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1669 lines (1536 loc) · 52.6 KB
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/*
** 2005 February 15
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that used to generate VDBE code
** that implements the ALTER TABLE command.
*/
#include "sqliteInt.h"
/*
** The code in this file only exists if we are not omitting the
** ALTER TABLE logic from the build.
*/
#ifndef SQLITE_OMIT_ALTERTABLE
/*
** 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 isAlterableTable(Parse *pParse, Table *pTab){
if( 0==sqlite3StrNICmp(pTab->zName, "sqlite_", 7)
#ifndef SQLITE_OMIT_VIRTUALTABLE
|| ( (pTab->tabFlags & TF_Shadow)
&& (pParse->db->flags & SQLITE_Defensive)
&& pParse->db->nVdbeExec==0
)
#endif
){
sqlite3ErrorMsg(pParse, "table %s may not be altered", pTab->zName);
return 1;
}
return 0;
}
/*
** Generate code to verify that the schemas of database zDb and, if
** bTemp is not true, database "temp", can still be parsed. This is
** called at the end of the generation of an ALTER TABLE ... RENAME ...
** statement to ensure that the operation has not rendered any schema
** objects unusable.
*/
static void renameTestSchema(Parse *pParse, const char *zDb, int bTemp){
sqlite3NestedParse(pParse,
"SELECT 1 "
"FROM \"%w\".%s "
"WHERE name NOT LIKE 'sqliteX_%%' ESCAPE 'X'"
" AND sql NOT LIKE 'create virtual%%'"
" AND sqlite_rename_test(%Q, sql, type, name, %d)=NULL ",
zDb, MASTER_NAME,
zDb, bTemp
);
if( bTemp==0 ){
sqlite3NestedParse(pParse,
"SELECT 1 "
"FROM temp.%s "
"WHERE name NOT LIKE 'sqliteX_%%' ESCAPE 'X'"
" AND sql NOT LIKE 'create virtual%%'"
" AND sqlite_rename_test(%Q, sql, type, name, 1)=NULL ",
MASTER_NAME, zDb
);
}
}
/*
** Generate code to reload the schema for database iDb. And, if iDb!=1, for
** the temp database as well.
*/
static void renameReloadSchema(Parse *pParse, int iDb){
Vdbe *v = pParse->pVdbe;
if( v ){
sqlite3ChangeCookie(pParse, iDb);
sqlite3VdbeAddParseSchemaOp(pParse->pVdbe, iDb, 0);
if( iDb!=1 ) sqlite3VdbeAddParseSchemaOp(pParse->pVdbe, 1, 0);
}
}
/*
** Generate code to implement the "ALTER TABLE xxx RENAME TO yyy"
** command.
*/
void sqlite3AlterRenameTable(
Parse *pParse, /* Parser context. */
SrcList *pSrc, /* The table to rename. */
Token *pName /* The new table name. */
){
int iDb; /* Database that contains the table */
char *zDb; /* Name of database iDb */
Table *pTab; /* Table being renamed */
char *zName = 0; /* NULL-terminated version of pName */
sqlite3 *db = pParse->db; /* Database connection */
int nTabName; /* Number of UTF-8 characters in zTabName */
const char *zTabName; /* Original name of the table */
Vdbe *v;
VTable *pVTab = 0; /* Non-zero if this is a v-tab with an xRename() */
u32 savedDbFlags; /* Saved value of db->mDbFlags */
savedDbFlags = db->mDbFlags;
if( NEVER(db->mallocFailed) ) goto exit_rename_table;
assert( pSrc->nSrc==1 );
assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
if( !pTab ) goto exit_rename_table;
iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
zDb = db->aDb[iDb].zDbSName;
db->mDbFlags |= DBFLAG_PreferBuiltin;
/* Get a NULL terminated version of the new table name. */
zName = sqlite3NameFromToken(db, pName);
if( !zName ) goto exit_rename_table;
/* Check that a table or index named 'zName' does not already exist
** in database iDb. If so, this is an error.
*/
if( sqlite3FindTable(db, zName, zDb) || sqlite3FindIndex(db, zName, zDb) ){
sqlite3ErrorMsg(pParse,
"there is already another table or index with this name: %s", zName);
goto exit_rename_table;
}
/* Make sure it is not a system table being altered, or a reserved name
** that the table is being renamed to.
*/
if( SQLITE_OK!=isAlterableTable(pParse, pTab) ){
goto exit_rename_table;
}
if( SQLITE_OK!=sqlite3CheckObjectName(pParse,zName,"table",zName) ){
goto exit_rename_table;
}
#ifndef SQLITE_OMIT_VIEW
if( pTab->pSelect ){
sqlite3ErrorMsg(pParse, "view %s may not be altered", pTab->zName);
goto exit_rename_table;
}
#endif
#ifndef SQLITE_OMIT_AUTHORIZATION
/* Invoke the authorization callback. */
if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
goto exit_rename_table;
}
#endif
#ifndef SQLITE_OMIT_VIRTUALTABLE
if( sqlite3ViewGetColumnNames(pParse, pTab) ){
goto exit_rename_table;
}
if( IsVirtual(pTab) ){
pVTab = sqlite3GetVTable(db, pTab);
if( pVTab->pVtab->pModule->xRename==0 ){
pVTab = 0;
}
}
#endif
/* Begin a transaction for database iDb. Then modify the schema cookie
** (since the ALTER TABLE modifies the schema). Call sqlite3MayAbort(),
** as the scalar functions (e.g. sqlite_rename_table()) invoked by the
** nested SQL may raise an exception. */
v = sqlite3GetVdbe(pParse);
if( v==0 ){
goto exit_rename_table;
}
sqlite3MayAbort(pParse);
/* figure out how many UTF-8 characters are in zName */
zTabName = pTab->zName;
nTabName = sqlite3Utf8CharLen(zTabName, -1);
/* Rewrite all CREATE TABLE, INDEX, TRIGGER or VIEW statements in
** the schema to use the new table name. */
sqlite3NestedParse(pParse,
"UPDATE \"%w\".%s SET "
"sql = sqlite_rename_table(%Q, type, name, sql, %Q, %Q, %d) "
"WHERE (type!='index' OR tbl_name=%Q COLLATE nocase)"
"AND name NOT LIKE 'sqliteX_%%' ESCAPE 'X'"
, zDb, MASTER_NAME, zDb, zTabName, zName, (iDb==1), zTabName
);
/* Update the tbl_name and name columns of the sqlite_master table
** as required. */
sqlite3NestedParse(pParse,
"UPDATE %Q.%s SET "
"tbl_name = %Q, "
"name = CASE "
"WHEN type='table' THEN %Q "
"WHEN name LIKE 'sqliteX_autoindex%%' ESCAPE 'X' "
" AND type='index' THEN "
"'sqlite_autoindex_' || %Q || substr(name,%d+18) "
"ELSE name END "
"WHERE tbl_name=%Q COLLATE nocase AND "
"(type='table' OR type='index' OR type='trigger');",
zDb, MASTER_NAME,
zName, zName, zName,
nTabName, zTabName
);
#ifndef SQLITE_OMIT_AUTOINCREMENT
/* If the sqlite_sequence table exists in this database, then update
** it with the new table name.
*/
if( sqlite3FindTable(db, "sqlite_sequence", zDb) ){
sqlite3NestedParse(pParse,
"UPDATE \"%w\".sqlite_sequence set name = %Q WHERE name = %Q",
zDb, zName, pTab->zName);
}
#endif
/* If the table being renamed is not itself part of the temp database,
** edit view and trigger definitions within the temp database
** as required. */
if( iDb!=1 ){
sqlite3NestedParse(pParse,
"UPDATE sqlite_temp_master SET "
"sql = sqlite_rename_table(%Q, type, name, sql, %Q, %Q, 1), "
"tbl_name = "
"CASE WHEN tbl_name=%Q COLLATE nocase AND "
" sqlite_rename_test(%Q, sql, type, name, 1) "
"THEN %Q ELSE tbl_name END "
"WHERE type IN ('view', 'trigger')"
, zDb, zTabName, zName, zTabName, zDb, zName);
}
/* 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
if( pVTab ){
int i = ++pParse->nMem;
sqlite3VdbeLoadString(v, i, zName);
sqlite3VdbeAddOp4(v, OP_VRename, i, 0, 0,(const char*)pVTab, P4_VTAB);
}
#endif
renameReloadSchema(pParse, iDb);
renameTestSchema(pParse, zDb, iDb==1);
exit_rename_table:
sqlite3SrcListDelete(db, pSrc);
sqlite3DbFree(db, zName);
db->mDbFlags = savedDbFlags;
}
/*
** This function is called after an "ALTER TABLE ... ADD" statement
** has been parsed. Argument pColDef contains the text of the new
** column definition.
**
** The Table structure pParse->pNewTable was extended to include
** the new column during parsing.
*/
void sqlite3AlterFinishAddColumn(Parse *pParse, Token *pColDef){
Table *pNew; /* Copy of pParse->pNewTable */
Table *pTab; /* Table being altered */
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; /* The prepared statement under construction */
int r1; /* Temporary registers */
db = pParse->db;
if( pParse->nErr || db->mallocFailed ) return;
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 */
pCol = &pNew->aCol[pNew->nCol-1];
pDflt = pCol->pDflt;
pTab = sqlite3FindTable(db, zTab, zDb);
assert( pTab );
#ifndef SQLITE_OMIT_AUTHORIZATION
/* Invoke the authorization callback. */
if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
return;
}
#endif
/* If the default value for the new column was specified with a
** literal NULL, then set pDflt to 0. This simplifies checking
** for an SQL NULL default below.
*/
assert( pDflt==0 || pDflt->op==TK_SPAN );
if( pDflt && pDflt->pLeft->op==TK_NULL ){
pDflt = 0;
}
/* Check that the new column is not specified as PRIMARY KEY or UNIQUE.
** If there is a NOT NULL constraint, then the default value for the
** column must not be NULL.
*/
if( pCol->colFlags & COLFLAG_PRIMKEY ){
sqlite3ErrorMsg(pParse, "Cannot add a PRIMARY KEY column");
return;
}
if( pNew->pIndex ){
sqlite3ErrorMsg(pParse, "Cannot add a UNIQUE column");
return;
}
if( (db->flags&SQLITE_ForeignKeys) && pNew->pFKey && pDflt ){
sqlite3ErrorMsg(pParse,
"Cannot add a REFERENCES column with non-NULL default value");
return;
}
if( pCol->notNull && !pDflt ){
sqlite3ErrorMsg(pParse,
"Cannot add a NOT NULL column with default value NULL");
return;
}
/* Ensure the default expression is something that sqlite3ValueFromExpr()
** can handle (i.e. not CURRENT_TIME etc.)
*/
if( pDflt ){
sqlite3_value *pVal = 0;
int rc;
rc = sqlite3ValueFromExpr(db, pDflt, SQLITE_UTF8, SQLITE_AFF_BLOB, &pVal);
assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
if( rc!=SQLITE_OK ){
assert( db->mallocFailed == 1 );
return;
}
if( !pVal ){
sqlite3ErrorMsg(pParse, "Cannot add a column with non-constant default");
return;
}
sqlite3ValueFree(pVal);
}
/* Modify the CREATE TABLE statement. */
zCol = sqlite3DbStrNDup(db, (char*)pColDef->z, pColDef->n);
if( zCol ){
char *zEnd = &zCol[pColDef->n-1];
u32 savedDbFlags = db->mDbFlags;
while( zEnd>zCol && (*zEnd==';' || sqlite3Isspace(*zEnd)) ){
*zEnd-- = '\0';
}
db->mDbFlags |= DBFLAG_PreferBuiltin;
sqlite3NestedParse(pParse,
"UPDATE \"%w\".%s SET "
"sql = substr(sql,1,%d) || ', ' || %Q || substr(sql,%d) "
"WHERE type = 'table' AND name = %Q",
zDb, MASTER_NAME, pNew->addColOffset, zCol, pNew->addColOffset+1,
zTab
);
sqlite3DbFree(db, zCol);
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.
*/
v = sqlite3GetVdbe(pParse);
if( v ){
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 table definition */
renameReloadSchema(pParse, iDb);
}
/*
** 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.
**
** This routine makes a (partial) copy of the Table structure
** for the table being altered and sets Parse.pNewTable to point
** to it. Routines called by the parser as the column definition
** is parsed (i.e. sqlite3AddColumn()) add the new Column data to
** the copy. The copy of the Table structure is deleted by tokenize.c
** after parsing is finished.
**
** Routine sqlite3AlterFinishAddColumn() will be called to complete
** coding the "ALTER TABLE ... ADD" statement.
*/
void sqlite3AlterBeginAddColumn(Parse *pParse, SrcList *pSrc){
Table *pNew;
Table *pTab;
int iDb;
int i;
int nAlloc;
sqlite3 *db = pParse->db;
/* Look up the table being altered. */
assert( pParse->pNewTable==0 );
assert( sqlite3BtreeHoldsAllMutexes(db) );
if( db->mallocFailed ) goto exit_begin_add_column;
pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
if( !pTab ) goto exit_begin_add_column;
#ifndef SQLITE_OMIT_VIRTUALTABLE
if( IsVirtual(pTab) ){
sqlite3ErrorMsg(pParse, "virtual tables may not be altered");
goto exit_begin_add_column;
}
#endif
/* Make sure this is not an attempt to ALTER a view. */
if( pTab->pSelect ){
sqlite3ErrorMsg(pParse, "Cannot add a column to a view");
goto exit_begin_add_column;
}
if( SQLITE_OK!=isAlterableTable(pParse, pTab) ){
goto exit_begin_add_column;
}
sqlite3MayAbort(pParse);
assert( pTab->addColOffset>0 );
iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
/* Put a copy of the Table struct in Parse.pNewTable for the
** sqlite3AddColumn() function and friends to modify. But modify
** the name by adding an "sqlite_altertab_" prefix. By adding this
** prefix, we insure that the name will not collide with an existing
** table because user table are not allowed to have the "sqlite_"
** prefix on their name.
*/
pNew = (Table*)sqlite3DbMallocZero(db, sizeof(Table));
if( !pNew ) goto exit_begin_add_column;
pParse->pNewTable = pNew;
pNew->nTabRef = 1;
pNew->nCol = pTab->nCol;
assert( pNew->nCol>0 );
nAlloc = (((pNew->nCol-1)/8)*8)+8;
assert( nAlloc>=pNew->nCol && nAlloc%8==0 && nAlloc-pNew->nCol<8 );
pNew->aCol = (Column*)sqlite3DbMallocZero(db, sizeof(Column)*nAlloc);
pNew->zName = sqlite3MPrintf(db, "sqlite_altertab_%s", pTab->zName);
if( !pNew->aCol || !pNew->zName ){
assert( db->mallocFailed );
goto exit_begin_add_column;
}
memcpy(pNew->aCol, pTab->aCol, sizeof(Column)*pNew->nCol);
for(i=0; i<pNew->nCol; i++){
Column *pCol = &pNew->aCol[i];
pCol->zName = sqlite3DbStrDup(db, pCol->zName);
pCol->zColl = 0;
pCol->pDflt = 0;
}
pNew->pSchema = db->aDb[iDb].pSchema;
pNew->addColOffset = pTab->addColOffset;
pNew->nTabRef = 1;
exit_begin_add_column:
sqlite3SrcListDelete(db, pSrc);
return;
}
/*
** Parameter pTab is the subject of an ALTER TABLE ... RENAME COLUMN
** command. This function checks if the table is a view or virtual
** table (columns of views or virtual tables may not be renamed). If so,
** it loads an error message into pParse and returns non-zero.
**
** Or, if pTab is not a view or virtual table, zero is returned.
*/
#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)
static int isRealTable(Parse *pParse, Table *pTab){
const char *zType = 0;
#ifndef SQLITE_OMIT_VIEW
if( pTab->pSelect ){
zType = "view";
}
#endif
#ifndef SQLITE_OMIT_VIRTUALTABLE
if( IsVirtual(pTab) ){
zType = "virtual table";
}
#endif
if( zType ){
sqlite3ErrorMsg(
pParse, "cannot rename columns of %s \"%s\"", zType, pTab->zName
);
return 1;
}
return 0;
}
#else /* !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE) */
# define isRealTable(x,y) (0)
#endif
/*
** Handles the following parser reduction:
**
** cmd ::= ALTER TABLE pSrc RENAME COLUMN pOld TO pNew
*/
void sqlite3AlterRenameColumn(
Parse *pParse, /* Parsing context */
SrcList *pSrc, /* Table being altered. pSrc->nSrc==1 */
Token *pOld, /* Name of column being changed */
Token *pNew /* New column name */
){
sqlite3 *db = pParse->db; /* Database connection */
Table *pTab; /* Table being updated */
int iCol; /* Index of column being renamed */
char *zOld = 0; /* Old column name */
char *zNew = 0; /* New column name */
const char *zDb; /* Name of schema containing the table */
int iSchema; /* Index of the schema */
int bQuote; /* True to quote the new name */
/* Locate the table to be altered */
pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
if( !pTab ) goto exit_rename_column;
/* Cannot alter a system table */
if( SQLITE_OK!=isAlterableTable(pParse, pTab) ) goto exit_rename_column;
if( SQLITE_OK!=isRealTable(pParse, pTab) ) goto exit_rename_column;
/* Which schema holds the table to be altered */
iSchema = sqlite3SchemaToIndex(db, pTab->pSchema);
assert( iSchema>=0 );
zDb = db->aDb[iSchema].zDbSName;
#ifndef SQLITE_OMIT_AUTHORIZATION
/* Invoke the authorization callback. */
if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
goto exit_rename_column;
}
#endif
/* Make sure the old name really is a column name in the table to be
** altered. Set iCol to be the index of the column being renamed */
zOld = sqlite3NameFromToken(db, pOld);
if( !zOld ) goto exit_rename_column;
for(iCol=0; iCol<pTab->nCol; iCol++){
if( 0==sqlite3StrICmp(pTab->aCol[iCol].zName, zOld) ) break;
}
if( iCol==pTab->nCol ){
sqlite3ErrorMsg(pParse, "no such column: \"%s\"", zOld);
goto exit_rename_column;
}
/* Do the rename operation using a recursive UPDATE statement that
** uses the sqlite_rename_column() SQL function to compute the new
** CREATE statement text for the sqlite_master table.
*/
sqlite3MayAbort(pParse);
zNew = sqlite3NameFromToken(db, pNew);
if( !zNew ) goto exit_rename_column;
assert( pNew->n>0 );
bQuote = sqlite3Isquote(pNew->z[0]);
sqlite3NestedParse(pParse,
"UPDATE \"%w\".%s SET "
"sql = sqlite_rename_column(sql, type, name, %Q, %Q, %d, %Q, %d, %d) "
"WHERE name NOT LIKE 'sqliteX_%%' ESCAPE 'X' "
" AND (type != 'index' OR tbl_name = %Q)"
" AND sql NOT LIKE 'create virtual%%'",
zDb, MASTER_NAME,
zDb, pTab->zName, iCol, zNew, bQuote, iSchema==1,
pTab->zName
);
sqlite3NestedParse(pParse,
"UPDATE temp.%s SET "
"sql = sqlite_rename_column(sql, type, name, %Q, %Q, %d, %Q, %d, 1) "
"WHERE type IN ('trigger', 'view')",
MASTER_NAME,
zDb, pTab->zName, iCol, zNew, bQuote
);
/* Drop and reload the database schema. */
renameReloadSchema(pParse, iSchema);
renameTestSchema(pParse, zDb, iSchema==1);
exit_rename_column:
sqlite3SrcListDelete(db, pSrc);
sqlite3DbFree(db, zOld);
sqlite3DbFree(db, zNew);
return;
}
/*
** Each RenameToken object maps an element of the parse tree into
** the token that generated that element. The parse tree element
** might be one of:
**
** * A pointer to an Expr that represents an ID
** * The name of a table column in Column.zName
**
** A list of RenameToken objects can be constructed during parsing.
** Each new object is created by sqlite3RenameTokenMap().
** As the parse tree is transformed, the sqlite3RenameTokenRemap()
** routine is used to keep the mapping current.
**
** After the parse finishes, renameTokenFind() routine can be used
** to look up the actual token value that created some element in
** the parse tree.
*/
struct RenameToken {
void *p; /* Parse tree element created by token t */
Token t; /* The token that created parse tree element p */
RenameToken *pNext; /* Next is a list of all RenameToken objects */
};
/*
** The context of an ALTER TABLE RENAME COLUMN operation that gets passed
** down into the Walker.
*/
typedef struct RenameCtx RenameCtx;
struct RenameCtx {
RenameToken *pList; /* List of tokens to overwrite */
int nList; /* Number of tokens in pList */
int iCol; /* Index of column being renamed */
Table *pTab; /* Table being ALTERed */
const char *zOld; /* Old column name */
};
#ifdef SQLITE_DEBUG
/*
** This function is only for debugging. It performs two tasks:
**
** 1. Checks that pointer pPtr does not already appear in the
** rename-token list.
**
** 2. Dereferences each pointer in the rename-token list.
**
** The second is most effective when debugging under valgrind or
** address-sanitizer or similar. If any of these pointers no longer
** point to valid objects, an exception is raised by the memory-checking
** tool.
**
** The point of this is to prevent comparisons of invalid pointer values.
** Even though this always seems to work, it is undefined according to the
** C standard. Example of undefined comparison:
**
** sqlite3_free(x);
** if( x==y ) ...
**
** Technically, as x no longer points into a valid object or to the byte
** following a valid object, it may not be used in comparison operations.
*/
static void renameTokenCheckAll(Parse *pParse, void *pPtr){
if( pParse->nErr==0 && pParse->db->mallocFailed==0 ){
RenameToken *p;
u8 i = 0;
for(p=pParse->pRename; p; p=p->pNext){
if( p->p ){
assert( p->p!=pPtr );
i += *(u8*)(p->p);
}
}
}
}
#else
# define renameTokenCheckAll(x,y)
#endif
/*
** Remember that the parser tree element pPtr was created using
** the token pToken.
**
** In other words, construct a new RenameToken object and add it
** to the list of RenameToken objects currently being built up
** in pParse->pRename.
**
** The pPtr argument is returned so that this routine can be used
** with tail recursion in tokenExpr() routine, for a small performance
** improvement.
*/
void *sqlite3RenameTokenMap(Parse *pParse, void *pPtr, Token *pToken){
RenameToken *pNew;
assert( pPtr || pParse->db->mallocFailed );
renameTokenCheckAll(pParse, pPtr);
pNew = sqlite3DbMallocZero(pParse->db, sizeof(RenameToken));
if( pNew ){
pNew->p = pPtr;
pNew->t = *pToken;
pNew->pNext = pParse->pRename;
pParse->pRename = pNew;
}
return pPtr;
}
/*
** It is assumed that there is already a RenameToken object associated
** with parse tree element pFrom. This function remaps the associated token
** to parse tree element pTo.
*/
void sqlite3RenameTokenRemap(Parse *pParse, void *pTo, void *pFrom){
RenameToken *p;
renameTokenCheckAll(pParse, pTo);
for(p=pParse->pRename; p; p=p->pNext){
if( p->p==pFrom ){
p->p = pTo;
break;
}
}
}
/*
** Walker callback used by sqlite3RenameExprUnmap().
*/
static int renameUnmapExprCb(Walker *pWalker, Expr *pExpr){
Parse *pParse = pWalker->pParse;
sqlite3RenameTokenRemap(pParse, 0, (void*)pExpr);
return WRC_Continue;
}
/*
** Walker callback used by sqlite3RenameExprUnmap().
*/
static int renameUnmapSelectCb(Walker *pWalker, Select *p){
Parse *pParse = pWalker->pParse;
int i;
if( ALWAYS(p->pEList) ){
ExprList *pList = p->pEList;
for(i=0; i<pList->nExpr; i++){
if( pList->a[i].zName ){
sqlite3RenameTokenRemap(pParse, 0, (void*)pList->a[i].zName);
}
}
}
if( ALWAYS(p->pSrc) ){ /* Every Select as a SrcList, even if it is empty */
SrcList *pSrc = p->pSrc;
for(i=0; i<pSrc->nSrc; i++){
sqlite3RenameTokenRemap(pParse, 0, (void*)pSrc->a[i].zName);
}
}
return WRC_Continue;
}
/*
** Remove all nodes that are part of expression pExpr from the rename list.
*/
void sqlite3RenameExprUnmap(Parse *pParse, Expr *pExpr){
Walker sWalker;
memset(&sWalker, 0, sizeof(Walker));
sWalker.pParse = pParse;
sWalker.xExprCallback = renameUnmapExprCb;
sWalker.xSelectCallback = renameUnmapSelectCb;
sqlite3WalkExpr(&sWalker, pExpr);
}
/*
** Remove all nodes that are part of expression-list pEList from the
** rename list.
*/
void sqlite3RenameExprlistUnmap(Parse *pParse, ExprList *pEList){
if( pEList ){
int i;
Walker sWalker;
memset(&sWalker, 0, sizeof(Walker));
sWalker.pParse = pParse;
sWalker.xExprCallback = renameUnmapExprCb;
sqlite3WalkExprList(&sWalker, pEList);
for(i=0; i<pEList->nExpr; i++){
sqlite3RenameTokenRemap(pParse, 0, (void*)pEList->a[i].zName);
}
}
}
/*
** Free the list of RenameToken objects given in the second argument
*/
static void renameTokenFree(sqlite3 *db, RenameToken *pToken){
RenameToken *pNext;
RenameToken *p;
for(p=pToken; p; p=pNext){
pNext = p->pNext;
sqlite3DbFree(db, p);
}
}
/*
** Search the Parse object passed as the first argument for a RenameToken
** object associated with parse tree element pPtr. If found, remove it
** from the Parse object and add it to the list maintained by the
** RenameCtx object passed as the second argument.
*/
static void renameTokenFind(Parse *pParse, struct RenameCtx *pCtx, void *pPtr){
RenameToken **pp;
assert( pPtr!=0 );
for(pp=&pParse->pRename; (*pp); pp=&(*pp)->pNext){
if( (*pp)->p==pPtr ){
RenameToken *pToken = *pp;
*pp = pToken->pNext;
pToken->pNext = pCtx->pList;
pCtx->pList = pToken;
pCtx->nList++;
break;
}
}
}
/*
** Iterate through the Select objects that are part of WITH clauses attached
** to select statement pSelect.
*/
static void renameWalkWith(Walker *pWalker, Select *pSelect){
if( pSelect->pWith ){
int i;
for(i=0; i<pSelect->pWith->nCte; i++){
Select *p = pSelect->pWith->a[i].pSelect;
NameContext sNC;
memset(&sNC, 0, sizeof(sNC));
sNC.pParse = pWalker->pParse;
sqlite3SelectPrep(sNC.pParse, p, &sNC);
sqlite3WalkSelect(pWalker, p);
}
}
}
/*
** This is a Walker select callback. It does nothing. It is only required
** because without a dummy callback, sqlite3WalkExpr() and similar do not
** descend into sub-select statements.
*/
static int renameColumnSelectCb(Walker *pWalker, Select *p){
renameWalkWith(pWalker, p);
return WRC_Continue;
}
/*
** This is a Walker expression callback.
**
** For every TK_COLUMN node in the expression tree, search to see
** if the column being references is the column being renamed by an
** ALTER TABLE statement. If it is, then attach its associated
** RenameToken object to the list of RenameToken objects being
** constructed in RenameCtx object at pWalker->u.pRename.
*/
static int renameColumnExprCb(Walker *pWalker, Expr *pExpr){
RenameCtx *p = pWalker->u.pRename;
if( pExpr->op==TK_TRIGGER
&& pExpr->iColumn==p->iCol
&& pWalker->pParse->pTriggerTab==p->pTab
){
renameTokenFind(pWalker->pParse, p, (void*)pExpr);
}else if( pExpr->op==TK_COLUMN
&& pExpr->iColumn==p->iCol
&& p->pTab==pExpr->y.pTab
){
renameTokenFind(pWalker->pParse, p, (void*)pExpr);
}
return WRC_Continue;
}
/*
** The RenameCtx contains a list of tokens that reference a column that
** is being renamed by an ALTER TABLE statement. Return the "last"
** RenameToken in the RenameCtx and remove that RenameToken from the
** RenameContext. "Last" means the last RenameToken encountered when
** the input SQL is parsed from left to right. Repeated calls to this routine
** return all column name tokens in the order that they are encountered
** in the SQL statement.
*/
static RenameToken *renameColumnTokenNext(RenameCtx *pCtx){
RenameToken *pBest = pCtx->pList;
RenameToken *pToken;
RenameToken **pp;
for(pToken=pBest->pNext; pToken; pToken=pToken->pNext){
if( pToken->t.z>pBest->t.z ) pBest = pToken;
}
for(pp=&pCtx->pList; *pp!=pBest; pp=&(*pp)->pNext);
*pp = pBest->pNext;
return pBest;
}
/*
** An error occured while parsing or otherwise processing a database
** object (either pParse->pNewTable, pNewIndex or pNewTrigger) as part of an
** ALTER TABLE RENAME COLUMN program. The error message emitted by the
** sub-routine is currently stored in pParse->zErrMsg. This function
** adds context to the error message and then stores it in pCtx.
*/
static void renameColumnParseError(
sqlite3_context *pCtx,
int bPost,
sqlite3_value *pType,
sqlite3_value *pObject,
Parse *pParse
){
const char *zT = (const char*)sqlite3_value_text(pType);
const char *zN = (const char*)sqlite3_value_text(pObject);
char *zErr;
zErr = sqlite3_mprintf("error in %s %s%s: %s",
zT, zN, (bPost ? " after rename" : ""),
pParse->zErrMsg
);
sqlite3_result_error(pCtx, zErr, -1);
sqlite3_free(zErr);
}
/*
** For each name in the the expression-list pEList (i.e. each
** pEList->a[i].zName) that matches the string in zOld, extract the
** corresponding rename-token from Parse object pParse and add it
** to the RenameCtx pCtx.
*/
static void renameColumnElistNames(
Parse *pParse,
RenameCtx *pCtx,
ExprList *pEList,
const char *zOld
){
if( pEList ){
int i;
for(i=0; i<pEList->nExpr; i++){
char *zName = pEList->a[i].zName;
if( 0==sqlite3_stricmp(zName, zOld) ){
renameTokenFind(pParse, pCtx, (void*)zName);
}
}
}
}
/*
** For each name in the the id-list pIdList (i.e. each pIdList->a[i].zName)
** that matches the string in zOld, extract the corresponding rename-token
** from Parse object pParse and add it to the RenameCtx pCtx.
*/
static void renameColumnIdlistNames(
Parse *pParse,
RenameCtx *pCtx,
IdList *pIdList,
const char *zOld
){
if( pIdList ){
int i;
for(i=0; i<pIdList->nId; i++){
char *zName = pIdList->a[i].zName;
if( 0==sqlite3_stricmp(zName, zOld) ){
renameTokenFind(pParse, pCtx, (void*)zName);
}
}
}
}
/*
** Parse the SQL statement zSql using Parse object (*p). The Parse object
** is initialized by this function before it is used.
*/
static int renameParseSql(
Parse *p, /* Memory to use for Parse object */
const char *zDb, /* Name of schema SQL belongs to */
int bTable, /* 1 -> RENAME TABLE, 0 -> RENAME COLUMN */
sqlite3 *db, /* Database handle */
const char *zSql, /* SQL to parse */
int bTemp /* True if SQL is from temp schema */
){
int rc;
char *zErr = 0;
db->init.iDb = bTemp ? 1 : sqlite3FindDbName(db, zDb);
/* Parse the SQL statement passed as the first argument. If no error
** occurs and the parse does not result in a new table, index or
** trigger object, the database must be corrupt. */
memset(p, 0, sizeof(Parse));
p->eParseMode = (bTable ? PARSE_MODE_RENAME_TABLE : PARSE_MODE_RENAME_COLUMN);
p->db = db;
p->nQueryLoop = 1;
rc = sqlite3RunParser(p, zSql, &zErr);
assert( p->zErrMsg==0 );
assert( rc!=SQLITE_OK || zErr==0 );
p->zErrMsg = zErr;
if( db->mallocFailed ) rc = SQLITE_NOMEM;
if( rc==SQLITE_OK
&& p->pNewTable==0 && p->pNewIndex==0 && p->pNewTrigger==0
){
rc = SQLITE_CORRUPT_BKPT;
}
#ifdef SQLITE_DEBUG
/* Ensure that all mappings in the Parse.pRename list really do map to