0003-WIP-Use-some-generic-selection.patch

From b8f2c2f144c1763029ba8b84093a1885f57627a1 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Fri, 27 Dec 2024 11:07:35 +0100
Subject: [PATCH 3/3] WIP: Use some generic selection

Use generic selection (C11 _Generic) to allow a few functions in
htup_details.h to work with both HeapTuple and MinimalTuple.
---
 src/include/access/htup_details.h | 50 +++++++++++++++++++++++--------
 1 file changed, 37 insertions(+), 13 deletions(-)

diff --git a/src/include/access/htup_details.h b/src/include/access/htup_details.h
index bab480fe2f0..cb862ff089d 100644
--- a/src/include/access/htup_details.h
+++ b/src/include/access/htup_details.h
@@ -574,21 +574,23 @@ HeapTupleHeaderClearHeapOnly(HeapTupleHeaderData *tup)
 	tup->t_infomask2 &= ~HEAP_ONLY_TUPLE;
 }
 
-/*
- * These are used with both HeapTuple and MinimalTuple, so they must be
- * macros.
- */
-
-#define HeapTupleHeaderGetNatts(tup) \
-	((tup)->t_infomask2 & HEAP_NATTS_MASK)
+static inline int
+HeapTupleHeaderGetNatts(const HeapTupleHeaderData *tup)
+{
+	return tup->t_infomask2 & HEAP_NATTS_MASK;
+}
 
-#define HeapTupleHeaderSetNatts(tup, natts) \
-( \
-	(tup)->t_infomask2 = ((tup)->t_infomask2 & ~HEAP_NATTS_MASK) | (natts) \
-)
+static inline void
+HeapTupleHeaderSetNatts(HeapTupleHeaderData *tup, int natts)
+{
+	tup->t_infomask2 = (tup->t_infomask2 & ~HEAP_NATTS_MASK) | natts;
+}
 
-#define HeapTupleHeaderHasExternal(tup) \
-		(((tup)->t_infomask & HEAP_HASEXTERNAL) != 0)
+static inline bool
+HeapTupleHeaderHasExternal(HeapTupleHeaderData *tup)
+{
+	return (tup->t_infomask & HEAP_HASEXTERNAL) != 0;
+}
 
 
 /*
@@ -725,6 +727,28 @@ HeapTupleHeaderClearMatch(MinimalTupleData *tup)
 	tup->t_infomask2 &= ~HEAP_TUPLE_HAS_MATCH;
 }
 
+/*
+ * Accessor functions for both HeapTupleHeader and MinimalTuple
+ */
+
+static inline bool
+MinimalTupleHasExternal(MinimalTupleData *tup)
+{
+	return (tup->t_infomask & HEAP_HASEXTERNAL) != 0;
+}
+
+#define HeapTupleHeaderHasExternal(tup) \
+	_Generic((tup), HeapTupleHeaderData*: HeapTupleHeaderHasExternal, MinimalTupleData*: MinimalTupleHasExternal)(tup)
+
+static inline void
+MinimalTupleSetNatts(MinimalTupleData *tup, int natts)
+{
+	tup->t_infomask2 = (tup->t_infomask2 & ~HEAP_NATTS_MASK) | natts;
+}
+
+#define HeapTupleHeaderSetNatts(tup, natts) \
+	_Generic((tup), HeapTupleHeaderData*: HeapTupleHeaderSetNatts, MinimalTupleData*: MinimalTupleSetNatts)(tup, natts)
+
 
 /*
  * GETSTRUCT - given a HeapTuple pointer, return address of the user data
-- 
2.47.1