Fix checkout of large files to network shares on Windows XP

[git.git] / compat / mingw.c

diff --git a/compat/mingw.c b/compat/mingw.c
index f90a114b021d32c2ee1976bf51a82e87a81ea1cb..9a8e3365827d303c6513475726113a3952fe0040 100644 (file)
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -140,6 +140,23 @@ int mingw_open (const char *filename, int oflags, ...)
        return fd;
 }
 
+#undef write
+ssize_t mingw_write(int fd, const void *buf, size_t count)
+{
+       /*
+        * While write() calls to a file on a local disk are translated
+        * into WriteFile() calls with a maximum size of 64KB on Windows
+        * XP and 256KB on Vista, no such cap is placed on writes to
+        * files over the network on Windows XP.  Unfortunately, there
+        * seems to be a limit of 32MB-28KB on X64 and 64MB-32KB on x86;
+        * bigger writes fail on Windows XP.
+        * So we cap to a nice 31MB here to avoid write failures over
+        * the net without changing the number of WriteFile() calls in
+        * the local case.
+        */
+       return write(fd, buf, min(count, 31 * 1024 * 1024));
+}
+
 #undef fopen
 FILE *mingw_fopen (const char *filename, const char *otype)
 {