Remove 'func_tlist' from Func expression nodes, likewise 'param_tlist'

from Param nodes, per discussion a few days ago on pghackers.  Add new
expression node type FieldSelect that implements the functionality where
it's actually needed.  Clean up some other unused fields in Func nodes
as well.
NOTE: initdb forced due to change in stored expression trees for rules.

1 files changed, 36 insertions, 46 deletions

diff --git a/src/backend/executor/functions.c b/src/backend/executor/functions.c
index a92811d0342..001feb267ff 100644
--- a/src/backend/executor/functions.c
+++ b/src/backend/executor/functions.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/functions.c,v 1.36 2000/07/12 02:37:03 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/functions.c,v 1.37 2000/08/08 15:41:22 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -47,24 +47,21 @@ static void postquel_end(execution_state *es);
 static void postquel_sub_params(execution_state *es, FunctionCallInfo fcinfo);
 static Datum postquel_execute(execution_state *es,
 							  FunctionCallInfo fcinfo,
-							  FunctionCachePtr fcache,
-							  List *func_tlist);
+							  FunctionCachePtr fcache);
 
 
-Datum
-ProjectAttribute(TupleDesc TD,
-				 TargetEntry *tlist,
-				 HeapTuple tup,
+static Datum
+ProjectAttribute(HeapTuple tup,
+				 AttrNumber	attrno,
+				 TupleDesc TD,
 				 bool *isnullP)
 {
 	Datum		val;
-	Var		   *attrVar = (Var *) tlist->expr;
-	AttrNumber	attrno = attrVar->varattno;
 
 	val = heap_getattr(tup, attrno, TD, isnullP);
 
 	if (*isnullP)
-		return (Datum) 0;
+		return val;
 
 	return datumCopy(val,
 					 TD->attrs[attrno - 1]->attbyval,
@@ -216,39 +213,29 @@ copy_function_result(FunctionCachePtr fcache,
 {
 	TupleTableSlot *funcSlot;
 	TupleDesc	resultTd;
+	HeapTuple	resultTuple;
 	HeapTuple	newTuple;
-	HeapTuple	oldTuple;
 
 	Assert(!TupIsNull(resultSlot));
-	oldTuple = resultSlot->val;
+	resultTuple = resultSlot->val;
 
 	funcSlot = (TupleTableSlot *) fcache->funcSlot;
 
 	if (funcSlot == (TupleTableSlot *) NULL)
 		return resultSlot;
 
-	resultTd = resultSlot->ttc_tupleDescriptor;
-
 	/*
-	 * When the funcSlot is NULL we have to initialize the funcSlot's
+	 * If first time through, we have to initialize the funcSlot's
 	 * tuple descriptor.
 	 */
 	if (TupIsNull(funcSlot))
 	{
-		int			i = 0;
-		TupleDesc	funcTd = funcSlot->ttc_tupleDescriptor;
-
-		while (i < oldTuple->t_data->t_natts)
-		{
-			funcTd->attrs[i] = (Form_pg_attribute) palloc(ATTRIBUTE_TUPLE_SIZE);
-			memmove(funcTd->attrs[i],
-					resultTd->attrs[i],
-					ATTRIBUTE_TUPLE_SIZE);
-			i++;
-		}
+		resultTd = resultSlot->ttc_tupleDescriptor;
+		funcSlot->ttc_tupleDescriptor = CreateTupleDescCopy(resultTd);
+		funcSlot->ttc_descIsNew = true;
 	}
 
-	newTuple = heap_copytuple(oldTuple);
+	newTuple = heap_copytuple(resultTuple);
 
 	return ExecStoreTuple(newTuple, funcSlot, InvalidBuffer, true);
 }
@@ -256,8 +243,7 @@ copy_function_result(FunctionCachePtr fcache,
 static Datum
 postquel_execute(execution_state *es,
 				 FunctionCallInfo fcinfo,
-				 FunctionCachePtr fcache,
-				 List *func_tlist)
+				 FunctionCachePtr fcache)
 {
 	TupleTableSlot *slot;
 	Datum		value;
@@ -305,27 +291,35 @@ postquel_execute(execution_state *es,
 		 * logic and code redundancy here.
 		 */
 		resSlot = copy_function_result(fcache, slot);
-		if (func_tlist != NIL)
-		{
-			TargetEntry *tle = lfirst(func_tlist);
 
-			value = ProjectAttribute(resSlot->ttc_tupleDescriptor,
-									 tle,
-									 resSlot->val,
-									 &fcinfo->isnull);
-		}
-		else
+		/*
+		 * If we are supposed to return a tuple, we return the tuple slot
+		 * pointer converted to Datum.  If we are supposed to return a simple
+		 * value, then project out the first attribute of the result tuple
+		 * (ie, take the first result column of the final SELECT).
+		 */
+		if (fcache->returnsTuple)
 		{
-			/* XXX is this right?  Return whole tuple slot?? */
+			/*
+			 * XXX do we need to remove junk attrs from the result tuple?
+			 * Probably OK to leave them, as long as they are at the end.
+			 */
 			value = PointerGetDatum(resSlot);
 			fcinfo->isnull = false;
 		}
+		else
+		{
+			value = ProjectAttribute(resSlot->val,
+									 1,
+									 resSlot->ttc_tupleDescriptor,
+									 &fcinfo->isnull);
+		}
 
 		/*
 		 * If this is a single valued function we have to end the function
 		 * execution now.
 		 */
-		if (fcache->oneResult)
+		if (!fcache->returnsSet)
 		{
 			postquel_end(es);
 			es->status = F_EXEC_DONE;
@@ -346,7 +340,6 @@ postquel_execute(execution_state *es,
 Datum
 postquel_function(FunctionCallInfo fcinfo,
 				  FunctionCachePtr fcache,
-				  List *func_tlist,
 				  bool *isDone)
 {
 	MemoryContext oldcontext;
@@ -388,10 +381,7 @@ postquel_function(FunctionCallInfo fcinfo,
 	 */
 	while (es != (execution_state *) NULL)
 	{
-		result = postquel_execute(es,
-								  fcinfo,
-								  fcache,
-								  func_tlist);
+		result = postquel_execute(es, fcinfo, fcache);
 		if (es->status != F_EXEC_DONE)
 			break;
 		es = es->next;
@@ -423,7 +413,7 @@ postquel_function(FunctionCallInfo fcinfo,
 		 */
 		*isDone = true;
 		MemoryContextSwitchTo(oldcontext);
-		return (fcache->oneResult) ? result : (Datum) NULL;
+		return (fcache->returnsSet) ? (Datum) NULL : result;
 	}
 
 	/*