/***************************************************************************** * event.c: New libvlc event control API ***************************************************************************** * Copyright (C) 2007 the VideoLAN team * $Id $ * * Authors: Filippo Carone <filippo@carone.org> * Pierre d'Herbemont <pdherbemont # videolan.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA. *****************************************************************************/ #include <assert.h> #include <vlc/libvlc.h> #include "libvlc_internal.h" #include "event_internal.h" struct queue_elmt { libvlc_event_listener_t listener; libvlc_event_t event; struct queue_elmt * next; }; struct libvlc_event_async_queue { struct queue_elmt * elements; vlc_mutex_t lock; vlc_cond_t signal; vlc_thread_t thread; bool is_idle; vlc_cond_t signal_idle; vlc_threadvar_t is_asynch_dispatch_thread_var; }; /* * Utilities */ static void* event_async_loop(void * arg); static inline struct libvlc_event_async_queue * queue(libvlc_event_manager_t * p_em) { return p_em->async_event_queue; } static inline bool is_queue_initialized(libvlc_event_manager_t * p_em) { return queue(p_em) != NULL; } static inline bool current_thread_is_asynch_thread(libvlc_event_manager_t * p_em) { return vlc_threadvar_get(queue(p_em)->is_asynch_dispatch_thread_var); } /* Lock must be held */ static void push(libvlc_event_manager_t * p_em, libvlc_event_listener_t * listener, libvlc_event_t * event) { #ifndef NDEBUG static const long MaxQueuedItem = 300000; long count = 0; #endif struct queue_elmt * elmt = malloc(sizeof(struct queue_elmt)); elmt->listener = *listener; elmt->event = *event; elmt->next = NULL; /* Append to the end of the queue */ struct queue_elmt * iter = queue(p_em)->elements; if(!iter) { queue(p_em)->elements = elmt; return; } while (iter->next) { iter = iter->next; #ifndef NDEBUG if(count++ > MaxQueuedItem) { fprintf(stderr, "Warning: libvlc event overflow.\n"); abort(); } #endif } iter->next = elmt; } static inline void queue_lock(libvlc_event_manager_t * p_em) { vlc_mutex_lock(&queue(p_em)->lock); } static inline void queue_unlock(libvlc_event_manager_t * p_em) { vlc_mutex_unlock(&queue(p_em)->lock); } /* Lock must be held */ static bool pop(libvlc_event_manager_t * p_em, libvlc_event_listener_t * listener, libvlc_event_t * event) { if(!queue(p_em)->elements) return false; /* No elements */ *listener = queue(p_em)->elements->listener; *event = queue(p_em)->elements->event; struct queue_elmt * elmt = queue(p_em)->elements; queue(p_em)->elements = elmt->next; free(elmt); return true; } /* Lock must be held */ static void pop_listener(libvlc_event_manager_t * p_em, libvlc_event_listener_t * listener) { struct queue_elmt * iter = queue(p_em)->elements; struct queue_elmt * prev = NULL; while (iter) { if(listeners_are_equal(&iter->listener, listener)) { struct queue_elmt * to_delete = iter; if(!prev) queue(p_em)->elements = to_delete->next; else prev->next = to_delete->next; iter = to_delete->next; free(to_delete); } else { prev = iter; iter = iter->next; } } } /************************************************************************** * libvlc_event_async_fini (internal) : * * Destroy what might have been created by. **************************************************************************/ void libvlc_event_async_fini(libvlc_event_manager_t * p_em) { if(!is_queue_initialized(p_em)) return; if(current_thread_is_asynch_thread(p_em)) { fprintf(stderr, "*** Error: releasing the last reference of the observed object from its callback thread is not (yet!) supported\n"); abort(); } vlc_thread_t thread = queue(p_em)->thread; if(thread) { vlc_cancel(thread); vlc_join(thread, NULL); } vlc_mutex_destroy(&queue(p_em)->lock); vlc_cond_destroy(&queue(p_em)->signal); vlc_cond_destroy(&queue(p_em)->signal_idle); vlc_threadvar_delete(&queue(p_em)->is_asynch_dispatch_thread_var); struct queue_elmt * iter = queue(p_em)->elements; while (iter) { struct queue_elmt * elemt_to_delete = iter; iter = iter->next; free(elemt_to_delete); } free(queue(p_em)); } /************************************************************************** * libvlc_event_async_init (private) : * * Destroy what might have been created by. **************************************************************************/ static void libvlc_event_async_init(libvlc_event_manager_t * p_em) { p_em->async_event_queue = calloc(1, sizeof(struct libvlc_event_async_queue)); int error = vlc_clone (&queue(p_em)->thread, event_async_loop, p_em, VLC_THREAD_PRIORITY_LOW); if(error) { free(p_em->async_event_queue); p_em->async_event_queue = NULL; return; } vlc_mutex_init(&queue(p_em)->lock); vlc_cond_init(&queue(p_em)->signal); vlc_cond_init(&queue(p_em)->signal_idle); error = vlc_threadvar_create(&queue(p_em)->is_asynch_dispatch_thread_var, NULL); assert(!error); } /************************************************************************** * libvlc_event_async_ensure_listener_removal (internal) : * * Make sure no more message will be issued to the listener. **************************************************************************/ void libvlc_event_async_ensure_listener_removal(libvlc_event_manager_t * p_em, libvlc_event_listener_t * listener) { if(!is_queue_initialized(p_em)) return; queue_lock(p_em); pop_listener(p_em, listener); // Wait for the asynch_loop to have processed all events. if(!current_thread_is_asynch_thread(p_em)) { while(!queue(p_em)->is_idle) vlc_cond_wait(&queue(p_em)->signal_idle, &queue(p_em)->lock); } queue_unlock(p_em); } /************************************************************************** * libvlc_event_async_dispatch (internal) : * * Send an event in an asynchronous way. **************************************************************************/ void libvlc_event_async_dispatch(libvlc_event_manager_t * p_em, libvlc_event_listener_t * listener, libvlc_event_t * event) { // We do a lazy init here, to prevent constructing the thread when not needed. vlc_mutex_lock(&p_em->object_lock); if(!queue(p_em)) libvlc_event_async_init(p_em); vlc_mutex_unlock(&p_em->object_lock); queue_lock(p_em); push(p_em, listener, event); vlc_cond_signal(&queue(p_em)->signal); queue_unlock(p_em); } /************************************************************************** * event_async_loop (private) : * * Send queued events. **************************************************************************/ static void * event_async_loop(void * arg) { libvlc_event_manager_t * p_em = arg; libvlc_event_listener_t listener; libvlc_event_t event; vlc_threadvar_set(queue(p_em)->is_asynch_dispatch_thread_var, p_em); queue_lock(p_em); while (true) { int has_listener = pop(p_em, &listener, &event); if (has_listener) { queue_unlock(p_em); listener.pf_callback(&event, listener.p_user_data); // This might edit the queue queue_lock(p_em); } else { queue(p_em)->is_idle = true; mutex_cleanup_push(&queue(p_em)->lock); vlc_cond_broadcast(&queue(p_em)->signal_idle); // We'll be idle vlc_cond_wait(&queue(p_em)->signal, &queue(p_em)->lock); vlc_cleanup_pop(); queue(p_em)->is_idle = false; } } queue_unlock(p_em); return NULL; }