events: Rework event subsystem (add_event, send_event) to be more versatile.

add_event_ex is added that takes an extra user_data pointer. This pointer is
passed to the callback (add_event and add_event_ex have slightly different
callbacks types). All callbacks also get the event id passed. Events added
with add_event_ex must be removed with remove_event_ex because the user_data
pointer must match in addition to the callback pointer.

On the other add_event is simplified to omit the oneshort parameter which
was almost always false (still there with add_event_ex).

As a side effect the ata_idle_notify callbacks are changed as well, they
do not take a data parameter anymore which was always NULL anyway.

This commit also adds some documentation to events.h

Change-Id: I13e29a0f88ef908f175b376d83550f9e0231f772

1 files changed, 3 insertions, 2 deletions

diff --git a/apps/iap/iap-core.c b/apps/iap/iap-core.c
index 7226a908c5..4fa9c09a47 100644
--- a/apps/iap/iap-core.c
+++ b/apps/iap/iap-core.c
@@ -349,8 +349,9 @@ static void iap_thread(void)
 }
 
 /* called by playback when the next track starts */
-static void iap_track_changed(void *ignored)
+static void iap_track_changed(unsigned short id, void *ignored)
 {
+    (void)id;
     (void)ignored;
     if ((interface_state == IST_EXTENDED) && device.do_notify) {
         long playlist_pos = playlist_next(0);
@@ -401,7 +402,7 @@ static void iap_start(void)
     if (!tid)
         panicf("Could not create iap thread");
     timeout_register(&iap_task_tmo, iap_task, MS_TO_TICKS(100), (intptr_t)NULL);
-    add_event(PLAYBACK_EVENT_TRACK_CHANGE, false, iap_track_changed);
+    add_event(PLAYBACK_EVENT_TRACK_CHANGE, iap_track_changed);
 
     /* Since we cannot allocate memory while in interrupt context
      * post a message to our own queue to get that done