mingw: add fallback for rmdir in case directory is in use

The same logic as for unlink and rename also applies to rmdir. For
example in case you have a shell open in a git controlled folder. This
will easily fail. So lets be nice for such cases as well.

Signed-off-by: Heiko Voigt <heiko.voigt@mahr.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

compat/mingw.c

@@ -225,6 +225,31 @@ int mingw_unlink(const char *pathname)
 	return ret;
 }
 
+#undef rmdir
+int mingw_rmdir(const char *pathname)
+{
+	int ret, tries = 0;
+
+	while ((ret = rmdir(pathname)) == -1 && tries < ARRAY_SIZE(delay)) {
+		if (!is_file_in_use_error(GetLastError()))
+			break;
+		/*
+		 * We assume that some other process had the source or
+		 * destination file open at the wrong moment and retry.
+		 * In order to give the other process a higher chance to
+		 * complete its operation, we give up our time slice now.
+		 * If we have to retry again, we do sleep a bit.
+		 */
+		Sleep(delay[tries]);
+		tries++;
+	}
+	while (ret == -1 && is_file_in_use_error(GetLastError()) &&
+	       ask_yes_no_if_possible("Deletion of directory '%s' failed. "
+			"Should I try again?", pathname))
+	       ret = rmdir(pathname);
+	return ret;
+}
+
 #undef open
 int mingw_open (const char *filename, int oflags, ...)
 {

compat/mingw.h

@@ -175,6 +175,9 @@ int link(const char *oldpath, const char *newpath);
 int mingw_unlink(const char *pathname);
 #define unlink mingw_unlink
 
+int mingw_rmdir(const char *path);
+#define rmdir mingw_rmdir
+
 int mingw_open (const char *filename, int oflags, ...);
 #define open mingw_open