Implement SQL-spec RETURNS TABLE syntax for functions.

(Unlike the original submission, this patch treats TABLE output parameters
as being entirely equivalent to OUT parameters -- tgl)

Pavel Stehule

1 files changed, 144 insertions, 1 deletions

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index c7f896c524a..b3603c53c16 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.277 2008/07/16 16:55:23 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.278 2008/07/18 03:32:52 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -135,6 +135,8 @@ static char *pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
 							int prettyFlags);
 static char *pg_get_expr_worker(text *expr, Oid relid, char *relname,
 				   int prettyFlags);
+static int print_function_arguments(StringInfo buf, HeapTuple proctup,
+						 bool print_table_args);
 static void make_ruledef(StringInfo buf, HeapTuple ruletup, TupleDesc rulettc,
 			 int prettyFlags);
 static void make_viewdef(StringInfo buf, HeapTuple ruletup, TupleDesc rulettc,
@@ -1396,6 +1398,147 @@ pg_get_serial_sequence(PG_FUNCTION_ARGS)
 
 
 /*
+ * pg_get_function_arguments
+ *		Get a nicely-formatted list of arguments for a function.
+ *		This is everything that would go between the parentheses in
+ *		CREATE FUNCTION.
+ */
+Datum
+pg_get_function_arguments(PG_FUNCTION_ARGS)
+{
+	Oid			funcid = PG_GETARG_OID(0);
+	StringInfoData buf;
+	HeapTuple	proctup;
+
+	initStringInfo(&buf);
+
+	proctup = SearchSysCache(PROCOID,
+							 ObjectIdGetDatum(funcid),
+							 0, 0, 0);
+	if (!HeapTupleIsValid(proctup))
+		elog(ERROR, "cache lookup failed for function %u", funcid);
+
+	(void) print_function_arguments(&buf, proctup, false);
+
+	ReleaseSysCache(proctup);
+
+	PG_RETURN_TEXT_P(string_to_text(buf.data));
+}
+
+/*
+ * pg_get_function_result
+ *		Get a nicely-formatted version of the result type of a function.
+ *		This is what would appear after RETURNS in CREATE FUNCTION.
+ */
+Datum
+pg_get_function_result(PG_FUNCTION_ARGS)
+{
+	Oid			funcid = PG_GETARG_OID(0);
+	StringInfoData buf;
+	HeapTuple	proctup;
+	Form_pg_proc procform;
+	int			ntabargs = 0;
+
+	initStringInfo(&buf);
+
+	proctup = SearchSysCache(PROCOID,
+							 ObjectIdGetDatum(funcid),
+							 0, 0, 0);
+	if (!HeapTupleIsValid(proctup))
+		elog(ERROR, "cache lookup failed for function %u", funcid);
+	procform = (Form_pg_proc) GETSTRUCT(proctup);
+
+	if (procform->proretset)
+	{
+		/* It might be a table function; try to print the arguments */
+		appendStringInfoString(&buf, "TABLE(");
+		ntabargs = print_function_arguments(&buf, proctup, true);
+		if (ntabargs > 0)
+			appendStringInfoString(&buf, ")");
+		else
+			resetStringInfo(&buf);
+	}
+
+	if (ntabargs == 0)
+	{
+		/* Not a table function, so do the normal thing */
+		if (procform->proretset)
+			appendStringInfoString(&buf, "SETOF ");
+		appendStringInfoString(&buf, format_type_be(procform->prorettype));
+	}
+
+	ReleaseSysCache(proctup);
+
+	PG_RETURN_TEXT_P(string_to_text(buf.data));
+}
+
+/*
+ * Common code for pg_get_function_arguments and pg_get_function_result:
+ * append the desired subset of arguments to buf.  We print only TABLE
+ * arguments when print_table_args is true, and all the others when it's false.
+ * Function return value is the number of arguments printed.
+ */
+static int
+print_function_arguments(StringInfo buf, HeapTuple proctup,
+						 bool print_table_args)
+{
+	int			numargs;
+	Oid		   *argtypes;
+	char	  **argnames;
+	char	   *argmodes;
+	int			argsprinted;
+	int			i;
+
+	numargs = get_func_arg_info(proctup,
+								&argtypes, &argnames, &argmodes);
+
+	argsprinted = 0;
+	for (i = 0; i < numargs; i++)
+	{
+		Oid		argtype = argtypes[i];
+		char   *argname = argnames ? argnames[i] : NULL;
+		char	argmode = argmodes ? argmodes[i] : PROARGMODE_IN;
+		const char *modename;
+
+		if (print_table_args != (argmode == PROARGMODE_TABLE))
+			continue;
+
+		switch (argmode)
+		{
+			case PROARGMODE_IN:
+				modename = "";
+				break;
+			case PROARGMODE_INOUT:
+				modename = "INOUT ";
+				break;
+			case PROARGMODE_OUT:
+				modename = "OUT ";
+				break;
+			case PROARGMODE_VARIADIC:
+				modename = "VARIADIC ";
+				break;
+			case PROARGMODE_TABLE:
+				modename = "";
+				break;
+			default:
+				elog(ERROR, "invalid parameter mode '%c'", argmode);
+				modename = NULL; /* keep compiler quiet */
+				break;
+		}
+		if (argsprinted)
+			appendStringInfoString(buf, ", ");
+		appendStringInfoString(buf, modename);
+		if (argname && argname[0])
+			appendStringInfo(buf, "%s ", argname);
+		appendStringInfoString(buf, format_type_be(argtype));
+		argsprinted++;
+	}
+
+	return argsprinted;
+}
+
+
+/*
  * deparse_expression			- General utility for deparsing expressions
  *
  * calls deparse_expression_pretty with all prettyPrinting disabled