Merge branch 'dp/cywginstat'

* dp/cywginstat:
  cygwin: Use native Win32 API for stat
  mingw: move common functionality to win32.h
  add have_git_dir() function

Author: spearce

Documentation/config.txt

@@ -117,6 +117,15 @@ core.fileMode::
 	the working copy are ignored; useful on broken filesystems like FAT.
 	See linkgit:git-update-index[1]. True by default.
 
+core.ignoreCygwinFSTricks::
+	This option is only used by Cygwin implementation of Git. If false,
+	the Cygwin stat() and lstat() functions are used. This may be useful
+	if your repository consists of a few separate directories joined in
+	one hierarchy using Cygwin mount. If true, Git uses native Win32 API
+	whenever it is possible and falls back to Cygwin functions only to
+	handle symbol links. The native mode is more than twice faster than
+	normal Cygwin l/stat() functions. True by default.
+
 core.trustctime::
 	If false, the ctime differences between the index and the
 	working copy are ignored; useful when the inode change time

Makefile

@@ -346,6 +346,7 @@ LIB_H += cache.h
 LIB_H += cache-tree.h
 LIB_H += commit.h
 LIB_H += compat/mingw.h
+LIB_H += compat/cygwin.h
 LIB_H += csum-file.h
 LIB_H += decorate.h
 LIB_H += delta.h
@@ -748,6 +749,9 @@ ifeq ($(uname_S),HP-UX)
 	NO_SYS_SELECT_H = YesPlease
 	SNPRINTF_RETURNS_BOGUS = YesPlease
 endif
+ifneq (,$(findstring CYGWIN,$(uname_S)))
+	COMPAT_OBJS += compat/cygwin.o
+endif
 ifneq (,$(findstring MINGW,$(uname_S)))
 	NO_MMAP = YesPlease
 	NO_PREAD = YesPlease

cache.h

@@ -319,6 +319,7 @@ extern int is_bare_repository(void);
 extern int is_inside_git_dir(void);
 extern char *git_work_tree_cfg;
 extern int is_inside_work_tree(void);
+extern int have_git_dir(void);
 extern const char *get_git_dir(void);
 extern char *get_object_directory(void);
 extern char *get_index_file(void);

compat/cygwin.c

@@ -0,0 +1,127 @@
+#define WIN32_LEAN_AND_MEAN
+#include "../git-compat-util.h"
+#include "win32.h"
+#include "../cache.h" /* to read configuration */
+
+static inline void filetime_to_timespec(const FILETIME *ft, struct timespec *ts)
+{
+	long long winTime = ((long long)ft->dwHighDateTime << 32) +
+			ft->dwLowDateTime;
+	winTime -= 116444736000000000LL; /* Windows to Unix Epoch conversion */
+	/* convert 100-nsecond interval to seconds and nanoseconds */
+	ts->tv_sec = (time_t)(winTime/10000000);
+	ts->tv_nsec = (long)(winTime - ts->tv_sec*10000000LL) * 100;
+}
+
+#define size_to_blocks(s) (((s)+511)/512)
+
+/* do_stat is a common implementation for cygwin_lstat and cygwin_stat.
+ *
+ * To simplify its logic, in the case of cygwin symlinks, this implementation
+ * falls back to the cygwin version of stat/lstat, which is provided as the
+ * last argument.
+ */
+static int do_stat(const char *file_name, struct stat *buf, stat_fn_t cygstat)
+{
+	WIN32_FILE_ATTRIBUTE_DATA fdata;
+
+	if (file_name[0] == '/')
+		return cygstat (file_name, buf);
+
+	if (!(errno = get_file_attr(file_name, &fdata))) {
+		/*
+		 * If the system attribute is set and it is not a directory then
+		 * it could be a symbol link created in the nowinsymlinks mode.
+		 * Normally, Cygwin works in the winsymlinks mode, so this situation
+		 * is very unlikely. For the sake of simplicity of our code, let's
+		 * Cygwin to handle it.
+		 */
+		if ((fdata.dwFileAttributes & FILE_ATTRIBUTE_SYSTEM) &&
+		    !(fdata.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY))
+			return cygstat(file_name, buf);
+
+		/* fill out the stat structure */
+		buf->st_dev = buf->st_rdev = 0; /* not used by Git */
+		buf->st_ino = 0;
+		buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes);
+		buf->st_nlink = 1;
+		buf->st_uid = buf->st_gid = 0;
+#ifdef __CYGWIN_USE_BIG_TYPES__
+		buf->st_size = ((_off64_t)fdata.nFileSizeHigh << 32) +
+			fdata.nFileSizeLow;
+#else
+		buf->st_size = (off_t)fdata.nFileSizeLow;
+#endif
+		buf->st_blocks = size_to_blocks(buf->st_size);
+		filetime_to_timespec(&fdata.ftLastAccessTime, &buf->st_atim);
+		filetime_to_timespec(&fdata.ftLastWriteTime, &buf->st_mtim);
+		filetime_to_timespec(&fdata.ftCreationTime, &buf->st_ctim);
+		return 0;
+	} else if (errno == ENOENT) {
+		/*
+		 * In the winsymlinks mode (which is the default), Cygwin
+		 * emulates symbol links using Windows shortcut files. These
+		 * files are formed by adding .lnk extension. So, if we have
+		 * not found the specified file name, it could be that it is
+		 * a symbol link. Let's Cygwin to deal with that.
+		 */
+		return cygstat(file_name, buf);
+	}
+	return -1;
+}
+
+/* We provide our own lstat/stat functions, since the provided Cygwin versions
+ * of these functions are too slow. These stat functions are tailored for Git's
+ * usage, and therefore they are not meant to be complete and correct emulation
+ * of lstat/stat functionality.
+ */
+static int cygwin_lstat(const char *path, struct stat *buf)
+{
+	return do_stat(path, buf, lstat);
+}
+
+static int cygwin_stat(const char *path, struct stat *buf)
+{
+	return do_stat(path, buf, stat);
+}
+
+
+/*
+ * At start up, we are trying to determine whether Win32 API or cygwin stat
+ * functions should be used. The choice is determined by core.ignorecygwinfstricks.
+ * Reading this option is not always possible immediately as git_dir may be
+ * not be set yet. So until it is set, use cygwin lstat/stat functions.
+ */
+static int native_stat = 1;
+
+static int git_cygwin_config(const char *var, const char *value, void *cb)
+{
+	if (!strcmp(var, "core.ignorecygwinfstricks"))
+		native_stat = git_config_bool(var, value);
+	return 0;
+}
+
+static int init_stat(void)
+{
+	if (have_git_dir()) {
+		git_config(git_cygwin_config, NULL);
+		cygwin_stat_fn = native_stat ? cygwin_stat : stat;
+		cygwin_lstat_fn = native_stat ? cygwin_lstat : lstat;
+		return 0;
+	}
+	return 1;
+}
+
+static int cygwin_stat_stub(const char *file_name, struct stat *buf)
+{
+	return (init_stat() ? stat : *cygwin_stat_fn)(file_name, buf);
+}
+
+static int cygwin_lstat_stub(const char *file_name, struct stat *buf)
+{
+	return (init_stat() ? lstat : *cygwin_lstat_fn)(file_name, buf);
+}
+
+stat_fn_t cygwin_stat_fn = cygwin_stat_stub;
+stat_fn_t cygwin_lstat_fn = cygwin_lstat_stub;
+

compat/cygwin.h

@@ -0,0 +1,9 @@
+#include <sys/types.h>
+#include <sys/stat.h>
+
+typedef int (*stat_fn_t)(const char*, struct stat*);
+extern stat_fn_t cygwin_stat_fn;
+extern stat_fn_t cygwin_lstat_fn;
+
+#define stat(path, buf) (*cygwin_stat_fn)(path, buf)
+#define lstat(path, buf) (*cygwin_lstat_fn)(path, buf)

compat/mingw.c

@@ -1,4 +1,5 @@
 #include "../git-compat-util.h"
+#include "win32.h"
 #include "../strbuf.h"
 
 unsigned int _CRT_fmode = _O_BINARY;
@@ -39,46 +40,19 @@ static int do_lstat(const char *file_name, struct stat *buf)
 {
 	WIN32_FILE_ATTRIBUTE_DATA fdata;
 
-	if (GetFileAttributesExA(file_name, GetFileExInfoStandard, &fdata)) {
-		int fMode = S_IREAD;
-		if (fdata.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
-			fMode |= S_IFDIR;
-		else
-			fMode |= S_IFREG;
-		if (!(fdata.dwFileAttributes & FILE_ATTRIBUTE_READONLY))
-			fMode |= S_IWRITE;
-
+	if (!(errno = get_file_attr(file_name, &fdata))) {
 		buf->st_ino = 0;
 		buf->st_gid = 0;
 		buf->st_uid = 0;
 		buf->st_nlink = 1;
-		buf->st_mode = fMode;
+		buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes);
 		buf->st_size = fdata.nFileSizeLow; /* Can't use nFileSizeHigh, since it's not a stat64 */
 		buf->st_dev = buf->st_rdev = 0; /* not used by Git */
 		buf->st_atime = filetime_to_time_t(&(fdata.ftLastAccessTime));
 		buf->st_mtime = filetime_to_time_t(&(fdata.ftLastWriteTime));
 		buf->st_ctime = filetime_to_time_t(&(fdata.ftCreationTime));
-		errno = 0;
 		return 0;
 	}
-
-	switch (GetLastError()) {
-	case ERROR_ACCESS_DENIED:
-	case ERROR_SHARING_VIOLATION:
-	case ERROR_LOCK_VIOLATION:
-	case ERROR_SHARING_BUFFER_EXCEEDED:
-		errno = EACCES;
-		break;
-	case ERROR_BUFFER_OVERFLOW:
-		errno = ENAMETOOLONG;
-		break;
-	case ERROR_NOT_ENOUGH_MEMORY:
-		errno = ENOMEM;
-		break;
-	default:
-		errno = ENOENT;
-		break;
-	}
 	return -1;
 }
 
@@ -130,19 +104,11 @@ int mingw_fstat(int fd, struct stat *buf)
 		return fstat(fd, buf);
 
 	if (GetFileInformationByHandle(fh, &fdata)) {
-		int fMode = S_IREAD;
-		if (fdata.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
-			fMode |= S_IFDIR;
-		else
-			fMode |= S_IFREG;
-		if (!(fdata.dwFileAttributes & FILE_ATTRIBUTE_READONLY))
-			fMode |= S_IWRITE;
-
 		buf->st_ino = 0;
 		buf->st_gid = 0;
 		buf->st_uid = 0;
 		buf->st_nlink = 1;
-		buf->st_mode = fMode;
+		buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes);
 		buf->st_size = fdata.nFileSizeLow; /* Can't use nFileSizeHigh, since it's not a stat64 */
 		buf->st_dev = buf->st_rdev = 0; /* not used by Git */
 		buf->st_atime = filetime_to_time_t(&(fdata.ftLastAccessTime));

compat/win32.h

@@ -0,0 +1,34 @@
+/* common Win32 functions for MinGW and Cygwin */
+#include <windows.h>
+
+static inline int file_attr_to_st_mode (DWORD attr)
+{
+	int fMode = S_IREAD;
+	if (attr & FILE_ATTRIBUTE_DIRECTORY)
+		fMode |= S_IFDIR;
+	else
+		fMode |= S_IFREG;
+	if (!(attr & FILE_ATTRIBUTE_READONLY))
+		fMode |= S_IWRITE;
+	return fMode;
+}
+
+static inline int get_file_attr(const char *fname, WIN32_FILE_ATTRIBUTE_DATA *fdata)
+{
+	if (GetFileAttributesExA(fname, GetFileExInfoStandard, fdata))
+		return 0;
+
+	switch (GetLastError()) {
+	case ERROR_ACCESS_DENIED:
+	case ERROR_SHARING_VIOLATION:
+	case ERROR_LOCK_VIOLATION:
+	case ERROR_SHARING_BUFFER_EXCEEDED:
+		return EACCES;
+	case ERROR_BUFFER_OVERFLOW:
+		return ENAMETOOLONG;
+	case ERROR_NOT_ENOUGH_MEMORY:
+		return ENOMEM;
+	default:
+		return ENOENT;
+	}
+}

environment.c

@@ -80,6 +80,11 @@ int is_bare_repository(void)
 	return is_bare_repository_cfg && !get_git_work_tree();
 }
 
+int have_git_dir(void)
+{
+	return !!git_dir;
+}
+
 const char *get_git_dir(void)
 {
 	if (!git_dir)

git-compat-util.h

@@ -85,6 +85,7 @@
 #undef _XOPEN_SOURCE
 #include <grp.h>
 #define _XOPEN_SOURCE 600
+#include "compat/cygwin.h"
 #else
 #undef _ALL_SOURCE /* AIX 5.3L defines a struct list with _ALL_SOURCE. */
 #include <grp.h>