Fix git-apply with -p greater than 1

Fix the case when the patch is a rename or mode-change only
and -p is used with a value greater than one.
The git_header_name function did not remove more than one path
component.

Signed-off-by: Federico Cuello <fedux@lugmen.org.ar>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/apply.c

@@ -919,28 +919,28 @@ static int gitdiff_newfile(const char *line, struct patch *patch)
 static int gitdiff_copysrc(const char *line, struct patch *patch)
 {
 	patch->is_copy = 1;
-	patch->old_name = find_name(line, NULL, 0, 0);
+	patch->old_name = find_name(line, NULL, p_value ? p_value - 1 : 0, 0);
 	return 0;
 }
 
 static int gitdiff_copydst(const char *line, struct patch *patch)
 {
 	patch->is_copy = 1;
-	patch->new_name = find_name(line, NULL, 0, 0);
+	patch->new_name = find_name(line, NULL, p_value ? p_value - 1 : 0, 0);
 	return 0;
 }
 
 static int gitdiff_renamesrc(const char *line, struct patch *patch)
 {
 	patch->is_rename = 1;
-	patch->old_name = find_name(line, NULL, 0, 0);
+	patch->old_name = find_name(line, NULL, p_value ? p_value - 1 : 0, 0);
 	return 0;
 }
 
 static int gitdiff_renamedst(const char *line, struct patch *patch)
 {
 	patch->is_rename = 1;
-	patch->new_name = find_name(line, NULL, 0, 0);
+	patch->new_name = find_name(line, NULL, p_value ? p_value - 1 : 0, 0);
 	return 0;
 }
 
@@ -1025,7 +1025,7 @@ static char *git_header_name(char *line, int llen)
 {
 	const char *name;
 	const char *second = NULL;
-	size_t len;
+	size_t len, line_len;
 
 	line += strlen("diff --git ");
 	llen -= strlen("diff --git ");
@@ -1125,22 +1125,22 @@ static char *git_header_name(char *line, int llen)
 	 * Accept a name only if it shows up twice, exactly the same
 	 * form.
 	 */
+	second = strchr(name, '\n');
+	if (!second)
+		return NULL;
+	line_len = second - name;
 	for (len = 0 ; ; len++) {
 		switch (name[len]) {
 		default:
 			continue;
 		case '\n':
 			return NULL;
 		case '\t': case ' ':
-			second = name+len;
-			for (;;) {
-				char c = *second++;
-				if (c == '\n')
-					return NULL;
-				if (c == '/')
-					break;
-			}
-			if (second[len] == '\n' && !memcmp(name, second, len)) {
+			second = stop_at_slash(name + len, line_len - len);
+			if (!second)
+				return NULL;
+			second++;
+			if (second[len] == '\n' && !strncmp(name, second, len)) {
 				return xmemdupz(name, len);
 			}
 		}