73 lines
2.5 KiB
C
73 lines
2.5 KiB
C
#ifndef CHDIR_NOTIFY_H
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#define CHDIR_NOTIFY_H
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/*
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* An API to let code "subscribe" to changes to the current working directory.
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* The general idea is that some code asks to be notified when the working
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* directory changes, and other code that calls chdir uses a special wrapper
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* that notifies everyone.
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*/
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/*
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* Callers who need to know about changes can do:
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*
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* void foo(const char *old_path, const char *new_path, void *data)
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* {
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* warning("switched from %s to %s!", old_path, new_path);
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* }
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* ...
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* chdir_notify_register("description", foo, data);
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*
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* In practice most callers will want to move a relative path to the new root;
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* they can use the reparent_relative_path() helper for that. If that's all
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* you're doing, you can also use the convenience function:
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*
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* chdir_notify_reparent("description", &my_path);
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*
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* Whenever a chdir event occurs, that will update my_path (if it's relative)
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* to adjust for the new cwd by freeing any existing string and allocating a
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* new one.
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*
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* Registered functions are called in the order in which they were added. Note
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* that there's currently no way to remove a function, so make sure that the
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* data parameter remains valid for the rest of the program.
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*
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* The "name" argument is used only for printing trace output from
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* $GIT_TRACE_SETUP. It may be NULL, but if non-NULL should point to
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* storage which lasts as long as the registration is active.
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*/
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typedef void (*chdir_notify_callback)(const char *name,
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const char *old_cwd,
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const char *new_cwd,
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void *data);
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void chdir_notify_register(const char *name, chdir_notify_callback cb, void *data);
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void chdir_notify_reparent(const char *name, char **path);
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/*
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*
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* Callers that want to chdir:
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*
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* chdir_notify(new_path);
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*
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* to switch to the new path and notify any callbacks.
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*
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* Note that you don't need to chdir_notify() if you're just temporarily moving
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* to a directory and back, as long as you don't call any subscribed code in
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* between (but it should be safe to do so if you're unsure).
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*/
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int chdir_notify(const char *new_cwd);
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/*
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* Reparent a relative path from old_root to new_root. For example:
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*
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* reparent_relative_path("/a", "/a/b", "b/rel");
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*
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* would return the (newly allocated) string "rel". Note that we may return an
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* absolute path in some cases (e.g., if the resulting path is not inside
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* new_cwd).
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*/
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char *reparent_relative_path(const char *old_cwd,
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const char *new_cwd,
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const char *path);
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#endif /* CHDIR_NOTIFY_H */
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