From 2f8d7092bc2c9609fa98d6888106b96f38b22828 Mon Sep 17 00:00:00 2001 From: dan miller Date: Sun, 21 Oct 2007 08:36:32 +0000 Subject: libraries moved to opensim-libs, a new repository --- libraries/sqlite/win32/pager.c | 5104 ---------------------------------------- 1 file changed, 5104 deletions(-) delete mode 100755 libraries/sqlite/win32/pager.c (limited to 'libraries/sqlite/win32/pager.c') diff --git a/libraries/sqlite/win32/pager.c b/libraries/sqlite/win32/pager.c deleted file mode 100755 index b0ad715..0000000 --- a/libraries/sqlite/win32/pager.c +++ /dev/null @@ -1,5104 +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.c,v 1.392 2007/10/03 15:22:26 danielk1977 Exp $ -*/ -#ifndef SQLITE_OMIT_DISKIO -#include "sqliteInt.h" -#include -#include - -/* -** 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 it's argument. The -** associated file-descriptor is returned. FILEHANDLEID() takes an sqlite3_file -** struct as it's 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 it's 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 = 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->pMethods ){ - 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; ipPager->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; ijournalOff; - 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)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; ifullSync ){ - 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->pData); - 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->pMethods ){ - 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->statestmtOpen && !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)state>=PAGER_EXCLUSIVE && pPager->fd->pMethods ){ - rc = sqlite3OsTruncate(pPager->fd, pPager->pageSize*(i64)nPage); - } - 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->sectorSizepageSize ){ - 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 it's 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; ijfd, 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; ipageSize); - 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; -} - -/* -** 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 = 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 = 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 = sqlite3OsOpen(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( nDefaultPagefd); - 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; -} - -/* -** 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->pMethods ){ - 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->pMethods) - && (rc = sqlite3OsFileSize(pPager->fd, &n))!=SQLITE_OK ){ - pPager->nRef++; - pager_error(pPager, rc); - pPager->nRef--; - return 0; - } - if( n>0 && npageSize ){ - 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 it's 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->pData); - 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->pgnopgno ){ - 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; ipPager; - - /* 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->pMethods ){ - 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( !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 */ - 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 || nReleasedneedSync || 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); - - rc = pager_recycle(pPager, &pRecycled); - 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->pData); - 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->pMethods ){ - 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 it's own EXCLUSIVE lock on the database file. - */ - if( pPager->statefd, 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; - void *pData; - - /* Create a new PgHdr if any of the four conditions defined - ** above are met: */ - if( pPager->nPagemxPage - || 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); - pPg = sqlite3_malloc( sizeof(*pPg) + sizeof(u32) + pPager->nExtra - + MEMDB*sizeof(PgHistory) ); - if( pPg ){ - pData = sqlite3_malloc( pPager->pageSize ); - if( pData==0 ){ - sqlite3_free(pPg); - pPg = 0; - } - } - pagerEnter(pPager); - if( pPg==0 ){ - rc = SQLITE_NOMEM; - goto pager_allocate_out; - } - memset(pPg, 0, sizeof(*pPg)); - if( MEMDB ){ - memset(PGHDR_TO_HIST(pPg, pPager), 0, sizeof(PgHistory)); - } - pPg->pData = pData; - 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 = 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 = 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 = sqlite3_malloc( pPager->pageSize ); - if( pHist->pOrig ){ - 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 = 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; iiaInJournal || 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; iineedSync = 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->origDbSizedbSize ){ - /* 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->pMethods ){ - 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's - * 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->statedirty = 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 = 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 it's hash-chain */ - unlinkHashChain(pPager, pPg); - - /* If the cache contains a page with page-number pgno, remove it - ** from it's 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_DEBUG -/* -** 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 */ -- cgit v1.1