Improvements to status performance on Windows.

Changed win32/path_w32.c to utilize NTFS' FindFirst..FindNext data instead of doing an lstat per file. Avoiding unnecessary directory opens and file scans reduces IO, improving overall performance. Effect is magnified due to NTFS being a kernel mode file system (as opposed to user mode).

src/iterator.c

@@ -984,6 +984,21 @@ static void fs_iterator__seek_frame_start(
 		ff->index = 0;
 }
 
+GIT_INLINE(int) path_dirload_with_stat(
+	const char *path,
+	size_t prefix_len,
+	unsigned int flags,
+	const char *start_stat,
+	const char *end_stat,
+	git_vector *contents)
+{
+#if defined(GIT_WIN32) && !defined(__MINGW32__)
+	return	git_win32_path_dirload_with_stat(path, prefix_len, flags, start_stat, end_stat, contents);
+#else
+	return	git_path_dirload_with_stat(path, prefix_len, flags, start_stat, end_stat, contents);
+#endif
+}
+
 static int fs_iterator__expand_dir(fs_iterator *fi)
 {
 	int error;
@@ -998,7 +1013,7 @@ static int fs_iterator__expand_dir(fs_iterator *fi)
 	ff = fs_iterator__alloc_frame(fi);
 	GITERR_CHECK_ALLOC(ff);
 
-	error = git_path_dirload_with_stat(
+	error = path_dirload_with_stat(
 		fi->path.ptr, fi->root_len, fi->dirload_flags,
 		fi->base.start, fi->base.end, &ff->entries);
 
@@ -1350,6 +1365,7 @@ GIT_INLINE(git_dir_flag) git_entry__dir_flag(git_index_entry *entry) {
 		? S_ISDIR(entry->mode) ? GIT_DIR_FLAG_TRUE : GIT_DIR_FLAG_FALSE
 		: GIT_DIR_FLAG_UNKNOWN;
 #else
+	GIT_UNUSED(entry);
 	return GIT_DIR_FLAG_UNKNOWN;
 #endif
 }

src/win32/path_w32.c

@@ -9,6 +9,9 @@
 #include "path.h"
 #include "path_w32.h"
 #include "utf-conv.h"
+#include "posix.h"
+#include "reparse.h"
+#include "dir.h"
 
 #define PATH__NT_NAMESPACE     L"\\\\?\\"
 #define PATH__NT_NAMESPACE_LEN 4
@@ -27,6 +30,8 @@
 #define path__is_unc(p) \
 	(((p)[0] == '\\' && (p)[1] == '\\') || ((p)[0] == '/' && (p)[1] == '/'))
 
+#define PATH__MAX_UNC_LEN (32767)
+
 GIT_INLINE(int) path__cwd(wchar_t *path, int size)
 {
 	int len;
@@ -303,3 +308,223 @@ char *git_win32_path_8dot3_name(const char *path)
 
 	return shortname;
 }
+
+#if !defined(__MINGW32__)
+int git_win32_path_dirload_with_stat(
+	const char *path,
+	size_t prefix_len,
+	unsigned int flags,
+	const char *start_stat,
+	const char *end_stat,
+	git_vector *contents)
+{
+	int error = 0;
+	git_path_with_stat *ps;
+	git_win32_path pathw;
+	DIR *dir;
+	int(*strncomp)(const char *a, const char *b, size_t sz);
+	size_t cmp_len;
+	size_t start_len = start_stat ? strlen(start_stat) : 0;
+	size_t end_len = end_stat ? strlen(end_stat) : 0;
+	size_t path_size = strlen(path);
+	const char *repo_path = path + prefix_len;
+	size_t repo_path_len = strlen(repo_path);
+	char work_path[PATH__MAX_UNC_LEN];
+	git_win32_path target;
+	size_t path_len;
+	int fMode;
+
+	if (!git_win32__findfirstfile_filter(pathw, path)) {
+		error = -1;
+		giterr_set(GITERR_OS, "Could not parse the path '%s'", path);
+		goto clean_up_and_exit;
+	}
+
+	strncomp = (flags & GIT_PATH_DIR_IGNORE_CASE) != 0 
+		       ? git__strncasecmp 
+		       : git__strncmp;
+
+	/* use of FIND_FIRST_EX_LARGE_FETCH flag in the FindFirstFileExW call could benefit perormance
+	 * here when querying large repositories on Windows 7 (0x0600) or newer versions of Windows.
+	 * doing so could introduce compatibility issues on older versions of Windows. */
+	dir = git__calloc(1, sizeof(DIR));
+	dir->h = FindFirstFileExW(pathw, FindExInfoBasic, &dir->f, FindExSearchNameMatch, NULL, 0);
+	dir->first = 1;
+	if (dir->h == INVALID_HANDLE_VALUE) {
+		error = -1;
+		giterr_set(GITERR_OS, "Could not open directory '%s'", path);
+		goto clean_up_and_exit;
+	}
+	
+	if (repo_path_len > PATH__MAX_UNC_LEN) {
+		error = -1;
+		giterr_set(GITERR_OS, "Could not open directory '%s'", path);
+		goto clean_up_and_exit;
+	}
+
+	memcpy(work_path, repo_path, repo_path_len);
+
+	while (dir) {
+		if (!git_path_is_dot_or_dotdotW(dir->f.cFileName)) {
+			path_len = git__utf16_to_8(work_path + repo_path_len, ARRAYSIZE(work_path) - repo_path_len, dir->f.cFileName);
+
+			work_path[path_len + repo_path_len] = '\0';
+			path_len = path_len + repo_path_len;
+
+			cmp_len = min(start_len, path_len);
+			if (!(cmp_len && strncomp(work_path, start_stat, cmp_len) < 0)) {
+				cmp_len = min(end_len, path_len);
+				if (!(cmp_len && strncomp(work_path, end_stat, cmp_len) > 0)) {
+					fMode = S_IREAD;
+
+					if (dir->f.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
+						fMode |= S_IFDIR;
+					else
+						fMode |= S_IFREG;
+
+					if (!(dir->f.dwFileAttributes & FILE_ATTRIBUTE_READONLY))
+						fMode |= S_IWRITE;
+
+					ps = git__calloc(1, sizeof(git_path_with_stat) + path_len + 2);
+					memcpy(ps->path, work_path, path_len + 1);
+					ps->path_len = path_len;
+					ps->st.st_atime = filetime_to_time_t(&dir->f.ftLastAccessTime);
+					ps->st.st_ctime = filetime_to_time_t(&dir->f.ftCreationTime);
+					ps->st.st_mtime = filetime_to_time_t(&dir->f.ftLastWriteTime);
+					ps->st.st_size = dir->f.nFileSizeHigh;
+					ps->st.st_size <<= 32;
+					ps->st.st_size |= dir->f.nFileSizeLow;
+					ps->st.st_dev = ps->st.st_rdev = (_getdrive() - 1);
+					ps->st.st_mode = (mode_t)fMode;
+					ps->st.st_ino = 0;
+					ps->st.st_gid = 0;
+					ps->st.st_uid = 0;
+					ps->st.st_nlink = 1;
+
+					if (dir->f.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) {
+						if (git_win32_path_readlink_w(target, dir->f.cFileName) >= 0) {
+							ps->st.st_mode = (ps->st.st_mode & ~S_IFMT) | S_IFLNK;
+
+							/* st_size gets the UTF-8 length of the target name, in bytes,
+							 * not counting the NULL terminator */
+							if ((ps->st.st_size = git__utf16_to_8(NULL, 0, target)) < 0) {
+								error = -1;
+								giterr_set(GITERR_OS, "Could not manage reparse link '%s'", dir->f.cFileName);
+								goto clean_up_and_exit;
+							}
+						}
+					}
+
+					if (S_ISDIR(ps->st.st_mode)) {
+						ps->path[ps->path_len++] = '/';
+						ps->path[ps->path_len] = '\0';
+					} else if (!S_ISREG(ps->st.st_mode) && !S_ISLNK(ps->st.st_mode)) {
+						git__free(ps);
+						ps = NULL;
+					}
+
+					if (ps)
+						git_vector_insert(contents, ps);
+				}
+			}
+		}
+
+		memset(&dir->f, 0, sizeof(git_path_with_stat));
+		dir->first = 0;
+
+		if (!FindNextFileW(dir->h, &dir->f)) {
+			if (GetLastError() == ERROR_NO_MORE_FILES)
+				break;
+			else {
+				error = -1;
+				giterr_set(GITERR_OS, "Could not get attributes for file in '%s'", path);
+				goto clean_up_and_exit;
+			}
+		}
+	}
+
+	/* sort now that directory suffix is added */
+	git_vector_sort(contents);
+
+clean_up_and_exit:
+
+	if (dir) {
+		FindClose(dir->h);
+		free(dir);
+	}
+
+	return error;
+}
+#endif
+
+static bool path_is_volume(wchar_t *target, size_t target_len)
+{
+	return (target_len && wcsncmp(target, L"\\??\\Volume{", 11) == 0);
+}
+
+/* On success, returns the length, in characters, of the path stored in dest.
+* On failure, returns a negative value. */
+int git_win32_path_readlink_w(git_win32_path dest, const git_win32_path path)
+{
+	BYTE buf[MAXIMUM_REPARSE_DATA_BUFFER_SIZE];
+	GIT_REPARSE_DATA_BUFFER *reparse_buf = (GIT_REPARSE_DATA_BUFFER *)buf;
+	HANDLE handle = NULL;
+	DWORD ioctl_ret;
+	wchar_t *target;
+	size_t target_len;
+
+	int error = -1;
+
+	handle = CreateFileW(path, GENERIC_READ,
+		FILE_SHARE_READ | FILE_SHARE_DELETE, NULL, OPEN_EXISTING,
+		FILE_FLAG_OPEN_REPARSE_POINT | FILE_FLAG_BACKUP_SEMANTICS, NULL);
+
+	if (handle == INVALID_HANDLE_VALUE) {
+		errno = ENOENT;
+		return -1;
+	}
+
+	if (!DeviceIoControl(handle, FSCTL_GET_REPARSE_POINT, NULL, 0,
+		reparse_buf, sizeof(buf), &ioctl_ret, NULL)) {
+		errno = EINVAL;
+		goto on_error;
+	}
+
+	switch (reparse_buf->ReparseTag) {
+	case IO_REPARSE_TAG_SYMLINK:
+		target = reparse_buf->SymbolicLinkReparseBuffer.PathBuffer +
+			(reparse_buf->SymbolicLinkReparseBuffer.SubstituteNameOffset / sizeof(WCHAR));
+		target_len = reparse_buf->SymbolicLinkReparseBuffer.SubstituteNameLength / sizeof(WCHAR);
+	break;
+	case IO_REPARSE_TAG_MOUNT_POINT:
+		target = reparse_buf->MountPointReparseBuffer.PathBuffer +
+			(reparse_buf->MountPointReparseBuffer.SubstituteNameOffset / sizeof(WCHAR));
+		target_len = reparse_buf->MountPointReparseBuffer.SubstituteNameLength / sizeof(WCHAR);
+	break;
+	default:
+		errno = EINVAL;
+		goto on_error;
+	}
+
+	if (path_is_volume(target, target_len)) {
+		/* This path is a reparse point that represents another volume mounted
+		* at this location, it is not a symbolic link our input was canonical.
+		*/
+		errno = EINVAL;
+		error = -1;
+	} else if (target_len) {
+		/* The path may need to have a prefix removed. */
+		target_len = git_win32__canonicalize_path(target, target_len);
+
+		/* Need one additional character in the target buffer
+		* for the terminating NULL. */
+		if (GIT_WIN_PATH_UTF16 > target_len) {
+			wcscpy(dest, target);
+			error = (int)target_len;
+		}
+	}
+
+on_error:
+	CloseHandle(handle);
+	return error;
+}

src/win32/path_w32.h

@@ -8,6 +8,7 @@
 #define INCLUDE_git_path_w32_h__
 
 #include "common.h"
+#include "vector.h"
 
 /*
  * Provides a large enough buffer to support Windows paths:  MAX_PATH is
@@ -79,4 +80,30 @@ extern int git_win32_path_to_utf8(git_win32_utf8_path dest, const wchar_t *src);
  */
 extern char *git_win32_path_8dot3_name(const char *path);
 
+#if !defined(__MINGW32__)
+/**
+ * Load all directory entries along with stat info into a vector.
+ * Performed in a single pass per directory for optimized performance on Windows.
+ *
+ * This adds four things on top of plain `git_path_dirload`:
+ *
+ * 1. Each entry in the vector is a `git_path_with_stat` struct that
+ *    contains both the path and the stat info
+ * 2. The entries will be sorted alphabetically
+ * 3. Entries that are directories will be suffixed with a '/'
+ * 4. Optionally, you can be a start and end prefix and only elements
+ *    after the start and before the end (inclusively) will be stat'ed.
+ *
+ * @param path The directory to read from
+ * @param prefix_len The trailing part of path to prefix to entry paths
+ * @param flags GIT_PATH_DIR flags from above
+ * @param start_stat As optimization, only stat values after this prefix
+ * @param end_stat As optimization, only stat values before this prefix
+ * @param contents Vector to fill with git_path_with_stat structures
+ */
+extern int git_win32_path_dirload_with_stat(const char *path, size_t prefix_len, unsigned int flags, const char *start_stat, const char *end_stat, git_vector *contents);
+#endif
+
+extern int git_win32_path_readlink_w(git_win32_path dest, const git_win32_path path);
+
 #endif

src/win32/posix.h

@@ -49,7 +49,15 @@ extern int p_ftruncate(int fd, git_off_t size);
  */
 extern int p_lstat_posixly(const char *filename, struct stat *buf);
 
-extern struct tm * p_localtime_r (const time_t *timer, struct tm *result);
-extern struct tm * p_gmtime_r (const time_t *timer, struct tm *result);
+extern struct tm * p_localtime_r(const time_t *timer, struct tm *result);
+extern struct tm * p_gmtime_r(const time_t *timer, struct tm *result);
+
+GIT_INLINE(time_t) filetime_to_time_t(const FILETIME *ft)
+{
+	long long winTime = ((long long)ft->dwHighDateTime << 32) + ft->dwLowDateTime;
+	winTime -= 116444736000000000LL; /* Windows to Unix Epoch conversion */
+	winTime /= 10000000;             /* Nano to seconds resolution */
+	return (time_t)winTime;
+}
 
 #endif

src/win32/posix_w32.c

@@ -130,88 +130,6 @@ int p_fsync(int fd)
 	return 0;
 }
 
-GIT_INLINE(time_t) filetime_to_time_t(const FILETIME *ft)
-{
-	long long winTime = ((long long)ft->dwHighDateTime << 32) + ft->dwLowDateTime;
-	winTime -= 116444736000000000LL; /* Windows to Unix Epoch conversion */
-	winTime /= 10000000;		 /* Nano to seconds resolution */
-	return (time_t)winTime;
-}
-
-static bool path_is_volume(wchar_t *target, size_t target_len)
-{
-	return (target_len && wcsncmp(target, L"\\??\\Volume{", 11) == 0);
-}
-
-/* On success, returns the length, in characters, of the path stored in dest.
- * On failure, returns a negative value. */
-static int readlink_w(
-	git_win32_path dest,
-	const git_win32_path path)
-{
-	BYTE buf[MAXIMUM_REPARSE_DATA_BUFFER_SIZE];
-	GIT_REPARSE_DATA_BUFFER *reparse_buf = (GIT_REPARSE_DATA_BUFFER *)buf;
-	HANDLE handle = NULL;
-	DWORD ioctl_ret;
-	wchar_t *target;
-	size_t target_len;
-
-	int error = -1;
-
-	handle = CreateFileW(path, GENERIC_READ,
-		FILE_SHARE_READ | FILE_SHARE_DELETE, NULL, OPEN_EXISTING,
-		FILE_FLAG_OPEN_REPARSE_POINT | FILE_FLAG_BACKUP_SEMANTICS, NULL);
-
-	if (handle == INVALID_HANDLE_VALUE) {
-		errno = ENOENT;
-		return -1;
-	}
-
-	if (!DeviceIoControl(handle, FSCTL_GET_REPARSE_POINT, NULL, 0,
-		reparse_buf, sizeof(buf), &ioctl_ret, NULL)) {
-		errno = EINVAL;
-		goto on_error;
-	}
-
-	switch (reparse_buf->ReparseTag) {
-	case IO_REPARSE_TAG_SYMLINK:
-		target = reparse_buf->SymbolicLinkReparseBuffer.PathBuffer +
-			(reparse_buf->SymbolicLinkReparseBuffer.SubstituteNameOffset / sizeof(WCHAR));
-		target_len = reparse_buf->SymbolicLinkReparseBuffer.SubstituteNameLength / sizeof(WCHAR);
-		break;
-	case IO_REPARSE_TAG_MOUNT_POINT:
-		target = reparse_buf->MountPointReparseBuffer.PathBuffer +
-			(reparse_buf->MountPointReparseBuffer.SubstituteNameOffset / sizeof(WCHAR));
-		target_len = reparse_buf->MountPointReparseBuffer.SubstituteNameLength / sizeof(WCHAR);
-		break;
-	default:
-		errno = EINVAL;
-		goto on_error;
-	}
-
-	if (path_is_volume(target, target_len)) {
-		/* This path is a reparse point that represents another volume mounted
-		 * at this location, it is not a symbolic link our input was canonical.
-		 */
-		errno = EINVAL;
-		error = -1;
-	} else if (target_len) {
-		/* The path may need to have a prefix removed. */
-		target_len = git_win32__canonicalize_path(target, target_len);
-
-		/* Need one additional character in the target buffer
-		 * for the terminating NULL. */
-		if (GIT_WIN_PATH_UTF16 > target_len) {
-			wcscpy(dest, target);
-			error = (int)target_len;
-		}
-	}
-
-on_error:
-	CloseHandle(handle);
-	return error;
-}
-
 #define WIN32_IS_WSEP(CH) ((CH) == L'/' || (CH) == L'\\')
 
 static int lstat_w(
@@ -249,7 +167,7 @@ static int lstat_w(
 		if (fdata.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) {
 			git_win32_path target;
 
-			if (readlink_w(target, path) >= 0) {
+			if (git_win32_path_readlink_w(target, path) >= 0) {
 				buf->st_mode = (buf->st_mode & ~S_IFMT) | S_IFLNK;
 
 				/* st_size gets the UTF-8 length of the target name, in bytes,
@@ -331,7 +249,7 @@ int p_readlink(const char *path, char *buf, size_t bufsiz)
 	 * we need to buffer the result on the stack. */
 
 	if (git_win32_path_from_utf8(path_w, path) < 0 ||
-		readlink_w(target_w, path_w) < 0 ||
+		git_win32_path_readlink_w(target_w, path_w) < 0 ||
 		(len = git_win32_path_to_utf8(target, target_w)) < 0)
 		return -1;