Windows: Allow using UNC path for git repository

[efl: moved MinGW-specific part to compat/]
[jes: fixed compilation on non-Windows]

Eric Sunshine fixed mingw_offset_1st_component() to return consistently "foo"
for UNC "//machine/share/foo", cf
http://groups.google.com/group/msysgit/browse_thread/thread/c0af578549b5dda0

Author: Eric Sunshine <[email protected]>
Signed-off-by: Cezary Zawadka <[email protected]>
Signed-off-by: Eric Sunshine <[email protected]>
Signed-off-by: Erik Faye-Lund <[email protected]>
Signed-off-by: Johannes Schindelin <[email protected]>
Signed-off-by: Stepan Kasal <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: czawadka

cache.h

@@ -809,7 +809,6 @@ int normalize_path_copy(char *dst, const char *src);
 int longest_ancestor_length(const char *path, struct string_list *prefixes);
 char *strip_path_suffix(const char *path, const char *suffix);
 int daemon_avoid_alias(const char *path);
-int offset_1st_component(const char *path);
 
 /* object replacement */
 #define LOOKUP_REPLACE_OBJECT 1

compat/mingw.c

@@ -1823,3 +1823,27 @@ pid_t waitpid(pid_t pid, int *status, int options)
 	errno = EINVAL;
 	return -1;
 }
+
+int mingw_offset_1st_component(const char *path)
+{
+	int offset = 0;
+	if (has_dos_drive_prefix(path))
+		offset = 2;
+
+	/* unc paths */
+	else if (is_dir_sep(path[0]) && is_dir_sep(path[1])) {
+
+		/* skip server name */
+		char *pos = strpbrk(path + 2, "\\/");
+		if (!pos)
+			return 0; /* Error: malformed unc path */
+
+		do {
+			pos++;
+		} while (*pos && !is_dir_sep(*pos));
+
+		offset = pos - path;
+	}
+
+	return offset + is_dir_sep(path[offset]);
+}

compat/mingw.h

@@ -339,6 +339,8 @@ static inline char *mingw_find_last_dir_sep(const char *path)
 	return ret;
 }
 #define find_last_dir_sep mingw_find_last_dir_sep
+int mingw_offset_1st_component(const char *path);
+#define offset_1st_component mingw_offset_1st_component
 #define PATH_SEP ';'
 #define PRIuMAX "I64u"
 #define PRId64 "I64d"

git-compat-util.h

@@ -267,6 +267,10 @@ extern char *gitbasename(char *);
 #define has_dos_drive_prefix(path) 0
 #endif
 
+#ifndef offset_1st_component
+#define offset_1st_component(path) (is_dir_sep((path)[0]))
+#endif
+
 #ifndef is_dir_sep
 #define is_dir_sep(c) ((c) == '/')
 #endif

path.c

@@ -823,10 +823,3 @@ int daemon_avoid_alias(const char *p)
 		}
 	}
 }
-
-int offset_1st_component(const char *path)
-{
-	if (has_dos_drive_prefix(path))
-		return 2 + is_dir_sep(path[2]);
-	return is_dir_sep(path[0]);
-}