}    sqliteVdbeAddOp(v, OP_NewRecno, 0, 0);    sqliteVdbeOp3(v, OP_String, 0, 0, "index", P3_STATIC);    sqliteVdbeOp3(v, OP_String, 0, 0, pIndex->zName, 0);    sqliteVdbeOp3(v, OP_String, 0, 0, pTab->zName, 0);    sqliteVdbeOp3(v, OP_CreateIndex, 0, isTemp,(char*)&pIndex->tnum,P3_POINTER);    pIndex->tnum = 0;    if( pTable ){      sqliteVdbeCode(v,          OP_Dup,       0,      0,          OP_Integer,   isTemp, 0,          OP_OpenWrite, 1,      0,      0);    }    addr = sqliteVdbeAddOp(v, OP_String, 0, 0);    if( pStart && pEnd ){      n = Addr(pEnd->z) - Addr(pStart->z) + 1;      sqliteVdbeChangeP3(v, addr, pStart->z, n);    }    sqliteVdbeAddOp(v, OP_MakeRecord, 5, 0);    sqliteVdbeAddOp(v, OP_PutIntKey, 0, 0);    if( pTable ){      sqliteVdbeAddOp(v, OP_Integer, pTab->iDb, 0);      sqliteVdbeOp3(v, OP_OpenRead, 2, pTab->tnum, pTab->zName, 0);      lbl2 = sqliteVdbeMakeLabel(v);      sqliteVdbeAddOp(v, OP_Rewind, 2, lbl2);      lbl1 = sqliteVdbeAddOp(v, OP_Recno, 2, 0);      for(i=0; i<pIndex->nColumn; i++){        int iCol = pIndex->aiColumn[i];        if( pTab->iPKey==iCol ){          sqliteVdbeAddOp(v, OP_Dup, i, 0);        }else{          sqliteVdbeAddOp(v, OP_Column, 2, iCol);        }      }      sqliteVdbeAddOp(v, OP_MakeIdxKey, pIndex->nColumn, 0);      if( db->file_format>=4 ) sqliteAddIdxKeyType(v, pIndex);      sqliteVdbeOp3(v, OP_IdxPut, 1, pIndex->onError!=OE_None,                      "indexed columns are not unique", P3_STATIC);      sqliteVdbeAddOp(v, OP_Next, 2, lbl1);      sqliteVdbeResolveLabel(v, lbl2);      sqliteVdbeAddOp(v, OP_Close, 2, 0);      sqliteVdbeAddOp(v, OP_Close, 1, 0);    }    if( pTable!=0 ){      if( !isTemp ){        sqliteChangeCookie(db, v);      }      sqliteVdbeAddOp(v, OP_Close, 0, 0);      sqliteEndWriteOperation(pParse);    }  }  /* Clean up before exiting */exit_create_index:  sqliteIdListDelete(pList);  sqliteSrcListDelete(pTable);  sqliteFree(zName);  return;}/*** This routine will drop an existing named index.  This routine** implements the DROP INDEX statement.*/void sqliteDropIndex(Parse *pParse, SrcList *pName){  Index *pIndex;  Vdbe *v;  sqlite *db = pParse->db;  if( pParse->nErr || sqlite_malloc_failed ) return;  assert( pName->nSrc==1 );  pIndex = sqliteFindIndex(db, pName->a[0].zName, pName->a[0].zDatabase);  if( pIndex==0 ){    sqliteErrorMsg(pParse, "no such index: %S", pName, 0);    goto exit_drop_index;  }  if( pIndex->autoIndex ){    sqliteErrorMsg(pParse, "index associated with UNIQUE "      "or PRIMARY KEY constraint cannot be dropped", 0);    goto exit_drop_index;  }  if( pIndex->iDb>1 ){    sqliteErrorMsg(pParse, "cannot alter schema of attached "       "databases", 0);    goto exit_drop_index;  }#ifndef SQLITE_OMIT_AUTHORIZATION  {    int code = SQLITE_DROP_INDEX;    Table *pTab = pIndex->pTable;    const char *zDb = db->aDb[pIndex->iDb].zName;    const char *zTab = SCHEMA_TABLE(pIndex->iDb);    if( sqliteAuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){      goto exit_drop_index;    }    if( pIndex->iDb ) code = SQLITE_DROP_TEMP_INDEX;    if( sqliteAuthCheck(pParse, code, pIndex->zName, pTab->zName, zDb) ){      goto exit_drop_index;    }  }#endif  /* Generate code to remove the index and from the master table */  v = sqliteGetVdbe(pParse);  if( v ){    static VdbeOpList dropIndex[] = {      { OP_Rewind,     0, ADDR(9), 0},       { OP_String,     0, 0,       0}, /* 1 */      { OP_MemStore,   1, 1,       0},      { OP_MemLoad,    1, 0,       0}, /* 3 */      { OP_Column,     0, 1,       0},      { OP_Eq,         0, ADDR(8), 0},      { OP_Next,       0, ADDR(3), 0},      { OP_Goto,       0, ADDR(9), 0},      { OP_Delete,     0, 0,       0}, /* 8 */    };    int base;    sqliteBeginWriteOperation(pParse, 0, pIndex->iDb);    sqliteOpenMasterTable(v, pIndex->iDb);    base = sqliteVdbeAddOpList(v, ArraySize(dropIndex), dropIndex);    sqliteVdbeChangeP3(v, base+1, pIndex->zName, 0);    if( pIndex->iDb==0 ){      sqliteChangeCookie(db, v);    }    sqliteVdbeAddOp(v, OP_Close, 0, 0);    sqliteVdbeAddOp(v, OP_Destroy, pIndex->tnum, pIndex->iDb);    sqliteEndWriteOperation(pParse);  }  /* Delete the in-memory description of this index.  */  if( !pParse->explain ){    sqliteUnlinkAndDeleteIndex(db, pIndex);    db->flags |= SQLITE_InternChanges;  }exit_drop_index:  sqliteSrcListDelete(pName);}/*** Append a new element to the given IdList.  Create a new IdList if** need be.**** A new IdList is returned, or NULL if malloc() fails.*/IdList *sqliteIdListAppend(IdList *pList, Token *pToken){  if( pList==0 ){    pList = sqliteMalloc( sizeof(IdList) );    if( pList==0 ) return 0;    pList->nAlloc = 0;  }  if( pList->nId>=pList->nAlloc ){    struct IdList_item *a;    pList->nAlloc = pList->nAlloc*2 + 5;    a = sqliteRealloc(pList->a, pList->nAlloc*sizeof(pList->a[0]) );    if( a==0 ){      sqliteIdListDelete(pList);      return 0;    }    pList->a = a;  }  memset(&pList->a[pList->nId], 0, sizeof(pList->a[0]));  if( pToken ){    char **pz = &pList->a[pList->nId].zName;    sqliteSetNString(pz, pToken->z, pToken->n, 0);    if( *pz==0 ){      sqliteIdListDelete(pList);      return 0;    }else{      sqliteDequote(*pz);    }  }  pList->nId++;  return pList;}/*** Append a new table name to the given SrcList.  Create a new SrcList if** need be.  A new entry is created in the SrcList even if pToken is NULL.**** A new SrcList is returned, or NULL if malloc() fails.**** If pDatabase is not null, it means that the table has an optional** database name prefix.  Like this:  "database.table".  The pDatabase** points to the table name and the pTable points to the database name.** The SrcList.a[].zName field is filled with the table name which might** come from pTable (if pDatabase is NULL) or from pDatabase.  ** SrcList.a[].zDatabase is filled with the database name from pTable,** or with NULL if no database is specified.**** In other words, if call like this:****         sqliteSrcListAppend(A,B,0);**** Then B is a table name and the database name is unspecified.  If called** like this:****         sqliteSrcListAppend(A,B,C);**** Then C is the table name and B is the database name.*/SrcList *sqliteSrcListAppend(SrcList *pList, Token *pTable, Token *pDatabase){  if( pList==0 ){    pList = sqliteMalloc( sizeof(SrcList) );    if( pList==0 ) return 0;    pList->nAlloc = 1;  }  if( pList->nSrc>=pList->nAlloc ){    SrcList *pNew;    pList->nAlloc *= 2;    pNew = sqliteRealloc(pList,               sizeof(*pList) + (pList->nAlloc-1)*sizeof(pList->a[0]) );    if( pNew==0 ){      sqliteSrcListDelete(pList);      return 0;    }    pList = pNew;  }  memset(&pList->a[pList->nSrc], 0, sizeof(pList->a[0]));  if( pDatabase && pDatabase->z==0 ){    pDatabase = 0;  }  if( pDatabase && pTable ){    Token *pTemp = pDatabase;    pDatabase = pTable;    pTable = pTemp;  }  if( pTable ){    char **pz = &pList->a[pList->nSrc].zName;    sqliteSetNString(pz, pTable->z, pTable->n, 0);    if( *pz==0 ){      sqliteSrcListDelete(pList);      return 0;    }else{      sqliteDequote(*pz);    }  }  if( pDatabase ){    char **pz = &pList->a[pList->nSrc].zDatabase;    sqliteSetNString(pz, pDatabase->z, pDatabase->n, 0);    if( *pz==0 ){      sqliteSrcListDelete(pList);      return 0;    }else{      sqliteDequote(*pz);    }  }  pList->a[pList->nSrc].iCursor = -1;  pList->nSrc++;  return pList;}/*** Assign cursors to all tables in a SrcList*/void sqliteSrcListAssignCursors(Parse *pParse, SrcList *pList){  int i;  for(i=0; i<pList->nSrc; i++){    if( pList->a[i].iCursor<0 ){      pList->a[i].iCursor = pParse->nTab++;    }  }}/*** Add an alias to the last identifier on the given identifier list.*/void sqliteSrcListAddAlias(SrcList *pList, Token *pToken){  if( pList && pList->nSrc>0 ){    int i = pList->nSrc - 1;    sqliteSetNString(&pList->a[i].zAlias, pToken->z, pToken->n, 0);    sqliteDequote(pList->a[i].zAlias);  }}/*** Delete an IdList.*/void sqliteIdListDelete(IdList *pList){  int i;  if( pList==0 ) return;  for(i=0; i<pList->nId; i++){    sqliteFree(pList->a[i].zName);  }  sqliteFree(pList->a);  sqliteFree(pList);}/*** Return the index in pList of the identifier named zId.  Return -1** if not found.*/int sqliteIdListIndex(IdList *pList, const char *zName){  int i;  if( pList==0 ) return -1;  for(i=0; i<pList->nId; i++){    if( sqliteStrICmp(pList->a[i].zName, zName)==0 ) return i;  }  return -1;}/*** Delete an entire SrcList including all its substructure.*/void sqliteSrcListDelete(SrcList *pList){  int i;  if( pList==0 ) return;  for(i=0; i<pList->nSrc; i++){    sqliteFree(pList->a[i].zDatabase);    sqliteFree(pList->a[i].zName);    sqliteFree(pList->a[i].zAlias);    if( pList->a[i].pTab && pList->a[i].pTab->isTransient ){      sqliteDeleteTable(0, pList->a[i].pTab);    }    sqliteSelectDelete(pList->a[i].pSelect);    sqliteExprDelete(pList->a[i].pOn);    sqliteIdListDelete(pList->a[i].pUsing);  }  sqliteFree(pList);}/*** Begin a transaction*/void sqliteBeginTransaction(Parse *pParse, int onError){  sqlite *db;  if( pParse==0 || (db=pParse->db)==0 || db->aDb[0].pBt==0 ) return;  if( pParse->nErr || sqlite_malloc_failed ) return;  if( sqliteAuthCheck(pParse, SQLITE_TRANSACTION, "BEGIN", 0, 0) ) return;  if( db->flags & SQLITE_InTrans ){    sqliteErrorMsg(pParse, "cannot start a transaction within a transaction");    return;  }  sqliteBeginWriteOperation(pParse, 0, 0);  if( !pParse->explain ){    db->flags |= SQLITE_InTrans;    db->onError = onError;  }}/*** Commit a transaction*/void sqliteCommitTransaction(Parse *pParse){  sqlite *db;  if( pParse==0 || (db=pParse->db)==0 || db->aDb[0].pBt==0 ) return;  if( pParse->nErr || sqlite_malloc_failed ) return;  if( sqliteAuthCheck(pParse, SQLITE_TRANSACTION, "COMMIT", 0, 0) ) return;  if( (db->flags & SQLITE_InTrans)==0 ){    sqliteErrorMsg(pParse, "cannot commit - no transaction is active");    return;  }  if( !pParse->explain ){    db->flags &= ~SQLITE_InTrans;  }  sqliteEndWriteOperation(pParse);  if( !pParse->explain ){    db->onError = OE_Default;  }}/*** Rollback a transaction*/void sqliteRollbackTransaction(Parse *pParse){  sqlite *db;  Vdbe *v;  if( pParse==0 || (db=pParse->db)==0 || db->aDb[0].pBt==0 ) return;  if( pParse->nErr || sqlite_malloc_failed ) return;  if( sqliteAuthCheck(pParse, SQLITE_TRANSACTION, "ROLLBACK", 0, 0) ) return;  if( (db->flags & SQLITE_InTrans)==0 ){    sqliteErrorMsg(pParse, "cannot rollback - no transaction is active");    return;   }  v = sqliteGetVdbe(pParse);  if( v ){    sqliteVdbeAddOp(v, OP_Rollback, 0, 0);  }  if( !pParse->explain ){    db->flags &= ~SQLITE_InTrans;    db->onError = OE_Default;  }}/*** Generate VDBE code that will verify the schema cookie for all** named database files.*/void sqliteCodeVerifySchema(Parse *pParse, int iDb){  sqlite *db = pParse->db;  Vdbe *v = sqliteGetVdbe(pParse);  assert( iDb>=0 && iDb<db->nDb );  assert( db->aDb[iDb].pBt!=0 );  if( iDb!=1 && !DbHasProperty(db, iDb, DB_Cookie) ){    sqliteVdbeAddOp(v, OP_VerifyCookie, iDb, db->aDb[iDb].schema_cookie);    DbSetProperty(db, iDb, DB_Cookie);  }}/*** Generate VDBE code that prepares for doing an operation that** might change the database.**** This routine starts a new transaction if we are not already within** a transaction.  If we are already within a transaction, then a checkpoint** is set if the setCheckpoint parameter is true.  A checkpoint should** be set for operations that might fail (due to a constraint) part of** the way through and which will need to undo some writes without having to** rollback the whole transaction.  For operations where all constraints** can be checked before any changes are made to the database, it is never** necessary to undo a write and the checkpoint should not be set.**** Only database iDb and the temp database are made writable by this call.**