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| author | Junio C Hamano <gitster@pobox.com> | 2018-04-25 13:28:52 +0900 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2018-04-25 13:28:52 +0900 |
| commit | ff6eb825f0aa1f45230c10fbb0cf8d484c927c55 (patch) | |
| tree | e64f3f038b0f888c0ddc0a5c97e0d266068b82a4 /chdir-notify.h | |
| parent | 5d8da91e707668227464c9ba0e74b5fea1ee3b7e (diff) | |
| parent | fb9c2d27039a23457cb9710d86e00c51dfb910dc (diff) | |
| download | git-ff6eb825f0aa1f45230c10fbb0cf8d484c927c55.tar.gz | |
Merge branch 'jk/relative-directory-fix'
Some codepaths, including the refs API, get and keep relative
paths, that go out of sync when the process does chdir(2). The
chdir-notify API is introduced to let these codepaths adjust these
cached paths to the new current directory.
* jk/relative-directory-fix:
refs: use chdir_notify to update cached relative paths
set_work_tree: use chdir_notify
add chdir-notify API
trace.c: export trace_setup_key
set_git_dir: die when setenv() fails
Diffstat (limited to 'chdir-notify.h')
| -rw-r--r-- | chdir-notify.h | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/chdir-notify.h b/chdir-notify.h new file mode 100644 index 0000000000..366e4c1ee9 --- /dev/null +++ b/chdir-notify.h @@ -0,0 +1,73 @@ +#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 */ |