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/root_menu.c b/apps/root_menu.c
index 09c7efad9d..c94a4443e6 100644
--- a/apps/root_menu.c
+++ b/apps/root_menu.c
@@ -88,8 +88,9 @@ static int last_screen = GO_TO_ROOT; /* unfortunatly needed so we can resume
 
 
 static char current_track_path[MAX_PATH];
-static void rootmenu_track_changed_callback(void* param)
+static void rootmenu_track_changed_callback(unsigned short id, void* param)
 {
+    (void)id;
     struct mp3entry *id3 = ((struct track_event *)param)->id3;
     strlcpy(current_track_path, id3->path, MAX_PATH);
 }
@@ -746,7 +747,7 @@ void root_menu(void)
     if (global_settings.start_in_screen == 0)
         next_screen = (int)global_status.last_screen;
     else next_screen = global_settings.start_in_screen - 2;
-    add_event(PLAYBACK_EVENT_TRACK_CHANGE, false, rootmenu_track_changed_callback);
+    add_event(PLAYBACK_EVENT_TRACK_CHANGE, rootmenu_track_changed_callback);
 #ifdef HAVE_RTC_ALARM
     if ( rtc_check_alarm_started(true) )
     {