diff options
Diffstat (limited to 'kopete/plugins/statistics/sqlite/pager.c')
| -rw-r--r-- | kopete/plugins/statistics/sqlite/pager.c | 3205 |
1 files changed, 0 insertions, 3205 deletions
diff --git a/kopete/plugins/statistics/sqlite/pager.c b/kopete/plugins/statistics/sqlite/pager.c deleted file mode 100644 index a374562b..00000000 --- a/kopete/plugins/statistics/sqlite/pager.c +++ /dev/null @@ -1,3205 +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. -** -** @(#) $Id$ -*/ -#include "sqliteInt.h" -#include "os.h" -#include "pager.h" -#include <assert.h> -#include <string.h> - -/* -** Macros for troubleshooting. Normally turned off -*/ -#if 0 -#define TRACE1(X) sqlite3DebugPrintf(X) -#define TRACE2(X,Y) sqlite3DebugPrintf(X,Y) -#define TRACE3(X,Y,Z) sqlite3DebugPrintf(X,Y,Z) -#define TRACE4(X,Y,Z,W) sqlite3DebugPrintf(X,Y,Z,W) -#else -#define TRACE1(X) -#define TRACE2(X,Y) -#define TRACE3(X,Y,Z) -#define TRACE4(X,Y,Z,W) -#endif - - -/* -** 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 the -** journal file and the transaction will be -** committed. -** -** The page cache comes up in PAGER_UNLOCK. The first time a -** sqlite3pager_get() 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 sqlite3pager_write() is called, the state transitions to -** PAGER_RESERVED. (Note that sqlite_page_write() can only be -** called on an outstanding page which means that the pager must -** be in PAGER_SHARED before it transitions to PAGER_RESERVED.) -** The transition to PAGER_EXCLUSIVE occurs when before any changes -** are made to the database file. After an sqlite3pager_rollback() -** or sqlite_pager_commit(), the state goes back to PAGER_SHARED. -*/ -#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 - -/* -** 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 sqlite3pager_write() on a page prior to making -** any modifications to that page. The first time sqlite3pager_write() -** 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 sqlite3pager_write() is called and -** is cleared again when the page content is written back to the original -** database file. -*/ -typedef struct PgHdr PgHdr; -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 */ - PgHdr *pNextFree, *pPrevFree; /* Freelist of pages where nRef==0 */ - PgHdr *pNextAll; /* A list of all pages */ - PgHdr *pNextStmt, *pPrevStmt; /* List of pages in the statement journal */ - u8 inJournal; /* TRUE if has been written to journal */ - u8 inStmt; /* TRUE if in the statement subjournal */ - u8 dirty; /* TRUE if we need to write back changes */ - u8 needSync; /* Sync journal before writing this page */ - u8 alwaysRollback; /* Disable dont_rollback() for this page */ - short int nRef; /* Number of users of this page */ - PgHdr *pDirty; /* Dirty pages sorted by PgHdr.pgno */ - /* pPager->pageSize bytes of page data follow this header */ - /* Pager.nExtra bytes of local data follow the page data */ -}; - -/* -** 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 */ -}; - -/* -** A macro used for invoking the codec if there is one -*/ -#ifdef SQLITE_HAS_CODEC -# define CODEC(P,D,N,X) if( P->xCodec ){ P->xCodec(P->pCodecArg,D,N,X); } -#else -# define CODEC(P,D,N,X) -#endif - -/* -** Convert a pointer to a PgHdr into a pointer to its data -** and back again. -*/ -#define PGHDR_TO_DATA(P) ((void*)(&(P)[1])) -#define DATA_TO_PGHDR(D) (&((PgHdr*)(D))[-1]) -#define PGHDR_TO_EXTRA(G,P) ((void*)&((char*)(&(G)[1]))[(P)->pageSize]) -#define PGHDR_TO_HIST(P,PGR) \ - ((PgHistory*)&((char*)(&(P)[1]))[(PGR)->pageSize+(PGR)->nExtra]) - -/* -** How big to make the hash table used for locating in-memory pages -** by page number. -*/ -#define N_PG_HASH 2048 - -/* -** Hash a page number -*/ -#define pager_hash(PN) ((PN)&(N_PG_HASH-1)) - -/* -** A open page cache is an instance of the following structure. -*/ -struct Pager { - char *zFilename; /* Name of the database file */ - char *zJournal; /* Name of the journal file */ - char *zDirectory; /* Directory hold database and journal files */ - OsFile fd, jfd; /* File descriptors for database and journal */ - OsFile stfd; /* File descriptor for the statement subjournal*/ - 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() */ - i64 stmtJSize; /* Size of journal 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 */ - void (*xDestructor)(void*,int); /* Call this routine when freeing pages */ - void (*xReiniter)(void*,int); /* Call this routine when reloading pages */ - 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 */ - int nHit, nMiss, nOvfl; /* Cache hits, missing, and LRU overflows */ - void (*xCodec)(void*,void*,Pgno,int); /* Routine for en/decoding data */ - void *pCodecArg; /* First argument to xCodec() */ - 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 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 state; /* PAGER_UNLOCK, _SHARED, _RESERVED, etc. */ - u8 errMask; /* One of several kinds of errors */ - 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 dont_rollback() for all pages */ - u8 memDb; /* True to inhibit all file I/O */ - u8 *aInJournal; /* One bit for each page in the database file */ - u8 *aInStmt; /* One bit for each page in the database */ - u8 setMaster; /* True if a m-j name has been written to jrnl */ - BusyHandler *pBusyHandler; /* Pointer to sqlite.busyHandler */ - PgHdr *pFirst, *pLast; /* List of free pages */ - PgHdr *pFirstSynced; /* First free page with PgHdr.needSync==0 */ - PgHdr *pAll; /* List of all pages */ - PgHdr *pStmt; /* List of pages in the statement subjournal */ - 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 */ - int sectorSize; /* Assumed sector size during rollback */ - PgHdr *aHash[N_PG_HASH]; /* Hash table to map page number to PgHdr */ -}; - -/* -** These are bits that can be set in Pager.errMask. -*/ -#define PAGER_ERR_FULL 0x01 /* a write() failed */ -#define PAGER_ERR_MEM 0x02 /* malloc() failed */ -#define PAGER_ERR_LOCK 0x04 /* error in the locking protocol */ -#define PAGER_ERR_CORRUPT 0x08 /* database or journal corruption */ -#define PAGER_ERR_DISK 0x10 /* general disk I/O error - bad hard drive? */ - -/* -** 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) - -#define PAGER_SECTOR_SIZE 512 - -/* -** 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)) - -/* -** Enable reference count tracking (for debugging) here: -*/ -#ifdef SQLITE_TEST - 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=%d\n", - p->pgno, PGHDR_TO_DATA(p), p->nRef - ); - cnt++; /* Something to set a breakpoint on */ - } -# define REFINFO(X) pager_refinfo(X) -#else -# define REFINFO(X) -#endif - -/* -** 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(OsFile *fd, u32 *pRes){ - u32 res; - int rc; - rc = sqlite3OsRead(fd, &res, sizeof(res)); - if( rc==SQLITE_OK ){ - unsigned char ac[4]; - memcpy(ac, &res, 4); - res = (ac[0]<<24) | (ac[1]<<16) | (ac[2]<<8) | ac[3]; - } - *pRes = res; - return rc; -} - -/* -** 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(OsFile *fd, u32 val){ - unsigned char ac[4]; - ac[0] = (val>>24) & 0xff; - ac[1] = (val>>16) & 0xff; - ac[2] = (val>>8) & 0xff; - ac[3] = val & 0xff; - return sqlite3OsWrite(fd, ac, 4); -} - -/* -** Write the 32-bit integer 'val' into the page identified by page header -** 'p' at offset 'offset'. -*/ -static void store32bits(u32 val, PgHdr *p, int offset){ - unsigned char *ac; - ac = &((unsigned char*)PGHDR_TO_DATA(p))[offset]; - ac[0] = (val>>24) & 0xff; - ac[1] = (val>>16) & 0xff; - ac[2] = (val>>8) & 0xff; - ac[3] = val & 0xff; -} - -/* -** Read a 32-bit integer at offset 'offset' from the page identified by -** page header 'p'. -*/ -static u32 retrieve32bits(PgHdr *p, int offset){ - unsigned char *ac; - ac = &((unsigned char*)PGHDR_TO_DATA(p))[offset]; - return (ac[0]<<24) | (ac[1]<<16) | (ac[2]<<8) | ac[3]; -} - - -/* -** Convert the bits in the pPager->errMask into an approprate -** return code. -*/ -static int pager_errcode(Pager *pPager){ - int rc = SQLITE_OK; - if( pPager->errMask & PAGER_ERR_LOCK ) rc = SQLITE_PROTOCOL; - if( pPager->errMask & PAGER_ERR_DISK ) rc = SQLITE_IOERR; - if( pPager->errMask & PAGER_ERR_FULL ) rc = SQLITE_FULL; - if( pPager->errMask & PAGER_ERR_MEM ) rc = SQLITE_NOMEM; - if( pPager->errMask & PAGER_ERR_CORRUPT ) rc = SQLITE_CORRUPT; - return rc; -} - -/* -** 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 obtained from sqliteMalloc(). *pzMaster is -** set to point at the memory and SQLITE_OK returned. The caller must -** sqliteFree() *pzMaster. -** -** If no master journal file name is present *pzMaster is set to 0 and -** SQLITE_OK returned. -*/ -static int readMasterJournal(OsFile *pJrnl, char **pzMaster){ - int rc; - u32 len; - i64 szJ; - u32 cksum; - int i; - unsigned char aMagic[8]; /* A buffer to hold the magic header */ - - *pzMaster = 0; - - rc = sqlite3OsFileSize(pJrnl, &szJ); - if( rc!=SQLITE_OK || szJ<16 ) return rc; - - rc = sqlite3OsSeek(pJrnl, szJ-16); - if( rc!=SQLITE_OK ) return rc; - - rc = read32bits(pJrnl, &len); - if( rc!=SQLITE_OK ) return rc; - - rc = read32bits(pJrnl, &cksum); - if( rc!=SQLITE_OK ) return rc; - - rc = sqlite3OsRead(pJrnl, aMagic, 8); - if( rc!=SQLITE_OK || memcmp(aMagic, aJournalMagic, 8) ) return rc; - - rc = sqlite3OsSeek(pJrnl, szJ-16-len); - if( rc!=SQLITE_OK ) return rc; - - *pzMaster = (char *)sqliteMalloc(len+1); - if( !*pzMaster ){ - return SQLITE_NOMEM; - } - rc = sqlite3OsRead(pJrnl, *pzMaster, len); - if( rc!=SQLITE_OK ){ - sqliteFree(*pzMaster); - *pzMaster = 0; - return rc; - } - - /* See if the checksum matches the master journal name */ - for(i=0; i<len; i++){ - cksum -= (*pzMaster)[i]; - } - if( cksum ){ - /* If the checksum doesn't add up, then one or more of the disk sectors - ** containing the master journal filename is corrupted. This means - ** definitely roll back, so just return SQLITE_OK and report a (nul) - ** master-journal filename. - */ - sqliteFree(*pzMaster); - *pzMaster = 0; - } - (*pzMaster)[len] = '\0'; - - return SQLITE_OK; -} - -/* -** Seek the journal file descriptor to the next sector boundary where a -** journal header may be read or written. Pager.journalOff is updated with -** the new seek offset. -** -** i.e for a sector size of 512: -** -** Input Offset Output Offset -** --------------------------------------- -** 0 0 -** 512 512 -** 100 512 -** 2000 2048 -** -*/ -static int seekJournalHdr(Pager *pPager){ - i64 offset = 0; - i64 c = pPager->journalOff; - if( c ){ - offset = ((c-1)/JOURNAL_HDR_SZ(pPager) + 1) * JOURNAL_HDR_SZ(pPager); - } - assert( offset%JOURNAL_HDR_SZ(pPager)==0 ); - assert( offset>=c ); - assert( (offset-c)<JOURNAL_HDR_SZ(pPager) ); - pPager->journalOff = offset; - return sqlite3OsSeek(&pPager->jfd, pPager->journalOff); -} - -/* -** 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){ - - int rc = seekJournalHdr(pPager); - if( rc ) return rc; - - pPager->journalHdr = pPager->journalOff; - if( pPager->stmtHdrOff==0 ){ - pPager->stmtHdrOff = pPager->journalHdr; - } - pPager->journalOff += JOURNAL_HDR_SZ(pPager); - - /* FIX ME: - ** - ** Possibly for a pager not in no-sync mode, the journal magic should not - ** be written until nRec is filled in as part of next syncJournal(). - ** - ** Actually maybe the whole journal header should be delayed until that - ** point. Think about this. - */ - rc = sqlite3OsWrite(&pPager->jfd, aJournalMagic, sizeof(aJournalMagic)); - - if( rc==SQLITE_OK ){ - /* The nRec Field. 0xFFFFFFFF for no-sync journals. */ - rc = write32bits(&pPager->jfd, pPager->noSync ? 0xffffffff : 0); - } - if( rc==SQLITE_OK ){ - /* The random check-hash initialiser */ - sqlite3Randomness(sizeof(pPager->cksumInit), &pPager->cksumInit); - rc = write32bits(&pPager->jfd, pPager->cksumInit); - } - if( rc==SQLITE_OK ){ - /* The initial database size */ - rc = write32bits(&pPager->jfd, pPager->dbSize); - } - if( rc==SQLITE_OK ){ - /* The assumed sector size for this process */ - rc = write32bits(&pPager->jfd, pPager->sectorSize); - } - - /* The journal header has been written successfully. Seek the journal - ** file descriptor to the end of the journal header sector. - */ - if( rc==SQLITE_OK ){ - sqlite3OsSeek(&pPager->jfd, pPager->journalOff-1); - rc = sqlite3OsWrite(&pPager->jfd, "\000", 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 */ - - rc = seekJournalHdr(pPager); - if( rc ) return rc; - - if( pPager->journalOff+JOURNAL_HDR_SZ(pPager) > journalSize ){ - return SQLITE_DONE; - } - - rc = sqlite3OsRead(&pPager->jfd, aMagic, sizeof(aMagic)); - if( rc ) return rc; - - if( memcmp(aMagic, aJournalMagic, sizeof(aMagic))!=0 ){ - return SQLITE_DONE; - } - - rc = read32bits(&pPager->jfd, pNRec); - if( rc ) return rc; - - rc = read32bits(&pPager->jfd, &pPager->cksumInit); - if( rc ) return rc; - - rc = read32bits(&pPager->jfd, 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, (u32 *)&pPager->sectorSize); - if( rc ) return rc; - - pPager->journalOff += JOURNAL_HDR_SZ(pPager); - rc = sqlite3OsSeek(&pPager->jfd, pPager->journalOff); - return rc; -} - - -/* -** 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. -*/ -static int writeMasterJournal(Pager *pPager, const char *zMaster){ - int rc; - int len; - int i; - u32 cksum = 0; - - if( !zMaster || pPager->setMaster) return SQLITE_OK; - pPager->setMaster = 1; - - len = strlen(zMaster); - for(i=0; i<len; i++){ - cksum += zMaster[i]; - } - - /* If in full-sync mode, advance to the next disk sector before writing - ** the master journal name. This is in case the previous page written to - ** the journal has already been synced. - */ - if( pPager->fullSync ){ - rc = seekJournalHdr(pPager); - if( rc!=SQLITE_OK ) return rc; - } - pPager->journalOff += (len+20); - - rc = write32bits(&pPager->jfd, PAGER_MJ_PGNO(pPager)); - if( rc!=SQLITE_OK ) return rc; - - rc = sqlite3OsWrite(&pPager->jfd, zMaster, len); - if( rc!=SQLITE_OK ) return rc; - - rc = write32bits(&pPager->jfd, len); - if( rc!=SQLITE_OK ) return rc; - - rc = write32bits(&pPager->jfd, cksum); - if( rc!=SQLITE_OK ) return rc; - - rc = sqlite3OsWrite(&pPager->jfd, aJournalMagic, sizeof(aJournalMagic)); - pPager->needSync = 1; - 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 sqlite3pager_stmt_commit() -** 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; - if( pPg->inStmt ) return; - assert( pPg->pPrevStmt==0 && pPg->pNextStmt==0 ); - pPg->pPrevStmt = 0; - if( pPager->pStmt ){ - pPager->pStmt->pPrevStmt = pPg; - } - pPg->pNextStmt = pPager->pStmt; - pPager->pStmt = pPg; - pPg->inStmt = 1; -} -static void page_remove_from_stmt_list(PgHdr *pPg){ - if( !pPg->inStmt ) return; - if( pPg->pPrevStmt ){ - assert( pPg->pPrevStmt->pNextStmt==pPg ); - pPg->pPrevStmt->pNextStmt = pPg->pNextStmt; - }else{ - assert( pPg->pPager->pStmt==pPg ); - pPg->pPager->pStmt = pPg->pNextStmt; - } - if( pPg->pNextStmt ){ - assert( pPg->pNextStmt->pPrevStmt==pPg ); - pPg->pNextStmt->pPrevStmt = pPg->pPrevStmt; - } - pPg->pNextStmt = 0; - pPg->pPrevStmt = 0; - pPg->inStmt = 0; -} - -/* -** 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 = pPager->aHash[pager_hash(pgno)]; - while( p && p->pgno!=pgno ){ - p = p->pNextHash; - } - return p; -} - -/* -** Unlock the database and 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; - for(pPg=pPager->pAll; pPg; pPg=pNext){ - pNext = pPg->pNextAll; - sqliteFree(pPg); - } - pPager->pFirst = 0; - pPager->pFirstSynced = 0; - pPager->pLast = 0; - pPager->pAll = 0; - memset(pPager->aHash, 0, sizeof(pPager->aHash)); - pPager->nPage = 0; - if( pPager->state>=PAGER_RESERVED ){ - sqlite3pager_rollback(pPager); - } - sqlite3OsUnlock(&pPager->fd, NO_LOCK); - pPager->state = PAGER_UNLOCK; - pPager->dbSize = -1; - pPager->nRef = 0; - assert( pPager->journalOpen==0 ); -} - -/* -** When this routine is called, the pager has the journal file open and -** a RESERVED or EXCLUSIVE lock on the database. This routine releases -** the database lock and acquires a SHARED lock in its place. The journal -** file is deleted and closed. -** -** 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_unwritelock(Pager *pPager){ - PgHdr *pPg; - int rc; - assert( !pPager->memDb ); - if( pPager->state<PAGER_RESERVED ){ - return SQLITE_OK; - } - sqlite3pager_stmt_commit(pPager); - if( pPager->stmtOpen ){ - sqlite3OsClose(&pPager->stfd); - pPager->stmtOpen = 0; - } - if( pPager->journalOpen ){ - sqlite3OsClose(&pPager->jfd); - pPager->journalOpen = 0; - sqlite3OsDelete(pPager->zJournal); - sqliteFree( pPager->aInJournal ); - pPager->aInJournal = 0; - for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){ - pPg->inJournal = 0; - pPg->dirty = 0; - pPg->needSync = 0; - } - pPager->dirtyCache = 0; - pPager->nRec = 0; - }else{ - assert( pPager->dirtyCache==0 || pPager->useJournal==0 ); - } - rc = sqlite3OsUnlock(&pPager->fd, SHARED_LOCK); - pPager->state = PAGER_SHARED; - pPager->origDbSize = 0; - pPager->setMaster = 0; - return 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, Pgno pgno, const char *aData){ - u32 cksum = pPager->cksumInit; - int i = pPager->pageSize-200; - while( i>0 ){ - cksum += aData[i]; - i -= 200; - } - return cksum; -} - -/* -** 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, OsFile *jfd, 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[SQLITE_MAX_PAGE_SIZE]; /* Temp storage for a page */ - - rc = read32bits(jfd, &pgno); - if( rc!=SQLITE_OK ) return rc; - rc = sqlite3OsRead(jfd, &aData, pPager->pageSize); - 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, &cksum); - if( rc ) return rc; - pPager->journalOff += 4; - if( pager_cksum(pPager, pgno, 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. - ** - ** If in EXCLUSIVE state, then we update the pager cache if it exists - ** and the main file. The page is then marked not dirty. - */ - pPg = pager_lookup(pPager, pgno); - assert( pPager->state>=PAGER_EXCLUSIVE || pPg ); - TRACE3("PLAYBACK %d page %d\n", pPager->fd.h, pgno); - if( pPager->state>=PAGER_EXCLUSIVE ){ - sqlite3OsSeek(&pPager->fd, (pgno-1)*(i64)pPager->pageSize); - rc = sqlite3OsWrite(&pPager->fd, aData, pPager->pageSize); - } - if( pPg ){ - /* No page should ever be 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. - */ - void *pData; - assert( pPg->nRef==0 || pPg->pgno==1 ); - pData = PGHDR_TO_DATA(pPg); - memcpy(pData, aData, pPager->pageSize); - if( pPager->xDestructor ){ /*** FIX ME: Should this be xReinit? ***/ - pPager->xDestructor(pData, pPager->pageSize); - } - if( pPager->state>=PAGER_EXCLUSIVE ){ - pPg->dirty = 0; - pPg->needSync = 0; - } - CODEC(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. -** -** 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(const char *zMaster){ - int rc; - int master_open = 0; - OsFile master; - 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. - */ - memset(&master, 0, sizeof(master)); - rc = sqlite3OsOpenReadOnly(zMaster, &master); - if( rc!=SQLITE_OK ) goto delmaster_out; - master_open = 1; - rc = sqlite3OsFileSize(&master, &nMasterJournal); - if( rc!=SQLITE_OK ) goto delmaster_out; - - if( nMasterJournal>0 ){ - char *zJournal; - char *zMasterPtr = 0; - - /* Load the entire master journal file into space obtained from - ** sqliteMalloc() and pointed to by zMasterJournal. - */ - zMasterJournal = (char *)sqliteMalloc(nMasterJournal); - if( !zMasterJournal ){ - rc = SQLITE_NOMEM; - goto delmaster_out; - } - rc = sqlite3OsRead(&master, zMasterJournal, nMasterJournal); - if( rc!=SQLITE_OK ) goto delmaster_out; - - zJournal = zMasterJournal; - while( (zJournal-zMasterJournal)<nMasterJournal ){ - if( sqlite3OsFileExists(zJournal) ){ - /* One of the journals pointed to by the master journal exists. - ** Open it and check if it points at the master journal. If - ** so, return without deleting the master journal file. - */ - OsFile journal; - - memset(&journal, 0, sizeof(journal)); - rc = sqlite3OsOpenReadOnly(zJournal, &journal); - if( rc!=SQLITE_OK ){ - goto delmaster_out; - } - - rc = readMasterJournal(&journal, &zMasterPtr); - sqlite3OsClose(&journal); - if( rc!=SQLITE_OK ){ - goto delmaster_out; - } - - if( zMasterPtr && !strcmp(zMasterPtr, zMaster) ){ - /* We have a match. Do not delete the master journal file. */ - goto delmaster_out; - } - } - zJournal += (strlen(zJournal)+1); - } - } - - sqlite3OsDelete(zMaster); - -delmaster_out: - if( zMasterJournal ){ - sqliteFree(zMasterJournal); - } - if( master_open ){ - sqlite3OsClose(&master); - } - return rc; -} - -/* -** Make every page in the cache agree with what is on disk. In other words, -** reread the disk to reset the state of the cache. -** -** This routine is called after a rollback in which some of the dirty cache -** pages had never been written out to disk. We need to roll back the -** cache content and the easiest way to do that is to reread the old content -** back from the disk. -*/ -static int pager_reload_cache(Pager *pPager){ - PgHdr *pPg; - int rc = SQLITE_OK; - for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){ - char zBuf[SQLITE_MAX_PAGE_SIZE]; - if( !pPg->dirty ) continue; - if( (int)pPg->pgno <= pPager->origDbSize ){ - sqlite3OsSeek(&pPager->fd, pPager->pageSize*(i64)(pPg->pgno-1)); - rc = sqlite3OsRead(&pPager->fd, zBuf, pPager->pageSize); - TRACE3("REFETCH %d page %d\n", pPager->fd.h, pPg->pgno); - if( rc ) break; - CODEC(pPager, zBuf, pPg->pgno, 2); - }else{ - memset(zBuf, 0, pPager->pageSize); - } - if( pPg->nRef==0 || memcmp(zBuf, PGHDR_TO_DATA(pPg), pPager->pageSize) ){ - memcpy(PGHDR_TO_DATA(pPg), zBuf, pPager->pageSize); - if( pPager->xReiniter ){ - pPager->xReiniter(PGHDR_TO_DATA(pPg), pPager->pageSize); - }else{ - memset(PGHDR_TO_EXTRA(pPg, pPager), 0, pPager->nExtra); - } - } - pPg->needSync = 0; - pPg->dirty = 0; - } - return rc; -} - -/* -** Truncate the main file of the given pager to the number of pages -** indicated. -*/ -static int pager_truncate(Pager *pPager, int nPage){ - return sqlite3OsTruncate(&pPager->fd, pPager->pageSize*(i64)nPage); -} - -/* -** 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){ - 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 ){ - 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. - */ - rc = readMasterJournal(&pPager->jfd, &zMaster); - assert( rc!=SQLITE_DONE ); - if( rc!=SQLITE_OK || (zMaster && !sqlite3OsFileExists(zMaster)) ){ - sqliteFree(zMaster); - zMaster = 0; - if( rc==SQLITE_DONE ) rc = SQLITE_OK; - goto end_playback; - } - sqlite3OsSeek(&pPager->jfd, 0); - pPager->journalOff = 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 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) ){ - assert( pPager->origDbSize==0 || pPager->origDbSize==mxPg ); - rc = pager_truncate(pPager, mxPg); - if( rc!=SQLITE_OK ){ - goto end_playback; - } - pPager->dbSize = mxPg; - } - - /* rc = sqlite3OsSeek(&pPager->jfd, JOURNAL_HDR_SZ(pPager)); */ - if( rc!=SQLITE_OK ) goto end_playback; - - /* Copy original pages out of the journal and back into the database file. - */ - for(i=0; i<nRec; i++){ - rc = pager_playback_one_page(pPager, &pPager->jfd, 1); - if( rc!=SQLITE_OK ){ - if( rc==SQLITE_DONE ){ - rc = SQLITE_OK; - pPager->journalOff = szJ; - break; - }else{ - goto end_playback; - } - } - } - } - - /* Pages that have been written to the journal but never synced - ** where not restored by the loop above. We have to restore those - ** pages by reading them back from the original database. - */ - assert( rc==SQLITE_OK ); - pager_reload_cache(pPager); - -end_playback: - if( rc==SQLITE_OK ){ - rc = pager_unwritelock(pPager); - } - if( zMaster ){ - /* If there was a master journal and this routine will return true, - ** see if it is possible to delete the master journal. If errors - ** occur during this process, ignore them. - */ - if( rc==SQLITE_OK ){ - pager_delmaster(zMaster); - } - sqliteFree(zMaster); - } - - /* The Pager.sectorSize variable may have been updated while rolling - ** back a journal created by a process with a different PAGER_SECTOR_SIZE - ** value. Reset it to the correct value for this process. - */ - pPager->sectorSize = PAGER_SECTOR_SIZE; - 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 to the first journal header written - ** this statement transaction, 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); - pPager->dbSize = pPager->stmtSize; - - /* Figure out how many records are in the statement journal. - */ - assert( pPager->stmtInUse && pPager->journalOpen ); - sqlite3OsSeek(&pPager->stfd, 0); - 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=nRec-1; i>=0; i--){ - rc = pager_playback_one_page(pPager, &pPager->stfd, 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. - */ - rc = sqlite3OsSeek(&pPager->jfd, pPager->stmtJSize); - if( rc!=SQLITE_OK ){ - goto end_stmt_playback; - } - pPager->journalOff = pPager->stmtJSize; - pPager->cksumInit = pPager->stmtCksum; - assert( JOURNAL_HDR_SZ(pPager)<(pPager->pageSize+8) ); - while( pPager->journalOff <= (hdrOff-(pPager->pageSize+8)) ){ - rc = pager_playback_one_page(pPager, &pPager->jfd, 1); - assert( rc!=SQLITE_DONE ); - if( rc!=SQLITE_OK ) goto end_stmt_playback; - } - - while( pPager->journalOff < szJ ){ - u32 nRec; - u32 dummy; - rc = readJournalHdr(pPager, szJ, &nRec, &dummy); - if( rc!=SQLITE_OK ){ - assert( rc!=SQLITE_DONE ); - goto end_stmt_playback; - } - if( nRec==0 ){ - nRec = (szJ - pPager->journalOff) / (pPager->pageSize+8); - } - for(i=nRec-1; i>=0 && pPager->journalOff < szJ; i--){ - rc = pager_playback_one_page(pPager, &pPager->jfd, 1); - assert( rc!=SQLITE_DONE ); - if( rc!=SQLITE_OK ) goto end_stmt_playback; - } - } - - pPager->journalOff = szJ; - -end_stmt_playback: - if( rc!=SQLITE_OK ){ - pPager->errMask |= PAGER_ERR_CORRUPT; - rc = SQLITE_CORRUPT; /* bkpt-CORRUPT */ - }else{ - pPager->journalOff = szJ; - /* pager_reload_cache(pPager); */ - } - return rc; -} - -/* -** Change the maximum number of in-memory pages that are allowed. -** -** The maximum number is the absolute value of the mxPage parameter. -** If mxPage is negative, the noSync flag is also set. noSync bypasses -** calls to sqlite3OsSync(). The pager runs much faster with noSync on, -** but if the operating system crashes or there is an abrupt power -** failure, the database file might be left in an inconsistent and -** unrepairable state. -*/ -void sqlite3pager_set_cachesize(Pager *pPager, int mxPage){ - if( mxPage>=0 ){ - pPager->noSync = pPager->tempFile; - if( pPager->noSync ) pPager->needSync = 0; - }else{ - pPager->noSync = 1; - mxPage = -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. -*/ -void sqlite3pager_set_safety_level(Pager *pPager, int level){ - pPager->noSync = level==1 || pPager->tempFile; - pPager->fullSync = level==3 && !pPager->tempFile; - if( pPager->noSync ) pPager->needSync = 0; -} - -/* -** Open a temporary file. Write the name of the file into zName -** (zName must be at least SQLITE_TEMPNAME_SIZE bytes long.) 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 sqlite3pager_opentemp(char *zFile, OsFile *fd){ - int cnt = 8; - int rc; - do{ - cnt--; - sqlite3OsTempFileName(zFile); - rc = sqlite3OsOpenExclusive(zFile, fd, 1); - }while( cnt>0 && rc!=SQLITE_OK && rc!=SQLITE_NOMEM ); - 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 sqlite3pager_get() and is only held open until the -** last page is released using sqlite3pager_unref(). -** -** 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 sqlite3pager_open( - 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 useJournal /* TRUE to use a rollback journal on this file */ -){ - Pager *pPager; - char *zFullPathname = 0; - int nameLen; - OsFile fd; - int rc = SQLITE_OK; - int i; - int tempFile = 0; - int memDb = 0; - int readOnly = 0; - char zTemp[SQLITE_TEMPNAME_SIZE]; - - *ppPager = 0; - memset(&fd, 0, sizeof(fd)); - if( sqlite3_malloc_failed ){ - return SQLITE_NOMEM; - } - if( zFilename && zFilename[0] ){ - if( strcmp(zFilename,":memory:")==0 ){ - memDb = 1; - zFullPathname = sqliteStrDup(""); - rc = SQLITE_OK; - }else{ - zFullPathname = sqlite3OsFullPathname(zFilename); - if( zFullPathname ){ - rc = sqlite3OsOpenReadWrite(zFullPathname, &fd, &readOnly); - } - } - }else{ - rc = sqlite3pager_opentemp(zTemp, &fd); - zFilename = zTemp; - zFullPathname = sqlite3OsFullPathname(zFilename); - if( rc==SQLITE_OK ){ - tempFile = 1; - } - } - if( !zFullPathname ){ - sqlite3OsClose(&fd); - return SQLITE_NOMEM; - } - if( rc!=SQLITE_OK ){ - sqlite3OsClose(&fd); - sqliteFree(zFullPathname); - return rc; - } - nameLen = strlen(zFullPathname); - pPager = sqliteMalloc( sizeof(*pPager) + nameLen*3 + 30 ); - if( pPager==0 ){ - sqlite3OsClose(&fd); - sqliteFree(zFullPathname); - return SQLITE_NOMEM; - } - TRACE3("OPEN %d %s\n", fd.h, zFullPathname); - pPager->zFilename = (char*)&pPager[1]; - pPager->zDirectory = &pPager->zFilename[nameLen+1]; - pPager->zJournal = &pPager->zDirectory[nameLen+1]; - strcpy(pPager->zFilename, zFullPathname); - strcpy(pPager->zDirectory, zFullPathname); - for(i=nameLen; i>0 && pPager->zDirectory[i-1]!='/'; i--){} - if( i>0 ) pPager->zDirectory[i-1] = 0; - strcpy(pPager->zJournal, zFullPathname); - sqliteFree(zFullPathname); - strcpy(&pPager->zJournal[nameLen], "-journal"); - pPager->fd = fd; -#if OS_UNIX - pPager->fd.pPager = pPager; -#endif - pPager->journalOpen = 0; - pPager->useJournal = useJournal && !memDb; - pPager->stmtOpen = 0; - pPager->stmtInUse = 0; - pPager->nRef = 0; - pPager->dbSize = memDb-1; - pPager->pageSize = SQLITE_DEFAULT_PAGE_SIZE; - pPager->stmtSize = 0; - pPager->stmtJSize = 0; - pPager->nPage = 0; - pPager->mxPage = 100; - pPager->state = PAGER_UNLOCK; - pPager->errMask = 0; - pPager->tempFile = tempFile; - pPager->memDb = memDb; - pPager->readOnly = readOnly; - pPager->needSync = 0; - pPager->noSync = pPager->tempFile || !useJournal; - pPager->fullSync = (pPager->noSync?0:1); - pPager->pFirst = 0; - pPager->pFirstSynced = 0; - pPager->pLast = 0; - pPager->nExtra = nExtra; - pPager->sectorSize = PAGER_SECTOR_SIZE; - pPager->pBusyHandler = 0; - memset(pPager->aHash, 0, sizeof(pPager->aHash)); - *ppPager = pPager; - return SQLITE_OK; -} - -/* -** Set the busy handler function. -*/ -void sqlite3pager_set_busyhandler(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 sqlite3pager_close(). -** Destructors are only called by sqlite3pager_unref(). -*/ -void sqlite3pager_set_destructor(Pager *pPager, void (*xDesc)(void*,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 sqlite3pager_set_reiniter(Pager *pPager, void (*xReinit)(void*,int)){ - pPager->xReiniter = xReinit; -} - -/* -** Set the page size. -** -** The page size must only be changed when the cache is empty. -*/ -void sqlite3pager_set_pagesize(Pager *pPager, int pageSize){ - assert( pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE ); - pPager->pageSize = pageSize; -} - -/* -** Read the first N bytes from the beginning of the file into memory -** that pDest points to. No error checking is done. -*/ -void sqlite3pager_read_fileheader(Pager *pPager, int N, unsigned char *pDest){ - memset(pDest, 0, N); - if( pPager->memDb==0 ){ - sqlite3OsSeek(&pPager->fd, 0); - sqlite3OsRead(&pPager->fd, pDest, N); - } -} - -/* -** Return the total number of pages in the disk file associated with -** pPager. -*/ -int sqlite3pager_pagecount(Pager *pPager){ - i64 n; - assert( pPager!=0 ); - if( pPager->dbSize>=0 ){ - return pPager->dbSize; - } - if( sqlite3OsFileSize(&pPager->fd, &n)!=SQLITE_OK ){ - pPager->errMask |= PAGER_ERR_DISK; - return 0; - } - n /= pPager->pageSize; - if( !pPager->memDb && n==PENDING_BYTE/pPager->pageSize ){ - n++; - } - if( pPager->state!=PAGER_UNLOCK ){ - pPager->dbSize = n; - } - return n; -} - -/* -** Forward declaration -*/ -static int syncJournal(Pager*); - - -/* -** 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; - - /* Keep the pFirstSynced pointer pointing at the first synchronized page */ - if( pPg==pPager->pFirstSynced ){ - PgHdr *p = pPg->pNextFree; - while( p && p->needSync ){ p = p->pNextFree; } - pPager->pFirstSynced = p; - } - - /* Unlink from the freelist */ - if( pPg->pPrevFree ){ - pPg->pPrevFree->pNextFree = pPg->pNextFree; - }else{ - assert( pPager->pFirst==pPg ); - pPager->pFirst = pPg->pNextFree; - } - if( pPg->pNextFree ){ - pPg->pNextFree->pPrevFree = pPg->pPrevFree; - }else{ - assert( pPager->pLast==pPg ); - pPager->pLast = pPg->pPrevFree; - } - pPg->pNextFree = pPg->pPrevFree = 0; - - /* Unlink from the pgno hash table */ - if( pPg->pNextHash ){ - pPg->pNextHash->pPrevHash = pPg->pPrevHash; - } - if( pPg->pPrevHash ){ - pPg->pPrevHash->pNextHash = pPg->pNextHash; - }else{ - int h = pager_hash(pPg->pgno); - assert( pPager->aHash[h]==pPg ); - pPager->aHash[h] = pPg->pNextHash; - } - pPg->pNextHash = pPg->pPrevHash = 0; -} - -/* -** This routine is used to truncate an in-memory database. Delete -** all pages whose pgno is larger than pPager->dbSize and is unreferenced. -** Referenced pages larger than pPager->dbSize are zeroed. -*/ -static void memoryTruncate(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; - unlinkPage(pPg); - sqliteFree(pPg); - pPager->nPage--; - } - } -} - -/* -** Truncate the file to the number of pages specified. -*/ -int sqlite3pager_truncate(Pager *pPager, Pgno nPage){ - int rc; - sqlite3pager_pagecount(pPager); - if( pPager->errMask!=0 ){ - rc = pager_errcode(pPager); - return rc; - } - if( nPage>=(unsigned)pPager->dbSize ){ - return SQLITE_OK; - } - if( pPager->memDb ){ - pPager->dbSize = nPage; - memoryTruncate(pPager); - return SQLITE_OK; - } - rc = syncJournal(pPager); - if( rc!=SQLITE_OK ){ - return rc; - } - rc = pager_truncate(pPager, nPage); - if( rc==SQLITE_OK ){ - pPager->dbSize = 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. -*/ -int sqlite3pager_close(Pager *pPager){ - PgHdr *pPg, *pNext; - switch( pPager->state ){ - case PAGER_RESERVED: - case PAGER_SYNCED: - case PAGER_EXCLUSIVE: { - sqlite3pager_rollback(pPager); - if( !pPager->memDb ){ - sqlite3OsUnlock(&pPager->fd, NO_LOCK); - } - assert( pPager->journalOpen==0 ); - break; - } - case PAGER_SHARED: { - if( !pPager->memDb ){ - sqlite3OsUnlock(&pPager->fd, NO_LOCK); - } - break; - } - default: { - /* Do nothing */ - break; - } - } - for(pPg=pPager->pAll; pPg; pPg=pNext){ -#ifndef NDEBUG - if( pPager->memDb ){ - PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager); - assert( !pPg->alwaysRollback ); - assert( !pHist->pOrig ); - assert( !pHist->pStmt ); - } -#endif - pNext = pPg->pNextAll; - sqliteFree(pPg); - } - TRACE2("CLOSE %d\n", pPager->fd.h); - sqlite3OsClose(&pPager->fd); - assert( pPager->journalOpen==0 ); - /* Temp files are automatically deleted by the OS - ** if( pPager->tempFile ){ - ** sqlite3OsDelete(pPager->zFilename); - ** } - */ - if( pPager->zFilename!=(char*)&pPager[1] ){ - assert( 0 ); /* Cannot happen */ - sqliteFree(pPager->zFilename); - sqliteFree(pPager->zJournal); - sqliteFree(pPager->zDirectory); - } - sqliteFree(pPager); - return SQLITE_OK; -} - -/* -** Return the page number for the given page data. -*/ -Pgno sqlite3pager_pagenumber(void *pData){ - PgHdr *p = DATA_TO_PGHDR(pData); - return p->pgno; -} - -/* -** 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. */ - if( pPg==pPg->pPager->pFirstSynced ){ - PgHdr *p = pPg->pNextFree; - while( p && p->needSync ){ p = p->pNextFree; } - pPg->pPager->pFirstSynced = p; - } - if( pPg->pPrevFree ){ - pPg->pPrevFree->pNextFree = pPg->pNextFree; - }else{ - pPg->pPager->pFirst = pPg->pNextFree; - } - if( pPg->pNextFree ){ - pPg->pNextFree->pPrevFree = pPg->pPrevFree; - }else{ - pPg->pPager->pLast = pPg->pPrevFree; - } - pPg->pPager->nRef++; - } - pPg->nRef++; - REFINFO(pPg); -} -#ifdef SQLITE_TEST - 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 sqlite3pager_ref(void *pData){ - PgHdr *pPg = DATA_TO_PGHDR(pData); - page_ref(pPg); - 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 sync occurs. -** -** 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 ){ - 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 - { - /* 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. - */ - if( pPager->fullSync ){ - TRACE2("SYNC journal of %d\n", pPager->fd.h); - rc = sqlite3OsSync(&pPager->jfd); - if( rc!=0 ) return rc; - } - sqlite3OsSeek(&pPager->jfd, pPager->journalHdr + sizeof(aJournalMagic)); - rc = write32bits(&pPager->jfd, pPager->nRec); - if( rc ) return rc; - - sqlite3OsSeek(&pPager->jfd, pPager->journalOff); - } - TRACE2("SYNC journal of %d\n", pPager->fd.h); - rc = sqlite3OsSync(&pPager->jfd); - 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; - } - pPager->pFirstSynced = pPager->pFirst; - } - -#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->pFirstSynced==pPager->pFirst ); - } -#endif - - return rc; -} - -/* -** Try to obtain a lock on a file. Invoke the busy callback if the lock -** is currently not available. Repeate 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; - assert( PAGER_SHARED==SHARED_LOCK ); - assert( PAGER_RESERVED==RESERVED_LOCK ); - assert( PAGER_EXCLUSIVE==EXCLUSIVE_LOCK ); - if( pPager->state>=locktype ){ - rc = SQLITE_OK; - }else{ - int busy = 1; - do { - rc = sqlite3OsLock(&pPager->fd, locktype); - }while( rc==SQLITE_BUSY && - pPager->pBusyHandler && - pPager->pBusyHandler->xFunc && - pPager->pBusyHandler->xFunc(pPager->pBusyHandler->pArg, busy++) - ); - if( rc==SQLITE_OK ){ - pPager->state = locktype; - } - } - return rc; -} - -/* -** Given a list of pages (connected by the PgHdr.pDirty pointer) write -** every one of those pages out to the database file and mark them all -** as clean. -*/ -static int pager_write_pagelist(PgHdr *pList){ - Pager *pPager; - int rc; - - if( pList==0 ) return SQLITE_OK; - pPager = pList->pPager; - - /* At this point there may be either a RESERVED or EXCLUSIVE lock on the - ** database file. If there is already an EXCLUSIVE lock, the following - ** calls to sqlite3OsLock() are no-ops. - ** - ** Moving the lock from RESERVED to EXCLUSIVE actually involves going - ** through an intermediate state PENDING. A PENDING lock prevents new - ** readers from attaching to the database but is unsufficient for us to - ** write. The idea of a PENDING lock is to prevent new readers from - ** coming in while we wait for existing readers to clear. - ** - ** While the pager is in the RESERVED state, the original database file - ** is unchanged and we can rollback without having to playback the - ** journal into the original database file. Once we transition to - ** EXCLUSIVE, it means the database file has been changed and any rollback - ** will require a journal playback. - */ - rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK); - if( rc!=SQLITE_OK ){ - return rc; - } - - while( pList ){ - assert( pList->dirty ); - sqlite3OsSeek(&pPager->fd, (pList->pgno-1)*(i64)pPager->pageSize); - CODEC(pPager, PGHDR_TO_DATA(pList), pList->pgno, 6); - TRACE3("STORE %d page %d\n", pPager->fd.h, pList->pgno); - rc = sqlite3OsWrite(&pPager->fd, PGHDR_TO_DATA(pList), pPager->pageSize); - CODEC(pPager, PGHDR_TO_DATA(pList), pList->pgno, 0); - if( rc ) return rc; - pList->dirty = 0; - 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){ - PgHdr *p, *pList; - pList = 0; - for(p=pPager->pAll; p; p=p->pNextAll){ - if( p->dirty ){ - p->pDirty = pList; - pList = p; - } - } - return pList; -} - -/* -** 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. -** -** A _get 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 sqlite3pager_lookup(). 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. -*/ -int sqlite3pager_get(Pager *pPager, Pgno pgno, void **ppPage){ - PgHdr *pPg; - int rc; - - /* Make sure we have not hit any critical errors. - */ - assert( pPager!=0 ); - assert( pgno!=0 ); - *ppPage = 0; - if( pPager->errMask & ~(PAGER_ERR_FULL) ){ - return pager_errcode(pPager); - } - - /* If this is the first page accessed, then get a SHARED lock - ** on the database file. - */ - if( pPager->nRef==0 && !pPager->memDb ){ - rc = pager_wait_on_lock(pPager, SHARED_LOCK); - if( rc!=SQLITE_OK ){ - return rc; - } - - /* 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( pPager->useJournal && - sqlite3OsFileExists(pPager->zJournal) && - !sqlite3OsCheckReservedLock(&pPager->fd) - ){ - int rc; - - /* 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. - */ - rc = sqlite3OsLock(&pPager->fd, EXCLUSIVE_LOCK); - if( rc!=SQLITE_OK ){ - sqlite3OsUnlock(&pPager->fd, NO_LOCK); - pPager->state = PAGER_UNLOCK; - return 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. - */ - rc = sqlite3OsOpenReadOnly(pPager->zJournal, &pPager->jfd); - if( rc!=SQLITE_OK ){ - sqlite3OsUnlock(&pPager->fd, NO_LOCK); - pPager->state = PAGER_UNLOCK; - return 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); - if( rc!=SQLITE_OK ){ - return rc; - } - } - pPg = 0; - }else{ - /* Search for page in cache */ - pPg = pager_lookup(pPager, pgno); - if( pPager->memDb && pPager->state==PAGER_UNLOCK ){ - pPager->state = PAGER_SHARED; - } - } - if( pPg==0 ){ - /* The requested page is not in the page cache. */ - int h; - pPager->nMiss++; - if( pPager->nPage<pPager->mxPage || pPager->pFirst==0 || pPager->memDb ){ - /* Create a new page */ - pPg = sqliteMallocRaw( sizeof(*pPg) + pPager->pageSize - + sizeof(u32) + pPager->nExtra - + pPager->memDb*sizeof(PgHistory) ); - if( pPg==0 ){ - if( !pPager->memDb ){ - pager_unwritelock(pPager); - } - pPager->errMask |= PAGER_ERR_MEM; - return SQLITE_NOMEM; - } - memset(pPg, 0, sizeof(*pPg)); - if( pPager->memDb ){ - memset(PGHDR_TO_HIST(pPg, pPager), 0, sizeof(PgHistory)); - } - pPg->pPager = pPager; - pPg->pNextAll = pPager->pAll; - pPager->pAll = pPg; - pPager->nPage++; - }else{ - /* Find a page to recycle. Try to locate a page that does not - ** require us to do an fsync() on the journal. - */ - pPg = pPager->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 ){ - int rc = syncJournal(pPager); - if( rc!=0 ){ - sqlite3pager_rollback(pPager); - return SQLITE_IOERR; - } - if( pPager->fullSync ){ - /* 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 ); - rc = writeJournalHdr(pPager); - if( rc!=0 ){ - sqlite3pager_rollback(pPager); - return SQLITE_IOERR; - } - } - pPg = pPager->pFirst; - } - assert( pPg->nRef==0 ); - - /* Write the page to the database file if it is dirty. - */ - if( pPg->dirty ){ - assert( pPg->needSync==0 ); - pPg->pDirty = 0; - rc = pager_write_pagelist( pPg ); - if( rc!=SQLITE_OK ){ - sqlite3pager_rollback(pPager); - return SQLITE_IOERR; - } - } - assert( pPg->dirty==0 ); - - /* If the page we are recycling is marked as alwaysRollback, then - ** set the global alwaysRollback flag, thus disabling the - ** sqlite_dont_rollback() 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 ){ - pPager->alwaysRollback = 1; - } - - /* Unlink the old page from the free list and the hash table - */ - unlinkPage(pPg); - pPager->nOvfl++; - } - pPg->pgno = pgno; - if( pPager->aInJournal && (int)pgno<=pPager->origDbSize ){ - sqlite3CheckMemory(pPager->aInJournal, pgno/8); - assert( pPager->journalOpen ); - pPg->inJournal = (pPager->aInJournal[pgno/8] & (1<<(pgno&7)))!=0; - pPg->needSync = 0; - }else{ - pPg->inJournal = 0; - pPg->needSync = 0; - } - if( pPager->aInStmt && (int)pgno<=pPager->stmtSize - && (pPager->aInStmt[pgno/8] & (1<<(pgno&7)))!=0 ){ - page_add_to_stmt_list(pPg); - }else{ - page_remove_from_stmt_list(pPg); - } - pPg->dirty = 0; - pPg->nRef = 1; - REFINFO(pPg); - pPager->nRef++; - h = pager_hash(pgno); - pPg->pNextHash = pPager->aHash[h]; - pPager->aHash[h] = pPg; - if( pPg->pNextHash ){ - assert( pPg->pNextHash->pPrevHash==0 ); - pPg->pNextHash->pPrevHash = pPg; - } - if( pPager->nExtra>0 ){ - memset(PGHDR_TO_EXTRA(pPg, pPager), 0, pPager->nExtra); - } - sqlite3pager_pagecount(pPager); - if( pPager->errMask!=0 ){ - sqlite3pager_unref(PGHDR_TO_DATA(pPg)); - rc = pager_errcode(pPager); - return rc; - } - if( pPager->dbSize<(int)pgno ){ - memset(PGHDR_TO_DATA(pPg), 0, pPager->pageSize); - }else{ - int rc; - assert( pPager->memDb==0 ); - sqlite3OsSeek(&pPager->fd, (pgno-1)*(i64)pPager->pageSize); - rc = sqlite3OsRead(&pPager->fd, PGHDR_TO_DATA(pPg), pPager->pageSize); - TRACE3("FETCH %d page %d\n", pPager->fd.h, pPg->pgno); - CODEC(pPager, PGHDR_TO_DATA(pPg), pPg->pgno, 3); - if( rc!=SQLITE_OK ){ - i64 fileSize; - if( sqlite3OsFileSize(&pPager->fd,&fileSize)!=SQLITE_OK - || fileSize>=pgno*pPager->pageSize ){ - sqlite3pager_unref(PGHDR_TO_DATA(pPg)); - return rc; - }else{ - memset(PGHDR_TO_DATA(pPg), 0, pPager->pageSize); - } - } - } - }else{ - /* The requested page is in the page cache. */ - pPager->nHit++; - page_ref(pPg); - } - *ppPage = PGHDR_TO_DATA(pPg); - return SQLITE_OK; -} - -/* -** 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 sqlite3pager_get(). The difference between this routine -** and sqlite3pager_get() 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. -*/ -void *sqlite3pager_lookup(Pager *pPager, Pgno pgno){ - PgHdr *pPg; - - assert( pPager!=0 ); - assert( pgno!=0 ); - if( pPager->errMask & ~(PAGER_ERR_FULL) ){ - return 0; - } - pPg = pager_lookup(pPager, pgno); - if( pPg==0 ) return 0; - page_ref(pPg); - return PGHDR_TO_DATA(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 sqlite3pager_unref(void *pData){ - PgHdr *pPg; - - /* Decrement the reference count for this page - */ - pPg = DATA_TO_PGHDR(pData); - assert( pPg->nRef>0 ); - pPg->nRef--; - REFINFO(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 ){ - Pager *pPager; - pPager = pPg->pPager; - pPg->pNextFree = 0; - pPg->pPrevFree = pPager->pLast; - pPager->pLast = pPg; - if( pPg->pPrevFree ){ - pPg->pPrevFree->pNextFree = pPg; - }else{ - pPager->pFirst = pPg; - } - if( pPg->needSync==0 && pPager->pFirstSynced==0 ){ - pPager->pFirstSynced = pPg; - } - if( pPager->xDestructor ){ - pPager->xDestructor(pData, 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->memDb ){ - pager_reset(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){ - int rc; - assert( !pPager->memDb ); - assert( pPager->state>=PAGER_RESERVED ); - assert( pPager->journalOpen==0 ); - assert( pPager->useJournal ); - sqlite3pager_pagecount(pPager); - pPager->aInJournal = sqliteMalloc( pPager->dbSize/8 + 1 ); - if( pPager->aInJournal==0 ){ - rc = SQLITE_NOMEM; - goto failed_to_open_journal; - } - rc = sqlite3OsOpenExclusive(pPager->zJournal, &pPager->jfd,pPager->tempFile); - pPager->journalOff = 0; - pPager->setMaster = 0; - pPager->journalHdr = 0; - if( rc!=SQLITE_OK ){ - goto failed_to_open_journal; - } - sqlite3OsOpenDirectory(pPager->zDirectory, &pPager->jfd); - pPager->journalOpen = 1; - pPager->journalStarted = 0; - pPager->needSync = 0; - pPager->alwaysRollback = 0; - pPager->nRec = 0; - if( pPager->errMask!=0 ){ - rc = pager_errcode(pPager); - return rc; - } - pPager->origDbSize = pPager->dbSize; - - rc = writeJournalHdr(pPager); - - if( pPager->stmtAutoopen && rc==SQLITE_OK ){ - rc = sqlite3pager_stmt_begin(pPager); - } - if( rc!=SQLITE_OK ){ - rc = pager_unwritelock(pPager); - if( rc==SQLITE_OK ){ - rc = SQLITE_FULL; - } - } - return rc; - -failed_to_open_journal: - sqliteFree(pPager->aInJournal); - pPager->aInJournal = 0; - sqlite3OsUnlock(&pPager->fd, NO_LOCK); - pPager->state = PAGER_UNLOCK; - return rc; -} - -/* -** Acquire a write-lock on the database. The lock is removed when -** the any of the following happen: -** -** * sqlite3pager_commit() is called. -** * sqlite3pager_rollback() is called. -** * sqlite3pager_close() is called. -** * sqlite3pager_unref() 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 sqlite3pager_begin(void *pData, int exFlag){ - PgHdr *pPg = DATA_TO_PGHDR(pData); - Pager *pPager = pPg->pPager; - int rc = SQLITE_OK; - assert( pPg->nRef>0 ); - assert( pPager->state!=PAGER_UNLOCK ); - if( pPager->state==PAGER_SHARED ){ - assert( pPager->aInJournal==0 ); - if( pPager->memDb ){ - pPager->state = PAGER_EXCLUSIVE; - pPager->origDbSize = pPager->dbSize; - }else{ - if( SQLITE_BUSY_RESERVED_LOCK || exFlag ){ - rc = pager_wait_on_lock(pPager, RESERVED_LOCK); - }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 ){ - return rc; - } - pPager->dirtyCache = 0; - TRACE2("TRANSACTION %d\n", pPager->fd.h); - if( pPager->useJournal && !pPager->tempFile ){ - rc = pager_open_journal(pPager); - } - } - } - return rc; -} - -/* -** 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 sqlite3pager_commit() or sqlite3pager_rollback() to -** reset. -*/ -int sqlite3pager_write(void *pData){ - PgHdr *pPg = DATA_TO_PGHDR(pData); - Pager *pPager = pPg->pPager; - int rc = SQLITE_OK; - - /* Check for errors - */ - if( pPager->errMask ){ - return pager_errcode(pPager); - } - if( pPager->readOnly ){ - return SQLITE_PERM; - } - - assert( !pPager->setMaster ); - - /* Mark the page as dirty. If the page has already been written - ** to the journal then we can return right away. - */ - pPg->dirty = 1; - if( pPg->inJournal && (pPg->inStmt || pPager->stmtInUse==0) ){ - pPager->dirtyCache = 1; - return SQLITE_OK; - } - - /* 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 = sqlite3pager_begin(pData, 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 || pPager->memDb) ){ - if( (int)pPg->pgno <= pPager->origDbSize ){ - int szPg; - u32 saved; - if( pPager->memDb ){ - PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager); - TRACE3("JOURNAL %d page %d\n", pPager->fd.h, pPg->pgno); - assert( pHist->pOrig==0 ); - pHist->pOrig = sqliteMallocRaw( pPager->pageSize ); - if( pHist->pOrig ){ - memcpy(pHist->pOrig, PGHDR_TO_DATA(pPg), pPager->pageSize); - } - }else{ - u32 cksum; - CODEC(pPager, pData, pPg->pgno, 7); - cksum = pager_cksum(pPager, pPg->pgno, pData); - saved = *(u32*)PGHDR_TO_EXTRA(pPg, pPager); - store32bits(cksum, pPg, pPager->pageSize); - szPg = pPager->pageSize+8; - store32bits(pPg->pgno, pPg, -4); - rc = sqlite3OsWrite(&pPager->jfd, &((char*)pData)[-4], szPg); - pPager->journalOff += szPg; - TRACE4("JOURNAL %d page %d needSync=%d\n", - pPager->fd.h, pPg->pgno, pPg->needSync); - CODEC(pPager, pData, pPg->pgno, 0); - *(u32*)PGHDR_TO_EXTRA(pPg, pPager) = saved; - if( rc!=SQLITE_OK ){ - sqlite3pager_rollback(pPager); - pPager->errMask |= PAGER_ERR_FULL; - 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); - page_add_to_stmt_list(pPg); - } - } - }else{ - pPg->needSync = !pPager->journalStarted && !pPager->noSync; - TRACE4("APPEND %d page %d needSync=%d\n", - pPager->fd.h, 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 && !pPg->inStmt && (int)pPg->pgno<=pPager->stmtSize ){ - assert( pPg->inJournal || (int)pPg->pgno>pPager->origDbSize ); - if( pPager->memDb ){ - PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager); - assert( pHist->pStmt==0 ); - pHist->pStmt = sqliteMallocRaw( pPager->pageSize ); - if( pHist->pStmt ){ - memcpy(pHist->pStmt, PGHDR_TO_DATA(pPg), pPager->pageSize); - } - TRACE3("STMT-JOURNAL %d page %d\n", pPager->fd.h, pPg->pgno); - }else{ - store32bits(pPg->pgno, pPg, -4); - CODEC(pPager, pData, pPg->pgno, 7); - rc = sqlite3OsWrite(&pPager->stfd, ((char*)pData)-4, pPager->pageSize+4); - TRACE3("STMT-JOURNAL %d page %d\n", pPager->fd.h, pPg->pgno); - CODEC(pPager, pData, pPg->pgno, 0); - if( rc!=SQLITE_OK ){ - sqlite3pager_rollback(pPager); - pPager->errMask |= PAGER_ERR_FULL; - return rc; - } - pPager->stmtNRec++; - assert( pPager->aInStmt!=0 ); - pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7); - } - page_add_to_stmt_list(pPg); - } - - /* Update the database size and return. - */ - if( pPager->dbSize<(int)pPg->pgno ){ - pPager->dbSize = pPg->pgno; - if( !pPager->memDb && pPager->dbSize==PENDING_BYTE/pPager->pageSize ){ - pPager->dbSize++; - } - } - return rc; -} - -/* -** Return TRUE if the page given in the argument was previously passed -** to sqlite3pager_write(). In other words, return TRUE if it is ok -** to change the content of the page. -*/ -int sqlite3pager_iswriteable(void *pData){ - PgHdr *pPg = DATA_TO_PGHDR(pData); - return pPg->dirty; -} - -/* -** Replace the content of a single page with the information in the third -** argument. -*/ -int sqlite3pager_overwrite(Pager *pPager, Pgno pgno, void *pData){ - void *pPage; - int rc; - - rc = sqlite3pager_get(pPager, pgno, &pPage); - if( rc==SQLITE_OK ){ - rc = sqlite3pager_write(pPage); - if( rc==SQLITE_OK ){ - memcpy(pPage, pData, pPager->pageSize); - } - sqlite3pager_unref(pPage); - } - return rc; -} - -/* -** A call to this routine tells the pager that it is not necessary to -** write the information on page "pgno" 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 -** sqlite3pager_dont_rollback() 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 sqlite3pager_dont_rollback() 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 dont_rollback() routine is called. But because the page contains -** critical data, we still need to be sure it gets rolled back in spite -** of the dont_rollback() call. -*/ -void sqlite3pager_dont_write(Pager *pPager, Pgno pgno){ - PgHdr *pPg; - - if( pPager->memDb ) return; - - pPg = pager_lookup(pPager, pgno); - pPg->alwaysRollback = 1; - if( pPg && pPg->dirty ){ - if( pPager->dbSize==(int)pPg->pgno && pPager->origDbSize<pPager->dbSize ){ - /* If this pages is the last page in the file and the file has grown - ** during the current transaction, then do NOT mark the page as clean. - ** When the database file grows, we must make sure that the last page - ** gets written at least once so that the disk file will be the correct - ** size. If you do not write this page and the size of the file - ** on the disk ends up being too small, that can lead to database - ** corruption during the next transaction. - */ - }else{ - TRACE3("DONT_WRITE page %d of %d\n", pgno, pPager->fd.h); - pPg->dirty = 0; - } - } -} - -/* -** 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. -*/ -void sqlite3pager_dont_rollback(void *pData){ - PgHdr *pPg = DATA_TO_PGHDR(pData); - Pager *pPager = pPg->pPager; - - if( pPager->state!=PAGER_EXCLUSIVE || pPager->journalOpen==0 ) return; - if( pPg->alwaysRollback || pPager->alwaysRollback || pPager->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; - if( pPager->stmtInUse ){ - pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7); - page_add_to_stmt_list(pPg); - } - TRACE3("DONT_ROLLBACK page %d of %d\n", pPg->pgno, pPager->fd.h); - } - if( pPager->stmtInUse && !pPg->inStmt && (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); - page_add_to_stmt_list(pPg); - } -} - - -/* -** Clear a PgHistory block -*/ -static void clearHistory(PgHistory *pHist){ - sqliteFree(pHist->pOrig); - sqliteFree(pHist->pStmt); - pHist->pOrig = 0; - pHist->pStmt = 0; -} - -/* -** 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 sqlite3pager_commit(Pager *pPager){ - int rc; - PgHdr *pPg; - - if( pPager->errMask==PAGER_ERR_FULL ){ - rc = sqlite3pager_rollback(pPager); - if( rc==SQLITE_OK ){ - rc = SQLITE_FULL; - } - return rc; - } - if( pPager->errMask!=0 ){ - rc = pager_errcode(pPager); - return rc; - } - if( pPager->state<PAGER_RESERVED ){ - return SQLITE_ERROR; - } - TRACE2("COMMIT %d\n", pPager->fd.h); - if( pPager->memDb ){ - pPg = pager_get_all_dirty_pages(pPager); - while( pPg ){ - clearHistory(PGHDR_TO_HIST(pPg, pPager)); - pPg->dirty = 0; - pPg->inJournal = 0; - pPg->inStmt = 0; - pPg->pPrevStmt = pPg->pNextStmt = 0; - pPg = pPg->pDirty; - } -#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; - } - if( pPager->dirtyCache==0 ){ - /* Exit early (without doing the time-consuming sqlite3OsSync() calls) - ** if there have been no changes to the database file. */ - assert( pPager->needSync==0 ); - rc = pager_unwritelock(pPager); - pPager->dbSize = -1; - return rc; - } - assert( pPager->journalOpen ); - rc = sqlite3pager_sync(pPager, 0); - if( rc!=SQLITE_OK ){ - goto commit_abort; - } - rc = pager_unwritelock(pPager); - pPager->dbSize = -1; - return rc; - - /* Jump here if anything goes wrong during the commit process. - */ -commit_abort: - sqlite3pager_rollback(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 (SQLITE_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 sqlite3pager_rollback(Pager *pPager){ - int rc; - TRACE2("ROLLBACK %d\n", pPager->fd.h); - if( pPager->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); - TRACE3("ROLLBACK-PAGE %d of %d\n", p->pgno, pPager->fd.h); - }else{ - TRACE3("PAGE %d is clean on %d\n", p->pgno, pPager->fd.h); - } - clearHistory(pHist); - p->dirty = 0; - p->inJournal = 0; - p->inStmt = 0; - p->pPrevStmt = p->pNextStmt = 0; - - if( pPager->xReiniter ){ - pPager->xReiniter(PGHDR_TO_DATA(p), pPager->pageSize); - } - - } - pPager->pStmt = 0; - pPager->dbSize = pPager->origDbSize; - memoryTruncate(pPager); - pPager->stmtInUse = 0; - pPager->state = PAGER_SHARED; - return SQLITE_OK; - } - - if( !pPager->dirtyCache || !pPager->journalOpen ){ - rc = pager_unwritelock(pPager); - pPager->dbSize = -1; - return rc; - } - - if( pPager->errMask!=0 && pPager->errMask!=PAGER_ERR_FULL ){ - if( pPager->state>=PAGER_EXCLUSIVE ){ - pager_playback(pPager); - } - return pager_errcode(pPager); - } - if( pPager->state==PAGER_RESERVED ){ - int rc2, rc3; - rc = pager_reload_cache(pPager); - rc2 = pager_truncate(pPager, pPager->origDbSize); - rc3 = pager_unwritelock(pPager); - if( rc==SQLITE_OK ){ - rc = rc2; - if( rc3 ) rc = rc3; - } - }else{ - rc = pager_playback(pPager); - } - if( rc!=SQLITE_OK ){ - rc = SQLITE_CORRUPT; /* bkpt-CORRUPT */ - pPager->errMask |= PAGER_ERR_CORRUPT; - } - pPager->dbSize = -1; - return rc; -} - -/* -** Return TRUE if the database file is opened read-only. Return FALSE -** if the database is (in theory) writable. -*/ -int sqlite3pager_isreadonly(Pager *pPager){ - return pPager->readOnly; -} - -/* -** This routine is used for testing and analysis only. -*/ -int *sqlite3pager_stats(Pager *pPager){ - static int a[9]; - a[0] = pPager->nRef; - a[1] = pPager->nPage; - a[2] = pPager->mxPage; - a[3] = pPager->dbSize; - a[4] = pPager->state; - a[5] = pPager->errMask; - a[6] = pPager->nHit; - a[7] = pPager->nMiss; - a[8] = pPager->nOvfl; - return a; -} - -/* -** 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. -*/ -int sqlite3pager_stmt_begin(Pager *pPager){ - int rc; - char zTemp[SQLITE_TEMPNAME_SIZE]; - assert( !pPager->stmtInUse ); - assert( pPager->dbSize>=0 ); - TRACE2("STMT-BEGIN %d\n", pPager->fd.h); - if( pPager->memDb ){ - pPager->stmtInUse = 1; - pPager->stmtSize = pPager->dbSize; - return SQLITE_OK; - } - if( !pPager->journalOpen ){ - pPager->stmtAutoopen = 1; - return SQLITE_OK; - } - assert( pPager->journalOpen ); - pPager->aInStmt = sqliteMalloc( pPager->dbSize/8 + 1 ); - 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 = sqlite3pager_opentemp(zTemp, &pPager->stfd); - if( rc ) goto stmt_begin_failed; - pPager->stmtOpen = 1; - pPager->stmtNRec = 0; - } - pPager->stmtInUse = 1; - return SQLITE_OK; - -stmt_begin_failed: - if( pPager->aInStmt ){ - sqliteFree(pPager->aInStmt); - pPager->aInStmt = 0; - } - return rc; -} - -/* -** Commit a statement. -*/ -int sqlite3pager_stmt_commit(Pager *pPager){ - if( pPager->stmtInUse ){ - PgHdr *pPg, *pNext; - TRACE2("STMT-COMMIT %d\n", pPager->fd.h); - if( !pPager->memDb ){ - sqlite3OsSeek(&pPager->stfd, 0); - /* sqlite3OsTruncate(&pPager->stfd, 0); */ - sqliteFree( pPager->aInStmt ); - pPager->aInStmt = 0; - } - for(pPg=pPager->pStmt; pPg; pPg=pNext){ - pNext = pPg->pNextStmt; - assert( pPg->inStmt ); - pPg->inStmt = 0; - pPg->pPrevStmt = pPg->pNextStmt = 0; - if( pPager->memDb ){ - PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager); - sqliteFree(pHist->pStmt); - pHist->pStmt = 0; - } - } - pPager->stmtNRec = 0; - pPager->stmtInUse = 0; - pPager->pStmt = 0; - } - pPager->stmtAutoopen = 0; - return SQLITE_OK; -} - -/* -** Rollback a statement. -*/ -int sqlite3pager_stmt_rollback(Pager *pPager){ - int rc; - if( pPager->stmtInUse ){ - TRACE2("STMT-ROLLBACK %d\n", pPager->fd.h); - if( pPager->memDb ){ - PgHdr *pPg; - for(pPg=pPager->pStmt; pPg; pPg=pPg->pNextStmt){ - PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager); - if( pHist->pStmt ){ - memcpy(PGHDR_TO_DATA(pPg), pHist->pStmt, pPager->pageSize); - sqliteFree(pHist->pStmt); - pHist->pStmt = 0; - } - } - pPager->dbSize = pPager->stmtSize; - memoryTruncate(pPager); - rc = SQLITE_OK; - }else{ - rc = pager_stmt_playback(pPager); - } - sqlite3pager_stmt_commit(pPager); - }else{ - rc = SQLITE_OK; - } - pPager->stmtAutoopen = 0; - return rc; -} - -/* -** Return the full pathname of the database file. -*/ -const char *sqlite3pager_filename(Pager *pPager){ - return pPager->zFilename; -} - -/* -** Return the directory of the database file. -*/ -const char *sqlite3pager_dirname(Pager *pPager){ - return pPager->zDirectory; -} - -/* -** Return the full pathname of the journal file. -*/ -const char *sqlite3pager_journalname(Pager *pPager){ - return pPager->zJournal; -} - -/* -** Set the codec for this pager -*/ -void sqlite3pager_set_codec( - Pager *pPager, - void (*xCodec)(void*,void*,Pgno,int), - void *pCodecArg -){ - pPager->xCodec = xCodec; - pPager->pCodecArg = pCodecArg; -} - -/* -** 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){ - void *pPage; - PgHdr *pPgHdr; - u32 change_counter; - int rc; - - /* Open page 1 of the file for writing. */ - rc = sqlite3pager_get(pPager, 1, &pPage); - if( rc!=SQLITE_OK ) return rc; - rc = sqlite3pager_write(pPage); - if( rc!=SQLITE_OK ) return rc; - - /* Read the current value at byte 24. */ - pPgHdr = DATA_TO_PGHDR(pPage); - change_counter = retrieve32bits(pPgHdr, 24); - - /* Increment the value just read and write it back to byte 24. */ - change_counter++; - store32bits(change_counter, pPgHdr, 24); - - /* Release the page reference. */ - sqlite3pager_unref(pPage); - return SQLITE_OK; -} - -/* -** 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 sqlite3pager_sync() call. -*/ -int sqlite3pager_sync(Pager *pPager, const char *zMaster){ - int rc = SQLITE_OK; - - /* 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 && !pPager->memDb && pPager->dirtyCache ){ - PgHdr *pPg; - assert( pPager->journalOpen ); - - /* 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 ){ - rc = pager_incr_changecounter(pPager); - if( rc!=SQLITE_OK ) goto sync_exit; - rc = writeMasterJournal(pPager, zMaster); - if( rc!=SQLITE_OK ) goto sync_exit; - rc = syncJournal(pPager); - if( rc!=SQLITE_OK ) goto sync_exit; - } - - /* Write all dirty pages to the database file */ - pPg = pager_get_all_dirty_pages(pPager); - rc = pager_write_pagelist(pPg); - if( rc!=SQLITE_OK ) goto sync_exit; - - /* Sync the database file. */ - if( !pPager->noSync ){ - rc = sqlite3OsSync(&pPager->fd); - } - - pPager->state = PAGER_SYNCED; - } - -sync_exit: - return rc; -} - -#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST) -/* -** Return the current state of the file lock for the given pager. -** The return value is one of NO_LOCK, SHARED_LOCK, RESERVED_LOCK, -** PENDING_LOCK, or EXCLUSIVE_LOCK. -*/ -int sqlite3pager_lockstate(Pager *pPager){ -#ifdef OS_TEST - return pPager->fd->fd.locktype; -#else - return pPager->fd.locktype; -#endif -} -#endif - -#ifdef SQLITE_TEST -/* -** Print a listing of all referenced pages and their ref count. -*/ -void sqlite3pager_refdump(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 |