functioncmds.c

来自「PostgreSQL7.4.6 for Linux」· C语言 代码 · 共 1,115 行 · 第 1/3 页

	/* update the catalog and its indexes */
	simple_heap_update(pg_proc_rel, &tup->t_self, tup);

	CatalogUpdateIndexes(pg_proc_rel, tup);

	heap_close(pg_proc_rel, RowExclusiveLock);
}


/*
 * SetFunctionArgType - change declared argument type of a function
 *
 * As above, but change an argument's type.
 */
void
SetFunctionArgType(Oid funcOid, int argIndex, Oid newArgType)
{
	Relation	pg_proc_rel;
	HeapTuple	tup;
	Form_pg_proc procForm;

	pg_proc_rel = heap_openr(ProcedureRelationName, RowExclusiveLock);

	tup = SearchSysCacheCopy(PROCOID,
							 ObjectIdGetDatum(funcOid),
							 0, 0, 0);
	if (!HeapTupleIsValid(tup)) /* should not happen */
		elog(ERROR, "cache lookup failed for function %u", funcOid);
	procForm = (Form_pg_proc) GETSTRUCT(tup);

	if (argIndex < 0 || argIndex >= procForm->pronargs ||
		procForm->proargtypes[argIndex] != OPAQUEOID)
		elog(ERROR, "function %u doesn't take OPAQUE", funcOid);

	/* okay to overwrite copied tuple */
	procForm->proargtypes[argIndex] = newArgType;

	/* update the catalog and its indexes */
	simple_heap_update(pg_proc_rel, &tup->t_self, tup);

	CatalogUpdateIndexes(pg_proc_rel, tup);

	heap_close(pg_proc_rel, RowExclusiveLock);
}



/*
 * CREATE CAST
 */
void
CreateCast(CreateCastStmt *stmt)
{
	Oid			sourcetypeid;
	Oid			targettypeid;
	Oid			funcid;
	char		castcontext;
	Relation	relation;
	HeapTuple	tuple;
	Datum		values[Natts_pg_cast];
	char		nulls[Natts_pg_cast];
	ObjectAddress myself,
				referenced;

	sourcetypeid = LookupTypeName(stmt->sourcetype);
	if (!OidIsValid(sourcetypeid))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("source data type %s does not exist",
						TypeNameToString(stmt->sourcetype))));

	targettypeid = LookupTypeName(stmt->targettype);
	if (!OidIsValid(targettypeid))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("target data type %s does not exist",
						TypeNameToString(stmt->targettype))));

	if (sourcetypeid == targettypeid)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
		  errmsg("source data type and target data type are the same")));

	/* No shells, no pseudo-types allowed */
	if (!get_typisdefined(sourcetypeid))
		ereport(ERROR,
				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
				 errmsg("source data type %s is only a shell",
						TypeNameToString(stmt->sourcetype))));

	if (!get_typisdefined(targettypeid))
		ereport(ERROR,
				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
				 errmsg("target data type %s is only a shell",
						TypeNameToString(stmt->targettype))));

	if (get_typtype(sourcetypeid) == 'p')
		ereport(ERROR,
				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
				 errmsg("source data type %s is a pseudo-type",
						TypeNameToString(stmt->sourcetype))));

	if (get_typtype(targettypeid) == 'p')
		ereport(ERROR,
				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
				 errmsg("target data type %s is a pseudo-type",
						TypeNameToString(stmt->targettype))));

	/* Permission check */
	if (!pg_type_ownercheck(sourcetypeid, GetUserId())
		&& !pg_type_ownercheck(targettypeid, GetUserId()))
		ereport(ERROR,
				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
				 errmsg("must be owner of type %s or type %s",
						TypeNameToString(stmt->sourcetype),
						TypeNameToString(stmt->targettype))));

	if (stmt->func != NULL)
	{
		Form_pg_proc procstruct;

		funcid = LookupFuncNameTypeNames(stmt->func->funcname,
										 stmt->func->funcargs,
										 false);

		tuple = SearchSysCache(PROCOID,
							   ObjectIdGetDatum(funcid),
							   0, 0, 0);
		if (!HeapTupleIsValid(tuple))
			elog(ERROR, "cache lookup failed for function %u", funcid);

		procstruct = (Form_pg_proc) GETSTRUCT(tuple);
		if (procstruct->pronargs != 1)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
					 errmsg("cast function must take one argument")));
		if (procstruct->proargtypes[0] != sourcetypeid)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
					 errmsg("argument of cast function must match source data type")));
		if (procstruct->prorettype != targettypeid)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
					 errmsg("return data type of cast function must match target data type")));

		/*
		 * Restricting the volatility of a cast function may or may not be
		 * a good idea in the abstract, but it definitely breaks many old
		 * user-defined types.	Disable this check --- tgl 2/1/03
		 */
#ifdef NOT_USED
		if (procstruct->provolatile == PROVOLATILE_VOLATILE)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
					 errmsg("cast function must not be volatile")));
#endif
		if (procstruct->proisagg)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
			 errmsg("cast function must not be an aggregate function")));
		if (procstruct->proretset)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
					 errmsg("cast function must not return a set")));

		ReleaseSysCache(tuple);
	}
	else
	{
		int16		typ1len;
		int16		typ2len;
		bool		typ1byval;
		bool		typ2byval;
		char		typ1align;
		char		typ2align;

		/* indicates binary coercibility */
		funcid = InvalidOid;

		/*
		 * Must be superuser to create binary-compatible casts, since
		 * erroneous casts can easily crash the backend.
		 */
		if (!superuser())
			ereport(ERROR,
					(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
					 errmsg("must be superuser to create a cast WITHOUT FUNCTION")));

		/*
		 * Also, insist that the types match as to size, alignment, and
		 * pass-by-value attributes; this provides at least a crude check
		 * that they have similar representations.	A pair of types that
		 * fail this test should certainly not be equated.
		 */
		get_typlenbyvalalign(sourcetypeid, &typ1len, &typ1byval, &typ1align);
		get_typlenbyvalalign(targettypeid, &typ2len, &typ2byval, &typ2align);
		if (typ1len != typ2len ||
			typ1byval != typ2byval ||
			typ1align != typ2align)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
					 errmsg("source and target data types are not physically compatible")));
	}

	/* convert CoercionContext enum to char value for castcontext */
	switch (stmt->context)
	{
		case COERCION_IMPLICIT:
			castcontext = COERCION_CODE_IMPLICIT;
			break;
		case COERCION_ASSIGNMENT:
			castcontext = COERCION_CODE_ASSIGNMENT;
			break;
		case COERCION_EXPLICIT:
			castcontext = COERCION_CODE_EXPLICIT;
			break;
		default:
			elog(ERROR, "unrecognized CoercionContext: %d", stmt->context);
			castcontext = 0;	/* keep compiler quiet */
			break;
	}

	relation = heap_openr(CastRelationName, RowExclusiveLock);

	/*
	 * Check for duplicate.  This is just to give a friendly error
	 * message, the unique index would catch it anyway (so no need to
	 * sweat about race conditions).
	 */
	tuple = SearchSysCache(CASTSOURCETARGET,
						   ObjectIdGetDatum(sourcetypeid),
						   ObjectIdGetDatum(targettypeid),
						   0, 0);
	if (HeapTupleIsValid(tuple))
		ereport(ERROR,
				(errcode(ERRCODE_DUPLICATE_OBJECT),
				 errmsg("cast from type %s to type %s already exists",
						TypeNameToString(stmt->sourcetype),
						TypeNameToString(stmt->targettype))));

	/* ready to go */
	values[Anum_pg_cast_castsource - 1] = ObjectIdGetDatum(sourcetypeid);
	values[Anum_pg_cast_casttarget - 1] = ObjectIdGetDatum(targettypeid);
	values[Anum_pg_cast_castfunc - 1] = ObjectIdGetDatum(funcid);
	values[Anum_pg_cast_castcontext - 1] = CharGetDatum(castcontext);

	MemSet(nulls, ' ', Natts_pg_cast);

	tuple = heap_formtuple(RelationGetDescr(relation), values, nulls);

	simple_heap_insert(relation, tuple);

	CatalogUpdateIndexes(relation, tuple);

	/* make dependency entries */
	myself.classId = RelationGetRelid(relation);
	myself.objectId = HeapTupleGetOid(tuple);
	myself.objectSubId = 0;

	/* dependency on source type */
	referenced.classId = RelOid_pg_type;
	referenced.objectId = sourcetypeid;
	referenced.objectSubId = 0;
	recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);

	/* dependency on target type */
	referenced.classId = RelOid_pg_type;
	referenced.objectId = targettypeid;
	referenced.objectSubId = 0;
	recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);

	/* dependency on function */
	if (OidIsValid(funcid))
	{
		referenced.classId = RelOid_pg_proc;
		referenced.objectId = funcid;
		referenced.objectSubId = 0;
		recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
	}

	heap_freetuple(tuple);

	heap_close(relation, RowExclusiveLock);
}



/*
 * DROP CAST
 */
void
DropCast(DropCastStmt *stmt)
{
	Oid			sourcetypeid;
	Oid			targettypeid;
	HeapTuple	tuple;
	ObjectAddress object;

	sourcetypeid = LookupTypeName(stmt->sourcetype);
	if (!OidIsValid(sourcetypeid))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("source data type %s does not exist",
						TypeNameToString(stmt->sourcetype))));

	targettypeid = LookupTypeName(stmt->targettype);
	if (!OidIsValid(targettypeid))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("target data type %s does not exist",
						TypeNameToString(stmt->targettype))));

	tuple = SearchSysCache(CASTSOURCETARGET,
						   ObjectIdGetDatum(sourcetypeid),
						   ObjectIdGetDatum(targettypeid),
						   0, 0);
	if (!HeapTupleIsValid(tuple))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("cast from type %s to type %s does not exist",
						TypeNameToString(stmt->sourcetype),
						TypeNameToString(stmt->targettype))));

	/* Permission check */
	if (!pg_type_ownercheck(sourcetypeid, GetUserId())
		&& !pg_type_ownercheck(targettypeid, GetUserId()))
		ereport(ERROR,
				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
				 errmsg("must be owner of type %s or type %s",
						TypeNameToString(stmt->sourcetype),
						TypeNameToString(stmt->targettype))));

	/*
	 * Do the deletion
	 */
	object.classId = get_system_catalog_relid(CastRelationName);
	object.objectId = HeapTupleGetOid(tuple);
	object.objectSubId = 0;

	ReleaseSysCache(tuple);

	performDeletion(&object, stmt->behavior);
}


void
DropCastById(Oid castOid)
{
	Relation	relation;
	ScanKeyData scankey;
	SysScanDesc scan;
	HeapTuple	tuple;

	relation = heap_openr(CastRelationName, RowExclusiveLock);

	ScanKeyEntryInitialize(&scankey, 0x0,
						   ObjectIdAttributeNumber,
						   F_OIDEQ,
						   ObjectIdGetDatum(castOid));
	scan = systable_beginscan(relation, CastOidIndex, true,
							  SnapshotNow, 1, &scankey);

	tuple = systable_getnext(scan);
	if (!HeapTupleIsValid(tuple))
		elog(ERROR, "could not find tuple for cast %u", castOid);
	simple_heap_delete(relation, &tuple->t_self);

	systable_endscan(scan);
	heap_close(relation, RowExclusiveLock);
}