[PATCH v2 01/18] mingw: don't call `GetFileAttributes()` twice in `mingw_lstat()`
- From
Karsten Blees via GitGitGadget <gitgitgadget@gmail.com>
- Date
- Jan 9, 2026, 20:04 UTC
- Message-ID
- <6ec4ff74577f3690a11160812666e5ca800d9d65.1767989115.git.gitgitgadget@gmail.com>
- In-Reply-To
- <pull.2018.v2.git.1767989115.gitgitgadget@gmail.com>
From: Karsten Blees <karsten.blees@gmail.com>
The Win32 API function `GetFileAttributes()` cannot handle paths with trailing dir separators. The current `mingw_stat()`/`mingw_lstat()` implementation calls `GetFileAttributes()` twice if the path has trailing slashes (first with the original path that was passed as function parameter, and and a second time with a path copy with trailing '/' removed).
With the conversion to wide Unicode, we get the length of the path for free, and also have a (wide char) buffer that can be modified. This makes it easy to avoid that extraneous Win32 API call.
Signed-off-by: Karsten Blees <karsten.blees@gmail.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> --- compat/mingw.c | 53 ++++++++++++++------------------------------------ 1 file changed, 15 insertions(+), 38 deletions(-)
diff --git a/compat/mingw.c b/compat/mingw.c index cf4f3c92e7..ae6826948e 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -918,8 +918,9 @@ static int has_valid_directory_prefix(wchar_t *wfilename) } /* We keep the do_lstat code in a separate function to avoid recursion. - * When a path ends with a slash, the stat will fail with ENOENT. In - * this case, we strip the trailing slashes and stat again. + * When a path ends with a slash, the call to `GetFileAttributedExW()` + * would fail. To prevent this, we strip any trailing slashes before that + * call. * * If follow is true then act like stat() and report on the link * target. Otherwise report on the link itself. @@ -928,9 +929,18 @@ static int do_lstat(int follow, const char *file_name, struct stat *buf) { WIN32_FILE_ATTRIBUTE_DATA fdata; wchar_t wfilename[MAX_PATH]; - if (xutftowcs_path(wfilename, file_name) < 0) + int wlen = xutftowcs_path(wfilename, file_name); + if (wlen < 0) return -1; + /* strip trailing '/', or GetFileAttributes will fail */ + while (wlen && is_dir_sep(wfilename[wlen - 1])) + wfilename[--wlen] = 0; + if (!wlen) { + errno = ENOENT; + return -1; + } + if (GetFileAttributesExW(wfilename, GetFileExInfoStandard, &fdata)) { buf->st_ino = 0; buf->st_gid = 0; @@ -990,39 +1000,6 @@ static int do_lstat(int follow, const char *file_name, struct stat *buf) return -1; } -/* We provide our own lstat/fstat functions, since the provided - * lstat/fstat functions are so slow. These stat functions are - * tailored for Git's usage (read: fast), and are not meant to be - * complete. Note that Git stat()s are redirected to mingw_lstat() - * too, since Windows doesn't really handle symlinks that well. - */ -static int do_stat_internal(int follow, const char *file_name, struct stat *buf) -{ - size_t namelen; - char alt_name[PATH_MAX]; - - if (!do_lstat(follow, file_name, buf)) - return 0; - - /* if file_name ended in a '/', Windows returned ENOENT; - * try again without trailing slashes - */ - if (errno != ENOENT) - return -1; - - namelen = strlen(file_name); - if (namelen && file_name[namelen-1] != '/') - return -1; - while (namelen && file_name[namelen-1] == '/') - --namelen; - if (!namelen || namelen >= PATH_MAX) - return -1; - - memcpy(alt_name, file_name, namelen); - alt_name[namelen] = 0; - return do_lstat(follow, alt_name, buf); -} - static int get_file_info_by_handle(HANDLE hnd, struct stat *buf) { BY_HANDLE_FILE_INFORMATION fdata; @@ -1048,11 +1025,11 @@ static int get_file_info_by_handle(HANDLE hnd, struct stat *buf) int mingw_lstat(const char *file_name, struct stat *buf) { - return do_stat_internal(0, file_name, buf); + return do_lstat(0, file_name, buf); } int mingw_stat(const char *file_name, struct stat *buf) { - return do_stat_internal(1, file_name, buf); + return do_lstat(1, file_name, buf); } int mingw_fstat(int fd, struct stat *buf)
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