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2b5ed373 JK |
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 | */ | |
39 | typedef void (*chdir_notify_callback)(const char *name, | |
40 | const char *old_cwd, | |
41 | const char *new_cwd, | |
42 | void *data); | |
43 | void chdir_notify_register(const char *name, chdir_notify_callback cb, void *data); | |
44 | void 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 | */ | |
58 | int 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 | */ | |
69 | char *reparent_relative_path(const char *old_cwd, | |
70 | const char *new_cwd, | |
71 | const char *path); | |
72 | ||
73 | #endif /* CHDIR_NOTIFY_H */ |