gstcollectpads.c

gnash 在pc和嵌入式下开发需要的源码

/* GStreamer
 * Copyright (C) 2005 Wim Taymans <[e-mail]>
 *
 * gstcollectpads.c:
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */
/**
 * SECTION:gstcollectpads
 * @short_description: manages a set of pads that operate in collect mode
 * @see_also:
 *
 * Manages a set of pads that operate in collect mode. This means that control
 * is given to the manager of this object when all pads have data.
 * <itemizedlist>
 *   <listitem><para>
 *     Collectpads are created with gst_collect_pads_new(). A callback should then
 *     be installed with gst_collect_pads_set_function (). 
 *   </para></listitem>
 *   <listitem><para>
 *     Pads are added to the collection with gst_collect_pads_add_pad()/
 *     gst_collect_pads_remove_pad(). The pad
 *     has to be a sinkpad. The chain and event functions of the pad are
 *     overridden. The element_private of the pad is used to store
 *     private information for the collectpads.
 *   </para></listitem>
 *   <listitem><para>
 *     For each pad, data is queued in the _chain function or by
 *     performing a pull_range.
 *   </para></listitem>
 *   <listitem><para>
 *     When data is queued on all pads, the callback function is called.
 *   </para></listitem>
 *   <listitem><para>
 *     Data can be dequeued from the pad with the gst_collect_pads_pop() method.
 *     One can peek at the data with the gst_collect_pads_peek() function.
 *     These functions will return NULL if the pad received an EOS event. When all
 *     pads return NULL from a gst_collect_pads_peek(), the element can emit an EOS
 *     event itself.
 *   </para></listitem>
 *   <listitem><para>
 *     Data can also be dequeued in byte units using the gst_collect_pads_available(), 
 *     gst_collect_pads_read() and gst_collect_pads_flush() calls.
 *   </para></listitem>
 *   <listitem><para>
 *     Elements should call gst_collect_pads_start() and gst_collect_pads_stop() in
 *     their state change functions to start and stop the processing of the collecpads.
 *     The gst_collect_pads_stop() call should be called before calling the parent
 *     element state change function in the PAUSED_TO_READY state change to ensure
 *     no pad is blocked and the element can finish streaming.
 *   </para></listitem>
 *   <listitem><para>
 *     gst_collect_pads_collect() and gst_collect_pads_collect_range() can be used by
 *     elements that start a #GstTask to drive the collect_pads. This feature is however
 *     not yet implemented.
 *   </para></listitem>
 * </itemizedlist>
 *
 * Last reviewed on 2006-05-10 (0.10.6)
 */

#include "gstcollectpads.h"

GST_DEBUG_CATEGORY_STATIC (collect_pads_debug);
#define GST_CAT_DEFAULT collect_pads_debug

GST_BOILERPLATE (GstCollectPads, gst_collect_pads, GstObject, GST_TYPE_OBJECT);

static void gst_collect_pads_clear (GstCollectPads * pads,
    GstCollectData * data);
static GstFlowReturn gst_collect_pads_chain (GstPad * pad, GstBuffer * buffer);
static gboolean gst_collect_pads_event (GstPad * pad, GstEvent * event);
static void gst_collect_pads_finalize (GObject * object);
static void gst_collect_pads_init (GstCollectPads * pads,
    GstCollectPadsClass * g_class);
static void ref_data (GstCollectData * data);
static void unref_data (GstCollectData * data);

static void
gst_collect_pads_base_init (gpointer g_class)
{
  GST_DEBUG_CATEGORY_INIT (collect_pads_debug, "collectpads", 0,
      "GstCollectPads");
}

static void
gst_collect_pads_class_init (GstCollectPadsClass * klass)
{
  GObjectClass *gobject_class = (GObjectClass *) klass;

  gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_collect_pads_finalize);
}

static void
gst_collect_pads_init (GstCollectPads * pads, GstCollectPadsClass * g_class)
{
  pads->cond = g_cond_new ();
  pads->data = NULL;
  pads->cookie = 0;
  pads->numpads = 0;
  pads->queuedpads = 0;
  pads->eospads = 0;
  pads->started = FALSE;

  /* members to manage the pad list */
  pads->abidata.ABI.pad_lock = g_mutex_new ();
  pads->abidata.ABI.pad_cookie = 0;
  pads->abidata.ABI.pad_list = NULL;
}

static void
gst_collect_pads_finalize (GObject * object)
{
  GSList *collected;
  GstCollectPads *pads = GST_COLLECT_PADS (object);

  GST_DEBUG ("finalize");

  g_cond_free (pads->cond);
  g_mutex_free (pads->abidata.ABI.pad_lock);

  /* Remove pads */
  collected = pads->abidata.ABI.pad_list;
  for (; collected; collected = g_slist_next (collected)) {
    GstCollectData *pdata = (GstCollectData *) collected->data;

    unref_data (pdata);
  }
  /* Free pads list */
  g_slist_foreach (pads->data, (GFunc) unref_data, NULL);
  g_slist_free (pads->data);
  g_slist_free (pads->abidata.ABI.pad_list);

  G_OBJECT_CLASS (parent_class)->finalize (object);
}

/**
 * gst_collect_pads_new:
 *
 * Create a new instance of #GstCollectsPads.
 *
 * Returns: a new #GstCollectPads, or NULL in case of an error.
 *
 * MT safe.
 */
GstCollectPads *
gst_collect_pads_new (void)
{
  GstCollectPads *newcoll;

  newcoll = g_object_new (GST_TYPE_COLLECT_PADS, NULL);

  return newcoll;
}

/**
 * gst_collect_pads_set_function:
 * @pads: the collectspads to use
 * @func: the function to set
 * @user_data: user data passed to the function
 *
 * Set the callback function and user data that will be called when
 * all the pads added to the collection have buffers queued.
 *
 * MT safe.
 */
void
gst_collect_pads_set_function (GstCollectPads * pads,
    GstCollectPadsFunction func, gpointer user_data)
{
  g_return_if_fail (pads != NULL);
  g_return_if_fail (GST_IS_COLLECT_PADS (pads));

  GST_OBJECT_LOCK (pads);
  pads->func = func;
  pads->user_data = user_data;
  GST_OBJECT_UNLOCK (pads);
}

static void
ref_data (GstCollectData * data)
{
  g_assert (data != NULL);

  g_atomic_int_inc (&(data->abidata.ABI.refcount));
}

static void
unref_data (GstCollectData * data)
{
  GstCollectDataDestroyNotify destroy_notify;

  g_assert (data != NULL);
  g_assert (data->abidata.ABI.refcount > 0);

  if (!g_atomic_int_dec_and_test (&(data->abidata.ABI.refcount)))
    return;

  /* FIXME: Ugly hack as we can't add more fields to GstCollectData */
  destroy_notify = (GstCollectDataDestroyNotify)
      g_object_get_data (G_OBJECT (data->pad),
      "gst-collect-data-destroy-notify");

  if (destroy_notify)
    destroy_notify (data);

  g_object_unref (data->pad);
  if (data->buffer) {
    gst_buffer_unref (data->buffer);
  }
  g_free (data);
}

/**
 * gst_collect_pads_add_pad:
 * @pads: the collectspads to use
 * @pad: the pad to add
 * @size: the size of the returned #GstCollectData structure
 *
 * Add a pad to the collection of collect pads. The pad has to be
 * a sinkpad. The refcount of the pad is incremented. Use
 * gst_collect_pads_remove_pad() to remove the pad from the collection
 * again.
 *
 * You specify a size for the returned #GstCollectData structure
 * so that you can use it to store additional information.
 *
 * The pad will be automatically activated in push mode when @pads is
 * started.
 *
 * This function calls gst_collect_pads_add_pad() passing a value of NULL
 * for destroy_notify.
 *
 * Returns: a new #GstCollectData to identify the new pad. Or NULL
 *   if wrong parameters are supplied.
 *
 * MT safe.
 */
GstCollectData *
gst_collect_pads_add_pad (GstCollectPads * pads, GstPad * pad, guint size)
{
  return gst_collect_pads_add_pad_full (pads, pad, size, NULL);
}

/**
 * gst_collect_pads_add_pad_full:
 * @pads: the collectspads to use
 * @pad: the pad to add
 * @size: the size of the returned #GstCollectData structure
 * @destroy_notify: function to be called before the returned #GstCollectData
 * structure is freed
 *
 * Add a pad to the collection of collect pads. The pad has to be
 * a sinkpad. The refcount of the pad is incremented. Use
 * gst_collect_pads_remove_pad() to remove the pad from the collection
 * again.
 *
 * You specify a size for the returned #GstCollectData structure
 * so that you can use it to store additional information.
 *
 * You can also specify a #GstCollectDataDestroyNotify that will be called
 * just before the #GstCollectData structure is freed. It is passed the
 * pointer to the structure and should free any custom memory and resources
 * allocated for it.
 *
 * The pad will be automatically activated in push mode when @pads is
 * started.
 *
 * Since: 0.10.12
 *
 * Returns: a new #GstCollectData to identify the new pad. Or NULL
 *   if wrong parameters are supplied.
 *
 * MT safe.
 */
GstCollectData *
gst_collect_pads_add_pad_full (GstCollectPads * pads, GstPad * pad, guint size,
    GstCollectDataDestroyNotify destroy_notify)
{
  GstCollectData *data;

  g_return_val_if_fail (pads != NULL, NULL);
  g_return_val_if_fail (GST_IS_COLLECT_PADS (pads), NULL);
  g_return_val_if_fail (pad != NULL, NULL);
  g_return_val_if_fail (GST_PAD_IS_SINK (pad), NULL);
  g_return_val_if_fail (size >= sizeof (GstCollectData), NULL);

  GST_DEBUG ("adding pad %s:%s", GST_DEBUG_PAD_NAME (pad));

  data = g_malloc0 (size);
  data->collect = pads;
  data->pad = gst_object_ref (pad);
  data->buffer = NULL;
  data->pos = 0;
  gst_segment_init (&data->segment, GST_FORMAT_UNDEFINED);
  data->abidata.ABI.flushing = FALSE;
  data->abidata.ABI.new_segment = FALSE;
  data->abidata.ABI.eos = FALSE;
  data->abidata.ABI.refcount = 1;

  /* FIXME: Ugly hack as we can't add more fields to GstCollectData */
  g_object_set_data (G_OBJECT (pad), "gst-collect-data-destroy-notify",
      (void *) destroy_notify);

  GST_COLLECT_PADS_PAD_LOCK (pads);
  GST_OBJECT_LOCK (pad);
  gst_pad_set_element_private (pad, data);
  GST_OBJECT_UNLOCK (pad);
  pads->abidata.ABI.pad_list =
      g_slist_append (pads->abidata.ABI.pad_list, data);
  gst_pad_set_chain_function (pad, GST_DEBUG_FUNCPTR (gst_collect_pads_chain));
  gst_pad_set_event_function (pad, GST_DEBUG_FUNCPTR (gst_collect_pads_event));
  /* activate the pad when needed */
  if (pads->started)
    gst_pad_set_active (pad, TRUE);
  pads->abidata.ABI.pad_cookie++;
  GST_COLLECT_PADS_PAD_UNLOCK (pads);

  return data;
}

static gint
find_pad (GstCollectData * data, GstPad * pad)
{
  if (data->pad == pad)
    return 0;
  return 1;
}

/**
 * gst_collect_pads_remove_pad:
 * @pads: the collectspads to use
 * @pad: the pad to remove
 *
 * Remove a pad from the collection of collect pads. This function will also
 * free the #GstCollectData and all the resources that were allocated with 
 * gst_collect_pads_add_pad().
 *
 * The pad will be deactivated automatically when @pads is stopped.
 *
 * Returns: %TRUE if the pad could be removed.
 *
 * MT safe.
 */
gboolean
gst_collect_pads_remove_pad (GstCollectPads * pads, GstPad * pad)
{
  GstCollectData *data;
  GSList *list;

  g_return_val_if_fail (pads != NULL, FALSE);
  g_return_val_if_fail (GST_IS_COLLECT_PADS (pads), FALSE);
  g_return_val_if_fail (pad != NULL, FALSE);
  g_return_val_if_fail (GST_IS_PAD (pad), FALSE);

  GST_DEBUG ("removing pad %s:%s", GST_DEBUG_PAD_NAME (pad));

  GST_COLLECT_PADS_PAD_LOCK (pads);
  list =
      g_slist_find_custom (pads->abidata.ABI.pad_list, pad,
      (GCompareFunc) find_pad);
  if (!list)
    goto unknown_pad;

  data = (GstCollectData *) list->data;

  GST_DEBUG ("found pad %s:%s at %p", GST_DEBUG_PAD_NAME (pad), data);

  /* clear the stuff we configured */
  gst_pad_set_chain_function (pad, NULL);
  gst_pad_set_event_function (pad, NULL);
  GST_OBJECT_LOCK (pad);
  gst_pad_set_element_private (pad, NULL);
  GST_OBJECT_UNLOCK (pad);

  /* backward compat, also remove from data if stopped, note that this function
   * can only be called when we are stopped because we don't take the LOCK to
   * protect the pads->data list. */
  if (!pads->started) {
    GSList *dlist;

    dlist = g_slist_find_custom (pads->data, pad, (GCompareFunc) find_pad);
    if (dlist) {
      GstCollectData *pdata = dlist->data;

      pads->data = g_slist_delete_link (pads->data, dlist);
      unref_data (pdata);
    }
  }
  /* remove from the pad list */
  pads->abidata.ABI.pad_list =
      g_slist_delete_link (pads->abidata.ABI.pad_list, list);
  pads->abidata.ABI.pad_cookie++;

  /* signal waiters because something changed */
  GST_COLLECT_PADS_BROADCAST (pads);

  /* deactivate the pad when needed */
  if (!pads->started)
    gst_pad_set_active (pad, FALSE);

  /* clean and free the collect data */
  unref_data (data);

  GST_COLLECT_PADS_PAD_UNLOCK (pads);

  return TRUE;

unknown_pad:
  {