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/*
** 2006 June 10
**
** 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 code used to help implement virtual tables.
*/
#ifndef SQLITE_OMIT_VIRTUALTABLE
#include "sqliteInt.h"
/*
** Before a virtual table xCreate() or xConnect() method is invoked, the
** sqlite3.pVtabCtx member variable is set to point to an instance of
** this struct allocated on the stack. It is used by the implementation of
** the sqlite3_declare_vtab() and sqlite3_vtab_config() APIs, both of which
** are invoked only from within xCreate and xConnect methods.
*/
struct VtabCtx {
VTable *pVTable; /* The virtual table being constructed */
Table *pTab; /* The Table object to which the virtual table belongs */
VtabCtx *pPrior; /* Parent context (if any) */
int bDeclared; /* True after sqlite3_declare_vtab() is called */
};
/*
** Construct and install a Module object for a virtual table. When this
** routine is called, it is guaranteed that all appropriate locks are held
** and the module is not already part of the connection.
**
** If there already exists a module with zName, replace it with the new one.
** If pModule==0, then delete the module zName if it exists.
*/
Module *sqlite3VtabCreateModule(
sqlite3 *db, /* Database in which module is registered */
const char *zName, /* Name assigned to this module */
const sqlite3_module *pModule, /* The definition of the module */
void *pAux, /* Context pointer for xCreate/xConnect */
void (*xDestroy)(void *) /* Module destructor function */
){
Module *pMod;
Module *pDel;
char *zCopy;
if( pModule==0 ){
zCopy = (char*)zName;
pMod = 0;
}else{
int nName = sqlite3Strlen30(zName);
pMod = (Module *)sqlite3Malloc(sizeof(Module) + nName + 1);
if( pMod==0 ){
sqlite3OomFault(db);
return 0;
}
zCopy = (char *)(&pMod[1]);
memcpy(zCopy, zName, nName+1);
pMod->zName = zCopy;
pMod->pModule = pModule;
pMod->pAux = pAux;
pMod->xDestroy = xDestroy;
pMod->pEpoTab = 0;
pMod->nRefModule = 1;
}
pDel = (Module *)sqlite3HashInsert(&db->aModule,zCopy,(void*)pMod);
if( pDel ){
if( pDel==pMod ){
sqlite3OomFault(db);
sqlite3DbFree(db, pDel);
pMod = 0;
}else{
sqlite3VtabEponymousTableClear(db, pDel);
sqlite3VtabModuleUnref(db, pDel);
}
}
return pMod;
}
/*
** The actual function that does the work of creating a new module.
** This function implements the sqlite3_create_module() and
** sqlite3_create_module_v2() interfaces.
*/
static int createModule(
sqlite3 *db, /* Database in which module is registered */
const char *zName, /* Name assigned to this module */
const sqlite3_module *pModule, /* The definition of the module */
void *pAux, /* Context pointer for xCreate/xConnect */
void (*xDestroy)(void *) /* Module destructor function */
){
int rc = SQLITE_OK;
sqlite3_mutex_enter(db->mutex);
(void)sqlite3VtabCreateModule(db, zName, pModule, pAux, xDestroy);
rc = sqlite3ApiExit(db, rc);
if( rc!=SQLITE_OK && xDestroy ) xDestroy(pAux);
sqlite3_mutex_leave(db->mutex);
return rc;
}
/*
** External API function used to create a new virtual-table module.
*/
int sqlite3_create_module(
sqlite3 *db, /* Database in which module is registered */
const char *zName, /* Name assigned to this module */
const sqlite3_module *pModule, /* The definition of the module */
void *pAux /* Context pointer for xCreate/xConnect */
){
#ifdef SQLITE_ENABLE_API_ARMOR
if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
#endif
return createModule(db, zName, pModule, pAux, 0);
}
/*
** External API function used to create a new virtual-table module.
*/
int sqlite3_create_module_v2(
sqlite3 *db, /* Database in which module is registered */
const char *zName, /* Name assigned to this module */
const sqlite3_module *pModule, /* The definition of the module */
void *pAux, /* Context pointer for xCreate/xConnect */
void (*xDestroy)(void *) /* Module destructor function */
){
#ifdef SQLITE_ENABLE_API_ARMOR
if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
#endif
return createModule(db, zName, pModule, pAux, xDestroy);
}
/*
** External API to drop all virtual-table modules, except those named
** on the azNames list.
*/
int sqlite3_drop_modules(sqlite3 *db, const char** azNames){
HashElem *pThis, *pNext;
#ifdef SQLITE_ENABLE_API_ARMOR
if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
#endif
for(pThis=sqliteHashFirst(&db->aModule); pThis; pThis=pNext){
Module *pMod = (Module*)sqliteHashData(pThis);
pNext = sqliteHashNext(pThis);
if( azNames ){
int ii;
for(ii=0; azNames[ii]!=0 && strcmp(azNames[ii],pMod->zName)!=0; ii++){}
if( azNames[ii]!=0 ) continue;
}
createModule(db, pMod->zName, 0, 0, 0);
}
return SQLITE_OK;
}
/*
** Decrement the reference count on a Module object. Destroy the
** module when the reference count reaches zero.
*/
void sqlite3VtabModuleUnref(sqlite3 *db, Module *pMod){
assert( pMod->nRefModule>0 );
pMod->nRefModule--;
if( pMod->nRefModule==0 ){
if( pMod->xDestroy ){
pMod->xDestroy(pMod->pAux);
}
assert( pMod->pEpoTab==0 );
sqlite3DbFree(db, pMod);
}
}
/*
** Lock the virtual table so that it cannot be disconnected.
** Locks nest. Every lock should have a corresponding unlock.
** If an unlock is omitted, resources leaks will occur.
**
** If a disconnect is attempted while a virtual table is locked,
** the disconnect is deferred until all locks have been removed.
*/
void sqlite3VtabLock(VTable *pVTab){
pVTab->nRef++;
}
/*
** pTab is a pointer to a Table structure representing a virtual-table.
** Return a pointer to the VTable object used by connection db to access
** this virtual-table, if one has been created, or NULL otherwise.
*/
VTable *sqlite3GetVTable(sqlite3 *db, Table *pTab){
VTable *pVtab;
assert( IsVirtual(pTab) );
for(pVtab=pTab->pVTable; pVtab && pVtab->db!=db; pVtab=pVtab->pNext);
return pVtab;
}
/*
** Decrement the ref-count on a virtual table object. When the ref-count
** reaches zero, call the xDisconnect() method to delete the object.
*/
void sqlite3VtabUnlock(VTable *pVTab){
sqlite3 *db = pVTab->db;
assert( db );
assert( pVTab->nRef>0 );
assert( db->magic==SQLITE_MAGIC_OPEN || db->magic==SQLITE_MAGIC_ZOMBIE );
pVTab->nRef--;
if( pVTab->nRef==0 ){
sqlite3_vtab *p = pVTab->pVtab;
sqlite3VtabModuleUnref(pVTab->db, pVTab->pMod);
if( p ){
p->pModule->xDisconnect(p);
}
sqlite3DbFree(db, pVTab);
}
}
/*
** Table p is a virtual table. This function moves all elements in the
** p->pVTable list to the sqlite3.pDisconnect lists of their associated
** database connections to be disconnected at the next opportunity.
** Except, if argument db is not NULL, then the entry associated with
** connection db is left in the p->pVTable list.
*/
static VTable *vtabDisconnectAll(sqlite3 *db, Table *p){
VTable *pRet = 0;
VTable *pVTable = p->pVTable;
p->pVTable = 0;
/* Assert that the mutex (if any) associated with the BtShared database
** that contains table p is held by the caller. See header comments
** above function sqlite3VtabUnlockList() for an explanation of why
** this makes it safe to access the sqlite3.pDisconnect list of any
** database connection that may have an entry in the p->pVTable list.
*/
assert( db==0 || sqlite3SchemaMutexHeld(db, 0, p->pSchema) );
while( pVTable ){
sqlite3 *db2 = pVTable->db;
VTable *pNext = pVTable->pNext;
assert( db2 );
if( db2==db ){
pRet = pVTable;
p->pVTable = pRet;
pRet->pNext = 0;
}else{
pVTable->pNext = db2->pDisconnect;
db2->pDisconnect = pVTable;
}
pVTable = pNext;
}
assert( !db || pRet );
return pRet;
}
/*
** Table *p is a virtual table. This function removes the VTable object
** for table *p associated with database connection db from the linked
** list in p->pVTab. It also decrements the VTable ref count. This is
** used when closing database connection db to free all of its VTable
** objects without disturbing the rest of the Schema object (which may
** be being used by other shared-cache connections).
*/
void sqlite3VtabDisconnect(sqlite3 *db, Table *p){
VTable **ppVTab;
assert( IsVirtual(p) );
assert( sqlite3BtreeHoldsAllMutexes(db) );
assert( sqlite3_mutex_held(db->mutex) );
for(ppVTab=&p->pVTable; *ppVTab; ppVTab=&(*ppVTab)->pNext){
if( (*ppVTab)->db==db ){
VTable *pVTab = *ppVTab;
*ppVTab = pVTab->pNext;
sqlite3VtabUnlock(pVTab);
break;
}
}
}
/*
** Disconnect all the virtual table objects in the sqlite3.pDisconnect list.
**
** This function may only be called when the mutexes associated with all
** shared b-tree databases opened using connection db are held by the
** caller. This is done to protect the sqlite3.pDisconnect list. The
** sqlite3.pDisconnect list is accessed only as follows:
**
** 1) By this function. In this case, all BtShared mutexes and the mutex
** associated with the database handle itself must be held.
**
** 2) By function vtabDisconnectAll(), when it adds a VTable entry to
** the sqlite3.pDisconnect list. In this case either the BtShared mutex
** associated with the database the virtual table is stored in is held
** or, if the virtual table is stored in a non-sharable database, then
** the database handle mutex is held.
**
** As a result, a sqlite3.pDisconnect cannot be accessed simultaneously
** by multiple threads. It is thread-safe.
*/
void sqlite3VtabUnlockList(sqlite3 *db){
VTable *p = db->pDisconnect;
db->pDisconnect = 0;
assert( sqlite3BtreeHoldsAllMutexes(db) );
assert( sqlite3_mutex_held(db->mutex) );
if( p ){
sqlite3ExpirePreparedStatements(db, 0);
do {
VTable *pNext = p->pNext;
sqlite3VtabUnlock(p);
p = pNext;
}while( p );
}
}
/*
** Clear any and all virtual-table information from the Table record.
** This routine is called, for example, just before deleting the Table
** record.
**
** Since it is a virtual-table, the Table structure contains a pointer
** to the head of a linked list of VTable structures. Each VTable
** structure is associated with a single sqlite3* user of the schema.
** The reference count of the VTable structure associated with database
** connection db is decremented immediately (which may lead to the
** structure being xDisconnected and free). Any other VTable structures
** in the list are moved to the sqlite3.pDisconnect list of the associated
** database connection.
*/
void sqlite3VtabClear(sqlite3 *db, Table *p){
if( !db || db->pnBytesFreed==0 ) vtabDisconnectAll(0, p);
if( p->azModuleArg ){
int i;
for(i=0; i<p->nModuleArg; i++){
if( i!=1 ) sqlite3DbFree(db, p->azModuleArg[i]);
}
sqlite3DbFree(db, p->azModuleArg);
}
}
/*
** Add a new module argument to pTable->azModuleArg[].
** The string is not copied - the pointer is stored. The
** string will be freed automatically when the table is
** deleted.
*/
static void addModuleArgument(Parse *pParse, Table *pTable, char *zArg){
sqlite3_int64 nBytes = sizeof(char *)*(2+pTable->nModuleArg);
char **azModuleArg;
sqlite3 *db = pParse->db;
if( pTable->nModuleArg+3>=db->aLimit[SQLITE_LIMIT_COLUMN] ){
sqlite3ErrorMsg(pParse, "too many columns on %s", pTable->zName);
}
azModuleArg = sqlite3DbRealloc(db, pTable->azModuleArg, nBytes);
if( azModuleArg==0 ){
sqlite3DbFree(db, zArg);
}else{
int i = pTable->nModuleArg++;
azModuleArg[i] = zArg;
azModuleArg[i+1] = 0;
pTable->azModuleArg = azModuleArg;
}
}
/*
** The parser calls this routine when it first sees a CREATE VIRTUAL TABLE
** statement. The module name has been parsed, but the optional list
** of parameters that follow the module name are still pending.
*/
void sqlite3VtabBeginParse(
Parse *pParse, /* Parsing context */
Token *pName1, /* Name of new table, or database name */
Token *pName2, /* Name of new table or NULL */
Token *pModuleName, /* Name of the module for the virtual table */
int ifNotExists /* No error if the table already exists */
){
Table *pTable; /* The new virtual table */
sqlite3 *db; /* Database connection */
sqlite3StartTable(pParse, pName1, pName2, 0, 0, 1, ifNotExists);
pTable = pParse->pNewTable;
if( pTable==0 ) return;
assert( 0==pTable->pIndex );
db = pParse->db;
assert( pTable->nModuleArg==0 );
addModuleArgument(pParse, pTable, sqlite3NameFromToken(db, pModuleName));
addModuleArgument(pParse, pTable, 0);
addModuleArgument(pParse, pTable, sqlite3DbStrDup(db, pTable->zName));
assert( (pParse->sNameToken.z==pName2->z && pName2->z!=0)
|| (pParse->sNameToken.z==pName1->z && pName2->z==0)
);
pParse->sNameToken.n = (int)(
&pModuleName->z[pModuleName->n] - pParse->sNameToken.z
);
#ifndef SQLITE_OMIT_AUTHORIZATION
/* Creating a virtual table invokes the authorization callback twice.
** The first invocation, to obtain permission to INSERT a row into the
** sqlite_master table, has already been made by sqlite3StartTable().
** The second call, to obtain permission to create the table, is made now.
*/
if( pTable->azModuleArg ){
int iDb = sqlite3SchemaToIndex(db, pTable->pSchema);
assert( iDb>=0 ); /* The database the table is being created in */
sqlite3AuthCheck(pParse, SQLITE_CREATE_VTABLE, pTable->zName,
pTable->azModuleArg[0], pParse->db->aDb[iDb].zDbSName);
}
#endif
}
/*
** This routine takes the module argument that has been accumulating
** in pParse->zArg[] and appends it to the list of arguments on the
** virtual table currently under construction in pParse->pTable.
*/
static void addArgumentToVtab(Parse *pParse){
if( pParse->sArg.z && pParse->pNewTable ){
const char *z = (const char*)pParse->sArg.z;
int n = pParse->sArg.n;
sqlite3 *db = pParse->db;
addModuleArgument(pParse, pParse->pNewTable, sqlite3DbStrNDup(db, z, n));
}
}
/*
** The parser calls this routine after the CREATE VIRTUAL TABLE statement
** has been completely parsed.
*/
void sqlite3VtabFinishParse(Parse *pParse, Token *pEnd){
Table *pTab = pParse->pNewTable; /* The table being constructed */
sqlite3 *db = pParse->db; /* The database connection */
if( pTab==0 ) return;
addArgumentToVtab(pParse);
pParse->sArg.z = 0;
if( pTab->nModuleArg<1 ) return;
/* If the CREATE VIRTUAL TABLE statement is being entered for the
** first time (in other words if the virtual table is actually being
** created now instead of just being read out of sqlite_master) then
** do additional initialization work and store the statement text
** in the sqlite_master table.
*/
if( !db->init.busy ){
char *zStmt;
char *zWhere;
int iDb;
int iReg;
Vdbe *v;
/* Compute the complete text of the CREATE VIRTUAL TABLE statement */
if( pEnd ){
pParse->sNameToken.n = (int)(pEnd->z - pParse->sNameToken.z) + pEnd->n;
}
zStmt = sqlite3MPrintf(db, "CREATE VIRTUAL TABLE %T", &pParse->sNameToken);
/* A slot for the record has already been allocated in the
** SQLITE_MASTER table. We just need to update that slot with all
** the information we've collected.
**
** The VM register number pParse->regRowid holds the rowid of an
** entry in the sqlite_master table tht was created for this vtab
** by sqlite3StartTable().
*/
iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
sqlite3NestedParse(pParse,
"UPDATE %Q.%s "
"SET type='table', name=%Q, tbl_name=%Q, rootpage=0, sql=%Q "
"WHERE rowid=#%d",
db->aDb[iDb].zDbSName, MASTER_NAME,
pTab->zName,
pTab->zName,
zStmt,
pParse->regRowid
);
sqlite3DbFree(db, zStmt);
v = sqlite3GetVdbe(pParse);
sqlite3ChangeCookie(pParse, iDb);
sqlite3VdbeAddOp0(v, OP_Expire);
zWhere = sqlite3MPrintf(db, "name='%q' AND type='table'", pTab->zName);
sqlite3VdbeAddParseSchemaOp(v, iDb, zWhere);
iReg = ++pParse->nMem;
sqlite3VdbeLoadString(v, iReg, pTab->zName);
sqlite3VdbeAddOp2(v, OP_VCreate, iDb, iReg);
}
/* If we are rereading the sqlite_master table create the in-memory
** record of the table. The xConnect() method is not called until
** the first time the virtual table is used in an SQL statement. This
** allows a schema that contains virtual tables to be loaded before
** the required virtual table implementations are registered. */
else {
Table *pOld;
Schema *pSchema = pTab->pSchema;
const char *zName = pTab->zName;
assert( sqlite3SchemaMutexHeld(db, 0, pSchema) );
pOld = sqlite3HashInsert(&pSchema->tblHash, zName, pTab);
if( pOld ){
sqlite3OomFault(db);
assert( pTab==pOld ); /* Malloc must have failed inside HashInsert() */
return;
}
pParse->pNewTable = 0;
}
}
/*
** The parser calls this routine when it sees the first token
** of an argument to the module name in a CREATE VIRTUAL TABLE statement.
*/
void sqlite3VtabArgInit(Parse *pParse){
addArgumentToVtab(pParse);
pParse->sArg.z = 0;
pParse->sArg.n = 0;
}
/*
** The parser calls this routine for each token after the first token
** in an argument to the module name in a CREATE VIRTUAL TABLE statement.
*/
void sqlite3VtabArgExtend(Parse *pParse, Token *p){
Token *pArg = &pParse->sArg;
if( pArg->z==0 ){
pArg->z = p->z;
pArg->n = p->n;
}else{
assert(pArg->z <= p->z);
pArg->n = (int)(&p->z[p->n] - pArg->z);
}
}
/*
** Invoke a virtual table constructor (either xCreate or xConnect). The
** pointer to the function to invoke is passed as the fourth parameter
** to this procedure.
*/
static int vtabCallConstructor(
sqlite3 *db,
Table *pTab,
Module *pMod,
int (*xConstruct)(sqlite3*,void*,int,const char*const*,sqlite3_vtab**,char**),
char **pzErr
){
VtabCtx sCtx;
VTable *pVTable;
int rc;
const char *const*azArg = (const char *const*)pTab->azModuleArg;
int nArg = pTab->nModuleArg;
char *zErr = 0;
char *zModuleName;
int iDb;
VtabCtx *pCtx;
/* Check that the virtual-table is not already being initialized */
for(pCtx=db->pVtabCtx; pCtx; pCtx=pCtx->pPrior){
if( pCtx->pTab==pTab ){
*pzErr = sqlite3MPrintf(db,
"vtable constructor called recursively: %s", pTab->zName
);
return SQLITE_LOCKED;
}
}
zModuleName = sqlite3DbStrDup(db, pTab->zName);
if( !zModuleName ){
return SQLITE_NOMEM_BKPT;
}
pVTable = sqlite3MallocZero(sizeof(VTable));
if( !pVTable ){
sqlite3OomFault(db);
sqlite3DbFree(db, zModuleName);
return SQLITE_NOMEM_BKPT;
}
pVTable->db = db;
pVTable->pMod = pMod;
iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
pTab->azModuleArg[1] = db->aDb[iDb].zDbSName;
/* Invoke the virtual table constructor */
assert( &db->pVtabCtx );
assert( xConstruct );
sCtx.pTab = pTab;
sCtx.pVTable = pVTable;
sCtx.pPrior = db->pVtabCtx;
sCtx.bDeclared = 0;
db->pVtabCtx = &sCtx;
rc = xConstruct(db, pMod->pAux, nArg, azArg, &pVTable->pVtab, &zErr);
db->pVtabCtx = sCtx.pPrior;
if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
assert( sCtx.pTab==pTab );
if( SQLITE_OK!=rc ){
if( zErr==0 ){
*pzErr = sqlite3MPrintf(db, "vtable constructor failed: %s", zModuleName);
}else {
*pzErr = sqlite3MPrintf(db, "%s", zErr);
sqlite3_free(zErr);
}
sqlite3DbFree(db, pVTable);
}else if( ALWAYS(pVTable->pVtab) ){
/* Justification of ALWAYS(): A correct vtab constructor must allocate
** the sqlite3_vtab object if successful. */
memset(pVTable->pVtab, 0, sizeof(pVTable->pVtab[0]));
pVTable->pVtab->pModule = pMod->pModule;
pMod->nRefModule++;
pVTable->nRef = 1;
if( sCtx.bDeclared==0 ){
const char *zFormat = "vtable constructor did not declare schema: %s";
*pzErr = sqlite3MPrintf(db, zFormat, pTab->zName);
sqlite3VtabUnlock(pVTable);
rc = SQLITE_ERROR;
}else{
int iCol;
u8 oooHidden = 0;
/* If everything went according to plan, link the new VTable structure
** into the linked list headed by pTab->pVTable. Then loop through the
** columns of the table to see if any of them contain the token "hidden".
** If so, set the Column COLFLAG_HIDDEN flag and remove the token from
** the type string. */
pVTable->pNext = pTab->pVTable;
pTab->pVTable = pVTable;
for(iCol=0; iCol<pTab->nCol; iCol++){
char *zType = sqlite3ColumnType(&pTab->aCol[iCol], "");
int nType;
int i = 0;
nType = sqlite3Strlen30(zType);
for(i=0; i<nType; i++){
if( 0==sqlite3StrNICmp("hidden", &zType[i], 6)
&& (i==0 || zType[i-1]==' ')
&& (zType[i+6]=='\0' || zType[i+6]==' ')
){
break;
}
}
if( i<nType ){
int j;
int nDel = 6 + (zType[i+6] ? 1 : 0);
for(j=i; (j+nDel)<=nType; j++){
zType[j] = zType[j+nDel];
}
if( zType[i]=='\0' && i>0 ){
assert(zType[i-1]==' ');
zType[i-1] = '\0';
}
pTab->aCol[iCol].colFlags |= COLFLAG_HIDDEN;
oooHidden = TF_OOOHidden;
}else{
pTab->tabFlags |= oooHidden;
}
}
}
}
sqlite3DbFree(db, zModuleName);
return rc;
}
/*
** This function is invoked by the parser to call the xConnect() method
** of the virtual table pTab. If an error occurs, an error code is returned
** and an error left in pParse.
**
** This call is a no-op if table pTab is not a virtual table.
*/
int sqlite3VtabCallConnect(Parse *pParse, Table *pTab){
sqlite3 *db = pParse->db;
const char *zMod;
Module *pMod;
int rc;
assert( pTab );
if( !IsVirtual(pTab) || sqlite3GetVTable(db, pTab) ){
return SQLITE_OK;
}
/* Locate the required virtual table module */
zMod = pTab->azModuleArg[0];
pMod = (Module*)sqlite3HashFind(&db->aModule, zMod);
if( !pMod ){
const char *zModule = pTab->azModuleArg[0];
sqlite3ErrorMsg(pParse, "no such module: %s", zModule);
rc = SQLITE_ERROR;
}else{
char *zErr = 0;
rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xConnect, &zErr);
if( rc!=SQLITE_OK ){
sqlite3ErrorMsg(pParse, "%s", zErr);
pParse->rc = rc;
}
sqlite3DbFree(db, zErr);
}
return rc;
}
/*
** Grow the db->aVTrans[] array so that there is room for at least one
** more v-table. Return SQLITE_NOMEM if a malloc fails, or SQLITE_OK otherwise.
*/
static int growVTrans(sqlite3 *db){
const int ARRAY_INCR = 5;
/* Grow the sqlite3.aVTrans array if required */
if( (db->nVTrans%ARRAY_INCR)==0 ){
VTable **aVTrans;
sqlite3_int64 nBytes = sizeof(sqlite3_vtab*)*
((sqlite3_int64)db->nVTrans + ARRAY_INCR);
aVTrans = sqlite3DbRealloc(db, (void *)db->aVTrans, nBytes);
if( !aVTrans ){
return SQLITE_NOMEM_BKPT;
}
memset(&aVTrans[db->nVTrans], 0, sizeof(sqlite3_vtab *)*ARRAY_INCR);
db->aVTrans = aVTrans;
}
return SQLITE_OK;
}
/*
** Add the virtual table pVTab to the array sqlite3.aVTrans[]. Space should
** have already been reserved using growVTrans().
*/
static void addToVTrans(sqlite3 *db, VTable *pVTab){
/* Add pVtab to the end of sqlite3.aVTrans */
db->aVTrans[db->nVTrans++] = pVTab;
sqlite3VtabLock(pVTab);
}
/*
** This function is invoked by the vdbe to call the xCreate method
** of the virtual table named zTab in database iDb.
**
** If an error occurs, *pzErr is set to point to an English language
** description of the error and an SQLITE_XXX error code is returned.
** In this case the caller must call sqlite3DbFree(db, ) on *pzErr.
*/
int sqlite3VtabCallCreate(sqlite3 *db, int iDb, const char *zTab, char **pzErr){
int rc = SQLITE_OK;
Table *pTab;
Module *pMod;
const char *zMod;
pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zDbSName);
assert( pTab && IsVirtual(pTab) && !pTab->pVTable );
/* Locate the required virtual table module */
zMod = pTab->azModuleArg[0];
pMod = (Module*)sqlite3HashFind(&db->aModule, zMod);
/* If the module has been registered and includes a Create method,
** invoke it now. If the module has not been registered, return an
** error. Otherwise, do nothing.
*/
if( pMod==0 || pMod->pModule->xCreate==0 || pMod->pModule->xDestroy==0 ){
*pzErr = sqlite3MPrintf(db, "no such module: %s", zMod);
rc = SQLITE_ERROR;
}else{
rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xCreate, pzErr);
}
/* Justification of ALWAYS(): The xConstructor method is required to
** create a valid sqlite3_vtab if it returns SQLITE_OK. */
if( rc==SQLITE_OK && ALWAYS(sqlite3GetVTable(db, pTab)) ){
rc = growVTrans(db);
if( rc==SQLITE_OK ){
addToVTrans(db, sqlite3GetVTable(db, pTab));
}
}
return rc;
}
/*
** This function is used to set the schema of a virtual table. It is only
** valid to call this function from within the xCreate() or xConnect() of a
** virtual table module.
*/
int sqlite3_declare_vtab(sqlite3 *db, const char *zCreateTable){
VtabCtx *pCtx;
int rc = SQLITE_OK;
Table *pTab;
char *zErr = 0;
Parse sParse;
#ifdef SQLITE_ENABLE_API_ARMOR
if( !sqlite3SafetyCheckOk(db) || zCreateTable==0 ){
return SQLITE_MISUSE_BKPT;
}
#endif
sqlite3_mutex_enter(db->mutex);
pCtx = db->pVtabCtx;
if( !pCtx || pCtx->bDeclared ){
sqlite3Error(db, SQLITE_MISUSE);
sqlite3_mutex_leave(db->mutex);
return SQLITE_MISUSE_BKPT;
}
pTab = pCtx->pTab;
assert( IsVirtual(pTab) );
memset(&sParse, 0, sizeof(sParse));
sParse.eParseMode = PARSE_MODE_DECLARE_VTAB;
sParse.db = db;
sParse.nQueryLoop = 1;
if( SQLITE_OK==sqlite3RunParser(&sParse, zCreateTable, &zErr)
&& sParse.pNewTable
&& !db->mallocFailed
&& !sParse.pNewTable->pSelect
&& !IsVirtual(sParse.pNewTable)
){
if( !pTab->aCol ){
Table *pNew = sParse.pNewTable;
Index *pIdx;
pTab->aCol = pNew->aCol;
pTab->nCol = pNew->nCol;
pTab->tabFlags |= pNew->tabFlags & (TF_WithoutRowid|TF_NoVisibleRowid);
pNew->nCol = 0;
pNew->aCol = 0;
assert( pTab->pIndex==0 );
assert( HasRowid(pNew) || sqlite3PrimaryKeyIndex(pNew)!=0 );
if( !HasRowid(pNew)
&& pCtx->pVTable->pMod->pModule->xUpdate!=0
&& sqlite3PrimaryKeyIndex(pNew)->nKeyCol!=1
){
/* WITHOUT ROWID virtual tables must either be read-only (xUpdate==0)
** or else must have a single-column PRIMARY KEY */
rc = SQLITE_ERROR;
}
pIdx = pNew->pIndex;
if( pIdx ){
assert( pIdx->pNext==0 );
pTab->pIndex = pIdx;
pNew->pIndex = 0;
pIdx->pTable = pTab;
}
}
pCtx->bDeclared = 1;
}else{
sqlite3ErrorWithMsg(db, SQLITE_ERROR, (zErr ? "%s" : 0), zErr);
sqlite3DbFree(db, zErr);
rc = SQLITE_ERROR;
}
sParse.eParseMode = PARSE_MODE_NORMAL;
if( sParse.pVdbe ){
sqlite3VdbeFinalize(sParse.pVdbe);
}
sqlite3DeleteTable(db, sParse.pNewTable);
sqlite3ParserReset(&sParse);
assert( (rc&0xff)==rc );
rc = sqlite3ApiExit(db, rc);
sqlite3_mutex_leave(db->mutex);
return rc;
}
/*
** This function is invoked by the vdbe to call the xDestroy method
** of the virtual table named zTab in database iDb. This occurs
** when a DROP TABLE is mentioned.
**
** This call is a no-op if zTab is not a virtual table.
*/
int sqlite3VtabCallDestroy(sqlite3 *db, int iDb, const char *zTab){
int rc = SQLITE_OK;
Table *pTab;
pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zDbSName);
if( pTab!=0 && ALWAYS(pTab->pVTable!=0) ){
VTable *p;
int (*xDestroy)(sqlite3_vtab *);
for(p=pTab->pVTable; p; p=p->pNext){
assert( p->pVtab );
if( p->pVtab->nRef>0 ){
return SQLITE_LOCKED;
}
}
p = vtabDisconnectAll(db, pTab);
xDestroy = p->pMod->pModule->xDestroy;
assert( xDestroy!=0 ); /* Checked before the virtual table is created */
pTab->nTabRef++;
rc = xDestroy(p->pVtab);
/* Remove the sqlite3_vtab* from the aVTrans[] array, if applicable */
if( rc==SQLITE_OK ){
assert( pTab->pVTable==p && p->pNext==0 );
p->pVtab = 0;
pTab->pVTable = 0;
sqlite3VtabUnlock(p);
}
sqlite3DeleteTable(db, pTab);
}
return rc;
}
/*
** This function invokes either the xRollback or xCommit method
** of each of the virtual tables in the sqlite3.aVTrans array. The method
** called is identified by the second argument, "offset", which is
** the offset of the method to call in the sqlite3_module structure.
**
** The array is cleared after invoking the callbacks.
*/
static void callFinaliser(sqlite3 *db, int offset){
int i;
if( db->aVTrans ){
VTable **aVTrans = db->aVTrans;
db->aVTrans = 0;
for(i=0; i<db->nVTrans; i++){
VTable *pVTab = aVTrans[i];
sqlite3_vtab *p = pVTab->pVtab;
if( p ){
int (*x)(sqlite3_vtab *);
x = *(int (**)(sqlite3_vtab *))((char *)p->pModule + offset);
if( x ) x(p);
}
pVTab->iSavepoint = 0;
sqlite3VtabUnlock(pVTab);
}
sqlite3DbFree(db, aVTrans);
db->nVTrans = 0;
}
}
/*
** Invoke the xSync method of all virtual tables in the sqlite3.aVTrans
** array. Return the error code for the first error that occurs, or
** SQLITE_OK if all xSync operations are successful.
**
** If an error message is available, leave it in p->zErrMsg.
*/
int sqlite3VtabSync(sqlite3 *db, Vdbe *p){
int i;
int rc = SQLITE_OK;
VTable **aVTrans = db->aVTrans;
db->aVTrans = 0;
for(i=0; rc==SQLITE_OK && i<db->nVTrans; i++){
int (*x)(sqlite3_vtab *);
sqlite3_vtab *pVtab = aVTrans[i]->pVtab;
if( pVtab && (x = pVtab->pModule->xSync)!=0 ){
rc = x(pVtab);
sqlite3VtabImportErrmsg(p, pVtab);
}
}
db->aVTrans = aVTrans;
return rc;
}
/*
** Invoke the xRollback method of all virtual tables in the
** sqlite3.aVTrans array. Then clear the array itself.
*/
int sqlite3VtabRollback(sqlite3 *db){
callFinaliser(db, offsetof(sqlite3_module,xRollback));
return SQLITE_OK;
}
/*
** Invoke the xCommit method of all virtual tables in the
** sqlite3.aVTrans array. Then clear the array itself.
*/
int sqlite3VtabCommit(sqlite3 *db){
callFinaliser(db, offsetof(sqlite3_module,xCommit));
return SQLITE_OK;
}
/*
** If the virtual table pVtab supports the transaction interface
** (xBegin/xRollback/xCommit and optionally xSync) and a transaction is
** not currently open, invoke the xBegin method now.
**
** If the xBegin call is successful, place the sqlite3_vtab pointer
** in the sqlite3.aVTrans array.
*/
int sqlite3VtabBegin(sqlite3 *db, VTable *pVTab){
int rc = SQLITE_OK;
const sqlite3_module *pModule;
/* Special case: If db->aVTrans is NULL and db->nVTrans is greater
** than zero, then this function is being called from within a
** virtual module xSync() callback. It is illegal to write to
** virtual module tables in this case, so return SQLITE_LOCKED.
*/
if( sqlite3VtabInSync(db) ){
return SQLITE_LOCKED;
}
if( !pVTab ){
return SQLITE_OK;
}
pModule = pVTab->pVtab->pModule;
if( pModule->xBegin ){
int i;
/* If pVtab is already in the aVTrans array, return early */
for(i=0; i<db->nVTrans; i++){
if( db->aVTrans[i]==pVTab ){
return SQLITE_OK;
}
}
/* Invoke the xBegin method. If successful, add the vtab to the
** sqlite3.aVTrans[] array. */
rc = growVTrans(db);
if( rc==SQLITE_OK ){
rc = pModule->xBegin(pVTab->pVtab);
if( rc==SQLITE_OK ){
int iSvpt = db->nStatement + db->nSavepoint;
addToVTrans(db, pVTab);
if( iSvpt && pModule->xSavepoint ){
pVTab->iSavepoint = iSvpt;
rc = pModule->xSavepoint(pVTab->pVtab, iSvpt-1);
}
}
}
}
return rc;
}
/*
** Invoke either the xSavepoint, xRollbackTo or xRelease method of all
** virtual tables that currently have an open transaction. Pass iSavepoint
** as the second argument to the virtual table method invoked.
**
** If op is SAVEPOINT_BEGIN, the xSavepoint method is invoked. If it is
** SAVEPOINT_ROLLBACK, the xRollbackTo method. Otherwise, if op is
** SAVEPOINT_RELEASE, then the xRelease method of each virtual table with
** an open transaction is invoked.
**
** If any virtual table method returns an error code other than SQLITE_OK,
** processing is abandoned and the error returned to the caller of this
** function immediately. If all calls to virtual table methods are successful,
** SQLITE_OK is returned.
*/
int sqlite3VtabSavepoint(sqlite3 *db, int op, int iSavepoint){
int rc = SQLITE_OK;
assert( op==SAVEPOINT_RELEASE||op==SAVEPOINT_ROLLBACK||op==SAVEPOINT_BEGIN );
assert( iSavepoint>=-1 );
if( db->aVTrans ){
int i;
for(i=0; rc==SQLITE_OK && i<db->nVTrans; i++){
VTable *pVTab = db->aVTrans[i];
const sqlite3_module *pMod = pVTab->pMod->pModule;
if( pVTab->pVtab && pMod->iVersion>=2 ){
int (*xMethod)(sqlite3_vtab *, int);
sqlite3VtabLock(pVTab);
switch( op ){
case SAVEPOINT_BEGIN:
xMethod = pMod->xSavepoint;
pVTab->iSavepoint = iSavepoint+1;
break;
case SAVEPOINT_ROLLBACK:
xMethod = pMod->xRollbackTo;
break;
default:
xMethod = pMod->xRelease;
break;
}
if( xMethod && pVTab->iSavepoint>iSavepoint ){
rc = xMethod(pVTab->pVtab, iSavepoint);
}
sqlite3VtabUnlock(pVTab);
}
}
}
return rc;
}
/*
** The first parameter (pDef) is a function implementation. The
** second parameter (pExpr) is the first argument to this function.
** If pExpr is a column in a virtual table, then let the virtual
** table implementation have an opportunity to overload the function.
**
** This routine is used to allow virtual table implementations to
** overload MATCH, LIKE, GLOB, and REGEXP operators.
**
** Return either the pDef argument (indicating no change) or a
** new FuncDef structure that is marked as ephemeral using the
** SQLITE_FUNC_EPHEM flag.
*/
FuncDef *sqlite3VtabOverloadFunction(
sqlite3 *db, /* Database connection for reporting malloc problems */
FuncDef *pDef, /* Function to possibly overload */
int nArg, /* Number of arguments to the function */
Expr *pExpr /* First argument to the function */
){
Table *pTab;
sqlite3_vtab *pVtab;
sqlite3_module *pMod;
void (*xSFunc)(sqlite3_context*,int,sqlite3_value**) = 0;
void *pArg = 0;
FuncDef *pNew;
int rc = 0;
/* Check to see the left operand is a column in a virtual table */
if( NEVER(pExpr==0) ) return pDef;
if( pExpr->op!=TK_COLUMN ) return pDef;
pTab = pExpr->y.pTab;
if( pTab==0 ) return pDef;
if( !IsVirtual(pTab) ) return pDef;
pVtab = sqlite3GetVTable(db, pTab)->pVtab;
assert( pVtab!=0 );
assert( pVtab->pModule!=0 );
pMod = (sqlite3_module *)pVtab->pModule;
if( pMod->xFindFunction==0 ) return pDef;
/* Call the xFindFunction method on the virtual table implementation
** to see if the implementation wants to overload this function.
**
** Though undocumented, we have historically always invoked xFindFunction
** with an all lower-case function name. Continue in this tradition to
** avoid any chance of an incompatibility.
*/
#ifdef SQLITE_DEBUG
{
int i;
for(i=0; pDef->zName[i]; i++){
unsigned char x = (unsigned char)pDef->zName[i];
assert( x==sqlite3UpperToLower[x] );
}
}
#endif
rc = pMod->xFindFunction(pVtab, nArg, pDef->zName, &xSFunc, &pArg);
if( rc==0 ){
return pDef;
}
/* Create a new ephemeral function definition for the overloaded
** function */
pNew = sqlite3DbMallocZero(db, sizeof(*pNew)
+ sqlite3Strlen30(pDef->zName) + 1);
if( pNew==0 ){
return pDef;
}
*pNew = *pDef;
pNew->zName = (const char*)&pNew[1];
memcpy((char*)&pNew[1], pDef->zName, sqlite3Strlen30(pDef->zName)+1);
pNew->xSFunc = xSFunc;
pNew->pUserData = pArg;
pNew->funcFlags |= SQLITE_FUNC_EPHEM;
return pNew;
}
/*
** Make sure virtual table pTab is contained in the pParse->apVirtualLock[]
** array so that an OP_VBegin will get generated for it. Add pTab to the
** array if it is missing. If pTab is already in the array, this routine
** is a no-op.
*/
void sqlite3VtabMakeWritable(Parse *pParse, Table *pTab){
Parse *pToplevel = sqlite3ParseToplevel(pParse);
int i, n;
Table **apVtabLock;
assert( IsVirtual(pTab) );
for(i=0; i<pToplevel->nVtabLock; i++){
if( pTab==pToplevel->apVtabLock[i] ) return;
}
n = (pToplevel->nVtabLock+1)*sizeof(pToplevel->apVtabLock[0]);
apVtabLock = sqlite3_realloc64(pToplevel->apVtabLock, n);
if( apVtabLock ){
pToplevel->apVtabLock = apVtabLock;
pToplevel->apVtabLock[pToplevel->nVtabLock++] = pTab;
}else{
sqlite3OomFault(pToplevel->db);
}
}
/*
** Check to see if virtual table module pMod can be have an eponymous
** virtual table instance. If it can, create one if one does not already
** exist. Return non-zero if the eponymous virtual table instance exists
** when this routine returns, and return zero if it does not exist.
**
** An eponymous virtual table instance is one that is named after its
** module, and more importantly, does not require a CREATE VIRTUAL TABLE
** statement in order to come into existance. Eponymous virtual table
** instances always exist. They cannot be DROP-ed.
**
** Any virtual table module for which xConnect and xCreate are the same
** method can have an eponymous virtual table instance.
*/
int sqlite3VtabEponymousTableInit(Parse *pParse, Module *pMod){
const sqlite3_module *pModule = pMod->pModule;
Table *pTab;
char *zErr = 0;
int rc;
sqlite3 *db = pParse->db;
if( pMod->pEpoTab ) return 1;
if( pModule->xCreate!=0 && pModule->xCreate!=pModule->xConnect ) return 0;
pTab = sqlite3DbMallocZero(db, sizeof(Table));
if( pTab==0 ) return 0;
pTab->zName = sqlite3DbStrDup(db, pMod->zName);
if( pTab->zName==0 ){
sqlite3DbFree(db, pTab);
return 0;
}
pMod->pEpoTab = pTab;
pTab->nTabRef = 1;
pTab->pSchema = db->aDb[0].pSchema;
assert( pTab->nModuleArg==0 );
pTab->iPKey = -1;
addModuleArgument(pParse, pTab, sqlite3DbStrDup(db, pTab->zName));
addModuleArgument(pParse, pTab, 0);
addModuleArgument(pParse, pTab, sqlite3DbStrDup(db, pTab->zName));
rc = vtabCallConstructor(db, pTab, pMod, pModule->xConnect, &zErr);
if( rc ){
sqlite3ErrorMsg(pParse, "%s", zErr);
sqlite3DbFree(db, zErr);
sqlite3VtabEponymousTableClear(db, pMod);
return 0;
}
return 1;
}
/*
** Erase the eponymous virtual table instance associated with
** virtual table module pMod, if it exists.
*/
void sqlite3VtabEponymousTableClear(sqlite3 *db, Module *pMod){
Table *pTab = pMod->pEpoTab;
if( pTab!=0 ){
/* Mark the table as Ephemeral prior to deleting it, so that the
** sqlite3DeleteTable() routine will know that it is not stored in
** the schema. */
pTab->tabFlags |= TF_Ephemeral;
sqlite3DeleteTable(db, pTab);
pMod->pEpoTab = 0;
}
}
/*
** Return the ON CONFLICT resolution mode in effect for the virtual
** table update operation currently in progress.
**
** The results of this routine are undefined unless it is called from
** within an xUpdate method.
*/
int sqlite3_vtab_on_conflict(sqlite3 *db){
static const unsigned char aMap[] = {
SQLITE_ROLLBACK, SQLITE_ABORT, SQLITE_FAIL, SQLITE_IGNORE, SQLITE_REPLACE
};
#ifdef SQLITE_ENABLE_API_ARMOR
if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
#endif
assert( OE_Rollback==1 && OE_Abort==2 && OE_Fail==3 );
assert( OE_Ignore==4 && OE_Replace==5 );
assert( db->vtabOnConflict>=1 && db->vtabOnConflict<=5 );
return (int)aMap[db->vtabOnConflict-1];
}
/*
** Call from within the xCreate() or xConnect() methods to provide
** the SQLite core with additional information about the behavior
** of the virtual table being implemented.
*/
int sqlite3_vtab_config(sqlite3 *db, int op, ...){
va_list ap;
int rc = SQLITE_OK;
#ifdef SQLITE_ENABLE_API_ARMOR
if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
#endif
sqlite3_mutex_enter(db->mutex);
va_start(ap, op);
switch( op ){
case SQLITE_VTAB_CONSTRAINT_SUPPORT: {
VtabCtx *p = db->pVtabCtx;
if( !p ){
rc = SQLITE_MISUSE_BKPT;
}else{
assert( p->pTab==0 || IsVirtual(p->pTab) );
p->pVTable->bConstraint = (u8)va_arg(ap, int);
}
break;
}
default:
rc = SQLITE_MISUSE_BKPT;
break;
}
va_end(ap);
if( rc!=SQLITE_OK ) sqlite3Error(db, rc);
sqlite3_mutex_leave(db->mutex);
return rc;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */