main.c

sqlite数据库管理系统开放源码

    sqliteResetInternalSchema(db, 0);
  }
  assert( ppVm );
  *ppVm = (sqlite_vm*)sParse.pVdbe;
  if( pzTail ) *pzTail = sParse.zTail;
  if( sqliteSafetyOff(db) ) goto exec_misuse;
  return sParse.rc;

exec_misuse:
  if( pzErrMsg ){
    *pzErrMsg = 0;
    sqliteSetString(pzErrMsg, sqlite_error_string(SQLITE_MISUSE), (char*)0);
    sqliteStrRealloc(pzErrMsg);
  }
  return SQLITE_MISUSE;
}


/*
** The following routine destroys a virtual machine that is created by
** the sqlite_compile() routine.
**
** The integer returned is an SQLITE_ success/failure code that describes
** the result of executing the virtual machine.  An error message is
** written into memory obtained from malloc and *pzErrMsg is made to
** point to that error if pzErrMsg is not NULL.  The calling routine
** should use sqlite_freemem() to delete the message when it has finished
** with it.
*/
int sqlite_finalize(
  sqlite_vm *pVm,            /* The virtual machine to be destroyed */
  char **pzErrMsg            /* OUT: Write error messages here */
){
  int rc = sqliteVdbeFinalize((Vdbe*)pVm, pzErrMsg);
  sqliteStrRealloc(pzErrMsg);
  return rc;
}

/*
** Terminate the current execution of a virtual machine then
** reset the virtual machine back to its starting state so that it
** can be reused.  Any error message resulting from the prior execution
** is written into *pzErrMsg.  A success code from the prior execution
** is returned.
*/
int sqlite_reset(
  sqlite_vm *pVm,            /* The virtual machine to be destroyed */
  char **pzErrMsg            /* OUT: Write error messages here */
){
  int rc = sqliteVdbeReset((Vdbe*)pVm, pzErrMsg);
  sqliteVdbeMakeReady((Vdbe*)pVm, -1, 0);
  sqliteStrRealloc(pzErrMsg);
  return rc;
}

/*
** Return a static string that describes the kind of error specified in the
** argument.
*/
const char *sqlite_error_string(int rc){
  const char *z;
  switch( rc ){
    case SQLITE_OK:         z = "not an error";                          break;
    case SQLITE_ERROR:      z = "SQL logic error or missing database";   break;
    case SQLITE_INTERNAL:   z = "internal SQLite implementation flaw";   break;
    case SQLITE_PERM:       z = "access permission denied";              break;
    case SQLITE_ABORT:      z = "callback requested query abort";        break;
    case SQLITE_BUSY:       z = "database is locked";                    break;
    case SQLITE_LOCKED:     z = "database table is locked";              break;
    case SQLITE_NOMEM:      z = "out of memory";                         break;
    case SQLITE_READONLY:   z = "attempt to write a readonly database";  break;
    case SQLITE_INTERRUPT:  z = "interrupted";                           break;
    case SQLITE_IOERR:      z = "disk I/O error";                        break;
    case SQLITE_CORRUPT:    z = "database disk image is malformed";      break;
    case SQLITE_NOTFOUND:   z = "table or record not found";             break;
    case SQLITE_FULL:       z = "database is full";                      break;
    case SQLITE_CANTOPEN:   z = "unable to open database file";          break;
    case SQLITE_PROTOCOL:   z = "database locking protocol failure";     break;
    case SQLITE_EMPTY:      z = "table contains no data";                break;
    case SQLITE_SCHEMA:     z = "database schema has changed";           break;
    case SQLITE_TOOBIG:     z = "too much data for one table row";       break;
    case SQLITE_CONSTRAINT: z = "constraint failed";                     break;
    case SQLITE_MISMATCH:   z = "datatype mismatch";                     break;
    case SQLITE_MISUSE:     z = "library routine called out of sequence";break;
    case SQLITE_NOLFS:      z = "kernel lacks large file support";       break;
    case SQLITE_AUTH:       z = "authorization denied";                  break;
    case SQLITE_FORMAT:     z = "auxiliary database format error";       break;
    case SQLITE_RANGE:      z = "bind index out of range";               break;
    case SQLITE_NOTADB:     z = "file is encrypted or is not a database";break;
    default:                z = "unknown error";                         break;
  }
  return z;
}

/*
** This routine implements a busy callback that sleeps and tries
** again until a timeout value is reached.  The timeout value is
** an integer number of milliseconds passed in as the first
** argument.
*/
static int sqliteDefaultBusyCallback(
 void *Timeout,           /* Maximum amount of time to wait */
 const char *NotUsed,     /* The name of the table that is busy */
 int count                /* Number of times table has been busy */
){
#if SQLITE_MIN_SLEEP_MS==1
  static const char delays[] =
     { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50,  50, 100};
  static const short int totals[] =
     { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228, 287};
# define NDELAY (sizeof(delays)/sizeof(delays[0]))
  int timeout = (int)(long)Timeout;
  int delay, prior;

  if( count <= NDELAY ){
    delay = delays[count-1];
    prior = totals[count-1];
  }else{
    delay = delays[NDELAY-1];
    prior = totals[NDELAY-1] + delay*(count-NDELAY-1);
  }
  if( prior + delay > timeout ){
    delay = timeout - prior;
    if( delay<=0 ) return 0;
  }
  sqliteOsSleep(delay);
  return 1;
#else
  int timeout = (int)(long)Timeout;
  if( (count+1)*1000 > timeout ){
    return 0;
  }
  sqliteOsSleep(1000);
  return 1;
#endif
}

/*
** This routine sets the busy callback for an Sqlite database to the
** given callback function with the given argument.
*/
void sqlite_busy_handler(
  sqlite *db,
  int (*xBusy)(void*,const char*,int),
  void *pArg
){
  db->xBusyCallback = xBusy;
  db->pBusyArg = pArg;
}

#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
/*
** This routine sets the progress callback for an Sqlite database to the
** given callback function with the given argument. The progress callback will
** be invoked every nOps opcodes.
*/
void sqlite_progress_handler(
  sqlite *db, 
  int nOps,
  int (*xProgress)(void*), 
  void *pArg
){
  if( nOps>0 ){
    db->xProgress = xProgress;
    db->nProgressOps = nOps;
    db->pProgressArg = pArg;
  }else{
    db->xProgress = 0;
    db->nProgressOps = 0;
    db->pProgressArg = 0;
  }
}
#endif


/*
** This routine installs a default busy handler that waits for the
** specified number of milliseconds before returning 0.
*/
void sqlite_busy_timeout(sqlite *db, int ms){
  if( ms>0 ){
    sqlite_busy_handler(db, sqliteDefaultBusyCallback, (void*)(long)ms);
  }else{
    sqlite_busy_handler(db, 0, 0);
  }
}

/*
** Cause any pending operation to stop at its earliest opportunity.
*/
void sqlite_interrupt(sqlite *db){
  db->flags |= SQLITE_Interrupt;
}

/*
** Windows systems should call this routine to free memory that
** is returned in the in the errmsg parameter of sqlite_open() when
** SQLite is a DLL.  For some reason, it does not work to call free()
** directly.
**
** Note that we need to call free() not sqliteFree() here, since every
** string that is exported from SQLite should have already passed through
** sqliteStrRealloc().
*/
void sqlite_freemem(void *p){ free(p); }

/*
** Windows systems need functions to call to return the sqlite_version
** and sqlite_encoding strings since they are unable to access constants
** within DLLs.
*/
const char *sqlite_libversion(void){ return sqlite_version; }
const char *sqlite_libencoding(void){ return sqlite_encoding; }

/*
** Create new user-defined functions.  The sqlite_create_function()
** routine creates a regular function and sqlite_create_aggregate()
** creates an aggregate function.
**
** Passing a NULL xFunc argument or NULL xStep and xFinalize arguments
** disables the function.  Calling sqlite_create_function() with the
** same name and number of arguments as a prior call to
** sqlite_create_aggregate() disables the prior call to
** sqlite_create_aggregate(), and vice versa.
**
** If nArg is -1 it means that this function will accept any number
** of arguments, including 0.  The maximum allowed value of nArg is 127.
*/
int sqlite_create_function(
  sqlite *db,          /* Add the function to this database connection */
  const char *zName,   /* Name of the function to add */
  int nArg,            /* Number of arguments */
  void (*xFunc)(sqlite_func*,int,const char**),  /* The implementation */
  void *pUserData      /* User data */
){
  FuncDef *p;
  int nName;
  if( db==0 || zName==0 || sqliteSafetyCheck(db) ) return 1;
  if( nArg<-1 || nArg>127 ) return 1;
  nName = strlen(zName);
  if( nName>255 ) return 1;
  p = sqliteFindFunction(db, zName, nName, nArg, 1);
  if( p==0 ) return 1;
  p->xFunc = xFunc;
  p->xStep = 0;
  p->xFinalize = 0;
  p->pUserData = pUserData;
  return 0;
}
int sqlite_create_aggregate(
  sqlite *db,          /* Add the function to this database connection */
  const char *zName,   /* Name of the function to add */
  int nArg,            /* Number of arguments */
  void (*xStep)(sqlite_func*,int,const char**), /* The step function */
  void (*xFinalize)(sqlite_func*),              /* The finalizer */
  void *pUserData      /* User data */
){
  FuncDef *p;
  int nName;
  if( db==0 || zName==0 || sqliteSafetyCheck(db) ) return 1;
  if( nArg<-1 || nArg>127 ) return 1;
  nName = strlen(zName);
  if( nName>255 ) return 1;
  p = sqliteFindFunction(db, zName, nName, nArg, 1);
  if( p==0 ) return 1;
  p->xFunc = 0;
  p->xStep = xStep;
  p->xFinalize = xFinalize;
  p->pUserData = pUserData;
  return 0;
}

/*
** Change the datatype for all functions with a given name.  See the
** header comment for the prototype of this function in sqlite.h for
** additional information.
*/
int sqlite_function_type(sqlite *db, const char *zName, int dataType){
  FuncDef *p = (FuncDef*)sqliteHashFind(&db->aFunc, zName, strlen(zName));
  while( p ){
    p->dataType = dataType; 
    p = p->pNext;
  }
  return SQLITE_OK;
}

/*
** 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
** sqlite_exec().
*/
void *sqlite_trace(sqlite *db, void (*xTrace)(void*,const char*), void *pArg){
  void *pOld = db->pTraceArg;
  db->xTrace = xTrace;
  db->pTraceArg = pArg;
  return pOld;
}

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


/*
** 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 for temporary use only and is deleted as soon as the connection
** is closed.
**
** A temporary database can be either a disk file (that is automatically
** deleted when the file is closed) or a set of red-black trees held in memory,
** depending on the values of the TEMP_STORE compile-time macro and the
** db->temp_store variable, according to the following chart:
**
**       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 sqliteBtreeFactory(
  const sqlite *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 */
  Btree **ppBtree){         /* Pointer to new Btree object written here */

  assert( ppBtree != 0);

#ifndef SQLITE_OMIT_INMEMORYDB
  if( zFilename==0 ){
    if (TEMP_STORE == 0) {
      /* Always use file based temporary DB */
      return sqliteBtreeOpen(0, omitJournal, nCache, ppBtree);
    } else if (TEMP_STORE == 1 || TEMP_STORE == 2) {
      /* Switch depending on compile-time and/or runtime settings. */
      int location = db->temp_store==0 ? TEMP_STORE : db->temp_store;

      if (location == 1) {
        return sqliteBtreeOpen(zFilename, omitJournal, nCache, ppBtree);
      } else {
        return sqliteRbtreeOpen(0, 0, 0, ppBtree);
      }
    } else {
      /* Always use in-core DB */
      return sqliteRbtreeOpen(0, 0, 0, ppBtree);
    }
  }else if( zFilename[0]==':' && strcmp(zFilename,":memory:")==0 ){
    return sqliteRbtreeOpen(0, 0, 0, ppBtree);
  }else
#endif
  {
    return sqliteBtreeOpen(zFilename, omitJournal, nCache, ppBtree);
  }
}