[GLIB] MediaSessionGlib shows multiple players for a single video

https://bugs.webkit.org/show_bug.cgi?id=241857

Patch by Philippe Normand <philn@igalia.com> on 2022-06-23
Reviewed by Carlos Garcia Campos.

The MediaSession is now registered on DBus lazily, only if any of its properties changes.

* Source/WebCore/platform/audio/glib/MediaSessionGLib.cpp:
(WebCore::MediaSessionGLib::MediaSessionGLib):
(WebCore::MediaSessionGLib::~MediaSessionGLib):
(WebCore::MediaSessionGLib::ensureMprisSessionRegistered):
(WebCore::MediaSessionGLib::emitPositionChanged):
(WebCore::MediaSessionGLib::emitPropertiesChanged):
* Source/WebCore/platform/audio/glib/MediaSessionGLib.h:

Canonical link: https://commits.webkit.org/251779@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@295774 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebCore/platform/audio/glib/MediaSessionGLib.cpp

@@ -200,7 +200,23 @@ MediaSessionGLib::MediaSessionGLib(MediaSessionManagerGLib& manager, GRefPtr<GDB
     , m_manager(manager)
     , m_connection(WTFMove(connection))
 {
-    if (!m_connection)
+}
+
+MediaSessionGLib::~MediaSessionGLib()
+{
+    if (m_connection) {
+        if (m_rootRegistrationId && !g_dbus_connection_unregister_object(m_connection.get(), m_rootRegistrationId))
+            g_warning("Unable to unregister MPRIS D-Bus object.");
+        if (m_playerRegistrationId && !g_dbus_connection_unregister_object(m_connection.get(), m_playerRegistrationId))
+            g_warning("Unable to unregister MPRIS D-Bus player object.");
+    }
+    if (m_ownerId)
+        g_bus_unown_name(m_ownerId);
+}
+
+void MediaSessionGLib::ensureMprisSessionRegistered()
+{
+    if (m_ownerId || !m_connection)
         return;
 
     const auto& mprisInterface = m_manager.mprisInterface();
@@ -222,28 +238,18 @@ MediaSessionGLib::MediaSessionGLib(MediaSessionManagerGLib& manager, GRefPtr<GDB
     }
 
     const auto& applicationID = getApplicationID();
-    m_instanceId = applicationID.isEmpty() ? makeString("org.mpris.MediaPlayer2.webkit.instance", getpid(), "-", identifier.toUInt64()) : makeString("org.mpris.MediaPlayer2.", applicationID.ascii().data(), ".instance-", identifier.toUInt64());
+    m_instanceId = applicationID.isEmpty() ? makeString("org.mpris.MediaPlayer2.webkit.instance", getpid(), "-", m_identifier.toUInt64()) : makeString("org.mpris.MediaPlayer2.", applicationID.ascii().data(), ".instance-", m_identifier.toUInt64());
 
     m_ownerId = g_bus_own_name_on_connection(m_connection.get(), m_instanceId.ascii().data(), G_BUS_NAME_OWNER_FLAGS_NONE, nullptr, nullptr, this, nullptr);
 }
 
-MediaSessionGLib::~MediaSessionGLib()
-{
-    if (m_connection) {
-        if (m_rootRegistrationId && !g_dbus_connection_unregister_object(m_connection.get(), m_rootRegistrationId))
-            g_warning("Unable to unregister MPRIS D-Bus object.");
-        if (m_playerRegistrationId && !g_dbus_connection_unregister_object(m_connection.get(), m_playerRegistrationId))
-            g_warning("Unable to unregister MPRIS D-Bus player object.");
-    }
-    if (m_ownerId)
-        g_bus_unown_name(m_ownerId);
-}
-
 void MediaSessionGLib::emitPositionChanged(double time)
 {
     if (!m_connection)
         return;
 
+    ensureMprisSessionRegistered();
+
     GUniqueOutPtr<GError> error;
     int64_t position = time * 1000000;
     if (!g_dbus_connection_emit_signal(m_connection.get(), nullptr, DBUS_MPRIS_OBJECT_PATH, DBUS_MPRIS_PLAYER_INTERFACE, "Seeked", g_variant_new("(x)", position), &error.outPtr()))
@@ -320,6 +326,8 @@ void MediaSessionGLib::emitPropertiesChanged(GVariant* parameters)
     if (!m_connection)
         return;
 
+    ensureMprisSessionRegistered();
+
     GUniqueOutPtr<GError> error;
     if (!g_dbus_connection_emit_signal(m_connection.get(), nullptr, DBUS_MPRIS_OBJECT_PATH, "org.freedesktop.DBus.Properties", "PropertiesChanged", parameters, &error.outPtr()))
         g_warning("Failed to emit MPRIS properties changed: %s", error->message);

Source/WebCore/platform/audio/glib/MediaSessionGLib.h

@@ -51,6 +51,7 @@ class MediaSessionGLib {
 private:
     void emitPropertiesChanged(GVariant*);
     std::optional<NowPlayingInfo> nowPlayingInfo();
+    void ensureMprisSessionRegistered();
 
     MediaSessionIdentifier m_identifier;
     MediaSessionManagerGLib& m_manager;