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Diffstat (limited to 'lib/libsqlite3/src/backup.c')
| -rw-r--r-- | lib/libsqlite3/src/backup.c | 798 |
1 files changed, 0 insertions, 798 deletions
diff --git a/lib/libsqlite3/src/backup.c b/lib/libsqlite3/src/backup.c deleted file mode 100644 index 69e3c528228..00000000000 --- a/lib/libsqlite3/src/backup.c +++ /dev/null @@ -1,798 +0,0 @@ -/* -** 2009 January 28 -** -** 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 file contains the implementation of the sqlite3_backup_XXX() -** API functions and the related features. -*/ -#include "sqliteInt.h" -#include "btreeInt.h" - -/* -** Structure allocated for each backup operation. -*/ -struct sqlite3_backup { - sqlite3* pDestDb; /* Destination database handle */ - Btree *pDest; /* Destination b-tree file */ - u32 iDestSchema; /* Original schema cookie in destination */ - int bDestLocked; /* True once a write-transaction is open on pDest */ - - Pgno iNext; /* Page number of the next source page to copy */ - sqlite3* pSrcDb; /* Source database handle */ - Btree *pSrc; /* Source b-tree file */ - - int rc; /* Backup process error code */ - - /* These two variables are set by every call to backup_step(). They are - ** read by calls to backup_remaining() and backup_pagecount(). - */ - Pgno nRemaining; /* Number of pages left to copy */ - Pgno nPagecount; /* Total number of pages to copy */ - - int isAttached; /* True once backup has been registered with pager */ - sqlite3_backup *pNext; /* Next backup associated with source pager */ -}; - -/* -** THREAD SAFETY NOTES: -** -** Once it has been created using backup_init(), a single sqlite3_backup -** structure may be accessed via two groups of thread-safe entry points: -** -** * Via the sqlite3_backup_XXX() API function backup_step() and -** backup_finish(). Both these functions obtain the source database -** handle mutex and the mutex associated with the source BtShared -** structure, in that order. -** -** * Via the BackupUpdate() and BackupRestart() functions, which are -** invoked by the pager layer to report various state changes in -** the page cache associated with the source database. The mutex -** associated with the source database BtShared structure will always -** be held when either of these functions are invoked. -** -** The other sqlite3_backup_XXX() API functions, backup_remaining() and -** backup_pagecount() are not thread-safe functions. If they are called -** while some other thread is calling backup_step() or backup_finish(), -** the values returned may be invalid. There is no way for a call to -** BackupUpdate() or BackupRestart() to interfere with backup_remaining() -** or backup_pagecount(). -** -** Depending on the SQLite configuration, the database handles and/or -** the Btree objects may have their own mutexes that require locking. -** Non-sharable Btrees (in-memory databases for example), do not have -** associated mutexes. -*/ - -/* -** Return a pointer corresponding to database zDb (i.e. "main", "temp") -** in connection handle pDb. If such a database cannot be found, return -** a NULL pointer and write an error message to pErrorDb. -** -** If the "temp" database is requested, it may need to be opened by this -** function. If an error occurs while doing so, return 0 and write an -** error message to pErrorDb. -*/ -static Btree *findBtree(sqlite3 *pErrorDb, sqlite3 *pDb, const char *zDb){ - int i = sqlite3FindDbName(pDb, zDb); - - if( i==1 ){ - Parse *pParse; - int rc = 0; - pParse = sqlite3StackAllocZero(pErrorDb, sizeof(*pParse)); - if( pParse==0 ){ - sqlite3ErrorWithMsg(pErrorDb, SQLITE_NOMEM, "out of memory"); - rc = SQLITE_NOMEM; - }else{ - pParse->db = pDb; - if( sqlite3OpenTempDatabase(pParse) ){ - sqlite3ErrorWithMsg(pErrorDb, pParse->rc, "%s", pParse->zErrMsg); - rc = SQLITE_ERROR; - } - sqlite3DbFree(pErrorDb, pParse->zErrMsg); - sqlite3ParserReset(pParse); - sqlite3StackFree(pErrorDb, pParse); - } - if( rc ){ - return 0; - } - } - - if( i<0 ){ - sqlite3ErrorWithMsg(pErrorDb, SQLITE_ERROR, "unknown database %s", zDb); - return 0; - } - - return pDb->aDb[i].pBt; -} - -/* -** Attempt to set the page size of the destination to match the page size -** of the source. -*/ -static int setDestPgsz(sqlite3_backup *p){ - int rc; - rc = sqlite3BtreeSetPageSize(p->pDest,sqlite3BtreeGetPageSize(p->pSrc),-1,0); - return rc; -} - -/* -** Check that there is no open read-transaction on the b-tree passed as the -** second argument. If there is not, return SQLITE_OK. Otherwise, if there -** is an open read-transaction, return SQLITE_ERROR and leave an error -** message in database handle db. -*/ -static int checkReadTransaction(sqlite3 *db, Btree *p){ - if( sqlite3BtreeIsInReadTrans(p) ){ - sqlite3ErrorWithMsg(db, SQLITE_ERROR, "destination database is in use"); - return SQLITE_ERROR; - } - return SQLITE_OK; -} - -/* -** Create an sqlite3_backup process to copy the contents of zSrcDb from -** connection handle pSrcDb to zDestDb in pDestDb. If successful, return -** a pointer to the new sqlite3_backup object. -** -** If an error occurs, NULL is returned and an error code and error message -** stored in database handle pDestDb. -*/ -sqlite3_backup *sqlite3_backup_init( - sqlite3* pDestDb, /* Database to write to */ - const char *zDestDb, /* Name of database within pDestDb */ - sqlite3* pSrcDb, /* Database connection to read from */ - const char *zSrcDb /* Name of database within pSrcDb */ -){ - sqlite3_backup *p; /* Value to return */ - -#ifdef SQLITE_ENABLE_API_ARMOR - if( !sqlite3SafetyCheckOk(pSrcDb)||!sqlite3SafetyCheckOk(pDestDb) ){ - (void)SQLITE_MISUSE_BKPT; - return 0; - } -#endif - - /* Lock the source database handle. The destination database - ** handle is not locked in this routine, but it is locked in - ** sqlite3_backup_step(). The user is required to ensure that no - ** other thread accesses the destination handle for the duration - ** of the backup operation. Any attempt to use the destination - ** database connection while a backup is in progress may cause - ** a malfunction or a deadlock. - */ - sqlite3_mutex_enter(pSrcDb->mutex); - sqlite3_mutex_enter(pDestDb->mutex); - - if( pSrcDb==pDestDb ){ - sqlite3ErrorWithMsg( - pDestDb, SQLITE_ERROR, "source and destination must be distinct" - ); - p = 0; - }else { - /* Allocate space for a new sqlite3_backup object... - ** EVIDENCE-OF: R-64852-21591 The sqlite3_backup object is created by a - ** call to sqlite3_backup_init() and is destroyed by a call to - ** sqlite3_backup_finish(). */ - p = (sqlite3_backup *)sqlite3MallocZero(sizeof(sqlite3_backup)); - if( !p ){ - sqlite3Error(pDestDb, SQLITE_NOMEM); - } - } - - /* If the allocation succeeded, populate the new object. */ - if( p ){ - p->pSrc = findBtree(pDestDb, pSrcDb, zSrcDb); - p->pDest = findBtree(pDestDb, pDestDb, zDestDb); - p->pDestDb = pDestDb; - p->pSrcDb = pSrcDb; - p->iNext = 1; - p->isAttached = 0; - - if( 0==p->pSrc || 0==p->pDest - || setDestPgsz(p)==SQLITE_NOMEM - || checkReadTransaction(pDestDb, p->pDest)!=SQLITE_OK - ){ - /* One (or both) of the named databases did not exist or an OOM - ** error was hit. Or there is a transaction open on the destination - ** database. The error has already been written into the pDestDb - ** handle. All that is left to do here is free the sqlite3_backup - ** structure. */ - sqlite3_free(p); - p = 0; - } - } - if( p ){ - p->pSrc->nBackup++; - } - - sqlite3_mutex_leave(pDestDb->mutex); - sqlite3_mutex_leave(pSrcDb->mutex); - return p; -} - -/* -** Argument rc is an SQLite error code. Return true if this error is -** considered fatal if encountered during a backup operation. All errors -** are considered fatal except for SQLITE_BUSY and SQLITE_LOCKED. -*/ -static int isFatalError(int rc){ - return (rc!=SQLITE_OK && rc!=SQLITE_BUSY && ALWAYS(rc!=SQLITE_LOCKED)); -} - -/* -** Parameter zSrcData points to a buffer containing the data for -** page iSrcPg from the source database. Copy this data into the -** destination database. -*/ -static int backupOnePage( - sqlite3_backup *p, /* Backup handle */ - Pgno iSrcPg, /* Source database page to backup */ - const u8 *zSrcData, /* Source database page data */ - int bUpdate /* True for an update, false otherwise */ -){ - Pager * const pDestPager = sqlite3BtreePager(p->pDest); - const int nSrcPgsz = sqlite3BtreeGetPageSize(p->pSrc); - int nDestPgsz = sqlite3BtreeGetPageSize(p->pDest); - const int nCopy = MIN(nSrcPgsz, nDestPgsz); - const i64 iEnd = (i64)iSrcPg*(i64)nSrcPgsz; -#ifdef SQLITE_HAS_CODEC - /* Use BtreeGetReserveNoMutex() for the source b-tree, as although it is - ** guaranteed that the shared-mutex is held by this thread, handle - ** p->pSrc may not actually be the owner. */ - int nSrcReserve = sqlite3BtreeGetReserveNoMutex(p->pSrc); - int nDestReserve = sqlite3BtreeGetOptimalReserve(p->pDest); -#endif - int rc = SQLITE_OK; - i64 iOff; - - assert( sqlite3BtreeGetReserveNoMutex(p->pSrc)>=0 ); - assert( p->bDestLocked ); - assert( !isFatalError(p->rc) ); - assert( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) ); - assert( zSrcData ); - - /* Catch the case where the destination is an in-memory database and the - ** page sizes of the source and destination differ. - */ - if( nSrcPgsz!=nDestPgsz && sqlite3PagerIsMemdb(pDestPager) ){ - rc = SQLITE_READONLY; - } - -#ifdef SQLITE_HAS_CODEC - /* Backup is not possible if the page size of the destination is changing - ** and a codec is in use. - */ - if( nSrcPgsz!=nDestPgsz && sqlite3PagerGetCodec(pDestPager)!=0 ){ - rc = SQLITE_READONLY; - } - - /* Backup is not possible if the number of bytes of reserve space differ - ** between source and destination. If there is a difference, try to - ** fix the destination to agree with the source. If that is not possible, - ** then the backup cannot proceed. - */ - if( nSrcReserve!=nDestReserve ){ - u32 newPgsz = nSrcPgsz; - rc = sqlite3PagerSetPagesize(pDestPager, &newPgsz, nSrcReserve); - if( rc==SQLITE_OK && newPgsz!=nSrcPgsz ) rc = SQLITE_READONLY; - } -#endif - - /* This loop runs once for each destination page spanned by the source - ** page. For each iteration, variable iOff is set to the byte offset - ** of the destination page. - */ - for(iOff=iEnd-(i64)nSrcPgsz; rc==SQLITE_OK && iOff<iEnd; iOff+=nDestPgsz){ - DbPage *pDestPg = 0; - Pgno iDest = (Pgno)(iOff/nDestPgsz)+1; - if( iDest==PENDING_BYTE_PAGE(p->pDest->pBt) ) continue; - if( SQLITE_OK==(rc = sqlite3PagerGet(pDestPager, iDest, &pDestPg)) - && SQLITE_OK==(rc = sqlite3PagerWrite(pDestPg)) - ){ - const u8 *zIn = &zSrcData[iOff%nSrcPgsz]; - u8 *zDestData = sqlite3PagerGetData(pDestPg); - u8 *zOut = &zDestData[iOff%nDestPgsz]; - - /* Copy the data from the source page into the destination page. - ** Then clear the Btree layer MemPage.isInit flag. Both this module - ** and the pager code use this trick (clearing the first byte - ** of the page 'extra' space to invalidate the Btree layers - ** cached parse of the page). MemPage.isInit is marked - ** "MUST BE FIRST" for this purpose. - */ - memcpy(zOut, zIn, nCopy); - ((u8 *)sqlite3PagerGetExtra(pDestPg))[0] = 0; - if( iOff==0 && bUpdate==0 ){ - sqlite3Put4byte(&zOut[28], sqlite3BtreeLastPage(p->pSrc)); - } - } - sqlite3PagerUnref(pDestPg); - } - - return rc; -} - -/* -** If pFile is currently larger than iSize bytes, then truncate it to -** exactly iSize bytes. If pFile is not larger than iSize bytes, then -** this function is a no-op. -** -** Return SQLITE_OK if everything is successful, or an SQLite error -** code if an error occurs. -*/ -static int backupTruncateFile(sqlite3_file *pFile, i64 iSize){ - i64 iCurrent; - int rc = sqlite3OsFileSize(pFile, &iCurrent); - if( rc==SQLITE_OK && iCurrent>iSize ){ - rc = sqlite3OsTruncate(pFile, iSize); - } - return rc; -} - -/* -** Register this backup object with the associated source pager for -** callbacks when pages are changed or the cache invalidated. -*/ -static void attachBackupObject(sqlite3_backup *p){ - sqlite3_backup **pp; - assert( sqlite3BtreeHoldsMutex(p->pSrc) ); - pp = sqlite3PagerBackupPtr(sqlite3BtreePager(p->pSrc)); - p->pNext = *pp; - *pp = p; - p->isAttached = 1; -} - -/* -** Copy nPage pages from the source b-tree to the destination. -*/ -int sqlite3_backup_step(sqlite3_backup *p, int nPage){ - int rc; - int destMode; /* Destination journal mode */ - int pgszSrc = 0; /* Source page size */ - int pgszDest = 0; /* Destination page size */ - -#ifdef SQLITE_ENABLE_API_ARMOR - if( p==0 ) return SQLITE_MISUSE_BKPT; -#endif - sqlite3_mutex_enter(p->pSrcDb->mutex); - sqlite3BtreeEnter(p->pSrc); - if( p->pDestDb ){ - sqlite3_mutex_enter(p->pDestDb->mutex); - } - - rc = p->rc; - if( !isFatalError(rc) ){ - Pager * const pSrcPager = sqlite3BtreePager(p->pSrc); /* Source pager */ - Pager * const pDestPager = sqlite3BtreePager(p->pDest); /* Dest pager */ - int ii; /* Iterator variable */ - int nSrcPage = -1; /* Size of source db in pages */ - int bCloseTrans = 0; /* True if src db requires unlocking */ - - /* If the source pager is currently in a write-transaction, return - ** SQLITE_BUSY immediately. - */ - if( p->pDestDb && p->pSrc->pBt->inTransaction==TRANS_WRITE ){ - rc = SQLITE_BUSY; - }else{ - rc = SQLITE_OK; - } - - /* Lock the destination database, if it is not locked already. */ - if( SQLITE_OK==rc && p->bDestLocked==0 - && SQLITE_OK==(rc = sqlite3BtreeBeginTrans(p->pDest, 2)) - ){ - p->bDestLocked = 1; - sqlite3BtreeGetMeta(p->pDest, BTREE_SCHEMA_VERSION, &p->iDestSchema); - } - - /* If there is no open read-transaction on the source database, open - ** one now. If a transaction is opened here, then it will be closed - ** before this function exits. - */ - if( rc==SQLITE_OK && 0==sqlite3BtreeIsInReadTrans(p->pSrc) ){ - rc = sqlite3BtreeBeginTrans(p->pSrc, 0); - bCloseTrans = 1; - } - - /* Do not allow backup if the destination database is in WAL mode - ** and the page sizes are different between source and destination */ - pgszSrc = sqlite3BtreeGetPageSize(p->pSrc); - pgszDest = sqlite3BtreeGetPageSize(p->pDest); - destMode = sqlite3PagerGetJournalMode(sqlite3BtreePager(p->pDest)); - if( SQLITE_OK==rc && destMode==PAGER_JOURNALMODE_WAL && pgszSrc!=pgszDest ){ - rc = SQLITE_READONLY; - } - - /* Now that there is a read-lock on the source database, query the - ** source pager for the number of pages in the database. - */ - nSrcPage = (int)sqlite3BtreeLastPage(p->pSrc); - assert( nSrcPage>=0 ); - for(ii=0; (nPage<0 || ii<nPage) && p->iNext<=(Pgno)nSrcPage && !rc; ii++){ - const Pgno iSrcPg = p->iNext; /* Source page number */ - if( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) ){ - DbPage *pSrcPg; /* Source page object */ - rc = sqlite3PagerAcquire(pSrcPager, iSrcPg, &pSrcPg, - PAGER_GET_READONLY); - if( rc==SQLITE_OK ){ - rc = backupOnePage(p, iSrcPg, sqlite3PagerGetData(pSrcPg), 0); - sqlite3PagerUnref(pSrcPg); - } - } - p->iNext++; - } - if( rc==SQLITE_OK ){ - p->nPagecount = nSrcPage; - p->nRemaining = nSrcPage+1-p->iNext; - if( p->iNext>(Pgno)nSrcPage ){ - rc = SQLITE_DONE; - }else if( !p->isAttached ){ - attachBackupObject(p); - } - } - - /* Update the schema version field in the destination database. This - ** is to make sure that the schema-version really does change in - ** the case where the source and destination databases have the - ** same schema version. - */ - if( rc==SQLITE_DONE ){ - if( nSrcPage==0 ){ - rc = sqlite3BtreeNewDb(p->pDest); - nSrcPage = 1; - } - if( rc==SQLITE_OK || rc==SQLITE_DONE ){ - rc = sqlite3BtreeUpdateMeta(p->pDest,1,p->iDestSchema+1); - } - if( rc==SQLITE_OK ){ - if( p->pDestDb ){ - sqlite3ResetAllSchemasOfConnection(p->pDestDb); - } - if( destMode==PAGER_JOURNALMODE_WAL ){ - rc = sqlite3BtreeSetVersion(p->pDest, 2); - } - } - if( rc==SQLITE_OK ){ - int nDestTruncate; - /* Set nDestTruncate to the final number of pages in the destination - ** database. The complication here is that the destination page - ** size may be different to the source page size. - ** - ** If the source page size is smaller than the destination page size, - ** round up. In this case the call to sqlite3OsTruncate() below will - ** fix the size of the file. However it is important to call - ** sqlite3PagerTruncateImage() here so that any pages in the - ** destination file that lie beyond the nDestTruncate page mark are - ** journalled by PagerCommitPhaseOne() before they are destroyed - ** by the file truncation. - */ - assert( pgszSrc==sqlite3BtreeGetPageSize(p->pSrc) ); - assert( pgszDest==sqlite3BtreeGetPageSize(p->pDest) ); - if( pgszSrc<pgszDest ){ - int ratio = pgszDest/pgszSrc; - nDestTruncate = (nSrcPage+ratio-1)/ratio; - if( nDestTruncate==(int)PENDING_BYTE_PAGE(p->pDest->pBt) ){ - nDestTruncate--; - } - }else{ - nDestTruncate = nSrcPage * (pgszSrc/pgszDest); - } - assert( nDestTruncate>0 ); - - if( pgszSrc<pgszDest ){ - /* If the source page-size is smaller than the destination page-size, - ** two extra things may need to happen: - ** - ** * The destination may need to be truncated, and - ** - ** * Data stored on the pages immediately following the - ** pending-byte page in the source database may need to be - ** copied into the destination database. - */ - const i64 iSize = (i64)pgszSrc * (i64)nSrcPage; - sqlite3_file * const pFile = sqlite3PagerFile(pDestPager); - Pgno iPg; - int nDstPage; - i64 iOff; - i64 iEnd; - - assert( pFile ); - assert( nDestTruncate==0 - || (i64)nDestTruncate*(i64)pgszDest >= iSize || ( - nDestTruncate==(int)(PENDING_BYTE_PAGE(p->pDest->pBt)-1) - && iSize>=PENDING_BYTE && iSize<=PENDING_BYTE+pgszDest - )); - - /* This block ensures that all data required to recreate the original - ** database has been stored in the journal for pDestPager and the - ** journal synced to disk. So at this point we may safely modify - ** the database file in any way, knowing that if a power failure - ** occurs, the original database will be reconstructed from the - ** journal file. */ - sqlite3PagerPagecount(pDestPager, &nDstPage); - for(iPg=nDestTruncate; rc==SQLITE_OK && iPg<=(Pgno)nDstPage; iPg++){ - if( iPg!=PENDING_BYTE_PAGE(p->pDest->pBt) ){ - DbPage *pPg; - rc = sqlite3PagerGet(pDestPager, iPg, &pPg); - if( rc==SQLITE_OK ){ - rc = sqlite3PagerWrite(pPg); - sqlite3PagerUnref(pPg); - } - } - } - if( rc==SQLITE_OK ){ - rc = sqlite3PagerCommitPhaseOne(pDestPager, 0, 1); - } - - /* Write the extra pages and truncate the database file as required */ - iEnd = MIN(PENDING_BYTE + pgszDest, iSize); - for( - iOff=PENDING_BYTE+pgszSrc; - rc==SQLITE_OK && iOff<iEnd; - iOff+=pgszSrc - ){ - PgHdr *pSrcPg = 0; - const Pgno iSrcPg = (Pgno)((iOff/pgszSrc)+1); - rc = sqlite3PagerGet(pSrcPager, iSrcPg, &pSrcPg); - if( rc==SQLITE_OK ){ - u8 *zData = sqlite3PagerGetData(pSrcPg); - rc = sqlite3OsWrite(pFile, zData, pgszSrc, iOff); - } - sqlite3PagerUnref(pSrcPg); - } - if( rc==SQLITE_OK ){ - rc = backupTruncateFile(pFile, iSize); - } - - /* Sync the database file to disk. */ - if( rc==SQLITE_OK ){ - rc = sqlite3PagerSync(pDestPager, 0); - } - }else{ - sqlite3PagerTruncateImage(pDestPager, nDestTruncate); - rc = sqlite3PagerCommitPhaseOne(pDestPager, 0, 0); - } - - /* Finish committing the transaction to the destination database. */ - if( SQLITE_OK==rc - && SQLITE_OK==(rc = sqlite3BtreeCommitPhaseTwo(p->pDest, 0)) - ){ - rc = SQLITE_DONE; - } - } - } - - /* If bCloseTrans is true, then this function opened a read transaction - ** on the source database. Close the read transaction here. There is - ** no need to check the return values of the btree methods here, as - ** "committing" a read-only transaction cannot fail. - */ - if( bCloseTrans ){ - TESTONLY( int rc2 ); - TESTONLY( rc2 = ) sqlite3BtreeCommitPhaseOne(p->pSrc, 0); - TESTONLY( rc2 |= ) sqlite3BtreeCommitPhaseTwo(p->pSrc, 0); - assert( rc2==SQLITE_OK ); - } - - if( rc==SQLITE_IOERR_NOMEM ){ - rc = SQLITE_NOMEM; - } - p->rc = rc; - } - if( p->pDestDb ){ - sqlite3_mutex_leave(p->pDestDb->mutex); - } - sqlite3BtreeLeave(p->pSrc); - sqlite3_mutex_leave(p->pSrcDb->mutex); - return rc; -} - -/* -** Release all resources associated with an sqlite3_backup* handle. -*/ -int sqlite3_backup_finish(sqlite3_backup *p){ - sqlite3_backup **pp; /* Ptr to head of pagers backup list */ - sqlite3 *pSrcDb; /* Source database connection */ - int rc; /* Value to return */ - - /* Enter the mutexes */ - if( p==0 ) return SQLITE_OK; - pSrcDb = p->pSrcDb; - sqlite3_mutex_enter(pSrcDb->mutex); - sqlite3BtreeEnter(p->pSrc); - if( p->pDestDb ){ - sqlite3_mutex_enter(p->pDestDb->mutex); - } - - /* Detach this backup from the source pager. */ - if( p->pDestDb ){ - p->pSrc->nBackup--; - } - if( p->isAttached ){ - pp = sqlite3PagerBackupPtr(sqlite3BtreePager(p->pSrc)); - while( *pp!=p ){ - pp = &(*pp)->pNext; - } - *pp = p->pNext; - } - - /* If a transaction is still open on the Btree, roll it back. */ - sqlite3BtreeRollback(p->pDest, SQLITE_OK, 0); - - /* Set the error code of the destination database handle. */ - rc = (p->rc==SQLITE_DONE) ? SQLITE_OK : p->rc; - if( p->pDestDb ){ - sqlite3Error(p->pDestDb, rc); - - /* Exit the mutexes and free the backup context structure. */ - sqlite3LeaveMutexAndCloseZombie(p->pDestDb); - } - sqlite3BtreeLeave(p->pSrc); - if( p->pDestDb ){ - /* EVIDENCE-OF: R-64852-21591 The sqlite3_backup object is created by a - ** call to sqlite3_backup_init() and is destroyed by a call to - ** sqlite3_backup_finish(). */ - sqlite3_free(p); - } - sqlite3LeaveMutexAndCloseZombie(pSrcDb); - return rc; -} - -/* -** Return the number of pages still to be backed up as of the most recent -** call to sqlite3_backup_step(). -*/ -int sqlite3_backup_remaining(sqlite3_backup *p){ -#ifdef SQLITE_ENABLE_API_ARMOR - if( p==0 ){ - (void)SQLITE_MISUSE_BKPT; - return 0; - } -#endif - return p->nRemaining; -} - -/* -** Return the total number of pages in the source database as of the most -** recent call to sqlite3_backup_step(). -*/ -int sqlite3_backup_pagecount(sqlite3_backup *p){ -#ifdef SQLITE_ENABLE_API_ARMOR - if( p==0 ){ - (void)SQLITE_MISUSE_BKPT; - return 0; - } -#endif - return p->nPagecount; -} - -/* -** This function is called after the contents of page iPage of the -** source database have been modified. If page iPage has already been -** copied into the destination database, then the data written to the -** destination is now invalidated. The destination copy of iPage needs -** to be updated with the new data before the backup operation is -** complete. -** -** It is assumed that the mutex associated with the BtShared object -** corresponding to the source database is held when this function is -** called. -*/ -static SQLITE_NOINLINE void backupUpdate( - sqlite3_backup *p, - Pgno iPage, - const u8 *aData -){ - assert( p!=0 ); - do{ - assert( sqlite3_mutex_held(p->pSrc->pBt->mutex) ); - if( !isFatalError(p->rc) && iPage<p->iNext ){ - /* The backup process p has already copied page iPage. But now it - ** has been modified by a transaction on the source pager. Copy - ** the new data into the backup. - */ - int rc; - assert( p->pDestDb ); - sqlite3_mutex_enter(p->pDestDb->mutex); - rc = backupOnePage(p, iPage, aData, 1); - sqlite3_mutex_leave(p->pDestDb->mutex); - assert( rc!=SQLITE_BUSY && rc!=SQLITE_LOCKED ); - if( rc!=SQLITE_OK ){ - p->rc = rc; - } - } - }while( (p = p->pNext)!=0 ); -} -void sqlite3BackupUpdate(sqlite3_backup *pBackup, Pgno iPage, const u8 *aData){ - if( pBackup ) backupUpdate(pBackup, iPage, aData); -} - -/* -** Restart the backup process. This is called when the pager layer -** detects that the database has been modified by an external database -** connection. In this case there is no way of knowing which of the -** pages that have been copied into the destination database are still -** valid and which are not, so the entire process needs to be restarted. -** -** It is assumed that the mutex associated with the BtShared object -** corresponding to the source database is held when this function is -** called. -*/ -void sqlite3BackupRestart(sqlite3_backup *pBackup){ - sqlite3_backup *p; /* Iterator variable */ - for(p=pBackup; p; p=p->pNext){ - assert( sqlite3_mutex_held(p->pSrc->pBt->mutex) ); - p->iNext = 1; - } -} - -#ifndef SQLITE_OMIT_VACUUM -/* -** Copy the complete content of pBtFrom into pBtTo. A transaction -** must be active for both files. -** -** The size of file pTo may be reduced by this operation. If anything -** goes wrong, the transaction on pTo is rolled back. If successful, the -** transaction is committed before returning. -*/ -int sqlite3BtreeCopyFile(Btree *pTo, Btree *pFrom){ - int rc; - sqlite3_file *pFd; /* File descriptor for database pTo */ - sqlite3_backup b; - sqlite3BtreeEnter(pTo); - sqlite3BtreeEnter(pFrom); - - assert( sqlite3BtreeIsInTrans(pTo) ); - pFd = sqlite3PagerFile(sqlite3BtreePager(pTo)); - if( pFd->pMethods ){ - i64 nByte = sqlite3BtreeGetPageSize(pFrom)*(i64)sqlite3BtreeLastPage(pFrom); - rc = sqlite3OsFileControl(pFd, SQLITE_FCNTL_OVERWRITE, &nByte); - if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK; - if( rc ) goto copy_finished; - } - - /* Set up an sqlite3_backup object. sqlite3_backup.pDestDb must be set - ** to 0. This is used by the implementations of sqlite3_backup_step() - ** and sqlite3_backup_finish() to detect that they are being called - ** from this function, not directly by the user. - */ - memset(&b, 0, sizeof(b)); - b.pSrcDb = pFrom->db; - b.pSrc = pFrom; - b.pDest = pTo; - b.iNext = 1; - -#ifdef SQLITE_HAS_CODEC - sqlite3PagerAlignReserve(sqlite3BtreePager(pTo), sqlite3BtreePager(pFrom)); -#endif - - /* 0x7FFFFFFF is the hard limit for the number of pages in a database - ** file. By passing this as the number of pages to copy to - ** sqlite3_backup_step(), we can guarantee that the copy finishes - ** within a single call (unless an error occurs). The assert() statement - ** checks this assumption - (p->rc) should be set to either SQLITE_DONE - ** or an error code. - */ - sqlite3_backup_step(&b, 0x7FFFFFFF); - assert( b.rc!=SQLITE_OK ); - rc = sqlite3_backup_finish(&b); - if( rc==SQLITE_OK ){ - pTo->pBt->btsFlags &= ~BTS_PAGESIZE_FIXED; - }else{ - sqlite3PagerClearCache(sqlite3BtreePager(b.pDest)); - } - - assert( sqlite3BtreeIsInTrans(pTo)==0 ); -copy_finished: - sqlite3BtreeLeave(pFrom); - sqlite3BtreeLeave(pTo); - return rc; -} -#endif /* SQLITE_OMIT_VACUUM */ |