main.c

sqlite数据库管理系统开放源码

  assert( (db->flags & SQLITE_Initialized)==0 );
  rc = SQLITE_OK;
  db->init.busy = 1;
  for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
    if( DbHasProperty(db, i, DB_SchemaLoaded) || i==1 ) continue;
    rc = sqliteInitOne(db, i, pzErrMsg);
    if( rc ){
      sqliteResetInternalSchema(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.
  */
  if( rc==SQLITE_OK && db->nDb>1 && !DbHasProperty(db, 1, DB_SchemaLoaded) ){
    rc = sqliteInitOne(db, 1, pzErrMsg);
    if( rc ){
      sqliteResetInternalSchema(db, 1);
    }
  }

  db->init.busy = 0;
  if( rc==SQLITE_OK ){
    db->flags |= SQLITE_Initialized;
    sqliteCommitInternalChanges(db);
  }

  /* If the database is in formats 1 or 2, then upgrade it to
  ** version 3.  This will reconstruct all indices.  If the
  ** upgrade fails for any reason (ex: out of disk space, database
  ** is read only, interrupt received, etc.) then fail the init.
  */
  if( rc==SQLITE_OK && db->file_format<3 ){
    char *zErr = 0;
    InitData initData;
    int meta[SQLITE_N_BTREE_META];

    db->magic = SQLITE_MAGIC_OPEN;
    initData.db = db;
    initData.pzErrMsg = &zErr;
    db->file_format = 3;
    rc = sqlite_exec(db,
      "BEGIN; SELECT name FROM sqlite_master WHERE type='table';",
      upgrade_3_callback,
      &initData,
      &zErr);
    if( rc==SQLITE_OK ){
      sqliteBtreeGetMeta(db->aDb[0].pBt, meta);
      meta[2] = 4;
      sqliteBtreeUpdateMeta(db->aDb[0].pBt, meta);
      sqlite_exec(db, "COMMIT", 0, 0, 0);
    }
    if( rc!=SQLITE_OK ){
      sqliteSetString(pzErrMsg, 
        "unable to upgrade database to the version 2.6 format",
        zErr ? ": " : 0, zErr, (char*)0);
    }
    sqlite_freemem(zErr);
  }

  if( rc!=SQLITE_OK ){
    db->flags &= ~SQLITE_Initialized;
  }
  return rc;
}

/*
** The version of the library
*/
const char rcsid[] = "@(#) \044Id: SQLite version " SQLITE_VERSION " $";
const char sqlite_version[] = SQLITE_VERSION;

/*
** Does the library expect data to be encoded as UTF-8 or iso8859?  The
** following global constant always lets us know.
*/
#ifdef SQLITE_UTF8
const char sqlite_encoding[] = "UTF-8";
#else
const char sqlite_encoding[] = "iso8859";
#endif

/*
** Open a new SQLite database.  Construct an "sqlite" structure to define
** the state of this database and return a pointer to that structure.
**
** An attempt is made to initialize the in-memory data structures that
** hold the database schema.  But if this fails (because the schema file
** is locked) then that step is deferred until the first call to
** sqlite_exec().
*/
sqlite *sqlite_open(const char *zFilename, int mode, char **pzErrMsg){
  sqlite *db;
  int rc, i;

  /* Allocate the sqlite data structure */
  db = sqliteMalloc( sizeof(sqlite) );
  if( pzErrMsg ) *pzErrMsg = 0;
  if( db==0 ) goto no_mem_on_open;
  db->onError = OE_Default;
  db->priorNewRowid = 0;
  db->magic = SQLITE_MAGIC_BUSY;
  db->nDb = 2;
  db->aDb = db->aDbStatic;
  /* db->flags |= SQLITE_ShortColNames; */
  sqliteHashInit(&db->aFunc, SQLITE_HASH_STRING, 1);
  for(i=0; i<db->nDb; i++){
    sqliteHashInit(&db->aDb[i].tblHash, SQLITE_HASH_STRING, 0);
    sqliteHashInit(&db->aDb[i].idxHash, SQLITE_HASH_STRING, 0);
    sqliteHashInit(&db->aDb[i].trigHash, SQLITE_HASH_STRING, 0);
    sqliteHashInit(&db->aDb[i].aFKey, SQLITE_HASH_STRING, 1);
  }
  
  /* Open the backend database driver */
  if( zFilename[0]==':' && strcmp(zFilename,":memory:")==0 ){
    db->temp_store = 2;
  }
  rc = sqliteBtreeFactory(db, zFilename, 0, MAX_PAGES, &db->aDb[0].pBt);
  if( rc!=SQLITE_OK ){
    switch( rc ){
      default: {
        sqliteSetString(pzErrMsg, "unable to open database: ",
           zFilename, (char*)0);
      }
    }
    sqliteFree(db);
    sqliteStrRealloc(pzErrMsg);
    return 0;
  }
  db->aDb[0].zName = "main";
  db->aDb[1].zName = "temp";

  /* Attempt to read the schema */
  sqliteRegisterBuiltinFunctions(db);
  rc = sqliteInit(db, pzErrMsg);
  db->magic = SQLITE_MAGIC_OPEN;
  if( sqlite_malloc_failed ){
    sqlite_close(db);
    goto no_mem_on_open;
  }else if( rc!=SQLITE_OK && rc!=SQLITE_BUSY ){
    sqlite_close(db);
    sqliteStrRealloc(pzErrMsg);
    return 0;
  }else if( pzErrMsg ){
    sqliteFree(*pzErrMsg);
    *pzErrMsg = 0;
  }

  /* Return a pointer to the newly opened database structure */
  return db;

no_mem_on_open:
  sqliteSetString(pzErrMsg, "out of memory", (char*)0);
  sqliteStrRealloc(pzErrMsg);
  return 0;
}

/*
** Return the ROWID of the most recent insert
*/
int sqlite_last_insert_rowid(sqlite *db){
  return db->lastRowid;
}

/*
** Return the number of changes in the most recent call to sqlite_exec().
*/
int sqlite_changes(sqlite *db){
  return db->nChange;
}

/*
** Return the number of changes produced by the last INSERT, UPDATE, or
** DELETE statement to complete execution. The count does not include
** changes due to SQL statements executed in trigger programs that were
** triggered by that statement
*/
int sqlite_last_statement_changes(sqlite *db){
  return db->lsChange;
}

/*
** Close an existing SQLite database
*/
void sqlite_close(sqlite *db){
  HashElem *i;
  int j;
  db->want_to_close = 1;
  if( sqliteSafetyCheck(db) || sqliteSafetyOn(db) ){
    /* printf("DID NOT CLOSE\n"); fflush(stdout); */
    return;
  }
  db->magic = SQLITE_MAGIC_CLOSED;
  for(j=0; j<db->nDb; j++){
    struct Db *pDb = &db->aDb[j];
    if( pDb->pBt ){
      sqliteBtreeClose(pDb->pBt);
      pDb->pBt = 0;
    }
  }
  sqliteResetInternalSchema(db, 0);
  assert( db->nDb<=2 );
  assert( db->aDb==db->aDbStatic );
  for(i=sqliteHashFirst(&db->aFunc); i; i=sqliteHashNext(i)){
    FuncDef *pFunc, *pNext;
    for(pFunc = (FuncDef*)sqliteHashData(i); pFunc; pFunc=pNext){
      pNext = pFunc->pNext;
      sqliteFree(pFunc);
    }
  }
  sqliteHashClear(&db->aFunc);
  sqliteFree(db);
}

/*
** Rollback all database files.
*/
void sqliteRollbackAll(sqlite *db){
  int i;
  for(i=0; i<db->nDb; i++){
    if( db->aDb[i].pBt ){
      sqliteBtreeRollback(db->aDb[i].pBt);
      db->aDb[i].inTrans = 0;
    }
  }
  sqliteResetInternalSchema(db, 0);
  /* sqliteRollbackInternalChanges(db); */
}

/*
** Execute SQL code.  Return one of the SQLITE_ success/failure
** codes.  Also write an error message into memory obtained from
** malloc() and make *pzErrMsg point to that message.
**
** If the SQL is a query, then for each row in the query result
** the xCallback() function is called.  pArg becomes the first
** argument to xCallback().  If xCallback=NULL then no callback
** is invoked, even for queries.
*/
int sqlite_exec(
  sqlite *db,                 /* The database on which the SQL executes */
  const char *zSql,           /* The SQL to be executed */
  sqlite_callback xCallback,  /* Invoke this callback routine */
  void *pArg,                 /* First argument to xCallback() */
  char **pzErrMsg             /* Write error messages here */
){
  int rc = SQLITE_OK;
  const char *zLeftover;
  sqlite_vm *pVm;
  int nRetry = 0;
  int nChange = 0;
  int nCallback;

  if( zSql==0 ) return SQLITE_OK;
  while( rc==SQLITE_OK && zSql[0] ){
    pVm = 0;
    rc = sqlite_compile(db, zSql, &zLeftover, &pVm, pzErrMsg);
    if( rc!=SQLITE_OK ){
      assert( pVm==0 || sqlite_malloc_failed );
      return rc;
    }
    if( pVm==0 ){
      /* This happens if the zSql input contained only whitespace */
      break;
    }
    db->nChange += nChange;
    nCallback = 0;
    while(1){
      int nArg;
      char **azArg, **azCol;
      rc = sqlite_step(pVm, &nArg, (const char***)&azArg,(const char***)&azCol);
      if( rc==SQLITE_ROW ){
        if( xCallback!=0 && xCallback(pArg, nArg, azArg, azCol) ){
          sqlite_finalize(pVm, 0);
          return SQLITE_ABORT;
        }
        nCallback++;
      }else{
        if( rc==SQLITE_DONE && nCallback==0
          && (db->flags & SQLITE_NullCallback)!=0 && xCallback!=0 ){
          xCallback(pArg, nArg, azArg, azCol);
        }
        rc = sqlite_finalize(pVm, pzErrMsg);
        if( rc==SQLITE_SCHEMA && nRetry<2 ){
          nRetry++;
          rc = SQLITE_OK;
          break;
        }
        if( db->pVdbe==0 ){
          nChange = db->nChange;
        }
        nRetry = 0;
        zSql = zLeftover;
        while( isspace(zSql[0]) ) zSql++;
        break;
      }
    }
  }
  return rc;
}


/*
** Compile a single statement of SQL into a virtual machine.  Return one
** of the SQLITE_ success/failure codes.  Also write an error message into
** memory obtained from malloc() and make *pzErrMsg point to that message.
*/
int sqlite_compile(
  sqlite *db,                 /* The database on which the SQL executes */
  const char *zSql,           /* The SQL to be executed */
  const char **pzTail,        /* OUT: Next statement after the first */
  sqlite_vm **ppVm,           /* OUT: The virtual machine */
  char **pzErrMsg             /* OUT: Write error messages here */
){
  Parse sParse;

  if( pzErrMsg ) *pzErrMsg = 0;
  if( sqliteSafetyOn(db) ) goto exec_misuse;
  if( !db->init.busy ){
    if( (db->flags & SQLITE_Initialized)==0 ){
      int rc, cnt = 1;
      while( (rc = sqliteInit(db, pzErrMsg))==SQLITE_BUSY
         && db->xBusyCallback
         && db->xBusyCallback(db->pBusyArg, "", cnt++)!=0 ){}
      if( rc!=SQLITE_OK ){
        sqliteStrRealloc(pzErrMsg);
        sqliteSafetyOff(db);
        return rc;
      }
      if( pzErrMsg ){
        sqliteFree(*pzErrMsg);
        *pzErrMsg = 0;
      }
    }
    if( db->file_format<3 ){
      sqliteSafetyOff(db);
      sqliteSetString(pzErrMsg, "obsolete database file format", (char*)0);
      return SQLITE_ERROR;
    }
  }
  assert( (db->flags & SQLITE_Initialized)!=0 || db->init.busy );
  if( db->pVdbe==0 ){ db->nChange = 0; }
  memset(&sParse, 0, sizeof(sParse));
  sParse.db = db;
  sqliteRunParser(&sParse, zSql, pzErrMsg);
  if( db->xTrace && !db->init.busy ){
    /* Trace only the statment that was compiled.
    ** Make a copy of that part of the SQL string since zSQL is const
    ** and we must pass a zero terminated string to the trace function
    ** The copy is unnecessary if the tail pointer is pointing at the
    ** beginnig or end of the SQL string.
    */
    if( sParse.zTail && sParse.zTail!=zSql && *sParse.zTail ){
      char *tmpSql = sqliteStrNDup(zSql, sParse.zTail - zSql);
      if( tmpSql ){
        db->xTrace(db->pTraceArg, tmpSql);
        free(tmpSql);
      }else{
        /* If a memory error occurred during the copy,
        ** trace entire SQL string and fall through to the
        ** sqlite_malloc_failed test to report the error.
        */
        db->xTrace(db->pTraceArg, zSql); 
      }
    }else{
      db->xTrace(db->pTraceArg, zSql); 
    }
  }
  if( sqlite_malloc_failed ){
    sqliteSetString(pzErrMsg, "out of memory", (char*)0);
    sParse.rc = SQLITE_NOMEM;
    sqliteRollbackAll(db);
    sqliteResetInternalSchema(db, 0);
    db->flags &= ~SQLITE_InTrans;
  }
  if( sParse.rc==SQLITE_DONE ) sParse.rc = SQLITE_OK;
  if( sParse.rc!=SQLITE_OK && pzErrMsg && *pzErrMsg==0 ){
    sqliteSetString(pzErrMsg, sqlite_error_string(sParse.rc), (char*)0);
  }
  sqliteStrRealloc(pzErrMsg);
  if( sParse.rc==SQLITE_SCHEMA ){