MinGW: 64-bit file offsets

The type 'off_t' should be used everywhere so that the bit-depth of that
type can be adjusted in the standard C library, and you just need to
recompile your program to benefit from the extended precision.

Only that it was not done that way in the MS runtime library.

This patch reroutes off_t to off64_t and provides the other necessary
changes so that finally, clones larger than 2 gigabyte work on Windows
(provided you are on a file system that allows files larger than 2gb).

Initial patch by Sickboy <sb@dev-heaven.net>.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Acked-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

compat/mingw.c

@@ -46,7 +46,8 @@ static int do_lstat(const char *file_name, struct stat *buf)
 		buf->st_uid = 0;
 		buf->st_nlink = 1;
 		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_size = fdata.nFileSizeLow |
+			(((off_t)fdata.nFileSizeHigh)<<32);
 		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));
@@ -101,15 +102,16 @@ int mingw_fstat(int fd, struct stat *buf)
 	}
 	/* direct non-file handles to MS's fstat() */
 	if (GetFileType(fh) != FILE_TYPE_DISK)
-		return fstat(fd, buf);
+		return _fstati64(fd, buf);
 
 	if (GetFileInformationByHandle(fh, &fdata)) {
 		buf->st_ino = 0;
 		buf->st_gid = 0;
 		buf->st_uid = 0;
 		buf->st_nlink = 1;
 		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_size = fdata.nFileSizeLow |
+			(((off_t)fdata.nFileSizeHigh)<<32);
 		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));

compat/mingw.h

@@ -163,11 +163,14 @@ int mingw_rename(const char*, const char*);
 /* Use mingw_lstat() instead of lstat()/stat() and
  * mingw_fstat() instead of fstat() on Windows.
  */
+#define off_t off64_t
+#define stat _stati64
+#define lseek _lseeki64
 int mingw_lstat(const char *file_name, struct stat *buf);
 int mingw_fstat(int fd, struct stat *buf);
 #define fstat mingw_fstat
 #define lstat mingw_lstat
-#define stat(x,y) mingw_lstat(x,y)
+#define stat64(x,y) mingw_lstat(x,y)
 
 int mingw_utime(const char *file_name, const struct utimbuf *times);
 #define utime mingw_utime