collsync.c

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/*  XMMS2 - X Music Multiplexer System
 *  Copyright (C) 2003-2009 XMMS2 Team
 *
 *  PLUGINS ARE NOT CONSIDERED TO BE DERIVED WORK !!!
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Lesser General Public License for more details.
 */


/** @file
 *  Manages the synchronization of collections to the database at 10 seconds
 *  after the last collections-change.
 */

#include "xmmspriv/xmms_collsync.h"
#include "xmms/xmms_log.h"
#include <glib.h>

static GThread *thread;
static GMutex *mutex;
static GCond *cond;
static gboolean want_sync = FALSE;
static gboolean keep_running = TRUE;

/**
 * Wait until no collections have changed for 10 seconds, then sync.
 * @internal
 */
static gpointer
do_loop (gpointer udata)
{
    xmms_coll_dag_t *dag = udata;
    GTimeVal time;

    g_mutex_lock (mutex);

    while (keep_running) {
        if (!want_sync) {
            g_cond_wait (cond, mutex);
        }

        /* Wait until no requests have been filed for 10 seconds. */
        while (keep_running && want_sync) {
            want_sync = FALSE;

            g_get_current_time (&time);
            g_time_val_add (&time, 10000000);

            g_cond_timed_wait (cond, mutex, &time);
        }

        if (keep_running) {
            /* The dag might be locked when calling schedule_sync, so we need to
             * unlock to avoid deadlocks */
            g_mutex_unlock (mutex);

            XMMS_DBG ("Syncing collections to database.");
            xmms_collection_sync (dag);

            g_mutex_lock (mutex);
        }
    }

    g_mutex_unlock (mutex);

    return NULL;
}

/**
 * Get the collection-to-database-synchronization thread running.
 */
void
xmms_coll_sync_init (xmms_coll_dag_t *dag)
{
    cond = g_cond_new ();
    mutex = g_mutex_new ();

    thread = g_thread_create (do_loop, dag, TRUE, NULL);
}

/**
 * Shutdown the collection-to-database-synchronization thread.
 */
void
xmms_coll_sync_shutdown ()
{
    g_mutex_lock (mutex);
    keep_running = FALSE;
    g_cond_signal (cond);
    g_mutex_unlock (mutex);

    g_thread_join (thread);

    g_mutex_free (mutex);
    g_cond_free (cond);
}

/**
 * Schedule a collection-to-database-synchronization in 10 seconds.
 */
void
xmms_coll_sync_schedule_sync ()
{
    g_mutex_lock (mutex);
    want_sync = TRUE;
    g_cond_signal (cond);
    g_mutex_unlock (mutex);
}