hook: replace hook_list_clear() -> string_list_clear_func()

Replace the custom function with string_list_clear_func() which
is a more common pattern for clearing a string_list.

To be able to do this, rework hook_clear() into hook_free(), so
it can be passed to string_list_clear_func().

A slight complication is the need to keep a copy of the internal
cb data free() pointer, however I think it's worth it since the
API becomes cleaner, e.g. no more calls with NULL function args
like hook_list_clear(hooks, NULL).

In other words, the callers don't need to keep track of hook
internal state to determine when cleanup is necessary or not
(pass NULL) because each `struct hook` now owns its data_free
callback.

Suggested-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 14 insertions, 6 deletions

diff --git a/hook.h b/hook.h
index 965794a5b8..a56ac20ccf 100644
--- a/hook.h
+++ b/hook.h
@@ -7,6 +7,9 @@
 
 struct repository;
 
+typedef void (*hook_data_free_fn)(void *data);
+typedef void *(*hook_data_alloc_fn)(void *init_ctx);
+
 /**
  * Represents a hook command to be run.
  * Hooks can be:
@@ -41,10 +44,15 @@ struct hook {
 	 * Only useful when using `run_hooks_opt.feed_pipe`, otherwise ignore it.
 	 */
 	void *feed_pipe_cb_data;
-};
 
-typedef void (*hook_data_free_fn)(void *data);
-typedef void *(*hook_data_alloc_fn)(void *init_ctx);
+	/**
+	 * Callback to free `feed_pipe_cb_data`.
+	 *
+	 * It is called automatically and points to the `feed_pipe_cb_data_free`
+	 * provided via the `run_hook_opt` parameter.
+	 */
+	hook_data_free_fn data_free;
+};
 
 struct run_hooks_opt {
 	/* Environment vars to be set for each hook */
@@ -185,10 +193,10 @@ struct string_list *list_hooks(struct repository *r, const char *hookname,
 			       struct run_hooks_opt *options);
 
 /**
- * Frees the memory allocated for the hook list, including the `struct hook`
- * items and their internal state.
+ * Frees a struct hook stored as the util pointer of a string_list_item.
+ * Suitable for use as a string_list_clear_func_t callback.
  */
-void hook_list_clear(struct string_list *hooks, hook_data_free_fn cb_data_free);
+void hook_free(void *p, const char *str);
 
 /**
  * Frees the hook configuration cache stored in `struct repository`.