sqlite3/prepare.c

   1 /*
   2 ** 2005 May 25
   3 **
   4 ** The author disclaims copyright to this source code.  In place of
   5 ** a legal notice, here is a blessing:
   6 **
   7 **    May you do good and not evil.
   8 **    May you find forgiveness for yourself and forgive others.
   9 **    May you share freely, never taking more than you give.
  10 **
  11 *************************************************************************
  12 ** This file contains the implementation of the sqlite3_prepare()
  13 ** interface, and routines that contribute to loading the database schema
  14 ** from disk.
  15 **
  16 ** $Id$
  17 */
  18 #include "sqliteInt.h"
  19 #include "os.h"
  20 #include <ctype.h>
  21
  22 /*
  23 ** Fill the InitData structure with an error message that indicates
  24 ** that the database is corrupt.
  25 */
  26 static void corruptSchema(InitData *pData, const char *zExtra){
  27   if( !sqlite3_malloc_failed ){
  28     sqlite3SetString(pData->pzErrMsg, "malformed database schema",
  29        zExtra!=0 && zExtra[0]!=0 ? " - " : (char*)0, zExtra, (char*)0);
  30   }
  31 }
  32
  33 /*
  34 ** This is the callback routine for the code that initializes the
  35 ** database.  See sqlite3Init() below for additional information.
  36 ** This routine is also called from the OP_ParseSchema opcode of the VDBE.
  37 **
  38 ** Each callback contains the following information:
  39 **
  40 **     argv[0] = name of thing being created
  41 **     argv[1] = root page number for table or index.  NULL for trigger or view.
  42 **     argv[2] = SQL text for the CREATE statement.
  43 **     argv[3] = "1" for temporary files, "0" for main database, "2" or more
  44 **               for auxiliary database files.
  45 **
  46 */
  47 int sqlite3InitCallback(void *pInit, int argc, char **argv, char **azColName){
  48   InitData *pData = (InitData*)pInit;
  49   sqlite3 *db = pData->db;
  50   int iDb;
  51
  52   assert( argc==4 );
  53   if( argv==0 ) return 0;   /* Might happen if EMPTY_RESULT_CALLBACKS are on */
  54   if( argv[1]==0 || argv[3]==0 ){
  55     corruptSchema(pData, 0);
  56     return 1;
  57   }
  58   iDb = atoi(argv[3]);
  59   assert( iDb>=0 && iDb<db->nDb );
  60   if( argv[2] && argv[2][0] ){
  61     /* Call the parser to process a CREATE TABLE, INDEX or VIEW.
  62     ** But because db->init.busy is set to 1, no VDBE code is generated
  63     ** or executed.  All the parser does is build the internal data
  64     ** structures that describe the table, index, or view.
  65     */
  66     char *zErr;
  67     int rc;
  68     assert( db->init.busy );
  69     db->init.iDb = iDb;
  70     db->init.newTnum = atoi(argv[1]);
  71     rc = sqlite3_exec(db, argv[2], 0, 0, &zErr);
  72     db->init.iDb = 0;
  73     if( SQLITE_OK!=rc ){
  74       corruptSchema(pData, zErr);
  75       sqlite3_free(zErr);
  76       return rc;
  77     }
  78   }else{
  79     /* If the SQL column is blank it means this is an index that
  80     ** was created to be the PRIMARY KEY or to fulfill a UNIQUE
  81     ** constraint for a CREATE TABLE.  The index should have already
  82     ** been created when we processed the CREATE TABLE.  All we have
  83     ** to do here is record the root page number for that index.
  84     */
  85     Index *pIndex;
  86     pIndex = sqlite3FindIndex(db, argv[0], db->aDb[iDb].zName);
  87     if( pIndex==0 || pIndex->tnum!=0 ){
  88       /* This can occur if there exists an index on a TEMP table which
  89       ** has the same name as another index on a permanent index.  Since
  90       ** the permanent table is hidden by the TEMP table, we can also
  91       ** safely ignore the index on the permanent table.
  92       */
  93       /* Do Nothing */;
  94     }else{
  95       pIndex->tnum = atoi(argv[1]);
  96     }
  97   }
  98   return 0;
  99 }
 100
 101 /*
 102 ** Attempt to read the database schema and initialize internal
 103 ** data structures for a single database file.  The index of the
 104 ** database file is given by iDb.  iDb==0 is used for the main
 105 ** database.  iDb==1 should never be used.  iDb>=2 is used for
 106 ** auxiliary databases.  Return one of the SQLITE_ error codes to
 107 ** indicate success or failure.
 108 */
 109 static int sqlite3InitOne(sqlite3 *db, int iDb, STRPTR *pzErrMsg){
 110   int rc;
 111   BtCursor *curMain;
 112   int size;
 113   Table *pTab;
 114   char const *azArg[5];
 115   char zDbNum[30];
 116   int meta[10];
 117   InitData initData;
 118   char const *zMasterSchema;
 119   char const *zMasterName = SCHEMA_TABLE(iDb);
 120
 121   /*
 122   ** The master database table has a structure like this
 123   */
 124   static const char master_schema[] =
 125      "CREATE TABLE sqlite_master(\n"
 126      "  type text,\n"
 127      "  name text,\n"
 128      "  tbl_name text,\n"
 129      "  rootpage integer,\n"
 130      "  sql text\n"
 131      ")"
 132   ;
 133 #ifndef SQLITE_OMIT_TEMPDB
 134   static const char temp_master_schema[] =
 135      "CREATE TEMP TABLE sqlite_temp_master(\n"
 136      "  type text,\n"
 137      "  name text,\n"
 138      "  tbl_name text,\n"
 139      "  rootpage integer,\n"
 140      "  sql text\n"
 141      ")"
 142   ;
 143 #else
 144   #define temp_master_schema 0
 145 #endif
 146
 147   assert( iDb>=0 && iDb<db->nDb );
 148
 149   /* zMasterSchema and zInitScript are set to point at the master schema
 150   ** and initialisation script appropriate for the database being
 151   ** initialised. zMasterName is the name of the master table.
 152   */
 153   if( !OMIT_TEMPDB && iDb==1 ){
 154     zMasterSchema = temp_master_schema;
 155   }else{
 156     zMasterSchema = master_schema;
 157   }
 158   zMasterName = SCHEMA_TABLE(iDb);
 159
 160   /* Construct the schema tables.  */
 161   sqlite3SafetyOff(db);
 162   azArg[0] = zMasterName;
 163   azArg[1] = "1";
 164   azArg[2] = zMasterSchema;
 165   sprintf(zDbNum, "%d", iDb);
 166   azArg[3] = zDbNum;
 167   azArg[4] = 0;
 168   initData.db = db;
 169   initData.pzErrMsg = pzErrMsg;
 170   rc = sqlite3InitCallback(&initData, 4, (char **)azArg, 0);
 171   if( rc!=SQLITE_OK ){
 172     sqlite3SafetyOn(db);
 173     return rc;
 174   }
 175   pTab = sqlite3FindTable(db, zMasterName, db->aDb[iDb].zName);
 176   if( pTab ){
 177     pTab->readOnly = 1;
 178   }
 179   sqlite3SafetyOn(db);
 180
 181   /* Create a cursor to hold the database open
 182   */
 183   if( db->aDb[iDb].pBt==0 ){
 184     if( !OMIT_TEMPDB && iDb==1 ) DbSetProperty(db, 1, DB_SchemaLoaded);
 185     return SQLITE_OK;
 186   }
 187   rc = sqlite3BtreeCursor(db->aDb[iDb].pBt, MASTER_ROOT, 0, 0, 0, &curMain);
 188   if( rc!=SQLITE_OK && rc!=SQLITE_EMPTY ){
 189     sqlite3SetString(pzErrMsg, sqlite3ErrStr(rc), (char*)0);
 190     return rc;
 191   }
 192
 193   /* Get the database meta information.
 194   **
 195   ** Meta values are as follows:
 196   **    meta[0]   Schema cookie.  Changes with each schema change.
 197   **    meta[1]   File format of schema layer.
 198   **    meta[2]   Size of the page cache.
 199   **    meta[3]   Use freelist if 0.  Autovacuum if greater than zero.
 200   **    meta[4]   Db text encoding. 1:UTF-8 3:UTF-16 LE 4:UTF-16 BE
 201   **    meta[5]   The user cookie. Used by the application.
 202   **    meta[6]
 203   **    meta[7]
 204   **    meta[8]
 205   **    meta[9]
 206   **
 207   ** Note: The hash defined SQLITE_UTF* symbols in sqliteInt.h correspond to
 208   ** the possible values of meta[4].
 209   */
 210   if( rc==SQLITE_OK ){
 211     int i;
 212     for(i=0; rc==SQLITE_OK && i<sizeof(meta)/sizeof(meta[0]); i++){
 213       rc = sqlite3BtreeGetMeta(db->aDb[iDb].pBt, i+1, (u32 *)&meta[i]);
 214     }
 215     if( rc ){
 216       sqlite3SetString(pzErrMsg, sqlite3ErrStr(rc), (char*)0);
 217       sqlite3BtreeCloseCursor(curMain);
 218       return rc;
 219     }
 220   }else{
 221     memset(meta, 0, sizeof(meta));
 222   }
 223   db->aDb[iDb].schema_cookie = meta[0];
 224
 225   /* If opening a non-empty database, check the text encoding. For the
 226   ** main database, set sqlite3.enc to the encoding of the main database.
 227   ** For an attached db, it is an error if the encoding is not the same
 228   ** as sqlite3.enc.
 229   */
 230   if( meta[4] ){  /* text encoding */
 231     if( iDb==0 ){
 232       /* If opening the main database, set db->enc. */
 233       db->enc = (u8)meta[4];
 234       db->pDfltColl = sqlite3FindCollSeq(db, db->enc, "BINARY", 6, 0);
 235     }else{
 236       /* If opening an attached database, the encoding much match db->enc */
 237       if( meta[4]!=db->enc ){
 238         sqlite3BtreeCloseCursor(curMain);
 239         sqlite3SetString(pzErrMsg, "attached databases must use the same"
 240             " text encoding as main database", (char*)0);
 241         return SQLITE_ERROR;
 242       }
 243     }
 244   }
 245
 246   size = meta[2];
 247   if( size==0 ){ size = MAX_PAGES; }
 248   db->aDb[iDb].cache_size = size;
 249
 250   if( iDb==0 ){
 251     db->file_format = meta[1];
 252     if( db->file_format==0 ){
 253       /* This happens if the database was initially empty */
 254       db->file_format = 1;
 255     }
 256
 257     if( db->file_format==2 || db->file_format==3 ){
 258       /* File format 2 is treated exactly as file format 1. New
 259       ** databases are created with file format 1.
 260       */
 261       db->file_format = 1;
 262     }
 263   }
 264
 265   /*
 266   ** file_format==1    Version 3.0.0.
 267   ** file_format==2    Version 3.1.3.
 268   ** file_format==3    Version 3.1.4.
 269   **
 270   ** Version 3.0 can only use files with file_format==1. Version 3.1.3
 271   ** can read and write files with file_format==1 or file_format==2.
 272   ** Version 3.1.4 can read and write file formats 1, 2 and 3.
 273   */
 274   if( meta[1]>3 ){
 275     sqlite3BtreeCloseCursor(curMain);
 276     sqlite3SetString(pzErrMsg, "unsupported file format", (char*)0);
 277     return SQLITE_ERROR;
 278   }
 279
 280   sqlite3BtreeSetCacheSize(db->aDb[iDb].pBt, db->aDb[iDb].cache_size);
 281
 282   /* Read the schema information out of the schema tables
 283   */
 284   assert( db->init.busy );
 285   if( rc==SQLITE_EMPTY ){
 286     /* For an empty database, there is nothing to read */
 287     rc = SQLITE_OK;
 288   }else{
 289     char *zSql;
 290     zSql = sqlite3MPrintf(
 291         "SELECT name, rootpage, sql, '%s' FROM '%q'.%s",
 292         zDbNum, db->aDb[iDb].zName, zMasterName);
 293     sqlite3SafetyOff(db);
 294     rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
 295     sqlite3SafetyOn(db);
 296     sqliteFree(zSql);
 297     sqlite3BtreeCloseCursor(curMain);
 298   }
 299   if( sqlite3_malloc_failed ){
 300     sqlite3SetString(pzErrMsg, "out of memory", (char*)0);
 301     rc = SQLITE_NOMEM;
 302     sqlite3ResetInternalSchema(db, 0);
 303   }
 304   if( rc==SQLITE_OK ){
 305     DbSetProperty(db, iDb, DB_SchemaLoaded);
 306   }else{
 307     sqlite3ResetInternalSchema(db, iDb);
 308   }
 309   return rc;
 310 }
 311
 312 /*
 313 ** Initialize all database files - the main database file, the file
 314 ** used to store temporary tables, and any additional database files
 315 ** created using ATTACH statements.  Return a success code.  If an
 316 ** error occurs, write an error message into *pzErrMsg.
 317 **
 318 ** After the database is initialized, the SQLITE_Initialized
 319 ** bit is set in the flags field of the sqlite structure.
 320 */
 321 int sqlite3Init(sqlite3 *db, STRPTR *pzErrMsg){
 322   int i, rc;
 323
 324   if( db->init.busy ) return SQLITE_OK;
 325   assert( (db->flags & SQLITE_Initialized)==0 );
 326   rc = SQLITE_OK;
 327   db->init.busy = 1;
 328   for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
 329     if( DbHasProperty(db, i, DB_SchemaLoaded) || i==1 ) continue;
 330     rc = sqlite3InitOne(db, i, pzErrMsg);
 331     if( rc ){
 332       sqlite3ResetInternalSchema(db, i);
 333     }
 334   }
 335
 336   /* Once all the other databases have been initialised, load the schema
 337   ** for the TEMP database. This is loaded last, as the TEMP database
 338   ** schema may contain references to objects in other databases.
 339   */
 340 #ifndef SQLITE_OMIT_TEMPDB
 341   if( rc==SQLITE_OK && db->nDb>1 && !DbHasProperty(db, 1, DB_SchemaLoaded) ){
 342     rc = sqlite3InitOne(db, 1, pzErrMsg);
 343     if( rc ){
 344       sqlite3ResetInternalSchema(db, 1);
 345     }
 346   }
 347 #endif
 348
 349   db->init.busy = 0;
 350   if( rc==SQLITE_OK ){
 351     db->flags |= SQLITE_Initialized;
 352     sqlite3CommitInternalChanges(db);
 353   }
 354
 355   if( rc!=SQLITE_OK ){
 356     db->flags &= ~SQLITE_Initialized;
 357   }
 358   return rc;
 359 }
 360
 361 /*
 362 ** This routine is a no-op if the database schema is already initialised.
 363 ** Otherwise, the schema is loaded. An error code is returned.
 364 */
 365 int sqlite3ReadSchema(Parse *pParse){
 366   int rc = SQLITE_OK;
 367   sqlite3 *db = pParse->db;
 368   if( !db->init.busy ){
 369     if( (db->flags & SQLITE_Initialized)==0 ){
 370       rc = sqlite3Init(db, &pParse->zErrMsg);
 371     }
 372   }
 373   assert( rc!=SQLITE_OK || (db->flags & SQLITE_Initialized)||db->init.busy );
 374   if( rc!=SQLITE_OK ){
 375     pParse->rc = rc;
 376     pParse->nErr++;
 377   }
 378   return rc;
 379 }
 380
 381
 382 /*
 383 ** Check schema cookies in all databases.  If any cookie is out
 384 ** of date, return 0.  If all schema cookies are current, return 1.
 385 */
 386 static int schemaIsValid(sqlite3 *db){
 387   int iDb;
 388   int rc;
 389   BtCursor *curTemp;
 390   int cookie;
 391   int allOk = 1;
 392
 393   for(iDb=0; allOk && iDb<db->nDb; iDb++){
 394     Btree *pBt;
 395     pBt = db->aDb[iDb].pBt;
 396     if( pBt==0 ) continue;
 397     rc = sqlite3BtreeCursor(pBt, MASTER_ROOT, 0, 0, 0, &curTemp);
 398     if( rc==SQLITE_OK ){
 399       rc = sqlite3BtreeGetMeta(pBt, 1, (u32 *)&cookie);
 400       if( rc==SQLITE_OK && cookie!=db->aDb[iDb].schema_cookie ){
 401         allOk = 0;
 402       }
 403       sqlite3BtreeCloseCursor(curTemp);
 404     }
 405   }
 406   return allOk;
 407 }
 408
 409 /*
 410 ** Compile the UTF-8 encoded SQL statement zSql into a statement handle.
 411 */
 412 int sqlite3_prepare(
 413   sqlite3 *db,              /* Database handle. */
 414   const char *zSql,         /* UTF-8 encoded SQL statement. */
 415   int nBytes,               /* Length of zSql in bytes. */
 416   sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
 417   const char** pzTail       /* OUT: End of parsed string */
 418 ){
 419   Parse sParse;
 420   STRPTR zErrMsg = NULL;
 421   int rc = SQLITE_OK;
 422
 423   if( sqlite3_malloc_failed ){
 424     return SQLITE_NOMEM;
 425   }
 426
 427   assert( ppStmt );
 428   *ppStmt = 0;
 429   if( sqlite3SafetyOn(db) ){
 430     return SQLITE_MISUSE;
 431   }
 432
 433   memset(&sParse, 0, sizeof(sParse));
 434   sParse.db = db;
 435   sqlite3RunParser(&sParse, zSql, &zErrMsg);
 436
 437   if( sqlite3_malloc_failed ){
 438     rc = SQLITE_NOMEM;
 439     sqlite3RollbackAll(db);
 440     sqlite3ResetInternalSchema(db, 0);
 441     db->flags &= ~SQLITE_InTrans;
 442     goto prepare_out;
 443   }
 444   if( sParse.rc==SQLITE_DONE ) sParse.rc = SQLITE_OK;
 445   if( sParse.rc!=SQLITE_OK && sParse.checkSchema && !schemaIsValid(db) ){
 446     sParse.rc = SQLITE_SCHEMA;
 447   }
 448   if( sParse.rc==SQLITE_SCHEMA ){
 449     sqlite3ResetInternalSchema(db, 0);
 450   }
 451   if( pzTail ) *pzTail = sParse.zTail;
 452   rc = sParse.rc;
 453
 454 #ifndef SQLITE_OMIT_EXPLAIN
 455   if( rc==SQLITE_OK && sParse.pVdbe && sParse.explain ){
 456     sqlite3VdbeSetNumCols(sParse.pVdbe, 5);
 457     sqlite3VdbeSetColName(sParse.pVdbe, 0, "addr", P3_STATIC);
 458     sqlite3VdbeSetColName(sParse.pVdbe, 1, "opcode", P3_STATIC);
 459     sqlite3VdbeSetColName(sParse.pVdbe, 2, "p1", P3_STATIC);
 460     sqlite3VdbeSetColName(sParse.pVdbe, 3, "p2", P3_STATIC);
 461     sqlite3VdbeSetColName(sParse.pVdbe, 4, "p3", P3_STATIC);
 462   }
 463 #endif
 464
 465 prepare_out:
 466   if( sqlite3SafetyOff(db) ){
 467     rc = SQLITE_MISUSE;
 468   }
 469   if( rc==SQLITE_OK ){
 470     *ppStmt = (sqlite3_stmt*)sParse.pVdbe;
 471   }else if( sParse.pVdbe ){
 472     sqlite3_finalize((sqlite3_stmt*)sParse.pVdbe);
 473   }
 474
 475   if( zErrMsg ){
 476     sqlite3Error(db, rc, "%s", zErrMsg);
 477     sqliteFree(zErrMsg);
 478   }else{
 479     sqlite3Error(db, rc, 0);
 480   }
 481   return rc;
 482 }
 483
 484 #ifndef SQLITE_OMIT_UTF16
 485 /*
 486 ** Compile the UTF-16 encoded SQL statement zSql into a statement handle.
 487 */
 488 int sqlite3_prepare16(
 489   sqlite3 *db,              /* Database handle. */
 490   const void *zSql,         /* UTF-8 encoded SQL statement. */
 491   int nBytes,               /* Length of zSql in bytes. */
 492   sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
 493   const void **pzTail       /* OUT: End of parsed string */
 494 ){
 495   /* This function currently works by first transforming the UTF-16
 496   ** encoded string to UTF-8, then invoking sqlite3_prepare(). The
 497   ** tricky bit is figuring out the pointer to return in *pzTail.
 498   */
 499   char const *zSql8 = 0;
 500   char const *zTail8 = 0;
 501   int rc;
 502   sqlite3_value *pTmp;
 503
 504   if( sqlite3SafetyCheck(db) ){
 505     return SQLITE_MISUSE;
 506   }
 507   pTmp = sqlite3GetTransientValue(db);
 508   sqlite3ValueSetStr(pTmp, -1, zSql, SQLITE_UTF16NATIVE, SQLITE_STATIC);
 509   zSql8 = sqlite3ValueText(pTmp, SQLITE_UTF8);
 510   if( !zSql8 ){
 511     sqlite3Error(db, SQLITE_NOMEM, 0);
 512     return SQLITE_NOMEM;
 513   }
 514   rc = sqlite3_prepare(db, zSql8, -1, ppStmt, &zTail8);
 515
 516   if( zTail8 && pzTail ){
 517     /* If sqlite3_prepare returns a tail pointer, we calculate the
 518     ** equivalent pointer into the UTF-16 string by counting the unicode
 519     ** characters between zSql8 and zTail8, and then returning a pointer
 520     ** the same number of characters into the UTF-16 string.
 521     */
 522     int chars_parsed = sqlite3utf8CharLen(zSql8, zTail8-zSql8);
 523     *pzTail = (u8 *)zSql + sqlite3utf16ByteLen(zSql, chars_parsed);
 524   }
 525
 526   return rc;
 527 }
 528 #endif /* SQLITE_OMIT_UTF16 */
 529