| 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. |
| 23 | * |
| 24 | * Whenever a chdir event occurs, that will update my_path (if it's relative) |
| 25 | * to adjust for the new cwd by freeing any existing string and allocating a |
| 26 | * new one. |
| 27 | * |
| 28 | * Registered functions are called in the order in which they were added. Note |
| 29 | * that there's currently no way to remove a function, so make sure that the |
| 30 | * data parameter remains valid for the rest of the program. |
| 31 | * |
| 32 | * The "name" argument is used only for printing trace output from |
| 33 | * $GIT_TRACE_SETUP. It may be NULL, but if non-NULL should point to |
| 34 | * storage which lasts as long as the registration is active. |
| 35 | */ |
| 36 | typedef void (*chdir_notify_callback)(const char *name, |
| 37 | const char *old_cwd, |
| 38 | const char *new_cwd, |
| 39 | void *data); |
| 40 | void chdir_notify_register(const char *name, chdir_notify_callback cb, void *data); |
| 41 | void chdir_notify_unregister(const char *name, chdir_notify_callback cb, |
| 42 | void *data); |
| 43 | |
| 44 | /* |
| 45 | * |
| 46 | * Callers that want to chdir: |
| 47 | * |
| 48 | * chdir_notify(new_path); |
| 49 | * |
| 50 | * to switch to the new path and notify any callbacks. |
| 51 | * |
| 52 | * Note that you don't need to chdir_notify() if you're just temporarily moving |
| 53 | * to a directory and back, as long as you don't call any subscribed code in |
| 54 | * between (but it should be safe to do so if you're unsure). |
| 55 | */ |
| 56 | int chdir_notify(const char *new_cwd); |
| 57 | |
| 58 | /* |
| 59 | * Reparent a relative path from old_root to new_root. For example: |
| 60 | * |
| 61 | * reparent_relative_path("/a", "/a/b", "b/rel"); |
| 62 | * |
| 63 | * would return the (newly allocated) string "rel". Note that we may return an |
| 64 | * absolute path in some cases (e.g., if the resulting path is not inside |
| 65 | * new_cwd). |
| 66 | */ |
| 67 | char *reparent_relative_path(const char *old_cwd, |
| 68 | const char *new_cwd, |
| 69 | const char *path); |
| 70 | |
| 71 | #endif /* CHDIR_NOTIFY_H */ |