comment.c

来自「PostgreSQL7.4.6 for Linux」· C语言 代码 · 共 916 行 · 第 1/2 页

	CreateComments(oid, RelOid_pg_database, 0, comment);
}

/*
 * CommentNamespace --
 *
 * This routine is used to add/drop any user-comments a user might
 * have regarding the specified namespace. The routine will check
 * security for owner permissions, and, if successful, will then
 * attempt to find the oid of the namespace specified. Once found,
 * a comment is added/dropped using the CreateComments() routine.
 */
static void
CommentNamespace(List *qualname, char *comment)
{
	Oid			oid;
	Oid			classoid;
	char	   *namespace;

	if (length(qualname) != 1)
		ereport(ERROR,
				(errcode(ERRCODE_SYNTAX_ERROR),
				 errmsg("schema name may not be qualified")));
	namespace = strVal(lfirst(qualname));

	oid = GetSysCacheOid(NAMESPACENAME,
						 CStringGetDatum(namespace),
						 0, 0, 0);
	if (!OidIsValid(oid))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_SCHEMA),
				 errmsg("schema \"%s\" does not exist", namespace)));

	/* Check object security */
	if (!pg_namespace_ownercheck(oid, GetUserId()))
		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_NAMESPACE,
					   namespace);

	/* pg_namespace doesn't have a hard-coded OID, so must look it up */
	classoid = get_system_catalog_relid(NamespaceRelationName);

	/* Call CreateComments() to create/drop the comments */
	CreateComments(oid, classoid, 0, comment);
}

/*
 * CommentRule --
 *
 * This routine is used to add/drop any user-comments a user might
 * have regarding a specified RULE. The rule for commenting is determined by
 * both its name and the relation to which it refers. The arguments to this
 * function are the rule name and relation name (merged into a qualified
 * name), and the comment to add/drop.
 *
 * Before PG 7.3, rules had unique names across the whole database, and so
 * the syntax was just COMMENT ON RULE rulename, with no relation name.
 * For purposes of backwards compatibility, we support that as long as there
 * is only one rule by the specified name in the database.
 */
static void
CommentRule(List *qualname, char *comment)
{
	int			nnames;
	List	   *relname;
	char	   *rulename;
	RangeVar   *rel;
	Relation	relation;
	HeapTuple	tuple;
	Oid			reloid;
	Oid			ruleoid;
	Oid			classoid;
	AclResult	aclcheck;

	/* Separate relname and trig name */
	nnames = length(qualname);
	if (nnames == 1)
	{
		/* Old-style: only a rule name is given */
		Relation	RewriteRelation;
		HeapScanDesc scanDesc;
		ScanKeyData scanKeyData;

		rulename = strVal(lfirst(qualname));

		/* Search pg_rewrite for such a rule */
		ScanKeyEntryInitialize(&scanKeyData,
							   0,
							   Anum_pg_rewrite_rulename,
							   F_NAMEEQ,
							   PointerGetDatum(rulename));

		RewriteRelation = heap_openr(RewriteRelationName, AccessShareLock);
		scanDesc = heap_beginscan(RewriteRelation, SnapshotNow,
								  1, &scanKeyData);

		tuple = heap_getnext(scanDesc, ForwardScanDirection);
		if (HeapTupleIsValid(tuple))
		{
			reloid = ((Form_pg_rewrite) GETSTRUCT(tuple))->ev_class;
			ruleoid = HeapTupleGetOid(tuple);
		}
		else
		{
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_OBJECT),
					 errmsg("rule \"%s\" does not exist", rulename)));
			reloid = ruleoid = 0;		/* keep compiler quiet */
		}

		if (HeapTupleIsValid(tuple = heap_getnext(scanDesc,
												  ForwardScanDirection)))
			ereport(ERROR,
					(errcode(ERRCODE_DUPLICATE_OBJECT),
					 errmsg("there are multiple rules named \"%s\"", rulename),
			errhint("Specify a relation name as well as a rule name.")));

		heap_endscan(scanDesc);
		heap_close(RewriteRelation, AccessShareLock);

		/* Open the owning relation to ensure it won't go away meanwhile */
		relation = heap_open(reloid, AccessShareLock);
	}
	else
	{
		/* New-style: rule and relname both provided */
		Assert(nnames >= 2);
		relname = ltruncate(nnames - 1, listCopy(qualname));
		rulename = strVal(llast(qualname));

		/* Open the owning relation to ensure it won't go away meanwhile */
		rel = makeRangeVarFromNameList(relname);
		relation = heap_openrv(rel, AccessShareLock);
		reloid = RelationGetRelid(relation);

		/* Find the rule's pg_rewrite tuple, get its OID */
		tuple = SearchSysCache(RULERELNAME,
							   ObjectIdGetDatum(reloid),
							   PointerGetDatum(rulename),
							   0, 0);
		if (!HeapTupleIsValid(tuple))
			elog(ERROR, "cache lookup failed for rule \"%s\"", rulename);
		Assert(reloid == ((Form_pg_rewrite) GETSTRUCT(tuple))->ev_class);
		ruleoid = HeapTupleGetOid(tuple);
		ReleaseSysCache(tuple);
	}

	/* Check object security */
	aclcheck = pg_class_aclcheck(reloid, GetUserId(), ACL_RULE);
	if (aclcheck != ACLCHECK_OK)
		aclcheck_error(aclcheck, ACL_KIND_CLASS,
					   get_rel_name(reloid));

	/* pg_rewrite doesn't have a hard-coded OID, so must look it up */
	classoid = get_system_catalog_relid(RewriteRelationName);

	/* Call CreateComments() to create/drop the comments */
	CreateComments(ruleoid, classoid, 0, comment);

	heap_close(relation, NoLock);
}

/*
 * CommentType --
 *
 * This routine is used to add/drop any user-comments a user might
 * have regarding a TYPE. The type is specified by name
 * and, if found, and the user has appropriate permissions, a
 * comment will be added/dropped using the CreateComments() routine.
 * The type's name and the comments are the parameters to this routine.
 */
static void
CommentType(List *typename, char *comment)
{
	TypeName   *tname;
	Oid			oid;

	/* XXX a bit of a crock; should accept TypeName in COMMENT syntax */
	tname = makeNode(TypeName);
	tname->names = typename;
	tname->typmod = -1;

	/* Find the type's oid */

	oid = typenameTypeId(tname);

	/* Check object security */

	if (!pg_type_ownercheck(oid, GetUserId()))
		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_TYPE,
					   TypeNameToString(tname));

	/* Call CreateComments() to create/drop the comments */

	CreateComments(oid, RelOid_pg_type, 0, comment);
}

/*
 * CommentAggregate --
 *
 * This routine is used to allow a user to provide comments on an
 * aggregate function. The aggregate function is determined by both
 * its name and its argument type, which, with the comments are
 * the three parameters handed to this routine.
 */
static void
CommentAggregate(List *aggregate, List *arguments, char *comment)
{
	TypeName   *aggtype = (TypeName *) lfirst(arguments);
	Oid			baseoid,
				oid;

	/* First, attempt to determine the base aggregate oid */
	if (aggtype)
		baseoid = typenameTypeId(aggtype);
	else
		baseoid = ANYOID;

	/* Now, attempt to find the actual tuple in pg_proc */

	oid = find_aggregate_func(aggregate, baseoid, false);

	/* Next, validate the user's attempt to comment */

	if (!pg_proc_ownercheck(oid, GetUserId()))
		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_PROC,
					   NameListToString(aggregate));

	/* Call CreateComments() to create/drop the comments */

	CreateComments(oid, RelOid_pg_proc, 0, comment);
}

/*
 * CommentProc --
 *
 * This routine is used to allow a user to provide comments on an
 * procedure (function). The procedure is determined by both
 * its name and its argument list. The argument list is expected to
 * be a series of parsed nodes pointed to by a List object. If the
 * comments string is empty, the associated comment is dropped.
 */
static void
CommentProc(List *function, List *arguments, char *comment)
{
	Oid			oid;

	/* Look up the procedure */

	oid = LookupFuncNameTypeNames(function, arguments, false);

	/* Now, validate the user's ability to comment on this function */

	if (!pg_proc_ownercheck(oid, GetUserId()))
		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_PROC,
					   NameListToString(function));

	/* Call CreateComments() to create/drop the comments */

	CreateComments(oid, RelOid_pg_proc, 0, comment);
}

/*
 * CommentOperator --
 *
 * This routine is used to allow a user to provide comments on an
 * operator. The operator for commenting is determined by both
 * its name and its argument list which defines the left and right
 * hand types the operator will operate on. The argument list is
 * expected to be a couple of parse nodes pointed to be a List
 * object.
 */
static void
CommentOperator(List *opername, List *arguments, char *comment)
{
	TypeName   *typenode1 = (TypeName *) lfirst(arguments);
	TypeName   *typenode2 = (TypeName *) lsecond(arguments);
	Oid			oid;
	Oid			classoid;

	/* Look up the operator */
	oid = LookupOperNameTypeNames(opername, typenode1, typenode2, false);

	/* Valid user's ability to comment on this operator */
	if (!pg_oper_ownercheck(oid, GetUserId()))
		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_OPER,
					   NameListToString(opername));

	/* pg_operator doesn't have a hard-coded OID, so must look it up */
	classoid = get_system_catalog_relid(OperatorRelationName);

	/* Call CreateComments() to create/drop the comments */
	CreateComments(oid, classoid, 0, comment);
}

/*
 * CommentTrigger --
 *
 * This routine is used to allow a user to provide comments on a
 * trigger event. The trigger for commenting is determined by both
 * its name and the relation to which it refers. The arguments to this
 * function are the trigger name and relation name (merged into a qualified
 * name), and the comment to add/drop.
 */
static void
CommentTrigger(List *qualname, char *comment)
{
	int			nnames;
	List	   *relname;
	char	   *trigname;
	RangeVar   *rel;
	Relation	pg_trigger,
				relation;
	HeapTuple	triggertuple;
	SysScanDesc scan;
	ScanKeyData entry[2];
	Oid			oid;

	/* Separate relname and trig name */
	nnames = length(qualname);
	if (nnames < 2)				/* parser messed up */
		elog(ERROR, "must specify relation and trigger");
	relname = ltruncate(nnames - 1, listCopy(qualname));
	trigname = strVal(llast(qualname));

	/* Open the owning relation to ensure it won't go away meanwhile */
	rel = makeRangeVarFromNameList(relname);
	relation = heap_openrv(rel, AccessShareLock);

	/* Check object security */

	if (!pg_class_ownercheck(RelationGetRelid(relation), GetUserId()))
		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
					   RelationGetRelationName(relation));

	/*
	 * Fetch the trigger tuple from pg_trigger.  There can be only one
	 * because of the unique index.
	 */
	pg_trigger = heap_openr(TriggerRelationName, AccessShareLock);
	ScanKeyEntryInitialize(&entry[0], 0x0,
						   Anum_pg_trigger_tgrelid,
						   F_OIDEQ,
						   ObjectIdGetDatum(RelationGetRelid(relation)));
	ScanKeyEntryInitialize(&entry[1], 0x0,
						   Anum_pg_trigger_tgname,
						   F_NAMEEQ,
						   CStringGetDatum(trigname));
	scan = systable_beginscan(pg_trigger, TriggerRelidNameIndex, true,
							  SnapshotNow, 2, entry);
	triggertuple = systable_getnext(scan);

	/* If no trigger exists for the relation specified, notify user */

	if (!HeapTupleIsValid(triggertuple))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
			  errmsg("trigger \"%s\" for table \"%s\" does not exist",
					 trigname, RelationGetRelationName(relation))));

	oid = HeapTupleGetOid(triggertuple);

	systable_endscan(scan);

	/* Create the comment with the pg_trigger oid */

	CreateComments(oid, RelationGetRelid(pg_trigger), 0, comment);

	/* Done, but hold lock on relation */

	heap_close(pg_trigger, AccessShareLock);
	heap_close(relation, NoLock);
}


/*
 * CommentConstraint --
 *
 * Enable commenting on constraints held within the pg_constraint
 * table.  A qualified name is required as constraint names are
 * unique per relation.
 */
static void
CommentConstraint(List *qualname, char *comment)
{
	int			nnames;
	List	   *relName;
	char	   *conName;
	RangeVar   *rel;
	Relation	pg_constraint,
				relation;
	HeapTuple	tuple;
	SysScanDesc scan;
	ScanKeyData skey[1];
	Oid			conOid = InvalidOid;

	/* Separate relname and constraint name */
	nnames = length(qualname);
	if (nnames < 2)				/* parser messed up */
		elog(ERROR, "must specify relation and constraint");
	relName = ltruncate(nnames - 1, listCopy(qualname));
	conName = strVal(llast(qualname));

	/* Open the owning relation to ensure it won't go away meanwhile */
	rel = makeRangeVarFromNameList(relName);
	relation = heap_openrv(rel, AccessShareLock);

	/* Check object security */

	if (!pg_class_ownercheck(RelationGetRelid(relation), GetUserId()))
		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
					   RelationGetRelationName(relation));

	/*
	 * Fetch the constraint tuple from pg_constraint.  There may be more
	 * than one match, because constraints are not required to have unique
	 * names; if so, error out.
	 */
	pg_constraint = heap_openr(ConstraintRelationName, AccessShareLock);

	ScanKeyEntryInitialize(&skey[0], 0x0,
						   Anum_pg_constraint_conrelid, F_OIDEQ,
						   ObjectIdGetDatum(RelationGetRelid(relation)));

	scan = systable_beginscan(pg_constraint, ConstraintRelidIndex, true,
							  SnapshotNow, 1, skey);

	while (HeapTupleIsValid(tuple = systable_getnext(scan)))
	{
		Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(tuple);

		if (strcmp(NameStr(con->conname), conName) == 0)
		{
			if (OidIsValid(conOid))
				ereport(ERROR,
						(errcode(ERRCODE_DUPLICATE_OBJECT),
						 errmsg("table \"%s\" has multiple constraints named \"%s\"",
						   RelationGetRelationName(relation), conName)));
			conOid = HeapTupleGetOid(tuple);
		}
	}

	systable_endscan(scan);

	/* If no constraint exists for the relation specified, notify user */
	if (!OidIsValid(conOid))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
		   errmsg("constraint \"%s\" for table \"%s\" does not exist",
				  conName, RelationGetRelationName(relation))));

	/* Create the comment with the pg_constraint oid */
	CreateComments(conOid, RelationGetRelid(pg_constraint), 0, comment);

	/* Done, but hold lock on relation */
	heap_close(pg_constraint, AccessShareLock);
	heap_close(relation, NoLock);
}