[gnome-music] player: Music pauses when system is going to suspend

[Marinus Schraal <mschraal src gnome org>]

commit 6bf7eecd0848627e49d247dd84b629a24ffcd07b
Author: Nikolay Yanchuk <russial2011 gmail com>
Date:   Sat Sep 15 20:31:20 2018 +0300

    player: Music pauses when system is going to suspend
    
    Currently music continues after system suspend.
    This feature pauses music on logind "PrepareForSleep" signal.
    Flatpak changed in order to be able to listen logind signals.
    
    Closes: #68

 gnomemusic/pauseonsuspend.py | 144 +++++++++++++++++++++++++++++++++++++++++++
 gnomemusic/player.py         |   2 +
 org.gnome.Music.json         |   3 +-
 3 files changed, 148 insertions(+), 1 deletion(-)
---
diff --git a/gnomemusic/pauseonsuspend.py b/gnomemusic/pauseonsuspend.py
new file mode 100644
index 00000000..eafe3df0
--- /dev/null
+++ b/gnomemusic/pauseonsuspend.py
@@ -0,0 +1,144 @@
+# Copyright 2019 The GNOME Music developers
+# GNOME Music is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# GNOME Music 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with GNOME Music; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+#
+# The GNOME Music authors hereby grant permission for non-GPL compatible
+# GStreamer plugins to be used and distributed together with GStreamer
+# and GNOME Music.  This permission is above and beyond the permissions
+# granted by the GPL license by which GNOME Music is covered.  If you
+# modify this code, you may extend this exception to your version of the
+# code, but you are not obligated to do so.  If you do not wish to do so,
+# delete this exception statement from your version.
+
+import os
+
+from gi.repository import GLib, Gio, GObject
+import logging
+
+from gnomemusic import log
+from gnomemusic.gstplayer import Playback
+
+logger = logging.getLogger(__name__)
+
+
+class PauseOnSuspend(GObject.GObject):
+    """PauseOnSuspend object
+
+    Contains logic to pause music on system suspend
+    and inhibit suspend before pause.
+    """
+
+    def __repr__(self):
+        return '<PauseOnSuspend>'
+
+    @log
+    def __init__(self, player):
+        """Initialize pause on supend handling
+
+        :param Player player: Player object
+        """
+        super().__init__()
+
+        self._player = player
+        self._init_pause_on_suspend()
+
+        self._connection = None
+        self._file_descriptor = -1
+        self._suspend_proxy = None
+        self._previous_state = self._player.props.state
+        self._player.connect("notify::state", self._on_player_state_changed)
+
+    @log
+    def _on_player_state_changed(self, klass, arguments):
+        new_state = self._player.props.state
+        if self._previous_state == new_state:
+            return
+
+        if (new_state == Playback.PLAYING
+                and self._file_descriptor == -1):
+            self._take_lock()
+
+        if (self._previous_state == Playback.PLAYING
+                and new_state != Playback.LOADING):
+            self._release_lock()
+
+        self._previous_state = new_state
+
+    @log
+    def _take_lock(self):
+        variant = GLib.Variant(
+            "(ssss)",
+            (
+                "sleep",
+                "GNOME Music",
+                "GNOME Music is pausing",
+                "delay"
+            )
+        )
+
+        self._suspend_proxy.call(
+            "Inhibit", variant, Gio.DBusCallFlags.NONE,
+            -1, None, self._on_inhibit)
+
+    @log
+    def _on_inhibit(self, proxy, task, data=None):
+        if not self._suspend_proxy:
+            return
+
+        try:
+            var = self._suspend_proxy.call_with_unix_fd_list_finish(task)
+            self._file_descriptor = var.out_fd_list.get(0)
+            self._connection = self._suspend_proxy.connect(
+                "g-signal", self._pause_playing)
+        except GLib.Error as e:
+            logger.warning(
+                "Error: Failed to finish proxy call:", e.message)
+
+    @log
+    def _release_lock(self):
+        if self._file_descriptor >= 0:
+            os.close(self._file_descriptor)
+            self._file_descriptor = -1
+            self._suspend_proxy.disconnect(self._connection)
+
+    @log
+    def _init_pause_on_suspend(self):
+        Gio.DBusProxy.new_for_bus(
+            Gio.BusType.SYSTEM,
+            Gio.DBusProxyFlags.DO_NOT_LOAD_PROPERTIES, None,
+            "org.freedesktop.login1",
+            "/org/freedesktop/login1",
+            "org.freedesktop.login1.Manager", None,
+            self._suspend_proxy_ready)
+
+    @log
+    def _suspend_proxy_ready(self, proxy, result, data=None):
+        try:
+            self._suspend_proxy = proxy.new_finish(result)
+        except GLib.Error as e:
+            logger.warning(
+                "Error: Failed to contact logind daemon:", e.message)
+            return
+
+    @log
+    def _pause_playing(self, proxy, sender, signal, parameters):
+        if signal != "PrepareForSleep":
+            return
+
+        (going_to_sleep, ) = parameters
+        if going_to_sleep is True:
+            self._player.pause()
+            self._release_lock()
+        else:
+            self._take_lock()
diff --git a/gnomemusic/player.py b/gnomemusic/player.py
index 7e72bcc9..77d066ba 100644
--- a/gnomemusic/player.py
+++ b/gnomemusic/player.py
@@ -39,6 +39,7 @@ from gnomemusic import log
 from gnomemusic.gstplayer import GstPlayer, Playback
 from gnomemusic.grilo import grilo
 from gnomemusic.inhibitsuspend import InhibitSuspend
+from gnomemusic.pauseonsuspend import PauseOnSuspend
 from gnomemusic.playlists import Playlists
 from gnomemusic.scrobbler import LastFmScrobbler
 
@@ -590,6 +591,7 @@ class Player(GObject.GObject):
 
         root_window = parent_window.get_toplevel()
         self._inhibit_suspend = InhibitSuspend(root_window, self)
+        self._pause_on_suspend = PauseOnSuspend(self)
 
         self._lastfm = LastFmScrobbler()
 
diff --git a/org.gnome.Music.json b/org.gnome.Music.json
index ff490e9e..644067a8 100644
--- a/org.gnome.Music.json
+++ b/org.gnome.Music.json
@@ -21,7 +21,8 @@
         "--talk-name=org.gtk.vfs.mountpoint_http",
         "--socket=pulseaudio",
         "--filesystem=xdg-music",
-        "--filesystem=xdg-cache/media-art"
+        "--filesystem=xdg-cache/media-art",
+        "--system-talk-name=org.freedesktop.login1"
     ],
     "cleanup": [
         "/include",