From e38b1eb0986990d539e056a65c6b122b295ce932 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 20 Feb 2015 16:51:53 -0500
Subject: [PATCH] Use FLEXIBLE_ARRAY_MEMBER in struct varlena.
This forces some minor coding adjustments in tuptoaster.c and inv_api.c,
but the new coding there is cleaner anyway.
Michael Paquier
---
src/backend/access/heap/tuptoaster.c | 8 +++++---
src/backend/storage/large_object/inv_api.c | 16 ++++++++++------
src/include/c.h | 2 +-
3 files changed, 16 insertions(+), 10 deletions(-)
diff --git a/src/backend/access/heap/tuptoaster.c b/src/backend/access/heap/tuptoaster.c
index f8c1401d7fa..deb33720ab7 100644
--- a/src/backend/access/heap/tuptoaster.c
+++ b/src/backend/access/heap/tuptoaster.c
@@ -1365,11 +1365,13 @@ toast_save_datum(Relation rel, Datum value,
CommandId mycid = GetCurrentCommandId(true);
struct varlena *result;
struct varatt_external toast_pointer;
- struct
+ union
{
struct varlena hdr;
- char data[TOAST_MAX_CHUNK_SIZE]; /* make struct big enough */
- int32 align_it; /* ensure struct is aligned well enough */
+ /* this is to make the union big enough for a chunk: */
+ char data[TOAST_MAX_CHUNK_SIZE + VARHDRSZ];
+ /* ensure union is aligned well enough: */
+ int32 align_it;
} chunk_data;
int32 chunk_size;
int32 chunk_seq = 0;
diff --git a/src/backend/storage/large_object/inv_api.c b/src/backend/storage/large_object/inv_api.c
index a19c40186f5..ecd5e618f3c 100644
--- a/src/backend/storage/large_object/inv_api.c
+++ b/src/backend/storage/large_object/inv_api.c
@@ -562,11 +562,13 @@ inv_write(LargeObjectDesc *obj_desc, const char *buf, int nbytes)
bool neednextpage;
bytea *datafield;
bool pfreeit;
- struct
+ union
{
bytea hdr;
- char data[LOBLKSIZE]; /* make struct big enough */
- int32 align_it; /* ensure struct is aligned well enough */
+ /* this is to make the union big enough for a LO data chunk: */
+ char data[LOBLKSIZE + VARHDRSZ];
+ /* ensure union is aligned well enough: */
+ int32 align_it;
} workbuf;
char *workb = VARDATA(&workbuf.hdr);
HeapTuple newtup;
@@ -748,11 +750,13 @@ inv_truncate(LargeObjectDesc *obj_desc, int64 len)
SysScanDesc sd;
HeapTuple oldtuple;
Form_pg_largeobject olddata;
- struct
+ union
{
bytea hdr;
- char data[LOBLKSIZE]; /* make struct big enough */
- int32 align_it; /* ensure struct is aligned well enough */
+ /* this is to make the union big enough for a LO data chunk: */
+ char data[LOBLKSIZE + VARHDRSZ];
+ /* ensure union is aligned well enough: */
+ int32 align_it;
} workbuf;
char *workb = VARDATA(&workbuf.hdr);
HeapTuple newtup;
diff --git a/src/include/c.h b/src/include/c.h
index 2de86f91416..ee615ee687f 100644
--- a/src/include/c.h
+++ b/src/include/c.h
@@ -391,7 +391,7 @@ typedef struct
struct varlena
{
char vl_len_[4]; /* Do not touch this field directly! */
- char vl_dat[1];
+ char vl_dat[FLEXIBLE_ARRAY_MEMBER]; /* Data content is here */
};
#define VARHDRSZ ((int32) sizeof(int32))
--
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