SQLite

/*
** 2004 April 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.549 2008/12/17 17:30:26 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
** Including a description of file format and an overview of operation.
*/
#include "btreeInt.h"

      pBt->pExclusive = p;
    }
#endif
  }


trans_begun:
  if( rc==SQLITE_OK && wrflag ){
    rc = sqlite3PagerOpenSavepoint(pBt->pPager, p->db->nSavepoint);
  }
  btreeIntegrity(p);
  sqlite3BtreeLeave(p);
  return rc;
}

#ifndef SQLITE_OMIT_AUTOVACUUM

  BtShared *pBt = p->pBt;
  sqlite3BtreeEnter(p);
  pBt->db = p->db;
  if( (p->inTrans!=TRANS_WRITE) || pBt->inStmt ){
    rc = pBt->readOnly ? SQLITE_READONLY : SQLITE_ERROR;
  }else{
    assert( pBt->inTransaction==TRANS_WRITE );
    if( pBt->readOnly ){
      rc = SQLITE_OK;
    }else{
      /* At the pager level, a statement transaction is a savepoint with
      ** an index greater than all savepoints created explicitly using
      ** SQL statements. It is illegal to open, release or rollback any
      ** such savepoints while the statement transaction savepoint is active.
      */
      int iStmtpoint = p->db->nSavepoint + 1;
      rc = sqlite3PagerOpenSavepoint(pBt->pPager, iStmtpoint);
    }
    pBt->inStmt = 1;
  }
  sqlite3BtreeLeave(p);
  return rc;
}


/*
** Commit the statment subtransaction currently in progress.  If no
** subtransaction is active, this is a no-op.
*/
int sqlite3BtreeCommitStmt(Btree *p){
  int rc;
  BtShared *pBt = p->pBt;
  sqlite3BtreeEnter(p);
  pBt->db = p->db;
  if( pBt->inStmt && !pBt->readOnly ){
    int iStmtpoint = p->db->nSavepoint;
    rc = sqlite3PagerSavepoint(pBt->pPager, SAVEPOINT_RELEASE, iStmtpoint);
  }else{
    rc = SQLITE_OK;
  }
  pBt->inStmt = 0;
  sqlite3BtreeLeave(p);
  return rc;
}

*/
int sqlite3BtreeRollbackStmt(Btree *p){
  int rc = SQLITE_OK;
  BtShared *pBt = p->pBt;
  sqlite3BtreeEnter(p);
  pBt->db = p->db;
  if( pBt->inStmt && !pBt->readOnly ){
    int iStmtpoint = p->db->nSavepoint;
    rc = sqlite3PagerSavepoint(pBt->pPager, SAVEPOINT_ROLLBACK, iStmtpoint);
    if( rc==SQLITE_OK ){
      rc = sqlite3PagerSavepoint(pBt->pPager, SAVEPOINT_RELEASE, iStmtpoint);
    }
    pBt->inStmt = 0;
  }
  sqlite3BtreeLeave(p);
  return rc;
}

/*
** The second argument to this function, op, is always SAVEPOINT_ROLLBACK
** or SAVEPOINT_RELEASE. This function either releases or rolls back the
** savepoint identified by parameter iSavepoint, depending on the value of
** op.
*/
int sqlite3BtreeSavepoint(Btree *p, int op, int iSavepoint){
  int rc = SQLITE_OK;
  if( p && p->inTrans==TRANS_WRITE ){
    BtShared *pBt = p->pBt;
    assert( pBt->inStmt==0 );
    assert( op==SAVEPOINT_RELEASE || op==SAVEPOINT_ROLLBACK );
    assert( iSavepoint>=0 || (iSavepoint==-1 && op==SAVEPOINT_ROLLBACK) );
    sqlite3BtreeEnter(p);
    pBt->db = p->db;
    rc = sqlite3PagerSavepoint(pBt->pPager, op, iSavepoint);
    sqlite3BtreeLeave(p);
  }
  return rc;
}

/*
** Create a new cursor for the BTree whose root is on the page
** iTable.  The act of acquiring a cursor gets a read lock on 
** the database file.
**
** If wrFlag==0, then the cursor can only be used for reading.

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface that the sqlite B-Tree file
** subsystem.  See comments in the source code for a detailed description
** of what each interface routine does.
**
** @(#) $Id: btree.h,v 1.106 2008/12/17 17:30:26 danielk1977 Exp $
*/
#ifndef _BTREE_H_
#define _BTREE_H_

/* TODO: This definition is just included so other modules compile. It
** needs to be revisited.
*/

int sqlite3BtreeCreateTable(Btree*, int*, int flags);
int sqlite3BtreeIsInTrans(Btree*);
int sqlite3BtreeIsInStmt(Btree*);
int sqlite3BtreeIsInReadTrans(Btree*);
void *sqlite3BtreeSchema(Btree *, int, void(*)(void *));
int sqlite3BtreeSchemaLocked(Btree *);
int sqlite3BtreeLockTable(Btree *, int, u8);
int sqlite3BtreeSavepoint(Btree *, int, int);

const char *sqlite3BtreeGetFilename(Btree *);
const char *sqlite3BtreeGetDirname(Btree *);
const char *sqlite3BtreeGetJournalname(Btree *);
int sqlite3BtreeCopyFile(Btree *, Btree *);

int sqlite3BtreeIncrVacuum(Btree *);

**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.509 2008/12/17 17:30:26 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Initialize the pParse structure as needed.

  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION, "ROLLBACK", 0, 0) ) return;

  v = sqlite3GetVdbe(pParse);
  if( v ){
    sqlite3VdbeAddOp2(v, OP_AutoCommit, 1, 1);
  }
}

/*
** This function is called by the parser when it parses a command to create,
** release or rollback an SQL savepoint. 
*/
void sqlite3Savepoint(Parse *pParse, int op, Token *pName){
  Vdbe *v;
  if( pParse->nErr || pParse->db->mallocFailed ) return;

  /* TODO: Invoke the authorization callback */

  v = sqlite3GetVdbe(pParse);
  if( v ){
    const char *zName = (const char *)pName->z;
    sqlite3VdbeAddOp4(v, OP_Savepoint, op, 0, 0, zName, pName->n);
  }
}

/*
** Make sure the TEMP database is open and available for use.  Return
** the number of errors.  Leave any error messages in the pParse structure.
*/
int sqlite3OpenTempDatabase(Parse *pParse){
  sqlite3 *db = pParse->db;

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.520 2008/12/17 17:30:26 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

#ifdef SQLITE_ENABLE_FTS3
# include "fts3.h"
#endif

/*
** Return the number of changes since the database handle was opened.
*/
int sqlite3_total_changes(sqlite3 *db){
  return db->nTotalChange;
}

/*
** Close all open savepoints. This function only manipulates fields of the
** database handle object, it does not close any savepoints that may be open
** at the b-tree/pager level.
*/
void sqlite3CloseSavepoints(sqlite3 *db){
  while( db->pSavepoint ){
    Savepoint *pTmp = db->pSavepoint;
    db->pSavepoint = pTmp->pNext;
    sqlite3DbFree(db, pTmp);
  }
  db->nSavepoint = 0;
  db->isTransactionSavepoint = 0;
}

/*
** Close an existing SQLite database
*/
int sqlite3_close(sqlite3 *db){
  HashElem *i;
  int j;

  if( db->pVdbe ){
    sqlite3Error(db, SQLITE_BUSY, 
        "Unable to close due to unfinalised statements");
    sqlite3_mutex_leave(db->mutex);
    return SQLITE_BUSY;
  }
  assert( sqlite3SafetyCheckSickOrOk(db) );

  /* Free any outstanding Savepoint structures. */
  sqlite3CloseSavepoints(db);

  for(j=0; j<db->nDb; j++){
    struct Db *pDb = &db->aDb[j];
    if( pDb->pBt ){
      sqlite3BtreeClose(pDb->pBt);
      pDb->pBt = 0;
      if( j!=1 ){

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.515 2008/12/17 17:30:26 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"

/*
** Macros for troubleshooting.  Normally turned off
*/

# define CODEC1(P,D,N,X) if( P->xCodec!=0 ){ P->xCodec(P->pCodecArg,D,N,X); }
# define CODEC2(P,D,N,X) ((char*)(P->xCodec!=0?P->xCodec(P->pCodecArg,D,N,X):D))
#else
# define CODEC1(P,D,N,X) /* NO-OP */
# define CODEC2(P,D,N,X) ((char*)D)
#endif

/*
** An instance of the following structure is allocated for each active
** savepoint and statement transaction in the system. All such structures
** are stored in the Pager.aSavepoint[] array, which is allocated and
** resized using sqlite3Realloc().
**
** When a savepoint is created, the PagerSavepoint.iHdrOffset field is
** set to 0. If a journal-header is written into the main journal while
** the savepoint is active, then iHdrOffset is set to the byte offset 
** immediately following the last journal record written into the main
** journal before the journal-header. This is required during savepoint
** rollback (see pagerPlaybackSavepoint()).
*/
typedef struct PagerSavepoint PagerSavepoint;
struct PagerSavepoint {
  i64 iOffset;                 /* Starting offset in main journal */
  i64 iHdrOffset;              /* See above */
  Bitvec *pInSavepoint;        /* Set of pages in this savepoint */
  Pgno nOrig;                  /* Original number of pages in file */
  Pgno iSubRec;                /* Index of first record in sub-journal */
};

/*
** A open page cache is an instance of the following structure.
**
** Pager.errCode may be set to SQLITE_IOERR, SQLITE_CORRUPT, or
** or SQLITE_FULL. Once one of the first three errors occurs, it persists
** and is returned as the result of every major pager API call.  The
** SQLITE_FULL return code is slightly different. It persists only until the
** next successful rollback is performed on the pager cache. Also,
** SQLITE_FULL does not affect the sqlite3PagerGet() and sqlite3PagerLookup()
** APIs, they may still be used successfully.
*/
struct Pager {
  sqlite3_vfs *pVfs;          /* OS functions to use for IO */
  u8 journalOpen;             /* True if journal file descriptors is valid */
  u8 journalStarted;          /* True if header of journal is synced */
  u8 useJournal;              /* Use a rollback journal on this file */
  u8 noReadlock;              /* Do not bother to obtain readlocks */



  u8 noSync;                  /* Do not sync the journal if true */
  u8 fullSync;                /* Do extra syncs of the journal for robustness */
  u8 sync_flags;              /* One of SYNC_NORMAL or SYNC_FULL */
  u8 state;                   /* PAGER_UNLOCK, _SHARED, _RESERVED, etc. */
  u8 tempFile;                /* zFilename is a temporary file */
  u8 readOnly;                /* True for a read-only database */
  u8 needSync;                /* True if an fsync() is needed on the journal */

  u8 dbModified;              /* True if there are any changes to the Db */
  u8 changeCountDone;         /* Set after incrementing the change-counter */
  u8 dbSizeValid;             /* Set when dbSize is correct */
  u32 vfsFlags;               /* Flags for sqlite3_vfs.xOpen() */
  int errCode;                /* One of several kinds of errors */
  Pgno dbSize;                /* Number of pages in the file */
  Pgno origDbSize;            /* dbSize before the current change */

  int nRec;                   /* Number of pages written to the journal */
  u32 cksumInit;              /* Quasi-random value added to every checksum */
  int stmtNRec;               /* Number of records in stmt subjournal */
  int nExtra;                 /* Add this many bytes to each in-memory page */
  int pageSize;               /* Number of bytes in a page */
  int nPage;                  /* Total number of in-memory pages */
  int mxPage;                 /* Maximum number of pages to hold in cache */
  Pgno mxPgno;                /* Maximum allowed size of the database */
  Bitvec *pInJournal;         /* One bit for each page in the database file */

  Bitvec *pAlwaysRollback;    /* One bit for each page marked always-rollback */
  char *zFilename;            /* Name of the database file */
  char *zJournal;             /* Name of the journal file */
  char *zDirectory;           /* Directory hold database and journal files */
  sqlite3_file *fd, *jfd;     /* File descriptors for database and journal */
  sqlite3_file *sjfd;         /* File descriptor for the sub-journal*/
  int (*xBusyHandler)(void*); /* Function to call when busy */
  void *pBusyHandlerArg;      /* Context argument for xBusyHandler */
  i64 journalOff;             /* Current byte offset in the journal file */
  i64 journalHdr;             /* Byte offset to previous journal header */



  u32 sectorSize;             /* Assumed sector size during rollback */
#ifdef SQLITE_TEST
  int nHit, nMiss;            /* Cache hits and missing */
  int nRead, nWrite;          /* Database pages read/written */
#endif
  void (*xReiniter)(DbPage*); /* Call this routine when reloading pages */
#ifdef SQLITE_HAS_CODEC
  void *(*xCodec)(void*,void*,Pgno,int); /* Routine for en/decoding data */
  void *pCodecArg;            /* First argument to xCodec() */
#endif
  char *pTmpSpace;            /* Pager.pageSize bytes of space for tmp use */
  char dbFileVers[16];        /* Changes whenever database file changes */
  i64 journalSizeLimit;       /* Size limit for persistent journal files */
  PCache *pPCache;            /* Pointer to page cache object */

  PagerSavepoint *aSavepoint;
  int nSavepoint;
};

/*
** The following global variables hold counters used for
** testing purposes only.  These variables do not exist in
** a non-testing build.  These variables are not thread-safe.
*/

/*
** The maximum legal page number is (2^31 - 1).
*/
#define PAGER_MAX_PGNO 2147483647

/*
** Return false if it is necessary to write page *pPg into the sub-journal.
** More accurately, true is returned if either:
**
**   * No savepoints are open, or
**   * The page has been saved to the sub-journal since the most recent
**     savepoint was opened.
**
** TODO: There's a bug here. To do with PagerSavepoint.nOrig. Also consider
**       the idea that the page may not be required by the outermost savepoint
**       but may be required by some earlier savepoint, due to an incremental
**       vacuum operation.
*/
static int pageInSavepoint(PgHdr *pPg){
  Pager *pPager = pPg->pPager;
  if( pPager->nSavepoint==0 ){
    return 1;
  }
  return sqlite3BitvecTest(
      pPager->aSavepoint[pPager->nSavepoint-1].pInSavepoint, pPg->pgno
  );
}

static int pageInJournal(PgHdr *pPg){
  return sqlite3BitvecTest(pPg->pPager->pInJournal, pPg->pgno);
}

/*

** Followed by (JOURNAL_HDR_SZ - 28) bytes of unused space.
*/
static int writeJournalHdr(Pager *pPager){
  int rc = SQLITE_OK;
  char *zHeader = pPager->pTmpSpace;
  u32 nHeader = pPager->pageSize;
  u32 nWrite;
  int ii;

  if( nHeader>JOURNAL_HDR_SZ(pPager) ){
    nHeader = JOURNAL_HDR_SZ(pPager);
  }

  /* If there are active savepoints and any of them were created since the
  ** most recent journal header was written, update the PagerSavepoint.iHdrOff
  ** fields now.
  */
  for(ii=0; ii<pPager->nSavepoint; ii++){
    if( pPager->aSavepoint[ii].iHdrOffset==0 ){
      pPager->aSavepoint[ii].iHdrOffset = pPager->journalOff;
    }
  }

  seekJournalHdr(pPager);
  pPager->journalHdr = pPager->journalOff;

  memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));

** 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){
  if( pPager->errCode ) return;
  sqlite3PcacheClear(pPager->pPCache);
}

static void releaseAllSavepoint(Pager *pPager){
  int ii;
  for(ii=0; ii<pPager->nSavepoint; ii++){
    sqlite3BitvecDestroy(pPager->aSavepoint[ii].pInSavepoint);
  }
  if( !pPager->exclusiveMode ){
    sqlite3OsClose(pPager->sjfd);
  }
  sqlite3_free(pPager->aSavepoint);
  pPager->aSavepoint = 0;
  pPager->nSavepoint = 0;
}

static int addToSavepointBitvecs(Pager *pPager, Pgno pgno){
  int ii;
  for(ii=0; ii<pPager->nSavepoint; ii++){
    PagerSavepoint *p = &pPager->aSavepoint[ii];
    if( pgno<=p->nOrig ){
      /* TODO: malloc() failure handling */
      sqlite3BitvecSet(p->pInSavepoint, pgno);
    }
  }
  return SQLITE_OK;
}

/*
** Unlock the database file. 
**
** If the pager is currently in error state, discard the contents of 
** the cache and reset the Pager structure internal state. If there is
** an open journal-file, then the next time a shared-lock is obtained

    /* If Pager.errCode is set, the contents of the pager cache cannot be
    ** trusted. Now that the pager file is unlocked, the contents of the
    ** cache can be discarded and the error code safely cleared.
    */
    if( pPager->errCode ){
      if( rc==SQLITE_OK ) pPager->errCode = SQLITE_OK;
      pager_reset(pPager);

      releaseAllSavepoint(pPager);





      pPager->journalOff = 0;
      pPager->journalStarted = 0;

      pPager->origDbSize = 0;
    }

    pPager->state = PAGER_UNLOCK;
    pPager->changeCountDone = 0;
  }
}

*/
static int pager_end_transaction(Pager *pPager, int hasMaster){
  int rc = SQLITE_OK;
  int rc2 = SQLITE_OK;
  if( pPager->state<PAGER_RESERVED ){
    return SQLITE_OK;
  }
  releaseAllSavepoint(pPager);




  if( pPager->journalOpen ){
    if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY ){
      int isMemoryJournal = sqlite3IsMemJournal(pPager->jfd);
      sqlite3OsClose(pPager->jfd);
      pPager->journalOpen = 0;
      if( !isMemoryJournal ){
        rc = sqlite3OsDelete(pPager->pVfs, pPager->zJournal, 0);

** jfd.  Playback this one page.
**
** The isMainJrnl flag is true if this is the main rollback journal and
** false for the statement journal.  The main rollback journal uses
** checksums - the statement journal does not.
*/
static int pager_playback_one_page(
  Pager *pPager,                /* The pager being played back */
  int isMainJrnl,               /* 1 -> main journal. 0 -> sub-journal. */
  i64 offset,                   /* Offset of record to playback */
  Bitvec *pDone                 /* Bitvec of pages already played back */
){
  int rc;
  PgHdr *pPg;                   /* An existing page in the cache */
  Pgno pgno;                    /* The page number of a page in journal */
  u32 cksum;                    /* Checksum used for sanity checking */
  u8 *aData = (u8 *)pPager->pTmpSpace;   /* Temp storage for a page */
  sqlite3_file *jfd = (isMainJrnl ? pPager->jfd : pPager->sjfd);


  /* The temp storage must be allocated at this point */


  assert( aData );

  rc = read32bits(jfd, offset, &pgno);
  if( rc!=SQLITE_OK ) return rc;
  rc = sqlite3OsRead(jfd, aData, pPager->pageSize, offset+4);
  if( rc!=SQLITE_OK ) return rc;
  pPager->journalOff += pPager->pageSize + 4;

  /* Sanity checking on the page.  This is more important that I originally
  ** thought.  If a power failure occurs while the journal is being written,
  ** it could cause invalid data to be written into the journal.  We need to
  ** detect this invalid data (with high probability) and ignore it.
  */
  if( pgno==0 || pgno==PAGER_MJ_PGNO(pPager) ){
    return SQLITE_DONE;
  }
  if( pgno>(Pgno)pPager->dbSize || sqlite3BitvecTest(pDone, pgno) ){
    return SQLITE_OK;
  }
  if( isMainJrnl ){
    rc = read32bits(jfd, offset+pPager->pageSize+4, &cksum);
    if( rc ) return rc;
    pPager->journalOff += 4;
    if( !pDone && pager_cksum(pPager, aData)!=cksum ){
      return SQLITE_DONE;
    }
  }
  if( pDone && (rc = sqlite3BitvecSet(pDone, pgno)) ){
    return rc;
  }

  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.

        goto end_playback;
      }
    }

    /* Copy original pages out of the journal and back into the database file.
    */
    for(u=0; u<nRec; u++){
      rc = pager_playback_one_page(pPager, 1, pPager->journalOff, 0);
      if( rc!=SQLITE_OK ){
        if( rc==SQLITE_DONE ){
          rc = SQLITE_OK;
          pPager->journalOff = szJ;
          break;
        }else{
          /* If we are unable to rollback, then the database is probably

  ** value. Reset it to the correct value for this process.
  */
  setSectorSize(pPager);
  return rc;
}

/*
** Playback a savepoint.











*/
static int pagerPlaybackSavepoint(Pager *pPager, PagerSavepoint *pSavepoint){
  i64 szJ;                 /* Size of the full journal */

  i64 iHdrOff;             /* End of first segment of main-journal records */
  Pgno ii;                 /* Loop counter */
  int rc;                  /* Return code */
  Bitvec *pDone = 0;       /* Bitvec to ensure pages played back only once */

  /* Allocate a bitvec to use to store the set of pages rolled back */
  if( pSavepoint ){
    pDone = sqlite3BitvecCreate(pSavepoint->nOrig);
    if( !pDone ){
      return SQLITE_NOMEM;
    }









  }

  /* Truncate the database back to the size it was before the 
  ** savepoint being reverted was opened.
  */
  rc = pager_truncate(pPager, pSavepoint?pSavepoint->nOrig:pPager->origDbSize);
  assert( pPager->state>=PAGER_SHARED );



  /* Now roll back all main journal file records that occur after byte

  ** byte offset PagerSavepoint.iOffset that have a page number less than


  ** or equal to PagerSavepoint.nOrig. As each record is played back,
  ** the corresponding bit in bitvec PagerSavepoint.pInSavepoint is 
  ** cleared.
  */

  szJ = pPager->journalOff;


  if( pSavepoint ){

    iHdrOff = pSavepoint->iHdrOffset ? pSavepoint->iHdrOffset : szJ;








    pPager->journalOff = pSavepoint->iOffset;

    while( rc==SQLITE_OK && pPager->journalOff<iHdrOff ){
      rc = pager_playback_one_page(pPager, 1, pPager->journalOff, pDone);
      assert( rc!=SQLITE_DONE );

    }
  }else{
    pPager->journalOff = 0;
  }
  while( rc==SQLITE_OK && pPager->journalOff<szJ ){
    u32 nJRec;         /* Number of Journal Records */
    u32 dummy;
    rc = readJournalHdr(pPager, szJ, &nJRec, &dummy);

    assert( rc!=SQLITE_DONE );


    if( nJRec==0 ){
      nJRec = (szJ - pPager->journalOff) / (pPager->pageSize+8);
    }
    for(ii=0; rc==SQLITE_OK && ii<nJRec; ii++){
      rc = pager_playback_one_page(pPager, 1, pPager->journalOff, pDone);
      assert( rc!=SQLITE_DONE );

    }
  }
  assert( rc!=SQLITE_OK || pPager->journalOff==szJ );

  /* Now roll back pages from the sub-journal. */
  if( pSavepoint ){
    for(ii=pSavepoint->iSubRec; rc==SQLITE_OK && ii<pPager->stmtNRec; ii++){
      i64 offset = ii*(4+pPager->pageSize);
      rc = pager_playback_one_page(pPager, 0, offset, pDone);
      assert( rc!=SQLITE_DONE );
    }
  }

  sqlite3BitvecDestroy(pDone);
  if( rc==SQLITE_OK ){
    pPager->journalOff = szJ;

  }
  return rc;
}

/*
** Change the maximum number of in-memory pages that are allowed.
*/

    sqlite3_free(zPathname);
    return SQLITE_NOMEM;
  }
  pPager->pPCache = (PCache *)&pPager[1];
  pPtr = ((u8 *)&pPager[1]) + pcacheSize;
  pPager->vfsFlags = vfsFlags;
  pPager->fd = (sqlite3_file*)&pPtr[pVfs->szOsFile*0];
  pPager->sjfd = (sqlite3_file*)&pPtr[pVfs->szOsFile];
  pPager->jfd = (sqlite3_file*)&pPtr[pVfs->szOsFile+journalFileSize];
  pPager->zFilename = (char*)&pPtr[pVfs->szOsFile+2*journalFileSize];
  pPager->zDirectory = &pPager->zFilename[nPathname+1];
  pPager->zJournal = &pPager->zDirectory[nPathname+1];
  pPager->pVfs = pVfs;
  if( zPathname ){
    memcpy(pPager->zFilename, zPathname, nPathname+1);

  PAGERTRACE2("CLOSE %d\n", PAGERID(pPager));
  IOTRACE(("CLOSE %p\n", pPager))
  if( pPager->journalOpen ){
    sqlite3OsClose(pPager->jfd);
  }
  sqlite3BitvecDestroy(pPager->pInJournal);
  sqlite3BitvecDestroy(pPager->pAlwaysRollback);

  releaseAllSavepoint(pPager);

  sqlite3OsClose(pPager->fd);
  /* Temp files are automatically deleted by the OS
  ** if( pPager->tempFile ){
  **   sqlite3OsDelete(pPager->zFilename);
  ** }
  */

  if( pPg ){
    Pager *pPager = pPg->pPager;
    sqlite3PcacheRelease(pPg);
    pagerUnlockIfUnused(pPager);
  }
  return SQLITE_OK;
}

static int openSubJournal(Pager *pPager){
  int rc = SQLITE_OK;
  if( pPager->journalOpen && !pPager->sjfd->pMethods ){
    if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY ){
      sqlite3MemJournalOpen(pPager->sjfd);
    }else{
      rc = sqlite3PagerOpentemp(pPager, pPager->sjfd, SQLITE_OPEN_SUBJOURNAL);
    }
  }
  return rc;
}

/*
** 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.

    rc = pPager->errCode;
    goto failed_to_open_journal;
  }
  pPager->origDbSize = pPager->dbSize;

  rc = writeJournalHdr(pPager);

  if( pPager->nSavepoint && rc==SQLITE_OK ){
    rc = openSubJournal(pPager);
  }
  if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM && rc!=SQLITE_IOERR_NOMEM ){
    rc = pager_end_transaction(pPager, 0);
    if( rc==SQLITE_OK ){
      rc = SQLITE_FULL;
    }
  }

    return rc;
  }

  /* Mark the page as dirty.  If the page has already been written
  ** to the journal then we can return right away.
  */
  sqlite3PcacheMakeDirty(pPg);
  if( pageInJournal(pPg) && pageInSavepoint(pPg) ){
    pPager->dirtyCache = 1;
    pPager->dbModified = 1;
  }else{

    /* If we get this far, it means that the page needs to be
    ** written to the transaction journal or the ckeckpoint journal
    ** or both.

        pPager->nRec++;
        assert( pPager->pInJournal!=0 );
        sqlite3BitvecSet(pPager->pInJournal, pPg->pgno);
        if( !pPager->noSync ){
          pPg->flags |= PGHDR_NEED_SYNC;
        }

        addToSavepointBitvecs(pPager, pPg->pgno);

      }else{
        if( !pPager->journalStarted && !pPager->noSync ){
          pPg->flags |= PGHDR_NEED_SYNC;
        }
        PAGERTRACE4("APPEND %d page %d needSync=%d\n",
                PAGERID(pPager), pPg->pgno,
               ((pPg->flags&PGHDR_NEED_SYNC)?1:0));
      }
      if( pPg->flags&PGHDR_NEED_SYNC ){
        pPager->needSync = 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( !pageInSavepoint(pPg) ){


      i64 offset = pPager->stmtNRec*(4+pPager->pageSize);
      char *pData2 = CODEC2(pPager, pData, pPg->pgno, 7);
      assert( pageInJournal(pPg) || pPg->pgno>pPager->origDbSize );
      rc = write32bits(pPager->sjfd, offset, pPg->pgno);
      if( rc==SQLITE_OK ){
        rc = sqlite3OsWrite(pPager->sjfd, pData2, pPager->pageSize, offset+4);
      }
      PAGERTRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
      if( rc!=SQLITE_OK ){
        return rc;
      }
      pPager->stmtNRec++;
      assert( pPager->nSavepoint>0 );
      addToSavepointBitvecs(pPager, pPg->pgno);
    }
  }

  /* Update the database size and return.
  */
  assert( pPager->state>=PAGER_SHARED );
  if( pPager->dbSize<pPg->pgno ){

    pPager->pAlwaysRollback = sqlite3BitvecCreate(pPager->origDbSize);
    if( !pPager->pAlwaysRollback ){
      return SQLITE_NOMEM;
    }
  }
  rc = sqlite3BitvecSet(pPager->pAlwaysRollback, pPg->pgno);

  if( rc==SQLITE_OK && (pPg->flags&PGHDR_DIRTY) && pPager->nSavepoint==0 ){
    assert( pPager->state>=PAGER_SHARED );
    if( pPager->dbSize==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

  ** necessarily true:
  */
  /* assert( !pPg->inJournal && (int)pPg->pgno <= pPager->origDbSize ); */

  assert( pPager->pInJournal!=0 );
  sqlite3BitvecSet(pPager->pInJournal, pPg->pgno);
  pPg->flags &= ~PGHDR_NEED_READ;


  addToSavepointBitvecs(pPager, pPg->pgno);

  PAGERTRACE3("DONT_ROLLBACK page %d of %d\n", pPg->pgno, PAGERID(pPager));
  IOTRACE(("GARBAGE %p %d\n", pPager, pPg->pgno))
}


/*
** This routine is called to increment the database file change-counter,

}
int sqlite3PagerIsMemdb(Pager *pPager){
  return MEMDB;
}
#endif

/*
** Ensure that there are at least nSavepoint savepoints open.




*/
int sqlite3PagerOpenSavepoint(Pager *pPager, int nSavepoint){
  int rc = SQLITE_OK;

  if( nSavepoint>pPager->nSavepoint ){
    int ii;

    /* Either the sub-journal is open or there are no active savepoints. */
    assert( pPager->nSavepoint==0 || pPager->sjfd->pMethods );

    /* Grow the Pager.aSavepoint array using realloc(). Return SQLITE_NOMEM
    ** if the allocation fails. Otherwise, zero the new portion in case a 
    ** malloc failure occurs while populating it in the for(...) loop below.
    */
    PagerSavepoint *aNew = (PagerSavepoint *)sqlite3Realloc(
        pPager->aSavepoint, sizeof(PagerSavepoint)*nSavepoint
    );
    if( !aNew ){
      return SQLITE_NOMEM;
    }



    memset(&aNew[pPager->nSavepoint], 0,
        (nSavepoint - pPager->nSavepoint) * sizeof(PagerSavepoint)
    );
    pPager->aSavepoint = aNew;
    ii = pPager->nSavepoint;
    pPager->nSavepoint = nSavepoint;


    /* Populate the PagerSavepoint structures just allocated. */
    for(/* no-op */; ii<nSavepoint; ii++){
      assert( pPager->dbSize>=0 );
      aNew[ii].nOrig = pPager->dbSize;
      aNew[ii].iOffset = (pPager->journalOpen ? pPager->journalOff : 0);
      aNew[ii].iSubRec = pPager->stmtNRec;

      aNew[ii].pInSavepoint = sqlite3BitvecCreate(pPager->dbSize);


      if( !aNew[ii].pInSavepoint ){

        return SQLITE_NOMEM;
      }
    }

    /* Open the sub-journal, if it is not already opened. */
    rc = openSubJournal(pPager);
  }








  return rc;
}






/*
** Parameter op is always either SAVEPOINT_ROLLBACK or SAVEPOINT_RELEASE.
** If it is SAVEPOINT_RELEASE, then release and destroy the savepoint with
** index iSavepoint. If it is SAVEPOINT_ROLLBACK, then rollback all changes
** that have occured since savepoint iSavepoint was created.
**
** In either case, all savepoints with an index greater than iSavepoint 
** are destroyed.
**
** If there are less than (iSavepoint+1) active savepoints when this 
** function is called it is a no-op.
*/ 
int sqlite3PagerSavepoint(Pager *pPager, int op, int iSavepoint){
  int rc = SQLITE_OK;

  assert( op==SAVEPOINT_RELEASE || op==SAVEPOINT_ROLLBACK );

  if( iSavepoint<pPager->nSavepoint ){
    int ii;
    int nNew = iSavepoint + (op==SAVEPOINT_ROLLBACK);
    for(ii=nNew; ii<pPager->nSavepoint; ii++){
      sqlite3BitvecDestroy(pPager->aSavepoint[ii].pInSavepoint);
    }
    pPager->nSavepoint = nNew;

    if( op==SAVEPOINT_ROLLBACK ){
      PagerSavepoint *pSavepoint = (nNew==0) ? 0 : &pPager->aSavepoint[nNew-1];
      rc = pagerPlaybackSavepoint(pPager, pSavepoint);
      assert(rc!=SQLITE_DONE);
    }

    /* If this is a release of the outermost savepoint, truncate 
    ** the sub-journal. */
    if( nNew==0 && op==SAVEPOINT_RELEASE && pPager->sjfd->pMethods ){
      assert( rc==SQLITE_OK );
      rc = sqlite3OsTruncate(pPager->sjfd, 0);
      pPager->stmtNRec = 0;



    }
  }

















  return rc;
}

/*
** Return the full pathname of the database file.
*/
const char *sqlite3PagerFilename(Pager *pPager){

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface that the sqlite page cache
** subsystem.  The page cache subsystem reads and writes a file a page
** at a time and provides a journal for rollback.
**
** @(#) $Id: pager.h,v 1.89 2008/12/17 17:30:26 danielk1977 Exp $
*/

#ifndef _PAGER_H_
#define _PAGER_H_

/*
** If defined as non-zero, auto-vacuum is enabled by default. Otherwise

void *sqlite3PagerGetExtra(DbPage *); 
int sqlite3PagerLockingMode(Pager *, int);
int sqlite3PagerJournalMode(Pager *, int);
i64 sqlite3PagerJournalSizeLimit(Pager *, i64);
void *sqlite3PagerTempSpace(Pager*);
int sqlite3PagerSync(Pager *pPager);

int sqlite3PagerOpenSavepoint(Pager *pPager, int n);
int sqlite3PagerSavepoint(Pager *pPager, int op, int iSavepoint);

#ifdef SQLITE_HAS_CODEC
  void sqlite3PagerSetCodec(Pager*,void*(*)(void*,void*,Pgno,int),void*);
#endif

#if !defined(NDEBUG) || defined(SQLITE_TEST)
  Pgno sqlite3PagerPagenumber(DbPage*);
  int sqlite3PagerIswriteable(DbPage*);

**
*************************************************************************
** This file contains SQLite's grammar for SQL.  Process this file
** using the lemon parser generator to generate C code that runs
** the parser.  Lemon will also generate a header file containing
** numeric codes for all of the tokens.
**
** @(#) $Id: parse.y,v 1.266 2008/12/17 17:30:26 danielk1977 Exp $
*/

// All token codes are small integers with #defines that begin with "TK_"
%token_prefix TK_

// The type of the data attached to each token is Token.  This is also the
// default type for non-terminals.

transtype(A) ::= .             {A = TK_DEFERRED;}
transtype(A) ::= DEFERRED(X).  {A = @X;}
transtype(A) ::= IMMEDIATE(X). {A = @X;}
transtype(A) ::= EXCLUSIVE(X). {A = @X;}
cmd ::= COMMIT trans_opt.      {sqlite3CommitTransaction(pParse);}
cmd ::= END trans_opt.         {sqlite3CommitTransaction(pParse);}
cmd ::= ROLLBACK trans_opt.    {sqlite3RollbackTransaction(pParse);}

savepoint_opt ::= SAVEPOINT.
savepoint_opt ::= .
cmd ::= SAVEPOINT nm(X). {
  sqlite3Savepoint(pParse, SAVEPOINT_BEGIN, &X);
}
cmd ::= RELEASE savepoint_opt nm(X). {
  sqlite3Savepoint(pParse, SAVEPOINT_RELEASE, &X);
}
cmd ::= ROLLBACK trans_opt TO savepoint_opt nm(X). {
  sqlite3Savepoint(pParse, SAVEPOINT_ROLLBACK, &X);
}

///////////////////// The CREATE TABLE statement ////////////////////////////
//
cmd ::= create_table create_table_args.
create_table ::= CREATE temp(T) TABLE ifnotexists(E) nm(Y) dbnm(Z). {
   sqlite3StartTable(pParse,&Y,&Z,T,0,0,E);
}

/*
** 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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.810 2008/12/17 17:30:26 danielk1977 Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Include the configuration header output by 'configure' if we're using the
** autoconf-based build

typedef struct KeyClass KeyClass;
typedef struct KeyInfo KeyInfo;
typedef struct Lookaside Lookaside;
typedef struct LookasideSlot LookasideSlot;
typedef struct Module Module;
typedef struct NameContext NameContext;
typedef struct Parse Parse;
typedef struct Savepoint Savepoint;
typedef struct Select Select;
typedef struct SrcList SrcList;
typedef struct StrAccum StrAccum;
typedef struct Table Table;
typedef struct TableLock TableLock;
typedef struct Token Token;
typedef struct TriggerStack TriggerStack;

  Hash aCollSeq;                /* All collating sequences */
  BusyHandler busyHandler;      /* Busy callback */
  int busyTimeout;              /* Busy handler timeout, in msec */
  Db aDbStatic[2];              /* Static space for the 2 default backends */
#ifdef SQLITE_SSE
  sqlite3_stmt *pFetch;         /* Used by SSE to fetch stored statements */
#endif
  Savepoint *pSavepoint;        /* List of active savepoints */
  int nSavepoint;               /* Number of non-transaction savepoints */
  u8 isTransactionSavepoint;    /* True if the outermost savepoint is a TS */
};

/*
** A macro to discover the encoding of a database.
*/
#define ENC(db) ((db)->aDb[0].pSchema->enc)

#define STR_FUNCTION(zName, nArg, pArg, bNC, xFunc) \
  {nArg, SQLITE_UTF8, bNC*8, pArg, 0, xFunc, 0, 0, #zName, 0}
#define LIKEFUNC(zName, nArg, arg, flags) \
  {nArg, SQLITE_UTF8, flags, (void *)arg, 0, likeFunc, 0, 0, #zName, 0}
#define AGGREGATE(zName, nArg, arg, nc, xStep, xFinal) \
  {nArg, SQLITE_UTF8, nc*8, SQLITE_INT_TO_PTR(arg), 0, 0, xStep,xFinal,#zName,0}

/*
** All current savepoints are stored in a linked list starting at
** sqlite3.pSavepoint. The first element in the list is the most recently
** opened savepoint. Savepoints are added to the list by the vdbe
** OP_Savepoint instruction.
*/
struct Savepoint {
  char *zName;                        /* Savepoint name (nul-terminated) */
  Savepoint *pNext;                   /* Parent savepoint (if any) */
};

/*
** The following are used as the second parameter to sqlite3Savepoint(),
** and as the P1 argument to the OP_Savepoint instruction.
*/
#define SAVEPOINT_BEGIN      0
#define SAVEPOINT_RELEASE    1
#define SAVEPOINT_ROLLBACK   2


/*
** Each SQLite module (virtual table definition) is defined by an
** instance of the following structure, stored in the sqlite3.aModule
** hash table.
*/
struct Module {

void sqlite3PrngRestoreState(void);
void sqlite3PrngResetState(void);
void sqlite3RollbackAll(sqlite3*);
void sqlite3CodeVerifySchema(Parse*, int);
void sqlite3BeginTransaction(Parse*, int);
void sqlite3CommitTransaction(Parse*);
void sqlite3RollbackTransaction(Parse*);
void sqlite3Savepoint(Parse*, int, Token*);
void sqlite3CloseSavepoints(sqlite3 *);
int sqlite3ExprIsConstant(Expr*);
int sqlite3ExprIsConstantNotJoin(Expr*);
int sqlite3ExprIsConstantOrFunction(Expr*);
int sqlite3ExprIsInteger(Expr*, int*);
int sqlite3IsRowid(const char*);
void sqlite3GenerateRowDelete(Parse*, Table*, int, int, int);
void sqlite3GenerateRowIndexDelete(Parse*, Table*, int, int*);

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the pager.c module in SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test2.c,v 1.63 2008/12/17 17:30:26 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

  int rc;
  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID\"", 0);
    return TCL_ERROR;
  }
  pPager = sqlite3TestTextToPtr(argv[1]);
  rc = sqlite3PagerOpenSavepoint(pPager, 1);
  if( rc!=SQLITE_OK ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  return TCL_OK;
}

  int rc;
  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID\"", 0);
    return TCL_ERROR;
  }
  pPager = sqlite3TestTextToPtr(argv[1]);
  rc = sqlite3PagerSavepoint(pPager, SAVEPOINT_ROLLBACK, 0);
  sqlite3PagerSavepoint(pPager, SAVEPOINT_RELEASE, 0);
  if( rc!=SQLITE_OK ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  return TCL_OK;
}

  int rc;
  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID\"", 0);
    return TCL_ERROR;
  }
  pPager = sqlite3TestTextToPtr(argv[1]);
  rc = sqlite3PagerSavepoint(pPager, SAVEPOINT_RELEASE, 0);
  if( rc!=SQLITE_OK ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  return TCL_OK;
}

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.804 2008/12/17 17:30:26 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor

  extern int sqlite3_io_error_pending;
  if( sqlite3_io_error_pending<=0 )
#endif
    rc = sqlite3OsAccess(db->pVfs, zFile, SQLITE_ACCESS_EXISTS, &res);
  return (res && rc==SQLITE_OK);
}
#endif

#ifndef NDEBUG
/*
** This function is only called from within an assert() expression. It
** checks that the sqlite3.nTransaction variable is correctly set to
** the number of non-transaction savepoints currently in the 
** linked list starting at sqlite3.pSavepoint.
** 
** Usage:
**
**     assert( checkSavepointCount(db) );
*/
static int checkSavepointCount(sqlite3 *db){
  int n = 0;
  Savepoint *p;
  for(p=db->pSavepoint; p; p=p->pNext) n++;
  assert( n==(db->nSavepoint + db->isTransactionSavepoint) );
  return 1;
}
#endif

/*
** Execute as much of a VDBE program as we can then return.
**
** sqlite3VdbeMakeReady() must be called before this routine in order to
** close the program with a final OP_Halt and to set up the callbacks
** and the error message pointer.

    if( !sqlite3BtreeIsInStmt(pBt) ){
      rc = sqlite3BtreeBeginStmt(pBt);
      p->openedStatement = 1;
    }
  }
  break;
}

/* Opcode: Savepoint P1 * * P4 *
**
** Open, release or rollback the savepoint named by parameter P4, depending
** on the value of P1. To open a new savepoint, P1==0. To release (commit) an
** existing savepoint, P1==1, or to rollback an existing savepoint P1==2.
*/
case OP_Savepoint: {
  int p1 = pOp->p1;
  char *zName = pOp->p4.z;         /* Name of savepoint */

  /* Assert that the p1 parameter is valid. Also that if there is no open
  ** transaction, then there cannot be any savepoints. 
  */
  assert( db->pSavepoint==0 || db->autoCommit==0 );
  assert( p1==SAVEPOINT_BEGIN||p1==SAVEPOINT_RELEASE||p1==SAVEPOINT_ROLLBACK );
  assert( db->pSavepoint || db->isTransactionSavepoint==0 );
  assert( checkSavepointCount(db) );

  if( p1==SAVEPOINT_BEGIN ){
    if( db->writeVdbeCnt>1 ){
      /* A new savepoint cannot be created if there are active write 
      ** statements (i.e. open read/write incremental blob handles).
      */
      sqlite3SetString(&p->zErrMsg, db, "cannot open savepoint - "
        "SQL statements in progress");
      rc = SQLITE_BUSY;
    }else{
      int nName = sqlite3Strlen30(zName);
      Savepoint *pNew;

      /* Create a new savepoint structure. */
      pNew = sqlite3DbMallocRaw(db, sizeof(Savepoint)+nName+1);
      if( pNew ){
        pNew->zName = (char *)&pNew[1];
        memcpy(pNew->zName, zName, nName+1);
    
        /* If there is no open transaction, then mark this as a special
        ** "transaction savepoint". */
        if( db->autoCommit ){
          db->autoCommit = 0;
          db->isTransactionSavepoint = 1;
        }else{
          db->nSavepoint++;
	}
    
        /* Link the new savepoint into the database handle's list. */
        pNew->pNext = db->pSavepoint;
        db->pSavepoint = pNew;
      }
    }
  }else{
    Savepoint *pSavepoint;
    int iSavepoint = 0;

    /* Find the named savepoint. If there is no such savepoint, then an
    ** an error is returned to the user.  */
    for(
      pSavepoint=db->pSavepoint; 
      pSavepoint && sqlite3StrICmp(pSavepoint->zName, zName);
      pSavepoint=pSavepoint->pNext
    ){
      iSavepoint++;
    }
    if( !pSavepoint ){
      sqlite3SetString(&p->zErrMsg, db, "no such savepoint: %s", zName);
      rc = SQLITE_ERROR;
    }else if( 
        db->writeVdbeCnt>0 || (p1==SAVEPOINT_ROLLBACK && db->activeVdbeCnt>1) 
    ){
      /* It is not possible to release (commit) a savepoint if there are 
      ** active write statements. It is not possible to rollback a savepoint
      ** if there are any active statements at all.
      */
      sqlite3SetString(&p->zErrMsg, db, 
        "cannot %s savepoint - SQL statements in progress",
        (p1==SAVEPOINT_ROLLBACK ? "rollback": "release")
      );
      rc = SQLITE_BUSY;
    }else{

      /* Determine whether or not this is a transaction savepoint. If so,
      ** operate on the currently open transaction. If this is a RELEASE 
      ** command, then the transaction is committed. If it is a ROLLBACK 
      ** command, then all changes made by the current transaction are 
      ** reverted, but the transaction is not actually closed.
      */
      int isTransaction = pSavepoint->pNext==0 && db->isTransactionSavepoint;
      if( isTransaction && p1==SAVEPOINT_RELEASE ){
        db->isTransactionSavepoint = 0;
        db->autoCommit = 1;
        if( sqlite3VdbeHalt(p)==SQLITE_BUSY ){
          p->pc = pc;
          db->autoCommit = 0;
          p->rc = rc = SQLITE_BUSY;
          goto vdbe_return;
        }
      }else{
        int ii;
        iSavepoint = db->nSavepoint - iSavepoint - 1;
        for(ii=0; ii<db->nDb; ii++){
          rc = sqlite3BtreeSavepoint(db->aDb[ii].pBt, p1, iSavepoint);
          if( rc!=SQLITE_OK ){
            goto abort_due_to_error;
	  }
        }
        if( p1==SAVEPOINT_ROLLBACK && db->flags&SQLITE_InternChanges ){
          sqlite3ExpirePreparedStatements(db);
          sqlite3ResetInternalSchema(db, 0);
        }
      }
  
      /* Regardless of whether this is a RELEASE or ROLLBACK, destroy all 
      ** savepoints nested inside of the savepoint being operated on. */
      while( db->pSavepoint!=pSavepoint ){
        Savepoint *pTmp = db->pSavepoint;
        db->pSavepoint = pTmp->pNext;
        sqlite3DbFree(db, pTmp);
        db->nSavepoint--;
      }

      /* If it is a RELEASE, then destroy the savepoint being operated on too */
      if( p1==SAVEPOINT_RELEASE ){
        assert( pSavepoint==db->pSavepoint );
        db->pSavepoint = pSavepoint->pNext;
        sqlite3DbFree(db, pSavepoint);
        if( !isTransaction ){
          db->nSavepoint--;
        }
      }
    }
  }

  break;
}

/* Opcode: AutoCommit P1 P2 * * *
**
** Set the database auto-commit flag to P1 (1 or 0). If P2 is true, roll
** back any currently active btree transactions. If there are any active
** VMs (apart from this one), then the COMMIT or ROLLBACK statement fails.
**

    /* If this instruction implements a COMMIT and other VMs are writing
    ** return an error indicating that the other VMs must complete first. 
    */
    sqlite3SetString(&p->zErrMsg, db, "cannot commit transaction - "
        "SQL statements in progress");
    rc = SQLITE_BUSY;
  }else if( desiredAutoCommit!=db->autoCommit ){
    if( rollback ){
      assert( desiredAutoCommit==1 );
      sqlite3RollbackAll(db);
      db->autoCommit = 1;
    }else{
      db->autoCommit = (u8)desiredAutoCommit;
      if( sqlite3VdbeHalt(p)==SQLITE_BUSY ){
        p->pc = pc;
        db->autoCommit = (u8)(1-desiredAutoCommit);
        p->rc = rc = SQLITE_BUSY;
        goto vdbe_return;
      }
    }
    sqlite3CloseSavepoints(db);
    if( p->rc==SQLITE_OK ){
      rc = SQLITE_DONE;
    }else{
      rc = SQLITE_ERROR;
    }
    goto vdbe_return;
  }else{

# 2008 December 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.
#
#***********************************************************************
#
# $Id: savepoint.test,v 1.1 2008/12/17 17:30:26 danielk1977 Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl


#----------------------------------------------------------------------
# The following tests - savepoint-1.* - test that the SAVEPOINT, RELEASE
# and ROLLBACK TO comands are correctly parsed, and that the auto-commit
# flag is correctly set and unset as a result.
#
do_test savepoint-1.1 {
  execsql {
    SAVEPOINT sp1;
    RELEASE sp1;
  }
} {}
do_test savepoint-1.2 {
  execsql {
    SAVEPOINT sp1;
    ROLLBACK TO sp1;
  }
} {}
do_test savepoint-1.3 {
  execsql { SAVEPOINT sp1 }
  db close
} {}
sqlite3 db test.db
do_test savepoint-1.4.1 {
  execsql {
    SAVEPOINT sp1;
    SAVEPOINT sp2;
    RELEASE sp1;
  }
  sqlite3_get_autocommit db
} {1}
do_test savepoint-1.4.2 {
  execsql {
    SAVEPOINT sp1;
    SAVEPOINT sp2;
    RELEASE sp2;
  }
  sqlite3_get_autocommit db
} {0}
do_test savepoint-1.4.3 {
  execsql { RELEASE sp1 }
  sqlite3_get_autocommit db
} {1}
do_test savepoint-1.4.4 {
  execsql {
    SAVEPOINT sp1;
    SAVEPOINT sp2;
    ROLLBACK TO sp1;
  }
  sqlite3_get_autocommit db
} {0}
do_test savepoint-1.4.5 {
  execsql { RELEASE SAVEPOINT sp1 }
  sqlite3_get_autocommit db
} {1}
do_test savepoint-1.4.6 {
  execsql {
    SAVEPOINT sp1;
    SAVEPOINT sp2;
    SAVEPOINT sp3;
    ROLLBACK TO SAVEPOINT sp3;
    ROLLBACK TRANSACTION TO sp2;
    ROLLBACK TRANSACTION TO SAVEPOINT sp1;
  }
  sqlite3_get_autocommit db
} {0}
do_test savepoint-1.4.7 {
  execsql { RELEASE SAVEPOINT SP1 }
  sqlite3_get_autocommit db
} {1}
do_test savepoint-1.5 {
  execsql {
    SAVEPOINT sp1;
    ROLLBACK TO sp1;
  }
} {}
do_test savepoint-1.6 {
  execsql COMMIT
} {}

#------------------------------------------------------------------------
# These tests - savepoint-2.* - test rollbacks and releases of savepoints
# with a very simple data set.
# 

do_test savepoint-2.1 {
  execsql {
    CREATE TABLE t1(a, b, c);
    BEGIN;
    INSERT INTO t1 VALUES(1, 2, 3);
    SAVEPOINT one;
    UPDATE t1 SET a = 2, b = 3, c = 4;
  }
  execsql { SELECT * FROM t1 }
} {2 3 4}
do_test savepoint-2.2 {
  execsql {
    ROLLBACK TO one;
  }
  execsql { SELECT * FROM t1 }
} {1 2 3}
do_test savepoint-2.3 {
  execsql {
    INSERT INTO t1 VALUES(4, 5, 6);
  }
  execsql { SELECT * FROM t1 }
} {1 2 3 4 5 6}
do_test savepoint-2.4 {
  execsql {
    ROLLBACK TO one;
  }
  execsql { SELECT * FROM t1 }
} {1 2 3}


do_test savepoint-2.5 {
  execsql {
    INSERT INTO t1 VALUES(7, 8, 9);
    SAVEPOINT two;
    INSERT INTO t1 VALUES(10, 11, 12);
  }
  execsql { SELECT * FROM t1 }
} {1 2 3 7 8 9 10 11 12}
do_test savepoint-2.6 {
  execsql {
    ROLLBACK TO two;
  }
  execsql { SELECT * FROM t1 }
} {1 2 3 7 8 9}
do_test savepoint-2.7 {
  execsql {
    INSERT INTO t1 VALUES(10, 11, 12);
  }
  execsql { SELECT * FROM t1 }
} {1 2 3 7 8 9 10 11 12}
do_test savepoint-2.8 {
  execsql {
    ROLLBACK TO one;
  }
  execsql { SELECT * FROM t1 }
} {1 2 3}
do_test savepoint-2.9 {
  execsql {
    INSERT INTO t1 VALUES('a', 'b', 'c');
    SAVEPOINT two;
    INSERT INTO t1 VALUES('d', 'e', 'f');
  }
  execsql { SELECT * FROM t1 }
} {1 2 3 a b c d e f}
do_test savepoint-2.10 {
  execsql {
    RELEASE two;
  }
  execsql { SELECT * FROM t1 }
} {1 2 3 a b c d e f}
do_test savepoint-2.11 {
  execsql {
    ROLLBACK;
  }
  execsql { SELECT * FROM t1 }
} {}

#------------------------------------------------------------------------
# This block of tests - savepoint-3.* - test that when a transaction
# savepoint is rolled back, locks are not released from database files.
# And that when a transaction savepoint is released, they are released.
# 
do_test savepoint-3.1 {
  execsql { SAVEPOINT "transaction" }
  execsql { PRAGMA lock_status }
} {main unlocked temp closed}

do_test savepoint-3.2 {
  execsql { INSERT INTO t1 VALUES(1, 2, 3) }
  execsql { PRAGMA lock_status }
} {main reserved temp closed}

do_test savepoint-3.3 {
  execsql { ROLLBACK TO "transaction" }
  execsql { PRAGMA lock_status }
} {main reserved temp closed}

do_test savepoint-3.4 {
  execsql { INSERT INTO t1 VALUES(1, 2, 3) }
  execsql { PRAGMA lock_status }
} {main reserved temp closed}

do_test savepoint-3.5 {
  execsql { RELEASE "transaction" }
  execsql { PRAGMA lock_status }
} {main unlocked temp closed}

#------------------------------------------------------------------------
# Test that savepoints that include schema modifications are handled
# correctly. Test cases savepoint-4.*.
# 
do_test savepoint-4.1 {
  execsql {
    CREATE TABLE t2(d, e, f);
    SELECT sql FROM sqlite_master;
  }
} {{CREATE TABLE t1(a, b, c)} {CREATE TABLE t2(d, e, f)}}
do_test savepoint-4.2 {
  execsql {
    BEGIN;
    CREATE TABLE t3(g,h);
    INSERT INTO t3 VALUES('I', 'II');
    SAVEPOINT one;
    DROP TABLE t3;
  }
} {}
do_test savepoint-4.3 {
  execsql {
    CREATE TABLE t3(g, h, i);
    INSERT INTO t3 VALUES('III', 'IV', 'V');
  }
  execsql {SELECT * FROM t3}
} {III IV V}
do_test savepoint-4.4 {
  execsql { ROLLBACK TO one; }
  execsql {SELECT * FROM t3}
} {I II}
do_test savepoint-4.5 {
  execsql {
    ROLLBACK;
    SELECT sql FROM sqlite_master;
  }
} {{CREATE TABLE t1(a, b, c)} {CREATE TABLE t2(d, e, f)}}

do_test savepoint-4.6 {
  execsql {
    BEGIN;
    INSERT INTO t1 VALUES('o', 't', 't');
    SAVEPOINT sp1;
    CREATE TABLE t3(a, b, c);
    INSERT INTO t3 VALUES('z', 'y', 'x');
  }
  execsql {SELECT * FROM t3}
} {z y x}
do_test savepoint-4.7 {
  execsql {
    ROLLBACK TO sp1;
    CREATE TABLE t3(a);
    INSERT INTO t3 VALUES('value');
  }
  execsql {SELECT * FROM t3}
} {value}
do_test savepoint-4.8 {
  execsql COMMIT
} {}

finish_test

** A header comment placed at the beginning of generated code.
*/
static const char zHdr[] = 
  "/***** This file contains automatically generated code ******\n"
  "**\n"
  "** The code in this file has been automatically generated by\n"
  "**\n"
  "**     $Header: /home/drh/sqlite/trans/cvs/sqlite/sqlite/tool/mkkeywordhash.c,v 1.35 2008/12/17 17:30:26 danielk1977 Exp $\n"
  "**\n"
  "** The code in this file implements a function that determines whether\n"
  "** or not a given identifier is really an SQL keyword.  The same thing\n"
  "** might be implemented more directly using a hand-written hash table.\n"
  "** But by using this automatically generated code, the size of the code\n"
  "** is substantially reduced.  This is important for embedded applications\n"
  "** on platforms with limited memory.\n"

  { "PRAGMA",           "TK_PRAGMA",       PRAGMA                 },
  { "PRIMARY",          "TK_PRIMARY",      ALWAYS                 },
  { "QUERY",            "TK_QUERY",        EXPLAIN                },
  { "RAISE",            "TK_RAISE",        TRIGGER                },
  { "REFERENCES",       "TK_REFERENCES",   FKEY                   },
  { "REGEXP",           "TK_LIKE_KW",      ALWAYS                 },
  { "REINDEX",          "TK_REINDEX",      REINDEX                },
  { "RELEASE",          "TK_RELEASE",      ALWAYS                 },
  { "RENAME",           "TK_RENAME",       ALTER                  },
  { "REPLACE",          "TK_REPLACE",      CONFLICT               },
  { "RESTRICT",         "TK_RESTRICT",     FKEY                   },
  { "RIGHT",            "TK_JOIN_KW",      ALWAYS                 },
  { "ROLLBACK",         "TK_ROLLBACK",     ALWAYS                 },
  { "ROW",              "TK_ROW",          TRIGGER                },
  { "SAVEPOINT",        "TK_SAVEPOINT",    ALWAYS                 },
  { "SELECT",           "TK_SELECT",       ALWAYS                 },
  { "SET",              "TK_SET",          ALWAYS                 },
  { "TABLE",            "TK_TABLE",        ALWAYS                 },
  { "TEMP",             "TK_TEMP",         ALWAYS                 },
  { "TEMPORARY",        "TK_TEMP",         ALWAYS                 },
  { "THEN",             "TK_THEN",         ALWAYS                 },
  { "TO",               "TK_TO",           ALTER                  },