ocarina/gui/gst.cpp

/*
 * Copyright 2014 (c) Anna Schumaker.
 *
 * The gst_init() function parses command line options passed to Ocarina
 * through argv.  Use the command `gst-inspect-1.0 --help-gst` to find
 * what options are supported.
 */
#include <core/audio.h>
#include <gui/ocarina.h>
#include <gst/gst.h>


static GstBus      *gst_bus;
static GstElement  *gst_player;
static Gtk::Button *o_play;
static Gtk::Button *o_pause;


static bool gst_change_state(GstState state)
{
	GstStateChangeReturn ret = gst_element_set_state(gst_player, state);
	switch (ret) {
	case GST_STATE_CHANGE_SUCCESS:
	case GST_STATE_CHANGE_ASYNC:
		return true;
	default:
		return false;
	}
}


class GSTDriver : public AudioDriver
{
public:
	void load(Track *track)
	{
		gchar *uri = gst_filename_to_uri(track->path().c_str(), NULL);

		gst_change_state(GST_STATE_NULL);
		g_object_set(G_OBJECT(gst_player), "uri", uri, NULL);
		g_free(uri);

		on_track_loaded(track);
	}

	void play()
	{
		if (gst_change_state(GST_STATE_PLAYING)) {
			o_play->hide();
			o_pause->show();
		}
	}

	void pause()
	{
		if (gst_change_state(GST_STATE_PAUSED)) {
			o_play->show();
			o_pause->hide();
		}
	}

	bool is_playing()
	{
		GstState state;
		gst_element_get_state(gst_player,
				      &state,
				      NULL,
				      GST_CLOCK_TIME_NONE);
		return state == GST_STATE_PLAYING;
	}

	void seek_to(long offset)
	{
		gst_element_seek_simple(gst_player,
					GST_FORMAT_TIME,
					GST_SEEK_FLAG_FLUSH,
					offset);
	}

	long position()
	{
		long position;
		if (gst_element_query_position(gst_player,
					       GST_FORMAT_TIME,
					       &position))
			return position;
		return 0;
	}

	long duration()
	{
		long duration;
		if (gst_element_query_duration(gst_player,
					       GST_FORMAT_TIME,
					       &duration))
			return duration;
		return 0;
	}
};

static GSTDriver *gst_driver;


static void parse_gst_error(GstMessage *error)
{
	GError *err;
	Track  *track = audio :: current_track();

	gst_message_parse_error(error, &err, NULL);

	if (track)
		g_print("Error playing file: %s\n", track->path().c_str());
	g_print("Error: %s\n", err->message);
	g_error_free(err);
}

static gboolean on_gst_message(GstBus *bus, GstMessage *message, gpointer data)
{
	switch (GST_MESSAGE_TYPE(message)) {
	case GST_MESSAGE_ERROR:
		parse_gst_error(message);
		audio :: next();
		break;
	case GST_MESSAGE_EOS:
		gst_driver->eos();
		on_pause_count_changed(audio :: pause_enabled(),
				       audio :: pause_count());
		break;
	default:
		break;
	}

	return TRUE;
}


void init_gst(int *argc, char ***argv)
{
	gst_init(argc, argv);

	gst_player = gst_element_factory_make("playbin", "ocarina_player");
	gst_bus    = gst_pipeline_get_bus(GST_PIPELINE(gst_player));
	gst_driver = new GSTDriver();

	o_play  = lib :: get_widget<Gtk::Button>("o_play");
	o_pause = lib :: get_widget<Gtk::Button>("o_pause");

	gst_bus_add_watch(gst_bus, on_gst_message, NULL);
	o_play->signal_clicked().connect(sigc::ptr_fun(audio :: play));
	o_pause->signal_clicked().connect(sigc::ptr_fun(audio :: pause));
}

void quit_gst()
{
	delete gst_driver;
	gst_change_state(GST_STATE_NULL);
	gst_deinit();
}