Fold FindConversion() into FindConversionByName() and remove ACL check.

All callers of FindConversionByName() already do suitable permissions
checking already apart from this function, but this is not just dead
code removal: the unnecessary permissions check can actually lead to
spurious failures - there's no reason why inability to execute the
underlying function should prohibit renaming the conversion, for example.
(The error messages in these cases were also rather poor:
FindConversion would return InvalidOid, eventually leading to a complaint
that the conversion "did not exist", which was not correct.)

KaiGai Kohei

src/backend/catalog/namespace.c

@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/namespace.c,v 1.121 2010/01/02 16:57:36 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/namespace.c,v 1.122 2010/02/02 18:52:33 rhaas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2836,7 +2836,10 @@ FindConversionByName(List *name)
 	{
 		/* use exact schema given */
 		namespaceId = LookupExplicitNamespace(schemaname);
-		return FindConversion(conversion_name, namespaceId);
+		return GetSysCacheOid(CONNAMENSP,
+							  PointerGetDatum(conversion_name),
+							  ObjectIdGetDatum(namespaceId),
+							  0, 0);
 	}
 	else
 	{
@@ -2850,7 +2853,10 @@ FindConversionByName(List *name)
 			if (namespaceId == myTempNamespace)
 				continue;		/* do not look in temp namespace */
 
-			conoid = FindConversion(conversion_name, namespaceId);
+			conoid = GetSysCacheOid(CONNAMENSP,
+									PointerGetDatum(conversion_name),
+									ObjectIdGetDatum(namespaceId),
+									0, 0);
 			if (OidIsValid(conoid))
 				return conoid;
 		}

src/backend/catalog/pg_conversion.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/pg_conversion.c,v 1.48 2010/01/02 16:57:36 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/pg_conversion.c,v 1.49 2010/02/02 18:52:33 rhaas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -209,38 +209,3 @@ FindDefaultConversion(Oid name_space, int32 for_encoding, int32 to_encoding)
 	ReleaseSysCacheList(catlist);
 	return proc;
 }
-
-/*
- * FindConversion
- *
- * Find conversion by namespace and conversion name.
- * Returns conversion OID.
- */
-Oid
-FindConversion(const char *conname, Oid connamespace)
-{
-	HeapTuple	tuple;
-	Oid			procoid;
-	Oid			conoid;
-	AclResult	aclresult;
-
-	/* search pg_conversion by connamespace and conversion name */
-	tuple = SearchSysCache(CONNAMENSP,
-						   PointerGetDatum(conname),
-						   ObjectIdGetDatum(connamespace),
-						   0, 0);
-	if (!HeapTupleIsValid(tuple))
-		return InvalidOid;
-
-	procoid = ((Form_pg_conversion) GETSTRUCT(tuple))->conproc;
-	conoid = HeapTupleGetOid(tuple);
-
-	ReleaseSysCache(tuple);
-
-	/* Check we have execute rights for the function */
-	aclresult = pg_proc_aclcheck(procoid, GetUserId(), ACL_EXECUTE);
-	if (aclresult != ACLCHECK_OK)
-		return InvalidOid;
-
-	return conoid;
-}

src/include/catalog/pg_conversion_fn.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_conversion_fn.h,v 1.5 2010/01/02 16:58:01 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_conversion_fn.h,v 1.6 2010/02/02 18:52:33 rhaas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -19,7 +19,6 @@ extern Oid ConversionCreate(const char *conname, Oid connamespace,
 				 int32 conforencoding, int32 contoencoding,
 				 Oid conproc, bool def);
 extern void RemoveConversionById(Oid conversionOid);
-extern Oid	FindConversion(const char *conname, Oid connamespace);
 extern Oid	FindDefaultConversion(Oid connamespace, int32 for_encoding, int32 to_encoding);
 
 #endif   /* PG_CONVERSION_FN_H */