#ifndef CHDIR_NOTIFY_H

#define CHDIR_NOTIFY_H

/*

 * An API to let code "subscribe" to changes to the current working directory.

 * The general idea is that some code asks to be notified when the working

 * directory changes, and other code that calls chdir uses a special wrapper

 * that notifies everyone.

 */

/*

 * Callers who need to know about changes can do:

 *

 *   void foo(const char *old_path, const char *new_path, void *data)

 *   {

 *	warning("switched from %s to %s!", old_path, new_path);

 *   }

 *   ...

 *   chdir_notify_register("description", foo, data);

 *

 * In practice most callers will want to move a relative path to the new root;

 * they can use the reparent_relative_path() helper for that. If that's all

 * you're doing, you can also use the convenience function:

 *

 *   chdir_notify_reparent("description", &my_path);

 *

 * Whenever a chdir event occurs, that will update my_path (if it's relative)

 * to adjust for the new cwd by freeing any existing string and allocating a

 * new one.

 *

 * Registered functions are called in the order in which they were added. Note

 * that there's currently no way to remove a function, so make sure that the

 * data parameter remains valid for the rest of the program.

 *

 * The "name" argument is used only for printing trace output from

 * $GIT_TRACE_SETUP. It may be NULL, but if non-NULL should point to

 * storage which lasts as long as the registration is active.

 */

typedef void (*chdir_notify_callback)(const char *name,

				      const char *old_cwd,

				      const char *new_cwd,

				      void *data);

void chdir_notify_register(const char *name, chdir_notify_callback cb, void *data);

void chdir_notify_reparent(const char *name, char **path);

/*

 *

 * Callers that want to chdir:

 *

 *   chdir_notify(new_path);

 *

 * to switch to the new path and notify any callbacks.

 *

 * Note that you don't need to chdir_notify() if you're just temporarily moving

 * to a directory and back, as long as you don't call any subscribed code in

 * between (but it should be safe to do so if you're unsure).

 */

int chdir_notify(const char *new_cwd);

/*

 * Reparent a relative path from old_root to new_root. For example:

 *

 *   reparent_relative_path("/a", "/a/b", "b/rel");

 *

 * would return the (newly allocated) string "rel". Note that we may return an

 * absolute path in some cases (e.g., if the resulting path is not inside

 * new_cwd).

 */

char *reparent_relative_path(const char *old_cwd,

			     const char *new_cwd,

			     const char *path);

#endif /* CHDIR_NOTIFY_H */