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().

4 files changed, 18 insertions, 12 deletions

diff --git a/src/include/catalog/pg_inherits.h b/src/include/catalog/pg_inherits.h
index 57959b5b2ff..42c3811ef3e 100644
--- a/src/include/catalog/pg_inherits.h
+++ b/src/include/catalog/pg_inherits.h
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_inherits.h,v 1.26 2009/01/01 17:23:57 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_inherits.h,v 1.27 2009/05/12 00:56:05 tgl Exp $
  *
  * NOTES
  *	  the genbki.sh script reads this file and generates .bki
@@ -20,6 +20,7 @@
 #define PG_INHERITS_H
 
 #include "catalog/genbki.h"
+#include "nodes/pg_list.h"
 
 /* ----------------
  *		pg_inherits definition.  cpp turns this into
@@ -51,4 +52,17 @@ typedef FormData_pg_inherits *Form_pg_inherits;
 #define Anum_pg_inherits_inhparent		2
 #define Anum_pg_inherits_inhseqno		3
 
+/* ----------------
+ *		pg_inherits has no initial contents
+ * ----------------
+ */
+
+/*
+ * prototypes for functions in pg_inherits.c
+ */
+extern List *find_inheritance_children(Oid parentrelId);
+extern List *find_all_inheritors(Oid parentrelId);
+extern bool has_subclass(Oid relationId);
+extern bool typeInheritsFrom(Oid subclassTypeId, Oid superclassTypeId);
+
 #endif   /* PG_INHERITS_H */
diff --git a/src/include/optimizer/plancat.h b/src/include/optimizer/plancat.h
index bc3b63e374d..e2d2b00d053 100644
--- a/src/include/optimizer/plancat.h
+++ b/src/include/optimizer/plancat.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/optimizer/plancat.h,v 1.52 2009/01/01 17:24:00 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/plancat.h,v 1.53 2009/05/12 00:56:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -36,10 +36,6 @@ extern bool relation_excluded_by_constraints(PlannerInfo *root,
 
 extern List *build_physical_tlist(PlannerInfo *root, RelOptInfo *rel);
 
-extern List *find_inheritance_children(Oid inhparent);
-
-extern bool has_subclass(Oid relationId);
-
 extern bool has_unique_index(RelOptInfo *rel, AttrNumber attno);
 
 extern Selectivity restriction_selectivity(PlannerInfo *root,
diff --git a/src/include/optimizer/prep.h b/src/include/optimizer/prep.h
index 58b8c924618..e8dfb1e28fb 100644
--- a/src/include/optimizer/prep.h
+++ b/src/include/optimizer/prep.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/optimizer/prep.h,v 1.65 2009/04/28 21:31:16 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/prep.h,v 1.66 2009/05/12 00:56:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -46,8 +46,6 @@ extern List *preprocess_targetlist(PlannerInfo *root, List *tlist);
 extern Plan *plan_set_operations(PlannerInfo *root, double tuple_fraction,
 					List **sortClauses);
 
-extern List *find_all_inheritors(Oid parentrel);
-
 extern void expand_inherited_tables(PlannerInfo *root);
 
 extern Node *adjust_appendrel_attrs(Node *node, AppendRelInfo *appinfo);
diff --git a/src/include/parser/parse_func.h b/src/include/parser/parse_func.h
index 710d703e0d5..7905f96e86c 100644
--- a/src/include/parser/parse_func.h
+++ b/src/include/parser/parse_func.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/parser/parse_func.h,v 1.64 2009/01/01 17:24:00 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/parser/parse_func.h,v 1.65 2009/05/12 00:56:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -63,8 +63,6 @@ extern FuncCandidateList func_select_candidate(int nargs,
 					  Oid *input_typeids,
 					  FuncCandidateList candidates);
 
-extern bool typeInheritsFrom(Oid subclassTypeId, Oid superclassTypeId);
-
 extern void make_fn_arguments(ParseState *pstate,
 				  List *fargs,
 				  Oid *actual_arg_types,