gstreamer/gst/base/gstbasesrc.c

/* GStreamer
 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
 *               2000,2005 Wim Taymans <wim@fluendo.com>
 *
 * gstbasesrc.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.
 */


#include <stdlib.h>
#include <string.h>

#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif

#include "gstbasesrc.h"
#include <gst/gstmarshal.h>

#define DEFAULT_BLOCKSIZE	4096

GST_DEBUG_CATEGORY_STATIC (gst_basesrc_debug);
#define GST_CAT_DEFAULT gst_basesrc_debug

/* BaseSrc signals and args */
enum
{
  /* FILL ME */
  LAST_SIGNAL
};

enum
{
  ARG_0,
  ARG_BLOCKSIZE,
};

static GstElementClass *parent_class = NULL;

static void gst_basesrc_base_init (gpointer g_class);
static void gst_basesrc_class_init (GstBaseSrcClass * klass);
static void gst_basesrc_init (GstBaseSrc * src, gpointer g_class);

GType
gst_basesrc_get_type (void)
{
  static GType basesrc_type = 0;

  if (!basesrc_type) {
    static const GTypeInfo basesrc_info = {
      sizeof (GstBaseSrcClass),
      (GBaseInitFunc) gst_basesrc_base_init,
      NULL,
      (GClassInitFunc) gst_basesrc_class_init,
      NULL,
      NULL,
      sizeof (GstBaseSrc),
      0,
      (GInstanceInitFunc) gst_basesrc_init,
    };

    basesrc_type = g_type_register_static (GST_TYPE_ELEMENT,
        "GstBaseSrc", &basesrc_info, G_TYPE_FLAG_ABSTRACT);
  }
  return basesrc_type;
}

static gboolean gst_basesrc_activate (GstPad * pad, GstActivateMode mode);
static void gst_basesrc_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec);
static void gst_basesrc_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec);
static gboolean gst_basesrc_event_handler (GstPad * pad, GstEvent * event);
static const GstEventMask *gst_basesrc_get_event_mask (GstPad * pad);
static const GstQueryType *gst_basesrc_get_query_types (GstPad * pad);
static gboolean gst_basesrc_query (GstPad * pad, GstQueryType type,
    GstFormat * format, gint64 * value);
static const GstFormat *gst_basesrc_get_formats (GstPad * pad);

static gboolean gst_basesrc_unlock (GstBaseSrc * basesrc);
static gboolean gst_basesrc_get_size (GstBaseSrc * basesrc, guint64 * size);
static gboolean gst_basesrc_start (GstBaseSrc * basesrc);
static gboolean gst_basesrc_stop (GstBaseSrc * basesrc);

static GstElementStateReturn gst_basesrc_change_state (GstElement * element);

static void gst_basesrc_loop (GstPad * pad);
static gboolean gst_basesrc_check_get_range (GstPad * pad);
static GstFlowReturn gst_basesrc_get_range (GstPad * pad, guint64 offset,
    guint length, GstBuffer ** buf);

static GstCaps *gst_basesrc_type_find (GstBaseSrc * src);

static void
gst_basesrc_base_init (gpointer g_class)
{
  GST_DEBUG_CATEGORY_INIT (gst_basesrc_debug, "basesrc", 0, "basesrc element");
}

static void
gst_basesrc_class_init (GstBaseSrcClass * klass)
{
  GObjectClass *gobject_class;
  GstElementClass *gstelement_class;

  gobject_class = (GObjectClass *) klass;
  gstelement_class = (GstElementClass *) klass;

  parent_class = g_type_class_ref (GST_TYPE_ELEMENT);

  gobject_class->set_property = GST_DEBUG_FUNCPTR (gst_basesrc_set_property);
  gobject_class->get_property = GST_DEBUG_FUNCPTR (gst_basesrc_get_property);

  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_BLOCKSIZE,
      g_param_spec_ulong ("blocksize", "Block size",
          "Size in bytes to read per buffer", 1, G_MAXULONG, DEFAULT_BLOCKSIZE,
          G_PARAM_READWRITE));

  gstelement_class->change_state = GST_DEBUG_FUNCPTR (gst_basesrc_change_state);
}

static void
gst_basesrc_init (GstBaseSrc * basesrc, gpointer g_class)
{
  GstPad *pad;
  GstPadTemplate *pad_template;

  pad_template =
      gst_element_class_get_pad_template (GST_ELEMENT_CLASS (g_class), "src");
  g_return_if_fail (pad_template != NULL);

  pad = gst_pad_new_from_template (pad_template, "src");

  gst_pad_set_activate_function (pad, gst_basesrc_activate);
  gst_pad_set_event_function (pad, gst_basesrc_event_handler);
  gst_pad_set_event_mask_function (pad, gst_basesrc_get_event_mask);
  gst_pad_set_query_function (pad, gst_basesrc_query);
  gst_pad_set_query_type_function (pad, gst_basesrc_get_query_types);
  gst_pad_set_formats_function (pad, gst_basesrc_get_formats);
  gst_pad_set_loop_function (pad, gst_basesrc_loop);
  gst_pad_set_checkgetrange_function (pad, gst_basesrc_check_get_range);
  gst_pad_set_getrange_function (pad, gst_basesrc_get_range);
  /* hold ref to pad */
  basesrc->srcpad = pad;
  gst_element_add_pad (GST_ELEMENT (basesrc), pad);

  basesrc->segment_start = -1;
  basesrc->segment_end = -1;
  basesrc->blocksize = DEFAULT_BLOCKSIZE;

  GST_FLAG_UNSET (basesrc, GST_BASESRC_STARTED);
}

static const GstFormat *
gst_basesrc_get_formats (GstPad * pad)
{
  static const GstFormat formats[] = {
    GST_FORMAT_DEFAULT,
    GST_FORMAT_BYTES,
    0,
  };

  return formats;
}

static const GstQueryType *
gst_basesrc_get_query_types (GstPad * pad)
{
  static const GstQueryType types[] = {
    GST_QUERY_TOTAL,
    GST_QUERY_POSITION,
    GST_QUERY_START,
    GST_QUERY_SEGMENT_END,
    0,
  };

  return types;
}

static gboolean
gst_basesrc_query (GstPad * pad, GstQueryType type,
    GstFormat * format, gint64 * value)
{
  GstBaseSrc *src = GST_BASESRC (GST_PAD_PARENT (pad));

  if (*format == GST_FORMAT_DEFAULT)
    *format = GST_FORMAT_BYTES;

  switch (type) {
    case GST_QUERY_TOTAL:
      switch (*format) {
        case GST_FORMAT_BYTES:
        {
          gboolean ret;

          ret = gst_basesrc_get_size (src, value);
          GST_DEBUG ("getting length %d %lld", ret, *value);
          return ret;
        }
        case GST_FORMAT_PERCENT:
          *value = GST_FORMAT_PERCENT_MAX;
          return TRUE;
        default:
          return FALSE;
      }
      break;
    case GST_QUERY_POSITION:
      switch (*format) {
        case GST_FORMAT_BYTES:
          *value = src->offset;
          break;
        case GST_FORMAT_PERCENT:
          if (!gst_basesrc_get_size (src, value))
            return FALSE;
          *value = src->offset * GST_FORMAT_PERCENT_MAX / *value;
          return TRUE;
        default:
          return FALSE;
      }
      break;
    case GST_QUERY_START:
      *value = src->segment_start;
      return TRUE;
    case GST_QUERY_SEGMENT_END:
      *value = src->segment_end;
      return TRUE;
    default:
      return FALSE;
  }
  return FALSE;
}

static const GstEventMask *
gst_basesrc_get_event_mask (GstPad * pad)
{
  static const GstEventMask masks[] = {
    {GST_EVENT_SEEK, GST_SEEK_METHOD_CUR | GST_SEEK_METHOD_SET |
          GST_SEEK_METHOD_END | GST_SEEK_FLAG_FLUSH |
          GST_SEEK_FLAG_SEGMENT_LOOP},
    {GST_EVENT_FLUSH, 0},
    {GST_EVENT_SIZE, 0},
    {0, 0},
  };
  return masks;
}

static gboolean
gst_basesrc_do_seek (GstBaseSrc * src, GstEvent * event)
{
  GstFormat format;
  gint64 offset;

  format = GST_EVENT_SEEK_FORMAT (event);

  /* get seek format */
  if (format == GST_FORMAT_DEFAULT)
    format = GST_FORMAT_BYTES;
  /* we can only seek bytes */
  if (format != GST_FORMAT_BYTES)
    return FALSE;

  /* get seek positions */
  offset = GST_EVENT_SEEK_OFFSET (event);
  src->segment_start = offset;
  src->segment_end = GST_EVENT_SEEK_ENDOFFSET (event);
  src->segment_loop = GST_EVENT_SEEK_FLAGS (event) & GST_SEEK_FLAG_SEGMENT_LOOP;

  /* send flush start */
  gst_pad_push_event (src->srcpad, gst_event_new_flush (FALSE));

  /* unblock streaming thread */
  gst_basesrc_unlock (src);

  /* grab streaming lock */
  GST_STREAM_LOCK (src->srcpad);

  switch (GST_EVENT_SEEK_METHOD (event)) {
    case GST_SEEK_METHOD_SET:
      if (offset < 0)
        goto error;
      src->offset = MIN (offset, src->size);
      GST_DEBUG_OBJECT (src, "seek set pending to %" G_GINT64_FORMAT,
          src->offset);
      break;
    case GST_SEEK_METHOD_CUR:
      offset += src->offset;
      src->offset = CLAMP (offset, 0, src->size);
      GST_DEBUG_OBJECT (src, "seek cur pending to %" G_GINT64_FORMAT,
          src->offset);
      break;
    case GST_SEEK_METHOD_END:
      if (offset > 0)
        goto error;
      offset = src->size + offset;
      src->offset = MAX (0, offset);
      GST_DEBUG_OBJECT (src, "seek end pending to %" G_GINT64_FORMAT,
          src->offset);
      break;
    default:
      goto error;
  }
  /* send flush end */
  gst_pad_push_event (src->srcpad, gst_event_new_flush (TRUE));

  /* now send discont */
  {
    GstEvent *event;

    event = gst_event_new_discontinuous (1.0,
        GST_FORMAT_TIME,
        (gint64) src->segment_start, (gint64) src->segment_end, NULL);

    gst_pad_push_event (src->srcpad, event);
  }

  /* and restart the task */
  if (GST_RPAD_TASK (src->srcpad)) {
    gst_task_start (GST_RPAD_TASK (src->srcpad));
  }
  GST_STREAM_UNLOCK (src->srcpad);

  gst_event_unref (event);

  return TRUE;

  /* ERROR */
error:
  {
    GST_DEBUG_OBJECT (src, "seek error");
    GST_STREAM_UNLOCK (src->srcpad);
    gst_event_unref (event);
    return FALSE;
  }
}

static gboolean
gst_basesrc_event_handler (GstPad * pad, GstEvent * event)
{
  GstBaseSrc *src;

  src = GST_BASESRC (GST_PAD_PARENT (pad));

  switch (GST_EVENT_TYPE (event)) {
    case GST_EVENT_SEEK:
      return gst_basesrc_do_seek (src, event);
    case GST_EVENT_SIZE:
    {
      GstFormat format;

      format = GST_EVENT_SIZE_FORMAT (event);
      if (format == GST_FORMAT_DEFAULT)
        format = GST_FORMAT_BYTES;
      /* we can only accept bytes */
      if (format != GST_FORMAT_BYTES)
        return FALSE;

      src->blocksize = GST_EVENT_SIZE_VALUE (event);
      g_object_notify (G_OBJECT (src), "blocksize");
      break;
    }
    case GST_EVENT_FLUSH:
      /* cancel any blocking getrange */
      if (!GST_EVENT_FLUSH_DONE (event))
        gst_basesrc_unlock (src);
      break;
    default:
      break;
  }
  gst_event_unref (event);

  return TRUE;
}

static void
gst_basesrc_set_property (GObject * object, guint prop_id, const GValue * value,
    GParamSpec * pspec)
{
  GstBaseSrc *src;

  src = GST_BASESRC (object);

  switch (prop_id) {
    case ARG_BLOCKSIZE:
      src->blocksize = g_value_get_int (value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_basesrc_get_property (GObject * object, guint prop_id, GValue * value,
    GParamSpec * pspec)
{
  GstBaseSrc *src;

  src = GST_BASESRC (object);

  switch (prop_id) {
    case ARG_BLOCKSIZE:
      g_value_set_int (value, src->blocksize);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static GstFlowReturn
gst_basesrc_get_range_unlocked (GstPad * pad, guint64 offset, guint length,
    GstBuffer ** buf)
{
  GstFlowReturn ret;
  GstBaseSrc *src;
  GstBaseSrcClass *bclass;

  src = GST_BASESRC (GST_OBJECT_PARENT (pad));
  bclass = GST_BASESRC_GET_CLASS (src);

  if (!GST_FLAG_IS_SET (src, GST_BASESRC_STARTED))
    goto not_started;

  if (!bclass->create)
    goto no_function;

  /* check size */
  if (src->size != -1) {
    if (offset + length > src->size) {
      if (bclass->get_size)
        bclass->get_size (src, &src->size);

      if (offset + length > src->size) {
        length = src->size - offset;
      }
    }
  }
  if (length == 0)
    return GST_FLOW_UNEXPECTED;

  ret = bclass->create (src, offset, length, buf);

  return ret;

  /* ERROR */
not_started:
  {
    GST_DEBUG_OBJECT (src, "getrange but not started");
    return GST_FLOW_WRONG_STATE;
  }
no_function:
  {
    GST_DEBUG_OBJECT (src, "no create function");
    return GST_FLOW_ERROR;
  }
}

static GstFlowReturn
gst_basesrc_get_range (GstPad * pad, guint64 offset, guint length,
    GstBuffer ** ret)
{
  GstFlowReturn fret;

  GST_STREAM_LOCK (pad);

  fret = gst_basesrc_get_range_unlocked (pad, offset, length, ret);

  GST_STREAM_UNLOCK (pad);

  return fret;
}

static gboolean
gst_basesrc_check_get_range (GstPad * pad)
{
  GstBaseSrc *src;

  src = GST_BASESRC (GST_OBJECT_PARENT (pad));

  if (!GST_FLAG_IS_SET (src, GST_BASESRC_STARTED)) {
    gst_basesrc_start (src);
    gst_basesrc_stop (src);
  }

  return src->seekable;
}

static void
gst_basesrc_loop (GstPad * pad)
{
  GstBaseSrc *src;
  GstBuffer *buf = NULL;
  GstFlowReturn ret;

  src = GST_BASESRC (GST_OBJECT_PARENT (pad));

  GST_STREAM_LOCK (pad);

  ret = gst_basesrc_get_range_unlocked (pad, src->offset, src->blocksize, &buf);
  if (ret != GST_FLOW_OK)
    goto eos;

  src->offset += GST_BUFFER_SIZE (buf);

  ret = gst_pad_push (pad, buf);
  if (ret != GST_FLOW_OK)
    goto pause;

  GST_STREAM_UNLOCK (pad);
  return;

eos:
  {
    GST_DEBUG_OBJECT (src, "going to EOS");
    gst_task_pause (GST_RPAD_TASK (pad));
    gst_pad_push_event (pad, gst_event_new (GST_EVENT_EOS));
    GST_STREAM_UNLOCK (pad);
    return;
  }
pause:
  {
    GST_DEBUG_OBJECT (src, "pausing task");
    gst_task_pause (GST_RPAD_TASK (pad));
    GST_STREAM_UNLOCK (pad);
    return;
  }
}

static gboolean
gst_basesrc_unlock (GstBaseSrc * basesrc)
{
  GstBaseSrcClass *bclass;
  gboolean result = FALSE;

  bclass = GST_BASESRC_GET_CLASS (basesrc);
  if (bclass->unlock)
    result = bclass->unlock (basesrc);

  return result;
}

static gboolean
gst_basesrc_get_size (GstBaseSrc * basesrc, guint64 * size)
{
  GstBaseSrcClass *bclass;
  gboolean result = FALSE;

  bclass = GST_BASESRC_GET_CLASS (basesrc);
  if (bclass->get_size)
    result = bclass->get_size (basesrc, size);

  if (result)
    basesrc->size = *size;

  return result;
}

static gboolean
gst_basesrc_start (GstBaseSrc * basesrc)
{
  GstBaseSrcClass *bclass;
  gboolean result;

  if (GST_FLAG_IS_SET (basesrc, GST_BASESRC_STARTED))
    return TRUE;

  bclass = GST_BASESRC_GET_CLASS (basesrc);
  if (bclass->start)
    result = bclass->start (basesrc);
  else
    result = TRUE;

  if (!result)
    goto could_not_start;

  GST_FLAG_SET (basesrc, GST_BASESRC_STARTED);

  /* start in the beginning */
  basesrc->offset = 0;
  basesrc->segment_start = 0;

  /* figure out the size */
  if (bclass->get_size)
    result = bclass->get_size (basesrc, &basesrc->size);
  else
    result = FALSE;

  GST_DEBUG ("size %lld", basesrc->size);

  /* we always run to the end */
  basesrc->segment_end = -1;

  /* check if we can seek */
  if (bclass->is_seekable)
    basesrc->seekable = bclass->is_seekable (basesrc);
  else
    basesrc->seekable = FALSE;

  /* run typefind */
  if (basesrc->seekable) {
    GstCaps *caps;

    caps = gst_basesrc_type_find (basesrc);
    gst_pad_set_caps (basesrc->srcpad, caps);
  }
  return TRUE;

  /* ERROR */
could_not_start:
  {
    GST_DEBUG_OBJECT (basesrc, "could not start");
    return FALSE;
  }
}

static gboolean
gst_basesrc_stop (GstBaseSrc * basesrc)
{
  GstBaseSrcClass *bclass;
  gboolean result = TRUE;

  if (!GST_FLAG_IS_SET (basesrc, GST_BASESRC_STARTED))
    return TRUE;

  bclass = GST_BASESRC_GET_CLASS (basesrc);
  if (bclass->stop)
    result = bclass->stop (basesrc);

  if (result)
    GST_FLAG_UNSET (basesrc, GST_BASESRC_STARTED);

  return result;
}

static gboolean
gst_basesrc_activate (GstPad * pad, GstActivateMode mode)
{
  gboolean result;
  GstBaseSrc *basesrc;

  basesrc = GST_BASESRC (GST_OBJECT_PARENT (pad));

  /* prepare subclass first */
  switch (mode) {
    case GST_ACTIVATE_PUSH:
    case GST_ACTIVATE_PULL:
      result = gst_basesrc_start (basesrc);
      break;
    default:
      result = TRUE;
      break;
  }
  /* if that failed we can stop here */
  if (!result)
    goto error_start;

  result = FALSE;
  switch (mode) {
    case GST_ACTIVATE_PUSH:
      /* if we have a scheduler we can start the task */
      if (GST_ELEMENT_SCHEDULER (basesrc)) {
        GST_STREAM_LOCK (pad);
        GST_RPAD_TASK (pad) =
            gst_scheduler_create_task (GST_ELEMENT_SCHEDULER (basesrc),
            (GstTaskFunction) gst_basesrc_loop, pad);

        gst_task_start (GST_RPAD_TASK (pad));
        GST_STREAM_UNLOCK (pad);
        result = TRUE;
      }
      break;
    case GST_ACTIVATE_PULL:
      result = TRUE;
      break;
    case GST_ACTIVATE_NONE:
      /* step 1, unblock clock sync (if any) */

      /* step 2, make sure streaming finishes */
      GST_STREAM_LOCK (pad);
      /* step 3, stop the task */
      if (GST_RPAD_TASK (pad)) {
        gst_task_stop (GST_RPAD_TASK (pad));
        gst_object_unref (GST_OBJECT (GST_RPAD_TASK (pad)));
        GST_RPAD_TASK (pad) = NULL;
      }
      GST_STREAM_UNLOCK (pad);

      result = TRUE;
      break;
  }
  return result;

  /* ERROR */
error_start:
  {
    GST_DEBUG_OBJECT (basesrc, "failed to start");
    return FALSE;
  }
}

static GstElementStateReturn
gst_basesrc_change_state (GstElement * element)
{
  GstBaseSrc *basesrc;
  GstElementStateReturn result = GST_STATE_FAILURE;
  GstElementState transition;

  basesrc = GST_BASESRC (element);

  transition = GST_STATE_TRANSITION (element);

  switch (transition) {
    case GST_STATE_NULL_TO_READY:
      break;
    case GST_STATE_READY_TO_PAUSED:
      break;
    case GST_STATE_PAUSED_TO_PLAYING:
      break;
    default:
      break;
  }

  result = GST_ELEMENT_CLASS (parent_class)->change_state (element);

  switch (transition) {
    case GST_STATE_PLAYING_TO_PAUSED:
      break;
    case GST_STATE_PAUSED_TO_READY:
      result = gst_basesrc_stop (basesrc);
      break;
    case GST_STATE_READY_TO_NULL:
      break;
    default:
      break;
  }

  return result;
}

/**
 * typefind code here
 */
typedef struct
{
  GstBaseSrc *src;
  guint best_probability;
  GstCaps *caps;

  GstBuffer *buffer;
}
BaseSrcTypeFind;

static guint8 *
basesrc_find_peek (gpointer data, gint64 offset, guint size)
{
  BaseSrcTypeFind *find;
  GstBuffer *buffer;
  GstBaseSrc *src;
  GstFlowReturn ret;

  if (size == 0)
    return NULL;

  find = (BaseSrcTypeFind *) data;
  src = find->src;

  if (offset < 0) {
    offset += src->size;
  }

  buffer = NULL;
  ret = gst_basesrc_get_range_unlocked (src->srcpad, offset, size, &buffer);

  if (find->buffer) {
    gst_buffer_unref (find->buffer);
    find->buffer = NULL;
  }

  if (ret != GST_FLOW_OK)
    goto error;

  find->buffer = buffer;

  return GST_BUFFER_DATA (buffer);

error:
  {
    return NULL;
  }
}

static void
basesrc_find_suggest (gpointer data, guint probability, const GstCaps * caps)
{
  BaseSrcTypeFind *find = (BaseSrcTypeFind *) data;

  if (probability > find->best_probability) {
    gst_caps_replace (&find->caps, gst_caps_copy (caps));
    find->best_probability = probability;
  }
}

static GstCaps *
gst_basesrc_type_find (GstBaseSrc * src)
{
  GstTypeFind gst_find;
  BaseSrcTypeFind find;
  GList *walk, *type_list = NULL;
  GstCaps *result = NULL;

  walk = type_list = gst_type_find_factory_get_list ();

  find.src = src;
  find.best_probability = 0;
  find.caps = NULL;
  find.buffer = NULL;
  gst_find.data = &find;
  gst_find.peek = basesrc_find_peek;
  gst_find.suggest = basesrc_find_suggest;
  gst_find.get_length = NULL;

  while (walk) {
    GstTypeFindFactory *factory = GST_TYPE_FIND_FACTORY (walk->data);

    gst_type_find_factory_call_function (factory, &gst_find);
    if (find.best_probability >= GST_TYPE_FIND_MAXIMUM)
      break;
    walk = g_list_next (walk);
  }

  if (find.best_probability > 0)
    result = find.caps;

  return result;
}