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diff --git a/kopete/plugins/statistics/sqlite/pager.c b/kopete/plugins/statistics/sqlite/pager.c
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-/*
-** 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