diff -r 5f8e5adbbed9 -r 29cda98b007e engine/sqlite/src/btreeInt.h --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/engine/sqlite/src/btreeInt.h Thu Feb 25 14:29:19 2010 +0000 @@ -0,0 +1,649 @@ +/* +** 2004 April 6 +** +** 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. +** +************************************************************************* +** $Id: btreeInt.h 1282 2008-11-13 09:31:33Z LarsPson $ +** +** This file implements a external (disk-based) database using BTrees. +** For a detailed discussion of BTrees, refer to +** +** Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3: +** "Sorting And Searching", pages 473-480. Addison-Wesley +** Publishing Company, Reading, Massachusetts. +** +** The basic idea is that each page of the file contains N database +** entries and N+1 pointers to subpages. +** +** ---------------------------------------------------------------- +** | Ptr(0) | Key(0) | Ptr(1) | Key(1) | ... | Key(N-1) | Ptr(N) | +** ---------------------------------------------------------------- +** +** All of the keys on the page that Ptr(0) points to have values less +** than Key(0). All of the keys on page Ptr(1) and its subpages have +** values greater than Key(0) and less than Key(1). All of the keys +** on Ptr(N) and its subpages have values greater than Key(N-1). And +** so forth. +** +** Finding a particular key requires reading O(log(M)) pages from the +** disk where M is the number of entries in the tree. +** +** In this implementation, a single file can hold one or more separate +** BTrees. Each BTree is identified by the index of its root page. The +** key and data for any entry are combined to form the "payload". A +** fixed amount of payload can be carried directly on the database +** page. If the payload is larger than the preset amount then surplus +** bytes are stored on overflow pages. The payload for an entry +** and the preceding pointer are combined to form a "Cell". Each +** page has a small header which contains the Ptr(N) pointer and other +** information such as the size of key and data. +** +** FORMAT DETAILS +** +** The file is divided into pages. The first page is called page 1, +** the second is page 2, and so forth. A page number of zero indicates +** "no such page". The page size can be anything between 512 and 65536. +** Each page can be either a btree page, a freelist page or an overflow +** page. +** +** The first page is always a btree page. The first 100 bytes of the first +** page contain a special header (the "file header") that describes the file. +** The format of the file header is as follows: +** +** OFFSET SIZE DESCRIPTION +** 0 16 Header string: "SQLite format 3\000" +** 16 2 Page size in bytes. +** 18 1 File format write version +** 19 1 File format read version +** 20 1 Bytes of unused space at the end of each page +** 21 1 Max embedded payload fraction +** 22 1 Min embedded payload fraction +** 23 1 Min leaf payload fraction +** 24 4 File change counter +** 28 4 Reserved for future use +** 32 4 First freelist page +** 36 4 Number of freelist pages in the file +** 40 60 15 4-byte meta values passed to higher layers +** +** All of the integer values are big-endian (most significant byte first). +** +** The file change counter is incremented when the database is changed +** This counter allows other processes to know when the file has changed +** and thus when they need to flush their cache. +** +** The max embedded payload fraction is the amount of the total usable +** space in a page that can be consumed by a single cell for standard +** B-tree (non-LEAFDATA) tables. A value of 255 means 100%. The default +** is to limit the maximum cell size so that at least 4 cells will fit +** on one page. Thus the default max embedded payload fraction is 64. +** +** If the payload for a cell is larger than the max payload, then extra +** payload is spilled to overflow pages. Once an overflow page is allocated, +** as many bytes as possible are moved into the overflow pages without letting +** the cell size drop below the min embedded payload fraction. +** +** The min leaf payload fraction is like the min embedded payload fraction +** except that it applies to leaf nodes in a LEAFDATA tree. The maximum +** payload fraction for a LEAFDATA tree is always 100% (or 255) and it +** not specified in the header. +** +** Each btree pages is divided into three sections: The header, the +** cell pointer array, and the cell content area. Page 1 also has a 100-byte +** file header that occurs before the page header. +** +** |----------------| +** | file header | 100 bytes. Page 1 only. +** |----------------| +** | page header | 8 bytes for leaves. 12 bytes for interior nodes +** |----------------| +** | cell pointer | | 2 bytes per cell. Sorted order. +** | array | | Grows downward +** | | v +** |----------------| +** | unallocated | +** | space | +** |----------------| ^ Grows upwards +** | cell content | | Arbitrary order interspersed with freeblocks. +** | area | | and free space fragments. +** |----------------| +** +** The page headers looks like this: +** +** OFFSET SIZE DESCRIPTION +** 0 1 Flags. 1: intkey, 2: zerodata, 4: leafdata, 8: leaf +** 1 2 byte offset to the first freeblock +** 3 2 number of cells on this page +** 5 2 first byte of the cell content area +** 7 1 number of fragmented free bytes +** 8 4 Right child (the Ptr(N) value). Omitted on leaves. +** +** The flags define the format of this btree page. The leaf flag means that +** this page has no children. The zerodata flag means that this page carries +** only keys and no data. The intkey flag means that the key is a integer +** which is stored in the key size entry of the cell header rather than in +** the payload area. +** +** The cell pointer array begins on the first byte after the page header. +** The cell pointer array contains zero or more 2-byte numbers which are +** offsets from the beginning of the page to the cell content in the cell +** content area. The cell pointers occur in sorted order. The system strives +** to keep free space after the last cell pointer so that new cells can +** be easily added without having to defragment the page. +** +** Cell content is stored at the very end of the page and grows toward the +** beginning of the page. +** +** Unused space within the cell content area is collected into a linked list of +** freeblocks. Each freeblock is at least 4 bytes in size. The byte offset +** to the first freeblock is given in the header. Freeblocks occur in +** increasing order. Because a freeblock must be at least 4 bytes in size, +** any group of 3 or fewer unused bytes in the cell content area cannot +** exist on the freeblock chain. A group of 3 or fewer free bytes is called +** a fragment. The total number of bytes in all fragments is recorded. +** in the page header at offset 7. +** +** SIZE DESCRIPTION +** 2 Byte offset of the next freeblock +** 2 Bytes in this freeblock +** +** Cells are of variable length. Cells are stored in the cell content area at +** the end of the page. Pointers to the cells are in the cell pointer array +** that immediately follows the page header. Cells is not necessarily +** contiguous or in order, but cell pointers are contiguous and in order. +** +** Cell content makes use of variable length integers. A variable +** length integer is 1 to 9 bytes where the lower 7 bits of each +** byte are used. The integer consists of all bytes that have bit 8 set and +** the first byte with bit 8 clear. The most significant byte of the integer +** appears first. A variable-length integer may not be more than 9 bytes long. +** As a special case, all 8 bytes of the 9th byte are used as data. This +** allows a 64-bit integer to be encoded in 9 bytes. +** +** 0x00 becomes 0x00000000 +** 0x7f becomes 0x0000007f +** 0x81 0x00 becomes 0x00000080 +** 0x82 0x00 becomes 0x00000100 +** 0x80 0x7f becomes 0x0000007f +** 0x8a 0x91 0xd1 0xac 0x78 becomes 0x12345678 +** 0x81 0x81 0x81 0x81 0x01 becomes 0x10204081 +** +** Variable length integers are used for rowids and to hold the number of +** bytes of key and data in a btree cell. +** +** The content of a cell looks like this: +** +** SIZE DESCRIPTION +** 4 Page number of the left child. Omitted if leaf flag is set. +** var Number of bytes of data. Omitted if the zerodata flag is set. +** var Number of bytes of key. Or the key itself if intkey flag is set. +** * Payload +** 4 First page of the overflow chain. Omitted if no overflow +** +** Overflow pages form a linked list. Each page except the last is completely +** filled with data (pagesize - 4 bytes). The last page can have as little +** as 1 byte of data. +** +** SIZE DESCRIPTION +** 4 Page number of next overflow page +** * Data +** +** Freelist pages come in two subtypes: trunk pages and leaf pages. The +** file header points to the first in a linked list of trunk page. Each trunk +** page points to multiple leaf pages. The content of a leaf page is +** unspecified. A trunk page looks like this: +** +** SIZE DESCRIPTION +** 4 Page number of next trunk page +** 4 Number of leaf pointers on this page +** * zero or more pages numbers of leaves +*/ +#include "sqliteInt.h" +#include "pager.h" +#include "btree.h" +#include "os.h" +#include + +/* Round up a number to the next larger multiple of 8. This is used +** to force 8-byte alignment on 64-bit architectures. +*/ +#define ROUND8(x) ((x+7)&~7) + + +/* The following value is the maximum cell size assuming a maximum page +** size give above. +*/ +#define MX_CELL_SIZE(pBt) (pBt->pageSize-8) + +/* The maximum number of cells on a single page of the database. This +** assumes a minimum cell size of 3 bytes. Such small cells will be +** exceedingly rare, but they are possible. +*/ +#define MX_CELL(pBt) ((pBt->pageSize-8)/3) + +/* Forward declarations */ +typedef struct MemPage MemPage; +typedef struct BtLock BtLock; + +/* +** This is a magic string that appears at the beginning of every +** SQLite database in order to identify the file as a real database. +** +** You can change this value at compile-time by specifying a +** -DSQLITE_FILE_HEADER="..." on the compiler command-line. The +** header must be exactly 16 bytes including the zero-terminator so +** the string itself should be 15 characters long. If you change +** the header, then your custom library will not be able to read +** databases generated by the standard tools and the standard tools +** will not be able to read databases created by your custom library. +*/ +#ifndef SQLITE_FILE_HEADER /* 123456789 123456 */ +# define SQLITE_FILE_HEADER "SQLite format 3" +#endif + +/* +** Page type flags. An ORed combination of these flags appear as the +** first byte of on-disk image of every BTree page. +*/ +#define PTF_INTKEY 0x01 +#define PTF_ZERODATA 0x02 +#define PTF_LEAFDATA 0x04 +#define PTF_LEAF 0x08 + +/* +** As each page of the file is loaded into memory, an instance of the following +** structure is appended and initialized to zero. This structure stores +** information about the page that is decoded from the raw file page. +** +** The pParent field points back to the parent page. This allows us to +** walk up the BTree from any leaf to the root. Care must be taken to +** unref() the parent page pointer when this page is no longer referenced. +** The pageDestructor() routine handles that chore. +** +** Access to all fields of this structure is controlled by the mutex +** stored in MemPage.pBt->mutex. +*/ +struct MemPage { + u8 isInit; /* True if previously initialized. MUST BE FIRST! */ + u8 idxShift; /* True if Cell indices have changed */ + u8 nOverflow; /* Number of overflow cell bodies in aCell[] */ + u8 intKey; /* True if intkey flag is set */ + u8 leaf; /* True if leaf flag is set */ + u8 zeroData; /* True if table stores keys only */ + u8 leafData; /* True if tables stores data on leaves only */ + u8 hasData; /* True if this page stores data */ + u8 hdrOffset; /* 100 for page 1. 0 otherwise */ + u8 childPtrSize; /* 0 if leaf==1. 4 if leaf==0 */ + u16 maxLocal; /* Copy of BtShared.maxLocal or BtShared.maxLeaf */ + u16 minLocal; /* Copy of BtShared.minLocal or BtShared.minLeaf */ + u16 cellOffset; /* Index in aData of first cell pointer */ + u16 idxParent; /* Index in parent of this node */ + u16 nFree; /* Number of free bytes on the page */ + u16 nCell; /* Number of cells on this page, local and ovfl */ + struct _OvflCell { /* Cells that will not fit on aData[] */ + u8 *pCell; /* Pointers to the body of the overflow cell */ + u16 idx; /* Insert this cell before idx-th non-overflow cell */ + } aOvfl[5]; + BtShared *pBt; /* Pointer to BtShared that this page is part of */ + u8 *aData; /* Pointer to disk image of the page data */ + DbPage *pDbPage; /* Pager page handle */ + Pgno pgno; /* Page number for this page */ + MemPage *pParent; /* The parent of this page. NULL for root */ +}; + +/* +** The in-memory image of a disk page has the auxiliary information appended +** to the end. EXTRA_SIZE is the number of bytes of space needed to hold +** that extra information. +*/ +#define EXTRA_SIZE sizeof(MemPage) + +/* A Btree handle +** +** A database connection contains a pointer to an instance of +** this object for every database file that it has open. This structure +** is opaque to the database connection. The database connection cannot +** see the internals of this structure and only deals with pointers to +** this structure. +** +** For some database files, the same underlying database cache might be +** shared between multiple connections. In that case, each contection +** has it own pointer to this object. But each instance of this object +** points to the same BtShared object. The database cache and the +** schema associated with the database file are all contained within +** the BtShared object. +** +** All fields in this structure are accessed under sqlite3.mutex. +** The pBt pointer itself may not be changed while there exists cursors +** in the referenced BtShared that point back to this Btree since those +** cursors have to do go through this Btree to find their BtShared and +** they often do so without holding sqlite3.mutex. +*/ +struct Btree { + sqlite3 *db; /* The database connection holding this btree */ + BtShared *pBt; /* Sharable content of this btree */ + u8 inTrans; /* TRANS_NONE, TRANS_READ or TRANS_WRITE */ + u8 sharable; /* True if we can share pBt with another db */ + u8 locked; /* True if db currently has pBt locked */ + int wantToLock; /* Number of nested calls to sqlite3BtreeEnter() */ + Btree *pNext; /* List of other sharable Btrees from the same db */ + Btree *pPrev; /* Back pointer of the same list */ +}; + +/* +** Btree.inTrans may take one of the following values. +** +** If the shared-data extension is enabled, there may be multiple users +** of the Btree structure. At most one of these may open a write transaction, +** but any number may have active read transactions. +*/ +#define TRANS_NONE 0 +#define TRANS_READ 1 +#define TRANS_WRITE 2 + +/* +** An instance of this object represents a single database file. +** +** A single database file can be in use as the same time by two +** or more database connections. When two or more connections are +** sharing the same database file, each connection has it own +** private Btree object for the file and each of those Btrees points +** to this one BtShared object. BtShared.nRef is the number of +** connections currently sharing this database file. +** +** Fields in this structure are accessed under the BtShared.mutex +** mutex, except for nRef and pNext which are accessed under the +** global SQLITE_MUTEX_STATIC_MASTER mutex. The pPager field +** may not be modified once it is initially set as long as nRef>0. +** The pSchema field may be set once under BtShared.mutex and +** thereafter is unchanged as long as nRef>0. +*/ +struct BtShared { + Pager *pPager; /* The page cache */ + sqlite3 *db; /* Database connection currently using this Btree */ + BtCursor *pCursor; /* A list of all open cursors */ + MemPage *pPage1; /* First page of the database */ + u8 inStmt; /* True if we are in a statement subtransaction */ + u8 readOnly; /* True if the underlying file is readonly */ + u8 maxEmbedFrac; /* Maximum payload as % of total page size */ + u8 minEmbedFrac; /* Minimum payload as % of total page size */ + u8 minLeafFrac; /* Minimum leaf payload as % of total page size */ + u8 pageSizeFixed; /* True if the page size can no longer be changed */ +#ifndef SQLITE_OMIT_AUTOVACUUM + u8 autoVacuum; /* True if auto-vacuum is enabled */ + u8 incrVacuum; /* True if incr-vacuum is enabled */ + Pgno nTrunc; /* Non-zero if the db will be truncated (incr vacuum) */ +#endif + u16 pageSize; /* Total number of bytes on a page */ + u16 usableSize; /* Number of usable bytes on each page */ + int maxLocal; /* Maximum local payload in non-LEAFDATA tables */ + int minLocal; /* Minimum local payload in non-LEAFDATA tables */ + int maxLeaf; /* Maximum local payload in a LEAFDATA table */ + int minLeaf; /* Minimum local payload in a LEAFDATA table */ + u8 inTransaction; /* Transaction state */ + int nTransaction; /* Number of open transactions (read + write) */ + void *pSchema; /* Pointer to space allocated by sqlite3BtreeSchema() */ + void (*xFreeSchema)(void*); /* Destructor for BtShared.pSchema */ + sqlite3_mutex *mutex; /* Non-recursive mutex required to access this struct */ + BusyHandler busyHdr; /* The busy handler for this btree */ +#ifndef SQLITE_OMIT_SHARED_CACHE + int nRef; /* Number of references to this structure */ + BtShared *pNext; /* Next on a list of sharable BtShared structs */ + BtLock *pLock; /* List of locks held on this shared-btree struct */ +#endif +}; + +/* +** An instance of the following structure is used to hold information +** about a cell. The parseCellPtr() function fills in this structure +** based on information extract from the raw disk page. +*/ +typedef struct CellInfo CellInfo; +struct CellInfo { + u8 *pCell; /* Pointer to the start of cell content */ + i64 nKey; /* The key for INTKEY tables, or number of bytes in key */ + u32 nData; /* Number of bytes of data */ + u32 nPayload; /* Total amount of payload */ + u16 nHeader; /* Size of the cell content header in bytes */ + u16 nLocal; /* Amount of payload held locally */ + u16 iOverflow; /* Offset to overflow page number. Zero if no overflow */ + u16 nSize; /* Size of the cell content on the main b-tree page */ +}; + +/* +** A cursor is a pointer to a particular entry within a particular +** b-tree within a database file. +** +** The entry is identified by its MemPage and the index in +** MemPage.aCell[] of the entry. +** +** When a single database file can shared by two more database connections, +** but cursors cannot be shared. Each cursor is associated with a +** particular database connection identified BtCursor.pBtree.db. +** +** Fields in this structure are accessed under the BtShared.mutex +** found at self->pBt->mutex. +*/ +struct BtCursor { + Btree *pBtree; /* The Btree to which this cursor belongs */ + BtShared *pBt; /* The BtShared this cursor points to */ + BtCursor *pNext, *pPrev; /* Forms a linked list of all cursors */ + int (*xCompare)(void*,int,const void*,int,const void*); /* Key comp func */ + void *pArg; /* First arg to xCompare() */ + Pgno pgnoRoot; /* The root page of this tree */ + MemPage *pPage; /* Page that contains the entry */ + int idx; /* Index of the entry in pPage->aCell[] */ + CellInfo info; /* A parse of the cell we are pointing at */ + u8 wrFlag; /* True if writable */ + u8 eState; /* One of the CURSOR_XXX constants (see below) */ + void *pKey; /* Saved key that was cursor's last known position */ + i64 nKey; /* Size of pKey, or last integer key */ + int skip; /* (skip<0) -> Prev() is a no-op. (skip>0) -> Next() is */ +#ifndef SQLITE_OMIT_INCRBLOB + u8 isIncrblobHandle; /* True if this cursor is an incr. io handle */ + Pgno *aOverflow; /* Cache of overflow page locations */ +#endif +}; + +/* +** Potential values for BtCursor.eState. +** +** CURSOR_VALID: +** Cursor points to a valid entry. getPayload() etc. may be called. +** +** CURSOR_INVALID: +** Cursor does not point to a valid entry. This can happen (for example) +** because the table is empty or because BtreeCursorFirst() has not been +** called. +** +** CURSOR_REQUIRESEEK: +** The table that this cursor was opened on still exists, but has been +** modified since the cursor was last used. The cursor position is saved +** in variables BtCursor.pKey and BtCursor.nKey. When a cursor is in +** this state, restoreOrClearCursorPosition() can be called to attempt to +** seek the cursor to the saved position. +** +** CURSOR_FAULT: +** A unrecoverable error (an I/O error or a malloc failure) has occurred +** on a different connection that shares the BtShared cache with this +** cursor. The error has left the cache in an inconsistent state. +** Do nothing else with this cursor. Any attempt to use the cursor +** should return the error code stored in BtCursor.skip +*/ +#define CURSOR_INVALID 0 +#define CURSOR_VALID 1 +#define CURSOR_REQUIRESEEK 2 +#define CURSOR_FAULT 3 + +/* +** The TRACE macro will print high-level status information about the +** btree operation when the global variable sqlite3_btree_trace is +** enabled. +*/ +#if SQLITE_TEST +# define TRACE(X) if( sqlite3_btree_trace ){ printf X; fflush(stdout); } +#else +# define TRACE(X) +#endif + +/* +** Routines to read and write variable-length integers. These used to +** be defined locally, but now we use the varint routines in the util.c +** file. +*/ +#define getVarint sqlite3GetVarint +#define getVarint32(A,B) ((*B=*(A))<=0x7f?1:sqlite3GetVarint32(A,B)) +#define putVarint sqlite3PutVarint + +/* The database page the PENDING_BYTE occupies. This page is never used. +** TODO: This macro is very similary to PAGER_MJ_PGNO() in pager.c. They +** should possibly be consolidated (presumably in pager.h). +** +** If disk I/O is omitted (meaning that the database is stored purely +** in memory) then there is no pending byte. +*/ +#ifdef SQLITE_OMIT_DISKIO +# define PENDING_BYTE_PAGE(pBt) 0x7fffffff +#else +# define PENDING_BYTE_PAGE(pBt) ((PENDING_BYTE/(pBt)->pageSize)+1) +#endif + +/* +** A linked list of the following structures is stored at BtShared.pLock. +** Locks are added (or upgraded from READ_LOCK to WRITE_LOCK) when a cursor +** is opened on the table with root page BtShared.iTable. Locks are removed +** from this list when a transaction is committed or rolled back, or when +** a btree handle is closed. +*/ +struct BtLock { + Btree *pBtree; /* Btree handle holding this lock */ + Pgno iTable; /* Root page of table */ + u8 eLock; /* READ_LOCK or WRITE_LOCK */ + BtLock *pNext; /* Next in BtShared.pLock list */ +}; + +/* Candidate values for BtLock.eLock */ +#define READ_LOCK 1 +#define WRITE_LOCK 2 + +/* +** These macros define the location of the pointer-map entry for a +** database page. The first argument to each is the number of usable +** bytes on each page of the database (often 1024). The second is the +** page number to look up in the pointer map. +** +** PTRMAP_PAGENO returns the database page number of the pointer-map +** page that stores the required pointer. PTRMAP_PTROFFSET returns +** the offset of the requested map entry. +** +** If the pgno argument passed to PTRMAP_PAGENO is a pointer-map page, +** then pgno is returned. So (pgno==PTRMAP_PAGENO(pgsz, pgno)) can be +** used to test if pgno is a pointer-map page. PTRMAP_ISPAGE implements +** this test. +*/ +#define PTRMAP_PAGENO(pBt, pgno) ptrmapPageno(pBt, pgno) +#define PTRMAP_PTROFFSET(pBt, pgno) (5*(pgno-ptrmapPageno(pBt, pgno)-1)) +#define PTRMAP_ISPAGE(pBt, pgno) (PTRMAP_PAGENO((pBt),(pgno))==(pgno)) + +/* +** The pointer map is a lookup table that identifies the parent page for +** each child page in the database file. The parent page is the page that +** contains a pointer to the child. Every page in the database contains +** 0 or 1 parent pages. (In this context 'database page' refers +** to any page that is not part of the pointer map itself.) Each pointer map +** entry consists of a single byte 'type' and a 4 byte parent page number. +** The PTRMAP_XXX identifiers below are the valid types. +** +** The purpose of the pointer map is to facility moving pages from one +** position in the file to another as part of autovacuum. When a page +** is moved, the pointer in its parent must be updated to point to the +** new location. The pointer map is used to locate the parent page quickly. +** +** PTRMAP_ROOTPAGE: The database page is a root-page. The page-number is not +** used in this case. +** +** PTRMAP_FREEPAGE: The database page is an unused (free) page. The page-number +** is not used in this case. +** +** PTRMAP_OVERFLOW1: The database page is the first page in a list of +** overflow pages. The page number identifies the page that +** contains the cell with a pointer to this overflow page. +** +** PTRMAP_OVERFLOW2: The database page is the second or later page in a list of +** overflow pages. The page-number identifies the previous +** page in the overflow page list. +** +** PTRMAP_BTREE: The database page is a non-root btree page. The page number +** identifies the parent page in the btree. +*/ +#define PTRMAP_ROOTPAGE 1 +#define PTRMAP_FREEPAGE 2 +#define PTRMAP_OVERFLOW1 3 +#define PTRMAP_OVERFLOW2 4 +#define PTRMAP_BTREE 5 + +/* A bunch of assert() statements to check the transaction state variables +** of handle p (type Btree*) are internally consistent. +*/ +#define btreeIntegrity(p) \ + assert( p->pBt->inTransaction!=TRANS_NONE || p->pBt->nTransaction==0 ); \ + assert( p->pBt->inTransaction>=p->inTrans ); + + +/* +** The ISAUTOVACUUM macro is used within balance_nonroot() to determine +** if the database supports auto-vacuum or not. Because it is used +** within an expression that is an argument to another macro +** (sqliteMallocRaw), it is not possible to use conditional compilation. +** So, this macro is defined instead. +*/ +#ifndef SQLITE_OMIT_AUTOVACUUM +#define ISAUTOVACUUM (pBt->autoVacuum) +#else +#define ISAUTOVACUUM 0 +#endif + + +/* +** This structure is passed around through all the sanity checking routines +** in order to keep track of some global state information. +*/ +typedef struct IntegrityCk IntegrityCk; +struct IntegrityCk { + BtShared *pBt; /* The tree being checked out */ + Pager *pPager; /* The associated pager. Also accessible by pBt->pPager */ + int nPage; /* Number of pages in the database */ + int *anRef; /* Number of times each page is referenced */ + int mxErr; /* Stop accumulating errors when this reaches zero */ + char *zErrMsg; /* An error message. NULL if no errors seen. */ + int nErr; /* Number of messages written to zErrMsg so far */ +}; + +/* +** Read or write a two- and four-byte big-endian integer values. +*/ +#define get2byte(x) ((x)[0]<<8 | (x)[1]) +#define put2byte(p,v) ((p)[0] = (v)>>8, (p)[1] = (v)) +#define get4byte sqlite3Get4byte +#define put4byte sqlite3Put4byte + +/* +** Internal routines that should be accessed by the btree layer only. +*/ +int sqlite3BtreeGetPage(BtShared*, Pgno, MemPage**, int); +int sqlite3BtreeInitPage(MemPage *pPage, MemPage *pParent); +void sqlite3BtreeParseCellPtr(MemPage*, u8*, CellInfo*); +void sqlite3BtreeParseCell(MemPage*, int, CellInfo*); +#ifdef SQLITE_TEST +u8 *sqlite3BtreeFindCell(MemPage *pPage, int iCell); +#endif +int sqlite3BtreeRestoreOrClearCursorPosition(BtCursor *pCur); +void sqlite3BtreeGetTempCursor(BtCursor *pCur, BtCursor *pTempCur); +void sqlite3BtreeReleaseTempCursor(BtCursor *pCur); +int sqlite3BtreeIsRootPage(MemPage *pPage); +void sqlite3BtreeMoveToParent(BtCursor *pCur);