Move renametrig() from tablecmds.c to trigger.c --- if we're going to

divide backend/commands by object type, let's try to pay at least
minimal attention to respecting that structure, eh?  Also reorder the
contents of tablecmds.c; it seems odd to me to put ALTER commands before
creation/deletion commands.

src/backend/commands/trigger.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/trigger.c,v 1.114 2002/04/19 16:36:08 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/trigger.c,v 1.115 2002/04/26 19:29:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -503,6 +503,123 @@ RelationRemoveTriggers(Relation rel)
 	heap_close(tgrel, RowExclusiveLock);
 }
 
+/*
+ *		renametrig		- changes the name of a trigger on a relation
+ *
+ *		trigger name is changed in trigger catalog.
+ *		No record of the previous name is kept.
+ *
+ *		get proper relrelation from relation catalog (if not arg)
+ *		scan trigger catalog
+ *				for name conflict (within rel)
+ *				for original trigger (if not arg)
+ *		modify tgname in trigger tuple
+ *		insert modified trigger in trigger catalog
+ *		delete original trigger from trigger catalog
+ */
+void
+renametrig(Oid relid,
+		   const char *oldname,
+		   const char *newname)
+{
+	Relation	targetrel;
+	Relation	tgrel;
+	HeapTuple	tuple;
+	SysScanDesc	tgscan;
+	ScanKeyData key;
+	bool		found = FALSE;
+	Relation	idescs[Num_pg_trigger_indices];
+
+	/*
+	 * Grab an exclusive lock on the target table, which we will NOT
+	 * release until end of transaction.
+	 */
+	targetrel = heap_open(relid, AccessExclusiveLock);
+
+	/*
+	 * Scan pg_trigger twice for existing triggers on relation.  We do this in
+	 * order to ensure a trigger does not exist with newname (The unique index
+	 * on tgrelid/tgname would complain anyway) and to ensure a trigger does
+	 * exist with oldname.
+	 *
+	 * NOTE that this is cool only because we have AccessExclusiveLock on the
+	 * relation, so the trigger set won't be changing underneath us.
+	 */
+	tgrel = heap_openr(TriggerRelationName, RowExclusiveLock);
+
+	/*
+	 * First pass -- look for name conflict
+	 */
+	ScanKeyEntryInitialize(&key, 0,
+						   Anum_pg_trigger_tgrelid,
+						   F_OIDEQ,
+						   ObjectIdGetDatum(relid));
+	tgscan = systable_beginscan(tgrel, TriggerRelidNameIndex, true,
+								SnapshotNow, 1, &key);
+	while (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
+	{
+		Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple);
+
+		if (namestrcmp(&(pg_trigger->tgname), newname) == 0)
+			elog(ERROR, "renametrig: trigger %s already defined on relation %s",
+				 newname, RelationGetRelationName(targetrel));
+	}
+	systable_endscan(tgscan);
+
+	/*
+	 * Second pass -- look for trigger existing with oldname and update
+	 */
+	ScanKeyEntryInitialize(&key, 0,
+						   Anum_pg_trigger_tgrelid,
+						   F_OIDEQ,
+						   ObjectIdGetDatum(relid));
+	tgscan = systable_beginscan(tgrel, TriggerRelidNameIndex, true,
+								SnapshotNow, 1, &key);
+	while (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
+	{
+		Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple);
+
+		if (namestrcmp(&(pg_trigger->tgname), oldname) == 0)
+		{
+			/*
+			 * Update pg_trigger tuple with new tgname.
+			 * (Scribbling on tuple is OK because it's a copy...)
+			 */
+			namestrcpy(&(pg_trigger->tgname), newname);
+			simple_heap_update(tgrel, &tuple->t_self, tuple);
+
+			/*
+			 * keep system catalog indices current
+			 */
+			CatalogOpenIndices(Num_pg_trigger_indices, Name_pg_trigger_indices, idescs);
+			CatalogIndexInsert(idescs, Num_pg_trigger_indices, tgrel, tuple);
+			CatalogCloseIndices(Num_pg_trigger_indices, idescs);
+
+			/*
+			 * Invalidate relation's relcache entry so that other
+			 * backends (and this one too!) are sent SI message to make them
+			 * rebuild relcache entries.
+			 */
+			CacheInvalidateRelcache(relid);
+
+			found = TRUE;
+			break;
+		}
+	}
+	systable_endscan(tgscan);
+
+	heap_close(tgrel, RowExclusiveLock);
+
+	if (!found)
+		elog(ERROR, "renametrig: trigger %s not defined on relation %s",
+			 oldname, RelationGetRelationName(targetrel));
+
+	/*
+	 * Close rel, but keep exclusive lock!
+	 */
+	heap_close(targetrel, NoLock);
+}
+
 /*
  * Build trigger data to attach to the given relcache entry.
  *

src/backend/commands/user.c

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Header: /cvsroot/pgsql/src/backend/commands/user.c,v 1.96 2002/04/18 21:16:16 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/commands/user.c,v 1.97 2002/04/26 19:29:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -646,7 +646,7 @@ CreateUser(CreateUserStmt *stmt)
 /*
  * ALTER USER
  */
-extern void
+void
 AlterUser(AlterUserStmt *stmt)
 {
 	Datum		new_record[Natts_pg_shadow];

src/include/commands/tablecmds.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: tablecmds.h,v 1.2 2002/04/24 02:48:55 momjian Exp $
+ * $Id: tablecmds.h,v 1.3 2002/04/26 19:29:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -61,8 +61,4 @@ extern void renameatt(Oid relid,
 extern void renamerel(Oid relid,
 		  const char *newrelname);
 
-extern void renametrig(Oid relid,
-		  const char *oldname,
-		  const char *newname);
-
 #endif   /* TABLECMDS_H */

src/include/commands/trigger.h

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: trigger.h,v 1.34 2002/04/01 22:36:13 tgl Exp $
+ * $Id: trigger.h,v 1.35 2002/04/26 19:29:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -105,6 +105,8 @@ extern void CreateTrigger(CreateTrigStmt *stmt);
 extern void DropTrigger(Oid relid, const char *trigname);
 extern void RelationRemoveTriggers(Relation rel);
 
+extern void renametrig(Oid relid, const char *oldname, const char *newname);
+
 extern void RelationBuildTriggers(Relation relation);
 
 extern void FreeTriggerDesc(TriggerDesc *trigdesc);