Do some minor code refactoring in preparation for changing the APIs of

find_inheritance_children() and find_all_inheritors().  I got annoyed that
these are buried inside the planner but mostly used elsewhere.  So, create
a new file catalog/pg_inherits.c and put them there, along with a couple
of other functions that search pg_inherits.

The code that modifies pg_inherits is (still) in tablecmds.c --- it's
kind of entangled with unrelated code that modifies pg_depend and other
stuff, so pulling it out seemed like a bigger change than I wanted to make
right now.  But this file provides a natural home for it if anyone ever
gets around to that.

This commit just moves code around; it doesn't change anything, except
I succumbed to the temptation to make a couple of trivial optimizations
in typeInheritsFrom().

1 files changed, 1 insertions, 97 deletions

diff --git a/src/backend/parser/parse_func.c b/src/backend/parser/parse_func.c
index 91a6f12d662..38008b9cea9 100644
--- a/src/backend/parser/parse_func.c
+++ b/src/backend/parser/parse_func.c
@@ -8,14 +8,12 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_func.c,v 1.213 2009/04/24 16:09:50 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_func.c,v 1.214 2009/05/12 00:56:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
 #include "postgres.h"
 
-#include "access/heapam.h"
-#include "catalog/pg_inherits.h"
 #include "catalog/pg_proc.h"
 #include "catalog/pg_type.h"
 #include "funcapi.h"
@@ -28,10 +26,8 @@
 #include "parser/parse_target.h"
 #include "parser/parse_type.h"
 #include "utils/builtins.h"
-#include "utils/fmgroids.h"
 #include "utils/lsyscache.h"
 #include "utils/syscache.h"
-#include "utils/tqual.h"
 
 
 static Oid	FuncNameAsType(List *funcname);
@@ -1038,98 +1034,6 @@ func_get_detail(List *funcname,
 
 
 /*
- * Given two type OIDs, determine whether the first is a complex type
- * (class type) that inherits from the second.
- */
-bool
-typeInheritsFrom(Oid subclassTypeId, Oid superclassTypeId)
-{
-	bool		result = false;
-	Oid			relid;
-	Relation	inhrel;
-	List	   *visited,
-			   *queue;
-	ListCell   *queue_item;
-
-	if (!ISCOMPLEX(subclassTypeId) || !ISCOMPLEX(superclassTypeId))
-		return false;
-	relid = typeidTypeRelid(subclassTypeId);
-	if (relid == InvalidOid)
-		return false;
-
-	/*
-	 * Begin the search at the relation itself, so add relid to the queue.
-	 */
-	queue = list_make1_oid(relid);
-	visited = NIL;
-
-	inhrel = heap_open(InheritsRelationId, AccessShareLock);
-
-	/*
-	 * Use queue to do a breadth-first traversal of the inheritance graph from
-	 * the relid supplied up to the root.  Notice that we append to the queue
-	 * inside the loop --- this is okay because the foreach() macro doesn't
-	 * advance queue_item until the next loop iteration begins.
-	 */
-	foreach(queue_item, queue)
-	{
-		Oid			this_relid = lfirst_oid(queue_item);
-		ScanKeyData skey;
-		HeapScanDesc inhscan;
-		HeapTuple	inhtup;
-
-		/* If we've seen this relid already, skip it */
-		if (list_member_oid(visited, this_relid))
-			continue;
-
-		/*
-		 * Okay, this is a not-yet-seen relid. Add it to the list of
-		 * already-visited OIDs, then find all the types this relid inherits
-		 * from and add them to the queue. The one exception is we don't add
-		 * the original relation to 'visited'.
-		 */
-		if (queue_item != list_head(queue))
-			visited = lappend_oid(visited, this_relid);
-
-		ScanKeyInit(&skey,
-					Anum_pg_inherits_inhrelid,
-					BTEqualStrategyNumber, F_OIDEQ,
-					ObjectIdGetDatum(this_relid));
-
-		inhscan = heap_beginscan(inhrel, SnapshotNow, 1, &skey);
-
-		while ((inhtup = heap_getnext(inhscan, ForwardScanDirection)) != NULL)
-		{
-			Form_pg_inherits inh = (Form_pg_inherits) GETSTRUCT(inhtup);
-			Oid			inhparent = inh->inhparent;
-
-			/* If this is the target superclass, we're done */
-			if (get_rel_type_id(inhparent) == superclassTypeId)
-			{
-				result = true;
-				break;
-			}
-
-			/* Else add to queue */
-			queue = lappend_oid(queue, inhparent);
-		}
-
-		heap_endscan(inhscan);
-
-		if (result)
-			break;
-	}
-
-	heap_close(inhrel, AccessShareLock);
-
-	list_free(visited);
-	list_free(queue);
-
-	return result;
-}
-
-
-/*
  * make_fn_arguments()
  *
  * Given the actual argument expressions for a function, and the desired