diff -r 4a65cc85c4f3 -r fbd95db6a4e1 engine/sqlite/src/journal.cpp --- a/engine/sqlite/src/journal.cpp Wed Apr 28 13:20:05 2010 +0100 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,238 +0,0 @@ -/* -** 2007 August 22 -** -** 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: journal.cpp 1282 2008-11-13 09:31:33Z LarsPson $ -*/ - -#ifdef SQLITE_ENABLE_ATOMIC_WRITE - -/* -** This file implements a special kind of sqlite3_file object used -** by SQLite to create journal files if the atomic-write optimization -** is enabled. -** -** The distinctive characteristic of this sqlite3_file is that the -** actual on disk file is created lazily. When the file is created, -** the caller specifies a buffer size for an in-memory buffer to -** be used to service read() and write() requests. The actual file -** on disk is not created or populated until either: -** -** 1) The in-memory representation grows too large for the allocated -** buffer, or -** 2) The xSync() method is called. -*/ - -#include "sqliteInt.h" - - -/* -** A JournalFile object is a subclass of sqlite3_file used by -** as an open file handle for journal files. -*/ -struct JournalFile { - sqlite3_io_methods *pMethod; /* I/O methods on journal files */ - int nBuf; /* Size of zBuf[] in bytes */ - char *zBuf; /* Space to buffer journal writes */ - int iSize; /* Amount of zBuf[] currently used */ - int flags; /* xOpen flags */ - sqlite3_vfs *pVfs; /* The "real" underlying VFS */ - sqlite3_file *pReal; /* The "real" underlying file descriptor */ - const char *zJournal; /* Name of the journal file */ -}; -typedef struct JournalFile JournalFile; - -/* -** If it does not already exists, create and populate the on-disk file -** for JournalFile p. -*/ -static int createFile(JournalFile *p){ - int rc = SQLITE_OK; - if( !p->pReal ){ - sqlite3_file *pReal = (sqlite3_file *)&p[1]; - rc = sqlite3OsOpen(p->pVfs, p->zJournal, pReal, p->flags, 0); - if( rc==SQLITE_OK ){ - p->pReal = pReal; - if( p->iSize>0 ){ - assert(p->iSize<=p->nBuf); - rc = sqlite3OsWrite(p->pReal, p->zBuf, p->iSize, 0); - } - } - } - return rc; -} - -/* -** Close the file. -*/ -static int jrnlClose(sqlite3_file *pJfd){ - JournalFile *p = (JournalFile *)pJfd; - if( p->pReal ){ - sqlite3OsClose(p->pReal); - } - sqlite3_free(p->zBuf); - return SQLITE_OK; -} - -/* -** Read data from the file. -*/ -static int jrnlRead( - sqlite3_file *pJfd, /* The journal file from which to read */ - void *zBuf, /* Put the results here */ - int iAmt, /* Number of bytes to read */ - sqlite_int64 iOfst /* Begin reading at this offset */ -){ - int rc = SQLITE_OK; - JournalFile *p = (JournalFile *)pJfd; - if( p->pReal ){ - rc = sqlite3OsRead(p->pReal, zBuf, iAmt, iOfst); - }else{ - assert( iAmt+iOfst<=p->iSize ); - memcpy(zBuf, &p->zBuf[iOfst], iAmt); - } - return rc; -} - -/* -** Write data to the file. -*/ -static int jrnlWrite( - sqlite3_file *pJfd, /* The journal file into which to write */ - const void *zBuf, /* Take data to be written from here */ - int iAmt, /* Number of bytes to write */ - sqlite_int64 iOfst /* Begin writing at this offset into the file */ -){ - int rc = SQLITE_OK; - JournalFile *p = (JournalFile *)pJfd; - if( !p->pReal && (iOfst+iAmt)>p->nBuf ){ - rc = createFile(p); - } - if( rc==SQLITE_OK ){ - if( p->pReal ){ - rc = sqlite3OsWrite(p->pReal, zBuf, iAmt, iOfst); - }else{ - memcpy(&p->zBuf[iOfst], zBuf, iAmt); - if( p->iSize<(iOfst+iAmt) ){ - p->iSize = (iOfst+iAmt); - } - } - } - return rc; -} - -/* -** Truncate the file. -*/ -static int jrnlTruncate(sqlite3_file *pJfd, sqlite_int64 size){ - int rc = SQLITE_OK; - JournalFile *p = (JournalFile *)pJfd; - if( p->pReal ){ - rc = sqlite3OsTruncate(p->pReal, size); - }else if( sizeiSize ){ - p->iSize = size; - } - return rc; -} - -/* -** Sync the file. -*/ -static int jrnlSync(sqlite3_file *pJfd, int flags){ - int rc; - JournalFile *p = (JournalFile *)pJfd; - rc = createFile(p); - if( rc==SQLITE_OK ){ - rc = sqlite3OsSync(p->pReal, flags); - } - return rc; -} - -/* -** Query the size of the file in bytes. -*/ -static int jrnlFileSize(sqlite3_file *pJfd, sqlite_int64 *pSize){ - int rc = SQLITE_OK; - JournalFile *p = (JournalFile *)pJfd; - if( p->pReal ){ - rc = sqlite3OsFileSize(p->pReal, pSize); - }else{ - *pSize = (sqlite_int64) p->iSize; - } - return rc; -} - -/* -** Table of methods for JournalFile sqlite3_file object. -*/ -static struct sqlite3_io_methods JournalFileMethods = { - 1, /* iVersion */ - jrnlClose, /* xClose */ - jrnlRead, /* xRead */ - jrnlWrite, /* xWrite */ - jrnlTruncate, /* xTruncate */ - jrnlSync, /* xSync */ - jrnlFileSize, /* xFileSize */ - 0, /* xLock */ - 0, /* xUnlock */ - 0, /* xCheckReservedLock */ - 0, /* xFileControl */ - 0, /* xSectorSize */ - 0 /* xDeviceCharacteristics */ -}; - -/* -** Open a journal file. -*/ -int sqlite3JournalOpen( - sqlite3_vfs *pVfs, /* The VFS to use for actual file I/O */ - const char *zName, /* Name of the journal file */ - sqlite3_file *pJfd, /* Preallocated, blank file handle */ - int flags, /* Opening flags */ - int nBuf /* Bytes buffered before opening the file */ -){ - JournalFile *p = (JournalFile *)pJfd; - memset(p, 0, sqlite3JournalSize(pVfs)); - if( nBuf>0 ){ - p->zBuf = sqlite3MallocZero(nBuf); - if( !p->zBuf ){ - return SQLITE_NOMEM; - } - }else{ - return sqlite3OsOpen(pVfs, zName, pJfd, flags, 0); - } - p->pMethod = &JournalFileMethods; - p->nBuf = nBuf; - p->flags = flags; - p->zJournal = zName; - p->pVfs = pVfs; - return SQLITE_OK; -} - -/* -** If the argument p points to a JournalFile structure, and the underlying -** file has not yet been created, create it now. -*/ -int sqlite3JournalCreate(sqlite3_file *p){ - if( p->pMethods!=&JournalFileMethods ){ - return SQLITE_OK; - } - return createFile((JournalFile *)p); -} - -/* -** Return the number of bytes required to store a JournalFile that uses vfs -** pVfs to create the underlying on-disk files. -*/ -int sqlite3JournalSize(sqlite3_vfs *pVfs){ - return (pVfs->szOsFile+sizeof(JournalFile)); -} -#endif