Add remove_path: a function to remove as much as possible of a path

The function has two potential users which both managed to get wrong
their implementations (the one in builtin-rm.c one has a memleak, and
builtin-merge-recursive.c scribles over its const argument).

Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

dir.c

@@ -837,3 +837,23 @@ void setup_standard_excludes(struct dir_struct *dir)
 	if (excludes_file && !access(excludes_file, R_OK))
 		add_excludes_from_file(dir, excludes_file);
 }
+
+int remove_path(const char *name)
+{
+	char *slash;
+
+	if (unlink(name) && errno != ENOENT)
+		return -1;
+
+	slash = strrchr(name, '/');
+	if (slash) {
+		char *dirs = xstrdup(name);
+		slash = dirs + (slash - name);
+		do {
+			*slash = '\0';
+		} while (rmdir(dirs) && (slash = strrchr(dirs, '/')));
+		free(dirs);
+	}
+	return 0;
+}
+

dir.h

@@ -81,4 +81,7 @@ extern int is_inside_dir(const char *dir);
 extern void setup_standard_excludes(struct dir_struct *dir);
 extern int remove_dir_recursively(struct strbuf *path, int only_empty);
 
+/* tries to remove the path with empty directories along it, ignores ENOENT */
+extern int remove_path(const char *path);
+
 #endif