1 files changed, 35 insertions, 28 deletions

diff --git a/dir.c b/dir.c
index 08281d2ef7..6c0d782579 100644
--- a/dir.c
+++ b/dir.c
@@ -34,49 +34,54 @@ int fnmatch_icase(const char *pattern, const char *string, int flags)
 	return fnmatch(pattern, string, flags | (ignore_case ? FNM_CASEFOLD : 0));
 }
 
-static int common_prefix(const char **pathspec)
+static size_t common_prefix_len(const char **pathspec)
 {
-	const char *path, *slash, *next;
-	int prefix;
+	const char *n, *first;
+	size_t max = 0;
 
 	if (!pathspec)
-		return 0;
+		return max;
+
+	first = *pathspec;
+	while ((n = *pathspec++)) {
+		size_t i, len = 0;
+		for (i = 0; first == n || i < max; i++) {
+			char c = n[i];
+			if (!c || c != first[i] || is_glob_special(c))
+				break;
+			if (c == '/')
+				len = i + 1;
+		}
+		if (first == n || len < max) {
+			max = len;
+			if (!max)
+				break;
+		}
+	}
+	return max;
+}
 
-	path = *pathspec;
-	slash = strrchr(path, '/');
-	if (!slash)
-		return 0;
+/*
+ * Returns a copy of the longest leading path common among all
+ * pathspecs.
+ */
+char *common_prefix(const char **pathspec)
+{
+	unsigned long len = common_prefix_len(pathspec);
 
-	/*
-	 * The first 'prefix' characters of 'path' are common leading
-	 * path components among the pathspecs we have seen so far,
-	 * including the trailing slash.
-	 */
-	prefix = slash - path + 1;
-	while ((next = *++pathspec) != NULL) {
-		int len, last_matching_slash = -1;
-		for (len = 0; len < prefix && next[len] == path[len]; len++)
-			if (next[len] == '/')
-				last_matching_slash = len;
-		if (len == prefix)
-			continue;
-		if (last_matching_slash < 0)
-			return 0;
-		prefix = last_matching_slash + 1;
-	}
-	return prefix;
+	return len ? xmemdupz(*pathspec, len) : NULL;
 }
 
 int fill_directory(struct dir_struct *dir, const char **pathspec)
 {
 	const char *path;
-	int len;
+	size_t len;
 
 	/*
 	 * Calculate common prefix for the pathspec, and
 	 * use that to optimize the directory walk
 	 */
-	len = common_prefix(pathspec);
+	len = common_prefix_len(pathspec);
 	path = "";
 
 	if (len)
@@ -84,6 +89,8 @@ int fill_directory(struct dir_struct *dir, const char **pathspec)
 
 	/* Read the directory and prune it */
 	read_directory(dir, path, len, pathspec);
+	if (*path)
+		free((char *)path);
 	return len;
 }