From 8f0339263dd21bb04c1b96a0e850a9b57a2e3f8b Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathan@postgresql.org>
Date: Thu, 20 Jul 2023 09:45:03 -0700
Subject: [PATCH v2 2/4] make binaryheap available to frontend

---
 src/backend/lib/Makefile                 |  1 -
 src/backend/lib/meson.build              |  1 -
 src/common/Makefile                      |  1 +
 src/{backend/lib => common}/binaryheap.c | 15 ++++++++++++
 src/common/meson.build                   |  1 +
 src/include/lib/binaryheap.h             | 29 ++++++++++++++++++++++++
 6 files changed, 46 insertions(+), 2 deletions(-)
 rename src/{backend/lib => common}/binaryheap.c (96%)

diff --git a/src/backend/lib/Makefile b/src/backend/lib/Makefile
index 9dad31398a..b6cefd9cca 100644
--- a/src/backend/lib/Makefile
+++ b/src/backend/lib/Makefile
@@ -13,7 +13,6 @@ top_builddir = ../../..
 include $(top_builddir)/src/Makefile.global
 
 OBJS = \
-	binaryheap.o \
 	bipartite_match.o \
 	bloomfilter.o \
 	dshash.o \
diff --git a/src/backend/lib/meson.build b/src/backend/lib/meson.build
index 974cab8776..b4e88f54ae 100644
--- a/src/backend/lib/meson.build
+++ b/src/backend/lib/meson.build
@@ -1,7 +1,6 @@
 # Copyright (c) 2022-2023, PostgreSQL Global Development Group
 
 backend_sources += files(
-  'binaryheap.c',
   'bipartite_match.c',
   'bloomfilter.c',
   'dshash.c',
diff --git a/src/common/Makefile b/src/common/Makefile
index 113029bf7b..cc5c54dcee 100644
--- a/src/common/Makefile
+++ b/src/common/Makefile
@@ -48,6 +48,7 @@ LIBS += $(PTHREAD_LIBS)
 OBJS_COMMON = \
 	archive.o \
 	base64.o \
+	binaryheap.o \
 	checksum_helper.o \
 	compression.o \
 	config_info.o \
diff --git a/src/backend/lib/binaryheap.c b/src/common/binaryheap.c
similarity index 96%
rename from src/backend/lib/binaryheap.c
rename to src/common/binaryheap.c
index 1737546757..7a590eec4a 100644
--- a/src/backend/lib/binaryheap.c
+++ b/src/common/binaryheap.c
@@ -11,10 +11,17 @@
  *-------------------------------------------------------------------------
  */
 
+#ifndef FRONTEND
 #include "postgres.h"
+#else
+#include "postgres_fe.h"
+#endif
 
 #include <math.h>
 
+#ifdef FRONTEND
+#include "common/logging.h"
+#endif
 #include "lib/binaryheap.h"
 
 static void sift_down(binaryheap *heap, int node_off);
@@ -109,7 +116,11 @@ void
 binaryheap_add_unordered(binaryheap *heap, Datum d)
 {
 	if (heap->bh_size >= heap->bh_space)
+#ifdef FRONTEND
+		pg_fatal("out of binary heap slots");
+#else
 		elog(ERROR, "out of binary heap slots");
+#endif
 	heap->bh_has_heap_property = false;
 	heap->bh_nodes[heap->bh_size] = d;
 	heap->bh_size++;
@@ -141,7 +152,11 @@ void
 binaryheap_add(binaryheap *heap, Datum d)
 {
 	if (heap->bh_size >= heap->bh_space)
+#ifdef FRONTEND
+		pg_fatal("out of binary heap slots");
+#else
 		elog(ERROR, "out of binary heap slots");
+#endif
 	heap->bh_nodes[heap->bh_size] = d;
 	heap->bh_size++;
 	sift_up(heap, heap->bh_size - 1);
diff --git a/src/common/meson.build b/src/common/meson.build
index 53942a9a61..3b97497d1a 100644
--- a/src/common/meson.build
+++ b/src/common/meson.build
@@ -3,6 +3,7 @@
 common_sources = files(
   'archive.c',
   'base64.c',
+  'binaryheap.c',
   'checksum_helper.c',
   'compression.c',
   'controldata_utils.c',
diff --git a/src/include/lib/binaryheap.h b/src/include/lib/binaryheap.h
index 52f7b06b25..06e3878cf7 100644
--- a/src/include/lib/binaryheap.h
+++ b/src/include/lib/binaryheap.h
@@ -11,6 +11,35 @@
 #ifndef BINARYHEAP_H
 #define BINARYHEAP_H
 
+/*
+ * XXX: This is obviously a hack.
+ */
+#ifdef FRONTEND
+
+typedef uintptr_t Datum;
+
+/*
+ * DatumGetPointer
+ *		Returns pointer value of a datum.
+ */
+static inline Pointer
+DatumGetPointer(Datum X)
+{
+	return (Pointer) X;
+}
+
+/*
+ * PointerGetDatum
+ *		Returns datum representation for a pointer.
+ */
+static inline Datum
+PointerGetDatum(const void *X)
+{
+	return (Datum) X;
+}
+
+#endif
+
 /*
  * For a max-heap, the comparator must return <0 iff a < b, 0 iff a == b,
  * and >0 iff a > b.  For a min-heap, the conditions are reversed.
-- 
2.25.1