Andrew's git - gitweb.git/blob

   1#ifndef CHDIR_NOTIFY_H
   2#define CHDIR_NOTIFY_H
   3
   4/*
   5 * An API to let code "subscribe" to changes to the current working directory.
   6 * The general idea is that some code asks to be notified when the working
   7 * directory changes, and other code that calls chdir uses a special wrapper
   8 * that notifies everyone.
   9 */
  10
  11/*
  12 * Callers who need to know about changes can do:
  13 *
  14 *   void foo(const char *old_path, const char *new_path, void *data)
  15 *   {
  16 *      warning("switched from %s to %s!", old_path, new_path);
  17 *   }
  18 *   ...
  19 *   chdir_notify_register("description", foo, data);
  20 *
  21 * In practice most callers will want to move a relative path to the new root;
  22 * they can use the reparent_relative_path() helper for that. If that's all
  23 * you're doing, you can also use the convenience function:
  24 *
  25 *   chdir_notify_reparent("description", &my_path);
  26 *
  27 * Whenever a chdir event occurs, that will update my_path (if it's relative)
  28 * to adjust for the new cwd by freeing any existing string and allocating a
  29 * new one.
  30 *
  31 * Registered functions are called in the order in which they were added. Note
  32 * that there's currently no way to remove a function, so make sure that the
  33 * data parameter remains valid for the rest of the program.
  34 *
  35 * The "name" argument is used only for printing trace output from
  36 * $GIT_TRACE_SETUP. It may be NULL, but if non-NULL should point to
  37 * storage which lasts as long as the registration is active.
  38 */
  39typedef void (*chdir_notify_callback)(const char *name,
  40                                      const char *old_cwd,
  41                                      const char *new_cwd,
  42                                      void *data);
  43void chdir_notify_register(const char *name, chdir_notify_callback cb, void *data);
  44void chdir_notify_reparent(const char *name, char **path);
  45
  46/*
  47 *
  48 * Callers that want to chdir:
  49 *
  50 *   chdir_notify(new_path);
  51 *
  52 * to switch to the new path and notify any callbacks.
  53 *
  54 * Note that you don't need to chdir_notify() if you're just temporarily moving
  55 * to a directory and back, as long as you don't call any subscribed code in
  56 * between (but it should be safe to do so if you're unsure).
  57 */
  58int chdir_notify(const char *new_cwd);
  59
  60/*
  61 * Reparent a relative path from old_root to new_root. For example:
  62 *
  63 *   reparent_relative_path("/a", "/a/b", "b/rel");
  64 *
  65 * would return the (newly allocated) string "rel". Note that we may return an
  66 * absolute path in some cases (e.g., if the resulting path is not inside
  67 * new_cwd).
  68 */
  69char *reparent_relative_path(const char *old_cwd,
  70                             const char *new_cwd,
  71                             const char *path);
  72
  73#endif /* CHDIR_NOTIFY_H */