This adds a Windows implementation of pread. Note that it is NOT safe to intersperse calls to read() and pread() on a file descriptor. According to the ReadFile spec, using the 'overlapped' argument should not affect the implicit position pointer of the descriptor. Experiments have shown that this is, in fact, a lie.
To accomodate that fact, this change also incorporates: http://article.gmane.org/gmane.comp.version-control.git/196042 ... which gives each index-pack thread its own file descriptor. Signed-off-by: Stefan Zager <sza...@chromium.org> --- builtin/index-pack.c | 30 ++++++++++++++++++++---------- compat/mingw.c | 37 ++++++++++++++++++++++++++++++++++++- compat/mingw.h | 3 +++ config.mak.uname | 1 - 4 files changed, 59 insertions(+), 12 deletions(-) diff --git a/builtin/index-pack.c b/builtin/index-pack.c index 2f37a38..63b8b0e 100644 --- a/builtin/index-pack.c +++ b/builtin/index-pack.c @@ -40,17 +40,17 @@ struct base_data { int ofs_first, ofs_last; }; -#if !defined(NO_PTHREADS) && defined(NO_THREAD_SAFE_PREAD) -/* pread() emulation is not thread-safe. Disable threading. */ -#define NO_PTHREADS -#endif - struct thread_local { #ifndef NO_PTHREADS pthread_t thread; #endif struct base_data *base_cache; size_t base_cache_used; + /* + * To accomodate platforms that have pthreads, but don't have a + * thread-safe pread, give each thread its own file descriptor. + */ + int pack_fd; }; /* @@ -91,7 +91,8 @@ static off_t consumed_bytes; static unsigned deepest_delta; static git_SHA_CTX input_ctx; static uint32_t input_crc32; -static int input_fd, output_fd, pack_fd; +static const char *curr_pack; +static int input_fd, output_fd; #ifndef NO_PTHREADS @@ -134,6 +135,7 @@ static inline void unlock_mutex(pthread_mutex_t *mutex) */ static void init_thread(void) { + int i; init_recursive_mutex(&read_mutex); pthread_mutex_init(&counter_mutex, NULL); pthread_mutex_init(&work_mutex, NULL); @@ -141,11 +143,17 @@ static void init_thread(void) pthread_mutex_init(&deepest_delta_mutex, NULL); pthread_key_create(&key, NULL); thread_data = xcalloc(nr_threads, sizeof(*thread_data)); + for (i = 0; i < nr_threads; i++) { + thread_data[i].pack_fd = open(curr_pack, O_RDONLY); + if (thread_data[i].pack_fd == -1) + die_errno("unable to open %s", curr_pack); + } threads_active = 1; } static void cleanup_thread(void) { + int i; if (!threads_active) return; threads_active = 0; @@ -155,6 +163,8 @@ static void cleanup_thread(void) if (show_stat) pthread_mutex_destroy(&deepest_delta_mutex); pthread_key_delete(key); + for (i = 0; i < nr_threads; i++) + close(thread_data[i].pack_fd); free(thread_data); } @@ -288,13 +298,13 @@ static const char *open_pack_file(const char *pack_name) output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600); if (output_fd < 0) die_errno(_("unable to create '%s'"), pack_name); - pack_fd = output_fd; + nothread_data.pack_fd = output_fd; } else { input_fd = open(pack_name, O_RDONLY); if (input_fd < 0) die_errno(_("cannot open packfile '%s'"), pack_name); output_fd = -1; - pack_fd = input_fd; + nothread_data.pack_fd = input_fd; } git_SHA1_Init(&input_ctx); return pack_name; @@ -542,7 +552,7 @@ static void *unpack_data(struct object_entry *obj, do { ssize_t n = (len < 64*1024) ? len : 64*1024; - n = pread(pack_fd, inbuf, n, from); + n = pread(get_thread_data()->pack_fd, inbuf, n, from); if (n < 0) die_errno(_("cannot pread pack file")); if (!n) @@ -1490,7 +1500,7 @@ static void show_pack_info(int stat_only) int cmd_index_pack(int argc, const char **argv, const char *prefix) { int i, fix_thin_pack = 0, verify = 0, stat_only = 0; - const char *curr_pack, *curr_index; + const char *curr_index; const char *index_name = NULL, *pack_name = NULL; const char *keep_name = NULL, *keep_msg = NULL; char *index_name_buf = NULL, *keep_name_buf = NULL; diff --git a/compat/mingw.c b/compat/mingw.c index 383cafe..0efc570 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -329,7 +329,42 @@ int mingw_mkdir(const char *path, int mode) return ret; } -int mingw_open (const char *filename, int oflags, ...) + +/* + * Warning: contrary to the specificiation, when ReadFile() is called + * with an 'overlapped' argument, it *will* modify the implict position + * pointer for the file descriptor. As a result, it is *not* safe to + * intersperse calls to read() and pread() on a single file descriptor. + */ +ssize_t mingw_pread(int fd, void *buf, size_t count, off64_t offset) +{ + HANDLE hand = (HANDLE)_get_osfhandle(fd); + if (hand == INVALID_HANDLE_VALUE) { + errno = EBADF; + return -1; + } + + LARGE_INTEGER offset_value; + offset_value.QuadPart = offset; + + DWORD bytes_read = 0; + OVERLAPPED overlapped = {0}; + overlapped.Offset = offset_value.LowPart; + overlapped.OffsetHigh = offset_value.HighPart; + BOOL result = ReadFile(hand, buf, count, &bytes_read, &overlapped); + + ssize_t ret = bytes_read; + + if (!result && GetLastError() != ERROR_HANDLE_EOF) + { + errno = err_win_to_posix(GetLastError()); + ret = -1; + } + + return ret; +} + +int mingw_open(const char *filename, int oflags, ...) { va_list args; unsigned mode; diff --git a/compat/mingw.h b/compat/mingw.h index 08b83fe..377ba50 100644 --- a/compat/mingw.h +++ b/compat/mingw.h @@ -174,6 +174,9 @@ int mingw_unlink(const char *pathname); int mingw_rmdir(const char *path); #define rmdir mingw_rmdir +ssize_t mingw_pread(int fd, void *buf, size_t count, off64_t offset); +#define pread mingw_pread + int mingw_open (const char *filename, int oflags, ...); #define open mingw_open diff --git a/config.mak.uname b/config.mak.uname index e8acc39..b405524 100644 --- a/config.mak.uname +++ b/config.mak.uname @@ -474,7 +474,6 @@ ifeq ($(uname_S),NONSTOP_KERNEL) endif ifneq (,$(findstring MINGW,$(uname_S))) pathsep = ; - NO_PREAD = YesPlease NEEDS_CRYPTO_WITH_SSL = YesPlease NO_LIBGEN_H = YesPlease NO_POLL = YesPlease -- 1.9.0.279.gdc9e3eb -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
