Initial MPRIS support

Implement a working MPRIS DBus connection with a separate API to control it. Right now only player playback state is reflected and Play/Pause/PlayPause calls work.

.gitattributes

@@ -1,4 +1,5 @@
 extras/**/* linguist-vendored
 lib/**/* linguist-vendored
 lib/**/**/* linguist-vendored
+lib/gst/clapper/gstclapper-mpris* linguist-vendored=false
 lib/gst/clapper/gtk4/* linguist-vendored=false

data/gstclapper-mpris-gdbus.xml

@@ -0,0 +1,52 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<node>
+  <interface name="org.mpris.MediaPlayer2">
+    <method name="Raise"/>
+    <method name="Quit"/>
+    <property name="CanQuit" type="b" access="read"/>
+    <property name="Fullscreen" type="b" access="readwrite"/>
+    <property name="CanSetFullscreen" type="b" access="read"/>
+    <property name="CanRaise" type="b" access="read"/>
+    <property name="HasTrackList" type="b" access="read"/>
+    <property name="Identity" type="s" access="read"/>
+    <property name="DesktopEntry" type="s" access="read"/>
+    <property name="SupportedUriSchemes" type="as" access="read"/>
+    <property name="SupportedMimeTypes" type="as" access="read"/>
+  </interface>
+  <interface name="org.mpris.MediaPlayer2.Player">
+    <method name="Next"/>
+    <method name="Previous"/>
+    <method name="Pause"/>
+    <method name="PlayPause"/>
+    <method name="Stop"/>
+    <method name="Play"/>
+    <method name="Seek">
+      <arg name="Offset" type="x" direction="in"/>
+    </method>
+    <method name="SetPosition">
+      <arg name="TrackId" type="o" direction="in"/>
+      <arg name="Position" type="x" direction="in"/>
+    </method>
+    <method name="OpenUri">
+      <arg name="Uri" type="s" direction="in"/>
+    </method>
+    <signal name="Seeked">
+      <arg type="x" name="Position"/>
+    </signal>
+    <property name="PlaybackStatus" type="s" access="read"/>
+    <property name="LoopStatus" type="s" access="readwrite"/>
+    <property name="Rate" type="d" access="readwrite"/>
+    <property name="Shuffle" type="b" access="readwrite"/>
+    <property name="Metadata" type="a{sv}" access="read"/>
+    <property name="Volume" type="d" access="readwrite"/>
+    <property name="Position" type="x" access="read"/>
+    <property name="MinimumRate" type="d" access="read"/>
+    <property name="MaximumRate" type="d" access="read"/>
+    <property name="CanGoNext" type="b" access="read"/>
+    <property name="CanGoPrevious" type="b" access="read"/>
+    <property name="CanPlay" type="b" access="read"/>
+    <property name="CanPause" type="b" access="read"/>
+    <property name="CanSeek" type="b" access="read"/>
+    <property name="CanControl" type="b" access="read"/>
+  </interface>
+</node>

lib/gst/clapper/clapper.h

@@ -28,6 +28,7 @@
 #include <gst/clapper/gstclapper-g-main-context-signal-dispatcher.h>
 #include <gst/clapper/gstclapper-video-overlay-video-renderer.h>
 #include <gst/clapper/gstclapper-visualization.h>
+#include <gst/clapper/gstclapper-mpris.h>
 #include <gst/clapper/gstclapper-gtk4-plugin.h>
 
 #endif /* __CLAPPER_H__ */

lib/gst/clapper/gstclapper-mpris-private.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2021 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * 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., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __GST_CLAPPER_MPRIS_PRIVATE_H__
+#define __GST_CLAPPER_MPRIS_PRIVATE_H__
+
+#include <gst/clapper/gstclapper-mpris.h>
+#include <gst/clapper/gstclapper.h>
+
+G_BEGIN_DECLS
+
+G_GNUC_INTERNAL
+void gst_clapper_mpris_set_clapper                  (GstClapperMpris *self, GstClapper *clapper);
+
+G_GNUC_INTERNAL
+void gst_clapper_mpris_set_playback_status          (GstClapperMpris *self, const gchar *status);
+
+G_END_DECLS
+
+#endif /* __GST_CLAPPER_MPRIS_PRIVATE_H__ */

lib/gst/clapper/gstclapper-mpris.c

@@ -0,0 +1,530 @@
+/*
+ * Copyright (C) 2021 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * 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., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "gstclapper-mpris-gdbus.h"
+#include "gstclapper-mpris.h"
+#include "gstclapper-mpris-private.h"
+
+enum
+{
+  PROP_0,
+  PROP_OWN_NAME,
+  PROP_ID_PATH,
+  PROP_IDENTITY,
+  PROP_DESKTOP_ENTRY,
+  PROP_DEFAULT_ART_URL,
+  PROP_LAST
+};
+
+struct _GstClapperMpris
+{
+  GObject parent;
+
+  GstClapperMprisMediaPlayer2 *base_skeleton;
+  GstClapperMprisMediaPlayer2Player *player_skeleton;
+
+  guint name_id;
+
+  /* Properties */
+  gchar *own_name;
+  gchar *id_path;
+  gchar *identity;
+  gchar *desktop_entry;
+  gchar *default_art_url;
+
+  /* Current status */
+  gchar *playback_status;
+  gboolean can_play;
+
+  GThread *thread;
+  GMutex lock;
+  GCond cond;
+  GMainContext *context;
+  GMainLoop *loop;
+};
+
+struct _GstClapperMprisClass
+{
+  GObjectClass parent_class;
+};
+
+GST_DEBUG_CATEGORY_STATIC (gst_clapper_mpris_debug);
+#define GST_CAT_DEFAULT gst_clapper_mpris_debug
+
+#define parent_class gst_clapper_mpris_parent_class
+G_DEFINE_TYPE (GstClapperMpris, gst_clapper_mpris, G_TYPE_OBJECT);
+
+static GParamSpec *param_specs[PROP_LAST] = { NULL, };
+
+static void gst_clapper_mpris_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec);
+static void gst_clapper_mpris_dispose (GObject * object);
+static void gst_clapper_mpris_finalize (GObject * object);
+static void gst_clapper_mpris_constructed (GObject * object);
+static gpointer gst_clapper_mpris_main (gpointer data);
+
+static void unregister (GstClapperMpris * self);
+
+static void
+gst_clapper_mpris_init (GstClapperMpris * self)
+{
+  GST_DEBUG_CATEGORY_INIT (gst_clapper_mpris_debug, "ClapperMpris", 0,
+      "GstClapperMpris");
+  GST_TRACE_OBJECT (self, "Initializing");
+
+  self = gst_clapper_mpris_get_instance_private (self);
+
+  g_mutex_init (&self->lock);
+  g_cond_init (&self->cond);
+
+  self->context = g_main_context_new ();
+  self->loop = g_main_loop_new (self->context, FALSE);
+
+  self->base_skeleton = gst_clapper_mpris_media_player2_skeleton_new ();
+  self->player_skeleton = gst_clapper_mpris_media_player2_player_skeleton_new ();
+
+  self->name_id = 0;
+  self->own_name = NULL;
+  self->id_path = NULL;
+  self->identity = NULL;
+  self->desktop_entry = NULL;
+  self->default_art_url = NULL;
+
+  self->playback_status = g_strdup ("Stopped");
+
+  GST_TRACE_OBJECT (self, "Initialized");
+}
+
+static void
+gst_clapper_mpris_class_init (GstClapperMprisClass * klass)
+{
+  GObjectClass *gobject_class = (GObjectClass *) klass;
+
+  gobject_class->set_property = gst_clapper_mpris_set_property;
+  gobject_class->dispose = gst_clapper_mpris_dispose;
+  gobject_class->finalize = gst_clapper_mpris_finalize;
+  gobject_class->constructed = gst_clapper_mpris_constructed;
+
+  param_specs[PROP_OWN_NAME] =
+      g_param_spec_string ("own-name", "DBus own name",
+      "DBus name to own on connection",
+      NULL, G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY |
+      G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  param_specs[PROP_ID_PATH] =
+      g_param_spec_string ("id-path", "DBus id path",
+      "A valid D-Bus path describing this player",
+      NULL, G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY |
+      G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  param_specs[PROP_IDENTITY] =
+      g_param_spec_string ("identity", "Player name",
+      "A friendly name to identify the media player",
+      NULL, G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY |
+      G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  param_specs[PROP_DESKTOP_ENTRY] =
+      g_param_spec_string ("desktop-entry", "Desktop entry filename",
+      "The basename of an installed .desktop file",
+      NULL, G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY |
+      G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  param_specs[PROP_DEFAULT_ART_URL] =
+      g_param_spec_string ("default-art-url", "Default Art URL",
+      "Default art to show when media does not provide one",
+      NULL, G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY |
+      G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  g_object_class_install_properties (gobject_class, PROP_LAST, param_specs);
+}
+
+static void
+gst_clapper_mpris_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstClapperMpris *self = GST_CLAPPER_MPRIS (object);
+
+  switch (prop_id) {
+    case PROP_OWN_NAME:
+      self->own_name = g_value_dup_string (value);
+      break;
+    case PROP_ID_PATH:
+      self->id_path = g_value_dup_string (value);
+      break;
+    case PROP_IDENTITY:
+      self->identity = g_value_dup_string (value);
+      break;
+    case PROP_DESKTOP_ENTRY:
+      self->desktop_entry = g_value_dup_string (value);
+      break;
+    case PROP_DEFAULT_ART_URL:
+      self->default_art_url = g_value_dup_string (value);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_clapper_mpris_dispose (GObject * object)
+{
+  GstClapperMpris *self = GST_CLAPPER_MPRIS (object);
+
+  GST_TRACE_OBJECT (self, "Stopping main thread");
+
+  if (self->loop) {
+    g_main_loop_quit (self->loop);
+
+    if (self->thread != g_thread_self ())
+      g_thread_join (self->thread);
+    else
+      g_thread_unref (self->thread);
+    self->thread = NULL;
+
+    g_main_loop_unref (self->loop);
+    self->loop = NULL;
+
+    g_main_context_unref (self->context);
+    self->context = NULL;
+  }
+
+  G_OBJECT_CLASS (parent_class)->dispose (object);
+}
+
+static void
+gst_clapper_mpris_finalize (GObject * object)
+{
+  GstClapperMpris *self = GST_CLAPPER_MPRIS (object);
+
+  GST_TRACE_OBJECT (self, "Finalize");
+
+  g_free (self->own_name);
+  g_free (self->id_path);
+  g_free (self->identity);
+  g_free (self->desktop_entry);
+  g_free (self->default_art_url);
+  g_free (self->playback_status);
+
+  if (self->base_skeleton)
+    g_object_unref (self->base_skeleton);
+  if (self->player_skeleton)
+    g_object_unref (self->player_skeleton);
+
+  g_mutex_clear (&self->lock);
+  g_cond_clear (&self->cond);
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static void
+gst_clapper_mpris_constructed (GObject * object)
+{
+  GstClapperMpris *self = GST_CLAPPER_MPRIS (object);
+
+  GST_TRACE_OBJECT (self, "Constructed");
+
+  g_mutex_lock (&self->lock);
+  self->thread = g_thread_new ("GstClapperMpris",
+      gst_clapper_mpris_main, self);
+  while (!self->loop || !g_main_loop_is_running (self->loop))
+    g_cond_wait (&self->cond, &self->lock);
+  g_mutex_unlock (&self->lock);
+
+  G_OBJECT_CLASS (parent_class)->constructed (object);
+}
+
+static gboolean
+main_loop_running_cb (gpointer user_data)
+{
+  GstClapperMpris *self = GST_CLAPPER_MPRIS (user_data);
+
+  GST_TRACE_OBJECT (self, "Main loop running now");
+
+  g_mutex_lock (&self->lock);
+  g_cond_signal (&self->cond);
+  g_mutex_unlock (&self->lock);
+
+  return G_SOURCE_REMOVE;
+}
+
+static gboolean
+handle_play_cb (GstClapperMprisMediaPlayer2Player * player_skeleton,
+    GDBusMethodInvocation * invocation, gpointer user_data)
+{
+  GstClapper *clapper = GST_CLAPPER (user_data);
+
+  gst_clapper_play (clapper);
+  gst_clapper_mpris_media_player2_player_complete_play (player_skeleton, invocation);
+
+  return TRUE;
+}
+
+static gboolean
+handle_pause_cb (GstClapperMprisMediaPlayer2Player * player_skeleton,
+    GDBusMethodInvocation * invocation, gpointer user_data)
+{
+  GstClapper *clapper = GST_CLAPPER (user_data);
+
+  gst_clapper_pause (clapper);
+  gst_clapper_mpris_media_player2_player_complete_pause (player_skeleton, invocation);
+
+  return TRUE;
+}
+
+static gboolean
+handle_play_pause_cb (GstClapperMprisMediaPlayer2Player * player_skeleton,
+    GDBusMethodInvocation * invocation, gpointer user_data)
+{
+  GstClapper *clapper = GST_CLAPPER (user_data);
+
+  gst_clapper_toggle_play (clapper);
+  gst_clapper_mpris_media_player2_player_complete_play_pause (player_skeleton, invocation);
+
+  return TRUE;
+}
+
+static void
+unregister (GstClapperMpris * self)
+{
+  if (!self->name_id)
+    return;
+
+  GST_DEBUG_OBJECT (self, "Unregister");
+  g_dbus_interface_skeleton_unexport (G_DBUS_INTERFACE_SKELETON (self->base_skeleton));
+  g_dbus_interface_skeleton_unexport (G_DBUS_INTERFACE_SKELETON (self->player_skeleton));
+  g_bus_unown_name (self->name_id);
+  self->name_id = 0;
+}
+
+static const gchar *
+_get_mpris_trackid (GstClapperMpris * self)
+{
+  /* TODO: Support more tracks */
+  return g_strdup_printf ("%s%s%i", self->id_path, "/Track/", 0);
+}
+
+static void
+name_acquired_cb (GDBusConnection * connection,
+    const gchar *name, gpointer user_data)
+{
+  GstClapperMpris *self = GST_CLAPPER_MPRIS (user_data);
+  GVariantBuilder builder;
+
+  g_dbus_interface_skeleton_export (G_DBUS_INTERFACE_SKELETON (self->base_skeleton),
+      connection, "/org/mpris/MediaPlayer2", NULL);
+  g_dbus_interface_skeleton_export (G_DBUS_INTERFACE_SKELETON (self->player_skeleton),
+      connection, "/org/mpris/MediaPlayer2", NULL);
+
+  if (self->identity)
+    gst_clapper_mpris_media_player2_set_identity (self->base_skeleton, self->identity);
+  if (self->desktop_entry)
+    gst_clapper_mpris_media_player2_set_desktop_entry (self->base_skeleton, self->desktop_entry);
+
+  gst_clapper_mpris_media_player2_player_set_playback_status (self->player_skeleton, "Stopped");
+  gst_clapper_mpris_media_player2_player_set_minimum_rate (self->player_skeleton, 0.01);
+  gst_clapper_mpris_media_player2_player_set_maximum_rate (self->player_skeleton, 2.0);
+  gst_clapper_mpris_media_player2_player_set_can_control (self->player_skeleton, TRUE);
+
+  g_object_bind_property (self->player_skeleton, "can-play",
+      self->player_skeleton, "can-pause", G_BINDING_DEFAULT);
+
+  g_variant_builder_init (&builder, G_VARIANT_TYPE_ARRAY);
+  g_variant_builder_add (&builder, "{sv}", "mpris:trackid", g_variant_new_string (_get_mpris_trackid (self)));
+  g_variant_builder_add (&builder, "{sv}", "mpris:length", g_variant_new_uint64 (0));
+  if (self->default_art_url)
+    g_variant_builder_add (&builder, "{sv}", "mpris:artUrl", g_variant_new_string (self->default_art_url));
+  gst_clapper_mpris_media_player2_player_set_metadata (self->player_skeleton, g_variant_builder_end (&builder));
+
+  GST_DEBUG_OBJECT (self, "Ready");
+}
+
+static void
+name_lost_cb (GDBusConnection * connection,
+    const gchar * name, gpointer user_data)
+{
+  GstClapperMpris *self = GST_CLAPPER_MPRIS (user_data);
+
+  unregister (self);
+}
+
+static gboolean
+mpris_update_props_dispatch (gpointer user_data)
+{
+  GstClapperMpris *self = GST_CLAPPER_MPRIS (user_data);
+
+  GST_DEBUG_OBJECT (self, "Updating MPRIS props");
+  g_mutex_lock (&self->lock);
+
+  if (gst_clapper_mpris_media_player2_player_get_can_play (
+          self->player_skeleton) != self->can_play) {
+    /* "can-play" is bound with "can-pause" */
+    GST_DEBUG_OBJECT (self, "CanPlay/CanPause: %s", self->can_play ? "yes" : "no");
+    gst_clapper_mpris_media_player2_player_set_can_play (
+        self->player_skeleton, self->can_play);
+  }
+  if (strcmp (gst_clapper_mpris_media_player2_player_get_playback_status (
+          self->player_skeleton), self->playback_status) != 0) {
+    GST_DEBUG_OBJECT (self, "PlaybackStatus: %s", self->playback_status);
+    gst_clapper_mpris_media_player2_player_set_playback_status (
+        self->player_skeleton, self->playback_status);
+  }
+
+  g_mutex_unlock (&self->lock);
+
+  return G_SOURCE_REMOVE;
+}
+
+static void
+mpris_dispatcher_update_dispatch (GstClapperMpris * self)
+{
+  if (!self->name_id)
+    return;
+
+  GST_DEBUG_OBJECT (self, "Queued update props dispatch");
+
+  g_main_context_invoke_full (self->context,
+      G_PRIORITY_DEFAULT, mpris_update_props_dispatch,
+      g_object_ref (self), g_object_unref);
+}
+
+static gpointer
+gst_clapper_mpris_main (gpointer data)
+{
+  GstClapperMpris *self = GST_CLAPPER_MPRIS (data);
+
+  GDBusConnectionFlags flags;
+  GDBusConnection *connection;
+  GSource *source;
+  gchar *address;
+
+  GST_TRACE_OBJECT (self, "Starting main thread");
+
+  g_main_context_push_thread_default (self->context);
+
+  source = g_idle_source_new ();
+  g_source_set_callback (source, (GSourceFunc) main_loop_running_cb, self,
+      NULL);
+  g_source_attach (source, self->context);
+  g_source_unref (source);
+
+  address = g_dbus_address_get_for_bus_sync (G_BUS_TYPE_SESSION, NULL, NULL);
+  if (!address) {
+    GST_WARNING_OBJECT (self, "No MPRIS bus address");
+    goto no_mpris;
+  }
+
+  GST_DEBUG_OBJECT (self, "Obtained MPRIS DBus address");
+
+  flags = G_DBUS_CONNECTION_FLAGS_AUTHENTICATION_CLIENT |
+      G_DBUS_CONNECTION_FLAGS_MESSAGE_BUS_CONNECTION;
+  connection = g_dbus_connection_new_for_address_sync (address,
+      flags, NULL, NULL, NULL);
+  g_free (address);
+
+  if (!connection) {
+    GST_WARNING_OBJECT (self, "No MPRIS bus connection");
+    goto no_mpris;
+  }
+
+  GST_DEBUG_OBJECT (self, "Obtained MPRIS DBus connection");
+
+  self->name_id = g_bus_own_name_on_connection (connection, self->own_name,
+      G_BUS_NAME_OWNER_FLAGS_NONE,
+      (GBusNameAcquiredCallback) name_acquired_cb,
+      (GBusNameLostCallback) name_lost_cb,
+      self, NULL);
+  g_object_unref (connection);
+  goto done;
+
+no_mpris:
+  g_warning ("GstClapperMpris: failed to create DBus connection");
+
+done:
+  GST_TRACE_OBJECT (self, "Starting main loop");
+  g_main_loop_run (self->loop);
+  GST_TRACE_OBJECT (self, "Stopped main loop");
+
+  unregister (self);
+  g_main_context_pop_thread_default (self->context);
+
+  GST_TRACE_OBJECT (self, "Stopped main thread");
+
+  return NULL;
+}
+
+void
+gst_clapper_mpris_set_clapper (GstClapperMpris * self, GstClapper * clapper)
+{
+  g_signal_connect (self->player_skeleton, "handle-play",
+      G_CALLBACK (handle_play_cb), clapper);
+  g_signal_connect (self->player_skeleton, "handle-pause",
+      G_CALLBACK (handle_pause_cb), clapper);
+  g_signal_connect (self->player_skeleton, "handle-play-pause",
+      G_CALLBACK (handle_play_pause_cb), clapper);
+}
+
+void
+gst_clapper_mpris_set_playback_status (GstClapperMpris * self, const gchar * status)
+{
+  g_mutex_lock (&self->lock);
+
+  if (strcmp (self->playback_status, status) == 0) {
+    g_mutex_unlock (&self->lock);
+    return;
+  }
+  g_free (self->playback_status);
+  self->playback_status = g_strdup (status);
+  self->can_play = strcmp (status, "Stopped") != 0;
+
+  g_mutex_unlock (&self->lock);
+
+  mpris_dispatcher_update_dispatch (self);
+}
+
+/**
+ * gst_clapper_mpris_new:
+ * @own_name: DBus own name
+ * @id_path: DBus id path used for prefix
+ * @identity: (allow-none): friendly name
+ * @desktop_entry: (allow-none): Desktop entry filename
+ * @default_art_url: (allow-none): filepath to default art
+ *
+ * Creates a new #GstClapperMpris instance.
+ *
+ * Returns: (transfer full): a new #GstClapperMpris instance
+ */
+GstClapperMpris *
+gst_clapper_mpris_new (const gchar * own_name, const gchar * id_path,
+    const gchar * identity, const gchar * desktop_entry,
+    const gchar * default_art_url)
+{
+  GstClapperMpris *self;
+
+  self = g_object_new (GST_TYPE_CLAPPER,
+      "own-name", own_name, "id_path", id_path,
+      "identity", identity, "desktop-entry", desktop_entry,
+      "default-art-url", default_art_url, NULL);
+
+  return self;
+}

lib/gst/clapper/gstclapper-mpris.h

@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2021 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * 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., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __GST_CLAPPER_MPRIS_H__
+#define __GST_CLAPPER_MPRIS_H__
+
+#include <glib.h>
+#include <gio/gio.h>
+
+#include <gst/clapper/clapper-prelude.h>
+
+G_BEGIN_DECLS
+
+typedef struct _GstClapperMpris GstClapperMpris;
+typedef struct _GstClapperMprisClass GstClapperMprisClass;
+
+#define GST_TYPE_CLAPPER_MPRIS             (gst_clapper_mpris_get_type ())
+#define GST_IS_CLAPPER_MPRIS(obj)          (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_CLAPPER_MPRIS))
+#define GST_IS_CLAPPER_MPRIS_CLASS(klass)  (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_CLAPPER_MPRIS))
+#define GST_CLAPPER_MPRIS_GET_CLASS(obj)   (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_CLAPPER_MPRIS, GstClapperMprisClass))
+#define GST_CLAPPER_MPRIS(obj)             (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_CLAPPER_MPRIS, GstClapperMpris))
+#define GST_CLAPPER_MPRIS_CLASS(klass)     (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_CLAPPER_MPRIS, GstClapperMprisClass))
+#define GST_CLAPPER_MPRIS_CAST(obj)        ((GstClapperMpris*)(obj))
+
+#ifdef G_DEFINE_AUTOPTR_CLEANUP_FUNC
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(GstClapperMpris, g_object_unref)
+#endif
+
+GST_CLAPPER_API
+GType gst_clapper_mpris_get_type                      (void);
+
+GST_CLAPPER_API
+GstClapperMpris * gst_clapper_mpris_new               (const gchar *own_name, const gchar *id_path, const gchar *identity,
+                                                          const gchar *desktop_entry, const gchar *default_art_url);
+
+G_END_DECLS
+
+#endif /* __GST_CLAPPER_MPRIS_H__ */

lib/gst/clapper/gstclapper.c

@@ -46,6 +46,7 @@
 #include "gstclapper-signal-dispatcher-private.h"
 #include "gstclapper-video-renderer-private.h"
 #include "gstclapper-media-info-private.h"
+#include "gstclapper-mpris-private.h"
 
 GST_DEBUG_CATEGORY_STATIC (gst_clapper_debug);
 #define GST_CAT_DEFAULT gst_clapper_debug
@@ -76,6 +77,7 @@ enum
   PROP_0,
   PROP_VIDEO_RENDERER,
   PROP_SIGNAL_DISPATCHER,
+  PROP_MPRIS,
   PROP_STATE,
   PROP_URI,
   PROP_SUBURI,
@@ -127,6 +129,7 @@ struct _GstClapper
 
   GstClapperVideoRenderer *video_renderer;
   GstClapperSignalDispatcher *signal_dispatcher;
+  GstClapperMpris *mpris;
 
   gchar *uri;
   gchar *redirect_uri;
@@ -305,6 +308,13 @@ gst_clapper_class_init (GstClapperClass * klass)
       G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY |
       G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
 
+  param_specs[PROP_MPRIS] =
+      g_param_spec_object ("mpris",
+      "MPRIS", "Clapper MPRIS for playback control over DBus",
+      GST_TYPE_CLAPPER_MPRIS,
+      G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY |
+      G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
   param_specs[PROP_STATE] =
       g_param_spec_enum ("state", "Clapper State", "Current player state",
       GST_TYPE_CLAPPER_STATE, DEFAULT_STATE, G_PARAM_READABLE |
@@ -491,7 +501,7 @@ gst_clapper_finalize (GObject * object)
 {
   GstClapper *self = GST_CLAPPER (object);
 
-  GST_TRACE_OBJECT (self, "Finalizing");
+  GST_TRACE_OBJECT (self, "Finalize");
 
   g_free (self->uri);
   g_free (self->redirect_uri);
@@ -507,6 +517,8 @@ gst_clapper_finalize (GObject * object)
     g_object_unref (self->video_renderer);
   if (self->signal_dispatcher)
     g_object_unref (self->signal_dispatcher);
+  if (self->mpris)
+    g_object_unref (self->mpris);
   if (self->current_vis_element)
     gst_object_unref (self->current_vis_element);
   if (self->collection)
@@ -649,6 +661,9 @@ gst_clapper_set_property (GObject * object, guint prop_id,
     case PROP_SIGNAL_DISPATCHER:
       self->signal_dispatcher = g_value_dup_object (value);
       break;
+    case PROP_MPRIS:
+      self->mpris = g_value_dup_object (value);
+      break;
     case PROP_URI:{
       g_mutex_lock (&self->lock);
       g_free (self->uri);
@@ -741,6 +756,9 @@ gst_clapper_get_property (GObject * object, guint prop_id,
   GstClapper *self = GST_CLAPPER (object);
 
   switch (prop_id) {
+    case PROP_MPRIS:
+      g_value_set_object (value, self->mpris);
+      break;
     case PROP_STATE:
       g_mutex_lock (&self->lock);
       g_value_set_enum (value, self->app_state);
@@ -980,6 +998,23 @@ change_state (GstClapper * self, GstClapperState state)
         state_changed_dispatch, data,
         (GDestroyNotify) state_changed_signal_data_free);
   }
+
+  if (!self->mpris)
+    return;
+
+  switch (state) {
+    case GST_CLAPPER_STATE_STOPPED:
+      gst_clapper_mpris_set_playback_status (self->mpris, "Stopped");
+      break;
+    case GST_CLAPPER_STATE_PAUSED:
+      gst_clapper_mpris_set_playback_status (self->mpris, "Paused");
+      break;
+    case GST_CLAPPER_STATE_PLAYING:
+      gst_clapper_mpris_set_playback_status (self->mpris, "Playing");
+      break;
+    default:
+      break;
+  }
 }
 
 typedef struct
@@ -2925,6 +2960,9 @@ gst_clapper_main (gpointer data)
   self->bus = bus = gst_element_get_bus (self->playbin);
   gst_bus_add_signal_watch (bus);
 
+  if (self->mpris)
+    gst_clapper_mpris_set_clapper (self->mpris, self);
+
   g_signal_connect (G_OBJECT (bus), "message::error", G_CALLBACK (error_cb),
       self);
   g_signal_connect (G_OBJECT (bus), "message::warning", G_CALLBACK (warning_cb),
@@ -3025,6 +3063,7 @@ gst_clapper_main (gpointer data)
  * gst_clapper_new:
  * @video_renderer: (transfer full) (allow-none): GstClapperVideoRenderer to use
  * @signal_dispatcher: (transfer full) (allow-none): GstClapperSignalDispatcher to use
+ * @mpris: (transfer full) (allow-none): GstClapperMpris to use
  *
  * Creates a new #GstClapper instance that uses @signal_dispatcher to dispatch
  * signals to some event loop system, or emits signals directly if NULL is
@@ -3038,18 +3077,20 @@ gst_clapper_main (gpointer data)
  */
 GstClapper *
 gst_clapper_new (GstClapperVideoRenderer * video_renderer,
-    GstClapperSignalDispatcher * signal_dispatcher)
+    GstClapperSignalDispatcher * signal_dispatcher,
+    GstClapperMpris * mpris)
 {
   GstClapper *self;
 
-  self =
+  self = g_object_new (GST_TYPE_CLAPPER, "video-renderer", video_renderer,
-      g_object_new (GST_TYPE_CLAPPER, "video-renderer", video_renderer,
+      "signal-dispatcher", signal_dispatcher, "mpris", mpris, NULL);
-      "signal-dispatcher", signal_dispatcher, NULL);
 
   if (video_renderer)
     g_object_unref (video_renderer);
   if (signal_dispatcher)
     g_object_unref (signal_dispatcher);
+  if (mpris)
+    g_object_unref (mpris);
 
   return self;
 }
@@ -3701,6 +3742,28 @@ gst_clapper_get_pipeline (GstClapper * self)
   return val;
 }
 
+/**
+ * gst_clapper_get_mpris:
+ * @clapper: #GstClapper instance
+ *
+ * A Function to get the #GstClapperMpris instance.
+ *
+ * Returns: (transfer full): mpris instance.
+ *
+ * The caller should free it with g_object_unref()
+ */
+GstClapperMpris *
+gst_clapper_get_mpris (GstClapper * self)
+{
+  GstClapperMpris *val;
+
+  g_return_val_if_fail (GST_IS_CLAPPER (self), NULL);
+
+  g_object_get (self, "mpris", &val, NULL);
+
+  return val;
+}
+
 /**
  * gst_clapper_get_media_info:
  * @clapper: #GstClapper instance

lib/gst/clapper/gstclapper.h

@@ -30,6 +30,7 @@
 #include <gst/clapper/gstclapper-signal-dispatcher.h>
 #include <gst/clapper/gstclapper-video-renderer.h>
 #include <gst/clapper/gstclapper-media-info.h>
+#include <gst/clapper/gstclapper-mpris.h>
 
 G_BEGIN_DECLS
 
@@ -153,7 +154,8 @@ GST_CLAPPER_API
 GType        gst_clapper_get_type                           (void);
 
 GST_CLAPPER_API
-GstClapper * gst_clapper_new                                (GstClapperVideoRenderer *video_renderer, GstClapperSignalDispatcher *signal_dispatcher);
+GstClapper * gst_clapper_new                                (GstClapperVideoRenderer *video_renderer, GstClapperSignalDispatcher *signal_dispatcher,
+                                                                GstClapperMpris *mpris);
 
 GST_CLAPPER_API
 void         gst_clapper_play                               (GstClapper *clapper);
@@ -220,6 +222,10 @@ void         gst_clapper_set_mute                           (GstClapper *clapper
 GST_CLAPPER_API
 GstElement * gst_clapper_get_pipeline                       (GstClapper *clapper);
 
+GST_CLAPPER_API
+GstClapperMpris *
+             gst_clapper_get_mpris                          (GstClapper *clapper);
+
 GST_CLAPPER_API
 void         gst_clapper_set_video_track_enabled            (GstClapper *clapper, gboolean enabled);
 

lib/gst/clapper/meson.build

@@ -1,3 +1,5 @@
+gnome = import('gnome')
+
 gstclapper_sources = [
   'gstclapper.c',
   'gstclapper-signal-dispatcher.c',
@@ -6,6 +8,7 @@ gstclapper_sources = [
   'gstclapper-g-main-context-signal-dispatcher.c',
   'gstclapper-video-overlay-video-renderer.c',
   'gstclapper-visualization.c',
+  'gstclapper-mpris.c',
   'gstclapper-gtk4-plugin.c',
 
   'gtk4/gstclapperglsink.c',
@@ -23,6 +26,7 @@ gstclapper_headers = [
   'gstclapper-g-main-context-signal-dispatcher.h',
   'gstclapper-video-overlay-video-renderer.h',
   'gstclapper-visualization.h',
+  'gstclapper-mpris.h',
   'gstclapper-gtk4-plugin.h',
 ]
 gstclapper_defines = [
@@ -67,15 +71,22 @@ if not have_gtk_gl_windowing
   error('GTK4 widget requires GL windowing')
 endif
 
+gstclapper_mpris_gdbus = gnome.gdbus_codegen('gstclapper-mpris-gdbus',
+  sources: '../../../data/gstclapper-mpris-gdbus.xml',
+  interface_prefix: 'org.mpris.',
+  namespace: 'GstClapperMpris'
+)
+
 gstclapper = library('gstclapper-' + api_version,
-  gstclapper_sources,
+  gstclapper_sources + gstclapper_mpris_gdbus,
   c_args : gstclapper_defines,
   link_args : noseh_link_args,
   include_directories : [configinc, libsinc],
   version : libversion,
   install : true,
   install_dir : clapper_libdir,
-  dependencies : [gtk4_dep, gstbase_dep, gstvideo_dep, gstaudio_dep,
+  dependencies : [gtk4_dep, glib_dep, gio_dep,
+    gstbase_dep, gstvideo_dep, gstaudio_dep,
     gsttag_dep, gstpbutils_dep, libm] + gtk_deps,
 )
 

pkgs/flatpak/com.github.rafostar.Clapper.json

@@ -13,6 +13,7 @@
         "--share=network",
         "--device=all",
         "--filesystem=xdg-videos",
+        "--own-name=org.mpris.MediaPlayer2.Clapper",
         "--talk-name=org.gnome.Shell",
         "--env=GST_PLUGIN_SYSTEM_PATH=/app/lib/gstreamer-1.0",
         "--env=GST_VAAPI_ALL_DRIVERS=1"

src/misc.js

@@ -1,4 +1,4 @@
-const { Gio, Gdk, Gtk } = imports.gi;
+const { Gio, GLib, Gdk, Gtk } = imports.gi;
 const Debug = imports.src.debug;
 
 const { debug } = Debug;
@@ -39,6 +39,57 @@ function getClapperVersion()
         : '';
 }
 
+function getClapperThemeIconUri()
+{
+    const display = Gdk.Display.get_default();
+    if(!display) return null;
+
+    const iconTheme = Gtk.IconTheme.get_for_display(display);
+    if(!iconTheme || !iconTheme.has_icon(appId))
+        return null;
+
+    const iconPaintable = iconTheme.lookup_icon(appId, null, 256, 1,
+        Gtk.TextDirection.NONE, Gtk.IconLookupFlags.FORCE_REGULAR
+    );
+    const iconFile = iconPaintable.get_file();
+    if(!iconFile) return null;
+
+    const iconPath = iconFile.get_path();
+    if(!iconPath) return null;
+
+    let substractName = iconPath.substring(
+        iconPath.indexOf('/icons/') + 7, iconPath.indexOf('/scalable/')
+    );
+    if(!substractName || substractName.includes('/'))
+        return null;
+
+    substractName = substractName.toLowerCase();
+    const postFix = (substractName === iconTheme.theme_name.toLowerCase())
+        ? substractName
+        : 'hicolor';
+    const cacheIconName = `clapper-${postFix}.svg`;
+
+    /* We need to have this icon placed in a folder
+     * accessible from both app runtime and gnome-shell */
+    const expectedFile = Gio.File.new_for_path(
+        GLib.get_user_cache_dir() + `/${appId}/icons/${cacheIconName}`
+    );
+    if(!expectedFile.query_exists(null)) {
+        debug('no cached icon file');
+
+        const dirPath = expectedFile.get_parent().get_path();
+        GLib.mkdir_with_parents(dirPath, 493); // octal 755
+        iconFile.copy(expectedFile,
+            Gio.FileCopyFlags.TARGET_DEFAULT_PERMS, null, null
+        );
+        debug(`icon copied to cache dir: ${cacheIconName}`);
+    }
+    const iconUri = expectedFile.get_uri();
+    debug(`using cached clapper icon uri: ${iconUri}`);
+
+    return iconUri;
+}
+
 function loadCustomCss()
 {
     const clapperPath = getClapperPath();

src/player.js

@@ -20,14 +20,18 @@ class ClapperPlayer extends GstClapper.Clapper
         const glsinkbin = Gst.ElementFactory.make('glsinkbin', null);
         glsinkbin.sink = gtk4plugin.video_sink;
 
-        const dispatcher = new GstClapper.ClapperGMainContextSignalDispatcher();
-        const renderer = new GstClapper.ClapperVideoOverlayVideoRenderer({
-            video_sink: glsinkbin
-        });
-
         super._init({
-            signal_dispatcher: dispatcher,
+            signal_dispatcher: new GstClapper.ClapperGMainContextSignalDispatcher(),
-            video_renderer: renderer
+            video_renderer: new GstClapper.ClapperVideoOverlayVideoRenderer({
+                video_sink: glsinkbin,
+            }),
+            mpris: new GstClapper.ClapperMpris({
+                own_name: `org.mpris.MediaPlayer2.${Misc.appName}`,
+                id_path: '/' + Misc.appId.replace(/\./g, '/'),
+                identity: Misc.appName,
+                desktop_entry: Misc.appId,
+                default_art_url: Misc.getClapperThemeIconUri(),
+            }),
         });
 
         this.widget = gtk4plugin.video_sink.widget;