Fossil

/*
** Mark artifact rid as being available now.  Update the cache to
** show that everything that was formerly unavailable because rid
** was missing is now available.
*/
static void content_mark_available(int rid){
  Bag pending;
  Stmt q;
  if( bag_find(&contentCache.available, rid) ) return;
  bag_init(&pending);
  bag_insert(&pending, rid);
  while( (rid = bag_first(&pending))!=0 ){
    bag_remove(&pending, rid);
    bag_remove(&contentCache.missing, rid);
    bag_insert(&contentCache.available, rid);
    db_prepare(&q, "SELECT rid FROM delta WHERE srcid=%d", rid);

    while( db_step(&q)==SQLITE_ROW ){
      int nx = db_column_int(&q, 0);
      bag_insert(&pending, nx);
    }
    db_finalize(&q);
  }
  bag_clear(&pending);
}

/*
** Get the blob.content value for blob.rid=rid.  Return 1 on success or
** 0 on failure.
................................................................................
/*
** When a record is converted from a phantom to a real record,
** if that record has other records that are derived by delta,
** then call manifest_crosslink() on those other records.
*/
void after_dephantomize(int rid, int linkFlag){
  Stmt q;








  db_prepare(&q, "SELECT rid FROM delta WHERE srcid=%d", rid);
  while( db_step(&q)==SQLITE_ROW ){
    int tid = db_column_int(&q, 0);
    after_dephantomize(tid, 1);

  }
  db_finalize(&q);

  if( linkFlag ){
    Blob content;
    content_get(rid, &content);
    manifest_crosslink(rid, &content);
    blob_reset(&content);
  }
}

/*
** Mark artifact rid as being available now.  Update the cache to
** show that everything that was formerly unavailable because rid
** was missing is now available.
*/
static void content_mark_available(int rid){
  Bag pending;
  static Stmt q;
  if( bag_find(&contentCache.available, rid) ) return;
  bag_init(&pending);
  bag_insert(&pending, rid);
  while( (rid = bag_first(&pending))!=0 ){
    bag_remove(&pending, rid);
    bag_remove(&contentCache.missing, rid);
    bag_insert(&contentCache.available, rid);
    db_static_prepare(&q, "SELECT rid FROM delta WHERE srcid=:rid");
    db_bind_int(&q, ":rid", rid);
    while( db_step(&q)==SQLITE_ROW ){
      int nx = db_column_int(&q, 0);
      bag_insert(&pending, nx);
    }
    db_reset(&q);
  }
  bag_clear(&pending);
}

/*
** Get the blob.content value for blob.rid=rid.  Return 1 on success or
** 0 on failure.
................................................................................
/*
** When a record is converted from a phantom to a real record,
** if that record has other records that are derived by delta,
** then call manifest_crosslink() on those other records.
*/
void after_dephantomize(int rid, int linkFlag){
  Stmt q;
  int prevTid = 0;

  /* The prevTid variable is used to delay invoking this routine
  ** recursively, if possible, until after the query has finalized,
  ** in order to avoid having an excessive number of prepared statements.
  ** This is most effective in the common case where the query returns 
  ** just one row.
  */
  db_prepare(&q, "SELECT rid FROM delta WHERE srcid=%d", rid);
  while( db_step(&q)==SQLITE_ROW ){
    int tid = db_column_int(&q, 0);
    if( prevTid ) after_dephantomize(prevTid, 1);
    prevTid = tid;
  }
  db_finalize(&q);
  if( prevTid ) after_dephantomize(prevTid, 1);
  if( linkFlag ){
    Blob content;
    content_get(rid, &content);
    manifest_crosslink(rid, &content);
    blob_reset(&content);
  }
}

** With a value argument it changes the property for the current repository.
**
** The "unset" command clears a property setting.
**
**
**    auto-captcha     If enabled, the Login page provides a button to
**                     fill in the captcha password.  Default: on



**
**    autosync         If enabled, automatically pull prior to commit
**                     or update and automatically push after commit or
**                     tag or branch creation.  If the the value is "pullonly"
**                     then only pull operations occur automatically.
**
**    binary-glob      The VALUE is a comma-separated list of GLOB patterns
................................................................................
**                     web browser when given a URL as an argument.
**                     Defaults to "start" on windows, "open" on Mac,
**                     and "firefox" on Unix.
*/
void setting_cmd(void){
  static const char *azName[] = {
    "auto-captcha",

    "autosync",
    "binary-glob",
    "clearsign",
    "diff-command",
    "dont-push",
    "editor",
    "gdiff-command",

** With a value argument it changes the property for the current repository.
**
** The "unset" command clears a property setting.
**
**
**    auto-captcha     If enabled, the Login page provides a button to
**                     fill in the captcha password.  Default: on
**
**    auto-shun        If enabled, automatically pull the shunning list
**                     from a server to which the client autosyncs.
**
**    autosync         If enabled, automatically pull prior to commit
**                     or update and automatically push after commit or
**                     tag or branch creation.  If the the value is "pullonly"
**                     then only pull operations occur automatically.
**
**    binary-glob      The VALUE is a comma-separated list of GLOB patterns
................................................................................
**                     web browser when given a URL as an argument.
**                     Defaults to "start" on windows, "open" on Mac,
**                     and "firefox" on Unix.
*/
void setting_cmd(void){
  static const char *azName[] = {
    "auto-captcha",
    "auto-shun",
    "autosync",
    "binary-glob",
    "clearsign",
    "diff-command",
    "dont-push",
    "editor",
    "gdiff-command",

**     *  Does not contain any of these characters in the path: "\*[]?"
**     *  Does not end with "/".
**     *  Does not contain two or more "/" characters in a row.
**     *  Contains at least one character
*/
int file_is_simple_pathname(const char *z){
  int i;

  if( *z=='/' || *z==0 ) return 0;
  if( *z=='.' ){
    if( z[1]=='/' || z[1]==0 ) return 0;
    if( z[1]=='.' && (z[2]=='/' || z[2]==0) ) return 0;
  }
  for(i=0; z[i]; i++){
    if( z[i]=='\\' || z[i]=='*' || z[i]=='[' || z[i]==']' || z[i]=='?' ){
      return 0;
    }
    if( z[i]=='/' ){
      if( z[i+1]=='/' ) return 0;
      if( z[i+1]=='.' ){
        if( z[i+2]=='/' || z[i+2]==0 ) return 0;
        if( z[i+2]=='.' && (z[i+3]=='/' || z[i+3]==0) ) return 0;
      }
    }
  }

**     *  Does not contain any of these characters in the path: "\*[]?"
**     *  Does not end with "/".
**     *  Does not contain two or more "/" characters in a row.
**     *  Contains at least one character
*/
int file_is_simple_pathname(const char *z){
  int i;
  char c = z[0];
  if( c=='/' || c==0 ) return 0;
  if( c=='.' ){
    if( z[1]=='/' || z[1]==0 ) return 0;
    if( z[1]=='.' && (z[2]=='/' || z[2]==0) ) return 0;
  }
  for(i=0; (c=z[i])!=0; i++){
    if( c=='\\' || c=='*' || c=='[' || c==']' || c=='?' ){
      return 0;
    }
    if( c=='/' ){
      if( z[i+1]=='/' ) return 0;
      if( z[i+1]=='.' ){
        if( z[i+2]=='/' || z[i+2]==0 ) return 0;
        if( z[i+2]=='.' && (z[i+3]=='/' || z[i+3]==0) ) return 0;
      }
    }
  }

/*
** Rebuild cross-referencing information for the artifact
** rid with content pBase and all of its descendants.  This
** routine clears the content buffer before returning.
*/
static void rebuild_step(int rid, int size, Blob *pBase){
  Stmt q1;
  Bag children;
  Blob copy;
  Blob *pUse;
  int nChild, i, cid;

  /* Fix up the "blob.size" field if needed. */
  if( size!=blob_size(pBase) ){
    db_multi_exec(
       "UPDATE blob SET size=%d WHERE rid=%d", blob_size(pBase), rid
    );
  }

  /* Find all children of artifact rid */
  db_prepare(&q1, "SELECT rid FROM delta WHERE srcid=%d", rid);

  bag_init(&children);
  while( db_step(&q1)==SQLITE_ROW ){
    int cid = db_column_int(&q1, 0);
    if( !bag_find(&bagDone, cid) ){
      bag_insert(&children, cid);
    }
  }
  nChild = bag_count(&children);
  db_finalize(&q1);

  /* Crosslink the artifact */
  if( nChild==0 ){
    pUse = pBase;
  }else{
    blob_copy(&copy, pBase);
    pUse = ©
................................................................................
  if (!g.fQuiet) {
    printf("0 (0%%)...\r");
    fflush(stdout);
  }
  db_multi_exec(zSchemaUpdates);
  for(;;){
    zTable = db_text(0,
       "SELECT name FROM sqlite_master"
       " WHERE type='table'"
       " AND name NOT IN ('blob','delta','rcvfrom','user',"
                         "'config','shun','private','reportfmt',"
                         "'concealed')"
       " AND name NOT GLOB 'sqlite_*'"
    );
    if( zTable==0 ) break;
................................................................................
     " WHERE rid IN (SELECT rid FROM shun JOIN blob USING(uuid))"
  );
  db_multi_exec(
    "DELETE FROM config WHERE name IN ('remote-code', 'remote-maxid')"
  );
  totalSize = db_int(0, "SELECT count(*) FROM blob");
  db_prepare(&s,
     "SELECT rid, size FROM blob"
     " WHERE NOT EXISTS(SELECT 1 FROM shun WHERE uuid=blob.uuid)"
     "   AND NOT EXISTS(SELECT 1 FROM delta WHERE rid=blob.rid)"
  );
  manifest_crosslink_begin();
  while( db_step(&s)==SQLITE_ROW ){
    int rid = db_column_int(&s, 0);
    int size = db_column_int(&s, 1);

/*
** Rebuild cross-referencing information for the artifact
** rid with content pBase and all of its descendants.  This
** routine clears the content buffer before returning.
*/
static void rebuild_step(int rid, int size, Blob *pBase){
  static Stmt q1;
  Bag children;
  Blob copy;
  Blob *pUse;
  int nChild, i, cid;

  /* Fix up the "blob.size" field if needed. */
  if( size!=blob_size(pBase) ){
    db_multi_exec(
       "UPDATE blob SET size=%d WHERE rid=%d", blob_size(pBase), rid
    );
  }

  /* Find all children of artifact rid */
  db_static_prepare(&q1, "SELECT rid FROM delta WHERE srcid=:rid");
  db_bind_int(&q1, ":rid", rid);
  bag_init(&children);
  while( db_step(&q1)==SQLITE_ROW ){
    int cid = db_column_int(&q1, 0);
    if( !bag_find(&bagDone, cid) ){
      bag_insert(&children, cid);
    }
  }
  nChild = bag_count(&children);
  db_reset(&q1);

  /* Crosslink the artifact */
  if( nChild==0 ){
    pUse = pBase;
  }else{
    blob_copy(&copy, pBase);
    pUse = ©
................................................................................
  if (!g.fQuiet) {
    printf("0 (0%%)...\r");
    fflush(stdout);
  }
  db_multi_exec(zSchemaUpdates);
  for(;;){
    zTable = db_text(0,
       "SELECT name FROM sqlite_master /*scan*/"
       " WHERE type='table'"
       " AND name NOT IN ('blob','delta','rcvfrom','user',"
                         "'config','shun','private','reportfmt',"
                         "'concealed')"
       " AND name NOT GLOB 'sqlite_*'"
    );
    if( zTable==0 ) break;
................................................................................
     " WHERE rid IN (SELECT rid FROM shun JOIN blob USING(uuid))"
  );
  db_multi_exec(
    "DELETE FROM config WHERE name IN ('remote-code', 'remote-maxid')"
  );
  totalSize = db_int(0, "SELECT count(*) FROM blob");
  db_prepare(&s,
     "SELECT rid, size FROM blob /*scan*/"
     " WHERE NOT EXISTS(SELECT 1 FROM shun WHERE uuid=blob.uuid)"
     "   AND NOT EXISTS(SELECT 1 FROM delta WHERE rid=blob.rid)"
  );
  manifest_crosslink_begin();
  while( db_step(&s)==SQLITE_ROW ){
    int rid = db_column_int(&s, 0);
    int size = db_column_int(&s, 1);

**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.7.0"
#define SQLITE_VERSION_NUMBER 3007000
#define SQLITE_SOURCE_ID      "2010-06-26 20:25:31 f149b498b6ada3fc9f71ee104c351554c80c7f8a"

/*
** CAPI3REF: Run-Time Library Version Numbers
** KEYWORDS: sqlite3_version, sqlite3_sourceid
**
** These interfaces provide the same information as the [SQLITE_VERSION],
** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
................................................................................
**     sqlite3OsOpen()
**     sqlite3OsRead()
**     sqlite3OsWrite()
**     sqlite3OsSync()
**     sqlite3OsLock()
**
*/
#if defined(SQLITE_TEST) && (SQLITE_OS_WIN==0)

  #define DO_OS_MALLOC_TEST(x) if (!x || !sqlite3IsMemJournal(x)) {     \

    void *pTstAlloc = sqlite3Malloc(10);                             \
    if (!pTstAlloc) return SQLITE_IOERR_NOMEM;                       \
    sqlite3_free(pTstAlloc);                                         \
  }
#else
  #define DO_OS_MALLOC_TEST(x)
#endif
................................................................................
/*
** Stub routines for all mutex methods.
**
** This routines provide no mutual exclusion or error checking.
*/
static int noopMutexInit(void){ return SQLITE_OK; }
static int noopMutexEnd(void){ return SQLITE_OK; }
static sqlite3_mutex *noopMutexAlloc(int id){ return (sqlite3_mutex*)8; }



static void noopMutexFree(sqlite3_mutex *p){ return; }
static void noopMutexEnter(sqlite3_mutex *p){ return; }
static int noopMutexTry(sqlite3_mutex *p){ return SQLITE_OK; }



static void noopMutexLeave(sqlite3_mutex *p){ return; }

SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3NoopMutex(void){
  static const sqlite3_mutex_methods sMutex = {
    noopMutexInit,
    noopMutexEnd,
    noopMutexAlloc,
    noopMutexFree,
................................................................................

/*
** If compiled with SQLITE_MUTEX_NOOP, then the no-op mutex implementation
** is used regardless of the run-time threadsafety setting.
*/
#ifdef SQLITE_MUTEX_NOOP
SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3DefaultMutex(void){
  return sqliteNoopMutex();
}
#endif /* SQLITE_MUTEX_NOOP */
#endif /* SQLITE_MUTEX_OMIT */

/************** End of mutex_noop.c ******************************************/
/************** Begin file mutex_os2.c ***************************************/
/*
................................................................................
**
** All loads and stores begun before the barrier must complete before
** any load or store begun after the barrier.
*/
static void unixShmBarrier(
  sqlite3_file *fd                /* Database file holding the shared memory */
){

  unixEnterMutex();
  unixLeaveMutex();
}

/*
** This function is called to obtain a pointer to region iRegion of the 
** shared-memory associated with the database file fd. Shared-memory regions 
................................................................................
/*
** Find the current time (in Universal Coordinated Time).  Write the
** current time and date as a Julian Day number into *prNow and
** return 0.  Return 1 if the time and date cannot be found.
*/
static int unixCurrentTime(sqlite3_vfs *NotUsed, double *prNow){
  sqlite3_int64 i;

  unixCurrentTimeInt64(0, &i);
  *prNow = i/86400000.0;
  return 0;
}

/*
** We added the xGetLastError() method with the intention of providing
................................................................................

  if( lPath[len-1]!='/' ){
    len = strlcat(lPath, "/", maxLen);
  }
  
  /* transform the db path to a unique cache name */
  dbLen = (int)strlen(dbPath);
  for( i=0; i<dbLen && (i+len+7)<maxLen; i++){
    char c = dbPath[i];
    lPath[i+len] = (c=='/')?'_':c;
  }
  lPath[i+len]='\0';
  strlcat(lPath, ":auto:", maxLen);
  OSTRACE(("GETLOCKPATH  proxy lock path=%s pid=%d\n", lPath, getpid()));
  return SQLITE_OK;
................................................................................
#ifdef SQLITE_TEST
/* simulate multiple hosts by creating unique hostid file paths */
SQLITE_API int sqlite3_hostid_num = 0;
#endif

#define PROXY_HOSTIDLEN    16  /* conch file host id length */




/* get the host ID via gethostuuid(), pHostID must point to PROXY_HOSTIDLEN 
** bytes of writable memory.
*/
static int proxyGetHostID(unsigned char *pHostID, int *pError){
  struct timespec timeout = {1, 0}; /* 1 sec timeout */
  
  assert(PROXY_HOSTIDLEN == sizeof(uuid_t));
................................................................................
  char buf[PROXY_MAXCONCHLEN];
  char *cPath = pCtx->conchFilePath;
  size_t readLen = 0;
  size_t pathLen = 0;
  char errmsg[64] = "";
  int fd = -1;
  int rc = -1;


  /* create a new path by replace the trailing '-conch' with '-break' */
  pathLen = strlcpy(tPath, cPath, MAXPATHLEN);
  if( pathLen>MAXPATHLEN || pathLen<6 || 
     (strlcpy(&tPath[pathLen-5], "break", 6) != 5) ){
    sprintf(errmsg, "path error (len %d)", (int)pathLen);
    goto end_breaklock;
................................................................................
  }
  /* write it out to the temporary break file */
  fd = open(tPath, (O_RDWR|O_CREAT|O_EXCL), SQLITE_DEFAULT_FILE_PERMISSIONS);
  if( fd<0 ){
    sprintf(errmsg, "create failed (%d)", errno);
    goto end_breaklock;
  }
  if( pwrite(fd, buf, readLen, 0) != readLen ){
    sprintf(errmsg, "write failed (%d)", errno);
    goto end_breaklock;
  }
  if( rename(tPath, cPath) ){
    sprintf(errmsg, "rename failed (%d)", errno);
    goto end_breaklock;
  }
................................................................................
    }

    /* Check to see if another process is holding the dead-man switch.
    ** If not, truncate the file to zero length. 
    */
    if( winShmSystemLock(pShmNode, _SHM_WRLCK, WIN_SHM_DMS, 1)==SQLITE_OK ){
      rc = winTruncate((sqlite3_file *)&pShmNode->hFile, 0);



    }
    if( rc==SQLITE_OK ){
      winShmSystemLock(pShmNode, _SHM_UNLCK, WIN_SHM_DMS, 1);
      rc = winShmSystemLock(pShmNode, _SHM_RDLCK, WIN_SHM_DMS, 1);
    }
    if( rc ) goto shm_open_err;
  }
................................................................................
**
** All loads and stores begun before the barrier must complete before
** any load or store begun after the barrier.
*/
static void winShmBarrier(
  sqlite3_file *fd          /* Database holding the shared memory */
){

  /* MemoryBarrier(); // does not work -- do not know why not */
  winShmEnterMutex();
  winShmLeaveMutex();
}

#else
# define winShmOpen    0
................................................................................
# define sqlite3WalOpen(x,y,z)                 0
# define sqlite3WalClose(w,x,y,z)              0
# define sqlite3WalBeginReadTransaction(y,z)   0
# define sqlite3WalEndReadTransaction(z)
# define sqlite3WalRead(v,w,x,y,z)             0
# define sqlite3WalDbsize(y,z)
# define sqlite3WalBeginWriteTransaction(y)    0
# define sqlite3WalEndWRiteTransaction(x)      0
# define sqlite3WalUndo(x,y,z)                 0
# define sqlite3WalSavepoint(y,z)
# define sqlite3WalSavepointUndo(y,z)          0
# define sqlite3WalFrames(u,v,w,x,y,z)         0
# define sqlite3WalCheckpoint(u,v,w,x)         0
# define sqlite3WalCallback(z)                 0

#else

#define WAL_SAVEPOINT_NDATA 4

/* Connection to a write-ahead log (WAL) file. 
** There is one object of this type for each pager. 
*/
................................................................................
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 */

  u32 aWalData[WAL_SAVEPOINT_NDATA];        /* WAL savepoint context */

};

/*
** A open page cache is an instance of the following structure.
**
** errCode
**
................................................................................
  }
  pPager->state = PAGER_SHARED;

  return rc;
}

/*

** Check if the *-wal file that corresponds to the database opened by pPager

** exists. Assuming no error occurs, set *pExists to 1 if the file exists,





** or 0 otherwise and return SQLITE_OK. If an IO or OOM error occurs, return
** an SQLite error code.
*/
static int pagerHasWAL(Pager *pPager, int *pExists){
  int rc;                         /* Return code */
  char *zWal;                     /* Name of the WAL file */

  assert( !pPager->tempFile );
  zWal = sqlite3_mprintf("%s-wal", pPager->zFilename);
  if( !zWal ){
    rc = SQLITE_NOMEM;
  }else{

    rc = sqlite3OsAccess(pPager->pVfs, zWal, SQLITE_ACCESS_EXISTS, pExists);



    sqlite3_free(zWal);
  }
  return rc;
}

/*
** Check if the *-wal file that corresponds to the database opened by pPager
** exists. If it does, open the pager in WAL mode. Otherwise, if no error




** occurs, make sure Pager.journalMode is not set to PAGER_JOURNALMODE_WAL.
** If an IO or OOM error occurs, return an SQLite error code.



**
** If the WAL file is opened, also open a snapshot (read transaction).
**
** The caller must hold a SHARED lock on the database file to call this
** function. Because an EXCLUSIVE lock on the db file is required to delete 
** a WAL, this ensures there is no race condition between the xAccess() 
** below and an xDelete() being executed by some other connection.

*/
static int pagerOpenWalIfPresent(Pager *pPager){
  int rc = SQLITE_OK;
  if( !pPager->tempFile ){
    int isWal;                    /* True if WAL file exists */








    rc = pagerHasWAL(pPager, &isWal);

    if( rc==SQLITE_OK ){
      if( isWal ){
        pager_reset(pPager);
        rc = sqlite3PagerOpenWal(pPager, 0);
        if( rc==SQLITE_OK ){
          rc = pagerBeginReadTransaction(pPager);
        }
................................................................................
SQLITE_PRIVATE int sqlite3PagerMaxPageCount(Pager *pPager, int mxPage){
  int nPage;
  if( mxPage>0 ){
    pPager->mxPgno = mxPage;
  }
  if( pPager->state!=PAGER_UNLOCK ){
    sqlite3PagerPagecount(pPager, &nPage);
    assert( pPager->mxPgno>=nPage );
  }
  return pPager->mxPgno;
}

/*
** The following set of routines are used to disable the simulated
** I/O error mechanism.  These routines are used to avoid simulated
................................................................................
      ** other bytes change randomly with each file change when
      ** a codec is in use.
      ** 
      ** There is a vanishingly small chance that a change will not be 
      ** detected.  The chance of an undetected change is so small that
      ** it can be neglected.
      */
      int nPage;
      char dbFileVers[sizeof(pPager->dbFileVers)];
      sqlite3PagerPagecount(pPager, &nPage);

      if( pPager->errCode ){
        rc = pPager->errCode;
        goto failed;
      }
................................................................................
    }

    /* No need to open the journal file at this time.  It will be
    ** opened before it is written to.  If we defer opening the journal,
    ** we might save the work of creating a file if the transaction
    ** ends up being a no-op.
    */
  }else if( isOpen(pPager->jfd) && pPager->journalOff==0 ){
    /* This happens when the pager was in exclusive-access mode the last
    ** time a (read or write) transaction was successfully concluded
    ** by this connection. Instead of deleting the journal file it was 
    ** kept open and either was truncated to 0 bytes or its header was
    ** overwritten with zeros.
    */
    assert( pagerUseWal(pPager)==0 );
    assert( pPager->nRec==0 );
    assert( pPager->dbOrigSize==0 );
    assert( pPager->pInJournal==0 );
    rc = pager_open_journal(pPager);
  }

  PAGERTRACE(("TRANSACTION %d\n", PAGERID(pPager)));
  if( rc!=SQLITE_OK ){
    assert( !pPager->dbModified );
    /* Ignore any IO error that occurs within pager_end_transaction(). The
    ** purpose of this call is to reset the internal state of the pager
    ** sub-system. It doesn't matter if the journal-file is not properly
    ** finalized at this point (since it is not a valid journal file anyway).
    */
    pager_end_transaction(pPager, 0);
  }



  return rc;
}

/*
** Mark a single data page as writeable. The page is written into the 
** main journal or sub-journal as required. If the page is written into
** one of the journals, the corresponding bit is set in the 
................................................................................
    ** written to the transaction journal or the ckeckpoint journal
    ** or both.
    **
    ** Higher level routines should have already started a transaction,
    ** which means they have acquired the necessary locks but the rollback
    ** journal might not yet be open.
    */
    rc = sqlite3PagerBegin(pPager, 0, pPager->subjInMemory);
    if( rc!=SQLITE_OK ){
      return rc;
    }
    if( pPager->pInJournal==0
     && pPager->journalMode!=PAGER_JOURNALMODE_OFF 
     && !pagerUseWal(pPager)
    ){
      assert( pPager->useJournal );
      rc = pager_open_journal(pPager);
      if( rc!=SQLITE_OK ) return rc;
................................................................................
      ** Otherwise, if the optimization is both enabled and applicable,
      ** then call pager_incr_changecounter() to update the change-counter
      ** in 'direct' mode. In this case the journal file will never be
      ** created for this transaction.
      */
  #ifdef SQLITE_ENABLE_ATOMIC_WRITE
      PgHdr *pPg;

      assert( isOpen(pPager->jfd) || pPager->journalMode==PAGER_JOURNALMODE_OFF );


      if( !zMaster && isOpen(pPager->jfd) 
       && pPager->journalOff==jrnlBufferSize(pPager) 
       && pPager->dbSize>=pPager->dbFileSize
       && (0==(pPg = sqlite3PcacheDirtyList(pPager->pPCache)) || 0==pPg->pDirty)
      ){
        /* Update the db file change counter via the direct-write method. The 
        ** following call will modify the in-memory representation of page 1 
................................................................................
  if( NEVER(pPager->errCode) ) return pPager->errCode;

  /* This function should not be called if the pager is not in at least
  ** PAGER_RESERVED state. **FIXME**: Make it so that this test always
  ** fails - make it so that we never reach this point if we do not hold
  ** all necessary locks.
  */
  if( pPager->state<PAGER_RESERVED ) return SQLITE_ERROR;

  /* An optimization. If the database was not actually modified during
  ** this transaction, the pager is running in exclusive-mode and is
  ** using persistent journals, then this function is a no-op.
  **
  ** The start of the journal file currently contains a single journal 
  ** header with the nRec field set to 0. If such a journal is used as
................................................................................
  ** to the database file. So there is no need to zero the journal 
  ** header. Since the pager is in exclusive mode, there is no need
  ** to drop any locks either.
  */
  if( pPager->dbModified==0 && pPager->exclusiveMode 
   && pPager->journalMode==PAGER_JOURNALMODE_PERSIST
  ){
    assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) );
    return SQLITE_OK;
  }

  PAGERTRACE(("COMMIT %d\n", PAGERID(pPager)));
  assert( pPager->state==PAGER_SYNCED || MEMDB || !pPager->dbModified );
  rc = pager_end_transaction(pPager, pPager->setMaster);
  return pager_error(pPager, rc);
................................................................................
  return pPager->noSync;
}

#ifdef SQLITE_HAS_CODEC
/*
** Set or retrieve the codec for this pager
*/
static void sqlite3PagerSetCodec(
  Pager *pPager,
  void *(*xCodec)(void*,void*,Pgno,int),
  void (*xCodecSizeChng)(void*,int,int),
  void (*xCodecFree)(void*),
  void *pCodec
){
  if( pPager->xCodecFree ) pPager->xCodecFree(pPager->pCodec);
  pPager->xCodec = pPager->memDb ? 0 : xCodec;
  pPager->xCodecSizeChng = xCodecSizeChng;
  pPager->xCodecFree = xCodecFree;
  pPager->pCodec = pCodec;
  pagerReportSize(pPager);
}
static void *sqlite3PagerGetCodec(Pager *pPager){
  return pPager->pCodec;
}
#endif

#ifndef SQLITE_OMIT_AUTOVACUUM
/*
** Move the page pPg to location pgno in the file.
................................................................................
/*
** Return TRUE if the pager is in a state where it is OK to change the
** journalmode.  Journalmode changes can only happen when the database
** is unmodified.
*/
SQLITE_PRIVATE int sqlite3PagerOkToChangeJournalMode(Pager *pPager){
  if( pPager->dbModified ) return 0;
  if( isOpen(pPager->jfd) && pPager->journalOff>0 ) return 0;
  return 1;
}

/*
** Get/set the size-limit used for persistent journal files.
**
** Setting the size limit to -1 means no limit is enforced.
................................................................................
*/
SQLITE_PRIVATE int sqlite3PagerWalSupported(Pager *pPager){
  const sqlite3_io_methods *pMethods = pPager->fd->pMethods;
  return pMethods->iVersion>=2 && pMethods->xShmOpen!=0;
}

/*
** Open a connection to the write-ahead log file for pager pPager. If
** the log connection is already open, this function is a no-op.
**
** The caller must be holding a SHARED lock on the database file to call
** this function.











*/
SQLITE_PRIVATE int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen){



  int rc = SQLITE_OK;             /* Return code */

  assert( pPager->state>=PAGER_SHARED );


  if( !pPager->pWal ){
    if( !sqlite3PagerWalSupported(pPager) ) return SQLITE_CANTOPEN;

    /* Open the connection to the log file. If this operation fails, 
    ** (e.g. due to malloc() failure), unlock the database file and 
    ** return an error code.
    */
    rc = sqlite3WalOpen(pPager->pVfs, pPager->fd,
................................................................................
  ** it may need to be checkpointed before the connection can switch to
  ** rollback mode. Open it now so this can happen.
  */
  if( !pPager->pWal ){
    int logexists = 0;
    rc = sqlite3OsLock(pPager->fd, SQLITE_LOCK_SHARED);
    if( rc==SQLITE_OK ){
      rc = pagerHasWAL(pPager, &logexists);
    }
    if( rc==SQLITE_OK && logexists ){
      rc = sqlite3WalOpen(pPager->pVfs, pPager->fd,
                          pPager->zFilename, &pPager->pWal);
    }
  }
    
................................................................................
static int walIndexPage(Wal *pWal, int iPage, volatile u32 **ppPage){
  int rc = SQLITE_OK;

  /* Enlarge the pWal->apWiData[] array if required */
  if( pWal->nWiData<=iPage ){
    int nByte = sizeof(u32 *)*(iPage+1);
    volatile u32 **apNew;
    apNew = (volatile u32 **)sqlite3_realloc(pWal->apWiData, nByte);
    if( !apNew ){
      *ppPage = 0;
      return SQLITE_NOMEM;
    }
    memset(&apNew[pWal->nWiData], 0, sizeof(u32 *)*(iPage+1-pWal->nWiData));
    pWal->apWiData = apNew;
    pWal->nWiData = iPage+1;
  }

  /* Request a pointer to the required page from the VFS */
  if( pWal->apWiData[iPage]==0 ){
    rc = sqlite3OsShmMap(pWal->pDbFd, iPage, WALINDEX_PGSZ, 
................................................................................
static int walLockShared(Wal *pWal, int lockIdx){
  int rc;
  if( pWal->exclusiveMode ) return SQLITE_OK;
  rc = sqlite3OsShmLock(pWal->pDbFd, lockIdx, 1,
                        SQLITE_SHM_LOCK | SQLITE_SHM_SHARED);
  WALTRACE(("WAL%p: acquire SHARED-%s %s\n", pWal,
            walLockName(lockIdx), rc ? "failed" : "ok"));
  VVA_ONLY( pWal->lockError = (rc!=SQLITE_OK && rc!=SQLITE_BUSY); )
  return rc;
}
static void walUnlockShared(Wal *pWal, int lockIdx){
  if( pWal->exclusiveMode ) return;
  (void)sqlite3OsShmLock(pWal->pDbFd, lockIdx, 1,
                         SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED);
  WALTRACE(("WAL%p: release SHARED-%s\n", pWal, walLockName(lockIdx)));
................................................................................
static int walLockExclusive(Wal *pWal, int lockIdx, int n){
  int rc;
  if( pWal->exclusiveMode ) return SQLITE_OK;
  rc = sqlite3OsShmLock(pWal->pDbFd, lockIdx, n,
                        SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE);
  WALTRACE(("WAL%p: acquire EXCLUSIVE-%s cnt=%d %s\n", pWal,
            walLockName(lockIdx), n, rc ? "failed" : "ok"));
  VVA_ONLY( pWal->lockError = (rc!=SQLITE_OK && rc!=SQLITE_BUSY); )
  return rc;
}
static void walUnlockExclusive(Wal *pWal, int lockIdx, int n){
  if( pWal->exclusiveMode ) return;
  (void)sqlite3OsShmLock(pWal->pDbFd, lockIdx, n,
                         SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE);
  WALTRACE(("WAL%p: release EXCLUSIVE-%s cnt=%d\n", pWal,
................................................................................
**
** At most only the hash table containing pWal->hdr.mxFrame needs to be
** updated.  Any later hash tables will be automatically cleared when
** pWal->hdr.mxFrame advances to the point where those hash tables are
** actually needed.
*/
static void walCleanupHash(Wal *pWal){
  volatile ht_slot *aHash;        /* Pointer to hash table to clear */
  volatile u32 *aPgno;            /* Page number array for hash table */
  u32 iZero;                      /* frame == (aHash[x]+iZero) */
  int iLimit = 0;                 /* Zero values greater than this */
  int nByte;                      /* Number of bytes to zero in aPgno[] */
  int i;                          /* Used to iterate through aHash[] */

  assert( pWal->writeLock );
  testcase( pWal->hdr.mxFrame==HASHTABLE_NPAGE_ONE-1 );
  testcase( pWal->hdr.mxFrame==HASHTABLE_NPAGE_ONE );
................................................................................
      aHash[i] = 0;
    }
  }
  
  /* Zero the entries in the aPgno array that correspond to frames with
  ** frame numbers greater than pWal->hdr.mxFrame. 
  */
  nByte = ((char *)aHash - (char *)&aPgno[iLimit+1]);
  memset((void *)&aPgno[iLimit+1], 0, nByte);

#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
  /* Verify that the every entry in the mapping region is still reachable
  ** via the hash table even after the cleanup.
  */
  if( iLimit ){
................................................................................

/*
** Set an entry in the wal-index that will map database page number
** pPage into WAL frame iFrame.
*/
static int walIndexAppend(Wal *pWal, u32 iFrame, u32 iPage){
  int rc;                         /* Return code */
  u32 iZero;                      /* One less than frame number of aPgno[1] */
  volatile u32 *aPgno;            /* Page number array */
  volatile ht_slot *aHash;        /* Hash table */

  rc = walHashGet(pWal, walFramePage(iFrame), &aHash, &aPgno, &iZero);

  /* Assuming the wal-index file was successfully mapped, populate the
  ** page number array and hash table entry.
  */
  if( rc==SQLITE_OK ){
................................................................................
    idx = iFrame - iZero;
    assert( idx <= HASHTABLE_NSLOT/2 + 1 );
    
    /* If this is the first entry to be added to this hash-table, zero the
    ** entire hash table and aPgno[] array before proceding. 
    */
    if( idx==1 ){
      int nByte = (u8 *)&aHash[HASHTABLE_NSLOT] - (u8 *)&aPgno[1];
      memset((void*)&aPgno[1], 0, nByte);
    }

    /* If the entry in aPgno[] is already set, then the previous writer
    ** must have exited unexpectedly in the middle of a transaction (after
    ** writing one or more dirty pages to the WAL to free up memory). 
    ** Remove the remnants of that writers uncommitted transaction from 
................................................................................
    }

    /* Write the aPgno[] array entry and the hash-table slot. */
    for(iKey=walHash(iPage); aHash[iKey]; iKey=walNextHash(iKey)){
      assert( nCollide++ < idx );
    }
    aPgno[idx] = iPage;
    aHash[iKey] = idx;

#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
    /* Verify that the number of entries in the hash table exactly equals
    ** the number of entries in the mapping region.
    */
    {
      int i;           /* Loop counter */
................................................................................
    if( (magic&0xFFFFFFFE)!=WAL_MAGIC 
     || szPage&(szPage-1) 
     || szPage>SQLITE_MAX_PAGE_SIZE 
     || szPage<512 
    ){
      goto finished;
    }
    pWal->hdr.bigEndCksum = (magic&0x00000001);
    pWal->szPage = szPage;
    pWal->nCkpt = sqlite3Get4byte(&aBuf[12]);
    memcpy(&pWal->hdr.aSalt, &aBuf[16], 8);

    /* Verify that the WAL header checksum is correct */
    walChecksumBytes(pWal->hdr.bigEndCksum==SQLITE_BIGENDIAN, 
        aBuf, WAL_HDRSIZE-2*4, 0, pWal->hdr.aFrameCksum
    );
................................................................................
      rc = walIndexAppend(pWal, ++iFrame, pgno);
      if( rc!=SQLITE_OK ) break;

      /* If nTruncate is non-zero, this is a commit record. */
      if( nTruncate ){
        pWal->hdr.mxFrame = iFrame;
        pWal->hdr.nPage = nTruncate;
        pWal->hdr.szPage = szPage;
        aFrameCksum[0] = pWal->hdr.aFrameCksum[0];
        aFrameCksum[1] = pWal->hdr.aFrameCksum[1];
      }
    }

    sqlite3_free(aFrame);
  }
................................................................................
){
  struct Sublist {
    int nList;                    /* Number of elements in aList */
    ht_slot *aList;               /* Pointer to sub-list content */
  };

  const int nList = *pnList;      /* Size of input list */
  int nMerge;                     /* Number of elements in list aMerge */
  ht_slot *aMerge;                /* List to be merged */
  int iList;                      /* Index into input list */
  int iSub = 0;                   /* Index into aSub array */
  struct Sublist aSub[13];        /* Array of sub-lists */

  memset(aSub, 0, sizeof(aSub));
  assert( nList<=HASHTABLE_NPAGE && nList>0 );
  assert( HASHTABLE_NPAGE==(1<<(ArraySize(aSub)-1)) );
................................................................................
    rc = walHashGet(pWal, i, &aHash, &aPgno, &iZero);
    if( rc==SQLITE_OK ){
      int j;                      /* Counter variable */
      int nEntry;                 /* Number of entries in this segment */
      ht_slot *aIndex;            /* Sorted index for this segment */

      aPgno++;
      nEntry = ((i+1)==nSegment)?iLast-iZero:(u32 *)aHash-(u32 *)aPgno;
      aIndex = &((ht_slot *)&p->aSegment[p->nSegment])[iZero];
      iZero++;
  
      for(j=0; j<nEntry; j++){
        aIndex[j] = j;
      }
      walMergesort((u32 *)aPgno, aTmp, aIndex, &nEntry);
      p->aSegment[i].iZero = iZero;
      p->aSegment[i].nEntry = nEntry;
      p->aSegment[i].aIndex = aIndex;
      p->aSegment[i].aPgno = (u32 *)aPgno;
    }
................................................................................

    walIndexClose(pWal, isDelete);
    sqlite3OsClose(pWal->pWalFd);
    if( isDelete ){
      sqlite3OsDelete(pWal->pVfs, pWal->zWalName, 0);
    }
    WALTRACE(("WAL%p: closed\n", pWal));
    sqlite3_free(pWal->apWiData);
    sqlite3_free(pWal);
  }
  return rc;
}

/*
** Try to read the wal-index header.  Return 0 on success and 1 if
................................................................................
** If and only if the read is consistent and the header is different from
** pWal->hdr, then pWal->hdr is updated to the content of the new header
** and *pChanged is set to 1.
**
** If the checksum cannot be verified return non-zero. If the header
** is read successfully and the checksum verified, return zero.
*/
int walIndexTryHdr(Wal *pWal, int *pChanged){
  u32 aCksum[2];                  /* Checksum on the header content */
  WalIndexHdr h1, h2;             /* Two copies of the header content */
  WalIndexHdr volatile *aHdr;     /* Header in shared memory */

  /* The first page of the wal-index must be mapped at this point. */
  assert( pWal->nWiData>0 && pWal->apWiData[0] );

................................................................................
    if( pInfo->aReadMark[mxI]!=mxReadMark
     || memcmp((void *)walIndexHdr(pWal), &pWal->hdr, sizeof(WalIndexHdr))
    ){
      walUnlockShared(pWal, WAL_READ_LOCK(mxI));
      return WAL_RETRY;
    }else{
      assert( mxReadMark<=pWal->hdr.mxFrame );
      pWal->readLock = mxI;
    }
  }
  return rc;
}

/*
** Begin a read transaction on the database.
................................................................................
    sqlite3Put4byte(&aWalHdr[8], szPage);
    sqlite3Put4byte(&aWalHdr[12], pWal->nCkpt);
    memcpy(&aWalHdr[16], pWal->hdr.aSalt, 8);
    walChecksumBytes(1, aWalHdr, WAL_HDRSIZE-2*4, 0, aCksum);
    sqlite3Put4byte(&aWalHdr[24], aCksum[0]);
    sqlite3Put4byte(&aWalHdr[28], aCksum[1]);
    
    pWal->szPage = szPage;
    pWal->hdr.bigEndCksum = SQLITE_BIGENDIAN;
    pWal->hdr.aFrameCksum[0] = aCksum[0];
    pWal->hdr.aFrameCksum[1] = aCksum[1];

    rc = sqlite3OsWrite(pWal->pWalFd, aWalHdr, sizeof(aWalHdr), 0);
    WALTRACE(("WAL%p: wal-header write %s\n", pWal, rc ? "failed" : "ok"));
    if( rc!=SQLITE_OK ){
................................................................................
    iFrame++;
    nLast--;
    rc = walIndexAppend(pWal, iFrame, pLast->pgno);
  }

  if( rc==SQLITE_OK ){
    /* Update the private copy of the header. */
    pWal->hdr.szPage = szPage;
    pWal->hdr.mxFrame = iFrame;
    if( isCommit ){
      pWal->hdr.iChange++;
      pWal->hdr.nPage = nTruncate;
    }
    /* If this is a commit, update the wal-index header too. */
    if( isCommit ){
................................................................................
  BtShared *pBt,          /* The database file */
  Pgno pgno,           /* Number of the page to get */
  MemPage **ppPage     /* Write the page pointer here */
){
  int rc;
  assert( sqlite3_mutex_held(pBt->mutex) );

  if( pgno<=0 || pgno>btreePagecount(pBt) ){
    return SQLITE_CORRUPT_BKPT;
  }
  rc = btreeGetPage(pBt, pgno, ppPage, 0);
  if( rc==SQLITE_OK ){
    rc = btreeInitPage(*ppPage);
    if( rc!=SQLITE_OK ){
      releasePage(*ppPage);
    }
  }




  return rc;
}

/*
** Release a MemPage.  This should be called once for each prior
** call to btreeGetPage.
*/
................................................................................

  /* Any read-only or read-write transaction implies a read-lock on 
  ** page 1. So if some other shared-cache client already has a write-lock 
  ** on page 1, the transaction cannot be opened. */
  rc = querySharedCacheTableLock(p, MASTER_ROOT, READ_LOCK);
  if( SQLITE_OK!=rc ) goto trans_begun;

  pBt->initiallyEmpty = pBt->nPage==0;
  do {
    /* Call lockBtree() until either pBt->pPage1 is populated or
    ** lockBtree() returns something other than SQLITE_OK. lockBtree()
    ** may return SQLITE_OK but leave pBt->pPage1 set to 0 if after
    ** reading page 1 it discovers that the page-size of the database 
    ** file is not pBt->pageSize. In this case lockBtree() will update
    ** pBt->pageSize to the page-size of the file on disk.
................................................................................
  assert( cursorHoldsMutex(pCur) );
  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
  rc = moveToRoot(pCur);
  if( rc==SQLITE_OK ){
    if( pCur->eState==CURSOR_INVALID ){
      assert( pCur->apPage[pCur->iPage]->nCell==0 );
      *pRes = 1;
      rc = SQLITE_OK;
    }else{
      assert( pCur->apPage[pCur->iPage]->nCell>0 );
      *pRes = 0;
      rc = moveToLeftmost(pCur);
    }
  }
  return rc;
................................................................................
 
  assert( pBtree->inTrans==TRANS_NONE );
  assert( iVersion==1 || iVersion==2 );

  /* If setting the version fields to 1, do not automatically open the
  ** WAL connection, even if the version fields are currently set to 2.
  */
  pBt->doNotUseWAL = (iVersion==1);

  rc = sqlite3BtreeBeginTrans(pBtree, 0);
  if( rc==SQLITE_OK ){
    u8 *aData = pBt->pPage1->aData;
    if( aData[18]!=(u8)iVersion || aData[19]!=(u8)iVersion ){
      rc = sqlite3BtreeBeginTrans(pBtree, 2);
      if( rc==SQLITE_OK ){
................................................................................
    if( bCloseTrans ){
      TESTONLY( int rc2 );
      TESTONLY( rc2  = ) sqlite3BtreeCommitPhaseOne(p->pSrc, 0);
      TESTONLY( rc2 |= ) sqlite3BtreeCommitPhaseTwo(p->pSrc);
      assert( rc2==SQLITE_OK );
    }
  



    p->rc = rc;
  }
  if( p->pDestDb ){
    sqlite3_mutex_leave(p->pDestDb->mutex);
  }
  sqlite3BtreeLeave(p->pSrc);
  sqlite3_mutex_leave(p->pSrcDb->mutex);
................................................................................
** an OP_Trace instruction is always inserted by sqlite3VdbeGet() as soon as
** a new VDBE is created.  So we are free to set addr to p->nOp-1 without
** having to double-check to make sure that the result is non-negative. But
** if SQLITE_OMIT_TRACE is defined, the OP_Trace is omitted and we do need to
** check the value of p->nOp-1 before continuing.
*/
SQLITE_PRIVATE VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){


  static const VdbeOp dummy;
  assert( p->magic==VDBE_MAGIC_INIT );
  if( addr<0 ){
#ifdef SQLITE_OMIT_TRACE
    if( p->nOp==0 ) return (VdbeOp*)&dummy;
#endif
    addr = p->nOp - 1;
  }
................................................................................
  BtCursor *pCrsr;
  int res;
#endif /* local variables moved into u.bl */

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  u.bl.pC = p->apCsr[pOp->p1];
  assert( u.bl.pC!=0 );

  if( (u.bl.pCrsr = u.bl.pC->pCursor)!=0 ){
    rc = sqlite3BtreeFirst(u.bl.pCrsr, &u.bl.res);
    u.bl.pC->atFirst = u.bl.res==0 ?1:0;
    u.bl.pC->deferredMoveto = 0;
    u.bl.pC->cacheStatus = CACHE_STALE;
    u.bl.pC->rowidIsValid = 0;
  }else{
    u.bl.res = 1;
  }
  u.bl.pC->nullRow = (u8)u.bl.res;
  assert( pOp->p2>0 && pOp->p2<p->nOp );
  if( u.bl.res ){
    pc = pOp->p2 - 1;
  }
  break;
................................................................................
*/
case OP_Checkpoint: {
  rc = sqlite3Checkpoint(db, pOp->p1);
  break;
};  
#endif


/* Opcode: JournalMode P1 P2 P3 * P5
**
** Change the journal mode of database P1 to P3. P3 must be one of the
** PAGER_JOURNALMODE_XXX values. If changing between the various rollback
** modes (delete, truncate, persist, off and memory), this is a simple
** operation. No IO is required.
**
................................................................................
  pOut->flags = MEM_Str|MEM_Static|MEM_Term;
  pOut->z = (char *)sqlite3JournalModename(u.cd.eNew);
  pOut->n = sqlite3Strlen30(pOut->z);
  pOut->enc = SQLITE_UTF8;
  sqlite3VdbeChangeEncoding(pOut, encoding);
  break;
};  


#if !defined(SQLITE_OMIT_VACUUM) && !defined(SQLITE_OMIT_ATTACH)
/* Opcode: Vacuum * * * * *
**
** Vacuum the entire database.  This opcode will cause other virtual
** machines to be created and run.  It may not be called from within
** a transaction.
................................................................................
  jrnlSync,      /* xSync */
  jrnlFileSize,  /* xFileSize */
  0,             /* xLock */
  0,             /* xUnlock */
  0,             /* xCheckReservedLock */
  0,             /* xFileControl */
  0,             /* xSectorSize */
  0              /* xDeviceCharacteristics */





};

/* 
** Open a journal file.
*/
SQLITE_PRIVATE int sqlite3JournalOpen(
  sqlite3_vfs *pVfs,         /* The VFS to use for actual file I/O */
................................................................................
  memjrnlSync,      /* xSync */
  memjrnlFileSize,  /* xFileSize */
  0,                /* xLock */
  0,                /* xUnlock */
  0,                /* xCheckReservedLock */
  0,                /* xFileControl */
  0,                /* xSectorSize */
  0                 /* xDeviceCharacteristics */





};

/* 
** Open a journal file.
*/
SQLITE_PRIVATE void sqlite3MemJournalOpen(sqlite3_file *pJfd){
  MemJournal *p = (MemJournal *)pJfd;
................................................................................
    if( zDb ){
      sqlite3ErrorMsg(pParse, "%s: %s.%s.%s", zErr, zDb, zTab, zCol);
    }else if( zTab ){
      sqlite3ErrorMsg(pParse, "%s: %s.%s", zErr, zTab, zCol);
    }else{
      sqlite3ErrorMsg(pParse, "%s: %s", zErr, zCol);
    }

    pTopNC->nErr++;
  }

  /* If a column from a table in pSrcList is referenced, then record
  ** this fact in the pSrcList.a[].colUsed bitmask.  Column 0 causes
  ** bit 0 to be set.  Column 1 sets bit 1.  And so forth.  If the
  ** column number is greater than the number of bits in the bitmask
................................................................................

    for(j=0, pTabCol=pTab->aCol; j<pTab->nCol; j++, pTabCol++){
      if( sqlite3StrICmp(zColName, pTabCol->zName)==0 ) break;
    }
    if( j>=pTab->nCol ){
      sqlite3ErrorMsg(pParse, "table %s has no column named %s",
        pTab->zName, zColName);

      goto exit_create_index;
    }
    pIndex->aiColumn[i] = j;
    /* Justification of the ALWAYS(pListItem->pExpr->pColl):  Because of
    ** the way the "idxlist" non-terminal is constructed by the parser,
    ** if pListItem->pExpr is not null then either pListItem->pExpr->pColl
    ** must exist or else there must have been an OOM error.  But if there
................................................................................
      }
      if( j>=pTab->nCol ){
        if( sqlite3IsRowid(pColumn->a[i].zName) ){
          keyColumn = i;
        }else{
          sqlite3ErrorMsg(pParse, "table %S has no column named %s",
              pTabList, 0, pColumn->a[i].zName);
          pParse->nErr++;
          goto insert_cleanup;
        }
      }
    }
  }

  /* If there is no IDLIST term but the table has an integer primary
................................................................................
    Index *pIdx;
    for(pIdx=pTab->pIndex; 
        pIdx && sqlite3StrICmp(pIdx->zName, zIndex); 
        pIdx=pIdx->pNext
    );
    if( !pIdx ){
      sqlite3ErrorMsg(pParse, "no such index: %s", zIndex, 0);

      return SQLITE_ERROR;
    }
    pFrom->pIndex = pIdx;
  }
  return SQLITE_OK;
}

................................................................................
    pTrigger = sqlite3HashFind(&(db->aDb[j].pSchema->trigHash), zName, nName);
    if( pTrigger ) break;
  }
  if( !pTrigger ){
    if( !noErr ){
      sqlite3ErrorMsg(pParse, "no such trigger: %S", pName, 0);
    }

    goto drop_trigger_cleanup;
  }
  sqlite3DropTriggerPtr(pParse, pTrigger);

drop_trigger_cleanup:
  sqlite3SrcListDelete(db, pName);
}
................................................................................
    }
    if( j>=pTab->nCol ){
      if( sqlite3IsRowid(pChanges->a[i].zName) ){
        chngRowid = 1;
        pRowidExpr = pChanges->a[i].pExpr;
      }else{
        sqlite3ErrorMsg(pParse, "no such column: %s", pChanges->a[i].zName);

        goto update_cleanup;
      }
    }
#ifndef SQLITE_OMIT_AUTHORIZATION
    {
      int rc;
      rc = sqlite3AuthCheck(pParse, SQLITE_UPDATE, pTab->zName,
................................................................................
        pIdx->aiColumn[n] = pTerm->u.leftColumn;
        pColl = sqlite3BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
        pIdx->azColl[n] = pColl->zName;
        n++;
      }
    }
  }
  assert( n==pLevel->plan.nEq );

  /* Add additional columns needed to make the automatic index into
  ** a covering index */
  for(i=0; i<mxBitCol; i++){
    if( extraCols & (((Bitmask)1)<<i) ){
      pIdx->aiColumn[n] = i;
      pIdx->azColl[n] = "BINARY";
................................................................................
    zEndAff = sqlite3DbStrDup(pParse->db, zStartAff);
    addrNxt = pLevel->addrNxt;

    /* If we are doing a reverse order scan on an ascending index, or
    ** a forward order scan on a descending index, interchange the 
    ** start and end terms (pRangeStart and pRangeEnd).
    */
    if( bRev==(pIdx->aSortOrder[nEq]==SQLITE_SO_ASC) ){
      SWAP(WhereTerm *, pRangeEnd, pRangeStart);
    }

    testcase( pRangeStart && pRangeStart->eOperator & WO_LE );
    testcase( pRangeStart && pRangeStart->eOperator & WO_GE );
    testcase( pRangeEnd && pRangeEnd->eOperator & WO_LE );
    testcase( pRangeEnd && pRangeEnd->eOperator & WO_GE );
................................................................................
  return rc;
}

/*
** An sqlite3_exec() callback for fts3TableExists.
*/
static int fts3TableExistsCallback(void *pArg, int n, char **pp1, char **pp2){



  *(int*)pArg = 1;
  return 1;
}

/*
** Determine if a table currently exists in the database.
*/
................................................................................
  if( *pRc ) return;
  zSql = sqlite3_mprintf(
    "SELECT 1 FROM %Q.sqlite_master WHERE name='%q%s'",
    zDb, zName, zSuffix
  );    
  rc = sqlite3_exec(db, zSql, fts3TableExistsCallback, &res, 0);
  sqlite3_free(zSql);
  *pResult = res & 0xff;
  if( rc!=SQLITE_ABORT ) *pRc = rc;
}

/*
** This function is the implementation of both the xConnect and xCreate
** methods of the FTS3 virtual table.
**

**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.7.0"
#define SQLITE_VERSION_NUMBER 3007000
#define SQLITE_SOURCE_ID      "2010-07-03 13:59:01 3b20ad03be55613d922d81aec5313327bf4098b9"

/*
** CAPI3REF: Run-Time Library Version Numbers
** KEYWORDS: sqlite3_version, sqlite3_sourceid
**
** These interfaces provide the same information as the [SQLITE_VERSION],
** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
................................................................................
**     sqlite3OsOpen()
**     sqlite3OsRead()
**     sqlite3OsWrite()
**     sqlite3OsSync()
**     sqlite3OsLock()
**
*/
#if defined(SQLITE_TEST)
SQLITE_API int sqlite3_memdebug_vfs_oom_test = 1;
  #define DO_OS_MALLOC_TEST(x)                                       \
  if (sqlite3_memdebug_vfs_oom_test && (!x || !sqlite3IsMemJournal(x))) {  \
    void *pTstAlloc = sqlite3Malloc(10);                             \
    if (!pTstAlloc) return SQLITE_IOERR_NOMEM;                       \
    sqlite3_free(pTstAlloc);                                         \
  }
#else
  #define DO_OS_MALLOC_TEST(x)
#endif
................................................................................
/*
** Stub routines for all mutex methods.
**
** This routines provide no mutual exclusion or error checking.
*/
static int noopMutexInit(void){ return SQLITE_OK; }
static int noopMutexEnd(void){ return SQLITE_OK; }
static sqlite3_mutex *noopMutexAlloc(int id){ 
  UNUSED_PARAMETER(id);
  return (sqlite3_mutex*)8; 
}
static void noopMutexFree(sqlite3_mutex *p){ UNUSED_PARAMETER(p); return; }
static void noopMutexEnter(sqlite3_mutex *p){ UNUSED_PARAMETER(p); return; }
static int noopMutexTry(sqlite3_mutex *p){
  UNUSED_PARAMETER(p);
  return SQLITE_OK;
}
static void noopMutexLeave(sqlite3_mutex *p){ UNUSED_PARAMETER(p); return; }

SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3NoopMutex(void){
  static const sqlite3_mutex_methods sMutex = {
    noopMutexInit,
    noopMutexEnd,
    noopMutexAlloc,
    noopMutexFree,
................................................................................

/*
** If compiled with SQLITE_MUTEX_NOOP, then the no-op mutex implementation
** is used regardless of the run-time threadsafety setting.
*/
#ifdef SQLITE_MUTEX_NOOP
SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3DefaultMutex(void){
  return sqlite3NoopMutex();
}
#endif /* SQLITE_MUTEX_NOOP */
#endif /* SQLITE_MUTEX_OMIT */

/************** End of mutex_noop.c ******************************************/
/************** Begin file mutex_os2.c ***************************************/
/*
................................................................................
**
** All loads and stores begun before the barrier must complete before
** any load or store begun after the barrier.
*/
static void unixShmBarrier(
  sqlite3_file *fd                /* Database file holding the shared memory */
){
  UNUSED_PARAMETER(fd);
  unixEnterMutex();
  unixLeaveMutex();
}

/*
** This function is called to obtain a pointer to region iRegion of the 
** shared-memory associated with the database file fd. Shared-memory regions 
................................................................................
/*
** Find the current time (in Universal Coordinated Time).  Write the
** current time and date as a Julian Day number into *prNow and
** return 0.  Return 1 if the time and date cannot be found.
*/
static int unixCurrentTime(sqlite3_vfs *NotUsed, double *prNow){
  sqlite3_int64 i;
  UNUSED_PARAMETER(NotUsed);
  unixCurrentTimeInt64(0, &i);
  *prNow = i/86400000.0;
  return 0;
}

/*
** We added the xGetLastError() method with the intention of providing
................................................................................

  if( lPath[len-1]!='/' ){
    len = strlcat(lPath, "/", maxLen);
  }
  
  /* transform the db path to a unique cache name */
  dbLen = (int)strlen(dbPath);
  for( i=0; i<dbLen && (i+len+7)<(int)maxLen; i++){
    char c = dbPath[i];
    lPath[i+len] = (c=='/')?'_':c;
  }
  lPath[i+len]='\0';
  strlcat(lPath, ":auto:", maxLen);
  OSTRACE(("GETLOCKPATH  proxy lock path=%s pid=%d\n", lPath, getpid()));
  return SQLITE_OK;
................................................................................
#ifdef SQLITE_TEST
/* simulate multiple hosts by creating unique hostid file paths */
SQLITE_API int sqlite3_hostid_num = 0;
#endif

#define PROXY_HOSTIDLEN    16  /* conch file host id length */

/* Not always defined in the headers as it ought to be */
extern int gethostuuid(uuid_t id, const struct timespec *wait);

/* get the host ID via gethostuuid(), pHostID must point to PROXY_HOSTIDLEN 
** bytes of writable memory.
*/
static int proxyGetHostID(unsigned char *pHostID, int *pError){
  struct timespec timeout = {1, 0}; /* 1 sec timeout */
  
  assert(PROXY_HOSTIDLEN == sizeof(uuid_t));
................................................................................
  char buf[PROXY_MAXCONCHLEN];
  char *cPath = pCtx->conchFilePath;
  size_t readLen = 0;
  size_t pathLen = 0;
  char errmsg[64] = "";
  int fd = -1;
  int rc = -1;
  UNUSED_PARAMETER(myHostID);

  /* create a new path by replace the trailing '-conch' with '-break' */
  pathLen = strlcpy(tPath, cPath, MAXPATHLEN);
  if( pathLen>MAXPATHLEN || pathLen<6 || 
     (strlcpy(&tPath[pathLen-5], "break", 6) != 5) ){
    sprintf(errmsg, "path error (len %d)", (int)pathLen);
    goto end_breaklock;
................................................................................
  }
  /* write it out to the temporary break file */
  fd = open(tPath, (O_RDWR|O_CREAT|O_EXCL), SQLITE_DEFAULT_FILE_PERMISSIONS);
  if( fd<0 ){
    sprintf(errmsg, "create failed (%d)", errno);
    goto end_breaklock;
  }
  if( pwrite(fd, buf, readLen, 0) != (ssize_t)readLen ){
    sprintf(errmsg, "write failed (%d)", errno);
    goto end_breaklock;
  }
  if( rename(tPath, cPath) ){
    sprintf(errmsg, "rename failed (%d)", errno);
    goto end_breaklock;
  }
................................................................................
    }

    /* Check to see if another process is holding the dead-man switch.
    ** If not, truncate the file to zero length. 
    */
    if( winShmSystemLock(pShmNode, _SHM_WRLCK, WIN_SHM_DMS, 1)==SQLITE_OK ){
      rc = winTruncate((sqlite3_file *)&pShmNode->hFile, 0);
      if( rc!=SQLITE_OK ){
        rc = SQLITE_IOERR_SHMOPEN;
      }
    }
    if( rc==SQLITE_OK ){
      winShmSystemLock(pShmNode, _SHM_UNLCK, WIN_SHM_DMS, 1);
      rc = winShmSystemLock(pShmNode, _SHM_RDLCK, WIN_SHM_DMS, 1);
    }
    if( rc ) goto shm_open_err;
  }
................................................................................
**
** All loads and stores begun before the barrier must complete before
** any load or store begun after the barrier.
*/
static void winShmBarrier(
  sqlite3_file *fd          /* Database holding the shared memory */
){
  UNUSED_PARAMETER(fd);
  /* MemoryBarrier(); // does not work -- do not know why not */
  winShmEnterMutex();
  winShmLeaveMutex();
}

#else
# define winShmOpen    0
................................................................................
# define sqlite3WalOpen(x,y,z)                 0
# define sqlite3WalClose(w,x,y,z)              0
# define sqlite3WalBeginReadTransaction(y,z)   0
# define sqlite3WalEndReadTransaction(z)
# define sqlite3WalRead(v,w,x,y,z)             0
# define sqlite3WalDbsize(y,z)
# define sqlite3WalBeginWriteTransaction(y)    0
# define sqlite3WalEndWriteTransaction(x)      0
# define sqlite3WalUndo(x,y,z)                 0
# define sqlite3WalSavepoint(y,z)
# define sqlite3WalSavepointUndo(y,z)          0
# define sqlite3WalFrames(u,v,w,x,y,z)         0
# define sqlite3WalCheckpoint(u,v,w,x)         0
# define sqlite3WalCallback(z)                 0
# define sqlite3WalExclusiveMode(y,z)          0
#else

#define WAL_SAVEPOINT_NDATA 4

/* Connection to a write-ahead log (WAL) file. 
** There is one object of this type for each pager. 
*/
................................................................................
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 */
#ifndef SQLITE_OMIT_WAL
  u32 aWalData[WAL_SAVEPOINT_NDATA];        /* WAL savepoint context */
#endif
};

/*
** A open page cache is an instance of the following structure.
**
** errCode
**
................................................................................
  }
  pPager->state = PAGER_SHARED;

  return rc;
}

/*
** Check for the existence of or delete the *-wal file that corresponds to
** the database opened by pPager.
**
** When pExists!=NULL, set *pExists to 1 if the *-wal file exists, or 0
** if the *-wal file does not exist.
**
** When pExists==NULL, delete the *-wal file if it exists, or the do
** nothing if the *-wal file does not exist.
**
** Return SQLITE_OK on success. If on an IO or OOM error occurs, return
** an SQLite error code.
*/
static int pagerCheckForOrDeleteWAL(Pager *pPager, int *pExists){
  int rc;                         /* Return code */
  char *zWal;                     /* Name of the WAL file */

  assert( !pPager->tempFile );
  zWal = sqlite3_mprintf("%s-wal", pPager->zFilename);
  if( !zWal ){
    rc = SQLITE_NOMEM;
  }else{
    if( pExists ){
      rc = sqlite3OsAccess(pPager->pVfs, zWal, SQLITE_ACCESS_EXISTS, pExists);
    }else{
      rc = sqlite3OsDelete(pPager->pVfs, zWal, 0);
    }
    sqlite3_free(zWal);
  }
  return rc;
}

/*
** Check if the *-wal file that corresponds to the database opened by pPager
** exists if the database is not empy, or verify that the *-wal file does
** not exist (by deleting it) if the database file is empty.
**
** If the database is not empty and the *-wal file exists, open the pager
** in WAL mode.  If the database is empty or if no *-wal file exists and
** if no error occurs, make sure Pager.journalMode is not set to

** PAGER_JOURNALMODE_WAL.
**
** Return SQLITE_OK or an error code.
**
** If the WAL file is opened, also open a snapshot (read transaction).
**
** The caller must hold a SHARED lock on the database file to call this
** function. Because an EXCLUSIVE lock on the db file is required to delete 
** a WAL on a none-empty database, this ensures there is no race condition 
** between the xAccess() below and an xDelete() being executed by some 
** other connection.
*/
static int pagerOpenWalIfPresent(Pager *pPager){
  int rc = SQLITE_OK;
  if( !pPager->tempFile ){
    int isWal;                    /* True if WAL file exists */
    int nPage;                    /* Size of the database file */
    assert( pPager->state>=SHARED_LOCK );
    rc = sqlite3PagerPagecount(pPager, &nPage);
    if( rc ) return rc;
    if( nPage==0 ){
      rc = pagerCheckForOrDeleteWAL(pPager, 0);
      isWal = 0;
    }else{
      rc = pagerCheckForOrDeleteWAL(pPager, &isWal);
    }
    if( rc==SQLITE_OK ){
      if( isWal ){
        pager_reset(pPager);
        rc = sqlite3PagerOpenWal(pPager, 0);
        if( rc==SQLITE_OK ){
          rc = pagerBeginReadTransaction(pPager);
        }
................................................................................
SQLITE_PRIVATE int sqlite3PagerMaxPageCount(Pager *pPager, int mxPage){
  int nPage;
  if( mxPage>0 ){
    pPager->mxPgno = mxPage;
  }
  if( pPager->state!=PAGER_UNLOCK ){
    sqlite3PagerPagecount(pPager, &nPage);
    assert( (int)pPager->mxPgno>=nPage );
  }
  return pPager->mxPgno;
}

/*
** The following set of routines are used to disable the simulated
** I/O error mechanism.  These routines are used to avoid simulated
................................................................................
      ** other bytes change randomly with each file change when
      ** a codec is in use.
      ** 
      ** There is a vanishingly small chance that a change will not be 
      ** detected.  The chance of an undetected change is so small that
      ** it can be neglected.
      */
      int nPage = 0;
      char dbFileVers[sizeof(pPager->dbFileVers)];
      sqlite3PagerPagecount(pPager, &nPage);

      if( pPager->errCode ){
        rc = pPager->errCode;
        goto failed;
      }
................................................................................
    }

    /* No need to open the journal file at this time.  It will be
    ** opened before it is written to.  If we defer opening the journal,
    ** we might save the work of creating a file if the transaction
    ** ends up being a no-op.
    */















    if( rc!=SQLITE_OK ){
      assert( !pPager->dbModified );
      /* Ignore any IO error that occurs within pager_end_transaction(). The
      ** purpose of this call is to reset the internal state of the pager
      ** sub-system. It doesn't matter if the journal-file is not properly
      ** finalized at this point (since it is not a valid journal file anyway).
      */
      pager_end_transaction(pPager, 0);
    }
  }

  PAGERTRACE(("TRANSACTION %d\n", PAGERID(pPager)));
  return rc;
}

/*
** Mark a single data page as writeable. The page is written into the 
** main journal or sub-journal as required. If the page is written into
** one of the journals, the corresponding bit is set in the 
................................................................................
    ** written to the transaction journal or the ckeckpoint journal
    ** or both.
    **
    ** Higher level routines should have already started a transaction,
    ** which means they have acquired the necessary locks but the rollback
    ** journal might not yet be open.
    */
    assert( pPager->state>=RESERVED_LOCK );



    if( pPager->pInJournal==0
     && pPager->journalMode!=PAGER_JOURNALMODE_OFF 
     && !pagerUseWal(pPager)
    ){
      assert( pPager->useJournal );
      rc = pager_open_journal(pPager);
      if( rc!=SQLITE_OK ) return rc;
................................................................................
      ** Otherwise, if the optimization is both enabled and applicable,
      ** then call pager_incr_changecounter() to update the change-counter
      ** in 'direct' mode. In this case the journal file will never be
      ** created for this transaction.
      */
  #ifdef SQLITE_ENABLE_ATOMIC_WRITE
      PgHdr *pPg;
      assert( isOpen(pPager->jfd) 
           || pPager->journalMode==PAGER_JOURNALMODE_OFF 
           || pPager->journalMode==PAGER_JOURNALMODE_WAL 
      );
      if( !zMaster && isOpen(pPager->jfd) 
       && pPager->journalOff==jrnlBufferSize(pPager) 
       && pPager->dbSize>=pPager->dbFileSize
       && (0==(pPg = sqlite3PcacheDirtyList(pPager->pPCache)) || 0==pPg->pDirty)
      ){
        /* Update the db file change counter via the direct-write method. The 
        ** following call will modify the in-memory representation of page 1 
................................................................................
  if( NEVER(pPager->errCode) ) return pPager->errCode;

  /* This function should not be called if the pager is not in at least
  ** PAGER_RESERVED state. **FIXME**: Make it so that this test always
  ** fails - make it so that we never reach this point if we do not hold
  ** all necessary locks.
  */
  if( NEVER(pPager->state<PAGER_RESERVED) ) return SQLITE_ERROR;

  /* An optimization. If the database was not actually modified during
  ** this transaction, the pager is running in exclusive-mode and is
  ** using persistent journals, then this function is a no-op.
  **
  ** The start of the journal file currently contains a single journal 
  ** header with the nRec field set to 0. If such a journal is used as
................................................................................
  ** to the database file. So there is no need to zero the journal 
  ** header. Since the pager is in exclusive mode, there is no need
  ** to drop any locks either.
  */
  if( pPager->dbModified==0 && pPager->exclusiveMode 
   && pPager->journalMode==PAGER_JOURNALMODE_PERSIST
  ){
    assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) || !pPager->journalOff );
    return SQLITE_OK;
  }

  PAGERTRACE(("COMMIT %d\n", PAGERID(pPager)));
  assert( pPager->state==PAGER_SYNCED || MEMDB || !pPager->dbModified );
  rc = pager_end_transaction(pPager, pPager->setMaster);
  return pager_error(pPager, rc);
................................................................................
  return pPager->noSync;
}

#ifdef SQLITE_HAS_CODEC
/*
** Set or retrieve the codec for this pager
*/
SQLITE_PRIVATE void sqlite3PagerSetCodec(
  Pager *pPager,
  void *(*xCodec)(void*,void*,Pgno,int),
  void (*xCodecSizeChng)(void*,int,int),
  void (*xCodecFree)(void*),
  void *pCodec
){
  if( pPager->xCodecFree ) pPager->xCodecFree(pPager->pCodec);
  pPager->xCodec = pPager->memDb ? 0 : xCodec;
  pPager->xCodecSizeChng = xCodecSizeChng;
  pPager->xCodecFree = xCodecFree;
  pPager->pCodec = pCodec;
  pagerReportSize(pPager);
}
SQLITE_PRIVATE void *sqlite3PagerGetCodec(Pager *pPager){
  return pPager->pCodec;
}
#endif

#ifndef SQLITE_OMIT_AUTOVACUUM
/*
** Move the page pPg to location pgno in the file.
................................................................................
/*
** Return TRUE if the pager is in a state where it is OK to change the
** journalmode.  Journalmode changes can only happen when the database
** is unmodified.
*/
SQLITE_PRIVATE int sqlite3PagerOkToChangeJournalMode(Pager *pPager){
  if( pPager->dbModified ) return 0;
  if( NEVER(isOpen(pPager->jfd) && pPager->journalOff>0) ) return 0;
  return 1;
}

/*
** Get/set the size-limit used for persistent journal files.
**
** Setting the size limit to -1 means no limit is enforced.
................................................................................
*/
SQLITE_PRIVATE int sqlite3PagerWalSupported(Pager *pPager){
  const sqlite3_io_methods *pMethods = pPager->fd->pMethods;
  return pMethods->iVersion>=2 && pMethods->xShmOpen!=0;
}

/*



** The caller must be holding a SHARED lock on the database file to call
** this function.
**
** If the pager passed as the first argument is open on a real database
** file (not a temp file or an in-memory database), and the WAL file
** is not already open, make an attempt to open it now. If successful,
** return SQLITE_OK. If an error occurs or the VFS used by the pager does 
** not support the xShmXXX() methods, return an error code. *pisOpen is
** not modified in either case.
**
** If the pager is open on a temp-file (or in-memory database), or if
** the WAL file is already open, set *pisOpen to 1 and return SQLITE_OK
** without doing anything.
*/
SQLITE_PRIVATE int sqlite3PagerOpenWal(
  Pager *pPager,                  /* Pager object */
  int *pisOpen                    /* OUT: Set to true if call is a no-op */
){
  int rc = SQLITE_OK;             /* Return code */

  assert( pPager->state>=PAGER_SHARED );
  assert( (pisOpen==0 && !pPager->tempFile && !pPager->pWal) || *pisOpen==0 );

  if( !pPager->tempFile && !pPager->pWal ){
    if( !sqlite3PagerWalSupported(pPager) ) return SQLITE_CANTOPEN;

    /* Open the connection to the log file. If this operation fails, 
    ** (e.g. due to malloc() failure), unlock the database file and 
    ** return an error code.
    */
    rc = sqlite3WalOpen(pPager->pVfs, pPager->fd,
................................................................................
  ** it may need to be checkpointed before the connection can switch to
  ** rollback mode. Open it now so this can happen.
  */
  if( !pPager->pWal ){
    int logexists = 0;
    rc = sqlite3OsLock(pPager->fd, SQLITE_LOCK_SHARED);
    if( rc==SQLITE_OK ){
      rc = pagerCheckForOrDeleteWAL(pPager, &logexists);
    }
    if( rc==SQLITE_OK && logexists ){
      rc = sqlite3WalOpen(pPager->pVfs, pPager->fd,
                          pPager->zFilename, &pPager->pWal);
    }
  }
    
................................................................................
static int walIndexPage(Wal *pWal, int iPage, volatile u32 **ppPage){
  int rc = SQLITE_OK;

  /* Enlarge the pWal->apWiData[] array if required */
  if( pWal->nWiData<=iPage ){
    int nByte = sizeof(u32 *)*(iPage+1);
    volatile u32 **apNew;
    apNew = (volatile u32 **)sqlite3_realloc((void *)pWal->apWiData, nByte);
    if( !apNew ){
      *ppPage = 0;
      return SQLITE_NOMEM;
    }
    memset((void *)&apNew[pWal->nWiData], 0, sizeof(u32 *)*(iPage+1-pWal->nWiData));
    pWal->apWiData = apNew;
    pWal->nWiData = iPage+1;
  }

  /* Request a pointer to the required page from the VFS */
  if( pWal->apWiData[iPage]==0 ){
    rc = sqlite3OsShmMap(pWal->pDbFd, iPage, WALINDEX_PGSZ, 
................................................................................
static int walLockShared(Wal *pWal, int lockIdx){
  int rc;
  if( pWal->exclusiveMode ) return SQLITE_OK;
  rc = sqlite3OsShmLock(pWal->pDbFd, lockIdx, 1,
                        SQLITE_SHM_LOCK | SQLITE_SHM_SHARED);
  WALTRACE(("WAL%p: acquire SHARED-%s %s\n", pWal,
            walLockName(lockIdx), rc ? "failed" : "ok"));
  VVA_ONLY( pWal->lockError = (u8)(rc!=SQLITE_OK && rc!=SQLITE_BUSY); )
  return rc;
}
static void walUnlockShared(Wal *pWal, int lockIdx){
  if( pWal->exclusiveMode ) return;
  (void)sqlite3OsShmLock(pWal->pDbFd, lockIdx, 1,
                         SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED);
  WALTRACE(("WAL%p: release SHARED-%s\n", pWal, walLockName(lockIdx)));
................................................................................
static int walLockExclusive(Wal *pWal, int lockIdx, int n){
  int rc;
  if( pWal->exclusiveMode ) return SQLITE_OK;
  rc = sqlite3OsShmLock(pWal->pDbFd, lockIdx, n,
                        SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE);
  WALTRACE(("WAL%p: acquire EXCLUSIVE-%s cnt=%d %s\n", pWal,
            walLockName(lockIdx), n, rc ? "failed" : "ok"));
  VVA_ONLY( pWal->lockError = (u8)(rc!=SQLITE_OK && rc!=SQLITE_BUSY); )
  return rc;
}
static void walUnlockExclusive(Wal *pWal, int lockIdx, int n){
  if( pWal->exclusiveMode ) return;
  (void)sqlite3OsShmLock(pWal->pDbFd, lockIdx, n,
                         SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE);
  WALTRACE(("WAL%p: release EXCLUSIVE-%s cnt=%d\n", pWal,
................................................................................
**
** At most only the hash table containing pWal->hdr.mxFrame needs to be
** updated.  Any later hash tables will be automatically cleared when
** pWal->hdr.mxFrame advances to the point where those hash tables are
** actually needed.
*/
static void walCleanupHash(Wal *pWal){
  volatile ht_slot *aHash = 0;    /* Pointer to hash table to clear */
  volatile u32 *aPgno = 0;        /* Page number array for hash table */
  u32 iZero = 0;                  /* frame == (aHash[x]+iZero) */
  int iLimit = 0;                 /* Zero values greater than this */
  int nByte;                      /* Number of bytes to zero in aPgno[] */
  int i;                          /* Used to iterate through aHash[] */

  assert( pWal->writeLock );
  testcase( pWal->hdr.mxFrame==HASHTABLE_NPAGE_ONE-1 );
  testcase( pWal->hdr.mxFrame==HASHTABLE_NPAGE_ONE );
................................................................................
      aHash[i] = 0;
    }
  }
  
  /* Zero the entries in the aPgno array that correspond to frames with
  ** frame numbers greater than pWal->hdr.mxFrame. 
  */
  nByte = (int)((char *)aHash - (char *)&aPgno[iLimit+1]);
  memset((void *)&aPgno[iLimit+1], 0, nByte);

#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
  /* Verify that the every entry in the mapping region is still reachable
  ** via the hash table even after the cleanup.
  */
  if( iLimit ){
................................................................................

/*
** Set an entry in the wal-index that will map database page number
** pPage into WAL frame iFrame.
*/
static int walIndexAppend(Wal *pWal, u32 iFrame, u32 iPage){
  int rc;                         /* Return code */
  u32 iZero = 0;                  /* One less than frame number of aPgno[1] */
  volatile u32 *aPgno = 0;        /* Page number array */
  volatile ht_slot *aHash = 0;    /* Hash table */

  rc = walHashGet(pWal, walFramePage(iFrame), &aHash, &aPgno, &iZero);

  /* Assuming the wal-index file was successfully mapped, populate the
  ** page number array and hash table entry.
  */
  if( rc==SQLITE_OK ){
................................................................................
    idx = iFrame - iZero;
    assert( idx <= HASHTABLE_NSLOT/2 + 1 );
    
    /* If this is the first entry to be added to this hash-table, zero the
    ** entire hash table and aPgno[] array before proceding. 
    */
    if( idx==1 ){
      int nByte = (int)((u8 *)&aHash[HASHTABLE_NSLOT] - (u8 *)&aPgno[1]);
      memset((void*)&aPgno[1], 0, nByte);
    }

    /* If the entry in aPgno[] is already set, then the previous writer
    ** must have exited unexpectedly in the middle of a transaction (after
    ** writing one or more dirty pages to the WAL to free up memory). 
    ** Remove the remnants of that writers uncommitted transaction from 
................................................................................
    }

    /* Write the aPgno[] array entry and the hash-table slot. */
    for(iKey=walHash(iPage); aHash[iKey]; iKey=walNextHash(iKey)){
      assert( nCollide++ < idx );
    }
    aPgno[idx] = iPage;
    aHash[iKey] = (ht_slot)idx;

#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
    /* Verify that the number of entries in the hash table exactly equals
    ** the number of entries in the mapping region.
    */
    {
      int i;           /* Loop counter */
................................................................................
    if( (magic&0xFFFFFFFE)!=WAL_MAGIC 
     || szPage&(szPage-1) 
     || szPage>SQLITE_MAX_PAGE_SIZE 
     || szPage<512 
    ){
      goto finished;
    }
    pWal->hdr.bigEndCksum = (u8)(magic&0x00000001);
    pWal->szPage = (u16)szPage;
    pWal->nCkpt = sqlite3Get4byte(&aBuf[12]);
    memcpy(&pWal->hdr.aSalt, &aBuf[16], 8);

    /* Verify that the WAL header checksum is correct */
    walChecksumBytes(pWal->hdr.bigEndCksum==SQLITE_BIGENDIAN, 
        aBuf, WAL_HDRSIZE-2*4, 0, pWal->hdr.aFrameCksum
    );
................................................................................
      rc = walIndexAppend(pWal, ++iFrame, pgno);
      if( rc!=SQLITE_OK ) break;

      /* If nTruncate is non-zero, this is a commit record. */
      if( nTruncate ){
        pWal->hdr.mxFrame = iFrame;
        pWal->hdr.nPage = nTruncate;
        pWal->hdr.szPage = (u16)szPage;
        aFrameCksum[0] = pWal->hdr.aFrameCksum[0];
        aFrameCksum[1] = pWal->hdr.aFrameCksum[1];
      }
    }

    sqlite3_free(aFrame);
  }
................................................................................
){
  struct Sublist {
    int nList;                    /* Number of elements in aList */
    ht_slot *aList;               /* Pointer to sub-list content */
  };

  const int nList = *pnList;      /* Size of input list */
  int nMerge = 0;                 /* Number of elements in list aMerge */
  ht_slot *aMerge = 0;            /* List to be merged */
  int iList;                      /* Index into input list */
  int iSub = 0;                   /* Index into aSub array */
  struct Sublist aSub[13];        /* Array of sub-lists */

  memset(aSub, 0, sizeof(aSub));
  assert( nList<=HASHTABLE_NPAGE && nList>0 );
  assert( HASHTABLE_NPAGE==(1<<(ArraySize(aSub)-1)) );
................................................................................
    rc = walHashGet(pWal, i, &aHash, &aPgno, &iZero);
    if( rc==SQLITE_OK ){
      int j;                      /* Counter variable */
      int nEntry;                 /* Number of entries in this segment */
      ht_slot *aIndex;            /* Sorted index for this segment */

      aPgno++;
      nEntry = (int)(((i+1)==nSegment)?(int)(iLast-iZero):(u32 *)aHash-(u32 *)aPgno);
      aIndex = &((ht_slot *)&p->aSegment[p->nSegment])[iZero];
      iZero++;
  
      for(j=0; j<nEntry; j++){
        aIndex[j] = (ht_slot)j;
      }
      walMergesort((u32 *)aPgno, aTmp, aIndex, &nEntry);
      p->aSegment[i].iZero = iZero;
      p->aSegment[i].nEntry = nEntry;
      p->aSegment[i].aIndex = aIndex;
      p->aSegment[i].aPgno = (u32 *)aPgno;
    }
................................................................................

    walIndexClose(pWal, isDelete);
    sqlite3OsClose(pWal->pWalFd);
    if( isDelete ){
      sqlite3OsDelete(pWal->pVfs, pWal->zWalName, 0);
    }
    WALTRACE(("WAL%p: closed\n", pWal));
    sqlite3_free((void *)pWal->apWiData);
    sqlite3_free(pWal);
  }
  return rc;
}

/*
** Try to read the wal-index header.  Return 0 on success and 1 if
................................................................................
** If and only if the read is consistent and the header is different from
** pWal->hdr, then pWal->hdr is updated to the content of the new header
** and *pChanged is set to 1.
**
** If the checksum cannot be verified return non-zero. If the header
** is read successfully and the checksum verified, return zero.
*/
static int walIndexTryHdr(Wal *pWal, int *pChanged){
  u32 aCksum[2];                  /* Checksum on the header content */
  WalIndexHdr h1, h2;             /* Two copies of the header content */
  WalIndexHdr volatile *aHdr;     /* Header in shared memory */

  /* The first page of the wal-index must be mapped at this point. */
  assert( pWal->nWiData>0 && pWal->apWiData[0] );

................................................................................
    if( pInfo->aReadMark[mxI]!=mxReadMark
     || memcmp((void *)walIndexHdr(pWal), &pWal->hdr, sizeof(WalIndexHdr))
    ){
      walUnlockShared(pWal, WAL_READ_LOCK(mxI));
      return WAL_RETRY;
    }else{
      assert( mxReadMark<=pWal->hdr.mxFrame );
      pWal->readLock = (i16)mxI;
    }
  }
  return rc;
}

/*
** Begin a read transaction on the database.
................................................................................
    sqlite3Put4byte(&aWalHdr[8], szPage);
    sqlite3Put4byte(&aWalHdr[12], pWal->nCkpt);
    memcpy(&aWalHdr[16], pWal->hdr.aSalt, 8);
    walChecksumBytes(1, aWalHdr, WAL_HDRSIZE-2*4, 0, aCksum);
    sqlite3Put4byte(&aWalHdr[24], aCksum[0]);
    sqlite3Put4byte(&aWalHdr[28], aCksum[1]);
    
    pWal->szPage = (u16)szPage;
    pWal->hdr.bigEndCksum = SQLITE_BIGENDIAN;
    pWal->hdr.aFrameCksum[0] = aCksum[0];
    pWal->hdr.aFrameCksum[1] = aCksum[1];

    rc = sqlite3OsWrite(pWal->pWalFd, aWalHdr, sizeof(aWalHdr), 0);
    WALTRACE(("WAL%p: wal-header write %s\n", pWal, rc ? "failed" : "ok"));
    if( rc!=SQLITE_OK ){
................................................................................
    iFrame++;
    nLast--;
    rc = walIndexAppend(pWal, iFrame, pLast->pgno);
  }

  if( rc==SQLITE_OK ){
    /* Update the private copy of the header. */
    pWal->hdr.szPage = (u16)szPage;
    pWal->hdr.mxFrame = iFrame;
    if( isCommit ){
      pWal->hdr.iChange++;
      pWal->hdr.nPage = nTruncate;
    }
    /* If this is a commit, update the wal-index header too. */
    if( isCommit ){
................................................................................
  BtShared *pBt,          /* The database file */
  Pgno pgno,           /* Number of the page to get */
  MemPage **ppPage     /* Write the page pointer here */
){
  int rc;
  assert( sqlite3_mutex_held(pBt->mutex) );

  if( pgno>btreePagecount(pBt) ){
    rc = SQLITE_CORRUPT_BKPT;
  }else{
    rc = btreeGetPage(pBt, pgno, ppPage, 0);
    if( rc==SQLITE_OK ){
      rc = btreeInitPage(*ppPage);
      if( rc!=SQLITE_OK ){
        releasePage(*ppPage);
      }
    }
  }

  testcase( pgno==0 );
  assert( pgno!=0 || rc==SQLITE_CORRUPT );
  return rc;
}

/*
** Release a MemPage.  This should be called once for each prior
** call to btreeGetPage.
*/
................................................................................

  /* Any read-only or read-write transaction implies a read-lock on 
  ** page 1. So if some other shared-cache client already has a write-lock 
  ** on page 1, the transaction cannot be opened. */
  rc = querySharedCacheTableLock(p, MASTER_ROOT, READ_LOCK);
  if( SQLITE_OK!=rc ) goto trans_begun;

  pBt->initiallyEmpty = (u8)(pBt->nPage==0);
  do {
    /* Call lockBtree() until either pBt->pPage1 is populated or
    ** lockBtree() returns something other than SQLITE_OK. lockBtree()
    ** may return SQLITE_OK but leave pBt->pPage1 set to 0 if after
    ** reading page 1 it discovers that the page-size of the database 
    ** file is not pBt->pageSize. In this case lockBtree() will update
    ** pBt->pageSize to the page-size of the file on disk.
................................................................................
  assert( cursorHoldsMutex(pCur) );
  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
  rc = moveToRoot(pCur);
  if( rc==SQLITE_OK ){
    if( pCur->eState==CURSOR_INVALID ){
      assert( pCur->apPage[pCur->iPage]->nCell==0 );
      *pRes = 1;

    }else{
      assert( pCur->apPage[pCur->iPage]->nCell>0 );
      *pRes = 0;
      rc = moveToLeftmost(pCur);
    }
  }
  return rc;
................................................................................
 
  assert( pBtree->inTrans==TRANS_NONE );
  assert( iVersion==1 || iVersion==2 );

  /* If setting the version fields to 1, do not automatically open the
  ** WAL connection, even if the version fields are currently set to 2.
  */
  pBt->doNotUseWAL = (u8)(iVersion==1);

  rc = sqlite3BtreeBeginTrans(pBtree, 0);
  if( rc==SQLITE_OK ){
    u8 *aData = pBt->pPage1->aData;
    if( aData[18]!=(u8)iVersion || aData[19]!=(u8)iVersion ){
      rc = sqlite3BtreeBeginTrans(pBtree, 2);
      if( rc==SQLITE_OK ){
................................................................................
    if( bCloseTrans ){
      TESTONLY( int rc2 );
      TESTONLY( rc2  = ) sqlite3BtreeCommitPhaseOne(p->pSrc, 0);
      TESTONLY( rc2 |= ) sqlite3BtreeCommitPhaseTwo(p->pSrc);
      assert( rc2==SQLITE_OK );
    }
  
    if( rc==SQLITE_IOERR_NOMEM ){
      rc = SQLITE_NOMEM;
    }
    p->rc = rc;
  }
  if( p->pDestDb ){
    sqlite3_mutex_leave(p->pDestDb->mutex);
  }
  sqlite3BtreeLeave(p->pSrc);
  sqlite3_mutex_leave(p->pSrcDb->mutex);
................................................................................
** an OP_Trace instruction is always inserted by sqlite3VdbeGet() as soon as
** a new VDBE is created.  So we are free to set addr to p->nOp-1 without
** having to double-check to make sure that the result is non-negative. But
** if SQLITE_OMIT_TRACE is defined, the OP_Trace is omitted and we do need to
** check the value of p->nOp-1 before continuing.
*/
SQLITE_PRIVATE VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
  /* C89 specifies that the constant "dummy" will be initialized to all
  ** zeros, which is correct.  MSVC generates a warning, nevertheless. */
  static const VdbeOp dummy;  /* Ignore the MSVC warning about no initializer */
  assert( p->magic==VDBE_MAGIC_INIT );
  if( addr<0 ){
#ifdef SQLITE_OMIT_TRACE
    if( p->nOp==0 ) return (VdbeOp*)&dummy;
#endif
    addr = p->nOp - 1;
  }
................................................................................
  BtCursor *pCrsr;
  int res;
#endif /* local variables moved into u.bl */

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  u.bl.pC = p->apCsr[pOp->p1];
  assert( u.bl.pC!=0 );
  u.bl.res = 1;
  if( (u.bl.pCrsr = u.bl.pC->pCursor)!=0 ){
    rc = sqlite3BtreeFirst(u.bl.pCrsr, &u.bl.res);
    u.bl.pC->atFirst = u.bl.res==0 ?1:0;
    u.bl.pC->deferredMoveto = 0;
    u.bl.pC->cacheStatus = CACHE_STALE;
    u.bl.pC->rowidIsValid = 0;


  }
  u.bl.pC->nullRow = (u8)u.bl.res;
  assert( pOp->p2>0 && pOp->p2<p->nOp );
  if( u.bl.res ){
    pc = pOp->p2 - 1;
  }
  break;
................................................................................
*/
case OP_Checkpoint: {
  rc = sqlite3Checkpoint(db, pOp->p1);
  break;
};  
#endif

#ifndef SQLITE_OMIT_PRAGMA
/* Opcode: JournalMode P1 P2 P3 * P5
**
** Change the journal mode of database P1 to P3. P3 must be one of the
** PAGER_JOURNALMODE_XXX values. If changing between the various rollback
** modes (delete, truncate, persist, off and memory), this is a simple
** operation. No IO is required.
**
................................................................................
  pOut->flags = MEM_Str|MEM_Static|MEM_Term;
  pOut->z = (char *)sqlite3JournalModename(u.cd.eNew);
  pOut->n = sqlite3Strlen30(pOut->z);
  pOut->enc = SQLITE_UTF8;
  sqlite3VdbeChangeEncoding(pOut, encoding);
  break;
};  
#endif /* SQLITE_OMIT_PRAGMA */

#if !defined(SQLITE_OMIT_VACUUM) && !defined(SQLITE_OMIT_ATTACH)
/* Opcode: Vacuum * * * * *
**
** Vacuum the entire database.  This opcode will cause other virtual
** machines to be created and run.  It may not be called from within
** a transaction.
................................................................................
  jrnlSync,      /* xSync */
  jrnlFileSize,  /* xFileSize */
  0,             /* xLock */
  0,             /* xUnlock */
  0,             /* xCheckReservedLock */
  0,             /* xFileControl */
  0,             /* xSectorSize */
  0,             /* xDeviceCharacteristics */
  0,             /* xShmOpen */
  0,             /* xShmLock */
  0,             /* xShmMap */
  0,             /* xShmBarrier */
  0              /* xShmClose */
};

/* 
** Open a journal file.
*/
SQLITE_PRIVATE int sqlite3JournalOpen(
  sqlite3_vfs *pVfs,         /* The VFS to use for actual file I/O */
................................................................................
  memjrnlSync,      /* xSync */
  memjrnlFileSize,  /* xFileSize */
  0,                /* xLock */
  0,                /* xUnlock */
  0,                /* xCheckReservedLock */
  0,                /* xFileControl */
  0,                /* xSectorSize */
  0,                /* xDeviceCharacteristics */
  0,                /* xShmOpen */
  0,                /* xShmLock */
  0,                /* xShmMap */
  0,                /* xShmBarrier */
  0                 /* xShmClose */
};

/* 
** Open a journal file.
*/
SQLITE_PRIVATE void sqlite3MemJournalOpen(sqlite3_file *pJfd){
  MemJournal *p = (MemJournal *)pJfd;
................................................................................
    if( zDb ){
      sqlite3ErrorMsg(pParse, "%s: %s.%s.%s", zErr, zDb, zTab, zCol);
    }else if( zTab ){
      sqlite3ErrorMsg(pParse, "%s: %s.%s", zErr, zTab, zCol);
    }else{
      sqlite3ErrorMsg(pParse, "%s: %s", zErr, zCol);
    }
    pParse->checkSchema = 1;
    pTopNC->nErr++;
  }

  /* If a column from a table in pSrcList is referenced, then record
  ** this fact in the pSrcList.a[].colUsed bitmask.  Column 0 causes
  ** bit 0 to be set.  Column 1 sets bit 1.  And so forth.  If the
  ** column number is greater than the number of bits in the bitmask
................................................................................

    for(j=0, pTabCol=pTab->aCol; j<pTab->nCol; j++, pTabCol++){
      if( sqlite3StrICmp(zColName, pTabCol->zName)==0 ) break;
    }
    if( j>=pTab->nCol ){
      sqlite3ErrorMsg(pParse, "table %s has no column named %s",
        pTab->zName, zColName);
      pParse->checkSchema = 1;
      goto exit_create_index;
    }
    pIndex->aiColumn[i] = j;
    /* Justification of the ALWAYS(pListItem->pExpr->pColl):  Because of
    ** the way the "idxlist" non-terminal is constructed by the parser,
    ** if pListItem->pExpr is not null then either pListItem->pExpr->pColl
    ** must exist or else there must have been an OOM error.  But if there
................................................................................
      }
      if( j>=pTab->nCol ){
        if( sqlite3IsRowid(pColumn->a[i].zName) ){
          keyColumn = i;
        }else{
          sqlite3ErrorMsg(pParse, "table %S has no column named %s",
              pTabList, 0, pColumn->a[i].zName);
          pParse->checkSchema = 1;
          goto insert_cleanup;
        }
      }
    }
  }

  /* If there is no IDLIST term but the table has an integer primary
................................................................................
    Index *pIdx;
    for(pIdx=pTab->pIndex; 
        pIdx && sqlite3StrICmp(pIdx->zName, zIndex); 
        pIdx=pIdx->pNext
    );
    if( !pIdx ){
      sqlite3ErrorMsg(pParse, "no such index: %s", zIndex, 0);
      pParse->checkSchema = 1;
      return SQLITE_ERROR;
    }
    pFrom->pIndex = pIdx;
  }
  return SQLITE_OK;
}

................................................................................
    pTrigger = sqlite3HashFind(&(db->aDb[j].pSchema->trigHash), zName, nName);
    if( pTrigger ) break;
  }
  if( !pTrigger ){
    if( !noErr ){
      sqlite3ErrorMsg(pParse, "no such trigger: %S", pName, 0);
    }
    pParse->checkSchema = 1;
    goto drop_trigger_cleanup;
  }
  sqlite3DropTriggerPtr(pParse, pTrigger);

drop_trigger_cleanup:
  sqlite3SrcListDelete(db, pName);
}
................................................................................
    }
    if( j>=pTab->nCol ){
      if( sqlite3IsRowid(pChanges->a[i].zName) ){
        chngRowid = 1;
        pRowidExpr = pChanges->a[i].pExpr;
      }else{
        sqlite3ErrorMsg(pParse, "no such column: %s", pChanges->a[i].zName);
        pParse->checkSchema = 1;
        goto update_cleanup;
      }
    }
#ifndef SQLITE_OMIT_AUTHORIZATION
    {
      int rc;
      rc = sqlite3AuthCheck(pParse, SQLITE_UPDATE, pTab->zName,
................................................................................
        pIdx->aiColumn[n] = pTerm->u.leftColumn;
        pColl = sqlite3BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
        pIdx->azColl[n] = pColl->zName;
        n++;
      }
    }
  }
  assert( (u32)n==pLevel->plan.nEq );

  /* Add additional columns needed to make the automatic index into
  ** a covering index */
  for(i=0; i<mxBitCol; i++){
    if( extraCols & (((Bitmask)1)<<i) ){
      pIdx->aiColumn[n] = i;
      pIdx->azColl[n] = "BINARY";
................................................................................
    zEndAff = sqlite3DbStrDup(pParse->db, zStartAff);
    addrNxt = pLevel->addrNxt;

    /* If we are doing a reverse order scan on an ascending index, or
    ** a forward order scan on a descending index, interchange the 
    ** start and end terms (pRangeStart and pRangeEnd).
    */
    if( nEq<pIdx->nColumn && bRev==(pIdx->aSortOrder[nEq]==SQLITE_SO_ASC) ){
      SWAP(WhereTerm *, pRangeEnd, pRangeStart);
    }

    testcase( pRangeStart && pRangeStart->eOperator & WO_LE );
    testcase( pRangeStart && pRangeStart->eOperator & WO_GE );
    testcase( pRangeEnd && pRangeEnd->eOperator & WO_LE );
    testcase( pRangeEnd && pRangeEnd->eOperator & WO_GE );
................................................................................
  return rc;
}

/*
** An sqlite3_exec() callback for fts3TableExists.
*/
static int fts3TableExistsCallback(void *pArg, int n, char **pp1, char **pp2){
  UNUSED_PARAMETER(n);
  UNUSED_PARAMETER(pp1);
  UNUSED_PARAMETER(pp2);
  *(int*)pArg = 1;
  return 1;
}

/*
** Determine if a table currently exists in the database.
*/
................................................................................
  if( *pRc ) return;
  zSql = sqlite3_mprintf(
    "SELECT 1 FROM %Q.sqlite_master WHERE name='%q%s'",
    zDb, zName, zSuffix
  );    
  rc = sqlite3_exec(db, zSql, fts3TableExistsCallback, &res, 0);
  sqlite3_free(zSql);
  *pResult = (u8)(res & 0xff);
  if( rc!=SQLITE_ABORT ) *pRc = rc;
}

/*
** This function is the implementation of both the xConnect and xCreate
** methods of the FTS3 virtual table.
**

**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.7.0"
#define SQLITE_VERSION_NUMBER 3007000
#define SQLITE_SOURCE_ID      "2010-06-26 20:25:31 f149b498b6ada3fc9f71ee104c351554c80c7f8a"

/*
** CAPI3REF: Run-Time Library Version Numbers
** KEYWORDS: sqlite3_version, sqlite3_sourceid
**
** These interfaces provide the same information as the [SQLITE_VERSION],
** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros

**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.7.0"
#define SQLITE_VERSION_NUMBER 3007000
#define SQLITE_SOURCE_ID      "2010-07-03 13:59:01 3b20ad03be55613d922d81aec5313327bf4098b9"

/*
** CAPI3REF: Run-Time Library Version Numbers
** KEYWORDS: sqlite3_version, sqlite3_sourceid
**
** These interfaces provide the same information as the [SQLITE_VERSION],
** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros

** autosync.  This will be a pull if the argument is true or a push
** if the argument is false.
*/
void autosync(int flags){
  const char *zUrl;
  const char *zAutosync;
  const char *zPw;

  if( g.fNoSync ){
    return;
  }
  zAutosync = db_get("autosync", 0);
  if( zAutosync ){
    if( (flags & AUTOSYNC_PUSH)!=0 && memcmp(zAutosync,"pull",4)==0 ){
      return;   /* Do not auto-push when autosync=pullonly */
................................................................................
  if( zUrl==0 ){
    return;  /* No default server */
  }
  zPw = db_get("last-sync-pw", 0);
  url_parse(zUrl);
  if( g.urlUser!=0 && g.urlPasswd==0 ){
    g.urlPasswd = mprintf("%s", zPw);










  }
  printf("Autosync:  %s\n", g.urlCanonical);
  url_enable_proxy("via proxy: ");
  client_sync((flags & AUTOSYNC_PUSH)!=0, 1, 0, 0, 0);
}

/*
** This routine processes the command-line argument for push, pull,
** and sync.  If a command-line argument is given, that is the URL
** of a server to sync against.  If no argument is given, use the
** most recently synced URL.  Remember the current URL for next time.
*/
void process_sync_args(void){
  const char *zUrl = 0;
  const char *zPw = 0;

  int urlOptional = find_option("autourl",0,0)!=0;
  g.dontKeepUrl = find_option("once",0,0)!=0;
  url_proxy_options();
  db_find_and_open_repository(1);
  db_open_config(0);
  if( g.argc==2 ){
    zUrl = db_get("last-sync-url", 0);
    zPw = db_get("last-sync-pw", 0);

  }else if( g.argc==3 ){
    zUrl = g.argv[2];
  }
  if( zUrl==0 ){
    if( urlOptional ) exit(0);
    usage("URL");
  }
................................................................................
    }
  }
  user_select();
  if( g.argc==2 ){
    printf("Server:    %s\n", g.urlCanonical);
  }
  url_enable_proxy("via proxy: ");

}

/*
** COMMAND: pull
**
** Usage: %fossil pull ?URL? ?options?
**
................................................................................
** subsequent push, pull, and sync operations.  However, the "--once"
** command-line option makes the URL a one-time-use URL that is not
** saved.
**
** See also: clone, push, sync, remote-url
*/
void pull_cmd(void){
  process_sync_args();
  client_sync(0,1,0,0,0);
}

/*
** COMMAND: push
**
** Usage: %fossil push ?URL? ?options?
**
................................................................................
** subsequent push, pull, and sync operations.  However, the "--once"
** command-line option makes the URL a one-time-use URL that is not
** saved.
**
** See also:  clone, push, pull, remote-url
*/
void sync_cmd(void){
  process_sync_args();
  client_sync(1,1,0,0,0);
}

/*
** COMMAND: remote-url
**
** Usage: %fossil remote-url ?URL|off?
**

** autosync.  This will be a pull if the argument is true or a push
** if the argument is false.
*/
void autosync(int flags){
  const char *zUrl;
  const char *zAutosync;
  const char *zPw;
  int configSync = 0;       /* configuration changes transferred */
  if( g.fNoSync ){
    return;
  }
  zAutosync = db_get("autosync", 0);
  if( zAutosync ){
    if( (flags & AUTOSYNC_PUSH)!=0 && memcmp(zAutosync,"pull",4)==0 ){
      return;   /* Do not auto-push when autosync=pullonly */
................................................................................
  if( zUrl==0 ){
    return;  /* No default server */
  }
  zPw = db_get("last-sync-pw", 0);
  url_parse(zUrl);
  if( g.urlUser!=0 && g.urlPasswd==0 ){
    g.urlPasswd = mprintf("%s", zPw);
  }
  if( (flags & AUTOSYNC_PULL)!=0 && db_get_boolean("auto-shun",1) ){
    /* When doing an automatic pull, also automatically pull shuns from
    ** the server if pull_shuns is enabled.
    **
    ** TODO:  What happens if the shun list gets really big? 
    ** Maybe the shunning list should only be pulled on every 10th
    ** autosync, or something?
    */
    configSync = CONFIGSET_SHUN;
  }
  printf("Autosync:  %s\n", g.urlCanonical);
  url_enable_proxy("via proxy: ");
  client_sync((flags & AUTOSYNC_PUSH)!=0, 1, 0, configSync, 0);
}

/*
** This routine processes the command-line argument for push, pull,
** and sync.  If a command-line argument is given, that is the URL
** of a server to sync against.  If no argument is given, use the
** most recently synced URL.  Remember the current URL for next time.
*/
static int process_sync_args(void){
  const char *zUrl = 0;
  const char *zPw = 0;
  int configSync = 0;
  int urlOptional = find_option("autourl",0,0)!=0;
  g.dontKeepUrl = find_option("once",0,0)!=0;
  url_proxy_options();
  db_find_and_open_repository(1);
  db_open_config(0);
  if( g.argc==2 ){
    zUrl = db_get("last-sync-url", 0);
    zPw = db_get("last-sync-pw", 0);
    if( db_get_boolean("auto-sync",1) ) configSync = CONFIGSET_SHUN;
  }else if( g.argc==3 ){
    zUrl = g.argv[2];
  }
  if( zUrl==0 ){
    if( urlOptional ) exit(0);
    usage("URL");
  }
................................................................................
    }
  }
  user_select();
  if( g.argc==2 ){
    printf("Server:    %s\n", g.urlCanonical);
  }
  url_enable_proxy("via proxy: ");
  return configSync;
}

/*
** COMMAND: pull
**
** Usage: %fossil pull ?URL? ?options?
**
................................................................................
** subsequent push, pull, and sync operations.  However, the "--once"
** command-line option makes the URL a one-time-use URL that is not
** saved.
**
** See also: clone, push, sync, remote-url
*/
void pull_cmd(void){
  int syncFlags = process_sync_args();
  client_sync(0,1,0,syncFlags,0);
}

/*
** COMMAND: push
**
** Usage: %fossil push ?URL? ?options?
**
................................................................................
** subsequent push, pull, and sync operations.  However, the "--once"
** command-line option makes the URL a one-time-use URL that is not
** saved.
**
** See also:  clone, push, pull, remote-url
*/
void sync_cmd(void){
  int syncFlags = process_sync_args();
  client_sync(1,1,0,syncFlags,0);
}

/*
** COMMAND: remote-url
**
** Usage: %fossil remote-url ?URL|off?
**