relative_path should honor dos-drive-prefix

diff --git a/path.c b/path.c
index 7f3324aeea8050c082f9bb52d769301cdede4805..0c16dc5fdb2153ba984d05cb5bfb23fd16a8f82d 100644 (file)
--- a/path.c
+++ b/path.c
@@ -441,6 +441,16 @@ int adjust_shared_perm(const char *path)
        return 0;
 }
 
+static int have_same_root(const char *path1, const char *path2)
+{
+       int is_abs1, is_abs2;
+
+       is_abs1 = is_absolute_path(path1);
+       is_abs2 = is_absolute_path(path2);
+       return (is_abs1 && is_abs2 && tolower(path1[0]) == tolower(path2[0])) ||
+              (!is_abs1 && !is_abs2);
+}
+
 /*
  * Give path as relative to prefix.
  *
@@ -461,6 +471,16 @@ const char *relative_path(const char *in, const char *prefix,
        else if (!prefix_len)
                return in;
 
+       if (have_same_root(in, prefix)) {
+               /* bypass dos_drive, for "c:" is identical to "C:" */
+               if (has_dos_drive_prefix(in)) {
+                       i = 2;
+                       j = 2;
+               }
+       } else {
+               return in;
+       }
+
        while (i < prefix_len && j < in_len && prefix[i] == in[j]) {
                if (is_dir_sep(prefix[i])) {
                        while (is_dir_sep(prefix[i]))