Change many routines to return ObjectAddress rather than OID

The changed routines are mostly those that can be directly called by
ProcessUtilitySlow; the intention is to make the affected object
information more precise, in support for future event trigger changes.
Originally it was envisioned that the OID of the affected object would
be enough, and in most cases that is correct, but upon actually
implementing the event trigger changes it turned out that ObjectAddress
is more widely useful.

Additionally, some command execution routines grew an output argument
that's an object address which provides further info about the executed
command.  To wit:

* for ALTER DOMAIN / ADD CONSTRAINT, it corresponds to the address of
  the new constraint

* for ALTER OBJECT / SET SCHEMA, it corresponds to the address of the
  schema that originally contained the object.

* for ALTER EXTENSION {ADD, DROP} OBJECT, it corresponds to the address
  of the object added to or dropped from the extension.

There's no user-visible change in this commit, and no functional change
either.

Discussion: 20150218213255.GC6717@tamriel.snowman.net
Reviewed-By: Stephen Frost, Andres Freund

src/backend/commands/foreigncmds.c

@@ -292,12 +292,13 @@ AlterForeignDataWrapperOwner_internal(Relation rel, HeapTuple tup, Oid newOwnerI
  *
  * Note restrictions in the "_internal" function, above.
  */
-Oid
+ObjectAddress
 AlterForeignDataWrapperOwner(const char *name, Oid newOwnerId)
 {
 	Oid			fdwId;
 	HeapTuple	tup;
 	Relation	rel;
+	ObjectAddress address;
 
 	rel = heap_open(ForeignDataWrapperRelationId, RowExclusiveLock);
 
@@ -312,11 +313,13 @@ AlterForeignDataWrapperOwner(const char *name, Oid newOwnerId)
 
 	AlterForeignDataWrapperOwner_internal(rel, tup, newOwnerId);
 
+	ObjectAddressSet(address, ForeignDataWrapperRelationId, fdwId);
+
 	heap_freetuple(tup);
 
 	heap_close(rel, RowExclusiveLock);
 
-	return fdwId;
+	return address;
 }
 
 /*
@@ -427,12 +430,13 @@ AlterForeignServerOwner_internal(Relation rel, HeapTuple tup, Oid newOwnerId)
 /*
  * Change foreign server owner -- by name
  */
-Oid
+ObjectAddress
 AlterForeignServerOwner(const char *name, Oid newOwnerId)
 {
 	Oid			servOid;
 	HeapTuple	tup;
 	Relation	rel;
+	ObjectAddress address;
 
 	rel = heap_open(ForeignServerRelationId, RowExclusiveLock);
 
@@ -447,11 +451,13 @@ AlterForeignServerOwner(const char *name, Oid newOwnerId)
 
 	AlterForeignServerOwner_internal(rel, tup, newOwnerId);
 
+	ObjectAddressSet(address, ForeignServerRelationId, servOid);
+
 	heap_freetuple(tup);
 
 	heap_close(rel, RowExclusiveLock);
 
-	return servOid;
+	return address;
 }
 
 /*
@@ -569,7 +575,7 @@ parse_func_options(List *func_options,
 /*
  * Create a foreign-data wrapper
  */
-Oid
+ObjectAddress
 CreateForeignDataWrapper(CreateFdwStmt *stmt)
 {
 	Relation	rel;
@@ -676,14 +682,14 @@ CreateForeignDataWrapper(CreateFdwStmt *stmt)
 
 	heap_close(rel, RowExclusiveLock);
 
-	return fdwId;
+	return myself;
 }
 
 
 /*
  * Alter foreign-data wrapper
  */
-Oid
+ObjectAddress
 AlterForeignDataWrapper(AlterFdwStmt *stmt)
 {
 	Relation	rel;
@@ -699,6 +705,7 @@ AlterForeignDataWrapper(AlterFdwStmt *stmt)
 	bool		validator_given;
 	Oid			fdwhandler;
 	Oid			fdwvalidator;
+	ObjectAddress myself;
 
 	rel = heap_open(ForeignDataWrapperRelationId, RowExclusiveLock);
 
@@ -801,10 +808,11 @@ AlterForeignDataWrapper(AlterFdwStmt *stmt)
 
 	heap_freetuple(tp);
 
+	ObjectAddressSet(myself, ForeignDataWrapperRelationId, fdwId);
+
 	/* Update function dependencies if we changed them */
 	if (handler_given || validator_given)
 	{
-		ObjectAddress myself;
 		ObjectAddress referenced;
 
 		/*
@@ -817,9 +825,6 @@ AlterForeignDataWrapper(AlterFdwStmt *stmt)
 										DEPENDENCY_NORMAL);
 
 		/* And build new ones. */
-		myself.classId = ForeignDataWrapperRelationId;
-		myself.objectId = fdwId;
-		myself.objectSubId = 0;
 
 		if (OidIsValid(fdwhandler))
 		{
@@ -842,7 +847,7 @@ AlterForeignDataWrapper(AlterFdwStmt *stmt)
 
 	heap_close(rel, RowExclusiveLock);
 
-	return fdwId;
+	return myself;
 }
 
 
@@ -873,7 +878,7 @@ RemoveForeignDataWrapperById(Oid fdwId)
 /*
  * Create a foreign server
  */
-Oid
+ObjectAddress
 CreateForeignServer(CreateForeignServerStmt *stmt)
 {
 	Relation	rel;
@@ -979,14 +984,14 @@ CreateForeignServer(CreateForeignServerStmt *stmt)
 
 	heap_close(rel, RowExclusiveLock);
 
-	return srvId;
+	return myself;
 }
 
 
 /*
  * Alter foreign server
  */
-Oid
+ObjectAddress
 AlterForeignServer(AlterForeignServerStmt *stmt)
 {
 	Relation	rel;
@@ -996,6 +1001,7 @@ AlterForeignServer(AlterForeignServerStmt *stmt)
 	bool		repl_repl[Natts_pg_foreign_server];
 	Oid			srvId;
 	Form_pg_foreign_server srvForm;
+	ObjectAddress address;
 
 	rel = heap_open(ForeignServerRelationId, RowExclusiveLock);
 
@@ -1072,11 +1078,13 @@ AlterForeignServer(AlterForeignServerStmt *stmt)
 
 	InvokeObjectPostAlterHook(ForeignServerRelationId, srvId, 0);
 
+	ObjectAddressSet(address, ForeignServerRelationId, srvId);
+
 	heap_freetuple(tp);
 
 	heap_close(rel, RowExclusiveLock);
 
-	return srvId;
+	return address;
 }
 
 
@@ -1134,7 +1142,7 @@ user_mapping_ddl_aclcheck(Oid umuserid, Oid serverid, const char *servername)
 /*
  * Create user mapping
  */
-Oid
+ObjectAddress
 CreateUserMapping(CreateUserMappingStmt *stmt)
 {
 	Relation	rel;
@@ -1225,14 +1233,14 @@ CreateUserMapping(CreateUserMappingStmt *stmt)
 
 	heap_close(rel, RowExclusiveLock);
 
-	return umId;
+	return myself;
 }
 
 
 /*
  * Alter user mapping
  */
-Oid
+ObjectAddress
 AlterUserMapping(AlterUserMappingStmt *stmt)
 {
 	Relation	rel;
@@ -1243,6 +1251,7 @@ AlterUserMapping(AlterUserMappingStmt *stmt)
 	Oid			useId;
 	Oid			umId;
 	ForeignServer *srv;
+	ObjectAddress address;
 
 	rel = heap_open(UserMappingRelationId, RowExclusiveLock);
 
@@ -1309,11 +1318,13 @@ AlterUserMapping(AlterUserMappingStmt *stmt)
 	simple_heap_update(rel, &tp->t_self, tp);
 	CatalogUpdateIndexes(rel, tp);
 
+	ObjectAddressSet(address, UserMappingRelationId, umId);
+
 	heap_freetuple(tp);
 
 	heap_close(rel, RowExclusiveLock);
 
-	return umId;
+	return address;
 }