performance hit. */
- return;
- }
- sqlite3_free(pPager->aHash);
- pPager->nHash = N;
- pPager->aHash = aHash;
- for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
- int h;
- if( pPg->pgno==0 ){
- assert( pPg->pNextHash==0 && pPg->pPrevHash==0 );
- continue;
- }
- h = pPg->pgno & (N-1);
- pPg->pNextHash = aHash[h];
- if( aHash[h] ){
- aHash[h]->pPrevHash = pPg;
- }
- aHash[h] = pPg;
- pPg->pPrevHash = 0;
- }
-}
-
-/*
-** Read a 32-bit integer from the given file descriptor. Store the integer
-** that is read in *pRes. Return SQLITE_OK if everything worked, or an
-** error code is something goes wrong.
-**
-** All values are stored on disk as big-endian.
-*/
-static int read32bits(sqlite3_file *fd, i64 offset, u32 *pRes){
- unsigned char ac[4];
- int rc = sqlite3OsRead(fd, ac, sizeof(ac), offset);
- if( rc==SQLITE_OK ){
- *pRes = sqlite3Get4byte(ac);
- }
- return rc;
-}
-
-/*
-** Write a 32-bit integer into a string buffer in big-endian byte order.
-*/
-#define put32bits(A,B) sqlite3Put4byte((u8*)A,B)
-
-/*
-** Write a 32-bit integer into the given file descriptor. Return SQLITE_OK
-** on success or an error code is something goes wrong.
-*/
-static int write32bits(sqlite3_file *fd, i64 offset, u32 val){
- char ac[4];
- put32bits(ac, val);
- return sqlite3OsWrite(fd, ac, 4, offset);
-}
-
-/*
-** If file pFd is open, call sqlite3OsUnlock() on it.
-*/
-static int osUnlock(sqlite3_file *pFd, int eLock){
- if( !pFd->isOpen ){
- return SQLITE_OK;
- }
- return sqlite3OsUnlock(pFd, eLock);
-}
-
-/*
-** This function determines whether or not the atomic-write optimization
-** can be used with this pager. The optimization can be used if:
-**
-** (a) the value returned by OsDeviceCharacteristics() indicates that
-** a database page may be written atomically, and
-** (b) the value returned by OsSectorSize() is less than or equal
-** to the page size.
-**
-** If the optimization cannot be used, 0 is returned. If it can be used,
-** then the value returned is the size of the journal file when it
-** contains rollback data for exactly one page.
-*/
-#ifdef SQLITE_ENABLE_ATOMIC_WRITE
-static int jrnlBufferSize(Pager *pPager){
- int dc; /* Device characteristics */
- int nSector; /* Sector size */
- int nPage; /* Page size */
- sqlite3_file *fd = pPager->fd;
-
- if( fd->pMethods ){
- dc = sqlite3OsDeviceCharacteristics(fd);
- nSector = sqlite3OsSectorSize(fd);
- nPage = pPager->pageSize;
- }
-
- assert(SQLITE_IOCAP_ATOMIC512==(512>>8));
- assert(SQLITE_IOCAP_ATOMIC64K==(65536>>8));
-
- if( !fd->pMethods || (dc&(SQLITE_IOCAP_ATOMIC|(nPage>>8))&&nSector<=nPage) ){
- return JOURNAL_HDR_SZ(pPager) + JOURNAL_PG_SZ(pPager);
- }
- return 0;
-}
-#endif
-
-/*
-** This function should be called when an error occurs within the pager
-** code. The first argument is a pointer to the pager structure, the
-** second the error-code about to be returned by a pager API function.
-** The value returned is a copy of the second argument to this function.
-**
-** If the second argument is SQLITE_IOERR, SQLITE_CORRUPT, or SQLITE_FULL
-** the error becomes persistent. Until the persisten error is cleared,
-** subsequent API calls on this Pager will immediately return the same
-** error code.
-**
-** A persistent error indicates that the contents of the pager-cache
-** cannot be trusted. This state can be cleared by completely discarding
-** the contents of the pager-cache. If a transaction was active when
-** the persistent error occured, then the rollback journal may need
-** to be replayed.
-*/
-static void pager_unlock(Pager *pPager);
-static int pager_error(Pager *pPager, int rc){
- int rc2 = rc & 0xff;
- assert(
- pPager->errCode==SQLITE_FULL ||
- pPager->errCode==SQLITE_OK ||
- (pPager->errCode & 0xff)==SQLITE_IOERR
- );
- if(
- rc2==SQLITE_FULL ||
- rc2==SQLITE_IOERR ||
- rc2==SQLITE_CORRUPT
- ){
- pPager->errCode = rc;
- if( pPager->state==PAGER_UNLOCK && pPager->nRef==0 ){
- /* If the pager is already unlocked, call pager_unlock() now to
- ** clear the error state and ensure that the pager-cache is
- ** completely empty.
- */
- pager_unlock(pPager);
- }
- }
- return rc;
-}
-
-/*
-** If SQLITE_CHECK_PAGES is defined then we do some sanity checking
-** on the cache using a hash function. This is used for testing
-** and debugging only.
-*/
-#ifdef SQLITE_CHECK_PAGES
-/*
-** Return a 32-bit hash of the page data for pPage.
-*/
-static u32 pager_datahash(int nByte, unsigned char *pData){
- u32 hash = 0;
- int i;
- for(i=0; i<nByte; i++){
- hash = (hash*1039) + pData[i];
- }
- return hash;
-}
-static u32 pager_pagehash(PgHdr *pPage){
- return pager_datahash(pPage->pPager->pageSize,
- (unsigned char *)PGHDR_TO_DATA(pPage));
-}
-
-/*
-** The CHECK_PAGE macro takes a PgHdr* as an argument. If SQLITE_CHECK_PAGES
-** is defined, and NDEBUG is not defined, an assert() statement checks
-** that the page is either dirty or still matches the calculated page-hash.
-*/
-#define CHECK_PAGE(x) checkPage(x)
-static void checkPage(PgHdr *pPg){
- Pager *pPager = pPg->pPager;
- assert( !pPg->pageHash || pPager->errCode || MEMDB || pPg->dirty ||
- pPg->pageHash==pager_pagehash(pPg) );
-}
-
-#else
-#define pager_datahash(X,Y) 0
-#define pager_pagehash(X) 0
-#define CHECK_PAGE(x)
-#endif
-
-/*
-** When this is called the journal file for pager pPager must be open.
-** The master journal file name is read from the end of the file and
-** written into memory supplied by the caller.
-**
-** zMaster must point to a buffer of at least nMaster bytes allocated by
-** the caller. This should be sqlite3_vfs.mxPathname+1 (to ensure there is
-** enough space to write the master journal name). If the master journal
-** name in the journal is longer than nMaster bytes (including a
-** nul-terminator), then this is handled as if no master journal name
-** were present in the journal.
-**
-** If no master journal file name is present zMaster[0] is set to 0 and
-** SQLITE_OK returned.
-*/
-static int readMasterJournal(sqlite3_file *pJrnl, char *zMaster, int nMaster){
- int rc;
- u32 len;
- i64 szJ;
- u32 cksum;
- int i;
- unsigned char aMagic[8]; /* A buffer to hold the magic header */
-
- zMaster[0] = '\0';
-
- rc = sqlite3OsFileSize(pJrnl, &szJ);
- if( rc!=SQLITE_OK || szJ<16 ) return rc;
-
- rc = read32bits(pJrnl, szJ-16, &len);
- if( rc!=SQLITE_OK ) return rc;
-
- if( len>=nMaster ){
- return SQLITE_OK;
- }
-
- rc = read32bits(pJrnl, szJ-12, &cksum);
- if( rc!=SQLITE_OK ) return rc;
-
- rc = sqlite3OsRead(pJrnl, aMagic, 8, szJ-8);
- if( rc!=SQLITE_OK || memcmp(aMagic, aJournalMagic, 8) ) return rc;
-
- rc = sqlite3OsRead(pJrnl, zMaster, len, szJ-16-len);
- if( rc!=SQLITE_OK ){
- return rc;
- }
- zMaster[len] = '\0';
-
- /* See if the checksum matches the master journal name */
- for(i=0; i<len; i++){
- cksum -= zMaster[i];
- }
- if( cksum ){
- /* If the checksum doesn't add up, then one or more of the disk sectors
- ** containing the master journal filename is corrupted. This means
- ** definitely roll back, so just return SQLITE_OK and report a (nul)
- ** master-journal filename.
- */
- zMaster[0] = '\0';
- }
-
- return SQLITE_OK;
-}
-
-/*
-** Seek the journal file descriptor to the next sector boundary where a
-** journal header may be read or written. Pager.journalOff is updated with
-** the new seek offset.
-**
-** i.e for a sector size of 512:
-**
-** Input Offset Output Offset
-** ---------------------------------------
-** 0 0
-** 512 512
-** 100 512
-** 2000 2048
-**
-*/
-static void seekJournalHdr(Pager *pPager){
- i64 offset = 0;
- i64 c = pPager->journalOff;
- if( c ){
- offset = ((c-1)/JOURNAL_HDR_SZ(pPager) + 1) * JOURNAL_HDR_SZ(pPager);
- }
- assert( offset%JOURNAL_HDR_SZ(pPager)==0 );
- assert( offset>=c );
- assert( (offset-c)<JOURNAL_HDR_SZ(pPager) );
- pPager->journalOff = offset;
-}
-
-/*
-** The journal file must be open when this routine is called. A journal
-** header (JOURNAL_HDR_SZ bytes) is written into the journal file at the
-** current location.
-**
-** The format for the journal header is as follows:
-** - 8 bytes: Magic identifying journal format.
-** - 4 bytes: Number of records in journal, or -1 no-sync mode is on.
-** - 4 bytes: Random number used for page hash.
-** - 4 bytes: Initial database page count.
-** - 4 bytes: Sector size used by the process that wrote this journal.
-**
-** Followed by (JOURNAL_HDR_SZ - 24) bytes of unused space.
-*/
-static int writeJournalHdr(Pager *pPager){
- char zHeader[sizeof(aJournalMagic)+16];
- int rc;
-
- if( pPager->stmtHdrOff==0 ){
- pPager->stmtHdrOff = pPager->journalOff;
- }
-
- seekJournalHdr(pPager);
- pPager->journalHdr = pPager->journalOff;
-
- memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
-
- /*
- ** Write the nRec Field - the number of page records that follow this
- ** journal header. Normally, zero is written to this value at this time.
- ** After the records are added to the journal (and the journal synced,
- ** if in full-sync mode), the zero is overwritten with the true number
- ** of records (see syncJournal()).
- **
- ** A faster alternative is to write 0xFFFFFFFF to the nRec field. When
- ** reading the journal this value tells SQLite to assume that the
- ** rest of the journal file contains valid page records. This assumption
- ** is dangerous, as if a failure occured whilst writing to the journal
- ** file it may contain some garbage data. There are two scenarios
- ** where this risk can be ignored:
- **
- ** * When the pager is in no-sync mode. Corruption can follow a
- ** power failure in this case anyway.
- **
- ** * When the SQLITE_IOCAP_SAFE_APPEND flag is set. This guarantees
- ** that garbage data is never appended to the journal file.
- */
- assert(pPager->fd->pMethods||pPager->noSync);
- if( (pPager->noSync)
- || (sqlite3OsDeviceCharacteristics(pPager->fd)&SQLITE_IOCAP_SAFE_APPEND)
- ){
- put32bits(&zHeader[sizeof(aJournalMagic)], 0xffffffff);
- }else{
- put32bits(&zHeader[sizeof(aJournalMagic)], 0);
- }
-
- /* The random check-hash initialiser */
- sqlite3Randomness(sizeof(pPager->cksumInit), &pPager->cksumInit);
- put32bits(&zHeader[sizeof(aJournalMagic)+4], pPager->cksumInit);
- /* The initial database size */
- put32bits(&zHeader[sizeof(aJournalMagic)+8], pPager->dbSize);
- /* The assumed sector size for this process */
- put32bits(&zHeader[sizeof(aJournalMagic)+12], pPager->sectorSize);
- IOTRACE(("JHDR %p %lld %d\n", pPager, pPager->journalHdr, sizeof(zHeader)))
- rc = sqlite3OsWrite(pPager->jfd, zHeader, sizeof(zHeader),pPager->journalOff);
- pPager->journalOff += JOURNAL_HDR_SZ(pPager);
-
- /* The journal header has been written successfully. Seek the journal
- ** file descriptor to the end of the journal header sector.
- */
- if( rc==SQLITE_OK ){
- IOTRACE(("JTAIL %p %lld\n", pPager, pPager->journalOff-1))
- rc = sqlite3OsWrite(pPager->jfd, "\000", 1, pPager->journalOff-1);
- }
- return rc;
-}
-
-/*
-** The journal file must be open when this is called. A journal header file
-** (JOURNAL_HDR_SZ bytes) is read from the current location in the journal
-** file. See comments above function writeJournalHdr() for a description of
-** the journal header format.
-**
-** If the header is read successfully, *nRec is set to the number of
-** page records following this header and *dbSize is set to the size of the
-** database before the transaction began, in pages. Also, pPager->cksumInit
-** is set to the value read from the journal header. SQLITE_OK is returned
-** in this case.
-**
-** If the journal header file appears to be corrupted, SQLITE_DONE is
-** returned and *nRec and *dbSize are not set. If JOURNAL_HDR_SZ bytes
-** cannot be read from the journal file an error code is returned.
-*/
-static int readJournalHdr(
- Pager *pPager,
- i64 journalSize,
- u32 *pNRec,
- u32 *pDbSize
-){
- int rc;
- unsigned char aMagic[8]; /* A buffer to hold the magic header */
- i64 jrnlOff;
-
- seekJournalHdr(pPager);
- if( pPager->journalOff+JOURNAL_HDR_SZ(pPager) > journalSize ){
- return SQLITE_DONE;
- }
- jrnlOff = pPager->journalOff;
-
- rc = sqlite3OsRead(pPager->jfd, aMagic, sizeof(aMagic), jrnlOff);
- if( rc ) return rc;
- jrnlOff += sizeof(aMagic);
-
- if( memcmp(aMagic, aJournalMagic, sizeof(aMagic))!=0 ){
- return SQLITE_DONE;
- }
-
- rc = read32bits(pPager->jfd, jrnlOff, pNRec);
- if( rc ) return rc;
-
- rc = read32bits(pPager->jfd, jrnlOff+4, &pPager->cksumInit);
- if( rc ) return rc;
-
- rc = read32bits(pPager->jfd, jrnlOff+8, pDbSize);
- if( rc ) return rc;
-
- /* Update the assumed sector-size to match the value used by
- ** the process that created this journal. If this journal was
- ** created by a process other than this one, then this routine
- ** is being called from within pager_playback(). The local value
- ** of Pager.sectorSize is restored at the end of that routine.
- */
- rc = read32bits(pPager->jfd, jrnlOff+12, (u32 *)&pPager->sectorSize);
- if( rc ) return rc;
-
- pPager->journalOff += JOURNAL_HDR_SZ(pPager);
- return SQLITE_OK;
-}
-
-
-/*
-** Write the supplied master journal name into the journal file for pager
-** pPager at the current location. The master journal name must be the last
-** thing written to a journal file. If the pager is in full-sync mode, the
-** journal file descriptor is advanced to the next sector boundary before
-** anything is written. The format is:
-**
-** + 4 bytes: PAGER_MJ_PGNO.
-** + N bytes: length of master journal name.
-** + 4 bytes: N
-** + 4 bytes: Master journal name checksum.
-** + 8 bytes: aJournalMagic[].
-**
-** The master journal page checksum is the sum of the bytes in the master
-** journal name.
-**
-** If zMaster is a NULL pointer (occurs for a single database transaction),
-** this call is a no-op.
-*/
-static int writeMasterJournal(Pager *pPager, const char *zMaster){
- int rc;
- int len;
- int i;
- i64 jrnlOff;
- u32 cksum = 0;
- char zBuf[sizeof(aJournalMagic)+2*4];
-
- if( !zMaster || pPager->setMaster) return SQLITE_OK;
- pPager->setMaster = 1;
-
- len = strlen(zMaster);
- for(i=0; i<len; i++){
- cksum += zMaster[i];
- }
-
- /* If in full-sync mode, advance to the next disk sector before writing
- ** the master journal name. This is in case the previous page written to
- ** the journal has already been synced.
- */
- if( pPager->fullSync ){
- seekJournalHdr(pPager);
- }
- jrnlOff = pPager->journalOff;
- pPager->journalOff += (len+20);
-
- rc = write32bits(pPager->jfd, jrnlOff, PAGER_MJ_PGNO(pPager));
- if( rc!=SQLITE_OK ) return rc;
- jrnlOff += 4;
-
- rc = sqlite3OsWrite(pPager->jfd, zMaster, len, jrnlOff);
- if( rc!=SQLITE_OK ) return rc;
- jrnlOff += len;
-
- put32bits(zBuf, len);
- put32bits(&zBuf[4], cksum);
- memcpy(&zBuf[8], aJournalMagic, sizeof(aJournalMagic));
- rc = sqlite3OsWrite(pPager->jfd, zBuf, 8+sizeof(aJournalMagic), jrnlOff);
- pPager->needSync = !pPager->noSync;
- return rc;
-}
-
-/*
-** Add or remove a page from the list of all pages that are in the
-** statement journal.
-**
-** The Pager keeps a separate list of pages that are currently in
-** the statement journal. This helps the sqlite3PagerStmtCommit()
-** routine run MUCH faster for the common case where there are many
-** pages in memory but only a few are in the statement journal.
-*/
-static void page_add_to_stmt_list(PgHdr *pPg){
- Pager *pPager = pPg->pPager;
- PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
- assert( MEMDB );
- if( !pHist->inStmt ){
- assert( pHist->pPrevStmt==0 && pHist->pNextStmt==0 );
- if( pPager->pStmt ){
- PGHDR_TO_HIST(pPager->pStmt, pPager)->pPrevStmt = pPg;
- }
- pHist->pNextStmt = pPager->pStmt;
- pPager->pStmt = pPg;
- pHist->inStmt = 1;
- }
-}
-
-/*
-** Find a page in the hash table given its page number. Return
-** a pointer to the page or NULL if not found.
-*/
-static PgHdr *pager_lookup(Pager *pPager, Pgno pgno){
- PgHdr *p;
- if( pPager->aHash==0 ) return 0;
- p = pPager->aHash[pgno & (pPager->nHash-1)];
- while( p && p->pgno!=pgno ){
- p = p->pNextHash;
- }
- return p;
-}
-
-/*
-** Clear the in-memory cache. This routine
-** sets the state of the pager back to what it was when it was first
-** opened. Any outstanding pages are invalidated and subsequent attempts
-** to access those pages will likely result in a coredump.
-*/
-static void pager_reset(Pager *pPager){
- PgHdr *pPg, *pNext;
- if( pPager->errCode ) return;
- for(pPg=pPager->pAll; pPg; pPg=pNext){
- IOTRACE(("PGFREE %p %d\n", pPager, pPg->pgno));
- PAGER_INCR(sqlite3_pager_pgfree_count);
- pNext = pPg->pNextAll;
- lruListRemove(pPg);
- sqlite3_free(pPg);
- }
- assert(pPager->lru.pFirst==0);
- assert(pPager->lru.pFirstSynced==0);
- assert(pPager->lru.pLast==0);
- pPager->pStmt = 0;
- pPager->pAll = 0;
- pPager->pDirty = 0;
- pPager->nHash = 0;
- sqlite3_free(pPager->aHash);
- pPager->nPage = 0;
- pPager->aHash = 0;
- pPager->nRef = 0;
-}
-
-/*
-** Unlock the database file.
-**
-** If the pager is currently in error state, discard the contents of
-** the cache and reset the Pager structure internal state. If there is
-** an open journal-file, then the next time a shared-lock is obtained
-** on the pager file (by this or any other process), it will be
-** treated as a hot-journal and rolled back.
-*/
-static void pager_unlock(Pager *pPager){
- if( !pPager->exclusiveMode ){
- if( !MEMDB ){
- if( pPager->fd->isOpen ){
- osUnlock(pPager->fd, NO_LOCK);
- }
- pPager->dbSize = -1;
- IOTRACE(("UNLOCK %p\n", pPager))
-
- /* If Pager.errCode is set, the contents of the pager cache cannot be
- ** trusted. Now that the pager file is unlocked, the contents of the
- ** cache can be discarded and the error code safely cleared.
- */
- if( pPager->errCode ){
- pPager->errCode = SQLITE_OK;
- pager_reset(pPager);
- if( pPager->stmtOpen ){
- sqlite3OsClose(pPager->stfd);
- sqlite3_free(pPager->aInStmt);
- pPager->aInStmt = 0;
- }
- if( pPager->journalOpen ){
- sqlite3OsClose(pPager->jfd);
- pPager->journalOpen = 0;
- sqlite3_free(pPager->aInJournal);
- pPager->aInJournal = 0;
- }
- pPager->stmtOpen = 0;
- pPager->stmtInUse = 0;
- pPager->journalOff = 0;
- pPager->journalStarted = 0;
- pPager->stmtAutoopen = 0;
- pPager->origDbSize = 0;
- }
- }
-
- if( !MEMDB || pPager->errCode==SQLITE_OK ){
- pPager->state = PAGER_UNLOCK;
- pPager->changeCountDone = 0;
- }
- }
-}
-
-/*
-** Execute a rollback if a transaction is active and unlock the
-** database file. If the pager has already entered the error state,
-** do not attempt the rollback.
-*/
-static void pagerUnlockAndRollback(Pager *p){
- assert( p->state>=PAGER_RESERVED || p->journalOpen==0 );
- if( p->errCode==SQLITE_OK && p->state>=PAGER_RESERVED ){
- sqlite3PagerRollback(p);
- }
- pager_unlock(p);
- assert( p->errCode || !p->journalOpen || (p->exclusiveMode&&!p->journalOff) );
- assert( p->errCode || !p->stmtOpen || p->exclusiveMode );
-}
-
-/*
-** This routine ends a transaction. A transaction is ended by either
-** a COMMIT or a ROLLBACK.
-**
-** When this routine is called, the pager has the journal file open and
-** a RESERVED or EXCLUSIVE lock on the database. This routine will release
-** the database lock and acquires a SHARED lock in its place if that is
-** the appropriate thing to do. Release locks usually is appropriate,
-** unless we are in exclusive access mode or unless this is a
-** COMMIT AND BEGIN or ROLLBACK AND BEGIN operation.
-**
-** The journal file is either deleted or truncated.
-**
-** TODO: Consider keeping the journal file open for temporary databases.
-** This might give a performance improvement on windows where opening
-** a file is an expensive operation.
-*/
-static int pager_end_transaction(Pager *pPager){
- PgHdr *pPg;
- int rc = SQLITE_OK;
- int rc2 = SQLITE_OK;
- assert( !MEMDB );
- if( pPager->state<PAGER_RESERVED ){
- return SQLITE_OK;
- }
- sqlite3PagerStmtCommit(pPager);
- if( pPager->stmtOpen && !pPager->exclusiveMode ){
- sqlite3OsClose(pPager->stfd);
- pPager->stmtOpen = 0;
- }
- if( pPager->journalOpen ){
- if( pPager->exclusiveMode
- && (rc = sqlite3OsTruncate(pPager->jfd, 0))==SQLITE_OK ){;
- pPager->journalOff = 0;
- pPager->journalStarted = 0;
- }else{
- sqlite3OsClose(pPager->jfd);
- pPager->journalOpen = 0;
- if( rc==SQLITE_OK ){
- rc = sqlite3OsDelete(pPager->pVfs, pPager->zJournal, 0);
- }
- }
- sqlite3_free( pPager->aInJournal );
- pPager->aInJournal = 0;
- for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
- pPg->inJournal = 0;
- pPg->dirty = 0;
- pPg->needSync = 0;
- pPg->alwaysRollback = 0;
-#ifdef SQLITE_CHECK_PAGES
- pPg->pageHash = pager_pagehash(pPg);
-#endif
- }
- pPager->pDirty = 0;
- pPager->dirtyCache = 0;
- pPager->nRec = 0;
- }else{
- assert( pPager->aInJournal==0 );
- assert( pPager->dirtyCache==0 || pPager->useJournal==0 );
- }
-
- if( !pPager->exclusiveMode ){
- rc2 = osUnlock(pPager->fd, SHARED_LOCK);
- pPager->state = PAGER_SHARED;
- }else if( pPager->state==PAGER_SYNCED ){
- pPager->state = PAGER_EXCLUSIVE;
- }
- pPager->origDbSize = 0;
- pPager->setMaster = 0;
- pPager->needSync = 0;
- lruListSetFirstSynced(pPager);
- pPager->dbSize = -1;
-
- return (rc==SQLITE_OK?rc2:rc);
-}
-
-/*
-** Compute and return a checksum for the page of data.
-**
-** This is not a real checksum. It is really just the sum of the
-** random initial value and the page number. We experimented with
-** a checksum of the entire data, but that was found to be too slow.
-**
-** Note that the page number is stored at the beginning of data and
-** the checksum is stored at the end. This is important. If journal
-** corruption occurs due to a power failure, the most likely scenario
-** is that one end or the other of the record will be changed. It is
-** much less likely that the two ends of the journal record will be
-** correct and the middle be corrupt. Thus, this "checksum" scheme,
-** though fast and simple, catches the mostly likely kind of corruption.
-**
-** FIX ME: Consider adding every 200th (or so) byte of the data to the
-** checksum. That way if a single page spans 3 or more disk sectors and
-** only the middle sector is corrupt, we will still have a reasonable
-** chance of failing the checksum and thus detecting the problem.
-*/
-static u32 pager_cksum(Pager *pPager, const u8 *aData){
- u32 cksum = pPager->cksumInit;
- int i = pPager->pageSize-200;
- while( i>0 ){
- cksum += aData[i];
- i -= 200;
- }
- return cksum;
-}
-
-/* Forward declaration */
-static void makeClean(PgHdr*);
-
-/*
-** Read a single page from the journal file opened on file descriptor
-** jfd. Playback this one page.
-**
-** If useCksum==0 it means this journal does not use checksums. Checksums
-** are not used in statement journals because statement journals do not
-** need to survive power failures.
-*/
-static int pager_playback_one_page(
- Pager *pPager,
- sqlite3_file *jfd,
- i64 offset,
- int useCksum
-){
- int rc;
- PgHdr *pPg; /* An existing page in the cache */
- Pgno pgno; /* The page number of a page in journal */
- u32 cksum; /* Checksum used for sanity checking */
- u8 *aData = (u8 *)pPager->pTmpSpace; /* Temp storage for a page */
-
- /* useCksum should be true for the main journal and false for
- ** statement journals. Verify that this is always the case
- */
- assert( jfd == (useCksum ? pPager->jfd : pPager->stfd) );
- assert( aData );
-
- rc = read32bits(jfd, offset, &pgno);
- if( rc!=SQLITE_OK ) return rc;
- rc = sqlite3OsRead(jfd, aData, pPager->pageSize, offset+4);
- if( rc!=SQLITE_OK ) return rc;
- pPager->journalOff += pPager->pageSize + 4;
-
- /* Sanity checking on the page. This is more important that I originally
- ** thought. If a power failure occurs while the journal is being written,
- ** it could cause invalid data to be written into the journal. We need to
- ** detect this invalid data (with high probability) and ignore it.
- */
- if( pgno==0 || pgno==PAGER_MJ_PGNO(pPager) ){
- return SQLITE_DONE;
- }
- if( pgno>(unsigned)pPager->dbSize ){
- return SQLITE_OK;
- }
- if( useCksum ){
- rc = read32bits(jfd, offset+pPager->pageSize+4, &cksum);
- if( rc ) return rc;
- pPager->journalOff += 4;
- if( pager_cksum(pPager, aData)!=cksum ){
- return SQLITE_DONE;
- }
- }
-
- assert( pPager->state==PAGER_RESERVED || pPager->state>=PAGER_EXCLUSIVE );
-
- /* If the pager is in RESERVED state, then there must be a copy of this
- ** page in the pager cache. In this case just update the pager cache,
- ** not the database file. The page is left marked dirty in this case.
- **
- ** An exception to the above rule: If the database is in no-sync mode
- ** and a page is moved during an incremental vacuum then the page may
- ** not be in the pager cache. Later: if a malloc() or IO error occurs
- ** during a Movepage() call, then the page may not be in the cache
- ** either. So the condition described in the above paragraph is not
- ** assert()able.
- **
- ** If in EXCLUSIVE state, then we update the pager cache if it exists
- ** and the main file. The page is then marked not dirty.
- **
- ** Ticket #1171: The statement journal might contain page content that is
- ** different from the page content at the start of the transaction.
- ** This occurs when a page is changed prior to the start of a statement
- ** then changed again within the statement. When rolling back such a
- ** statement we must not write to the original database unless we know
- ** for certain that original page contents are synced into the main rollback
- ** journal. Otherwise, a power loss might leave modified data in the
- ** database file without an entry in the rollback journal that can
- ** restore the database to its original form. Two conditions must be
- ** met before writing to the database files. (1) the database must be
- ** locked. (2) we know that the original page content is fully synced
- ** in the main journal either because the page is not in cache or else
- ** the page is marked as needSync==0.
- */
- pPg = pager_lookup(pPager, pgno);
- PAGERTRACE4("PLAYBACK %d page %d hash(%08x)\n",
- PAGERID(pPager), pgno, pager_datahash(pPager->pageSize, aData));
- if( pPager->state>=PAGER_EXCLUSIVE && (pPg==0 || pPg->needSync==0) ){
- i64 offset = (pgno-1)*(i64)pPager->pageSize;
- rc = sqlite3OsWrite(pPager->fd, aData, pPager->pageSize, offset);
- if( pPg ){
- makeClean(pPg);
- }
- }
- if( pPg ){
- /* No page should ever be explicitly rolled back that is in use, except
- ** for page 1 which is held in use in order to keep the lock on the
- ** database active. However such a page may be rolled back as a result
- ** of an internal error resulting in an automatic call to
- ** sqlite3PagerRollback().
- */
- void *pData;
- /* assert( pPg->nRef==0 || pPg->pgno==1 ); */
- pData = PGHDR_TO_DATA(pPg);
- memcpy(pData, aData, pPager->pageSize);
- if( pPager->xReiniter ){
- pPager->xReiniter(pPg, pPager->pageSize);
- }
-#ifdef SQLITE_CHECK_PAGES
- pPg->pageHash = pager_pagehash(pPg);
-#endif
- /* If this was page 1, then restore the value of Pager.dbFileVers.
- ** Do this before any decoding. */
- if( pgno==1 ){
- memcpy(&pPager->dbFileVers, &((u8*)pData)[24],sizeof(pPager->dbFileVers));
- }
-
- /* Decode the page just read from disk */
- CODEC1(pPager, pData, pPg->pgno, 3);
- }
- return rc;
-}
-
-/*
-** Parameter zMaster is the name of a master journal file. A single journal
-** file that referred to the master journal file has just been rolled back.
-** This routine checks if it is possible to delete the master journal file,
-** and does so if it is.
-**
-** Argument zMaster may point to Pager.pTmpSpace. So that buffer is not
-** available for use within this function.
-**
-**
-** The master journal file contains the names of all child journals.
-** To tell if a master journal can be deleted, check to each of the
-** children. If all children are either missing or do not refer to
-** a different master journal, then this master journal can be deleted.
-*/
-static int pager_delmaster(Pager *pPager, const char *zMaster){
- sqlite3_vfs *pVfs = pPager->pVfs;
- int rc;
- int master_open = 0;
- sqlite3_file *pMaster;
- sqlite3_file *pJournal;
- char *zMasterJournal = 0; /* Contents of master journal file */
- i64 nMasterJournal; /* Size of master journal file */
-
- /* Open the master journal file exclusively in case some other process
- ** is running this routine also. Not that it makes too much difference.
- */
- pMaster = (sqlite3_file *)sqlite3_malloc(pVfs->szOsFile * 2);
- pJournal = (sqlite3_file *)(((u8 *)pMaster) + pVfs->szOsFile);
- if( !pMaster ){
- rc = SQLITE_NOMEM;
- }else{
- int flags = (SQLITE_OPEN_READONLY|SQLITE_OPEN_MASTER_JOURNAL);
- rc = sqlite3OsOpen(pVfs, zMaster, pMaster, flags, 0);
- }
- if( rc!=SQLITE_OK ) goto delmaster_out;
- master_open = 1;
-
- rc = sqlite3OsFileSize(pMaster, &nMasterJournal);
- if( rc!=SQLITE_OK ) goto delmaster_out;
-
- if( nMasterJournal>0 ){
- char *zJournal;
- char *zMasterPtr = 0;
- int nMasterPtr = pPager->pVfs->mxPathname+1;
-
- /* Load the entire master journal file into space obtained from
- ** sqlite3_malloc() and pointed to by zMasterJournal.
- */
- zMasterJournal = (char *)sqlite3_malloc(nMasterJournal + nMasterPtr);
- if( !zMasterJournal ){
- rc = SQLITE_NOMEM;
- goto delmaster_out;
- }
- zMasterPtr = &zMasterJournal[nMasterJournal];
- rc = sqlite3OsRead(pMaster, zMasterJournal, nMasterJournal, 0);
- if( rc!=SQLITE_OK ) goto delmaster_out;
-
- zJournal = zMasterJournal;
- while( (zJournal-zMasterJournal)<nMasterJournal ){
- if( sqlite3OsAccess(pVfs, zJournal, SQLITE_ACCESS_EXISTS) ){
- /* One of the journals pointed to by the master journal exists.
- ** Open it and check if it points at the master journal. If
- ** so, return without deleting the master journal file.
- */
- int c;
- int flags = (SQLITE_OPEN_READONLY|SQLITE_OPEN_MAIN_JOURNAL);
- rc = sqlite3OsOpen(pVfs, zJournal, pJournal, flags, 0);
- if( rc!=SQLITE_OK ){
- goto delmaster_out;
- }
-
- rc = readMasterJournal(pJournal, zMasterPtr, nMasterPtr);
- sqlite3OsClose(pJournal);
- if( rc!=SQLITE_OK ){
- goto delmaster_out;
- }
-
- c = zMasterPtr[0]!=0 && strcmp(zMasterPtr, zMaster)==0;
- if( c ){
- /* We have a match. Do not delete the master journal file. */
- goto delmaster_out;
- }
- }
- zJournal += (strlen(zJournal)+1);
- }
- }
-
- rc = sqlite3OsDelete(pVfs, zMaster, 0);
-
-delmaster_out:
- if( zMasterJournal ){
- sqlite3_free(zMasterJournal);
- }
- if( master_open ){
- sqlite3OsClose(pMaster);
- }
- sqlite3_free(pMaster);
- return rc;
-}
-
-
-static void pager_truncate_cache(Pager *pPager);
-
-/*
-** Truncate the main file of the given pager to the number of pages
-** indicated. Also truncate the cached representation of the file.
-**
-** Might might be the case that the file on disk is smaller than nPage.
-** This can happen, for example, if we are in the middle of a transaction
-** which has extended the file size and the new pages are still all held
-** in cache, then an INSERT or UPDATE does a statement rollback. Some
-** operating system implementations can get confused if you try to
-** truncate a file to some size that is larger than it currently is,
-** so detect this case and do not do the truncation.
-*/
-static int pager_truncate(Pager *pPager, int nPage){
- int rc = SQLITE_OK;
- if( pPager->state>=PAGER_EXCLUSIVE && pPager->fd->isOpen ){
- i64 currentSize, newSize;
- rc = sqlite3OsFileSize(pPager->fd, ¤tSize);
- newSize = pPager->pageSize*(i64)nPage;
- if( rc==SQLITE_OK && currentSize>newSize ){
- rc = sqlite3OsTruncate(pPager->fd, newSize);
- }
- }
- if( rc==SQLITE_OK ){
- pPager->dbSize = nPage;
- pager_truncate_cache(pPager);
- }
- return rc;
-}
-
-/*
-** Set the sectorSize for the given pager.
-**
-** The sector size is the larger of the sector size reported
-** by sqlite3OsSectorSize() and the pageSize.
-*/
-static void setSectorSize(Pager *pPager){
- assert(pPager->fd->pMethods||pPager->tempFile);
- if( !pPager->tempFile ){
- /* Sector size doesn't matter for temporary files. Also, the file
- ** may not have been opened yet, in whcih case the OsSectorSize()
- ** call will segfault.
- */
- pPager->sectorSize = sqlite3OsSectorSize(pPager->fd);
- }
- if( pPager->sectorSize<pPager->pageSize ){
- pPager->sectorSize = pPager->pageSize;
- }
-}
-
-/*
-** Playback the journal and thus restore the database file to
-** the state it was in before we started making changes.
-**
-** The journal file format is as follows:
-**
-** (1) 8 byte prefix. A copy of aJournalMagic[].
-** (2) 4 byte big-endian integer which is the number of valid page records
-** in the journal. If this value is 0xffffffff, then compute the
-** number of page records from the journal size.
-** (3) 4 byte big-endian integer which is the initial value for the
-** sanity checksum.
-** (4) 4 byte integer which is the number of pages to truncate the
-** database to during a rollback.
-** (5) 4 byte integer which is the number of bytes in the master journal
-** name. The value may be zero (indicate that there is no master
-** journal.)
-** (6) N bytes of the master journal name. The name will be nul-terminated
-** and might be shorter than the value read from (5). If the first byte
-** of the name is \000 then there is no master journal. The master
-** journal name is stored in UTF-8.
-** (7) Zero or more pages instances, each as follows:
-** + 4 byte page number.
-** + pPager->pageSize bytes of data.
-** + 4 byte checksum
-**
-** When we speak of the journal header, we mean the first 6 items above.
-** Each entry in the journal is an instance of the 7th item.
-**
-** Call the value from the second bullet "nRec". nRec is the number of
-** valid page entries in the journal. In most cases, you can compute the
-** value of nRec from the size of the journal file. But if a power
-** failure occurred while the journal was being written, it could be the
-** case that the size of the journal file had already been increased but
-** the extra entries had not yet made it safely to disk. In such a case,
-** the value of nRec computed from the file size would be too large. For
-** that reason, we always use the nRec value in the header.
-**
-** If the nRec value is 0xffffffff it means that nRec should be computed
-** from the file size. This value is used when the user selects the
-** no-sync option for the journal. A power failure could lead to corruption
-** in this case. But for things like temporary table (which will be
-** deleted when the power is restored) we don't care.
-**
-** If the file opened as the journal file is not a well-formed
-** journal file then all pages up to the first corrupted page are rolled
-** back (or no pages if the journal header is corrupted). The journal file
-** is then deleted and SQLITE_OK returned, just as if no corruption had
-** been encountered.
-**
-** If an I/O or malloc() error occurs, the journal-file is not deleted
-** and an error code is returned.
-*/
-static int pager_playback(Pager *pPager, int isHot){
- sqlite3_vfs *pVfs = pPager->pVfs;
- i64 szJ; /* Size of the journal file in bytes */
- u32 nRec; /* Number of Records in the journal */
- int i; /* Loop counter */
- Pgno mxPg = 0; /* Size of the original file in pages */
- int rc; /* Result code of a subroutine */
- char *zMaster = 0; /* Name of master journal file if any */
-
- /* Figure out how many records are in the journal. Abort early if
- ** the journal is empty.
- */
- assert( pPager->journalOpen );
- rc = sqlite3OsFileSize(pPager->jfd, &szJ);
- if( rc!=SQLITE_OK || szJ==0 ){
- goto end_playback;
- }
-
- /* Read the master journal name from the journal, if it is present.
- ** If a master journal file name is specified, but the file is not
- ** present on disk, then the journal is not hot and does not need to be
- ** played back.
- */
- zMaster = pPager->pTmpSpace;
- rc = readMasterJournal(pPager->jfd, zMaster, pPager->pVfs->mxPathname+1);
- assert( rc!=SQLITE_DONE );
- if( rc!=SQLITE_OK
- || (zMaster[0] && !sqlite3OsAccess(pVfs, zMaster, SQLITE_ACCESS_EXISTS))
- ){
- zMaster = 0;
- if( rc==SQLITE_DONE ) rc = SQLITE_OK;
- goto end_playback;
- }
- pPager->journalOff = 0;
- zMaster = 0;
-
- /* This loop terminates either when the readJournalHdr() call returns
- ** SQLITE_DONE or an IO error occurs. */
- while( 1 ){
-
- /* Read the next journal header from the journal file. If there are
- ** not enough bytes left in the journal file for a complete header, or
- ** it is corrupted, then a process must of failed while writing it.
- ** This indicates nothing more needs to be rolled back.
- */
- rc = readJournalHdr(pPager, szJ, &nRec, &mxPg);
- if( rc!=SQLITE_OK ){
- if( rc==SQLITE_DONE ){
- rc = SQLITE_OK;
- }
- goto end_playback;
- }
-
- /* If nRec is 0xffffffff, then this journal was created by a process
- ** working in no-sync mode. This means that the rest of the journal
- ** file consists of pages, there are no more journal headers. Compute
- ** the value of nRec based on this assumption.
- */
- if( nRec==0xffffffff ){
- assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) );
- nRec = (szJ - JOURNAL_HDR_SZ(pPager))/JOURNAL_PG_SZ(pPager);
- }
-
- /* If nRec is 0 and this rollback is of a transaction created by this
- ** process and if this is the final header in the journal, then it means
- ** that this part of the journal was being filled but has not yet been
- ** synced to disk. Compute the number of pages based on the remaining
- ** size of the file.
- **
- ** The third term of the test was added to fix ticket #2565.
- */
- if( nRec==0 && !isHot &&
- pPager->journalHdr+JOURNAL_HDR_SZ(pPager)==pPager->journalOff ){
- nRec = (szJ - pPager->journalOff) / JOURNAL_PG_SZ(pPager);
- }
-
- /* If this is the first header read from the journal, truncate the
- ** database file back to its original size.
- */
- if( pPager->journalOff==JOURNAL_HDR_SZ(pPager) ){
- rc = pager_truncate(pPager, mxPg);
- if( rc!=SQLITE_OK ){
- goto end_playback;
- }
- }
-
- /* Copy original pages out of the journal and back into the database file.
- */
- for(i=0; i<nRec; i++){
- rc = pager_playback_one_page(pPager, pPager->jfd, pPager->journalOff, 1);
- if( rc!=SQLITE_OK ){
- if( rc==SQLITE_DONE ){
- rc = SQLITE_OK;
- pPager->journalOff = szJ;
- break;
- }else{
- goto end_playback;
- }
- }
- }
- }
- /*NOTREACHED*/
- assert( 0 );
-
-end_playback:
- if( rc==SQLITE_OK ){
- zMaster = pPager->pTmpSpace;
- rc = readMasterJournal(pPager->jfd, zMaster, pPager->pVfs->mxPathname+1);
- }
- if( rc==SQLITE_OK ){
- rc = pager_end_transaction(pPager);
- }
- if( rc==SQLITE_OK && zMaster[0] ){
- /* If there was a master journal and this routine will return success,
- ** see if it is possible to delete the master journal.
- */
- rc = pager_delmaster(pPager, zMaster);
- }
-
- /* The Pager.sectorSize variable may have been updated while rolling
- ** back a journal created by a process with a different sector size
- ** value. Reset it to the correct value for this process.
- */
- setSectorSize(pPager);
- return rc;
-}
-
-/*
-** Playback the statement journal.
-**
-** This is similar to playing back the transaction journal but with
-** a few extra twists.
-**
-** (1) The number of pages in the database file at the start of
-** the statement is stored in pPager->stmtSize, not in the
-** journal file itself.
-**
-** (2) In addition to playing back the statement journal, also
-** playback all pages of the transaction journal beginning
-** at offset pPager->stmtJSize.
-*/
-static int pager_stmt_playback(Pager *pPager){
- i64 szJ; /* Size of the full journal */
- i64 hdrOff;
- int nRec; /* Number of Records */
- int i; /* Loop counter */
- int rc;
-
- szJ = pPager->journalOff;
-#ifndef NDEBUG
- {
- i64 os_szJ;
- rc = sqlite3OsFileSize(pPager->jfd, &os_szJ);
- if( rc!=SQLITE_OK ) return rc;
- assert( szJ==os_szJ );
- }
-#endif
-
- /* Set hdrOff to be the offset just after the end of the last journal
- ** page written before the first journal-header for this statement
- ** transaction was written, or the end of the file if no journal
- ** header was written.
- */
- hdrOff = pPager->stmtHdrOff;
- assert( pPager->fullSync || !hdrOff );
- if( !hdrOff ){
- hdrOff = szJ;
- }
-
- /* Truncate the database back to its original size.
- */
- rc = pager_truncate(pPager, pPager->stmtSize);
- assert( pPager->state>=PAGER_SHARED );
-
- /* Figure out how many records are in the statement journal.
- */
- assert( pPager->stmtInUse && pPager->journalOpen );
- nRec = pPager->stmtNRec;
-
- /* Copy original pages out of the statement journal and back into the
- ** database file. Note that the statement journal omits checksums from
- ** each record since power-failure recovery is not important to statement
- ** journals.
- */
- for(i=0; i<nRec; i++){
- i64 offset = i*(4+pPager->pageSize);
- rc = pager_playback_one_page(pPager, pPager->stfd, offset, 0);
- assert( rc!=SQLITE_DONE );
- if( rc!=SQLITE_OK ) goto end_stmt_playback;
- }
-
- /* Now roll some pages back from the transaction journal. Pager.stmtJSize
- ** was the size of the journal file when this statement was started, so
- ** everything after that needs to be rolled back, either into the
- ** database, the memory cache, or both.
- **
- ** If it is not zero, then Pager.stmtHdrOff is the offset to the start
- ** of the first journal header written during this statement transaction.
- */
- pPager->journalOff = pPager->stmtJSize;
- pPager->cksumInit = pPager->stmtCksum;
- while( pPager->journalOff < hdrOff ){
- rc = pager_playback_one_page(pPager, pPager->jfd, pPager->journalOff, 1);
- assert( rc!=SQLITE_DONE );
- if( rc!=SQLITE_OK ) goto end_stmt_playback;
- }
-
- while( pPager->journalOff < szJ ){
- u32 nJRec; /* Number of Journal Records */
- u32 dummy;
- rc = readJournalHdr(pPager, szJ, &nJRec, &dummy);
- if( rc!=SQLITE_OK ){
- assert( rc!=SQLITE_DONE );
- goto end_stmt_playback;
- }
- if( nJRec==0 ){
- nJRec = (szJ - pPager->journalOff) / (pPager->pageSize+8);
- }
- for(i=nJRec-1; i>=0 && pPager->journalOff < szJ; i--){
- rc = pager_playback_one_page(pPager, pPager->jfd, pPager->journalOff, 1);
- assert( rc!=SQLITE_DONE );
- if( rc!=SQLITE_OK ) goto end_stmt_playback;
- }
- }
-
- pPager->journalOff = szJ;
-
-end_stmt_playback:
- if( rc==SQLITE_OK) {
- pPager->journalOff = szJ;
- /* pager_reload_cache(pPager); */
- }
- return rc;
-}
-
-/*
-** Change the maximum number of in-memory pages that are allowed.
-*/
-void sqlite3PagerSetCachesize(Pager *pPager, int mxPage){
- if( mxPage>10 ){
- pPager->mxPage = mxPage;
- }else{
- pPager->mxPage = 10;
- }
-}
-
-/*
-** Adjust the robustness of the database to damage due to OS crashes
-** or power failures by changing the number of syncs()s when writing
-** the rollback journal. There are three levels:
-**
-** OFF sqlite3OsSync() is never called. This is the default
-** for temporary and transient files.
-**
-** NORMAL The journal is synced once before writes begin on the
-** database. This is normally adequate protection, but
-** it is theoretically possible, though very unlikely,
-** that an inopertune power failure could leave the journal
-** in a state which would cause damage to the database
-** when it is rolled back.
-**
-** FULL The journal is synced twice before writes begin on the
-** database (with some additional information - the nRec field
-** of the journal header - being written in between the two
-** syncs). If we assume that writing a
-** single disk sector is atomic, then this mode provides
-** assurance that the journal will not be corrupted to the
-** point of causing damage to the database during rollback.
-**
-** Numeric values associated with these states are OFF==1, NORMAL=2,
-** and FULL=3.
-*/
-#ifndef SQLITE_OMIT_PAGER_PRAGMAS
-void sqlite3PagerSetSafetyLevel(Pager *pPager, int level, int full_fsync){
- pPager->noSync = level==1 || pPager->tempFile;
- pPager->fullSync = level==3 && !pPager->tempFile;
- pPager->sync_flags = (full_fsync?SQLITE_SYNC_FULL:SQLITE_SYNC_NORMAL);
- if( pPager->noSync ) pPager->needSync = 0;
-}
-#endif
-
-/*
-** The following global variable is incremented whenever the library
-** attempts to open a temporary file. This information is used for
-** testing and analysis only.
-*/
-#ifdef SQLITE_TEST
-int sqlite3_opentemp_count = 0;
-#endif
-
-/*
-** Open a temporary file.
-**
-** Write the file descriptor into *fd. Return SQLITE_OK on success or some
-** other error code if we fail. The OS will automatically delete the temporary
-** file when it is closed.
-*/
-static int sqlite3PagerOpentemp(
- sqlite3_vfs *pVfs, /* The virtual file system layer */
- sqlite3_file *pFile, /* Write the file descriptor here */
- char *zFilename, /* Name of the file. Might be NULL */
- int vfsFlags /* Flags passed through to the VFS */
-){
- int rc;
- assert( zFilename!=0 );
-
-#ifdef SQLITE_TEST
- sqlite3_opentemp_count++; /* Used for testing and analysis only */
-#endif
-
- vfsFlags |= SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE |
- SQLITE_OPEN_EXCLUSIVE | SQLITE_OPEN_DELETEONCLOSE;
- rc = sqlite3OsOpen(pVfs, zFilename, pFile, vfsFlags, 0);
- assert( rc!=SQLITE_OK || pFile->pMethods );
- return rc;
-}
-
-
-//void fopenTest()
-//{
-// FILE *fp = fopen("c:\\data\\redfivelabs\\temp\\sqlite.log", "w+");
-// if (fp != NULL)
-// {
-// char tmp[256];
-// sprintf(tmp, "Hallo Welt");
-// fwrite(tmp, strlen(tmp), 1, fp);
-// fclose(fp);
-// }
-// return 191280;
-//}
-
-/*
-** Create a new page cache and put a pointer to the page cache in *ppPager.
-** The file to be cached need not exist. The file is not locked until
-** the first call to sqlite3PagerGet() and is only held open until the
-** last page is released using sqlite3PagerUnref().
-**
-** If zFilename is NULL then a randomly-named temporary file is created
-** and used as the file to be cached. The file will be deleted
-** automatically when it is closed.
-**
-** If zFilename is ":memory:" then all information is held in cache.
-** It is never written to disk. This can be used to implement an
-** in-memory database.
-*/
-int sqlite3PagerOpen(
- sqlite3_vfs *pVfs, /* The virtual file system to use */
- Pager **ppPager, /* Return the Pager structure here */
- const char *zFilename, /* Name of the database file to open */
- int nExtra, /* Extra bytes append to each in-memory page */
- int flags, /* flags controlling this file */
- int vfsFlags /* flags passed through to sqlite3_vfs.xOpen() */
-){
- u8 *pPtr;
- Pager *pPager = 0;
- int rc = SQLITE_OK;
- int i;
- int tempFile = 0;
- int memDb = 0;
- int readOnly = 0;
- int useJournal = (flags & PAGER_OMIT_JOURNAL)==0;
- int noReadlock = (flags & PAGER_NO_READLOCK)!=0;
- int journalFileSize = sqlite3JournalSize(pVfs);
- int nDefaultPage = SQLITE_DEFAULT_PAGE_SIZE;
- char *zPathname;
- int nPathname;
-
-
- /* The default return is a NULL pointer */
- *ppPager = 0;
-
- /* Compute the full pathname */
- nPathname = pVfs->mxPathname+1;
- zPathname = (char*)sqlite3_malloc(nPathname);
- if( zPathname==0 ){
- return SQLITE_NOMEM;
- }
- if( zFilename && zFilename[0] ){
-#ifndef SQLITE_OMIT_MEMORYDB
- if( strcmp(zFilename,":memory:")==0 ){
- memDb = 1;
- zPathname[0] = 0;
- }else
-#endif
- {
-
- rc = sqlite3OsFullPathname(pVfs, zFilename, nPathname, zPathname);
- }
- }else{
- rc = sqlite3OsGetTempname(pVfs, nPathname, zPathname);
- }
- if( rc!=SQLITE_OK ){
- sqlite3_free(zPathname);
- return rc;
- }
-
- nPathname = strlen(zPathname);
-
- /* Allocate memory for the pager structure */
- pPager = (Pager*)sqlite3MallocZero(
- sizeof(*pPager) + /* Pager structure */
- journalFileSize + /* The journal file structure */
- pVfs->szOsFile * 2 + /* The db and stmt journal files */
- 4*nPathname + 40 /* zFilename, zDirectory, zJournal, zStmtJrnl */
- );
- if( !pPager ){
- sqlite3_free(zPathname);
- return SQLITE_NOMEM;
- }
- pPtr = (u8 *)&pPager[1];
- pPager->vfsFlags = vfsFlags;
- pPager->fd = (sqlite3_file*)&pPtr[pVfs->szOsFile*0];
- pPager->stfd = (sqlite3_file*)&pPtr[pVfs->szOsFile*1];
- pPager->jfd = (sqlite3_file*)&pPtr[pVfs->szOsFile*2];
- pPager->zFilename = (char*)&pPtr[pVfs->szOsFile*2+journalFileSize];
- pPager->zDirectory = &pPager->zFilename[nPathname+1];
- pPager->zJournal = &pPager->zDirectory[nPathname+1];
- pPager->zStmtJrnl = &pPager->zJournal[nPathname+10];
- pPager->pVfs = pVfs;
- memcpy(pPager->zFilename, zPathname, nPathname+1);
- sqlite3_free(zPathname);
-
-
- /* Open the pager file.
- */
- if( zFilename && zFilename[0] && !memDb ){
- if( nPathname>(pVfs->mxPathname - sizeof("-journal")) ){
- rc = SQLITE_CANTOPEN;
- }else{
- int fout = 0;
-
- rc = winOpen(pVfs, pPager->zFilename, pPager->fd,
- pPager->vfsFlags, &fout);
- readOnly = (fout&SQLITE_OPEN_READONLY);
-
- /* If the file was successfully opened for read/write access,
- ** choose a default page size in case we have to create the
- ** database file. The default page size is the maximum of:
- **
- ** + SQLITE_DEFAULT_PAGE_SIZE,
- ** + The value returned by sqlite3OsSectorSize()
- ** + The largest page size that can be written atomically.
- */
- if( rc==SQLITE_OK && !readOnly ){
- int iSectorSize = sqlite3OsSectorSize(pPager->fd);
- if( nDefaultPage<iSectorSize ){
- nDefaultPage = iSectorSize;
- }
-#ifdef SQLITE_ENABLE_ATOMIC_WRITE
- {
- int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
- int ii;
- assert(SQLITE_IOCAP_ATOMIC512==(512>>8));
- assert(SQLITE_IOCAP_ATOMIC64K==(65536>>8));
- assert(SQLITE_MAX_DEFAULT_PAGE_SIZE<=65536);
- for(ii=nDefaultPage; ii<=SQLITE_MAX_DEFAULT_PAGE_SIZE; ii=ii*2){
- if( iDc&(SQLITE_IOCAP_ATOMIC|(ii>>8)) ) nDefaultPage = ii;
- }
- }
-#endif
- if( nDefaultPage>SQLITE_MAX_DEFAULT_PAGE_SIZE ){
- nDefaultPage = SQLITE_MAX_DEFAULT_PAGE_SIZE;
- }
- }
- }
- }else if( !memDb ){
- /* If a temporary file is requested, it is not opened immediately.
- ** In this case we accept the default page size and delay actually
- ** opening the file until the first call to OsWrite().
- */
- tempFile = 1;
- pPager->state = PAGER_EXCLUSIVE;
- }
-
- if( pPager && rc==SQLITE_OK ){
- pPager->pTmpSpace = (char *)sqlite3_malloc(nDefaultPage);
- }
-
- /* If an error occured in either of the blocks above.
- ** Free the Pager structure and close the file.
- ** Since the pager is not allocated there is no need to set
- ** any Pager.errMask variables.
- */
- if( !pPager || !pPager->pTmpSpace ){
- sqlite3OsClose(pPager->fd);
- sqlite3_free(pPager);
- return ((rc==SQLITE_OK)?SQLITE_NOMEM:rc);
- }
-
- PAGERTRACE3("OPEN %d %s\n", FILEHANDLEID(pPager->fd), pPager->zFilename);
- IOTRACE(("OPEN %p %s\n", pPager, pPager->zFilename))
-
- /* Fill in Pager.zDirectory[] */
- memcpy(pPager->zDirectory, pPager->zFilename, nPathname+1);
- for(i=strlen(pPager->zDirectory); i>0 && pPager->zDirectory[i-1]!='/'; i--){}
- if( i>0 ) pPager->zDirectory[i-1] = 0;
-
- /* Fill in Pager.zJournal[] and Pager.zStmtJrnl[] */
- memcpy(pPager->zJournal, pPager->zFilename, nPathname);
- memcpy(&pPager->zJournal[nPathname], "-journal", 9);
- memcpy(pPager->zStmtJrnl, pPager->zFilename, nPathname);
- memcpy(&pPager->zStmtJrnl[nPathname], "-stmtjrnl", 10);
-
- /* pPager->journalOpen = 0; */
- pPager->useJournal = useJournal && !memDb;
- pPager->noReadlock = noReadlock && readOnly;
- /* pPager->stmtOpen = 0; */
- /* pPager->stmtInUse = 0; */
- /* pPager->nRef = 0; */
- pPager->dbSize = memDb-1;
- pPager->pageSize = nDefaultPage;
- /* pPager->stmtSize = 0; */
- /* pPager->stmtJSize = 0; */
- /* pPager->nPage = 0; */
- pPager->mxPage = 100;
- pPager->mxPgno = SQLITE_MAX_PAGE_COUNT;
- /* pPager->state = PAGER_UNLOCK; */
- assert( pPager->state == (tempFile ? PAGER_EXCLUSIVE : PAGER_UNLOCK) );
- /* pPager->errMask = 0; */
- pPager->tempFile = tempFile;
- assert( tempFile==PAGER_LOCKINGMODE_NORMAL
- || tempFile==PAGER_LOCKINGMODE_EXCLUSIVE );
- assert( PAGER_LOCKINGMODE_EXCLUSIVE==1 );
- pPager->exclusiveMode = tempFile;
- pPager->memDb = memDb;
- pPager->readOnly = readOnly;
- /* pPager->needSync = 0; */
- pPager->noSync = pPager->tempFile || !useJournal;
- pPager->fullSync = (pPager->noSync?0:1);
- pPager->sync_flags = SQLITE_SYNC_NORMAL;
- /* pPager->pFirst = 0; */
- /* pPager->pFirstSynced = 0; */
- /* pPager->pLast = 0; */
- pPager->nExtra = FORCE_ALIGNMENT(nExtra);
- assert(pPager->fd->pMethods||memDb||tempFile);
- if( !memDb ){
- setSectorSize(pPager);
- }
- /* pPager->pBusyHandler = 0; */
- /* memset(pPager->aHash, 0, sizeof(pPager->aHash)); */
- *ppPager = pPager;
-#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
- pPager->iInUseMM = 0;
- pPager->iInUseDB = 0;
- if( !memDb ){
- sqlite3_mutex *mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM2);
- sqlite3_mutex_enter(mutex);
- pPager->pNext = sqlite3PagerList;
- if( sqlite3PagerList ){
- assert( sqlite3PagerList->pPrev==0 );
- sqlite3PagerList->pPrev = pPager;
- }
- pPager->pPrev = 0;
- sqlite3PagerList = pPager;
- sqlite3_mutex_leave(mutex);
- }
-#endif
- return SQLITE_OK;
-}
-
-/*
-** Set the busy handler function.
-*/
-void sqlite3PagerSetBusyhandler(Pager *pPager, BusyHandler *pBusyHandler){
- pPager->pBusyHandler = pBusyHandler;
-}
-
-/*
-** Set the destructor for this pager. If not NULL, the destructor is called
-** when the reference count on each page reaches zero. The destructor can
-** be used to clean up information in the extra segment appended to each page.
-**
-** The destructor is not called as a result sqlite3PagerClose().
-** Destructors are only called by sqlite3PagerUnref().
-*/
-void sqlite3PagerSetDestructor(Pager *pPager, void (*xDesc)(DbPage*,int)){
- pPager->xDestructor = xDesc;
-}
-
-/*
-** Set the reinitializer for this pager. If not NULL, the reinitializer
-** is called when the content of a page in cache is restored to its original
-** value as a result of a rollback. The callback gives higher-level code
-** an opportunity to restore the EXTRA section to agree with the restored
-** page data.
-*/
-void sqlite3PagerSetReiniter(Pager *pPager, void (*xReinit)(DbPage*,int)){
- pPager->xReiniter = xReinit;
-}
-
-/*
-** Set the page size to *pPageSize. If the suggest new page size is
-** inappropriate, then an alternative page size is set to that
-** value before returning.
-*/
-int sqlite3PagerSetPagesize(Pager *pPager, u16 *pPageSize){
- int rc = SQLITE_OK;
- u16 pageSize = *pPageSize;
- assert( pageSize==0 || (pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE) );
- if( pageSize && pageSize!=pPager->pageSize
- && !pPager->memDb && pPager->nRef==0
- ){
- char *pNew = (char *)sqlite3_malloc(pageSize);
- if( !pNew ){
- rc = SQLITE_NOMEM;
- }else{
- pagerEnter(pPager);
- pager_reset(pPager);
- pPager->pageSize = pageSize;
- setSectorSize(pPager);
- sqlite3_free(pPager->pTmpSpace);
- pPager->pTmpSpace = pNew;
- pagerLeave(pPager);
- }
- }
- *pPageSize = pPager->pageSize;
- return rc;
-}
-
-/*
-** Return a pointer to the "temporary page" buffer held internally
-** by the pager. This is a buffer that is big enough to hold the
-** entire content of a database page. This buffer is used internally
-** during rollback and will be overwritten whenever a rollback
-** occurs. But other modules are free to use it too, as long as
-** no rollbacks are happening.
-*/
-void *sqlite3PagerTempSpace(Pager *pPager){
- return pPager->pTmpSpace;
-}
-
-/*
-** Attempt to set the maximum database page count if mxPage is positive.
-** Make no changes if mxPage is zero or negative. And never reduce the
-** maximum page count below the current size of the database.
-**
-** Regardless of mxPage, return the current maximum page count.
-*/
-int sqlite3PagerMaxPageCount(Pager *pPager, int mxPage){
- if( mxPage>0 ){
- pPager->mxPgno = mxPage;
- }
- sqlite3PagerPagecount(pPager);
- return pPager->mxPgno;
-}
-
-/*
-** The following set of routines are used to disable the simulated
-** I/O error mechanism. These routines are used to avoid simulated
-** errors in places where we do not care about errors.
-**
-** Unless -DSQLITE_TEST=1 is used, these routines are all no-ops
-** and generate no code.
-*/
-#ifdef SQLITE_TEST
-extern int sqlite3_io_error_pending;
-extern int sqlite3_io_error_hit;
-static int saved_cnt;
-void disable_simulated_io_errors(void){
- saved_cnt = sqlite3_io_error_pending;
- sqlite3_io_error_pending = -1;
-}
-void enable_simulated_io_errors(void){
- sqlite3_io_error_pending = saved_cnt;
-}
-#else
-# define disable_simulated_io_errors()
-# define enable_simulated_io_errors()
-#endif
-
-/*
-** Read the first N bytes from the beginning of the file into memory
-** that pDest points to.
-**
-** No error checking is done. The rational for this is that this function
-** may be called even if the file does not exist or contain a header. In
-** these cases sqlite3OsRead() will return an error, to which the correct
-** response is to zero the memory at pDest and continue. A real IO error
-** will presumably recur and be picked up later (Todo: Think about this).
-*/
-int sqlite3PagerReadFileheader(Pager *pPager, int N, unsigned char *pDest){
- int rc = SQLITE_OK;
- memset(pDest, 0, N);
- assert(MEMDB||pPager->fd->pMethods||pPager->tempFile);
- if( pPager->fd->isOpen ){
- IOTRACE(("DBHDR %p 0 %d\n", pPager, N))
- rc = sqlite3OsRead(pPager->fd, pDest, N, 0);
- if( rc==SQLITE_IOERR_SHORT_READ ){
- rc = SQLITE_OK;
- }
- }
- return rc;
-}
-
-/*
-** Return the total number of pages in the disk file associated with
-** pPager.
-**
-** If the PENDING_BYTE lies on the page directly after the end of the
-** file, then consider this page part of the file too. For example, if
-** PENDING_BYTE is byte 4096 (the first byte of page 5) and the size of the
-** file is 4096 bytes, 5 is returned instead of 4.
-*/
-int sqlite3PagerPagecount(Pager *pPager){
- i64 n = 0;
- int rc;
- assert( pPager!=0 );
- if( pPager->errCode ){
- return 0;
- }
- if( pPager->dbSize>=0 ){
- n = pPager->dbSize;
- } else {
- assert(pPager->fd->pMethods||pPager->tempFile);
- if( (pPager->fd->isOpen)
- && (rc = sqlite3OsFileSize(pPager->fd, &n))!=SQLITE_OK ){
- pPager->nRef++;
- pager_error(pPager, rc);
- pPager->nRef--;
- return 0;
- }
- if( n>0 && n<pPager->pageSize ){
- n = 1;
- }else{
- n /= pPager->pageSize;
- }
- if( pPager->state!=PAGER_UNLOCK ){
- pPager->dbSize = n;
- }
- }
- if( n==(PENDING_BYTE/pPager->pageSize) ){
- n++;
- }
- if( n>pPager->mxPgno ){
- pPager->mxPgno = n;
- }
- return n;
-}
-
-
-#ifndef SQLITE_OMIT_MEMORYDB
-/*
-** Clear a PgHistory block
-*/
-static void clearHistory(PgHistory *pHist){
- sqlite3_free(pHist->pOrig);
- sqlite3_free(pHist->pStmt);
- pHist->pOrig = 0;
- pHist->pStmt = 0;
-}
-#else
-#define clearHistory(x)
-#endif
-
-/*
-** Forward declaration
-*/
-static int syncJournal(Pager*);
-
-/*
-** Unlink pPg from its hash chain. Also set the page number to 0 to indicate
-** that the page is not part of any hash chain. This is required because the
-** sqlite3PagerMovepage() routine can leave a page in the
-** pNextFree/pPrevFree list that is not a part of any hash-chain.
-*/
-static void unlinkHashChain(Pager *pPager, PgHdr *pPg){
- if( pPg->pgno==0 ){
- assert( pPg->pNextHash==0 && pPg->pPrevHash==0 );
- return;
- }
- if( pPg->pNextHash ){
- pPg->pNextHash->pPrevHash = pPg->pPrevHash;
- }
- if( pPg->pPrevHash ){
- assert( pPager->aHash[pPg->pgno & (pPager->nHash-1)]!=pPg );
- pPg->pPrevHash->pNextHash = pPg->pNextHash;
- }else{
- int h = pPg->pgno & (pPager->nHash-1);
- pPager->aHash[h] = pPg->pNextHash;
- }
- if( MEMDB ){
- clearHistory(PGHDR_TO_HIST(pPg, pPager));
- }
- pPg->pgno = 0;
- pPg->pNextHash = pPg->pPrevHash = 0;
-}
-
-/*
-** Unlink a page from the free list (the list of all pages where nRef==0)
-** and from its hash collision chain.
-*/
-static void unlinkPage(PgHdr *pPg){
- Pager *pPager = pPg->pPager;
-
- /* Unlink from free page list */
- lruListRemove(pPg);
-
- /* Unlink from the pgno hash table */
- unlinkHashChain(pPager, pPg);
-}
-
-/*
-** This routine is used to truncate the cache when a database
-** is truncated. Drop from the cache all pages whose pgno is
-** larger than pPager->dbSize and is unreferenced.
-**
-** Referenced pages larger than pPager->dbSize are zeroed.
-**
-** Actually, at the point this routine is called, it would be
-** an error to have a referenced page. But rather than delete
-** that page and guarantee a subsequent segfault, it seems better
-** to zero it and hope that we error out sanely.
-*/
-static void pager_truncate_cache(Pager *pPager){
- PgHdr *pPg;
- PgHdr **ppPg;
- int dbSize = pPager->dbSize;
-
- ppPg = &pPager->pAll;
- while( (pPg = *ppPg)!=0 ){
- if( pPg->pgno<=dbSize ){
- ppPg = &pPg->pNextAll;
- }else if( pPg->nRef>0 ){
- memset(PGHDR_TO_DATA(pPg), 0, pPager->pageSize);
- ppPg = &pPg->pNextAll;
- }else{
- *ppPg = pPg->pNextAll;
- IOTRACE(("PGFREE %p %d\n", pPager, pPg->pgno));
- PAGER_INCR(sqlite3_pager_pgfree_count);
- unlinkPage(pPg);
- makeClean(pPg);
- sqlite3_free(pPg);
- pPager->nPage--;
- }
- }
-}
-
-/*
-** Try to obtain a lock on a file. Invoke the busy callback if the lock
-** is currently not available. Repeat until the busy callback returns
-** false or until the lock succeeds.
-**
-** Return SQLITE_OK on success and an error code if we cannot obtain
-** the lock.
-*/
-static int pager_wait_on_lock(Pager *pPager, int locktype){
- int rc;
-
- /* The OS lock values must be the same as the Pager lock values */
- assert( PAGER_SHARED==SHARED_LOCK );
- assert( PAGER_RESERVED==RESERVED_LOCK );
- assert( PAGER_EXCLUSIVE==EXCLUSIVE_LOCK );
-
- /* If the file is currently unlocked then the size must be unknown */
- assert( pPager->state>=PAGER_SHARED || pPager->dbSize<0 || MEMDB );
-
- if( pPager->state>=locktype ){
- rc = SQLITE_OK;
- }else{
- do {
- rc = sqlite3OsLock(pPager->fd, locktype);
- }while( rc==SQLITE_BUSY && sqlite3InvokeBusyHandler(pPager->pBusyHandler) );
- if( rc==SQLITE_OK ){
- pPager->state = locktype;
- IOTRACE(("LOCK %p %d\n", pPager, locktype))
- }
- }
- return rc;
-}
-
-/*
-** Truncate the file to the number of pages specified.
-*/
-int sqlite3PagerTruncate(Pager *pPager, Pgno nPage){
- int rc;
- assert( pPager->state>=PAGER_SHARED || MEMDB );
- sqlite3PagerPagecount(pPager);
- if( pPager->errCode ){
- rc = pPager->errCode;
- return rc;
- }
- if( nPage>=(unsigned)pPager->dbSize ){
- return SQLITE_OK;
- }
- if( MEMDB ){
- pPager->dbSize = nPage;
- pager_truncate_cache(pPager);
- return SQLITE_OK;
- }
- pagerEnter(pPager);
- rc = syncJournal(pPager);
- pagerLeave(pPager);
- if( rc!=SQLITE_OK ){
- return rc;
- }
-
- /* Get an exclusive lock on the database before truncating. */
- pagerEnter(pPager);
- rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
- pagerLeave(pPager);
- if( rc!=SQLITE_OK ){
- return rc;
- }
-
- rc = pager_truncate(pPager, nPage);
- return rc;
-}
-
-/*
-** Shutdown the page cache. Free all memory and close all files.
-**
-** If a transaction was in progress when this routine is called, that
-** transaction is rolled back. All outstanding pages are invalidated
-** and their memory is freed. Any attempt to use a page associated
-** with this page cache after this function returns will likely
-** result in a coredump.
-**
-** This function always succeeds. If a transaction is active an attempt
-** is made to roll it back. If an error occurs during the rollback
-** a hot journal may be left in the filesystem but no error is returned
-** to the caller.
-*/
-int sqlite3PagerClose(Pager *pPager){
-#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
- if( !MEMDB ){
- sqlite3_mutex *mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM2);
- sqlite3_mutex_enter(mutex);
- if( pPager->pPrev ){
- pPager->pPrev->pNext = pPager->pNext;
- }else{
- sqlite3PagerList = pPager->pNext;
- }
- if( pPager->pNext ){
- pPager->pNext->pPrev = pPager->pPrev;
- }
- sqlite3_mutex_leave(mutex);
- }
-#endif
-
- disable_simulated_io_errors();
- pPager->errCode = 0;
- pPager->exclusiveMode = 0;
- pager_reset(pPager);
- pagerUnlockAndRollback(pPager);
- enable_simulated_io_errors();
- PAGERTRACE2("CLOSE %d\n", PAGERID(pPager));
- IOTRACE(("CLOSE %p\n", pPager))
- assert( pPager->errCode || (pPager->journalOpen==0 && pPager->stmtOpen==0) );
- if( pPager->journalOpen ){
- sqlite3OsClose(pPager->jfd);
- }
- sqlite3_free(pPager->aInJournal);
- if( pPager->stmtOpen ){
- sqlite3OsClose(pPager->stfd);
- }
- sqlite3OsClose(pPager->fd);
- /* Temp files are automatically deleted by the OS
- ** if( pPager->tempFile ){
- ** sqlite3OsDelete(pPager->zFilename);
- ** }
- */
-
- sqlite3_free(pPager->aHash);
- sqlite3_free(pPager->pTmpSpace);
- sqlite3_free(pPager);
- return SQLITE_OK;
-}
-
-#if !defined(NDEBUG) || defined(SQLITE_TEST)
-/*
-** Return the page number for the given page data.
-*/
-Pgno sqlite3PagerPagenumber(DbPage *p){
- return p->pgno;
-}
-#endif
-
-/*
-** The page_ref() function increments the reference count for a page.
-** If the page is currently on the freelist (the reference count is zero) then
-** remove it from the freelist.
-**
-** For non-test systems, page_ref() is a macro that calls _page_ref()
-** online of the reference count is zero. For test systems, page_ref()
-** is a real function so that we can set breakpoints and trace it.
-*/
-static void _page_ref(PgHdr *pPg){
- if( pPg->nRef==0 ){
- /* The page is currently on the freelist. Remove it. */
- lruListRemove(pPg);
- pPg->pPager->nRef++;
- }
- pPg->nRef++;
- REFINFO(pPg);
-}
-#ifdef SQLITE_DEBUG
- static void page_ref(PgHdr *pPg){
- if( pPg->nRef==0 ){
- _page_ref(pPg);
- }else{
- pPg->nRef++;
- REFINFO(pPg);
- }
- }
-#else
-# define page_ref(P) ((P)->nRef==0?_page_ref(P):(void)(P)->nRef++)
-#endif
-
-/*
-** Increment the reference count for a page. The input pointer is
-** a reference to the page data.
-*/
-int sqlite3PagerRef(DbPage *pPg){
- pagerEnter(pPg->pPager);
- page_ref(pPg);
- pagerLeave(pPg->pPager);
- return SQLITE_OK;
-}
-
-/*
-** Sync the journal. In other words, make sure all the pages that have
-** been written to the journal have actually reached the surface of the
-** disk. It is not safe to modify the original database file until after
-** the journal has been synced. If the original database is modified before
-** the journal is synced and a power failure occurs, the unsynced journal
-** data would be lost and we would be unable to completely rollback the
-** database changes. Database corruption would occur.
-**
-** This routine also updates the nRec field in the header of the journal.
-** (See comments on the pager_playback() routine for additional information.)
-** If the sync mode is FULL, two syncs will occur. First the whole journal
-** is synced, then the nRec field is updated, then a second sync occurs.
-**
-** For temporary databases, we do not care if we are able to rollback
-** after a power failure, so no sync occurs.
-**
-** If the IOCAP_SEQUENTIAL flag is set for the persistent media on which
-** the database is stored, then OsSync() is never called on the journal
-** file. In this case all that is required is to update the nRec field in
-** the journal header.
-**
-** This routine clears the needSync field of every page current held in
-** memory.
-*/
-static int syncJournal(Pager *pPager){
- PgHdr *pPg;
- int rc = SQLITE_OK;
-
-
- /* Sync the journal before modifying the main database
- ** (assuming there is a journal and it needs to be synced.)
- */
- if( pPager->needSync ){
- if( !pPager->tempFile ){
- int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
- assert( pPager->journalOpen );
-
- /* assert( !pPager->noSync ); // noSync might be set if synchronous
- ** was turned off after the transaction was started. Ticket #615 */
-#ifndef NDEBUG
- {
- /* Make sure the pPager->nRec counter we are keeping agrees
- ** with the nRec computed from the size of the journal file.
- */
- i64 jSz;
- rc = sqlite3OsFileSize(pPager->jfd, &jSz);
- if( rc!=0 ) return rc;
- assert( pPager->journalOff==jSz );
- }
-#endif
- if( 0==(iDc&SQLITE_IOCAP_SAFE_APPEND) ){
- /* Write the nRec value into the journal file header. If in
- ** full-synchronous mode, sync the journal first. This ensures that
- ** all data has really hit the disk before nRec is updated to mark
- ** it as a candidate for rollback.
- **
- ** This is not required if the persistent media supports the
- ** SAFE_APPEND property. Because in this case it is not possible
- ** for garbage data to be appended to the file, the nRec field
- ** is populated with 0xFFFFFFFF when the journal header is written
- ** and never needs to be updated.
- */
- i64 jrnlOff;
- if( pPager->fullSync && 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){
- PAGERTRACE2("SYNC journal of %d\n", PAGERID(pPager));
- IOTRACE(("JSYNC %p\n", pPager))
- rc = sqlite3OsSync(pPager->jfd, pPager->sync_flags);
- if( rc!=0 ) return rc;
- }
-
- jrnlOff = pPager->journalHdr + sizeof(aJournalMagic);
- IOTRACE(("JHDR %p %lld %d\n", pPager, jrnlOff, 4));
- rc = write32bits(pPager->jfd, jrnlOff, pPager->nRec);
- if( rc ) return rc;
- }
- if( 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){
- PAGERTRACE2("SYNC journal of %d\n", PAGERID(pPager));
- IOTRACE(("JSYNC %p\n", pPager))
- rc = sqlite3OsSync(pPager->jfd, pPager->sync_flags|
- (pPager->sync_flags==SQLITE_SYNC_FULL?SQLITE_SYNC_DATAONLY:0)
- );
- if( rc!=0 ) return rc;
- }
- pPager->journalStarted = 1;
- }
- pPager->needSync = 0;
-
- /* Erase the needSync flag from every page.
- */
- for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
- pPg->needSync = 0;
- }
- lruListSetFirstSynced(pPager);
- }
-
-#ifndef NDEBUG
- /* If the Pager.needSync flag is clear then the PgHdr.needSync
- ** flag must also be clear for all pages. Verify that this
- ** invariant is true.
- */
- else{
- for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
- assert( pPg->needSync==0 );
- }
- assert( pPager->lru.pFirstSynced==pPager->lru.pFirst );
- }
-#endif
-
- return rc;
-}
-
-/*
-** Merge two lists of pages connected by pDirty and in pgno order.
-** Do not both fixing the pPrevDirty pointers.
-*/
-static PgHdr *merge_pagelist(PgHdr *pA, PgHdr *pB){
- PgHdr result, *pTail;
- pTail = &result;
- while( pA && pB ){
- if( pA->pgno<pB->pgno ){
- pTail->pDirty = pA;
- pTail = pA;
- pA = pA->pDirty;
- }else{
- pTail->pDirty = pB;
- pTail = pB;
- pB = pB->pDirty;
- }
- }
- if( pA ){
- pTail->pDirty = pA;
- }else if( pB ){
- pTail->pDirty = pB;
- }else{
- pTail->pDirty = 0;
- }
- return result.pDirty;
-}
-
-/*
-** Sort the list of pages in accending order by pgno. Pages are
-** connected by pDirty pointers. The pPrevDirty pointers are
-** corrupted by this sort.
-*/
-#define N_SORT_BUCKET_ALLOC 25
-#define N_SORT_BUCKET 25
-#ifdef SQLITE_TEST
- int sqlite3_pager_n_sort_bucket = 0;
- #undef N_SORT_BUCKET
- #define N_SORT_BUCKET \
- (sqlite3_pager_n_sort_bucket?sqlite3_pager_n_sort_bucket:N_SORT_BUCKET_ALLOC)
-#endif
-static PgHdr *sort_pagelist(PgHdr *pIn){
- PgHdr *a[N_SORT_BUCKET_ALLOC], *p;
- int i;
- memset(a, 0, sizeof(a));
- while( pIn ){
- p = pIn;
- pIn = p->pDirty;
- p->pDirty = 0;
- for(i=0; i<N_SORT_BUCKET-1; i++){
- if( a[i]==0 ){
- a[i] = p;
- break;
- }else{
- p = merge_pagelist(a[i], p);
- a[i] = 0;
- }
- }
- if( i==N_SORT_BUCKET-1 ){
- /* Coverage: To get here, there need to be 2^(N_SORT_BUCKET)
- ** elements in the input list. This is possible, but impractical.
- ** Testing this line is the point of global variable
- ** sqlite3_pager_n_sort_bucket.
- */
- a[i] = merge_pagelist(a[i], p);
- }
- }
- p = a[0];
- for(i=1; i<N_SORT_BUCKET; i++){
- p = merge_pagelist(p, a[i]);
- }
- return p;
-}
-
-/*
-** Given a list of pages (connected by the PgHdr.pDirty pointer) write
-** every one of those pages out to the database file and mark them all
-** as clean.
-*/
-static int pager_write_pagelist(PgHdr *pList){
- Pager *pPager;
- PgHdr *p;
- int rc;
-
- if( pList==0 ) return SQLITE_OK;
- pPager = pList->pPager;
-
- /* At this point there may be either a RESERVED or EXCLUSIVE lock on the
- ** database file. If there is already an EXCLUSIVE lock, the following
- ** calls to sqlite3OsLock() are no-ops.
- **
- ** Moving the lock from RESERVED to EXCLUSIVE actually involves going
- ** through an intermediate state PENDING. A PENDING lock prevents new
- ** readers from attaching to the database but is unsufficient for us to
- ** write. The idea of a PENDING lock is to prevent new readers from
- ** coming in while we wait for existing readers to clear.
- **
- ** While the pager is in the RESERVED state, the original database file
- ** is unchanged and we can rollback without having to playback the
- ** journal into the original database file. Once we transition to
- ** EXCLUSIVE, it means the database file has been changed and any rollback
- ** will require a journal playback.
- */
- rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
- if( rc!=SQLITE_OK ){
- return rc;
- }
-
- pList = sort_pagelist(pList);
- for(p=pList; p; p=p->pDirty){
- assert( p->dirty );
- p->dirty = 0;
- }
- while( pList ){
-
- /* If the file has not yet been opened, open it now. */
- if( !pPager->fd->isOpen ){
- assert(pPager->tempFile);
- rc = sqlite3PagerOpentemp(pPager->pVfs, pPager->fd, pPager->zFilename,
- pPager->vfsFlags);
- if( rc ) return rc;
- }
-
- /* If there are dirty pages in the page cache with page numbers greater
- ** than Pager.dbSize, this means sqlite3PagerTruncate() was called to
- ** make the file smaller (presumably by auto-vacuum code). Do not write
- ** any such pages to the file.
- */
- if( pList->pgno<=pPager->dbSize ){
- i64 offset = (pList->pgno-1)*(i64)pPager->pageSize;
- char *pData = CODEC2(pPager, PGHDR_TO_DATA(pList), pList->pgno, 6);
- PAGERTRACE4("STORE %d page %d hash(%08x)\n",
- PAGERID(pPager), pList->pgno, pager_pagehash(pList));
- IOTRACE(("PGOUT %p %d\n", pPager, pList->pgno));
- rc = sqlite3OsWrite(pPager->fd, pData, pPager->pageSize, offset);
- PAGER_INCR(sqlite3_pager_writedb_count);
- PAGER_INCR(pPager->nWrite);
- if( pList->pgno==1 ){
- memcpy(&pPager->dbFileVers, &pData[24], sizeof(pPager->dbFileVers));
- }
- }
-#ifndef NDEBUG
- else{
- PAGERTRACE3("NOSTORE %d page %d\n", PAGERID(pPager), pList->pgno);
- }
-#endif
- if( rc ) return rc;
-#ifdef SQLITE_CHECK_PAGES
- pList->pageHash = pager_pagehash(pList);
-#endif
- pList = pList->pDirty;
- }
- return SQLITE_OK;
-}
-
-/*
-** Collect every dirty page into a dirty list and
-** return a pointer to the head of that list. All pages are
-** collected even if they are still in use.
-*/
-static PgHdr *pager_get_all_dirty_pages(Pager *pPager){
- return pPager->pDirty;
-}
-
-/*
-** Return TRUE if there is a hot journal on the given pager.
-** A hot journal is one that needs to be played back.
-**
-** If the current size of the database file is 0 but a journal file
-** exists, that is probably an old journal left over from a prior
-** database with the same name. Just delete the journal.
-*/
-static int hasHotJournal(Pager *pPager){
- sqlite3_vfs *pVfs = pPager->pVfs;
- if( !pPager->useJournal ) return 0;
- if( !pPager->fd->isOpen ) return 0;
- if( !sqlite3OsAccess(pVfs, pPager->zJournal, SQLITE_ACCESS_EXISTS) ){
- return 0;
- }
- if( sqlite3OsCheckReservedLock(pPager->fd) ){
- return 0;
- }
- if( sqlite3PagerPagecount(pPager)==0 ){
- sqlite3OsDelete(pVfs, pPager->zJournal, 0);
- return 0;
- }else{
- return 1;
- }
-}
-
-/*
-** Try to find a page in the cache that can be recycled.
-**
-** This routine may return SQLITE_IOERR, SQLITE_FULL or SQLITE_OK. It
-** does not set the pPager->errCode variable.
-*/
-static int pager_recycle(Pager *pPager, PgHdr **ppPg){
- PgHdr *pPg;
- *ppPg = 0;
-
- /* It is illegal to call this function unless the pager object
- ** pointed to by pPager has at least one free page (page with nRef==0).
- */
- assert(!MEMDB);
- assert(pPager->lru.pFirst);
-
- /* Find a page to recycle. Try to locate a page that does not
- ** require us to do an fsync() on the journal.
- */
- pPg = pPager->lru.pFirstSynced;
-
- /* If we could not find a page that does not require an fsync()
- ** on the journal file then fsync the journal file. This is a
- ** very slow operation, so we work hard to avoid it. But sometimes
- ** it can't be helped.
- */
- if( pPg==0 && pPager->lru.pFirst){
- int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
- int rc = syncJournal(pPager);
- if( rc!=0 ){
- return rc;
- }
- if( pPager->fullSync && 0==(iDc&SQLITE_IOCAP_SAFE_APPEND) ){
- /* If in full-sync mode, write a new journal header into the
- ** journal file. This is done to avoid ever modifying a journal
- ** header that is involved in the rollback of pages that have
- ** already been written to the database (in case the header is
- ** trashed when the nRec field is updated).
- */
- pPager->nRec = 0;
- assert( pPager->journalOff > 0 );
- assert( pPager->doNotSync==0 );
- rc = writeJournalHdr(pPager);
- if( rc!=0 ){
- return rc;
- }
- }
- pPg = pPager->lru.pFirst;
- }
-
- assert( pPg->nRef==0 );
-
- /* Write the page to the database file if it is dirty.
- */
- if( pPg->dirty ){
- int rc;
- assert( pPg->needSync==0 );
- makeClean(pPg);
- pPg->dirty = 1;
- pPg->pDirty = 0;
- rc = pager_write_pagelist( pPg );
- pPg->dirty = 0;
- if( rc!=SQLITE_OK ){
- return rc;
- }
- }
- assert( pPg->dirty==0 );
-
- /* If the page we are recycling is marked as alwaysRollback, then
- ** set the global alwaysRollback flag, thus disabling the
- ** sqlite3PagerDontRollback() optimization for the rest of this transaction.
- ** It is necessary to do this because the page marked alwaysRollback
- ** might be reloaded at a later time but at that point we won't remember
- ** that is was marked alwaysRollback. This means that all pages must
- ** be marked as alwaysRollback from here on out.
- */
- if( pPg->alwaysRollback ){
- IOTRACE(("ALWAYS_ROLLBACK %p\n", pPager))
- pPager->alwaysRollback = 1;
- }
-
- /* Unlink the old page from the free list and the hash table
- */
- unlinkPage(pPg);
- assert( pPg->pgno==0 );
-
- *ppPg = pPg;
- return SQLITE_OK;
-}
-
-#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
-/*
-** This function is called to free superfluous dynamically allocated memory
-** held by the pager system. Memory in use by any SQLite pager allocated
-** by the current thread may be sqlite3_free()ed.
-**
-** nReq is the number of bytes of memory required. Once this much has
-** been released, the function returns. The return value is the total number
-** of bytes of memory released.
-*/
-int sqlite3PagerReleaseMemory(int nReq){
- int nReleased = 0; /* Bytes of memory released so far */
- sqlite3_mutex *mutex; /* The MEM2 mutex */
- Pager *pPager; /* For looping over pagers */
- BusyHandler *savedBusy; /* Saved copy of the busy handler */
- int rc = SQLITE_OK;
-
- /* Acquire the memory-management mutex
- */
- mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM2);
- sqlite3_mutex_enter(mutex);
-
- /* Signal all database connections that memory management wants
- ** to have access to the pagers.
- */
- for(pPager=sqlite3PagerList; pPager; pPager=pPager->pNext){
- pPager->iInUseMM = 1;
- }
-
- while( rc==SQLITE_OK && (nReq<0 || nReleased<nReq) ){
- PgHdr *pPg;
- PgHdr *pRecycled;
-
- /* Try to find a page to recycle that does not require a sync(). If
- ** this is not possible, find one that does require a sync().
- */
- sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU));
- pPg = sqlite3LruPageList.pFirstSynced;
- while( pPg && (pPg->needSync || pPg->pPager->iInUseDB) ){
- pPg = pPg->gfree.pNext;
- }
- if( !pPg ){
- pPg = sqlite3LruPageList.pFirst;
- while( pPg && pPg->pPager->iInUseDB ){
- pPg = pPg->gfree.pNext;
- }
- }
- sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU));
-
- /* If pPg==0, then the block above has failed to find a page to
- ** recycle. In this case return early - no further memory will
- ** be released.
- */
- if( !pPg ) break;
-
- pPager = pPg->pPager;
- assert(!pPg->needSync || pPg==pPager->lru.pFirst);
- assert(pPg->needSync || pPg==pPager->lru.pFirstSynced);
-
- savedBusy = pPager->pBusyHandler;
- pPager->pBusyHandler = 0;
- rc = pager_recycle(pPager, &pRecycled);
- pPager->pBusyHandler = savedBusy;
- assert(pRecycled==pPg || rc!=SQLITE_OK);
- if( rc==SQLITE_OK ){
- /* We've found a page to free. At this point the page has been
- ** removed from the page hash-table, free-list and synced-list
- ** (pFirstSynced). It is still in the all pages (pAll) list.
- ** Remove it from this list before freeing.
- **
- ** Todo: Check the Pager.pStmt list to make sure this is Ok. It
- ** probably is though.
- */
- PgHdr *pTmp;
- assert( pPg );
- if( pPg==pPager->pAll ){
- pPager->pAll = pPg->pNextAll;
- }else{
- for( pTmp=pPager->pAll; pTmp->pNextAll!=pPg; pTmp=pTmp->pNextAll ){}
- pTmp->pNextAll = pPg->pNextAll;
- }
- nReleased += (
- sizeof(*pPg) + pPager->pageSize
- + sizeof(u32) + pPager->nExtra
- + MEMDB*sizeof(PgHistory)
- );
- IOTRACE(("PGFREE %p %d *\n", pPager, pPg->pgno));
- PAGER_INCR(sqlite3_pager_pgfree_count);
- sqlite3_free(pPg);
- pPager->nPage--;
- }else{
- /* An error occured whilst writing to the database file or
- ** journal in pager_recycle(). The error is not returned to the
- ** caller of this function. Instead, set the Pager.errCode variable.
- ** The error will be returned to the user (or users, in the case
- ** of a shared pager cache) of the pager for which the error occured.
- */
- assert(
- (rc&0xff)==SQLITE_IOERR ||
- rc==SQLITE_FULL ||
- rc==SQLITE_BUSY
- );
- assert( pPager->state>=PAGER_RESERVED );
- pager_error(pPager, rc);
- }
- }
-
- /* Clear the memory management flags and release the mutex
- */
- for(pPager=sqlite3PagerList; pPager; pPager=pPager->pNext){
- pPager->iInUseMM = 0;
- }
- sqlite3_mutex_leave(mutex);
-
- /* Return the number of bytes released
- */
- return nReleased;
-}
-#endif /* SQLITE_ENABLE_MEMORY_MANAGEMENT */
-
-/*
-** Read the content of page pPg out of the database file.
-*/
-static int readDbPage(Pager *pPager, PgHdr *pPg, Pgno pgno){
- int rc;
- i64 offset;
- assert( MEMDB==0 );
- assert(pPager->fd->pMethods||pPager->tempFile);
- if( !pPager->fd->isOpen ){
- return SQLITE_IOERR_SHORT_READ;
- }
- offset = (pgno-1)*(i64)pPager->pageSize;
- rc = sqlite3OsRead(pPager->fd, PGHDR_TO_DATA(pPg), pPager->pageSize, offset);
- PAGER_INCR(sqlite3_pager_readdb_count);
- PAGER_INCR(pPager->nRead);
- IOTRACE(("PGIN %p %d\n", pPager, pgno));
- if( pgno==1 ){
- memcpy(&pPager->dbFileVers, &((u8*)PGHDR_TO_DATA(pPg))[24],
- sizeof(pPager->dbFileVers));
- }
- CODEC1(pPager, PGHDR_TO_DATA(pPg), pPg->pgno, 3);
- PAGERTRACE4("FETCH %d page %d hash(%08x)\n",
- PAGERID(pPager), pPg->pgno, pager_pagehash(pPg));
- return rc;
-}
-
-
-/*
-** This function is called to obtain the shared lock required before
-** data may be read from the pager cache. If the shared lock has already
-** been obtained, this function is a no-op.
-**
-** Immediately after obtaining the shared lock (if required), this function
-** checks for a hot-journal file. If one is found, an emergency rollback
-** is performed immediately.
-*/
-static int pagerSharedLock(Pager *pPager){
- int rc = SQLITE_OK;
- int isHot = 0;
-
- /* If this database is opened for exclusive access, has no outstanding
- ** page references and is in an error-state, now is the chance to clear
- ** the error. Discard the contents of the pager-cache and treat any
- ** open journal file as a hot-journal.
- */
- if( !MEMDB && pPager->exclusiveMode && pPager->nRef==0 && pPager->errCode ){
- if( pPager->journalOpen ){
- isHot = 1;
- }
- pager_reset(pPager);
- pPager->errCode = SQLITE_OK;
- }
-
- /* If the pager is still in an error state, do not proceed. The error
- ** state will be cleared at some point in the future when all page
- ** references are dropped and the cache can be discarded.
- */
- if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
- return pPager->errCode;
- }
-
- if( pPager->state==PAGER_UNLOCK || isHot ){
- sqlite3_vfs *pVfs = pPager->pVfs;
- if( !MEMDB ){
- assert( pPager->nRef==0 );
- if( !pPager->noReadlock ){
- rc = pager_wait_on_lock(pPager, SHARED_LOCK);
- if( rc!=SQLITE_OK ){
- return pager_error(pPager, rc);
- }
- assert( pPager->state>=SHARED_LOCK );
- }
-
- /* If a journal file exists, and there is no RESERVED lock on the
- ** database file, then it either needs to be played back or deleted.
- */
- if( hasHotJournal(pPager) || isHot ){
- /* Get an EXCLUSIVE lock on the database file. At this point it is
- ** important that a RESERVED lock is not obtained on the way to the
- ** EXCLUSIVE lock. If it were, another process might open the
- ** database file, detect the RESERVED lock, and conclude that the
- ** database is safe to read while this process is still rolling it
- ** back.
- **
- ** Because the intermediate RESERVED lock is not requested, the
- ** second process will get to this point in the code and fail to
- ** obtain its own EXCLUSIVE lock on the database file.
- */
- if( pPager->state<EXCLUSIVE_LOCK ){
- rc = sqlite3OsLock(pPager->fd, EXCLUSIVE_LOCK);
- if( rc!=SQLITE_OK ){
- pager_unlock(pPager);
- return pager_error(pPager, rc);
- }
- pPager->state = PAGER_EXCLUSIVE;
- }
-
- /* Open the journal for reading only. Return SQLITE_BUSY if
- ** we are unable to open the journal file.
- **
- ** The journal file does not need to be locked itself. The
- ** journal file is never open unless the main database file holds
- ** a write lock, so there is never any chance of two or more
- ** processes opening the journal at the same time.
- **
- ** Open the journal for read/write access. This is because in
- ** exclusive-access mode the file descriptor will be kept open and
- ** possibly used for a transaction later on. On some systems, the
- ** OsTruncate() call used in exclusive-access mode also requires
- ** a read/write file handle.
- */
- if( !isHot ){
- rc = SQLITE_BUSY;
- if( sqlite3OsAccess(pVfs, pPager->zJournal, SQLITE_ACCESS_EXISTS) ){
- int fout = 0;
- int f = SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_JOURNAL;
- assert( !pPager->tempFile );
- rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, f, &fout);
- assert( rc!=SQLITE_OK || pPager->jfd->pMethods );
- if( fout&SQLITE_OPEN_READONLY ){
- rc = SQLITE_BUSY;
- sqlite3OsClose(pPager->jfd);
- }
- }
- }
- if( rc!=SQLITE_OK ){
- pager_unlock(pPager);
- return ((rc==SQLITE_NOMEM||rc==SQLITE_IOERR_NOMEM)?rc:SQLITE_BUSY);
- }
- pPager->journalOpen = 1;
- pPager->journalStarted = 0;
- pPager->journalOff = 0;
- pPager->setMaster = 0;
- pPager->journalHdr = 0;
-
- /* Playback and delete the journal. Drop the database write
- ** lock and reacquire the read lock.
- */
- rc = pager_playback(pPager, 1);
- if( rc!=SQLITE_OK ){
- return pager_error(pPager, rc);
- }
- assert(pPager->state==PAGER_SHARED ||
- (pPager->exclusiveMode && pPager->state>PAGER_SHARED)
- );
- }
-
- if( pPager->pAll ){
- /* The shared-lock has just been acquired on the database file
- ** and there are already pages in the cache (from a previous
- ** read or write transaction). Check to see if the database
- ** has been modified. If the database has changed, flush the
- ** cache.
- **
- ** Database changes is detected by looking at 15 bytes beginning
- ** at offset 24 into the file. The first 4 of these 16 bytes are
- ** a 32-bit counter that is incremented with each change. The
- ** other bytes change randomly with each file change when
- ** a codec is in use.
- **
- ** There is a vanishingly small chance that a change will not be
- ** detected. The chance of an undetected change is so small that
- ** it can be neglected.
- */
- char dbFileVers[sizeof(pPager->dbFileVers)];
- sqlite3PagerPagecount(pPager);
-
- if( pPager->errCode ){
- return pPager->errCode;
- }
-
- if( pPager->dbSize>0 ){
- IOTRACE(("CKVERS %p %d\n", pPager, sizeof(dbFileVers)));
- rc = sqlite3OsRead(pPager->fd, &dbFileVers, sizeof(dbFileVers), 24);
- if( rc!=SQLITE_OK ){
- return rc;
- }
- }else{
- memset(dbFileVers, 0, sizeof(dbFileVers));
- }
-
- if( memcmp(pPager->dbFileVers, dbFileVers, sizeof(dbFileVers))!=0 ){
- pager_reset(pPager);
- }
- }
- }
- assert( pPager->exclusiveMode || pPager->state<=PAGER_SHARED );
- if( pPager->state==PAGER_UNLOCK ){
- pPager->state = PAGER_SHARED;
- }
- }
-
- return rc;
-}
-
-/*
-** Allocate a PgHdr object. Either create a new one or reuse
-** an existing one that is not otherwise in use.
-**
-** A new PgHdr structure is created if any of the following are
-** true:
-**
-** (1) We have not exceeded our maximum allocated cache size
-** as set by the "PRAGMA cache_size" command.
-**
-** (2) There are no unused PgHdr objects available at this time.
-**
-** (3) This is an in-memory database.
-**
-** (4) There are no PgHdr objects that do not require a journal
-** file sync and a sync of the journal file is currently
-** prohibited.
-**
-** Otherwise, reuse an existing PgHdr. In other words, reuse an
-** existing PgHdr if all of the following are true:
-**
-** (1) We have reached or exceeded the maximum cache size
-** allowed by "PRAGMA cache_size".
-**
-** (2) There is a PgHdr available with PgHdr->nRef==0
-**
-** (3) We are not in an in-memory database
-**
-** (4) Either there is an available PgHdr that does not need
-** to be synced to disk or else disk syncing is currently
-** allowed.
-*/
-static int pagerAllocatePage(Pager *pPager, PgHdr **ppPg){
- int rc = SQLITE_OK;
- PgHdr *pPg;
- int nByteHdr;
-
- /* Create a new PgHdr if any of the four conditions defined
- ** above are met: */
- if( pPager->nPage<pPager->mxPage
- || pPager->lru.pFirst==0
- || MEMDB
- || (pPager->lru.pFirstSynced==0 && pPager->doNotSync)
- ){
- if( pPager->nPage>=pPager->nHash ){
- pager_resize_hash_table(pPager,
- pPager->nHash<256 ? 256 : pPager->nHash*2);
- if( pPager->nHash==0 ){
- rc = SQLITE_NOMEM;
- goto pager_allocate_out;
- }
- }
- pagerLeave(pPager);
- nByteHdr = sizeof(*pPg) + sizeof(u32) + pPager->nExtra
- + MEMDB*sizeof(PgHistory);
- pPg = (PgHdr*)sqlite3_malloc( nByteHdr + pPager->pageSize );
- pagerEnter(pPager);
- if( pPg==0 ){
- rc = SQLITE_NOMEM;
- goto pager_allocate_out;
- }
- memset(pPg, 0, nByteHdr);
- pPg->pData = (void*)(nByteHdr + (char*)pPg);
- pPg->pPager = pPager;
- pPg->pNextAll = pPager->pAll;
- pPager->pAll = pPg;
- pPager->nPage++;
- }else{
- /* Recycle an existing page with a zero ref-count. */
- rc = pager_recycle(pPager, &pPg);
- if( rc==SQLITE_BUSY ){
- rc = SQLITE_IOERR_BLOCKED;
- }
- if( rc!=SQLITE_OK ){
- goto pager_allocate_out;
- }
- assert( pPager->state>=SHARED_LOCK );
- assert(pPg);
- }
- *ppPg = pPg;
-
-pager_allocate_out:
- return rc;
-}
-
-/*
-** Make sure we have the content for a page. If the page was
-** previously acquired with noContent==1, then the content was
-** just initialized to zeros instead of being read from disk.
-** But now we need the real data off of disk. So make sure we
-** have it. Read it in if we do not have it already.
-*/
-static int pager_get_content(PgHdr *pPg){
- if( pPg->needRead ){
- int rc = readDbPage(pPg->pPager, pPg, pPg->pgno);
- if( rc==SQLITE_OK ){
- pPg->needRead = 0;
- }else{
- return rc;
- }
- }
- return SQLITE_OK;
-}
-
-/*
-** Acquire a page.
-**
-** A read lock on the disk file is obtained when the first page is acquired.
-** This read lock is dropped when the last page is released.
-**
-** This routine works for any page number greater than 0. If the database
-** file is smaller than the requested page, then no actual disk
-** read occurs and the memory image of the page is initialized to
-** all zeros. The extra data appended to a page is always initialized
-** to zeros the first time a page is loaded into memory.
-**
-** The acquisition might fail for several reasons. In all cases,
-** an appropriate error code is returned and *ppPage is set to NULL.
-**
-** See also sqlite3PagerLookup(). Both this routine and Lookup() attempt
-** to find a page in the in-memory cache first. If the page is not already
-** in memory, this routine goes to disk to read it in whereas Lookup()
-** just returns 0. This routine acquires a read-lock the first time it
-** has to go to disk, and could also playback an old journal if necessary.
-** Since Lookup() never goes to disk, it never has to deal with locks
-** or journal files.
-**
-** If noContent is false, the page contents are actually read from disk.
-** If noContent is true, it means that we do not care about the contents
-** of the page at this time, so do not do a disk read. Just fill in the
-** page content with zeros. But mark the fact that we have not read the
-** content by setting the PgHdr.needRead flag. Later on, if
-** sqlite3PagerWrite() is called on this page or if this routine is
-** called again with noContent==0, that means that the content is needed
-** and the disk read should occur at that point.
-*/
-static int pagerAcquire(
- Pager *pPager, /* The pager open on the database file */
- Pgno pgno, /* Page number to fetch */
- DbPage **ppPage, /* Write a pointer to the page here */
- int noContent /* Do not bother reading content from disk if true */
-){
- PgHdr *pPg;
- int rc;
-
- assert( pPager->state==PAGER_UNLOCK || pPager->nRef>0 || pgno==1 );
-
- /* The maximum page number is 2^31. Return SQLITE_CORRUPT if a page
- ** number greater than this, or zero, is requested.
- */
- if( pgno>PAGER_MAX_PGNO || pgno==0 || pgno==PAGER_MJ_PGNO(pPager) ){
- return SQLITE_CORRUPT_BKPT;
- }
-
- /* Make sure we have not hit any critical errors.
- */
- assert( pPager!=0 );
- *ppPage = 0;
-
- /* If this is the first page accessed, then get a SHARED lock
- ** on the database file. pagerSharedLock() is a no-op if
- ** a database lock is already held.
- */
- rc = pagerSharedLock(pPager);
- if( rc!=SQLITE_OK ){
- return rc;
- }
- assert( pPager->state!=PAGER_UNLOCK );
-
- pPg = pager_lookup(pPager, pgno);
- if( pPg==0 ){
- /* The requested page is not in the page cache. */
- int nMax;
- int h;
- PAGER_INCR(pPager->nMiss);
- rc = pagerAllocatePage(pPager, &pPg);
- if( rc!=SQLITE_OK ){
- return rc;
- }
-
- pPg->pgno = pgno;
- assert( !MEMDB || pgno>pPager->stmtSize );
- if( pPager->aInJournal && (int)pgno<=pPager->origDbSize ){
-#if 0
- sqlite3CheckMemory(pPager->aInJournal, pgno/8);
-#endif
- assert( pPager->journalOpen );
- pPg->inJournal = (pPager->aInJournal[pgno/8] & (1<<(pgno&7)))!=0;
- pPg->needSync = 0;
- }else{
- pPg->inJournal = 0;
- pPg->needSync = 0;
- }
-
- makeClean(pPg);
- pPg->nRef = 1;
- REFINFO(pPg);
-
- pPager->nRef++;
- if( pPager->nExtra>0 ){
- memset(PGHDR_TO_EXTRA(pPg, pPager), 0, pPager->nExtra);
- }
- nMax = sqlite3PagerPagecount(pPager);
- if( pPager->errCode ){
- rc = pPager->errCode;
- sqlite3PagerUnref(pPg);
- return rc;
- }
-
- /* Populate the page with data, either by reading from the database
- ** file, or by setting the entire page to zero.
- */
- if( nMax<(int)pgno || MEMDB || (noContent && !pPager->alwaysRollback) ){
- if( pgno>pPager->mxPgno ){
- sqlite3PagerUnref(pPg);
- return SQLITE_FULL;
- }
- memset(PGHDR_TO_DATA(pPg), 0, pPager->pageSize);
- pPg->needRead = noContent && !pPager->alwaysRollback;
- IOTRACE(("ZERO %p %d\n", pPager, pgno));
- }else{
- rc = readDbPage(pPager, pPg, pgno);
- if( rc!=SQLITE_OK && rc!=SQLITE_IOERR_SHORT_READ ){
- pPg->pgno = 0;
- sqlite3PagerUnref(pPg);
- return rc;
- }
- pPg->needRead = 0;
- }
-
- /* Link the page into the page hash table */
- h = pgno & (pPager->nHash-1);
- assert( pgno!=0 );
- pPg->pNextHash = pPager->aHash[h];
- pPager->aHash[h] = pPg;
- if( pPg->pNextHash ){
- assert( pPg->pNextHash->pPrevHash==0 );
- pPg->pNextHash->pPrevHash = pPg;
- }
-
-#ifdef SQLITE_CHECK_PAGES
- pPg->pageHash = pager_pagehash(pPg);
-#endif
- }else{
- /* The requested page is in the page cache. */
- assert(pPager->nRef>0 || pgno==1);
- PAGER_INCR(pPager->nHit);
- if( !noContent ){
- rc = pager_get_content(pPg);
- if( rc ){
- return rc;
- }
- }
- page_ref(pPg);
- }
- *ppPage = pPg;
- return SQLITE_OK;
-}
-int sqlite3PagerAcquire(
- Pager *pPager, /* The pager open on the database file */
- Pgno pgno, /* Page number to fetch */
- DbPage **ppPage, /* Write a pointer to the page here */
- int noContent /* Do not bother reading content from disk if true */
-){
- int rc;
- pagerEnter(pPager);
- rc = pagerAcquire(pPager, pgno, ppPage, noContent);
- pagerLeave(pPager);
- return rc;
-}
-
-
-/*
-** Acquire a page if it is already in the in-memory cache. Do
-** not read the page from disk. Return a pointer to the page,
-** or 0 if the page is not in cache.
-**
-** See also sqlite3PagerGet(). The difference between this routine
-** and sqlite3PagerGet() is that _get() will go to the disk and read
-** in the page if the page is not already in cache. This routine
-** returns NULL if the page is not in cache or if a disk I/O error
-** has ever happened.
-*/
-DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
- PgHdr *pPg = 0;
-
- assert( pPager!=0 );
- assert( pgno!=0 );
-
- pagerEnter(pPager);
- if( pPager->state==PAGER_UNLOCK ){
- assert( !pPager->pAll || pPager->exclusiveMode );
- }else if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
- /* Do nothing */
- }else if( (pPg = pager_lookup(pPager, pgno))!=0 ){
- page_ref(pPg);
- }
- pagerLeave(pPager);
- return pPg;
-}
-
-/*
-** Release a page.
-**
-** If the number of references to the page drop to zero, then the
-** page is added to the LRU list. When all references to all pages
-** are released, a rollback occurs and the lock on the database is
-** removed.
-*/
-int sqlite3PagerUnref(DbPage *pPg){
- Pager *pPager = pPg->pPager;
-
- /* Decrement the reference count for this page
- */
- assert( pPg->nRef>0 );
- pagerEnter(pPg->pPager);
- pPg->nRef--;
- REFINFO(pPg);
-
- CHECK_PAGE(pPg);
-
- /* When the number of references to a page reach 0, call the
- ** destructor and add the page to the freelist.
- */
- if( pPg->nRef==0 ){
-
- lruListAdd(pPg);
- if( pPager->xDestructor ){
- pPager->xDestructor(pPg, pPager->pageSize);
- }
-
- /* When all pages reach the freelist, drop the read lock from
- ** the database file.
- */
- pPager->nRef--;
- assert( pPager->nRef>=0 );
- if( pPager->nRef==0 && (!pPager->exclusiveMode || pPager->journalOff>0) ){
- pagerUnlockAndRollback(pPager);
- }
- }
- pagerLeave(pPager);
- return SQLITE_OK;
-}
-
-/*
-** Create a journal file for pPager. There should already be a RESERVED
-** or EXCLUSIVE lock on the database file when this routine is called.
-**
-** Return SQLITE_OK if everything. Return an error code and release the
-** write lock if anything goes wrong.
-*/
-static int pager_open_journal(Pager *pPager){
- sqlite3_vfs *pVfs = pPager->pVfs;
- int flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_EXCLUSIVE|SQLITE_OPEN_CREATE);
-
- int rc;
- assert( !MEMDB );
- assert( pPager->state>=PAGER_RESERVED );
- assert( pPager->journalOpen==0 );
- assert( pPager->useJournal );
- assert( pPager->aInJournal==0 );
- sqlite3PagerPagecount(pPager);
- pagerLeave(pPager);
- pPager->aInJournal = (u8*)sqlite3MallocZero( pPager->dbSize/8 + 1 );
- pagerEnter(pPager);
- if( pPager->aInJournal==0 ){
- rc = SQLITE_NOMEM;
- goto failed_to_open_journal;
- }
-
- if( pPager->tempFile ){
- flags |= (SQLITE_OPEN_DELETEONCLOSE|SQLITE_OPEN_TEMP_JOURNAL);
- }else{
- flags |= (SQLITE_OPEN_MAIN_JOURNAL);
- }
-#ifdef SQLITE_ENABLE_ATOMIC_WRITE
- rc = sqlite3JournalOpen(
- pVfs, pPager->zJournal, pPager->jfd, flags, jrnlBufferSize(pPager)
- );
-#else
- rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, flags, 0);
-#endif
- assert( rc!=SQLITE_OK || pPager->jfd->pMethods );
- pPager->journalOff = 0;
- pPager->setMaster = 0;
- pPager->journalHdr = 0;
- if( rc!=SQLITE_OK ){
- if( rc==SQLITE_NOMEM ){
- sqlite3OsDelete(pVfs, pPager->zJournal, 0);
- }
- goto failed_to_open_journal;
- }
- pPager->journalOpen = 1;
- pPager->journalStarted = 0;
- pPager->needSync = 0;
- pPager->alwaysRollback = 0;
- pPager->nRec = 0;
- if( pPager->errCode ){
- rc = pPager->errCode;
- goto failed_to_open_journal;
- }
- pPager->origDbSize = pPager->dbSize;
-
- rc = writeJournalHdr(pPager);
-
- if( pPager->stmtAutoopen && rc==SQLITE_OK ){
- rc = sqlite3PagerStmtBegin(pPager);
- }
- if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM && rc!=SQLITE_IOERR_NOMEM ){
- rc = pager_end_transaction(pPager);
- if( rc==SQLITE_OK ){
- rc = SQLITE_FULL;
- }
- }
- return rc;
-
-failed_to_open_journal:
- sqlite3_free(pPager->aInJournal);
- pPager->aInJournal = 0;
- return rc;
-}
-
-/*
-** Acquire a write-lock on the database. The lock is removed when
-** the any of the following happen:
-**
-** * sqlite3PagerCommitPhaseTwo() is called.
-** * sqlite3PagerRollback() is called.
-** * sqlite3PagerClose() is called.
-** * sqlite3PagerUnref() is called to on every outstanding page.
-**
-** The first parameter to this routine is a pointer to any open page of the
-** database file. Nothing changes about the page - it is used merely to
-** acquire a pointer to the Pager structure and as proof that there is
-** already a read-lock on the database.
-**
-** The second parameter indicates how much space in bytes to reserve for a
-** master journal file-name at the start of the journal when it is created.
-**
-** A journal file is opened if this is not a temporary file. For temporary
-** files, the opening of the journal file is deferred until there is an
-** actual need to write to the journal.
-**
-** If the database is already reserved for writing, this routine is a no-op.
-**
-** If exFlag is true, go ahead and get an EXCLUSIVE lock on the file
-** immediately instead of waiting until we try to flush the cache. The
-** exFlag is ignored if a transaction is already active.
-*/
-int sqlite3PagerBegin(DbPage *pPg, int exFlag){
- Pager *pPager = pPg->pPager;
- int rc = SQLITE_OK;
- pagerEnter(pPager);
- assert( pPg->nRef>0 );
- assert( pPager->state!=PAGER_UNLOCK );
- if( pPager->state==PAGER_SHARED ){
- assert( pPager->aInJournal==0 );
- if( MEMDB ){
- pPager->state = PAGER_EXCLUSIVE;
- pPager->origDbSize = pPager->dbSize;
- }else{
- rc = sqlite3OsLock(pPager->fd, RESERVED_LOCK);
- if( rc==SQLITE_OK ){
- pPager->state = PAGER_RESERVED;
- if( exFlag ){
- rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
- }
- }
- if( rc!=SQLITE_OK ){
- pagerLeave(pPager);
- return rc;
- }
- pPager->dirtyCache = 0;
- PAGERTRACE2("TRANSACTION %d\n", PAGERID(pPager));
- if( pPager->useJournal && !pPager->tempFile ){
- rc = pager_open_journal(pPager);
- }
- }
- }else if( pPager->journalOpen && pPager->journalOff==0 ){
- /* This happens when the pager was in exclusive-access mode last
- ** time a (read or write) transaction was successfully concluded
- ** by this connection. Instead of deleting the journal file it was
- ** kept open and truncated to 0 bytes.
- */
- assert( pPager->nRec==0 );
- assert( pPager->origDbSize==0 );
- assert( pPager->aInJournal==0 );
- sqlite3PagerPagecount(pPager);
- pagerLeave(pPager);
- pPager->aInJournal = (u8*)sqlite3MallocZero( pPager->dbSize/8 + 1 );
- pagerEnter(pPager);
- if( !pPager->aInJournal ){
- rc = SQLITE_NOMEM;
- }else{
- pPager->origDbSize = pPager->dbSize;
- rc = writeJournalHdr(pPager);
- }
- }
- assert( !pPager->journalOpen || pPager->journalOff>0 || rc!=SQLITE_OK );
- pagerLeave(pPager);
- return rc;
-}
-
-/*
-** Make a page dirty. Set its dirty flag and add it to the dirty
-** page list.
-*/
-static void makeDirty(PgHdr *pPg){
- if( pPg->dirty==0 ){
- Pager *pPager = pPg->pPager;
- pPg->dirty = 1;
- pPg->pDirty = pPager->pDirty;
- if( pPager->pDirty ){
- pPager->pDirty->pPrevDirty = pPg;
- }
- pPg->pPrevDirty = 0;
- pPager->pDirty = pPg;
- }
-}
-
-/*
-** Make a page clean. Clear its dirty bit and remove it from the
-** dirty page list.
-*/
-static void makeClean(PgHdr *pPg){
- if( pPg->dirty ){
- pPg->dirty = 0;
- if( pPg->pDirty ){
- assert( pPg->pDirty->pPrevDirty==pPg );
- pPg->pDirty->pPrevDirty = pPg->pPrevDirty;
- }
- if( pPg->pPrevDirty ){
- assert( pPg->pPrevDirty->pDirty==pPg );
- pPg->pPrevDirty->pDirty = pPg->pDirty;
- }else{
- assert( pPg->pPager->pDirty==pPg );
- pPg->pPager->pDirty = pPg->pDirty;
- }
- }
-}
-
-
-/*
-** Mark a data page as writeable. The page is written into the journal
-** if it is not there already. This routine must be called before making
-** changes to a page.
-**
-** The first time this routine is called, the pager creates a new
-** journal and acquires a RESERVED lock on the database. If the RESERVED
-** lock could not be acquired, this routine returns SQLITE_BUSY. The
-** calling routine must check for that return value and be careful not to
-** change any page data until this routine returns SQLITE_OK.
-**
-** If the journal file could not be written because the disk is full,
-** then this routine returns SQLITE_FULL and does an immediate rollback.
-** All subsequent write attempts also return SQLITE_FULL until there
-** is a call to sqlite3PagerCommit() or sqlite3PagerRollback() to
-** reset.
-*/
-static int pager_write(PgHdr *pPg){
- void *pData = PGHDR_TO_DATA(pPg);
- Pager *pPager = pPg->pPager;
- int rc = SQLITE_OK;
-
- /* Check for errors
- */
- if( pPager->errCode ){
- return pPager->errCode;
- }
- if( pPager->readOnly ){
- return SQLITE_PERM;
- }
-
- assert( !pPager->setMaster );
-
- CHECK_PAGE(pPg);
-
- /* If this page was previously acquired with noContent==1, that means
- ** we didn't really read in the content of the page. This can happen
- ** (for example) when the page is being moved to the freelist. But
- ** now we are (perhaps) moving the page off of the freelist for
- ** reuse and we need to know its original content so that content
- ** can be stored in the rollback journal. So do the read at this
- ** time.
- */
- rc = pager_get_content(pPg);
- if( rc ){
- return rc;
- }
-
- /* Mark the page as dirty. If the page has already been written
- ** to the journal then we can return right away.
- */
- makeDirty(pPg);
- if( pPg->inJournal && (pageInStatement(pPg) || pPager->stmtInUse==0) ){
- pPager->dirtyCache = 1;
- }else{
-
- /* If we get this far, it means that the page needs to be
- ** written to the transaction journal or the ckeckpoint journal
- ** or both.
- **
- ** First check to see that the transaction journal exists and
- ** create it if it does not.
- */
- assert( pPager->state!=PAGER_UNLOCK );
- rc = sqlite3PagerBegin(pPg, 0);
- if( rc!=SQLITE_OK ){
- return rc;
- }
- assert( pPager->state>=PAGER_RESERVED );
- if( !pPager->journalOpen && pPager->useJournal ){
- rc = pager_open_journal(pPager);
- if( rc!=SQLITE_OK ) return rc;
- }
- assert( pPager->journalOpen || !pPager->useJournal );
- pPager->dirtyCache = 1;
-
- /* The transaction journal now exists and we have a RESERVED or an
- ** EXCLUSIVE lock on the main database file. Write the current page to
- ** the transaction journal if it is not there already.
- */
- if( !pPg->inJournal && (pPager->useJournal || MEMDB) ){
- if( (int)pPg->pgno <= pPager->origDbSize ){
- if( MEMDB ){
- PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
- PAGERTRACE3("JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
- assert( pHist->pOrig==0 );
- pHist->pOrig = (u8*)sqlite3_malloc( pPager->pageSize );
- if( !pHist->pOrig ){
- return SQLITE_NOMEM;
- }
- memcpy(pHist->pOrig, PGHDR_TO_DATA(pPg), pPager->pageSize);
- }else{
- u32 cksum;
- char *pData2;
-
- /* We should never write to the journal file the page that
- ** contains the database locks. The following assert verifies
- ** that we do not. */
- assert( pPg->pgno!=PAGER_MJ_PGNO(pPager) );
- pData2 = CODEC2(pPager, pData, pPg->pgno, 7);
- cksum = pager_cksum(pPager, (u8*)pData2);
- rc = write32bits(pPager->jfd, pPager->journalOff, pPg->pgno);
- if( rc==SQLITE_OK ){
- rc = sqlite3OsWrite(pPager->jfd, pData2, pPager->pageSize,
- pPager->journalOff + 4);
- pPager->journalOff += pPager->pageSize+4;
- }
- if( rc==SQLITE_OK ){
- rc = write32bits(pPager->jfd, pPager->journalOff, cksum);
- pPager->journalOff += 4;
- }
- IOTRACE(("JOUT %p %d %lld %d\n", pPager, pPg->pgno,
- pPager->journalOff, pPager->pageSize));
- PAGER_INCR(sqlite3_pager_writej_count);
- PAGERTRACE5("JOURNAL %d page %d needSync=%d hash(%08x)\n",
- PAGERID(pPager), pPg->pgno, pPg->needSync, pager_pagehash(pPg));
-
- /* An error has occured writing to the journal file. The
- ** transaction will be rolled back by the layer above.
- */
- if( rc!=SQLITE_OK ){
- return rc;
- }
-
- pPager->nRec++;
- assert( pPager->aInJournal!=0 );
- pPager->aInJournal[pPg->pgno/8] |= 1<<(pPg->pgno&7);
- pPg->needSync = !pPager->noSync;
- if( pPager->stmtInUse ){
- pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
- }
- }
- }else{
- pPg->needSync = !pPager->journalStarted && !pPager->noSync;
- PAGERTRACE4("APPEND %d page %d needSync=%d\n",
- PAGERID(pPager), pPg->pgno, pPg->needSync);
- }
- if( pPg->needSync ){
- pPager->needSync = 1;
- }
- pPg->inJournal = 1;
- }
-
- /* If the statement journal is open and the page is not in it,
- ** then write the current page to the statement journal. Note that
- ** the statement journal format differs from the standard journal format
- ** in that it omits the checksums and the header.
- */
- if( pPager->stmtInUse
- && !pageInStatement(pPg)
- && (int)pPg->pgno<=pPager->stmtSize
- ){
- assert( pPg->inJournal || (int)pPg->pgno>pPager->origDbSize );
- if( MEMDB ){
- PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
- assert( pHist->pStmt==0 );
- pHist->pStmt = (u8*)sqlite3_malloc( pPager->pageSize );
- if( pHist->pStmt ){
- memcpy(pHist->pStmt, PGHDR_TO_DATA(pPg), pPager->pageSize);
- }
- PAGERTRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
- page_add_to_stmt_list(pPg);
- }else{
- i64 offset = pPager->stmtNRec*(4+pPager->pageSize);
- char *pData2 = CODEC2(pPager, pData, pPg->pgno, 7);
- rc = write32bits(pPager->stfd, offset, pPg->pgno);
- if( rc==SQLITE_OK ){
- rc = sqlite3OsWrite(pPager->stfd, pData2, pPager->pageSize, offset+4);
- }
- PAGERTRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
- if( rc!=SQLITE_OK ){
- return rc;
- }
- pPager->stmtNRec++;
- assert( pPager->aInStmt!=0 );
- pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
- }
- }
- }
-
- /* Update the database size and return.
- */
- assert( pPager->state>=PAGER_SHARED );
- if( pPager->dbSize<(int)pPg->pgno ){
- pPager->dbSize = pPg->pgno;
- if( !MEMDB && pPager->dbSize==PENDING_BYTE/pPager->pageSize ){
- pPager->dbSize++;
- }
- }
- return rc;
-}
-
-/*
-** This function is used to mark a data-page as writable. It uses
-** pager_write() to open a journal file (if it is not already open)
-** and write the page *pData to the journal.
-**
-** The difference between this function and pager_write() is that this
-** function also deals with the special case where 2 or more pages
-** fit on a single disk sector. In this case all co-resident pages
-** must have been written to the journal file before returning.
-*/
-int sqlite3PagerWrite(DbPage *pDbPage){
- int rc = SQLITE_OK;
-
- PgHdr *pPg = pDbPage;
- Pager *pPager = pPg->pPager;
- Pgno nPagePerSector = (pPager->sectorSize/pPager->pageSize);
-
- pagerEnter(pPager);
- if( !MEMDB && nPagePerSector>1 ){
- Pgno nPageCount; /* Total number of pages in database file */
- Pgno pg1; /* First page of the sector pPg is located on. */
- int nPage; /* Number of pages starting at pg1 to journal */
- int ii;
- int needSync = 0;
-
- /* Set the doNotSync flag to 1. This is because we cannot allow a journal
- ** header to be written between the pages journaled by this function.
- */
- assert( pPager->doNotSync==0 );
- pPager->doNotSync = 1;
-
- /* This trick assumes that both the page-size and sector-size are
- ** an integer power of 2. It sets variable pg1 to the identifier
- ** of the first page of the sector pPg is located on.
- */
- pg1 = ((pPg->pgno-1) & ~(nPagePerSector-1)) + 1;
-
- nPageCount = sqlite3PagerPagecount(pPager);
- if( pPg->pgno>nPageCount ){
- nPage = (pPg->pgno - pg1)+1;
- }else if( (pg1+nPagePerSector-1)>nPageCount ){
- nPage = nPageCount+1-pg1;
- }else{
- nPage = nPagePerSector;
- }
- assert(nPage>0);
- assert(pg1<=pPg->pgno);
- assert((pg1+nPage)>pPg->pgno);
-
- for(ii=0; ii<nPage && rc==SQLITE_OK; ii++){
- Pgno pg = pg1+ii;
- PgHdr *pPage;
- if( !pPager->aInJournal || pg==pPg->pgno ||
- pg>pPager->origDbSize || !(pPager->aInJournal[pg/8]&(1<<(pg&7)))
- ) {
- if( pg!=PAGER_MJ_PGNO(pPager) ){
- rc = sqlite3PagerGet(pPager, pg, &pPage);
- if( rc==SQLITE_OK ){
- rc = pager_write(pPage);
- if( pPage->needSync ){
- needSync = 1;
- }
- sqlite3PagerUnref(pPage);
- }
- }
- }else if( (pPage = pager_lookup(pPager, pg)) ){
- if( pPage->needSync ){
- needSync = 1;
- }
- }
- }
-
- /* If the PgHdr.needSync flag is set for any of the nPage pages
- ** starting at pg1, then it needs to be set for all of them. Because
- ** writing to any of these nPage pages may damage the others, the
- ** journal file must contain sync()ed copies of all of them
- ** before any of them can be written out to the database file.
- */
- if( needSync ){
- for(ii=0; ii<nPage && needSync; ii++){
- PgHdr *pPage = pager_lookup(pPager, pg1+ii);
- if( pPage ) pPage->needSync = 1;
- }
- assert(pPager->needSync);
- }
-
- assert( pPager->doNotSync==1 );
- pPager->doNotSync = 0;
- }else{
- rc = pager_write(pDbPage);
- }
- pagerLeave(pPager);
- return rc;
-}
-
-/*
-** Return TRUE if the page given in the argument was previously passed
-** to sqlite3PagerWrite(). In other words, return TRUE if it is ok
-** to change the content of the page.
-*/
-#ifndef NDEBUG
-int sqlite3PagerIswriteable(DbPage *pPg){
- return pPg->dirty;
-}
-#endif
-
-#ifndef SQLITE_OMIT_VACUUM
-/*
-** Replace the content of a single page with the information in the third
-** argument.
-*/
-int sqlite3PagerOverwrite(Pager *pPager, Pgno pgno, void *pData){
- PgHdr *pPg;
- int rc;
-
- pagerEnter(pPager);
- rc = sqlite3PagerGet(pPager, pgno, &pPg);
- if( rc==SQLITE_OK ){
- rc = sqlite3PagerWrite(pPg);
- if( rc==SQLITE_OK ){
- memcpy(sqlite3PagerGetData(pPg), pData, pPager->pageSize);
- }
- sqlite3PagerUnref(pPg);
- }
- pagerLeave(pPager);
- return rc;
-}
-#endif
-
-/*
-** A call to this routine tells the pager that it is not necessary to
-** write the information on page pPg back to the disk, even though
-** that page might be marked as dirty.
-**
-** The overlying software layer calls this routine when all of the data
-** on the given page is unused. The pager marks the page as clean so
-** that it does not get written to disk.
-**
-** Tests show that this optimization, together with the
-** sqlite3PagerDontRollback() below, more than double the speed
-** of large INSERT operations and quadruple the speed of large DELETEs.
-**
-** When this routine is called, set the alwaysRollback flag to true.
-** Subsequent calls to sqlite3PagerDontRollback() for the same page
-** will thereafter be ignored. This is necessary to avoid a problem
-** where a page with data is added to the freelist during one part of
-** a transaction then removed from the freelist during a later part
-** of the same transaction and reused for some other purpose. When it
-** is first added to the freelist, this routine is called. When reused,
-** the sqlite3PagerDontRollback() routine is called. But because the
-** page contains critical data, we still need to be sure it gets
-** rolled back in spite of the sqlite3PagerDontRollback() call.
-*/
-void sqlite3PagerDontWrite(DbPage *pDbPage){
- PgHdr *pPg = pDbPage;
- Pager *pPager = pPg->pPager;
-
- if( MEMDB ) return;
- pagerEnter(pPager);
- pPg->alwaysRollback = 1;
- if( pPg->dirty && !pPager->stmtInUse ){
- assert( pPager->state>=PAGER_SHARED );
- if( pPager->dbSize==(int)pPg->pgno && pPager->origDbSize<pPager->dbSize ){
- /* If this pages is the last page in the file and the file has grown
- ** during the current transaction, then do NOT mark the page as clean.
- ** When the database file grows, we must make sure that the last page
- ** gets written at least once so that the disk file will be the correct
- ** size. If you do not write this page and the size of the file
- ** on the disk ends up being too small, that can lead to database
- ** corruption during the next transaction.
- */
- }else{
- PAGERTRACE3("DONT_WRITE page %d of %d\n", pPg->pgno, PAGERID(pPager));
- IOTRACE(("CLEAN %p %d\n", pPager, pPg->pgno))
- makeClean(pPg);
-#ifdef SQLITE_CHECK_PAGES
- pPg->pageHash = pager_pagehash(pPg);
-#endif
- }
- }
- pagerLeave(pPager);
-}
-
-/*
-** A call to this routine tells the pager that if a rollback occurs,
-** it is not necessary to restore the data on the given page. This
-** means that the pager does not have to record the given page in the
-** rollback journal.
-**
-** If we have not yet actually read the content of this page (if
-** the PgHdr.needRead flag is set) then this routine acts as a promise
-** that we will never need to read the page content in the future.
-** so the needRead flag can be cleared at this point.
-*/
-void sqlite3PagerDontRollback(DbPage *pPg){
- Pager *pPager = pPg->pPager;
-
- pagerEnter(pPager);
- assert( pPager->state>=PAGER_RESERVED );
- if( pPager->journalOpen==0 ) return;
- if( pPg->alwaysRollback || pPager->alwaysRollback || MEMDB ) return;
- if( !pPg->inJournal && (int)pPg->pgno <= pPager->origDbSize ){
- assert( pPager->aInJournal!=0 );
- pPager->aInJournal[pPg->pgno/8] |= 1<<(pPg->pgno&7);
- pPg->inJournal = 1;
- pPg->needRead = 0;
- if( pPager->stmtInUse ){
- pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
- }
- PAGERTRACE3("DONT_ROLLBACK page %d of %d\n", pPg->pgno, PAGERID(pPager));
- IOTRACE(("GARBAGE %p %d\n", pPager, pPg->pgno))
- }
- if( pPager->stmtInUse
- && !pageInStatement(pPg)
- && (int)pPg->pgno<=pPager->stmtSize
- ){
- assert( pPg->inJournal || (int)pPg->pgno>pPager->origDbSize );
- assert( pPager->aInStmt!=0 );
- pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
- }
- pagerLeave(pPager);
-}
-
-
-/*
-** This routine is called to increment the database file change-counter,
-** stored at byte 24 of the pager file.
-*/
-static int pager_incr_changecounter(Pager *pPager, int isDirect){
- PgHdr *pPgHdr;
- u32 change_counter;
- int rc = SQLITE_OK;
-
- if( !pPager->changeCountDone ){
- /* Open page 1 of the file for writing. */
- rc = sqlite3PagerGet(pPager, 1, &pPgHdr);
- if( rc!=SQLITE_OK ) return rc;
-
- if( !isDirect ){
- rc = sqlite3PagerWrite(pPgHdr);
- if( rc!=SQLITE_OK ){
- sqlite3PagerUnref(pPgHdr);
- return rc;
- }
- }
-
- /* Increment the value just read and write it back to byte 24. */
- change_counter = sqlite3Get4byte((u8*)pPager->dbFileVers);
- change_counter++;
- put32bits(((char*)PGHDR_TO_DATA(pPgHdr))+24, change_counter);
-
- if( isDirect && pPager->fd->isOpen ){
- const void *zBuf = PGHDR_TO_DATA(pPgHdr);
- rc = sqlite3OsWrite(pPager->fd, zBuf, pPager->pageSize, 0);
- }
-
- /* Release the page reference. */
- sqlite3PagerUnref(pPgHdr);
- pPager->changeCountDone = 1;
- }
- return rc;
-}
-
-/*
-** Sync the database file for the pager pPager. zMaster points to the name
-** of a master journal file that should be written into the individual
-** journal file. zMaster may be NULL, which is interpreted as no master
-** journal (a single database transaction).
-**
-** This routine ensures that the journal is synced, all dirty pages written
-** to the database file and the database file synced. The only thing that
-** remains to commit the transaction is to delete the journal file (or
-** master journal file if specified).
-**
-** Note that if zMaster==NULL, this does not overwrite a previous value
-** passed to an sqlite3PagerCommitPhaseOne() call.
-**
-** If parameter nTrunc is non-zero, then the pager file is truncated to
-** nTrunc pages (this is used by auto-vacuum databases).
-*/
-int sqlite3PagerCommitPhaseOne(Pager *pPager, const char *zMaster, Pgno nTrunc){
- int rc = SQLITE_OK;
-
- PAGERTRACE4("DATABASE SYNC: File=%s zMaster=%s nTrunc=%d\n",
- pPager->zFilename, zMaster, nTrunc);
- pagerEnter(pPager);
-
- /* If this is an in-memory db, or no pages have been written to, or this
- ** function has already been called, it is a no-op.
- */
- if( pPager->state!=PAGER_SYNCED && !MEMDB && pPager->dirtyCache ){
- PgHdr *pPg;
-
-#ifdef SQLITE_ENABLE_ATOMIC_WRITE
- /* The atomic-write optimization can be used if all of the
- ** following are true:
- **
- ** + The file-system supports the atomic-write property for
- ** blocks of size page-size, and
- ** + This commit is not part of a multi-file transaction, and
- ** + Exactly one page has been modified and store in the journal file.
- **
- ** If the optimization can be used, then the journal file will never
- ** be created for this transaction.
- */
- int useAtomicWrite = (
- !zMaster &&
- pPager->journalOff==jrnlBufferSize(pPager) &&
- nTrunc==0 &&
- (0==pPager->pDirty || 0==pPager->pDirty->pDirty)
- );
- if( useAtomicWrite ){
- /* Update the nRec field in the journal file. */
- int offset = pPager->journalHdr + sizeof(aJournalMagic);
- assert(pPager->nRec==1);
- rc = write32bits(pPager->jfd, offset, pPager->nRec);
-
- /* Update the db file change counter. The following call will modify
- ** the in-memory representation of page 1 to include the updated
- ** change counter and then write page 1 directly to the database
- ** file. Because of the atomic-write property of the host file-system,
- ** this is safe.
- */
- if( rc==SQLITE_OK ){
- rc = pager_incr_changecounter(pPager, 1);
- }
- }else{
- rc = sqlite3JournalCreate(pPager->jfd);
- }
-
- if( !useAtomicWrite && rc==SQLITE_OK )
-#endif
-
- /* If a master journal file name has already been written to the
- ** journal file, then no sync is required. This happens when it is
- ** written, then the process fails to upgrade from a RESERVED to an
- ** EXCLUSIVE lock. The next time the process tries to commit the
- ** transaction the m-j name will have already been written.
- */
- if( !pPager->setMaster ){
- assert( pPager->journalOpen );
- rc = pager_incr_changecounter(pPager, 0);
- if( rc!=SQLITE_OK ) goto sync_exit;
-#ifndef SQLITE_OMIT_AUTOVACUUM
- if( nTrunc!=0 ){
- /* If this transaction has made the database smaller, then all pages
- ** being discarded by the truncation must be written to the journal
- ** file.
- */
- Pgno i;
- int iSkip = PAGER_MJ_PGNO(pPager);
- for( i=nTrunc+1; i<=pPager->origDbSize; i++ ){
- if( !(pPager->aInJournal[i/8] & (1<<(i&7))) && i!=iSkip ){
- rc = sqlite3PagerGet(pPager, i, &pPg);
- if( rc!=SQLITE_OK ) goto sync_exit;
- rc = sqlite3PagerWrite(pPg);
- sqlite3PagerUnref(pPg);
- if( rc!=SQLITE_OK ) goto sync_exit;
- }
- }
- }
-#endif
- rc = writeMasterJournal(pPager, zMaster);
- if( rc!=SQLITE_OK ) goto sync_exit;
- rc = syncJournal(pPager);
- }
- if( rc!=SQLITE_OK ) goto sync_exit;
-
-#ifndef SQLITE_OMIT_AUTOVACUUM
- if( nTrunc!=0 ){
- rc = sqlite3PagerTruncate(pPager, nTrunc);
- if( rc!=SQLITE_OK ) goto sync_exit;
- }
-#endif
-
- /* Write all dirty pages to the database file */
- pPg = pager_get_all_dirty_pages(pPager);
- rc = pager_write_pagelist(pPg);
- if( rc!=SQLITE_OK ){
- while( pPg && !pPg->dirty ){ pPg = pPg->pDirty; }
- pPager->pDirty = pPg;
- goto sync_exit;
- }
- pPager->pDirty = 0;
-
- /* Sync the database file. */
- if( !pPager->noSync ){
- rc = sqlite3OsSync(pPager->fd, pPager->sync_flags);
- }
- IOTRACE(("DBSYNC %p\n", pPager))
-
- pPager->state = PAGER_SYNCED;
- }else if( MEMDB && nTrunc!=0 ){
- rc = sqlite3PagerTruncate(pPager, nTrunc);
- }
-
-sync_exit:
- if( rc==SQLITE_IOERR_BLOCKED ){
- /* pager_incr_changecounter() may attempt to obtain an exclusive
- * lock to spill the cache and return IOERR_BLOCKED. But since
- * there is no chance the cache is inconsistent, it is
- * better to return SQLITE_BUSY.
- */
- rc = SQLITE_BUSY;
- }
- pagerLeave(pPager);
- return rc;
-}
-
-
-/*
-** Commit all changes to the database and release the write lock.
-**
-** If the commit fails for any reason, a rollback attempt is made
-** and an error code is returned. If the commit worked, SQLITE_OK
-** is returned.
-*/
-int sqlite3PagerCommitPhaseTwo(Pager *pPager){
- int rc;
- PgHdr *pPg;
-
- if( pPager->errCode ){
- return pPager->errCode;
- }
- if( pPager->state<PAGER_RESERVED ){
- return SQLITE_ERROR;
- }
- pagerEnter(pPager);
- PAGERTRACE2("COMMIT %d\n", PAGERID(pPager));
- if( MEMDB ){
- pPg = pager_get_all_dirty_pages(pPager);
- while( pPg ){
- PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
- clearHistory(pHist);
- pPg->dirty = 0;
- pPg->inJournal = 0;
- pHist->inStmt = 0;
- pPg->needSync = 0;
- pHist->pPrevStmt = pHist->pNextStmt = 0;
- pPg = pPg->pDirty;
- }
- pPager->pDirty = 0;
-#ifndef NDEBUG
- for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
- PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
- assert( !pPg->alwaysRollback );
- assert( !pHist->pOrig );
- assert( !pHist->pStmt );
- }
-#endif
- pPager->pStmt = 0;
- pPager->state = PAGER_SHARED;
- return SQLITE_OK;
- }
- assert( pPager->journalOpen || !pPager->dirtyCache );
- assert( pPager->state==PAGER_SYNCED || !pPager->dirtyCache );
- rc = pager_end_transaction(pPager);
- rc = pager_error(pPager, rc);
- pagerLeave(pPager);
- return rc;
-}
-
-/*
-** Rollback all changes. The database falls back to PAGER_SHARED mode.
-** All in-memory cache pages revert to their original data contents.
-** The journal is deleted.
-**
-** This routine cannot fail unless some other process is not following
-** the correct locking protocol or unless some other
-** process is writing trash into the journal file (SQLITE_CORRUPT) or
-** unless a prior malloc() failed (SQLITE_NOMEM). Appropriate error
-** codes are returned for all these occasions. Otherwise,
-** SQLITE_OK is returned.
-*/
-int sqlite3PagerRollback(Pager *pPager){
- int rc;
- PAGERTRACE2("ROLLBACK %d\n", PAGERID(pPager));
- if( MEMDB ){
- PgHdr *p;
- for(p=pPager->pAll; p; p=p->pNextAll){
- PgHistory *pHist;
- assert( !p->alwaysRollback );
- if( !p->dirty ){
- assert( !((PgHistory *)PGHDR_TO_HIST(p, pPager))->pOrig );
- assert( !((PgHistory *)PGHDR_TO_HIST(p, pPager))->pStmt );
- continue;
- }
-
- pHist = PGHDR_TO_HIST(p, pPager);
- if( pHist->pOrig ){
- memcpy(PGHDR_TO_DATA(p), pHist->pOrig, pPager->pageSize);
- PAGERTRACE3("ROLLBACK-PAGE %d of %d\n", p->pgno, PAGERID(pPager));
- }else{
- PAGERTRACE3("PAGE %d is clean on %d\n", p->pgno, PAGERID(pPager));
- }
- clearHistory(pHist);
- p->dirty = 0;
- p->inJournal = 0;
- pHist->inStmt = 0;
- pHist->pPrevStmt = pHist->pNextStmt = 0;
- if( pPager->xReiniter ){
- pPager->xReiniter(p, pPager->pageSize);
- }
- }
- pPager->pDirty = 0;
- pPager->pStmt = 0;
- pPager->dbSize = pPager->origDbSize;
- pager_truncate_cache(pPager);
- pPager->stmtInUse = 0;
- pPager->state = PAGER_SHARED;
- return SQLITE_OK;
- }
-
- pagerEnter(pPager);
- if( !pPager->dirtyCache || !pPager->journalOpen ){
- rc = pager_end_transaction(pPager);
- pagerLeave(pPager);
- return rc;
- }
-
- if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
- if( pPager->state>=PAGER_EXCLUSIVE ){
- pager_playback(pPager, 0);
- }
- pagerLeave(pPager);
- return pPager->errCode;
- }
- if( pPager->state==PAGER_RESERVED ){
- int rc2;
- rc = pager_playback(pPager, 0);
- rc2 = pager_end_transaction(pPager);
- if( rc==SQLITE_OK ){
- rc = rc2;
- }
- }else{
- rc = pager_playback(pPager, 0);
- }
- /* pager_reset(pPager); */
- pPager->dbSize = -1;
-
- /* If an error occurs during a ROLLBACK, we can no longer trust the pager
- ** cache. So call pager_error() on the way out to make any error
- ** persistent.
- */
- rc = pager_error(pPager, rc);
- pagerLeave(pPager);
- return rc;
-}
-
-/*
-** Return TRUE if the database file is opened read-only. Return FALSE
-** if the database is (in theory) writable.
-*/
-int sqlite3PagerIsreadonly(Pager *pPager){
- return pPager->readOnly;
-}
-
-/*
-** Return the number of references to the pager.
-*/
-int sqlite3PagerRefcount(Pager *pPager){
- return pPager->nRef;
-}
-
-#ifdef SQLITE_TEST
-/*
-** This routine is used for testing and analysis only.
-*/
-int *sqlite3PagerStats(Pager *pPager){
- static int a[11];
- a[0] = pPager->nRef;
- a[1] = pPager->nPage;
- a[2] = pPager->mxPage;
- a[3] = pPager->dbSize;
- a[4] = pPager->state;
- a[5] = pPager->errCode;
- a[6] = pPager->nHit;
- a[7] = pPager->nMiss;
- a[8] = 0; /* Used to be pPager->nOvfl */
- a[9] = pPager->nRead;
- a[10] = pPager->nWrite;
- return a;
-}
-#endif
-
-/*
-** Set the statement rollback point.
-**
-** This routine should be called with the transaction journal already
-** open. A new statement journal is created that can be used to rollback
-** changes of a single SQL command within a larger transaction.
-*/
-static int pagerStmtBegin(Pager *pPager){
- int rc;
- assert( !pPager->stmtInUse );
- assert( pPager->state>=PAGER_SHARED );
- assert( pPager->dbSize>=0 );
- PAGERTRACE2("STMT-BEGIN %d\n", PAGERID(pPager));
- if( MEMDB ){
- pPager->stmtInUse = 1;
- pPager->stmtSize = pPager->dbSize;
- return SQLITE_OK;
- }
- if( !pPager->journalOpen ){
- pPager->stmtAutoopen = 1;
- return SQLITE_OK;
- }
- assert( pPager->journalOpen );
- pagerLeave(pPager);
- assert( pPager->aInStmt==0 );
- pPager->aInStmt = (u8*)sqlite3MallocZero( pPager->dbSize/8 + 1 );
- pagerEnter(pPager);
- if( pPager->aInStmt==0 ){
- /* sqlite3OsLock(pPager->fd, SHARED_LOCK); */
- return SQLITE_NOMEM;
- }
-#ifndef NDEBUG
- rc = sqlite3OsFileSize(pPager->jfd, &pPager->stmtJSize);
- if( rc ) goto stmt_begin_failed;
- assert( pPager->stmtJSize == pPager->journalOff );
-#endif
- pPager->stmtJSize = pPager->journalOff;
- pPager->stmtSize = pPager->dbSize;
- pPager->stmtHdrOff = 0;
- pPager->stmtCksum = pPager->cksumInit;
- if( !pPager->stmtOpen ){
- rc = sqlite3PagerOpentemp(pPager->pVfs, pPager->stfd, pPager->zStmtJrnl,
- SQLITE_OPEN_SUBJOURNAL);
- if( rc ){
- goto stmt_begin_failed;
- }
- pPager->stmtOpen = 1;
- pPager->stmtNRec = 0;
- }
- pPager->stmtInUse = 1;
- return SQLITE_OK;
-
-stmt_begin_failed:
- if( pPager->aInStmt ){
- sqlite3_free(pPager->aInStmt);
- pPager->aInStmt = 0;
- }
- return rc;
-}
-int sqlite3PagerStmtBegin(Pager *pPager){
- int rc;
- pagerEnter(pPager);
- rc = pagerStmtBegin(pPager);
- pagerLeave(pPager);
- return rc;
-}
-
-/*
-** Commit a statement.
-*/
-int sqlite3PagerStmtCommit(Pager *pPager){
- pagerEnter(pPager);
- if( pPager->stmtInUse ){
- PgHdr *pPg, *pNext;
- PAGERTRACE2("STMT-COMMIT %d\n", PAGERID(pPager));
- if( !MEMDB ){
- /* sqlite3OsTruncate(pPager->stfd, 0); */
- sqlite3_free( pPager->aInStmt );
- pPager->aInStmt = 0;
- }else{
- for(pPg=pPager->pStmt; pPg; pPg=pNext){
- PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
- pNext = pHist->pNextStmt;
- assert( pHist->inStmt );
- pHist->inStmt = 0;
- pHist->pPrevStmt = pHist->pNextStmt = 0;
- sqlite3_free(pHist->pStmt);
- pHist->pStmt = 0;
- }
- }
- pPager->stmtNRec = 0;
- pPager->stmtInUse = 0;
- pPager->pStmt = 0;
- }
- pPager->stmtAutoopen = 0;
- pagerLeave(pPager);
- return SQLITE_OK;
-}
-
-/*
-** Rollback a statement.
-*/
-int sqlite3PagerStmtRollback(Pager *pPager){
- int rc;
- pagerEnter(pPager);
- if( pPager->stmtInUse ){
- PAGERTRACE2("STMT-ROLLBACK %d\n", PAGERID(pPager));
- if( MEMDB ){
- PgHdr *pPg;
- PgHistory *pHist;
- for(pPg=pPager->pStmt; pPg; pPg=pHist->pNextStmt){
- pHist = PGHDR_TO_HIST(pPg, pPager);
- if( pHist->pStmt ){
- memcpy(PGHDR_TO_DATA(pPg), pHist->pStmt, pPager->pageSize);
- sqlite3_free(pHist->pStmt);
- pHist->pStmt = 0;
- }
- }
- pPager->dbSize = pPager->stmtSize;
- pager_truncate_cache(pPager);
- rc = SQLITE_OK;
- }else{
- rc = pager_stmt_playback(pPager);
- }
- sqlite3PagerStmtCommit(pPager);
- }else{
- rc = SQLITE_OK;
- }
- pPager->stmtAutoopen = 0;
- pagerLeave(pPager);
- return rc;
-}
-
-/*
-** Return the full pathname of the database file.
-*/
-const char *sqlite3PagerFilename(Pager *pPager){
- return pPager->zFilename;
-}
-
-/*
-** Return the VFS structure for the pager.
-*/
-const sqlite3_vfs *sqlite3PagerVfs(Pager *pPager){
- return pPager->pVfs;
-}
-
-/*
-** Return the file handle for the database file associated
-** with the pager. This might return NULL if the file has
-** not yet been opened.
-*/
-sqlite3_file *sqlite3PagerFile(Pager *pPager){
- return pPager->fd;
-}
-
-/*
-** Return the directory of the database file.
-*/
-const char *sqlite3PagerDirname(Pager *pPager){
- return pPager->zDirectory;
-}
-
-/*
-** Return the full pathname of the journal file.
-*/
-const char *sqlite3PagerJournalname(Pager *pPager){
- return pPager->zJournal;
-}
-
-/*
-** Return true if fsync() calls are disabled for this pager. Return FALSE
-** if fsync()s are executed normally.
-*/
-int sqlite3PagerNosync(Pager *pPager){
- return pPager->noSync;
-}
-
-#ifdef SQLITE_HAS_CODEC
-/*
-** Set the codec for this pager
-*/
-void sqlite3PagerSetCodec(
- Pager *pPager,
- void *(*xCodec)(void*,void*,Pgno,int),
- void *pCodecArg
-){
- pPager->xCodec = xCodec;
- pPager->pCodecArg = pCodecArg;
-}
-#endif
-
-#ifndef SQLITE_OMIT_AUTOVACUUM
-/*
-** Move the page pPg to location pgno in the file.
-**
-** There must be no references to the page previously located at
-** pgno (which we call pPgOld) though that page is allowed to be
-** in cache. If the page previous located at pgno is not already
-** in the rollback journal, it is not put there by by this routine.
-**
-** References to the page pPg remain valid. Updating any
-** meta-data associated with pPg (i.e. data stored in the nExtra bytes
-** allocated along with the page) is the responsibility of the caller.
-**
-** A transaction must be active when this routine is called. It used to be
-** required that a statement transaction was not active, but this restriction
-** has been removed (CREATE INDEX needs to move a page when a statement
-** transaction is active).
-*/
-int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno){
- PgHdr *pPgOld; /* The page being overwritten. */
- int h;
- Pgno needSyncPgno = 0;
-
- pagerEnter(pPager);
- assert( pPg->nRef>0 );
-
- PAGERTRACE5("MOVE %d page %d (needSync=%d) moves to %d\n",
- PAGERID(pPager), pPg->pgno, pPg->needSync, pgno);
- IOTRACE(("MOVE %p %d %d\n", pPager, pPg->pgno, pgno))
-
- pager_get_content(pPg);
- if( pPg->needSync ){
- needSyncPgno = pPg->pgno;
- assert( pPg->inJournal || (int)pgno>pPager->origDbSize );
- assert( pPg->dirty );
- assert( pPager->needSync );
- }
-
- /* Unlink pPg from its hash-chain */
- unlinkHashChain(pPager, pPg);
-
- /* If the cache contains a page with page-number pgno, remove it
- ** from its hash chain. Also, if the PgHdr.needSync was set for
- ** page pgno before the 'move' operation, it needs to be retained
- ** for the page moved there.
- */
- pPg->needSync = 0;
- pPgOld = pager_lookup(pPager, pgno);
- if( pPgOld ){
- assert( pPgOld->nRef==0 );
- unlinkHashChain(pPager, pPgOld);
- makeClean(pPgOld);
- pPg->needSync = pPgOld->needSync;
- }else{
- pPg->needSync = 0;
- }
- if( pPager->aInJournal && (int)pgno<=pPager->origDbSize ){
- pPg->inJournal = (pPager->aInJournal[pgno/8] & (1<<(pgno&7)))!=0;
- }else{
- pPg->inJournal = 0;
- assert( pPg->needSync==0 || (int)pgno>pPager->origDbSize );
- }
-
- /* Change the page number for pPg and insert it into the new hash-chain. */
- assert( pgno!=0 );
- pPg->pgno = pgno;
- h = pgno & (pPager->nHash-1);
- if( pPager->aHash[h] ){
- assert( pPager->aHash[h]->pPrevHash==0 );
- pPager->aHash[h]->pPrevHash = pPg;
- }
- pPg->pNextHash = pPager->aHash[h];
- pPager->aHash[h] = pPg;
- pPg->pPrevHash = 0;
-
- makeDirty(pPg);
- pPager->dirtyCache = 1;
-
- if( needSyncPgno ){
- /* If needSyncPgno is non-zero, then the journal file needs to be
- ** sync()ed before any data is written to database file page needSyncPgno.
- ** Currently, no such page exists in the page-cache and the
- ** Pager.aInJournal bit has been set. This needs to be remedied by loading
- ** the page into the pager-cache and setting the PgHdr.needSync flag.
- **
- ** The sqlite3PagerGet() call may cause the journal to sync. So make
- ** sure the Pager.needSync flag is set too.
- */
- int rc;
- PgHdr *pPgHdr;
- assert( pPager->needSync );
- rc = sqlite3PagerGet(pPager, needSyncPgno, &pPgHdr);
- if( rc!=SQLITE_OK ) return rc;
- pPager->needSync = 1;
- pPgHdr->needSync = 1;
- pPgHdr->inJournal = 1;
- makeDirty(pPgHdr);
- sqlite3PagerUnref(pPgHdr);
- }
-
- pagerLeave(pPager);
- return SQLITE_OK;
-}
-#endif
-
-/*
-** Return a pointer to the data for the specified page.
-*/
-void *sqlite3PagerGetData(DbPage *pPg){
- return PGHDR_TO_DATA(pPg);
-}
-
-/*
-** Return a pointer to the Pager.nExtra bytes of "extra" space
-** allocated along with the specified page.
-*/
-void *sqlite3PagerGetExtra(DbPage *pPg){
- Pager *pPager = pPg->pPager;
- return (pPager?PGHDR_TO_EXTRA(pPg, pPager):0);
-}
-
-/*
-** Get/set the locking-mode for this pager. Parameter eMode must be one
-** of PAGER_LOCKINGMODE_QUERY, PAGER_LOCKINGMODE_NORMAL or
-** PAGER_LOCKINGMODE_EXCLUSIVE. If the parameter is not _QUERY, then
-** the locking-mode is set to the value specified.
-**
-** The returned value is either PAGER_LOCKINGMODE_NORMAL or
-** PAGER_LOCKINGMODE_EXCLUSIVE, indicating the current (possibly updated)
-** locking-mode.
-*/
-int sqlite3PagerLockingMode(Pager *pPager, int eMode){
- assert( eMode==PAGER_LOCKINGMODE_QUERY
- || eMode==PAGER_LOCKINGMODE_NORMAL
- || eMode==PAGER_LOCKINGMODE_EXCLUSIVE );
- assert( PAGER_LOCKINGMODE_QUERY<0 );
- assert( PAGER_LOCKINGMODE_NORMAL>=0 && PAGER_LOCKINGMODE_EXCLUSIVE>=0 );
- if( eMode>=0 && !pPager->tempFile ){
- pPager->exclusiveMode = eMode;
- }
- return (int)pPager->exclusiveMode;
-}
-
-#ifdef SQLITE_TEST
-/*
-** Print a listing of all referenced pages and their ref count.
-*/
-void sqlite3PagerRefdump(Pager *pPager){
- PgHdr *pPg;
- for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
- if( pPg->nRef<=0 ) continue;
- sqlite3DebugPrintf("PAGE %3d addr=%p nRef=%d\n",
- pPg->pgno, PGHDR_TO_DATA(pPg), pPg->nRef);
- }
-}
-#endif
-
-#endif /* SQLITE_OMIT_DISKIO */