mercurial/compat.h

transaction: avoid file stat ambiguity only for files in blacklist

Advancing mtime by os.utime() fails for EPERM, if the target file is
owned by another. bff5ccbe5ead and related changes made some code
paths give advancing mtime up in such case, to fix issue5418.

This causes file stat ambiguity (again), if it is owned by another.

    https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan

To avoid file stat ambiguity in such case, especially for
.hg/dirstate, ed66ec39933f made vfs.rename() copy the target file, and
advance mtime of renamed one again, if EPERM (see issue5584 for detail).

But straightforward "copy if EPERM" isn't reasonable for truncation of
append-only files at rollbacking, because rollbacking might cost much
for truncation of many filelogs, even though filelogs aren't
filecache-ed.

Therefore, this patch introduces blacklist "checkambigfiles", and
avoids file stat ambiguity only for files specified in this blacklist.

This patch consists of two parts below, which should be applied at
once in order to avoid regression.

  - specify 'checkambig=True' at vfs.open(mode='a') in _playback()
    according to checkambigfiles

  - invoke _playback() with checkambigfiles
    - add transaction.__init__() checkambigfiles argument, for _abort()
      - make localrepo instantiate transaction with _cachedfiles
    - add rollback() checkambigfiles argument, for "hg rollback/recover"
      - make localrepo invoke rollback() with _cachedfiles

After this patch, straightforward "copy if EPERM" will be reasonable
at closing the file opened with checkambig=True, because this policy
is applied only on files, which are listed in blacklist
"checkambigfiles".

#ifndef _HG_COMPAT_H_
#define _HG_COMPAT_H_

#ifdef _WIN32
#ifdef _MSC_VER
/* msvc 6.0 has problems */
#define inline __inline
#if defined(_WIN64)
typedef __int64 ssize_t;
#else
typedef int ssize_t;
#endif
typedef signed char int8_t;
typedef short int16_t;
typedef long int32_t;
typedef __int64 int64_t;
typedef unsigned char uint8_t;
typedef unsigned short uint16_t;
typedef unsigned long uint32_t;
typedef unsigned __int64 uint64_t;
#else
#include <stdint.h>
#endif
#else
/* not windows */
#include <sys/types.h>
#if defined __BEOS__ && !defined __HAIKU__
#include <ByteOrder.h>
#else
#include <arpa/inet.h>
#endif
#include <inttypes.h>
#endif

#if defined __hpux || defined __SUNPRO_C || defined _AIX
#define inline
#endif

#ifdef __linux
#define inline __inline
#endif

#endif