main.c

sqlite的最新源码 This ZIP archive contains preprocessed C code for the SQLite library as individual sour

/*
** Cause any pending operation to stop at its earliest opportunity.
*/
void sqlite3_interrupt(sqlite3 *db){
  db->u1.isInterrupted = 1;
}


/*
** This function is exactly the same as sqlite3_create_function(), except
** that it is designed to be called by internal code. The difference is
** that if a malloc() fails in sqlite3_create_function(), an error code
** is returned and the mallocFailed flag cleared. 
*/
int sqlite3CreateFunc(
  sqlite3 *db,
  const char *zFunctionName,
  int nArg,
  int enc,
  void *pUserData,
  void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
  void (*xStep)(sqlite3_context*,int,sqlite3_value **),
  void (*xFinal)(sqlite3_context*)
){
  FuncDef *p;
  int nName;

  assert( sqlite3_mutex_held(db->mutex) );
  if( zFunctionName==0 ||
      (xFunc && (xFinal || xStep)) || 
      (!xFunc && (xFinal && !xStep)) ||
      (!xFunc && (!xFinal && xStep)) ||
      (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG) ||
      (255<(nName = sqlite3Strlen(db, zFunctionName))) ){
    sqlite3Error(db, SQLITE_ERROR, "bad parameters");
    return SQLITE_ERROR;
  }
  
#ifndef SQLITE_OMIT_UTF16
  /* If SQLITE_UTF16 is specified as the encoding type, transform this
  ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
  ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
  **
  ** If SQLITE_ANY is specified, add three versions of the function
  ** to the hash table.
  */
  if( enc==SQLITE_UTF16 ){
    enc = SQLITE_UTF16NATIVE;
  }else if( enc==SQLITE_ANY ){
    int rc;
    rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8,
         pUserData, xFunc, xStep, xFinal);
    if( rc==SQLITE_OK ){
      rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE,
          pUserData, xFunc, xStep, xFinal);
    }
    if( rc!=SQLITE_OK ){
      return rc;
    }
    enc = SQLITE_UTF16BE;
  }
#else
  enc = SQLITE_UTF8;
#endif
  
  /* Check if an existing function is being overridden or deleted. If so,
  ** and there are active VMs, then return SQLITE_BUSY. If a function
  ** is being overridden/deleted but there are no active VMs, allow the
  ** operation to continue but invalidate all precompiled statements.
  */
  p = sqlite3FindFunction(db, zFunctionName, nName, nArg, enc, 0);
  if( p && p->iPrefEnc==enc && p->nArg==nArg ){
    if( db->activeVdbeCnt ){
      sqlite3Error(db, SQLITE_BUSY, 
        "Unable to delete/modify user-function due to active statements");
      assert( !db->mallocFailed );
      return SQLITE_BUSY;
    }else{
      sqlite3ExpirePreparedStatements(db);
    }
  }

  p = sqlite3FindFunction(db, zFunctionName, nName, nArg, enc, 1);
  assert(p || db->mallocFailed);
  if( !p ){
    return SQLITE_NOMEM;
  }
  p->flags = 0;
  p->xFunc = xFunc;
  p->xStep = xStep;
  p->xFinalize = xFinal;
  p->pUserData = pUserData;
  p->nArg = nArg;
  return SQLITE_OK;
}

/*
** Create new user functions.
*/
int sqlite3_create_function(
  sqlite3 *db,
  const char *zFunctionName,
  int nArg,
  int enc,
  void *p,
  void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
  void (*xStep)(sqlite3_context*,int,sqlite3_value **),
  void (*xFinal)(sqlite3_context*)
){
  int rc;
  sqlite3_mutex_enter(db->mutex);
  rc = sqlite3CreateFunc(db, zFunctionName, nArg, enc, p, xFunc, xStep, xFinal);
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);
  return rc;
}

#ifndef SQLITE_OMIT_UTF16
int sqlite3_create_function16(
  sqlite3 *db,
  const void *zFunctionName,
  int nArg,
  int eTextRep,
  void *p,
  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
  void (*xFinal)(sqlite3_context*)
){
  int rc;
  char *zFunc8;
  sqlite3_mutex_enter(db->mutex);
  assert( !db->mallocFailed );
  zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1);
  rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xFunc, xStep, xFinal);
  sqlite3DbFree(db, zFunc8);
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);
  return rc;
}
#endif


/*
** Declare that a function has been overloaded by a virtual table.
**
** If the function already exists as a regular global function, then
** this routine is a no-op.  If the function does not exist, then create
** a new one that always throws a run-time error.  
**
** When virtual tables intend to provide an overloaded function, they
** should call this routine to make sure the global function exists.
** A global function must exist in order for name resolution to work
** properly.
*/
int sqlite3_overload_function(
  sqlite3 *db,
  const char *zName,
  int nArg
){
  int nName = sqlite3Strlen(db, zName);
  int rc;
  sqlite3_mutex_enter(db->mutex);
  if( sqlite3FindFunction(db, zName, nName, nArg, SQLITE_UTF8, 0)==0 ){
    sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
                      0, sqlite3InvalidFunction, 0, 0);
  }
  rc = sqlite3ApiExit(db, SQLITE_OK);
  sqlite3_mutex_leave(db->mutex);
  return rc;
}

#ifndef SQLITE_OMIT_TRACE
/*
** Register a trace function.  The pArg from the previously registered trace
** is returned.  
**
** A NULL trace function means that no tracing is executes.  A non-NULL
** trace is a pointer to a function that is invoked at the start of each
** SQL statement.
*/
void *sqlite3_trace(sqlite3 *db, void (*xTrace)(void*,const char*), void *pArg){
  void *pOld;
  sqlite3_mutex_enter(db->mutex);
  pOld = db->pTraceArg;
  db->xTrace = xTrace;
  db->pTraceArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pOld;
}
/*
** Register a profile function.  The pArg from the previously registered 
** profile function is returned.  
**
** A NULL profile function means that no profiling is executes.  A non-NULL
** profile is a pointer to a function that is invoked at the conclusion of
** each SQL statement that is run.
*/
void *sqlite3_profile(
  sqlite3 *db,
  void (*xProfile)(void*,const char*,sqlite_uint64),
  void *pArg
){
  void *pOld;
  sqlite3_mutex_enter(db->mutex);
  pOld = db->pProfileArg;
  db->xProfile = xProfile;
  db->pProfileArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pOld;
}
#endif /* SQLITE_OMIT_TRACE */

/*** EXPERIMENTAL ***
**
** Register a function to be invoked when a transaction comments.
** If the invoked function returns non-zero, then the commit becomes a
** rollback.
*/
void *sqlite3_commit_hook(
  sqlite3 *db,              /* Attach the hook to this database */
  int (*xCallback)(void*),  /* Function to invoke on each commit */
  void *pArg                /* Argument to the function */
){
  void *pOld;
  sqlite3_mutex_enter(db->mutex);
  pOld = db->pCommitArg;
  db->xCommitCallback = xCallback;
  db->pCommitArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pOld;
}

/*
** Register a callback to be invoked each time a row is updated,
** inserted or deleted using this database connection.
*/
void *sqlite3_update_hook(
  sqlite3 *db,              /* Attach the hook to this database */
  void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
  void *pArg                /* Argument to the function */
){
  void *pRet;
  sqlite3_mutex_enter(db->mutex);
  pRet = db->pUpdateArg;
  db->xUpdateCallback = xCallback;
  db->pUpdateArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pRet;
}

/*
** Register a callback to be invoked each time a transaction is rolled
** back by this database connection.
*/
void *sqlite3_rollback_hook(
  sqlite3 *db,              /* Attach the hook to this database */
  void (*xCallback)(void*), /* Callback function */
  void *pArg                /* Argument to the function */
){
  void *pRet;
  sqlite3_mutex_enter(db->mutex);
  pRet = db->pRollbackArg;
  db->xRollbackCallback = xCallback;
  db->pRollbackArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pRet;
}

/*
** This routine is called to create a connection to a database BTree
** driver.  If zFilename is the name of a file, then that file is
** opened and used.  If zFilename is the magic name ":memory:" then
** the database is stored in memory (and is thus forgotten as soon as
** the connection is closed.)  If zFilename is NULL then the database
** is a "virtual" database for transient use only and is deleted as
** soon as the connection is closed.
**
** A virtual database can be either a disk file (that is automatically
** deleted when the file is closed) or it an be held entirely in memory,
** depending on the values of the SQLITE_TEMP_STORE compile-time macro and the
** db->temp_store variable, according to the following chart:
**
**   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
**   -----------------     --------------     ------------------------------
**   0                     any                file
**   1                     1                  file
**   1                     2                  memory
**   1                     0                  file
**   2                     1                  file
**   2                     2                  memory
**   2                     0                  memory
**   3                     any                memory
*/
int sqlite3BtreeFactory(
  const sqlite3 *db,        /* Main database when opening aux otherwise 0 */
  const char *zFilename,    /* Name of the file containing the BTree database */
  int omitJournal,          /* if TRUE then do not journal this file */
  int nCache,               /* How many pages in the page cache */
  int vfsFlags,             /* Flags passed through to vfsOpen */
  Btree **ppBtree           /* Pointer to new Btree object written here */
){
  int btFlags = 0;
  int rc;
  
  assert( sqlite3_mutex_held(db->mutex) );
  assert( ppBtree != 0);
  if( omitJournal ){
    btFlags |= BTREE_OMIT_JOURNAL;
  }
  if( db->flags & SQLITE_NoReadlock ){
    btFlags |= BTREE_NO_READLOCK;
  }
  if( zFilename==0 ){
#if SQLITE_TEMP_STORE==0
    /* Do nothing */
#endif
#ifndef SQLITE_OMIT_MEMORYDB
#if SQLITE_TEMP_STORE==1
    if( db->temp_store==2 ) zFilename = ":memory:";
#endif
#if SQLITE_TEMP_STORE==2
    if( db->temp_store!=1 ) zFilename = ":memory:";
#endif
#if SQLITE_TEMP_STORE==3
    zFilename = ":memory:";
#endif
#endif /* SQLITE_OMIT_MEMORYDB */
  }

  if( (vfsFlags & SQLITE_OPEN_MAIN_DB)!=0 && (zFilename==0 || *zFilename==0) ){
    vfsFlags = (vfsFlags & ~SQLITE_OPEN_MAIN_DB) | SQLITE_OPEN_TEMP_DB;
  }
  rc = sqlite3BtreeOpen(zFilename, (sqlite3 *)db, ppBtree, btFlags, vfsFlags);

  /* If the B-Tree was successfully opened, set the pager-cache size to the
  ** default value. Except, if the call to BtreeOpen() returned a handle
  ** open on an existing shared pager-cache, do not change the pager-cache 
  ** size.
  */
  if( rc==SQLITE_OK && 0==sqlite3BtreeSchema(*ppBtree, 0, 0) ){
    sqlite3BtreeSetCacheSize(*ppBtree, nCache);
  }
  return rc;
}

/*
** Return UTF-8 encoded English language explanation of the most recent
** error.
*/
const char *sqlite3_errmsg(sqlite3 *db){
  const char *z;
  if( !db ){
    return sqlite3ErrStr(SQLITE_NOMEM);
  }
  if( !sqlite3SafetyCheckSickOrOk(db) ){
    return sqlite3ErrStr(SQLITE_MISUSE);
  }
  sqlite3_mutex_enter(db->mutex);
  assert( !db->mallocFailed );
  z = (char*)sqlite3_value_text(db->pErr);
  assert( !db->mallocFailed );
  if( z==0 ){
    z = sqlite3ErrStr(db->errCode);
  }
  sqlite3_mutex_leave(db->mutex);
  return z;
}

#ifndef SQLITE_OMIT_UTF16
/*
** Return UTF-16 encoded English language explanation of the most recent
** error.
*/
const void *sqlite3_errmsg16(sqlite3 *db){
  /* Because all the characters in the string are in the unicode
  ** range 0x00-0xFF, if we pad the big-endian string with a 
  ** zero byte, we can obtain the little-endian string with
  ** &big_endian[1].
  */
  static const char outOfMemBe[] = {
    0, 'o', 0, 'u', 0, 't', 0, ' ', 
    0, 'o', 0, 'f', 0, ' ', 
    0, 'm', 0, 'e', 0, 'm', 0, 'o', 0, 'r', 0, 'y', 0, 0, 0
  };
  static const char misuseBe [] = {
    0, 'l', 0, 'i', 0, 'b', 0, 'r', 0, 'a', 0, 'r', 0, 'y', 0, ' ', 
    0, 'r', 0, 'o', 0, 'u', 0, 't', 0, 'i', 0, 'n', 0, 'e', 0, ' ', 
    0, 'c', 0, 'a', 0, 'l', 0, 'l', 0, 'e', 0, 'd', 0, ' ', 
    0, 'o', 0, 'u', 0, 't', 0, ' ', 
    0, 'o', 0, 'f', 0, ' ', 
    0, 's', 0, 'e', 0, 'q', 0, 'u', 0, 'e', 0, 'n', 0, 'c', 0, 'e', 0, 0, 0
  };

  const void *z;
  if( !db ){
    return (void *)(&outOfMemBe[SQLITE_UTF16NATIVE==SQLITE_UTF16LE?1:0]);
  }
  if( !sqlite3SafetyCheckSickOrOk(db) ){
    return (void *)(&misuseBe[SQLITE_UTF16NATIVE==SQLITE_UTF16LE?1:0]);
  }
  sqlite3_mutex_enter(db->mutex);
  assert( !db->mallocFailed );
  z = sqlite3_value_text16(db->pErr);
  if( z==0 ){
    sqlite3ValueSetStr(db->pErr, -1, sqlite3ErrStr(db->errCode),
         SQLITE_UTF8, SQLITE_STATIC);
    z = sqlite3_value_text16(db->pErr);
  }
  /* A malloc() may have failed within the call to sqlite3_value_text16()
  ** above. If this is the case, then the db->mallocFailed flag needs to
  ** be cleared before returning. Do this directly, instead of via
  ** sqlite3ApiExit(), to avoid setting the database handle error message.
  */
  db->mallocFailed = 0;
  sqlite3_mutex_leave(db->mutex);
  return z;
}
#endif /* SQLITE_OMIT_UTF16 */

/*
** Return the most recent error code generated by an SQLite routine. If NULL is
** passed to this function, we assume a malloc() failed during sqlite3_open().
*/
int sqlite3_errcode(sqlite3 *db){
  if( db && !sqlite3SafetyCheckSickOrOk(db) ){