** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This is the header file for the generic hash-table implemenation
** used in SQLite.  We've modified it slightly to serve as a standalone
** hash table implementation for the full-text indexing module.
**
*/
#ifndef _HASH_H_
#define _HASH_H_

** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This is the header file for the generic hash-table implementation
** used in SQLite.  We've modified it slightly to serve as a standalone
** hash table implementation for the full-text indexing module.
**
*/
#ifndef _HASH_H_
#define _HASH_H_

** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This is the header file for the generic hash-table implemenation
** used in SQLite.  We've modified it slightly to serve as a standalone
** hash table implementation for the full-text indexing module.
**
*/
#ifndef _FTS1_HASH_H_
#define _FTS1_HASH_H_

** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This is the header file for the generic hash-table implementation
** used in SQLite.  We've modified it slightly to serve as a standalone
** hash table implementation for the full-text indexing module.
**
*/
#ifndef _FTS1_HASH_H_
#define _FTS1_HASH_H_

void sqlite3Fts2SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule);
void sqlite3Fts2PorterTokenizerModule(sqlite3_tokenizer_module const**ppModule);
void sqlite3Fts2IcuTokenizerModule(sqlite3_tokenizer_module const**ppModule);

int sqlite3Fts2InitHashTable(sqlite3 *, fts2Hash *, const char *);

/*
** Initialise the fts2 extension. If this extension is built as part
** of the sqlite library, then this function is called directly by
** SQLite. If fts2 is built as a dynamically loadable extension, this
** function is called by the sqlite3_extension_init() entry point.
*/
int sqlite3Fts2Init(sqlite3 *db){
  int rc = SQLITE_OK;
  fts2Hash *pHash = 0;
................................................................................

  sqlite3Fts2SimpleTokenizerModule(&pSimple);
  sqlite3Fts2PorterTokenizerModule(&pPorter);
#ifdef SQLITE_ENABLE_ICU
  sqlite3Fts2IcuTokenizerModule(&pIcu);
#endif

  /* Allocate and initialise the hash-table used to store tokenizers. */
  pHash = sqlite3_malloc(sizeof(fts2Hash));
  if( !pHash ){
    rc = SQLITE_NOMEM;
  }else{
    sqlite3Fts2HashInit(pHash, FTS2_HASH_STRING, 1);
  }

void sqlite3Fts2SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule);
void sqlite3Fts2PorterTokenizerModule(sqlite3_tokenizer_module const**ppModule);
void sqlite3Fts2IcuTokenizerModule(sqlite3_tokenizer_module const**ppModule);

int sqlite3Fts2InitHashTable(sqlite3 *, fts2Hash *, const char *);

/*
** Initialize the fts2 extension. If this extension is built as part
** of the sqlite library, then this function is called directly by
** SQLite. If fts2 is built as a dynamically loadable extension, this
** function is called by the sqlite3_extension_init() entry point.
*/
int sqlite3Fts2Init(sqlite3 *db){
  int rc = SQLITE_OK;
  fts2Hash *pHash = 0;
................................................................................

  sqlite3Fts2SimpleTokenizerModule(&pSimple);
  sqlite3Fts2PorterTokenizerModule(&pPorter);
#ifdef SQLITE_ENABLE_ICU
  sqlite3Fts2IcuTokenizerModule(&pIcu);
#endif

  /* Allocate and initialize the hash-table used to store tokenizers. */
  pHash = sqlite3_malloc(sizeof(fts2Hash));
  if( !pHash ){
    rc = SQLITE_NOMEM;
  }else{
    sqlite3Fts2HashInit(pHash, FTS2_HASH_STRING, 1);
  }

** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This is the header file for the generic hash-table implemenation
** used in SQLite.  We've modified it slightly to serve as a standalone
** hash table implementation for the full-text indexing module.
**
*/
#ifndef _FTS2_HASH_H_
#define _FTS2_HASH_H_

** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This is the header file for the generic hash-table implementation
** used in SQLite.  We've modified it slightly to serve as a standalone
** hash table implementation for the full-text indexing module.
**
*/
#ifndef _FTS2_HASH_H_
#define _FTS2_HASH_H_

}

#endif

/*
** Set up SQL objects in database db used to access the contents of
** the hash table pointed to by argument pHash. The hash table must
** been initialised to use string keys, and to take a private copy 
** of the key when a value is inserted. i.e. by a call similar to:
**
**    sqlite3Fts2HashInit(pHash, FTS2_HASH_STRING, 1);
**
** This function adds a scalar function (see header comment above
** scalarFunc() in this file for details) and, if ENABLE_TABLE is
** defined at compilation time, a temporary virtual table (see header 

}

#endif

/*
** Set up SQL objects in database db used to access the contents of
** the hash table pointed to by argument pHash. The hash table must
** been initialized to use string keys, and to take a private copy 
** of the key when a value is inserted. i.e. by a call similar to:
**
**    sqlite3Fts2HashInit(pHash, FTS2_HASH_STRING, 1);
**
** This function adds a scalar function (see header comment above
** scalarFunc() in this file for details) and, if ENABLE_TABLE is
** defined at compilation time, a temporary virtual table (see header 

  **
  ** then argc is set to 2, and the argv[] array contains pointers
  ** to the strings "arg1" and "arg2".
  **
  ** This method should return either SQLITE_OK (0), or an SQLite error 
  ** code. If SQLITE_OK is returned, then *ppTokenizer should be set
  ** to point at the newly created tokenizer structure. The generic
  ** sqlite3_tokenizer.pModule variable should not be initialised by
  ** this callback. The caller will do so.
  */
  int (*xCreate)(
    int argc,                           /* Size of argv array */
    const char *const*argv,             /* Tokenizer argument strings */
    sqlite3_tokenizer **ppTokenizer     /* OUT: Created tokenizer */
  );

  **
  ** then argc is set to 2, and the argv[] array contains pointers
  ** to the strings "arg1" and "arg2".
  **
  ** This method should return either SQLITE_OK (0), or an SQLite error 
  ** code. If SQLITE_OK is returned, then *ppTokenizer should be set
  ** to point at the newly created tokenizer structure. The generic
  ** sqlite3_tokenizer.pModule variable should not be initialized by
  ** this callback. The caller will do so.
  */
  int (*xCreate)(
    int argc,                           /* Size of argv array */
    const char *const*argv,             /* Tokenizer argument strings */
    sqlite3_tokenizer **ppTokenizer     /* OUT: Created tokenizer */
  );

      sqlite3_bind_int64(pCsr->pStmt, 1, pCsr->iPrevId);
      pCsr->isRequireSeek = 0;
      if( SQLITE_ROW==sqlite3_step(pCsr->pStmt) ){
        return SQLITE_OK;
      }else{
        rc = sqlite3_reset(pCsr->pStmt);
        if( rc==SQLITE_OK && ((Fts3Table *)pCsr->base.pVtab)->zContentTbl==0 ){
          /* If no row was found and no error has occured, then the %_content
          ** table is missing a row that is present in the full-text index.
          ** The data structures are corrupt.  */
          rc = FTS_CORRUPT_VTAB;
          pCsr->isEof = 1;
        }
      }
    }
................................................................................
*/
static void fts3SegReaderCursorFree(Fts3MultiSegReader *pSegcsr){
  sqlite3Fts3SegReaderFinish(pSegcsr);
  sqlite3_free(pSegcsr);
}

/*
** This function retreives the doclist for the specified term (or term
** prefix) from the database.
*/
static int fts3TermSelect(
  Fts3Table *p,                   /* Virtual table handle */
  Fts3PhraseToken *pTok,          /* Token to query for */
  int iColumn,                    /* Column to query (or -ve for all columns) */
  int *pnOut,                     /* OUT: Size of buffer at *ppOut */
................................................................................
void sqlite3Fts3UnicodeTokenizer(sqlite3_tokenizer_module const**ppModule);
#endif
#ifdef SQLITE_ENABLE_ICU
void sqlite3Fts3IcuTokenizerModule(sqlite3_tokenizer_module const**ppModule);
#endif

/*
** Initialise the fts3 extension. If this extension is built as part
** of the sqlite library, then this function is called directly by
** SQLite. If fts3 is built as a dynamically loadable extension, this
** function is called by the sqlite3_extension_init() entry point.
*/
int sqlite3Fts3Init(sqlite3 *db){
  int rc = SQLITE_OK;
  Fts3Hash *pHash = 0;
................................................................................

  rc = sqlite3Fts3InitAux(db);
  if( rc!=SQLITE_OK ) return rc;

  sqlite3Fts3SimpleTokenizerModule(&pSimple);
  sqlite3Fts3PorterTokenizerModule(&pPorter);

  /* Allocate and initialise the hash-table used to store tokenizers. */
  pHash = sqlite3_malloc(sizeof(Fts3Hash));
  if( !pHash ){
    rc = SQLITE_NOMEM;
  }else{
    sqlite3Fts3HashInit(pHash, FTS3_HASH_STRING, 1);
  }

................................................................................
** must be of type FTSQUERY_PHRASE. 
**
** The returned value is either NULL or a pointer to a buffer containing
** a position-list indicating the occurrences of the phrase in column iCol
** of the current row. 
**
** More specifically, the returned buffer contains 1 varint for each 
** occurence of the phrase in the column, stored using the normal (delta+2) 
** compression and is terminated by either an 0x01 or 0x00 byte. For example,
** if the requested column contains "a b X c d X X" and the position-list
** for 'X' is requested, the buffer returned may contain:
**
**     0x04 0x05 0x03 0x01   or   0x04 0x05 0x03 0x00
**
** This function works regardless of whether or not the phrase is deferred,

      sqlite3_bind_int64(pCsr->pStmt, 1, pCsr->iPrevId);
      pCsr->isRequireSeek = 0;
      if( SQLITE_ROW==sqlite3_step(pCsr->pStmt) ){
        return SQLITE_OK;
      }else{
        rc = sqlite3_reset(pCsr->pStmt);
        if( rc==SQLITE_OK && ((Fts3Table *)pCsr->base.pVtab)->zContentTbl==0 ){
          /* If no row was found and no error has occurred, then the %_content
          ** table is missing a row that is present in the full-text index.
          ** The data structures are corrupt.  */
          rc = FTS_CORRUPT_VTAB;
          pCsr->isEof = 1;
        }
      }
    }
................................................................................
*/
static void fts3SegReaderCursorFree(Fts3MultiSegReader *pSegcsr){
  sqlite3Fts3SegReaderFinish(pSegcsr);
  sqlite3_free(pSegcsr);
}

/*
** This function retrieves the doclist for the specified term (or term
** prefix) from the database.
*/
static int fts3TermSelect(
  Fts3Table *p,                   /* Virtual table handle */
  Fts3PhraseToken *pTok,          /* Token to query for */
  int iColumn,                    /* Column to query (or -ve for all columns) */
  int *pnOut,                     /* OUT: Size of buffer at *ppOut */
................................................................................
void sqlite3Fts3UnicodeTokenizer(sqlite3_tokenizer_module const**ppModule);
#endif
#ifdef SQLITE_ENABLE_ICU
void sqlite3Fts3IcuTokenizerModule(sqlite3_tokenizer_module const**ppModule);
#endif

/*
** Initialize the fts3 extension. If this extension is built as part
** of the sqlite library, then this function is called directly by
** SQLite. If fts3 is built as a dynamically loadable extension, this
** function is called by the sqlite3_extension_init() entry point.
*/
int sqlite3Fts3Init(sqlite3 *db){
  int rc = SQLITE_OK;
  Fts3Hash *pHash = 0;
................................................................................

  rc = sqlite3Fts3InitAux(db);
  if( rc!=SQLITE_OK ) return rc;

  sqlite3Fts3SimpleTokenizerModule(&pSimple);
  sqlite3Fts3PorterTokenizerModule(&pPorter);

  /* Allocate and initialize the hash-table used to store tokenizers. */
  pHash = sqlite3_malloc(sizeof(Fts3Hash));
  if( !pHash ){
    rc = SQLITE_NOMEM;
  }else{
    sqlite3Fts3HashInit(pHash, FTS3_HASH_STRING, 1);
  }

................................................................................
** must be of type FTSQUERY_PHRASE. 
**
** The returned value is either NULL or a pointer to a buffer containing
** a position-list indicating the occurrences of the phrase in column iCol
** of the current row. 
**
** More specifically, the returned buffer contains 1 varint for each 
** occurrence of the phrase in the column, stored using the normal (delta+2) 
** compression and is terminated by either an 0x01 or 0x00 byte. For example,
** if the requested column contains "a b X c d X X" and the position-list
** for 'X' is requested, the buffer returned may contain:
**
**     0x04 0x05 0x03 0x01   or   0x04 0x05 0x03 0x00
**
** This function works regardless of whether or not the phrase is deferred,

  int nNest;                          /* Number of nested brackets */
};

/*
** This function is equivalent to the standard isspace() function. 
**
** The standard isspace() can be awkward to use safely, because although it
** is defined to accept an argument of type int, its behaviour when passed
** an integer that falls outside of the range of the unsigned char type
** is undefined (and sometimes, "undefined" means segfault). This wrapper
** is defined to accept an argument of type char, and always returns 0 for
** any values that fall outside of the range of the unsigned char type (i.e.
** negative values).
*/
static int fts3isspace(char c){

  int nNest;                          /* Number of nested brackets */
};

/*
** This function is equivalent to the standard isspace() function. 
**
** The standard isspace() can be awkward to use safely, because although it
** is defined to accept an argument of type int, its behavior when passed
** an integer that falls outside of the range of the unsigned char type
** is undefined (and sometimes, "undefined" means segfault). This wrapper
** is defined to accept an argument of type char, and always returns 0 for
** any values that fall outside of the range of the unsigned char type (i.e.
** negative values).
*/
static int fts3isspace(char c){

** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This is the header file for the generic hash-table implemenation
** used in SQLite.  We've modified it slightly to serve as a standalone
** hash table implementation for the full-text indexing module.
**
*/
#ifndef _FTS3_HASH_H_
#define _FTS3_HASH_H_

** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This is the header file for the generic hash-table implementation
** used in SQLite.  We've modified it slightly to serve as a standalone
** hash table implementation for the full-text indexing module.
**
*/
#ifndef _FTS3_HASH_H_
#define _FTS3_HASH_H_

/*
** Select the fragment of text consisting of nFragment contiguous tokens 
** from column iCol that represent the "best" snippet. The best snippet
** is the snippet with the highest score, where scores are calculated
** by adding:
**
**   (a) +1 point for each occurence of a matchable phrase in the snippet.
**
**   (b) +1000 points for the first occurence of each matchable phrase in 
**       the snippet for which the corresponding mCovered bit is not set.
**
** The selected snippet parameters are stored in structure *pFragment before
** returning. The score of the selected snippet is stored in *piScore
** before returning.
*/
static int fts3BestSnippet(

/*
** Select the fragment of text consisting of nFragment contiguous tokens 
** from column iCol that represent the "best" snippet. The best snippet
** is the snippet with the highest score, where scores are calculated
** by adding:
**
**   (a) +1 point for each occurrence of a matchable phrase in the snippet.
**
**   (b) +1000 points for the first occurrence of each matchable phrase in 
**       the snippet for which the corresponding mCovered bit is not set.
**
** The selected snippet parameters are stored in structure *pFragment before
** returning. The score of the selected snippet is stored in *piScore
** before returning.
*/
static int fts3BestSnippet(

**
** If present, the first argument is the chunksize in bytes to load doclists
** in. The second argument is the minimum doclist size in bytes to use
** incremental loading with.
**
** Whether or not the arguments are present, this command returns a list of
** two integers - the initial chunksize and threshold when the command is
** invoked. This can be used to restore the default behaviour after running
** tests. For example:
**
**    # Override incr-load settings for testing:
**    set cfg [fts3_configure_incr_load $new_chunksize $new_threshold]
**
**    .... run tests ....
**

**
** If present, the first argument is the chunksize in bytes to load doclists
** in. The second argument is the minimum doclist size in bytes to use
** incremental loading with.
**
** Whether or not the arguments are present, this command returns a list of
** two integers - the initial chunksize and threshold when the command is
** invoked. This can be used to restore the default behavior after running
** tests. For example:
**
**    # Override incr-load settings for testing:
**    set cfg [fts3_configure_incr_load $new_chunksize $new_threshold]
**
**    .... run tests ....
**

}

#endif

/*
** Set up SQL objects in database db used to access the contents of
** the hash table pointed to by argument pHash. The hash table must
** been initialised to use string keys, and to take a private copy 
** of the key when a value is inserted. i.e. by a call similar to:
**
**    sqlite3Fts3HashInit(pHash, FTS3_HASH_STRING, 1);
**
** This function adds a scalar function (see header comment above
** scalarFunc() in this file for details) and, if ENABLE_TABLE is
** defined at compilation time, a temporary virtual table (see header 

}

#endif

/*
** Set up SQL objects in database db used to access the contents of
** the hash table pointed to by argument pHash. The hash table must
** been initialized to use string keys, and to take a private copy 
** of the key when a value is inserted. i.e. by a call similar to:
**
**    sqlite3Fts3HashInit(pHash, FTS3_HASH_STRING, 1);
**
** This function adds a scalar function (see header comment above
** scalarFunc() in this file for details) and, if ENABLE_TABLE is
** defined at compilation time, a temporary virtual table (see header 

  **
  ** then argc is set to 2, and the argv[] array contains pointers
  ** to the strings "arg1" and "arg2".
  **
  ** This method should return either SQLITE_OK (0), or an SQLite error 
  ** code. If SQLITE_OK is returned, then *ppTokenizer should be set
  ** to point at the newly created tokenizer structure. The generic
  ** sqlite3_tokenizer.pModule variable should not be initialised by
  ** this callback. The caller will do so.
  */
  int (*xCreate)(
    int argc,                           /* Size of argv array */
    const char *const*argv,             /* Tokenizer argument strings */
    sqlite3_tokenizer **ppTokenizer     /* OUT: Created tokenizer */
  );

  **
  ** then argc is set to 2, and the argv[] array contains pointers
  ** to the strings "arg1" and "arg2".
  **
  ** This method should return either SQLITE_OK (0), or an SQLite error 
  ** code. If SQLITE_OK is returned, then *ppTokenizer should be set
  ** to point at the newly created tokenizer structure. The generic
  ** sqlite3_tokenizer.pModule variable should not be initialized by
  ** this callback. The caller will do so.
  */
  int (*xCreate)(
    int argc,                           /* Size of argv array */
    const char *const*argv,             /* Tokenizer argument strings */
    sqlite3_tokenizer **ppTokenizer     /* OUT: Created tokenizer */
  );

** If so, no action is taken. Otherwise, the codepoint is added to the 
** unicode_tokenizer.aiException[] array. For the purposes of tokenization,
** the return value of sqlite3FtsUnicodeIsalnum() is inverted for all
** codepoints in the aiException[] array.
**
** If a standalone diacritic mark (one that sqlite3FtsUnicodeIsdiacritic()
** identifies as a diacritic) occurs in the zIn/nIn string it is ignored.
** It is not possible to change the behaviour of the tokenizer with respect
** to these codepoints.
*/
static int unicodeAddExceptions(
  unicode_tokenizer *p,           /* Tokenizer to add exceptions to */
  int bAlnum,                     /* Replace Isalnum() return value with this */
  const char *zIn,                /* Array of characters to make exceptions */
  int nIn                         /* Length of z in bytes */

** If so, no action is taken. Otherwise, the codepoint is added to the 
** unicode_tokenizer.aiException[] array. For the purposes of tokenization,
** the return value of sqlite3FtsUnicodeIsalnum() is inverted for all
** codepoints in the aiException[] array.
**
** If a standalone diacritic mark (one that sqlite3FtsUnicodeIsdiacritic()
** identifies as a diacritic) occurs in the zIn/nIn string it is ignored.
** It is not possible to change the behavior of the tokenizer with respect
** to these codepoints.
*/
static int unicodeAddExceptions(
  unicode_tokenizer *p,           /* Tokenizer to add exceptions to */
  int bAlnum,                     /* Replace Isalnum() return value with this */
  const char *zIn,                /* Array of characters to make exceptions */
  int nIn                         /* Length of z in bytes */

    comparision operator "REGEXP", based on the regular expression functions
    provided by the ICU library. The syntax of the operator is as described
    in SQLite documentation:

        <string> REGEXP <re-pattern>

    This extension uses the ICU defaults for regular expression matching
    behaviour. Specifically, this means that:

        * Matching is case-sensitive,
        * Regular expression comments are not allowed within patterns, and
        * The '^' and '$' characters match the beginning and end of the
          <string> argument, not the beginning and end of lines within
          the <string> argument.

    comparision operator "REGEXP", based on the regular expression functions
    provided by the ICU library. The syntax of the operator is as described
    in SQLite documentation:

        <string> REGEXP <re-pattern>

    This extension uses the ICU defaults for regular expression matching
    behavior. Specifically, this means that:

        * Matching is case-sensitive,
        * Regular expression comments are not allowed within patterns, and
        * The '^' and '$' characters match the beginning and end of the
          <string> argument, not the beginning and end of lines within
          the <string> argument.

static int rtreeDeleteRowid(Rtree *pRtree, sqlite3_int64 iDelete){
  int rc;                         /* Return code */
  RtreeNode *pLeaf = 0;           /* Leaf node containing record iDelete */
  int iCell;                      /* Index of iDelete cell in pLeaf */
  RtreeNode *pRoot;               /* Root node of rtree structure */


  /* Obtain a reference to the root node to initialise Rtree.iDepth */
  rc = nodeAcquire(pRtree, 1, 0, &pRoot);

  /* Obtain a reference to the leaf node that contains the entry 
  ** about to be deleted. 
  */
  if( rc==SQLITE_OK ){
    rc = findLeafNode(pRtree, iDelete, &pLeaf);

static int rtreeDeleteRowid(Rtree *pRtree, sqlite3_int64 iDelete){
  int rc;                         /* Return code */
  RtreeNode *pLeaf = 0;           /* Leaf node containing record iDelete */
  int iCell;                      /* Index of iDelete cell in pLeaf */
  RtreeNode *pRoot;               /* Root node of rtree structure */


  /* Obtain a reference to the root node to initialize Rtree.iDepth */
  rc = nodeAcquire(pRtree, 1, 0, &pRoot);

  /* Obtain a reference to the leaf node that contains the entry 
  ** about to be deleted. 
  */
  if( rc==SQLITE_OK ){
    rc = findLeafNode(pRtree, iDelete, &pLeaf);

    assert( z && zName );
    if( sqlite3StrICmp(z, zName)==0 ){
      zErrDyn = sqlite3MPrintf(db, "database %s is already in use", zName);
      goto attach_error;
    }
  }

  /* Allocate the new entry in the db->aDb[] array and initialise the schema
  ** hash tables.
  */
  if( db->aDb==db->aDbStatic ){
    aNew = sqlite3DbMallocRaw(db, sizeof(db->aDb[0])*3 );
    if( aNew==0 ) return;
    memcpy(aNew, db->aDb, sizeof(db->aDb[0])*2);
  }else{
................................................................................
  }
  db->aDb = aNew;
  aNew = &db->aDb[db->nDb];
  memset(aNew, 0, sizeof(*aNew));

  /* Open the database file. If the btree is successfully opened, use
  ** it to obtain the database schema. At this point the schema may
  ** or may not be initialised.
  */
  flags = db->openFlags;
  rc = sqlite3ParseUri(db->pVfs->zName, zFile, &flags, &pVfs, &zPath, &zErr);
  if( rc!=SQLITE_OK ){
    if( rc==SQLITE_NOMEM ) db->mallocFailed = 1;
    sqlite3_result_error(context, zErr, -1);
    sqlite3_free(zErr);

    assert( z && zName );
    if( sqlite3StrICmp(z, zName)==0 ){
      zErrDyn = sqlite3MPrintf(db, "database %s is already in use", zName);
      goto attach_error;
    }
  }

  /* Allocate the new entry in the db->aDb[] array and initialize the schema
  ** hash tables.
  */
  if( db->aDb==db->aDbStatic ){
    aNew = sqlite3DbMallocRaw(db, sizeof(db->aDb[0])*3 );
    if( aNew==0 ) return;
    memcpy(aNew, db->aDb, sizeof(db->aDb[0])*2);
  }else{
................................................................................
  }
  db->aDb = aNew;
  aNew = &db->aDb[db->nDb];
  memset(aNew, 0, sizeof(*aNew));

  /* Open the database file. If the btree is successfully opened, use
  ** it to obtain the database schema. At this point the schema may
  ** or may not be initialized.
  */
  flags = db->openFlags;
  rc = sqlite3ParseUri(db->pVfs->zName, zFile, &flags, &pVfs, &zPath, &zErr);
  if( rc!=SQLITE_OK ){
    if( rc==SQLITE_NOMEM ) db->mallocFailed = 1;
    sqlite3_result_error(context, zErr, -1);
    sqlite3_free(zErr);

#define BITVEC_NPTR      (BITVEC_USIZE/sizeof(Bitvec *))


/*
** A bitmap is an instance of the following structure.
**
** This bitmap records the existance of zero or more bits
** with values between 1 and iSize, inclusive.
**
** There are three possible representations of the bitmap.
** If iSize<=BITVEC_NBIT, then Bitvec.u.aBitmap[] is a straight
** bitmap.  The least significant bit is bit 1.
**
** If iSize>BITVEC_NBIT and iDivisor==0 then Bitvec.u.aHash[] is

#define BITVEC_NPTR      (BITVEC_USIZE/sizeof(Bitvec *))


/*
** A bitmap is an instance of the following structure.
**
** This bitmap records the existence of zero or more bits
** with values between 1 and iSize, inclusive.
**
** There are three possible representations of the bitmap.
** If iSize<=BITVEC_NBIT, then Bitvec.u.aBitmap[] is a straight
** bitmap.  The least significant bit is bit 1.
**
** If iSize>BITVEC_NBIT and iDivisor==0 then Bitvec.u.aHash[] is

** may only be called if it is guaranteed that the b-tree mutex is already
** held.
**
** This is useful in one special case in the backup API code where it is
** known that the shared b-tree mutex is held, but the mutex on the 
** database handle that owns *p is not. In this case if sqlite3BtreeEnter()
** were to be called, it might collide with some other operation on the
** database handle that owns *p, causing undefined behaviour.
*/
int sqlite3BtreeGetReserveNoMutex(Btree *p){
  assert( sqlite3_mutex_held(p->pBt->mutex) );
  return p->pBt->pageSize - p->pBt->usableSize;
}
#endif /* SQLITE_HAS_CODEC || SQLITE_DEBUG */

................................................................................
      /* If the database supports auto-vacuum, and the second or subsequent
      ** overflow page is being allocated, add an entry to the pointer-map
      ** for that page now. 
      **
      ** If this is the first overflow page, then write a partial entry 
      ** to the pointer-map. If we write nothing to this pointer-map slot,
      ** then the optimistic overflow chain processing in clearCell()
      ** may misinterpret the uninitialised values and delete the
      ** wrong pages from the database.
      */
      if( pBt->autoVacuum && rc==SQLITE_OK ){
        u8 eType = (pgnoPtrmap?PTRMAP_OVERFLOW2:PTRMAP_OVERFLOW1);
        ptrmapPut(pBt, pgnoOvfl, eType, pgnoPtrmap, &rc);
        if( rc ){
          releasePage(pOvfl);
................................................................................
    idx = ++pCur->aiIdx[pCur->iPage];
  }else{
    assert( pPage->leaf );
  }
  insertCell(pPage, idx, newCell, szNew, 0, 0, &rc);
  assert( rc!=SQLITE_OK || pPage->nCell>0 || pPage->nOverflow>0 );

  /* If no error has occured and pPage has an overflow cell, call balance() 
  ** to redistribute the cells within the tree. Since balance() may move
  ** the cursor, zero the BtCursor.info.nSize and BtCursor.validNKey
  ** variables.
  **
  ** Previous versions of SQLite called moveToRoot() to move the cursor
  ** back to the root page as balance() used to invalidate the contents
  ** of BtCursor.apPage[] and BtCursor.aiIdx[]. Instead of doing that,

** may only be called if it is guaranteed that the b-tree mutex is already
** held.
**
** This is useful in one special case in the backup API code where it is
** known that the shared b-tree mutex is held, but the mutex on the 
** database handle that owns *p is not. In this case if sqlite3BtreeEnter()
** were to be called, it might collide with some other operation on the
** database handle that owns *p, causing undefined behavior.
*/
int sqlite3BtreeGetReserveNoMutex(Btree *p){
  assert( sqlite3_mutex_held(p->pBt->mutex) );
  return p->pBt->pageSize - p->pBt->usableSize;
}
#endif /* SQLITE_HAS_CODEC || SQLITE_DEBUG */

................................................................................
      /* If the database supports auto-vacuum, and the second or subsequent
      ** overflow page is being allocated, add an entry to the pointer-map
      ** for that page now. 
      **
      ** If this is the first overflow page, then write a partial entry 
      ** to the pointer-map. If we write nothing to this pointer-map slot,
      ** then the optimistic overflow chain processing in clearCell()
      ** may misinterpret the uninitialized values and delete the
      ** wrong pages from the database.
      */
      if( pBt->autoVacuum && rc==SQLITE_OK ){
        u8 eType = (pgnoPtrmap?PTRMAP_OVERFLOW2:PTRMAP_OVERFLOW1);
        ptrmapPut(pBt, pgnoOvfl, eType, pgnoPtrmap, &rc);
        if( rc ){
          releasePage(pOvfl);
................................................................................
    idx = ++pCur->aiIdx[pCur->iPage];
  }else{
    assert( pPage->leaf );
  }
  insertCell(pPage, idx, newCell, szNew, 0, 0, &rc);
  assert( rc!=SQLITE_OK || pPage->nCell>0 || pPage->nOverflow>0 );

  /* If no error has occurred and pPage has an overflow cell, call balance() 
  ** to redistribute the cells within the tree. Since balance() may move
  ** the cursor, zero the BtCursor.info.nSize and BtCursor.validNKey
  ** variables.
  **
  ** Previous versions of SQLite called moveToRoot() to move the cursor
  ** back to the root page as balance() used to invalidate the contents
  ** of BtCursor.apPage[] and BtCursor.aiIdx[]. Instead of doing that,

    );
  }
#endif

  /* Drop all SQLITE_MASTER table and index entries that refer to the
  ** table. The program name loops through the master table and deletes
  ** every row that refers to a table of the same name as the one being
  ** dropped. Triggers are handled seperately because a trigger can be
  ** created in the temp database that refers to a table in another
  ** database.
  */
  sqlite3NestedParse(pParse, 
      "DELETE FROM %Q.%s WHERE tbl_name=%Q and type!='trigger'",
      pDb->zName, SCHEMA_TABLE(iDb), pTab->zName);
  if( !isView && !IsVirtual(pTab) ){
................................................................................
      if( k==pIdx->nColumn ){
        if( pIdx->onError!=pIndex->onError ){
          /* This constraint creates the same index as a previous
          ** constraint specified somewhere in the CREATE TABLE statement.
          ** However the ON CONFLICT clauses are different. If both this 
          ** constraint and the previous equivalent constraint have explicit
          ** ON CONFLICT clauses this is an error. Otherwise, use the
          ** explicitly specified behaviour for the index.
          */
          if( !(pIdx->onError==OE_Default || pIndex->onError==OE_Default) ){
            sqlite3ErrorMsg(pParse, 
                "conflicting ON CONFLICT clauses specified", 0);
          }
          if( pIdx->onError==OE_Default ){
            pIdx->onError = pIndex->onError;

    );
  }
#endif

  /* Drop all SQLITE_MASTER table and index entries that refer to the
  ** table. The program name loops through the master table and deletes
  ** every row that refers to a table of the same name as the one being
  ** dropped. Triggers are handled separately because a trigger can be
  ** created in the temp database that refers to a table in another
  ** database.
  */
  sqlite3NestedParse(pParse, 
      "DELETE FROM %Q.%s WHERE tbl_name=%Q and type!='trigger'",
      pDb->zName, SCHEMA_TABLE(iDb), pTab->zName);
  if( !isView && !IsVirtual(pTab) ){
................................................................................
      if( k==pIdx->nColumn ){
        if( pIdx->onError!=pIndex->onError ){
          /* This constraint creates the same index as a previous
          ** constraint specified somewhere in the CREATE TABLE statement.
          ** However the ON CONFLICT clauses are different. If both this 
          ** constraint and the previous equivalent constraint have explicit
          ** ON CONFLICT clauses this is an error. Otherwise, use the
          ** explicitly specified behavior for the index.
          */
          if( !(pIdx->onError==OE_Default || pIndex->onError==OE_Default) ){
            sqlite3ErrorMsg(pParse, 
                "conflicting ON CONFLICT clauses specified", 0);
          }
          if( pIdx->onError==OE_Default ){
            pIdx->onError = pIndex->onError;

  Vdbe *v = pParse->pVdbe;
  int op = 0;
  int regFree1 = 0;
  int regFree2 = 0;
  int r1, r2;

  assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
  if( NEVER(v==0) )     return;  /* Existance of VDBE checked by caller */
  if( NEVER(pExpr==0) ) return;  /* No way this can happen */
  op = pExpr->op;
  switch( op ){
    case TK_AND: {
      int d2 = sqlite3VdbeMakeLabel(v);
      testcase( jumpIfNull==0 );
      sqlite3ExprCachePush(pParse);
................................................................................
  Vdbe *v = pParse->pVdbe;
  int op = 0;
  int regFree1 = 0;
  int regFree2 = 0;
  int r1, r2;

  assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
  if( NEVER(v==0) ) return; /* Existance of VDBE checked by caller */
  if( pExpr==0 )    return;

  /* The value of pExpr->op and op are related as follows:
  **
  **       pExpr->op            op
  **       ---------          ----------
  **       TK_ISNULL          OP_NotNull

  Vdbe *v = pParse->pVdbe;
  int op = 0;
  int regFree1 = 0;
  int regFree2 = 0;
  int r1, r2;

  assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
  if( NEVER(v==0) )     return;  /* Existence of VDBE checked by caller */
  if( NEVER(pExpr==0) ) return;  /* No way this can happen */
  op = pExpr->op;
  switch( op ){
    case TK_AND: {
      int d2 = sqlite3VdbeMakeLabel(v);
      testcase( jumpIfNull==0 );
      sqlite3ExprCachePush(pParse);
................................................................................
  Vdbe *v = pParse->pVdbe;
  int op = 0;
  int regFree1 = 0;
  int regFree2 = 0;
  int r1, r2;

  assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
  if( NEVER(v==0) ) return; /* Existence of VDBE checked by caller */
  if( pExpr==0 )    return;

  /* The value of pExpr->op and op are related as follows:
  **
  **       pExpr->op            op
  **       ---------          ----------
  **       TK_ISNULL          OP_NotNull

** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This is the header file for the generic hash-table implemenation
** used in SQLite.
*/
#ifndef _SQLITE_HASH_H_
#define _SQLITE_HASH_H_

/* Forward declarations of structures. */
typedef struct Hash Hash;

** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This is the header file for the generic hash-table implementation
** used in SQLite.
*/
#ifndef _SQLITE_HASH_H_
#define _SQLITE_HASH_H_

/* Forward declarations of structures. */
typedef struct Hash Hash;

  if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
    sqlite3_mutex_leave(db->mutex);
    return;
  }

  /* If we reach this point, it means that the database connection has
  ** closed all sqlite3_stmt and sqlite3_backup objects and has been
  ** pased to sqlite3_close (meaning that it is a zombie).  Therefore,
  ** go ahead and free all resources.
  */

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

  /* Close all database connections */

  if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
    sqlite3_mutex_leave(db->mutex);
    return;
  }

  /* If we reach this point, it means that the database connection has
  ** closed all sqlite3_stmt and sqlite3_backup objects and has been
  ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
  ** go ahead and free all resources.
  */

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

  /* Close all database connections */

/*
** Many system calls are accessed through pointer-to-functions so that
** they may be overridden at runtime to facilitate fault injection during
** testing and sandboxing.  The following array holds the names and pointers
** to all overrideable system calls.
*/
static struct unix_syscall {
  const char *zName;            /* Name of the sytem call */
  sqlite3_syscall_ptr pCurrent; /* Current value of the system call */
  sqlite3_syscall_ptr pDefault; /* Default value */
} aSyscall[] = {
  { "open",         (sqlite3_syscall_ptr)posixOpen,  0  },
#define osOpen      ((int(*)(const char*,int,int))aSyscall[0].pCurrent)

  { "close",        (sqlite3_syscall_ptr)close,      0  },
................................................................................

/******************* End of the no-op lock implementation *********************
******************************************************************************/

/******************************************************************************
************************* Begin dot-file Locking ******************************
**
** The dotfile locking implementation uses the existance of separate lock
** files (really a directory) to control access to the database.  This works
** on just about every filesystem imaginable.  But there are serious downsides:
**
**    (1)  There is zero concurrency.  A single reader blocks all other
**         connections from reading or writing the database.
**
**    (2)  An application crash or power loss can leave stale lock files
................................................................................
**         sitting around that need to be cleared manually.
**
** Nevertheless, a dotlock is an appropriate locking mode for use if no
** other locking strategy is available.
**
** Dotfile locking works by creating a subdirectory in the same directory as
** the database and with the same name but with a ".lock" extension added.
** The existance of a lock directory implies an EXCLUSIVE lock.  All other
** lock types (SHARED, RESERVED, PENDING) are mapped into EXCLUSIVE.
*/

/*
** The file suffix added to the data base filename in order to create the
** lock directory.
*/
................................................................................
  SimulateIOError( rc=1 );
  if( rc ){
    pFile->lastErrno = errno;
    return unixLogError(SQLITE_IOERR_FSYNC, "full_fsync", pFile->zPath);
  }

  /* Also fsync the directory containing the file if the DIRSYNC flag
  ** is set.  This is a one-time occurrance.  Many systems (examples: AIX)
  ** are unable to fsync a directory, so ignore errors on the fsync.
  */
  if( pFile->ctrlFlags & UNIXFILE_DIRSYNC ){
    int dirfd;
    OSTRACE(("DIRSYNC %s (have_fullfsync=%d fullsync=%d)\n", pFile->zPath,
            HAVE_FULLFSYNC, isFullsync));
    rc = osOpenDirectory(pFile->zPath, &dirfd);
................................................................................
#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
    || pLockingStyle == &nfsIoMethods
#endif
  ){
    unixEnterMutex();
    rc = findInodeInfo(pNew, &pNew->pInode);
    if( rc!=SQLITE_OK ){
      /* If an error occured in findInodeInfo(), close the file descriptor
      ** immediately, before releasing the mutex. findInodeInfo() may fail
      ** in two scenarios:
      **
      **   (a) A call to fstat() failed.
      **   (b) A malloc failed.
      **
      ** Scenario (b) may only occur if the process is holding no other
................................................................................
    }
  }
#endif
  return rc;
}

/*
** Test the existance of or access permissions of file zPath. The
** test performed depends on the value of flags:
**
**     SQLITE_ACCESS_EXISTS: Return 1 if the file exists
**     SQLITE_ACCESS_READWRITE: Return 1 if the file is read and writable.
**     SQLITE_ACCESS_READONLY: Return 1 if the file is readable.
**
** Otherwise return 0.

/*
** Many system calls are accessed through pointer-to-functions so that
** they may be overridden at runtime to facilitate fault injection during
** testing and sandboxing.  The following array holds the names and pointers
** to all overrideable system calls.
*/
static struct unix_syscall {
  const char *zName;            /* Name of the system call */
  sqlite3_syscall_ptr pCurrent; /* Current value of the system call */
  sqlite3_syscall_ptr pDefault; /* Default value */
} aSyscall[] = {
  { "open",         (sqlite3_syscall_ptr)posixOpen,  0  },
#define osOpen      ((int(*)(const char*,int,int))aSyscall[0].pCurrent)

  { "close",        (sqlite3_syscall_ptr)close,      0  },
................................................................................

/******************* End of the no-op lock implementation *********************
******************************************************************************/

/******************************************************************************
************************* Begin dot-file Locking ******************************
**
** The dotfile locking implementation uses the existence of separate lock
** files (really a directory) to control access to the database.  This works
** on just about every filesystem imaginable.  But there are serious downsides:
**
**    (1)  There is zero concurrency.  A single reader blocks all other
**         connections from reading or writing the database.
**
**    (2)  An application crash or power loss can leave stale lock files
................................................................................
**         sitting around that need to be cleared manually.
**
** Nevertheless, a dotlock is an appropriate locking mode for use if no
** other locking strategy is available.
**
** Dotfile locking works by creating a subdirectory in the same directory as
** the database and with the same name but with a ".lock" extension added.
** The existence of a lock directory implies an EXCLUSIVE lock.  All other
** lock types (SHARED, RESERVED, PENDING) are mapped into EXCLUSIVE.
*/

/*
** The file suffix added to the data base filename in order to create the
** lock directory.
*/
................................................................................
  SimulateIOError( rc=1 );
  if( rc ){
    pFile->lastErrno = errno;
    return unixLogError(SQLITE_IOERR_FSYNC, "full_fsync", pFile->zPath);
  }

  /* Also fsync the directory containing the file if the DIRSYNC flag
  ** is set.  This is a one-time occurrence.  Many systems (examples: AIX)
  ** are unable to fsync a directory, so ignore errors on the fsync.
  */
  if( pFile->ctrlFlags & UNIXFILE_DIRSYNC ){
    int dirfd;
    OSTRACE(("DIRSYNC %s (have_fullfsync=%d fullsync=%d)\n", pFile->zPath,
            HAVE_FULLFSYNC, isFullsync));
    rc = osOpenDirectory(pFile->zPath, &dirfd);
................................................................................
#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
    || pLockingStyle == &nfsIoMethods
#endif
  ){
    unixEnterMutex();
    rc = findInodeInfo(pNew, &pNew->pInode);
    if( rc!=SQLITE_OK ){
      /* If an error occurred in findInodeInfo(), close the file descriptor
      ** immediately, before releasing the mutex. findInodeInfo() may fail
      ** in two scenarios:
      **
      **   (a) A call to fstat() failed.
      **   (b) A malloc failed.
      **
      ** Scenario (b) may only occur if the process is holding no other
................................................................................
    }
  }
#endif
  return rc;
}

/*
** Test the existence of or access permissions of file zPath. The
** test performed depends on the value of flags:
**
**     SQLITE_ACCESS_EXISTS: Return 1 if the file exists
**     SQLITE_ACCESS_READWRITE: Return 1 if the file is read and writable.
**     SQLITE_ACCESS_READONLY: Return 1 if the file is readable.
**
** Otherwise return 0.

/*
** Many system calls are accessed through pointer-to-functions so that
** they may be overridden at runtime to facilitate fault injection during
** testing and sandboxing.  The following array holds the names and pointers
** to all overrideable system calls.
*/
static struct win_syscall {
  const char *zName;            /* Name of the sytem call */
  sqlite3_syscall_ptr pCurrent; /* Current value of the system call */
  sqlite3_syscall_ptr pDefault; /* Default value */
} aSyscall[] = {
#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
  { "AreFileApisANSI",         (SYSCALL)AreFileApisANSI,         0 },
#else
  { "AreFileApisANSI",         (SYSCALL)0,                       0 },
................................................................................
  upperBits = (LONG)((iOffset>>32) & 0x7fffffff);
  lowerBits = (LONG)(iOffset & 0xffffffff);

  /* API oddity: If successful, SetFilePointer() returns a dword 
  ** containing the lower 32-bits of the new file-offset. Or, if it fails,
  ** it returns INVALID_SET_FILE_POINTER. However according to MSDN, 
  ** INVALID_SET_FILE_POINTER may also be a valid new offset. So to determine 
  ** whether an error has actually occured, it is also necessary to call 
  ** GetLastError().
  */
  dwRet = osSetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);

  if( (dwRet==INVALID_SET_FILE_POINTER
      && ((lastErrno = osGetLastError())!=NO_ERROR)) ){
    pFile->lastErrno = lastErrno;
................................................................................
*/
static int winWrite(
  sqlite3_file *id,               /* File to write into */
  const void *pBuf,               /* The bytes to be written */
  int amt,                        /* Number of bytes to write */
  sqlite3_int64 offset            /* Offset into the file to begin writing at */
){
  int rc = 0;                     /* True if error has occured, else false */
  winFile *pFile = (winFile*)id;  /* File handle */
  int nRetry = 0;                 /* Number of retries */

  assert( amt>0 );
  assert( pFile );
  SimulateIOError(return SQLITE_IOERR_WRITE);
  SimulateDiskfullError(return SQLITE_FULL);
................................................................................
  }
  sqlite3_free(zConverted);
  OSTRACE(("DELETE \"%s\" %s\n", zFilename, (rc ? "failed" : "ok" )));
  return rc;
}

/*
** Check the existance and status of a file.
*/
static int winAccess(
  sqlite3_vfs *pVfs,         /* Not used on win32 */
  const char *zFilename,     /* Name of file to check */
  int flags,                 /* Type of test to make on this file */
  int *pResOut               /* OUT: Result */
){

/*
** Many system calls are accessed through pointer-to-functions so that
** they may be overridden at runtime to facilitate fault injection during
** testing and sandboxing.  The following array holds the names and pointers
** to all overrideable system calls.
*/
static struct win_syscall {
  const char *zName;            /* Name of the system call */
  sqlite3_syscall_ptr pCurrent; /* Current value of the system call */
  sqlite3_syscall_ptr pDefault; /* Default value */
} aSyscall[] = {
#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
  { "AreFileApisANSI",         (SYSCALL)AreFileApisANSI,         0 },
#else
  { "AreFileApisANSI",         (SYSCALL)0,                       0 },
................................................................................
  upperBits = (LONG)((iOffset>>32) & 0x7fffffff);
  lowerBits = (LONG)(iOffset & 0xffffffff);

  /* API oddity: If successful, SetFilePointer() returns a dword 
  ** containing the lower 32-bits of the new file-offset. Or, if it fails,
  ** it returns INVALID_SET_FILE_POINTER. However according to MSDN, 
  ** INVALID_SET_FILE_POINTER may also be a valid new offset. So to determine 
  ** whether an error has actually occurred, it is also necessary to call 
  ** GetLastError().
  */
  dwRet = osSetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);

  if( (dwRet==INVALID_SET_FILE_POINTER
      && ((lastErrno = osGetLastError())!=NO_ERROR)) ){
    pFile->lastErrno = lastErrno;
................................................................................
*/
static int winWrite(
  sqlite3_file *id,               /* File to write into */
  const void *pBuf,               /* The bytes to be written */
  int amt,                        /* Number of bytes to write */
  sqlite3_int64 offset            /* Offset into the file to begin writing at */
){
  int rc = 0;                     /* True if error has occurred, else false */
  winFile *pFile = (winFile*)id;  /* File handle */
  int nRetry = 0;                 /* Number of retries */

  assert( amt>0 );
  assert( pFile );
  SimulateIOError(return SQLITE_IOERR_WRITE);
  SimulateDiskfullError(return SQLITE_FULL);
................................................................................
  }
  sqlite3_free(zConverted);
  OSTRACE(("DELETE \"%s\" %s\n", zFilename, (rc ? "failed" : "ok" )));
  return rc;
}

/*
** Check the existence and status of a file.
*/
static int winAccess(
  sqlite3_vfs *pVfs,         /* Not used on win32 */
  const char *zFilename,     /* Name of file to check */
  int flags,                 /* Type of test to make on this file */
  int *pResOut               /* OUT: Result */
){

**    by finalizing the journal file. Once in WRITER_FINISHED state, it is 
**    not possible to modify the database further. At this point, the upper 
**    layer must either commit or rollback the transaction.
**
**    * A write transaction is active.
**    * An EXCLUSIVE or greater lock is held on the database file.
**    * All writing and syncing of journal and database data has finished.
**      If no error occured, all that remains is to finalize the journal to
**      commit the transaction. If an error did occur, the caller will need
**      to rollback the transaction. 
**
**  ERROR:
**
**    The ERROR state is entered when an IO or disk-full error (including
**    SQLITE_IOERR_NOMEM) occurs at a point in the code that makes it 
................................................................................
**   The flag is cleared as soon as the journal file is finalized (either
**   by PagerCommitPhaseTwo or PagerRollback). If an IO error prevents the
**   journal file from being successfully finalized, the setMaster flag
**   is cleared anyway (and the pager will move to ERROR state).
**
** doNotSpill, doNotSyncSpill
**
**   These two boolean variables control the behaviour of cache-spills
**   (calls made by the pcache module to the pagerStress() routine to
**   write cached data to the file-system in order to free up memory).
**
**   When doNotSpill is non-zero, writing to the database from pagerStress()
**   is disabled altogether. This is done in a very obscure case that
**   comes up during savepoint rollback that requires the pcache module
**   to allocate a new page to prevent the journal file from being written
................................................................................
  ){
    memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
    put32bits(&zHeader[sizeof(aJournalMagic)], 0xffffffff);
  }else{
    memset(zHeader, 0, sizeof(aJournalMagic)+4);
  }

  /* The random check-hash initialiser */ 
  sqlite3_randomness(sizeof(pPager->cksumInit), &pPager->cksumInit);
  put32bits(&zHeader[sizeof(aJournalMagic)+4], pPager->cksumInit);
  /* The initial database size */
  put32bits(&zHeader[sizeof(aJournalMagic)+8], pPager->dbOrigSize);
  /* The assumed sector size for this process */
  put32bits(&zHeader[sizeof(aJournalMagic)+12], pPager->sectorSize);

................................................................................
**      be necessary to write the current content out to the sub-journal
**      (as determined by function subjRequiresPage()).
**
** If the condition asserted by this function were not true, and the
** dirty page were to be discarded from the cache via the pagerStress()
** routine, pagerStress() would not write the current page content to
** the database file. If a savepoint transaction were rolled back after
** this happened, the correct behaviour would be to restore the current
** content of the page. However, since this content is not present in either
** the database file or the portion of the rollback journal and 
** sub-journal rolled back the content could not be restored and the
** database image would become corrupt. It is therefore fortunate that 
** this circumstance cannot arise.
*/
#if defined(SQLITE_DEBUG)

**    by finalizing the journal file. Once in WRITER_FINISHED state, it is 
**    not possible to modify the database further. At this point, the upper 
**    layer must either commit or rollback the transaction.
**
**    * A write transaction is active.
**    * An EXCLUSIVE or greater lock is held on the database file.
**    * All writing and syncing of journal and database data has finished.
**      If no error occurred, all that remains is to finalize the journal to
**      commit the transaction. If an error did occur, the caller will need
**      to rollback the transaction. 
**
**  ERROR:
**
**    The ERROR state is entered when an IO or disk-full error (including
**    SQLITE_IOERR_NOMEM) occurs at a point in the code that makes it 
................................................................................
**   The flag is cleared as soon as the journal file is finalized (either
**   by PagerCommitPhaseTwo or PagerRollback). If an IO error prevents the
**   journal file from being successfully finalized, the setMaster flag
**   is cleared anyway (and the pager will move to ERROR state).
**
** doNotSpill, doNotSyncSpill
**
**   These two boolean variables control the behavior of cache-spills
**   (calls made by the pcache module to the pagerStress() routine to
**   write cached data to the file-system in order to free up memory).
**
**   When doNotSpill is non-zero, writing to the database from pagerStress()
**   is disabled altogether. This is done in a very obscure case that
**   comes up during savepoint rollback that requires the pcache module
**   to allocate a new page to prevent the journal file from being written
................................................................................
  ){
    memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
    put32bits(&zHeader[sizeof(aJournalMagic)], 0xffffffff);
  }else{
    memset(zHeader, 0, sizeof(aJournalMagic)+4);
  }

  /* The random check-hash initializer */ 
  sqlite3_randomness(sizeof(pPager->cksumInit), &pPager->cksumInit);
  put32bits(&zHeader[sizeof(aJournalMagic)+4], pPager->cksumInit);
  /* The initial database size */
  put32bits(&zHeader[sizeof(aJournalMagic)+8], pPager->dbOrigSize);
  /* The assumed sector size for this process */
  put32bits(&zHeader[sizeof(aJournalMagic)+12], pPager->sectorSize);

................................................................................
**      be necessary to write the current content out to the sub-journal
**      (as determined by function subjRequiresPage()).
**
** If the condition asserted by this function were not true, and the
** dirty page were to be discarded from the cache via the pagerStress()
** routine, pagerStress() would not write the current page content to
** the database file. If a savepoint transaction were rolled back after
** this happened, the correct behavior would be to restore the current
** content of the page. However, since this content is not present in either
** the database file or the portion of the rollback journal and 
** sub-journal rolled back the content could not be restored and the
** database image would become corrupt. It is therefore fortunate that 
** this circumstance cannot arise.
*/
#if defined(SQLITE_DEBUG)

  assert( iDb>=0 && iDb<db->nDb );
  assert( db->aDb[iDb].pSchema );
  assert( sqlite3_mutex_held(db->mutex) );
  assert( iDb==1 || sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );

  /* zMasterSchema and zInitScript are set to point at the master schema
  ** and initialisation script appropriate for the database being
  ** initialised. zMasterName is the name of the master table.
  */
  if( !OMIT_TEMPDB && iDb==1 ){
    zMasterSchema = temp_master_schema;
  }else{
    zMasterSchema = master_schema;
  }
  zMasterName = SCHEMA_TABLE(iDb);
................................................................................
    if( DbHasProperty(db, i, DB_SchemaLoaded) || i==1 ) continue;
    rc = sqlite3InitOne(db, i, pzErrMsg);
    if( rc ){
      sqlite3ResetOneSchema(db, i);
    }
  }

  /* Once all the other databases have been initialised, load the schema
  ** for the TEMP database. This is loaded last, as the TEMP database
  ** schema may contain references to objects in other databases.
  */
#ifndef SQLITE_OMIT_TEMPDB
  if( rc==SQLITE_OK && ALWAYS(db->nDb>1)
                    && !DbHasProperty(db, 1, DB_SchemaLoaded) ){
    rc = sqlite3InitOne(db, 1, pzErrMsg);
................................................................................
    sqlite3CommitInternalChanges(db);
  }

  return rc; 
}

/*
** This routine is a no-op if the database schema is already initialised.
** Otherwise, the schema is loaded. An error code is returned.
*/
int sqlite3ReadSchema(Parse *pParse){
  int rc = SQLITE_OK;
  sqlite3 *db = pParse->db;
  assert( sqlite3_mutex_held(db->mutex) );
  if( !db->init.busy ){

  assert( iDb>=0 && iDb<db->nDb );
  assert( db->aDb[iDb].pSchema );
  assert( sqlite3_mutex_held(db->mutex) );
  assert( iDb==1 || sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );

  /* zMasterSchema and zInitScript are set to point at the master schema
  ** and initialisation script appropriate for the database being
  ** initialized. zMasterName is the name of the master table.
  */
  if( !OMIT_TEMPDB && iDb==1 ){
    zMasterSchema = temp_master_schema;
  }else{
    zMasterSchema = master_schema;
  }
  zMasterName = SCHEMA_TABLE(iDb);
................................................................................
    if( DbHasProperty(db, i, DB_SchemaLoaded) || i==1 ) continue;
    rc = sqlite3InitOne(db, i, pzErrMsg);
    if( rc ){
      sqlite3ResetOneSchema(db, i);
    }
  }

  /* Once all the other databases have been initialized, load the schema
  ** for the TEMP database. This is loaded last, as the TEMP database
  ** schema may contain references to objects in other databases.
  */
#ifndef SQLITE_OMIT_TEMPDB
  if( rc==SQLITE_OK && ALWAYS(db->nDb>1)
                    && !DbHasProperty(db, 1, DB_SchemaLoaded) ){
    rc = sqlite3InitOne(db, 1, pzErrMsg);
................................................................................
    sqlite3CommitInternalChanges(db);
  }

  return rc; 
}

/*
** This routine is a no-op if the database schema is already initialized.
** Otherwise, the schema is loaded. An error code is returned.
*/
int sqlite3ReadSchema(Parse *pParse){
  int rc = SQLITE_OK;
  sqlite3 *db = pParse->db;
  assert( sqlite3_mutex_held(db->mutex) );
  if( !db->init.busy ){

        ** If where.c is able to produce results sorted in this order, then
        ** add vdbe code to break out of the processing loop after the 
        ** first iteration (since the first iteration of the loop is 
        ** guaranteed to operate on the row with the minimum or maximum 
        ** value of x, the only row required).
        **
        ** A special flag must be passed to sqlite3WhereBegin() to slightly
        ** modify behaviour as follows:
        **
        **   + If the query is a "SELECT min(x)", then the loop coded by
        **     where.c should not iterate over any values with a NULL value
        **     for x.
        **
        **   + The optimizer code in where.c (the thing that decides which
        **     index or indices to use) should place a different priority on 

        ** If where.c is able to produce results sorted in this order, then
        ** add vdbe code to break out of the processing loop after the 
        ** first iteration (since the first iteration of the loop is 
        ** guaranteed to operate on the row with the minimum or maximum 
        ** value of x, the only row required).
        **
        ** A special flag must be passed to sqlite3WhereBegin() to slightly
        ** modify behavior as follows:
        **
        **   + If the query is a "SELECT min(x)", then the loop coded by
        **     where.c should not iterate over any values with a NULL value
        **     for x.
        **
        **   + The optimizer code in where.c (the thing that decides which
        **     index or indices to use) should place a different priority on 

**
**   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
**     "private". ^Setting it to "shared" is equivalent to setting the
**     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
**     sqlite3_open_v2(). ^Setting the cache parameter to "private" is 
**     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
**     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
**     a URI filename, its value overrides any behaviour requested by setting
**     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
** </ul>
**
** ^Specifying an unknown parameter in the query component of a URI is not an
** error.  Future versions of SQLite might understand additional query
** parameters.  See "[query parameters with special meaning to SQLite]" for
** additional information.
................................................................................
** If the requested page is already in the page cache, then the page cache
** implementation must return a pointer to the page buffer with its content
** intact.  If the requested page is not already in the cache, then the
** cache implementation should use the value of the createFlag
** parameter to help it determined what action to take:
**
** <table border=1 width=85% align=center>
** <tr><th> createFlag <th> Behaviour when page is not already in cache
** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
**                 Otherwise return NULL.
** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
**                 NULL if allocating a new page is effectively impossible.
** </table>
**

**
**   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
**     "private". ^Setting it to "shared" is equivalent to setting the
**     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
**     sqlite3_open_v2(). ^Setting the cache parameter to "private" is 
**     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
**     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
**     a URI filename, its value overrides any behavior requested by setting
**     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
** </ul>
**
** ^Specifying an unknown parameter in the query component of a URI is not an
** error.  Future versions of SQLite might understand additional query
** parameters.  See "[query parameters with special meaning to SQLite]" for
** additional information.
................................................................................
** If the requested page is already in the page cache, then the page cache
** implementation must return a pointer to the page buffer with its content
** intact.  If the requested page is not already in the cache, then the
** cache implementation should use the value of the createFlag
** parameter to help it determined what action to take:
**
** <table border=1 width=85% align=center>
** <tr><th> createFlag <th> Behavior when page is not already in cache
** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
**                 Otherwise return NULL.
** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
**                 NULL if allocating a new page is effectively impossible.
** </table>
**

  zEnd = azEnd[(rc==TCL_ERROR)*2 + (pDb->nTransaction==0)];

  pDb->disableAuth++;
  if( sqlite3_exec(pDb->db, zEnd, 0, 0, 0) ){
      /* This is a tricky scenario to handle. The most likely cause of an
      ** error is that the exec() above was an attempt to commit the 
      ** top-level transaction that returned SQLITE_BUSY. Or, less likely,
      ** that an IO-error has occured. In either case, throw a Tcl exception
      ** and try to rollback the transaction.
      **
      ** But it could also be that the user executed one or more BEGIN, 
      ** COMMIT, SAVEPOINT, RELEASE or ROLLBACK commands that are confusing
      ** this method's logic. Not clear how this would be best handled.
      */
    if( rc!=TCL_ERROR ){

  zEnd = azEnd[(rc==TCL_ERROR)*2 + (pDb->nTransaction==0)];

  pDb->disableAuth++;
  if( sqlite3_exec(pDb->db, zEnd, 0, 0, 0) ){
      /* This is a tricky scenario to handle. The most likely cause of an
      ** error is that the exec() above was an attempt to commit the 
      ** top-level transaction that returned SQLITE_BUSY. Or, less likely,
      ** that an IO-error has occurred. In either case, throw a Tcl exception
      ** and try to rollback the transaction.
      **
      ** But it could also be that the user executed one or more BEGIN, 
      ** COMMIT, SAVEPOINT, RELEASE or ROLLBACK commands that are confusing
      ** this method's logic. Not clear how this would be best handled.
      */
    if( rc!=TCL_ERROR ){

**   If the IOCAP_ATOMIC flag is set, then option (3) above is 
**   never selected.
**
**   If the IOCAP_ATOMIC512 flag is set, and the WriteBuffer represents
**   an aligned write() of an integer number of 512 byte regions, then
**   option (3) above is never selected. Instead, each 512 byte region
**   is either correctly written or left completely untouched. Similar
**   logic governs the behaviour if any of the other ATOMICXXX flags
**   is set.
**
**   If either the IOCAP_SAFEAPPEND or IOCAP_SEQUENTIAL flags are set
**   and a crash is being simulated, then an entry of the write-list is
**   selected at random. Everything in the list after the selected entry 
**   is discarded before processing begins.
**

**   If the IOCAP_ATOMIC flag is set, then option (3) above is 
**   never selected.
**
**   If the IOCAP_ATOMIC512 flag is set, and the WriteBuffer represents
**   an aligned write() of an integer number of 512 byte regions, then
**   option (3) above is never selected. Instead, each 512 byte region
**   is either correctly written or left completely untouched. Similar
**   logic governs the behavior if any of the other ATOMICXXX flags
**   is set.
**
**   If either the IOCAP_SAFEAPPEND or IOCAP_SEQUENTIAL flags are set
**   and a crash is being simulated, then an entry of the write-list is
**   selected at random. Everything in the list after the selected entry 
**   is discarded before processing begins.
**

#ifndef SQLITE_CORE
  #define SQLITE_CORE 1  /* Disable the API redefinition in sqlite3ext.h */
#endif
#include "sqlite3ext.h"

/* 
** These should be defined to be the same as the values in 
** sqliteInt.h.  They are defined seperately here so that
** the multiplex VFS shim can be built as a loadable 
** module.
*/
#define UNUSED_PARAMETER(x) (void)(x)
#define MAX_PAGE_SIZE       0x10000
#define DEFAULT_SECTOR_SIZE 0x1000

#ifndef SQLITE_CORE
  #define SQLITE_CORE 1  /* Disable the API redefinition in sqlite3ext.h */
#endif
#include "sqlite3ext.h"

/* 
** These should be defined to be the same as the values in 
** sqliteInt.h.  They are defined separately here so that
** the multiplex VFS shim can be built as a loadable 
** module.
*/
#define UNUSED_PARAMETER(x) (void)(x)
#define MAX_PAGE_SIZE       0x10000
#define DEFAULT_SECTOR_SIZE 0x1000

**
**   At runtime, logging is enabled by setting environment variable
**   SQLITE_SQLLOG_DIR to the name of a directory in which to store logged 
**   data. The directory must already exist.
**
**   Usually, if the application opens the same database file more than once
**   (either by attaching it or by using more than one database handle), only
**   a single copy is made. This behaviour may be overridden (so that a 
**   separate copy is taken each time the database file is opened or attached)
**   by setting the environment variable SQLITE_SQLLOG_REUSE_FILES to 0.
**
** OUTPUT:
**
**   The SQLITE_SQLLOG_DIR is populated with three types of files:
**

**
**   At runtime, logging is enabled by setting environment variable
**   SQLITE_SQLLOG_DIR to the name of a directory in which to store logged 
**   data. The directory must already exist.
**
**   Usually, if the application opens the same database file more than once
**   (either by attaching it or by using more than one database handle), only
**   a single copy is made. This behavior may be overridden (so that a 
**   separate copy is taken each time the database file is opened or attached)
**   by setting the environment variable SQLITE_SQLLOG_REUSE_FILES to 0.
**
** OUTPUT:
**
**   The SQLITE_SQLLOG_DIR is populated with three types of files:
**

    sqlite3VdbeAddOp2(v, OP_Affinity, regNew, pTab->nCol);
    sqlite3TableAffinityStr(v, pTab);
    sqlite3CodeRowTrigger(pParse, pTrigger, TK_UPDATE, pChanges, 
        TRIGGER_BEFORE, pTab, regOldRowid, onError, addr);

    /* The row-trigger may have deleted the row being updated. In this
    ** case, jump to the next row. No updates or AFTER triggers are 
    ** required. This behaviour - what happens when the row being updated
    ** is deleted or renamed by a BEFORE trigger - is left undefined in the
    ** documentation.
    */
    sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, regOldRowid);

    /* If it did not delete it, the row-trigger may still have modified 
    ** some of the columns of the row being updated. Load the values for 

    sqlite3VdbeAddOp2(v, OP_Affinity, regNew, pTab->nCol);
    sqlite3TableAffinityStr(v, pTab);
    sqlite3CodeRowTrigger(pParse, pTrigger, TK_UPDATE, pChanges, 
        TRIGGER_BEFORE, pTab, regOldRowid, onError, addr);

    /* The row-trigger may have deleted the row being updated. In this
    ** case, jump to the next row. No updates or AFTER triggers are 
    ** required. This behavior - what happens when the row being updated
    ** is deleted or renamed by a BEFORE trigger - is left undefined in the
    ** documentation.
    */
    sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, regOldRowid);

    /* If it did not delete it, the row-trigger may still have modified 
    ** some of the columns of the row being updated. Load the values for 

  assert(pVtab && pModule);
  rc = pModule->xOpen(pVtab, &pVtabCursor);
  importVtabErrMsg(p, pVtab);
  if( SQLITE_OK==rc ){
    /* Initialize sqlite3_vtab_cursor base class */
    pVtabCursor->pVtab = pVtab;

    /* Initialise vdbe cursor object */
    pCur = allocateCursor(p, pOp->p1, 0, -1, 0);
    if( pCur ){
      pCur->pVtabCursor = pVtabCursor;
      pCur->pModule = pVtabCursor->pVtab->pModule;
    }else{
      db->mallocFailed = 1;
      pModule->xClose(pVtabCursor);

  assert(pVtab && pModule);
  rc = pModule->xOpen(pVtab, &pVtabCursor);
  importVtabErrMsg(p, pVtab);
  if( SQLITE_OK==rc ){
    /* Initialize sqlite3_vtab_cursor base class */
    pVtabCursor->pVtab = pVtab;

    /* Initialize vdbe cursor object */
    pCur = allocateCursor(p, pOp->p1, 0, -1, 0);
    if( pCur ){
      pCur->pVtabCursor = pVtabCursor;
      pCur->pModule = pVtabCursor->pVtab->pModule;
    }else{
      db->mallocFailed = 1;
      pModule->xClose(pVtabCursor);

  */
  assert( rc==SQLITE_ROW  || rc==SQLITE_DONE   || rc==SQLITE_ERROR 
       || rc==SQLITE_BUSY || rc==SQLITE_MISUSE
  );
  assert( p->rc!=SQLITE_ROW && p->rc!=SQLITE_DONE );
  if( p->isPrepareV2 && rc!=SQLITE_ROW && rc!=SQLITE_DONE ){
    /* If this statement was prepared using sqlite3_prepare_v2(), and an
    ** error has occured, then return the error code in p->rc to the
    ** caller. Set the error code in the database handle to the same value.
    */ 
    rc = sqlite3VdbeTransferError(p);
  }
  return (rc&db->errMask);
}

  */
  assert( rc==SQLITE_ROW  || rc==SQLITE_DONE   || rc==SQLITE_ERROR 
       || rc==SQLITE_BUSY || rc==SQLITE_MISUSE
  );
  assert( p->rc!=SQLITE_ROW && p->rc!=SQLITE_DONE );
  if( p->isPrepareV2 && rc!=SQLITE_ROW && rc!=SQLITE_DONE ){
    /* If this statement was prepared using sqlite3_prepare_v2(), and an
    ** error has occurred, then return the error code in p->rc to the
    ** caller. Set the error code in the database handle to the same value.
    */ 
    rc = sqlite3VdbeTransferError(p);
  }
  return (rc&db->errMask);
}

    ){
      hasAbort = 1;
      break;
    }
  }
  sqlite3DbFree(v->db, sIter.apSub);

  /* Return true if hasAbort==mayAbort. Or if a malloc failure occured.
  ** If malloc failed, then the while() loop above may not have iterated
  ** through all opcodes and hasAbort may be set incorrectly. Return
  ** true for this case to prevent the assert() in the callers frame
  ** from failing.  */
  return ( v->db->mallocFailed || hasAbort==mayAbort );
}
#endif /* SQLITE_DEBUG - the sqlite3AssertMayAbort() function */
................................................................................
*/
int sqlite3VdbeCloseStatement(Vdbe *p, int eOp){
  sqlite3 *const db = p->db;
  int rc = SQLITE_OK;

  /* If p->iStatement is greater than zero, then this Vdbe opened a 
  ** statement transaction that should be closed here. The only exception
  ** is that an IO error may have occured, causing an emergency rollback.
  ** In this case (db->nStatement==0), and there is nothing to do.
  */
  if( db->nStatement && p->iStatement ){
    int i;
    const int iSavepoint = p->iStatement-1;

    assert( eOp==SAVEPOINT_ROLLBACK || eOp==SAVEPOINT_RELEASE);
................................................................................
      /* If the query was read-only and the error code is SQLITE_INTERRUPT, 
      ** no rollback is necessary. Otherwise, at least a savepoint 
      ** transaction must be rolled back to restore the database to a 
      ** consistent state.
      **
      ** Even if the statement is read-only, it is important to perform
      ** a statement or transaction rollback operation. If the error 
      ** occured while writing to the journal, sub-journal or database
      ** file as part of an effort to free up cache space (see function
      ** pagerStress() in pager.c), the rollback is required to restore 
      ** the pager to a consistent state.
      */
      if( !p->readOnly || mrc!=SQLITE_INTERRUPT ){
        if( (mrc==SQLITE_NOMEM || mrc==SQLITE_FULL) && p->usesStmtJournal ){
          eStatementOp = SAVEPOINT_ROLLBACK;
................................................................................
** 'serial-type' and a blob of data. The serial type is an 8-byte unsigned
** integer, stored as a varint.
**
** In an SQLite index record, the serial type is stored directly before
** the blob of data that it corresponds to. In a table record, all serial
** types are stored at the start of the record, and the blobs of data at
** the end. Hence these functions allow the caller to handle the
** serial-type and data blob seperately.
**
** The following table describes the various storage classes for data:
**
**   serial type        bytes of data      type
**   --------------     ---------------    ---------------
**      0                     0            NULL
**      1                     1            signed integer

    ){
      hasAbort = 1;
      break;
    }
  }
  sqlite3DbFree(v->db, sIter.apSub);

  /* Return true if hasAbort==mayAbort. Or if a malloc failure occurred.
  ** If malloc failed, then the while() loop above may not have iterated
  ** through all opcodes and hasAbort may be set incorrectly. Return
  ** true for this case to prevent the assert() in the callers frame
  ** from failing.  */
  return ( v->db->mallocFailed || hasAbort==mayAbort );
}
#endif /* SQLITE_DEBUG - the sqlite3AssertMayAbort() function */
................................................................................
*/
int sqlite3VdbeCloseStatement(Vdbe *p, int eOp){
  sqlite3 *const db = p->db;
  int rc = SQLITE_OK;

  /* If p->iStatement is greater than zero, then this Vdbe opened a 
  ** statement transaction that should be closed here. The only exception
  ** is that an IO error may have occurred, causing an emergency rollback.
  ** In this case (db->nStatement==0), and there is nothing to do.
  */
  if( db->nStatement && p->iStatement ){
    int i;
    const int iSavepoint = p->iStatement-1;

    assert( eOp==SAVEPOINT_ROLLBACK || eOp==SAVEPOINT_RELEASE);
................................................................................
      /* If the query was read-only and the error code is SQLITE_INTERRUPT, 
      ** no rollback is necessary. Otherwise, at least a savepoint 
      ** transaction must be rolled back to restore the database to a 
      ** consistent state.
      **
      ** Even if the statement is read-only, it is important to perform
      ** a statement or transaction rollback operation. If the error 
      ** occurred while writing to the journal, sub-journal or database
      ** file as part of an effort to free up cache space (see function
      ** pagerStress() in pager.c), the rollback is required to restore 
      ** the pager to a consistent state.
      */
      if( !p->readOnly || mrc!=SQLITE_INTERRUPT ){
        if( (mrc==SQLITE_NOMEM || mrc==SQLITE_FULL) && p->usesStmtJournal ){
          eStatementOp = SAVEPOINT_ROLLBACK;
................................................................................
** 'serial-type' and a blob of data. The serial type is an 8-byte unsigned
** integer, stored as a varint.
**
** In an SQLite index record, the serial type is stored directly before
** the blob of data that it corresponds to. In a table record, all serial
** types are stored at the start of the record, and the blobs of data at
** the end. Hence these functions allow the caller to handle the
** serial-type and data blob separately.
**
** The following table describes the various storage classes for data:
**
**   serial type        bytes of data      type
**   --------------     ---------------    ---------------
**      0                     0            NULL
**      1                     1            signed integer

*/
#define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;}

/*
** Commute a comparison operator.  Expressions of the form "X op Y"
** are converted into "Y op X".
**
** If left/right precendence rules come into play when determining the
** collating
** side of the comparison, it remains associated with the same side after
** the commutation. So "Y collate NOCASE op X" becomes 
** "X op Y". This is because any collation sequence on
** the left hand side of a comparison overrides any collation sequence 
** attached to the right. For the same reason the EP_Collate flag
** is not commuted.
................................................................................
    wsFlagMask = ~(WHERE_ROWID_EQ|WHERE_ROWID_RANGE);
    eqTermMask = idxEqTermMask;
  }

  /* If there is no ORDER BY clause and the SQLITE_ReverseOrder flag
  ** is set, then reverse the order that the index will be scanned
  ** in. This is used for application testing, to help find cases
  ** where application behaviour depends on the (undefined) order that
  ** SQLite outputs rows in in the absence of an ORDER BY clause.  */
  if( !p->pOrderBy && pParse->db->flags & SQLITE_ReverseOrder ){
    p->cost.plan.wsFlags |= WHERE_REVERSE;
  }

  assert( p->pOrderBy || (p->cost.plan.wsFlags&WHERE_ORDERED)==0 );
  assert( p->cost.plan.u.pIdx==0 || (p->cost.plan.wsFlags&WHERE_ROWID_EQ)==0 );

*/
#define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;}

/*
** Commute a comparison operator.  Expressions of the form "X op Y"
** are converted into "Y op X".
**
** If left/right precedence rules come into play when determining the
** collating
** side of the comparison, it remains associated with the same side after
** the commutation. So "Y collate NOCASE op X" becomes 
** "X op Y". This is because any collation sequence on
** the left hand side of a comparison overrides any collation sequence 
** attached to the right. For the same reason the EP_Collate flag
** is not commuted.
................................................................................
    wsFlagMask = ~(WHERE_ROWID_EQ|WHERE_ROWID_RANGE);
    eqTermMask = idxEqTermMask;
  }

  /* If there is no ORDER BY clause and the SQLITE_ReverseOrder flag
  ** is set, then reverse the order that the index will be scanned
  ** in. This is used for application testing, to help find cases
  ** where application behavior depends on the (undefined) order that
  ** SQLite outputs rows in in the absence of an ORDER BY clause.  */
  if( !p->pOrderBy && pParse->db->flags & SQLITE_ReverseOrder ){
    p->cost.plan.wsFlags |= WHERE_REVERSE;
  }

  assert( p->pOrderBy || (p->cost.plan.wsFlags&WHERE_ORDERED)==0 );
  assert( p->cost.plan.u.pIdx==0 || (p->cost.plan.wsFlags&WHERE_ROWID_EQ)==0 );

#        from the next call to backup_step() (in step 5 of this test
#        procedure).
#
#   5) Step the backup process to finish the backup. If an IO error is 
#      reported, then the backup process is concluded with a call to 
#      backup_finish().
#
#      Test that if an IO error occurs, or if one occured while updating
#      the backup database during step 4, then the conditions listed
#      under step 3 are all true.
#
#   6) Finish the backup process.
#
#   * If the backup succeeds (backup_finish() returns SQLITE_OK), then
#     the contents of the backup database should match that of the
................................................................................
    expr {$rc eq "SQLITE_OK"}
  } {1}

  # Step 4: Write to the source database.
  set rc [catchsql { UPDATE t1 SET b = randstr(1000,1000) WHERE a < 50 } sdb]

  if {[lindex $rc 0] && $::sqlite_io_error_persist==0} {
    # The IO error occured while updating the source database. In this
    # case the backup should be able to continue.
    set rc [B step 5000]
    if { $rc != "SQLITE_IOERR_UNLOCK" } {
      do_test backup_ioerr-$iTest.$iError.7 {
        list [B step 5000] [B finish]
      } {SQLITE_DONE SQLITE_OK}

#        from the next call to backup_step() (in step 5 of this test
#        procedure).
#
#   5) Step the backup process to finish the backup. If an IO error is 
#      reported, then the backup process is concluded with a call to 
#      backup_finish().
#
#      Test that if an IO error occurs, or if one occurred while updating
#      the backup database during step 4, then the conditions listed
#      under step 3 are all true.
#
#   6) Finish the backup process.
#
#   * If the backup succeeds (backup_finish() returns SQLITE_OK), then
#     the contents of the backup database should match that of the
................................................................................
    expr {$rc eq "SQLITE_OK"}
  } {1}

  # Step 4: Write to the source database.
  set rc [catchsql { UPDATE t1 SET b = randstr(1000,1000) WHERE a < 50 } sdb]

  if {[lindex $rc 0] && $::sqlite_io_error_persist==0} {
    # The IO error occurred while updating the source database. In this
    # case the backup should be able to continue.
    set rc [B step 5000]
    if { $rc != "SQLITE_IOERR_UNLOCK" } {
      do_test backup_ioerr-$iTest.$iError.7 {
        list [B step 5000] [B finish]
      } {SQLITE_DONE SQLITE_OK}

} {2}

# At one point, repeatedly locking and unlocking the cache was causing
# a resource leak of one page per repetition. The page wasn't actually
# leaked, but would not be reused until the pager-cache was full (i.e. 
# 2000 pages by default).
#
# This tests that once the pager-cache is initialised, it can be locked
# and unlocked repeatedly without internally allocating any new pages.
#
set cache_size [pager_cache_size db]
for {set ii 0} {$ii < 10} {incr ii} {
  do_test cache-1.3.$ii {
    execsql {SELECT * FROM abc}
    pager_cache_size db

} {2}

# At one point, repeatedly locking and unlocking the cache was causing
# a resource leak of one page per repetition. The page wasn't actually
# leaked, but would not be reused until the pager-cache was full (i.e. 
# 2000 pages by default).
#
# This tests that once the pager-cache is initialized, it can be locked
# and unlocked repeatedly without internally allocating any new pages.
#
set cache_size [pager_cache_size db]
for {set ii 0} {$ii < 10} {incr ii} {
  do_test cache-1.3.$ii {
    execsql {SELECT * FROM abc}
    pager_cache_size db

#
# These tests - collate4-1.* - check that indices are correctly
# selected or not selected to implement ORDER BY clauses when 
# user defined collation sequences are involved. 
#
# Because these tests also exercise all the different ways indices 
# can be created, they also serve to verify that indices are correctly 
# initialised with user-defined collation sequences when they are
# created.
#
# Tests named collate4-1.1.* use indices with a single column. Tests
# collate4-1.2.* use indices with two columns.
#
do_test collate4-1.1.0 {
  execsql {

#
# These tests - collate4-1.* - check that indices are correctly
# selected or not selected to implement ORDER BY clauses when 
# user defined collation sequences are involved. 
#
# Because these tests also exercise all the different ways indices 
# can be created, they also serve to verify that indices are correctly 
# initialized with user-defined collation sequences when they are
# created.
#
# Tests named collate4-1.1.* use indices with a single column. Tests
# collate4-1.2.* use indices with two columns.
#
do_test collate4-1.1.0 {
  execsql {

        #
        db eval BEGIN
        sqlite3_memdebug_fail $iFail -repeat 0
        catch {db eval { CREATE UNIQUE INDEX i1 ON t1(a); }} msg
        # puts "$n $msg ac=[sqlite3_get_autocommit db]"
      
        # If the transaction is still active (it may not be if the malloc()
        # failure occured in the OS layer), write to the database. Make sure
        # page 4 is among those written.
        #
        if {![sqlite3_get_autocommit db]} {
          db eval {
            DELETE FROM t1;  -- This will put page 4 on the free list.
            INSERT INTO t1 VALUES('111111111', '2222222222', '33333333');
            INSERT INTO t1 SELECT * FROM t1;                     -- 2

        #
        db eval BEGIN
        sqlite3_memdebug_fail $iFail -repeat 0
        catch {db eval { CREATE UNIQUE INDEX i1 ON t1(a); }} msg
        # puts "$n $msg ac=[sqlite3_get_autocommit db]"
      
        # If the transaction is still active (it may not be if the malloc()
        # failure occurred in the OS layer), write to the database. Make sure
        # page 4 is among those written.
        #
        if {![sqlite3_get_autocommit db]} {
          db eval {
            DELETE FROM t1;  -- This will put page 4 on the free list.
            INSERT INTO t1 VALUES('111111111', '2222222222', '33333333');
            INSERT INTO t1 SELECT * FROM t1;                     -- 2

  14   "INSERT INTO t2 VALUES(NULL, NULL)"           {}
}

# EVIDENCE-OF: R-61866-38053 Unless the column is an INTEGER PRIMARY KEY
# SQLite allows NULL values in a PRIMARY KEY column.
#
#     If the column is an integer primary key, attempting to insert a NULL
#     into the column triggers the auto-increment behaviour. Attempting
#     to use UPDATE to set an ipk column to a NULL value is an error.
#
do_createtable_tests 4.5.1 {
  1    "SELECT count(*) FROM t1 WHERE x IS NULL"                   3
  2    "SELECT count(*) FROM t2 WHERE x IS NULL"                   6
  3    "SELECT count(*) FROM t2 WHERE y IS NULL"                   7
  4    "SELECT count(*) FROM t2 WHERE x IS NULL AND y IS NULL"     2

  14   "INSERT INTO t2 VALUES(NULL, NULL)"           {}
}

# EVIDENCE-OF: R-61866-38053 Unless the column is an INTEGER PRIMARY KEY
# SQLite allows NULL values in a PRIMARY KEY column.
#
#     If the column is an integer primary key, attempting to insert a NULL
#     into the column triggers the auto-increment behavior. Attempting
#     to use UPDATE to set an ipk column to a NULL value is an error.
#
do_createtable_tests 4.5.1 {
  1    "SELECT count(*) FROM t1 WHERE x IS NULL"                   3
  2    "SELECT count(*) FROM t2 WHERE x IS NULL"                   6
  3    "SELECT count(*) FROM t2 WHERE y IS NULL"                   7
  4    "SELECT count(*) FROM t2 WHERE x IS NULL AND y IS NULL"     2

} {1 {foreign key mismatch - "c2" referencing "p"}}
do_test e_fkey-60.6 {
  execsql { DROP TABLE c2 }
  execsql { DELETE FROM p }
} {}

#-------------------------------------------------------------------------
# Test that the special behaviours of ALTER and DROP TABLE are only
# activated when foreign keys are enabled. Special behaviours are:
#
#   1. ADD COLUMN not allowing a REFERENCES clause with a non-NULL 
#      default value.
#   2. Modifying foreign key definitions when a parent table is RENAMEd.
#   3. Running an implicit DELETE FROM command as part of DROP TABLE.
#
# EVIDENCE-OF: R-54142-41346 The properties of the DROP TABLE and ALTER
................................................................................
      CREATE TABLE p(a, b, c, PRIMARY KEY(b, c));
      CREATE TABLE c(d, e, f, FOREIGN KEY(e, f) REFERENCES p MATCH $zMatch);
    "
  } {}
  do_test e_fkey-62.$zMatch.2 {
    execsql { INSERT INTO p VALUES(1, 2, 3)         }

    # MATCH SIMPLE behaviour: Allow any child key that contains one or more
    # NULL value to be inserted. Non-NULL values do not have to map to any
    # parent key values, so long as at least one field of the child key is
    # NULL.
    execsql { INSERT INTO c VALUES('w', 2, 3)       }
    execsql { INSERT INTO c VALUES('x', 'x', NULL)  }
    execsql { INSERT INTO c VALUES('y', NULL, 'x')  }
    execsql { INSERT INTO c VALUES('z', NULL, NULL) }

} {1 {foreign key mismatch - "c2" referencing "p"}}
do_test e_fkey-60.6 {
  execsql { DROP TABLE c2 }
  execsql { DELETE FROM p }
} {}

#-------------------------------------------------------------------------
# Test that the special behaviors of ALTER and DROP TABLE are only
# activated when foreign keys are enabled. Special behaviors are:
#
#   1. ADD COLUMN not allowing a REFERENCES clause with a non-NULL 
#      default value.
#   2. Modifying foreign key definitions when a parent table is RENAMEd.
#   3. Running an implicit DELETE FROM command as part of DROP TABLE.
#
# EVIDENCE-OF: R-54142-41346 The properties of the DROP TABLE and ALTER
................................................................................
      CREATE TABLE p(a, b, c, PRIMARY KEY(b, c));
      CREATE TABLE c(d, e, f, FOREIGN KEY(e, f) REFERENCES p MATCH $zMatch);
    "
  } {}
  do_test e_fkey-62.$zMatch.2 {
    execsql { INSERT INTO p VALUES(1, 2, 3)         }

    # MATCH SIMPLE behavior: Allow any child key that contains one or more
    # NULL value to be inserted. Non-NULL values do not have to map to any
    # parent key values, so long as at least one field of the child key is
    # NULL.
    execsql { INSERT INTO c VALUES('w', 2, 3)       }
    execsql { INSERT INTO c VALUES('x', 'x', NULL)  }
    execsql { INSERT INTO c VALUES('y', NULL, 'x')  }
    execsql { INSERT INTO c VALUES('z', NULL, NULL) }

  2   "SELECT DISTINCT a FROM h1" {1 4}
}

# EVIDENCE-OF: R-08861-34280 If the simple SELECT is a SELECT ALL, then
# the entire set of result rows are returned by the SELECT.
#
# EVIDENCE-OF: R-47911-02086 If neither ALL or DISTINCT are present,
# then the behaviour is as if ALL were specified.
#
# EVIDENCE-OF: R-14442-41305 If the simple SELECT is a SELECT DISTINCT,
# then duplicate rows are removed from the set of result rows before it
# is returned.
#
#   The three testable statements above are tested by e_select-5.2.*,
#   5.3.* and 5.4.* respectively.

  2   "SELECT DISTINCT a FROM h1" {1 4}
}

# EVIDENCE-OF: R-08861-34280 If the simple SELECT is a SELECT ALL, then
# the entire set of result rows are returned by the SELECT.
#
# EVIDENCE-OF: R-47911-02086 If neither ALL or DISTINCT are present,
# then the behavior is as if ALL were specified.
#
# EVIDENCE-OF: R-14442-41305 If the simple SELECT is a SELECT DISTINCT,
# then duplicate rows are removed from the set of result rows before it
# is returned.
#
#   The three testable statements above are tested by e_select-5.2.*,
#   5.3.* and 5.4.* respectively.

# to sqlite3_open_v2().
#
# EVIDENCE-OF: R-49793-28525 Setting the cache parameter to "private" is
# equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
#
# EVIDENCE-OF: R-19510-48080 If sqlite3_open_v2() is used and the
# "cache" parameter is present in a URI filename, its value overrides
# any behaviour requested by setting SQLITE_OPEN_PRIVATECACHE or
# SQLITE_OPEN_SHAREDCACHE flag.
#
set orig [sqlite3_enable_shared_cache]
foreach {tn uri flags shared_default isshared} {
  1.1   "file:test.db"                  ""         0    0
  1.2   "file:test.db"                  ""         1    1
  1.3   "file:test.db"                  private    0    0

# to sqlite3_open_v2().
#
# EVIDENCE-OF: R-49793-28525 Setting the cache parameter to "private" is
# equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
#
# EVIDENCE-OF: R-19510-48080 If sqlite3_open_v2() is used and the
# "cache" parameter is present in a URI filename, its value overrides
# any behavior requested by setting SQLITE_OPEN_PRIVATECACHE or
# SQLITE_OPEN_SHAREDCACHE flag.
#
set orig [sqlite3_enable_shared_cache]
foreach {tn uri flags shared_default isshared} {
  1.1   "file:test.db"                  ""         0    0
  1.2   "file:test.db"                  ""         1    1
  1.3   "file:test.db"                  private    0    0

# The rough organisation of tests in this file is:
#
# enc2.1.*: Simple tests with a UTF-8 db.
# enc2.2.*: Simple tests with a UTF-16LE db.
# enc2.3.*: Simple tests with a UTF-16BE db.
# enc2.4.*: Test that attached databases must have the same text encoding
#           as the main database.
# enc2.5.*: Test the behaviour of the library when a collation sequence is
#           not available for the most desirable text encoding.
# enc2.6.*: Similar test for user functions.
# enc2.7.*: Test that the VerifyCookie opcode protects against assuming the
#           wrong text encoding for the database.
# enc2.8.*: Test sqlite3_complete16()
#

# The rough organisation of tests in this file is:
#
# enc2.1.*: Simple tests with a UTF-8 db.
# enc2.2.*: Simple tests with a UTF-16LE db.
# enc2.3.*: Simple tests with a UTF-16BE db.
# enc2.4.*: Test that attached databases must have the same text encoding
#           as the main database.
# enc2.5.*: Test the behavior of the library when a collation sequence is
#           not available for the most desirable text encoding.
# enc2.6.*: Similar test for user functions.
# enc2.7.*: Test that the VerifyCookie opcode protects against assuming the
#           wrong text encoding for the database.
# enc2.8.*: Test sqlite3_complete16()
#

    }
  } {a different invocation}
  db2 close
}
sqlite3_soft_heap_limit $cmdlinearg(soft-heap-limit)

#-----------------------------------------------------------------------
# The following tests verify the behaviour of the incremental IO
# APIs in the following cases:
#
#     7.1 A row that containing an open blob is modified.
#
#     7.2 A CREATE TABLE requires that an overflow page that is part
#         of an open blob is moved.
#
#     7.3 An INCREMENTAL VACUUM moves an overflow page that is part
#         of an open blob.
#
# In the first case above, correct behaviour is for all subsequent
# read/write operations on the blob-handle to return SQLITE_ABORT.
# More accurately, blob-handles are invalidated whenever the table
# they belong to is written to.
#
# The second two cases have no external effect. They are testing
# that the internal cache of overflow page numbers is correctly
# invalidated.

    }
  } {a different invocation}
  db2 close
}
sqlite3_soft_heap_limit $cmdlinearg(soft-heap-limit)

#-----------------------------------------------------------------------
# The following tests verify the behavior of the incremental IO
# APIs in the following cases:
#
#     7.1 A row that containing an open blob is modified.
#
#     7.2 A CREATE TABLE requires that an overflow page that is part
#         of an open blob is moved.
#
#     7.3 An INCREMENTAL VACUUM moves an overflow page that is part
#         of an open blob.
#
# In the first case above, correct behavior is for all subsequent
# read/write operations on the blob-handle to return SQLITE_ABORT.
# More accurately, blob-handles are invalidated whenever the table
# they belong to is written to.
#
# The second two cases have no external effect. They are testing
# that the internal cache of overflow page numbers is correctly
# invalidated.

# Internally, this case is handled differently to the one above. The
# journal file is not actually created until the 'COMMIT' statement
# is executed.
#
# Changed 2010-03-27:  The size of the database is now stored in 
# bytes 28..31 and so when a page is added to the database, page 1
# is immediately modified and the journal file immediately comes into
# existance.  To fix this test, the BEGIN is changed into a a
# BEGIN IMMEDIATE and the INSERT is omitted.
#
do_test io-2.6.1 {
  execsql {
    BEGIN IMMEDIATE;
    -- INSERT INTO abc VALUES(9, randstr(1000,1000));
  }

# Internally, this case is handled differently to the one above. The
# journal file is not actually created until the 'COMMIT' statement
# is executed.
#
# Changed 2010-03-27:  The size of the database is now stored in 
# bytes 28..31 and so when a page is added to the database, page 1
# is immediately modified and the journal file immediately comes into
# existence.  To fix this test, the BEGIN is changed into a a
# BEGIN IMMEDIATE and the INSERT is omitted.
#
do_test io-2.6.1 {
  execsql {
    BEGIN IMMEDIATE;
    -- INSERT INTO abc VALUES(9, randstr(1000,1000));
  }

  CREATE TABLE t1(a, b);
  INSERT INTO t1 VALUES(1, 2);
  INSERT INTO t1 VALUES(3, 4);
} -sqlbody {
  SELECT test_agg_errmsg16(), group_concat(a) FROM t1
}

# At one point, if an OOM occured immediately after obtaining a shared lock
# on the database file, the file remained locked. This test case ensures
# that bug has been fixed.i
if {[db eval {PRAGMA locking_mode}]!="exclusive"} {
  do_malloc_test 37 -tclprep {
    sqlite3 db2 test.db
    execsql {
      CREATE TABLE t1(a, b);

  CREATE TABLE t1(a, b);
  INSERT INTO t1 VALUES(1, 2);
  INSERT INTO t1 VALUES(3, 4);
} -sqlbody {
  SELECT test_agg_errmsg16(), group_concat(a) FROM t1
}

# At one point, if an OOM occurred immediately after obtaining a shared lock
# on the database file, the file remained locked. This test case ensures
# that bug has been fixed.i
if {[db eval {PRAGMA locking_mode}]!="exclusive"} {
  do_malloc_test 37 -tclprep {
    sqlite3 db2 test.db
    execsql {
      CREATE TABLE t1(a, b);

        set ac [sqlite3_get_autocommit $::DB]        ;# Auto-Commit
        sqlite3_memdebug_fail $iFail -repeat 0
        set rc [catch {db eval [lindex $v 2]} msg]   ;# True error occurs
        set nac [sqlite3_get_autocommit $::DB]       ;# New Auto-Commit 

        if {$rc != 0 && $nac && !$ac} {
          # Before [db eval] the auto-commit flag was clear. Now it
          # is set. Since an error occured we assume this was not a
          # commit - therefore a rollback occured. Check that the
          # rollback-hook was invoked.
          do_test malloc3-rollback_hook_count.$iterid {
            set ::rollback_hook_count
          } {1}
        }

        set nFail [sqlite3_memdebug_fail -1 -benigncnt nBenign]

        set ac [sqlite3_get_autocommit $::DB]        ;# Auto-Commit
        sqlite3_memdebug_fail $iFail -repeat 0
        set rc [catch {db eval [lindex $v 2]} msg]   ;# True error occurs
        set nac [sqlite3_get_autocommit $::DB]       ;# New Auto-Commit 

        if {$rc != 0 && $nac && !$ac} {
          # Before [db eval] the auto-commit flag was clear. Now it
          # is set. Since an error occurred we assume this was not a
          # commit - therefore a rollback occurred. Check that the
          # rollback-hook was invoked.
          do_test malloc3-rollback_hook_count.$iterid {
            set ::rollback_hook_count
          } {1}
        }

        set nFail [sqlite3_memdebug_fail -1 -benigncnt nBenign]

        sqlite3_close $::DB
        opendb
      } 
    } elseif {$rc} {
      # Hit some other kind of error. This is a malfunction.
      error $msg
    } else {
      # No error occured. Check that any SELECT statements in the transaction
      # returned "1". Otherwise, the invariant was false, indicating that
      # some malfunction has occured.
      foreach r $msg { if {$r != 1} { puts "Invariant check failed: $msg" } }
    }
  }

  # Close the database connection and return 0.
  #
  sqlite3_close $::DB

        sqlite3_close $::DB
        opendb
      } 
    } elseif {$rc} {
      # Hit some other kind of error. This is a malfunction.
      error $msg
    } else {
      # No error occurred. Check that any SELECT statements in the transaction
      # returned "1". Otherwise, the invariant was false, indicating that
      # some malfunction has occurred.
      foreach r $msg { if {$r != 1} { puts "Invariant check failed: $msg" } }
    }
  }

  # Close the database connection and return 0.
  #
  sqlite3_close $::DB

#------------------------------------------------------------------
# These tests - subquery-4.* - use the TCL statement cache to try 
# and expose bugs to do with re-using statements that have been 
# passed to sqlite3_reset().
#
# One problem was that VDBE memory cells were not being initialised
# to NULL on the second and subsequent executions.
#
do_test subquery-4.1.1 {
  execsql {
    SELECT (SELECT a FROM t1);
  }
} {1}

#------------------------------------------------------------------
# These tests - subquery-4.* - use the TCL statement cache to try 
# and expose bugs to do with re-using statements that have been 
# passed to sqlite3_reset().
#
# One problem was that VDBE memory cells were not being initialized
# to NULL on the second and subsequent executions.
#
do_test subquery-4.1.1 {
  execsql {
    SELECT (SELECT a FROM t1);
  }
} {1}

  }
  catchsql {DROP INDEX i2}
} {1 {no such index: i2}}

# Check for correct name collision processing. A name collision can
# occur when process A creates a temporary table T then process B
# creates a permanent table also named T.  The temp table in process A
# hides the existance of the permanent table.
#
do_test temptable-4.1 {
  execsql {
    CREATE TEMP TABLE t2(x,y);
    INSERT INTO t2 VALUES(10,20);
    SELECT * FROM t2;
  } db2

  }
  catchsql {DROP INDEX i2}
} {1 {no such index: i2}}

# Check for correct name collision processing. A name collision can
# occur when process A creates a temporary table T then process B
# creates a permanent table also named T.  The temp table in process A
# hides the existence of the permanent table.
#
do_test temptable-4.1 {
  execsql {
    CREATE TEMP TABLE t2(x,y);
    INSERT INTO t2 VALUES(10,20);
    SELECT * FROM t2;
  } db2

      if {[info exists ::G(perm:dbconfig)]} {
        set ::dbhandle [lindex $args 0]
        uplevel #0 $::G(perm:dbconfig)
      }
      set res
    } else {
      # This command is not opening a new database connection. Pass the 
      # arguments through to the C implemenation as the are.
      #
      uplevel 1 sqlite_orig $args
    }
  }
}

proc getFileRetries {} {
................................................................................
# written into the files on disk. Argument $crashdelay indicates the
# number of file syncs to wait before crashing.
#
# The return value is a list of two elements. The first element is a
# boolean, indicating whether or not the process actually crashed or
# reported some other error. The second element in the returned list is the
# error message. This is "child process exited abnormally" if the crash
# occured.
#
#   crashsql -delay CRASHDELAY -file CRASHFILE ?-blocksize BLOCKSIZE? $sql
#
proc crashsql {args} {

  set blocksize ""
  set crashdelay 1
................................................................................
          array set stats [btree_pager_stats $bt]
          db_leave db
          set stats(state)
        } 0
      }
    }

    # If an IO error occured, then the checksum of the database should
    # be the same as before the script that caused the IO error was run.
    #
    if {$::go && $::sqlite_io_error_hardhit && $::ioerropts(-cksum)} {
      do_test $testname.$n.6 {
        catch {db close}
        catch {db2 close}
        set ::DB [sqlite3 db test.db; sqlite3_connection_pointer db]

      if {[info exists ::G(perm:dbconfig)]} {
        set ::dbhandle [lindex $args 0]
        uplevel #0 $::G(perm:dbconfig)
      }
      set res
    } else {
      # This command is not opening a new database connection. Pass the 
      # arguments through to the C implementation as the are.
      #
      uplevel 1 sqlite_orig $args
    }
  }
}

proc getFileRetries {} {
................................................................................
# written into the files on disk. Argument $crashdelay indicates the
# number of file syncs to wait before crashing.
#
# The return value is a list of two elements. The first element is a
# boolean, indicating whether or not the process actually crashed or
# reported some other error. The second element in the returned list is the
# error message. This is "child process exited abnormally" if the crash
# occurred.
#
#   crashsql -delay CRASHDELAY -file CRASHFILE ?-blocksize BLOCKSIZE? $sql
#
proc crashsql {args} {

  set blocksize ""
  set crashdelay 1
................................................................................
          array set stats [btree_pager_stats $bt]
          db_leave db
          set stats(state)
        } 0
      }
    }

    # If an IO error occurred, then the checksum of the database should
    # be the same as before the script that caused the IO error was run.
    #
    if {$::go && $::sqlite_io_error_hardhit && $::ioerropts(-cksum)} {
      do_test $testname.$n.6 {
        catch {db close}
        catch {db2 close}
        set ::DB [sqlite3 db test.db; sqlite3_connection_pointer db]

} {SQLITE_OK}

# Check the integrity of the cache.
#
integrity_check tkt2409-1.3

# Check that the transaction was rolled back. Because the INSERT
# statement in which the "I/O error" occured did not open a statement
# transaction, SQLite had no choice but to roll back the transaction.
#
do_test tkt2409-1.4 {
  unread_lock_db
  catchsql { ROLLBACK }
} {0 {}}

................................................................................
} {SQLITE_OK}

# Check the integrity of the cache.
#
integrity_check tkt2409-3.3

# Check that the transaction was rolled back. Because the INSERT
# statement in which the "I/O error" occured did not open a statement
# transaction, SQLite had no choice but to roll back the transaction.
#
do_test tkt2409-3.4 {
  unread_lock_db
  catchsql { ROLLBACK }
} {0 {}}
integrity_check tkt2409-3.5

} {SQLITE_OK}

# Check the integrity of the cache.
#
integrity_check tkt2409-1.3

# Check that the transaction was rolled back. Because the INSERT
# statement in which the "I/O error" occurred did not open a statement
# transaction, SQLite had no choice but to roll back the transaction.
#
do_test tkt2409-1.4 {
  unread_lock_db
  catchsql { ROLLBACK }
} {0 {}}

................................................................................
} {SQLITE_OK}

# Check the integrity of the cache.
#
integrity_check tkt2409-3.3

# Check that the transaction was rolled back. Because the INSERT
# statement in which the "I/O error" occurred did not open a statement
# transaction, SQLite had no choice but to roll back the transaction.
#
do_test tkt2409-3.4 {
  unread_lock_db
  catchsql { ROLLBACK }
} {0 {}}
integrity_check tkt2409-3.5