Re: Fixing the Gst::Message classes

[José Alburquerque <jaalburquerque cox net>]

Murray Cumming wrote:
> On Wed, 2007-12-12 at 10:35 -0500, José Alburquerque wrote:
>   
> > Oops, my mistake.  I re-tested, modifying the ogg player version in
> > svn 
> > to use signals (attached as ogg-player-signal.cc) and it works.
> >     
>
> Help me out. What has changed in this example? How are you using signals
> in some new way?
>
>   
Here's the original.  AFAICT, the only change is in the error message 
parsing.  The e-mail I submitted in is: 
http://mail.gnome.org/archives/gtkmm-list/2007-December/msg00034.html  
Would this be a problem?

-Jose

#include <iostream>
#include <gstmm.h>

using namespace Glib;
using namespace Gst;
using namespace std;

void bus_message_received(const RefPtr<Message>& message,
RefPtr<MainLoop> mainLoop)
{
  switch (message->get_type()) {
    case MESSAGE_EOS:
      cout << "End of stream" << endl;
      mainLoop->quit();
      break;
    case MESSAGE_ERROR:
      cerr << "Error." << endl;
      mainLoop->quit();
      break;
    default:
      break;
  }
}

void parser_pad_added(const RefPtr<Pad>& newPad, RefPtr<Element> decoder)
{
  cout << "Dynamic pad created, linking parser/decoder." << endl;
  RefPtr<Pad> sinkPad = decoder->get_pad("sink");
  newPad->link(sinkPad);
}

int main(int argc, char* argv[]) {
  if (argc != 2) {
    cout << "Usage: " << argv[0] << " <Ogg/Vorbis filename>" << endl;
    return -1;
  }

  Gst::init(argc, argv);
  RefPtr<MainLoop> mainLoop = Glib::MainLoop::create();

  /* create elements */
  RefPtr<Pipeline> pipeline = Gst::Pipeline::create("audio-player");
  RefPtr<Element> source = Gst::Element::create("filesrc", "file-source");
  RefPtr<Element> parser = Gst::Element::create("oggdemux", "ogg-parser");
  RefPtr<Element> decoder = Gst::Element::create("vorbisdec", "vorbis-decoder");
  RefPtr<Element> conv = Gst::Element::create("audioconvert", "converter");
  RefPtr<Element> sink = Gst::Element::create("alsasink", "alsa-output");

  if (!pipeline || !source || !parser || !decoder || !conv || !sink) {
    cerr << "One element could not be created." << endl;
    return -1;
  }

  /* set filename property on the file source. Also add a message
   * handler. */
  source->set_property("location", (string) argv[1]);

  RefPtr<Bus> bus = pipeline->get_bus();
  bus->add_signal_watch();
  bus->signal_message().connect(sigc::bind< RefPtr<MainLoop> >(
    sigc::ptr_fun(&bus_message_received), mainLoop) );

  /* put all elements in a bin */
  pipeline->add(source)->add(parser)->add(decoder)->add(conv)->add(sink);

  /* link together - note that we cannot link the parser and
   * decoder yet, becuse the parser uses dynamic pads. For that,
   * we set a pad-added signal handler. */
  source->link(parser);
  decoder->link(conv)->link(sink);

  parser->signal_pad_added().connect(sigc::bind< RefPtr<Element> >(
    sigc::ptr_fun(&parser_pad_added), decoder) );

  /* Now set to playing and iterate. */
  cout << "Setting to PLAYING." << endl;
  pipeline->set_state(STATE_PLAYING);
  cout << "Running." << endl;
  mainLoop->run();

  /* clean up nicely */
  cout << "Returned, stopping playback." << endl;
  pipeline->set_state(STATE_NULL);

  bus->remove_signal_watch();

  return 0;
}