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Initial implementation of eponymous virtual table instances.

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FossilOrigin-Name: c1f43a7799a9298abea01b2f8531fc7cdadc4594
This commit is contained in:
drh
2015-08-19 02:32:25 +00:00
parent 0cbb513a67
commit 51be3873c0
6 changed files with 100 additions and 15 deletions
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62
src/vtab.c
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@@ -58,6 +58,7 @@ static int createModule(
pMod->pModule = pModule;
pMod->pAux = pAux;
pMod->xDestroy = xDestroy;
pMod->pEpoTab = 0;
pDel = (Module *)sqlite3HashInsert(&db->aModule,zCopy,(void*)pMod);
assert( pDel==0 || pDel==pMod );
if( pDel ){
@@ -275,6 +276,7 @@ void sqlite3VtabClear(sqlite3 *db, Table *p){
if( i!=1 ) sqlite3DbFree(db, p->azModuleArg[i]);
}
sqlite3DbFree(db, p->azModuleArg);
p->azModuleArg = 0;
}
}
@@ -1092,6 +1094,66 @@ void sqlite3VtabMakeWritable(Parse *pParse, Table *pTab){
}
}
/*
** Check to see if virtual tale 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 nName;
int rc;
sqlite3 *db = pParse->db;
if( pMod->pEpoTab ) return 1;
if( pModule->xCreate!=pModule->xConnect ) return 0;
nName = sqlite3Strlen30(pMod->zName) + 1;
pTab = sqlite3DbMallocZero(db, sizeof(Table) + nName);
if( pTab==0 ) return 0;
pMod->pEpoTab = pTab;
pTab->zName = (char*)&pTab[1];
memcpy(pTab->zName, pMod->zName, nName);
pTab->nRef = 1;
pTab->pSchema = db->aDb[0].pSchema;
pTab->tabFlags |= TF_Virtual;
pTab->nModuleArg = 0;
addModuleArgument(db, pTab, pTab->zName);
addModuleArgument(db, pTab, 0);
addModuleArgument(db, pTab, 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 = pMod->pEpoTab)!=0 ){
sqlite3DeleteColumnNames(db, pTab);
sqlite3DbFree(db, pTab->azModuleArg);
sqlite3DbFree(db, pTab);
pMod->pEpoTab = 0;
}
}
/*
** Return the ON CONFLICT resolution mode in effect for the virtual
** table update operation currently in progress.