SQLite

/*
** The code in this file only exists if we are not omitting the
** ALTER TABLE logic from the build.
*/
#ifndef SQLITE_OMIT_ALTERTABLE

/*
** This function is used to create the text of expressions of the form:
**
**   name=<constant1> OR name=<constant2> OR ...
**
** If argument zWhere is NULL, then a pointer string containing the text 
** "name=<constant>" is returned, where <constant> is the quoted version
** of the string passed as argument zConstant. The returned buffer is
** allocated using sqlite3DbMalloc(). It is the responsibility of the
** caller to ensure that it is eventually freed.
**
** If argument zWhere is not NULL, then the string returned is 
** "<where> OR name=<constant>", where <where> is the contents of zWhere.
** In this case zWhere is passed to sqlite3DbFree() before returning.
** 
*/
static char *whereOrName(sqlite3 *db, char *zWhere, char *zConstant){
  char *zNew;
  if( !zWhere ){
    zNew = sqlite3MPrintf(db, "name=%Q", zConstant);
  }else{
    zNew = sqlite3MPrintf(db, "%s OR name=%Q", zWhere, zConstant);
    sqlite3DbFree(db, zWhere);
  }
  return zNew;
}

#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
/*
** Generate the text of a WHERE expression which can be used to select all
** tables that have foreign key constraints that refer to table pTab (i.e.
** constraints for which pTab is the parent table) from the sqlite_master
** table.
*/
static char *whereForeignKeys(Parse *pParse, Table *pTab){
  FKey *p;
  char *zWhere = 0;
  for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
    zWhere = whereOrName(pParse->db, zWhere, p->pFrom->zName);
  }
  return zWhere;
}
#endif

/*
** Generate the text of a WHERE expression which can be used to select all
** temporary triggers on table pTab from the sqlite_temp_master table. If
** table pTab has no temporary triggers, or is itself stored in the 
** temporary database, NULL is returned.
*/
static char *whereTempTriggers(Parse *pParse, Table *pTab){
  Trigger *pTrig;
  char *zWhere = 0;
  const Schema *pTempSchema = pParse->db->aDb[1].pSchema; /* Temp db schema */

  /* If the table is not located in the temp-db (in which case NULL is 
  ** returned, loop through the tables list of triggers. For each trigger
  ** that is not part of the temp-db schema, add a clause to the WHERE 
  ** expression being built up in zWhere.
  */
  if( pTab->pSchema!=pTempSchema ){
    sqlite3 *db = pParse->db;
    for(pTrig=sqlite3TriggerList(pParse, pTab); pTrig; pTrig=pTrig->pNext){
      if( pTrig->pSchema==pTempSchema ){
        zWhere = whereOrName(db, zWhere, pTrig->zName);
      }
    }
  }
  if( zWhere ){
    char *zNew = sqlite3MPrintf(pParse->db, "type='trigger' AND (%s)", zWhere);
    sqlite3DbFree(pParse->db, zWhere);
    zWhere = zNew;
  }
  return zWhere;
}

/*
** Generate code to drop and reload the internal representation of table
** pTab from the database, including triggers and temporary triggers.
** Argument zName is the name of the table in the database schema at
** the time the generated code is executed. This can be different from
** pTab->zName if this function is being called to code part of an 
** "ALTER TABLE RENAME TO" statement.
*/
static void reloadTableSchema(Parse *pParse, Table *pTab, const char *zName){
  Vdbe *v;
  char *zWhere;
  int iDb;                   /* Index of database containing pTab */
#ifndef SQLITE_OMIT_TRIGGER
  Trigger *pTrig;
#endif

  v = sqlite3GetVdbe(pParse);
  if( NEVER(v==0) ) return;
  assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  assert( iDb>=0 );

#ifndef SQLITE_OMIT_TRIGGER
  /* Drop any table triggers from the internal schema. */
  for(pTrig=sqlite3TriggerList(pParse, pTab); pTrig; pTrig=pTrig->pNext){
    int iTrigDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
    assert( iTrigDb==iDb || iTrigDb==1 );
    sqlite3VdbeAddOp4(v, OP_DropTrigger, iTrigDb, 0, 0, pTrig->zName, 0);
  }
#endif

  /* Drop the table and index from the internal schema.  */
  sqlite3VdbeAddOp4(v, OP_DropTable, iDb, 0, 0, pTab->zName, 0);

  /* Reload the table, index and permanent trigger schemas. */
  zWhere = sqlite3MPrintf(pParse->db, "tbl_name=%Q", zName);
  if( !zWhere ) return;
  sqlite3VdbeAddParseSchemaOp(v, iDb, zWhere);

#ifndef SQLITE_OMIT_TRIGGER
  /* Now, if the table is not stored in the temp database, reload any temp 
  ** triggers. Don't use IN(...) in case SQLITE_OMIT_SUBQUERY is defined. 
  */
  if( (zWhere=whereTempTriggers(pParse, pTab))!=0 ){
    sqlite3VdbeAddParseSchemaOp(v, 1, zWhere);
  }
#endif
}

/*
** Parameter zName is the name of a table that is about to be altered
** (either with ALTER TABLE ... RENAME TO or ALTER TABLE ... ADD COLUMN).
** If the table is a system table, this function leaves an error message
** in pParse->zErr (system tables may not be altered) and returns non-zero.
**
** Or, if zName is not a system table, zero is returned.
*/
static int isSystemTable(Parse *pParse, const char *zName){
  if( 0==sqlite3StrNICmp(zName, "sqlite_", 7) ){
    sqlite3ErrorMsg(pParse, "table %s may not be altered", zName);
    return 1;
  }
  return 0;
}








void renameTestSchema(Parse *pParse, const char *zDb, int bTemp){
  sqlite3NestedParse(pParse, 
      "SELECT 1 "
      "FROM \"%w\".%s "
      "WHERE name NOT LIKE 'sqlite_%%'"
      " AND sql NOT LIKE 'create virtual%%'"
      " AND sqlite_rename_test(%Q, sql, type, name, %d)=0 ",

        "WHERE name NOT LIKE 'sqlite_%%'"
        " AND sql NOT LIKE 'create virtual%%'"
        " AND sqlite_rename_test(%Q, sql, type, name, 1)=0 ",
        MASTER_NAME, zDb 
    );
  }
}














/*
** Generate code to implement the "ALTER TABLE xxx RENAME TO yyy" 
** command. 
*/
void sqlite3AlterRenameTable(
  Parse *pParse,            /* Parser context. */

  ** schema). Open a statement transaction if the table is a virtual
  ** table.
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ){
    goto exit_rename_table;
  }
  sqlite3BeginWriteOperation(pParse, pVTab!=0, iDb);
  sqlite3ChangeCookie(pParse, iDb);

  /* If this is a virtual table, invoke the xRename() function if
  ** one is defined. The xRename() callback will modify the names
  ** of any resources used by the v-table implementation (including other
  ** SQLite tables) that are identified by the name of the virtual table.
  */
#ifndef SQLITE_OMIT_VIRTUALTABLE

            "sql = sqlite_rename_table(%Q, sql, %Q, %Q, 1), "
            "tbl_name = "
              "CASE WHEN tbl_name=%Q COLLATE nocase THEN %Q ELSE tbl_name END "
            "WHERE type IN ('view', 'trigger')"
        , zDb, zTabName, zName, zTabName, zTabName, zName);
  }

  sqlite3VdbeAddParseSchemaOp(pParse->pVdbe, iDb, 0);
  if( iDb!=1 ) sqlite3VdbeAddParseSchemaOp(pParse->pVdbe, 1, 0);

  renameTestSchema(pParse, zDb, iDb==1);

exit_rename_table:
  sqlite3SrcListDelete(db, pSrc);
  sqlite3DbFree(db, zName);
  db->mDbFlags = savedDbFlags;
}

  int iDb;                  /* Database number */
  const char *zDb;          /* Database name */
  const char *zTab;         /* Table name */
  char *zCol;               /* Null-terminated column definition */
  Column *pCol;             /* The new column */
  Expr *pDflt;              /* Default value for the new column */
  sqlite3 *db;              /* The database connection; */
  Vdbe *v = pParse->pVdbe;  /* The prepared statement under construction */
  int r1;                   /* Temporary registers */


  db = pParse->db;
  if( pParse->nErr || db->mallocFailed ) return;
  assert( v!=0 );
  pNew = pParse->pNewTable;
  assert( pNew );

  assert( sqlite3BtreeHoldsAllMutexes(db) );
  iDb = sqlite3SchemaToIndex(db, pNew->pSchema);
  zDb = db->aDb[iDb].zDbSName;
  zTab = &pNew->zName[16];  /* Skip the "sqlite_altertab_" prefix on the name */

    db->mDbFlags = savedDbFlags;
  }

  /* Make sure the schema version is at least 3.  But do not upgrade
  ** from less than 3 to 4, as that will corrupt any preexisting DESC
  ** index.
  */


  r1 = sqlite3GetTempReg(pParse);
  sqlite3VdbeAddOp3(v, OP_ReadCookie, iDb, r1, BTREE_FILE_FORMAT);
  sqlite3VdbeUsesBtree(v, iDb);
  sqlite3VdbeAddOp2(v, OP_AddImm, r1, -2);
  sqlite3VdbeAddOp2(v, OP_IfPos, r1, sqlite3VdbeCurrentAddr(v)+2);
  VdbeCoverage(v);
  sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_FILE_FORMAT, 3);
  sqlite3ReleaseTempReg(pParse, r1);


  /* Reload the schema of the modified table. */
  reloadTableSchema(pParse, pTab, pTab->zName);
}

/*
** This function is called by the parser after the table-name in
** an "ALTER TABLE <table-name> ADD" statement is parsed. Argument 
** pSrc is the full-name of the table being altered.
**

    pCol->zColl = 0;
    pCol->pDflt = 0;
  }
  pNew->pSchema = db->aDb[iDb].pSchema;
  pNew->addColOffset = pTab->addColOffset;
  pNew->nTabRef = 1;

  /* Begin a transaction and increment the schema cookie.  */
  sqlite3BeginWriteOperation(pParse, 0, iDb);
  v = sqlite3GetVdbe(pParse);
  if( !v ) goto exit_begin_add_column;
  sqlite3ChangeCookie(pParse, iDb);

exit_begin_add_column:
  sqlite3SrcListDelete(db, pSrc);
  return;
}

/*
** Parameter pTab is the subject of an ALTER TABLE ... RENAME COLUMN

      "sql = sqlite_rename_column(sql, type, name, %Q, %Q, %d, %Q, %d) "
      "WHERE type IN ('trigger', 'view')",
      MASTER_NAME, 
      zDb, pTab->zName, iCol, zNew, bQuote
  );

  /* Drop and reload the database schema. */
  if( pParse->pVdbe ){
    sqlite3ChangeCookie(pParse, iSchema);
    sqlite3VdbeAddParseSchemaOp(pParse->pVdbe, iSchema, 0);
    if( iSchema!=1 ) sqlite3VdbeAddParseSchemaOp(pParse->pVdbe, 1, 0);
  }

  renameTestSchema(pParse, zDb, iSchema==1);

 exit_rename_column:
  sqlite3SrcListDelete(db, pSrc);
  sqlite3DbFree(db, zOld);
  sqlite3DbFree(db, zNew);
  return;

  int iCol;                       /* Index of column being renamed */
  Table *pTab;                    /* Table being ALTERed */ 
  const char *zOld;               /* Old column name */
};

void renameTokenClear(Parse *pParse, void *pPtr){
  RenameToken *p;
  assert( pPtr );
  for(p=pParse->pRename; p; p=p->pNext){
    if( p->p==pPtr ){
      p->p = 0;
    }
  }
}

  int NotUsed,
  sqlite3_value **argv
){
  sqlite3 *db = sqlite3_context_db_handle(context);
  unsigned char const *zDb = sqlite3_value_text(argv[0]);
  unsigned char const *zInput = sqlite3_value_text(argv[1]);
  int bTemp = sqlite3_value_int(argv[4]);
  int rc;
  Parse sParse;

#ifndef SQLITE_OMIT_AUTHORIZATION
  sqlite3_xauth xAuth = db->xAuth;
  db->xAuth = 0;
#endif




  rc = renameParseSql(&sParse, zDb, 1, db, zInput, bTemp);
  if( rc==SQLITE_OK ){
    if( sParse.pNewTable && sParse.pNewTable->pSelect ){
      NameContext sNC;
      memset(&sNC, 0, sizeof(sNC));
      sNC.pParse = &sParse;
      sqlite3SelectPrep(&sParse, sParse.pNewTable->pSelect, &sNC);
      if( sParse.nErr ) rc = sParse.rc;
    }

    else if( sParse.pNewTrigger ){
      rc = renameResolveTrigger(&sParse, bTemp ? 0 : zDb);
    }
  }

  if( rc!=SQLITE_OK ){
    renameColumnParseError(context, 1, argv[2], argv[3], &sParse);
  }
  renameParseCleanup(&sParse);


#ifndef SQLITE_OMIT_AUTHORIZATION
  db->xAuth = xAuth;
#endif
}

/*