From a2a4067e07311e9f74ac8744027601ccba69c496 Mon Sep 17 00:00:00 2001
From: Pascal Nowack <Pascal.Nowack@gmx.de>
Date: Fri, 29 Sep 2023 12:33:17 +0200
Subject: [PATCH] screencast: Add ability to stop streams

When a stream is destroyed by a consumer, mutter won't be able to
recognize that.
For mutter, the stream just paused, but did not disconnect, because the
connection state of a PipeWire stream only represents, whether the
respective PipeWire context is connected to PipeWire.
In addition to that, it may be the case, that the stream consumer just
recreates the stream.
So even if mutter would be able to know, when the stream consumer
destroyed a stream, but not the whole screencast or remote-desktop
session, then mutter would not know, whether the stream will be resumed
eventually or not.

So, add an explicit API call to the screencast interface to stop a
stream.
For virtual streams, this also means, that the respective virtual
monitor is destroyed.

Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/2889
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3307>
---
 .../org.gnome.Mutter.ScreenCast.xml           |  8 ++++++
 src/backends/meta-screen-cast-stream.c        | 25 +++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/data/dbus-interfaces/org.gnome.Mutter.ScreenCast.xml b/data/dbus-interfaces/org.gnome.Mutter.ScreenCast.xml
index 345650732..4d8936c38 100644
--- a/data/dbus-interfaces/org.gnome.Mutter.ScreenCast.xml
+++ b/data/dbus-interfaces/org.gnome.Mutter.ScreenCast.xml
@@ -199,6 +199,14 @@
     -->
     <method name="Start"/>
 
+    <!--
+        Stop:
+        @short_description: Stop the stream
+
+        Stop the started stream.
+    -->
+    <method name="Stop"/>
+
     <!--
         PipeWireStreamAdded:
         @short_description: Pipewire stream added
diff --git a/src/backends/meta-screen-cast-stream.c b/src/backends/meta-screen-cast-stream.c
index 0006a9574..b3c8b8385 100644
--- a/src/backends/meta-screen-cast-stream.c
+++ b/src/backends/meta-screen-cast-stream.c
@@ -396,10 +396,35 @@ handle_start (MetaDBusScreenCastStream *skeleton,
   return TRUE;
 }
 
+static gboolean
+handle_stop (MetaDBusScreenCastStream *skeleton,
+             GDBusMethodInvocation    *invocation)
+{
+  MetaScreenCastStream *stream = META_SCREEN_CAST_STREAM (skeleton);
+  MetaScreenCastStreamPrivate *priv =
+    meta_screen_cast_stream_get_instance_private (stream);
+
+  if (!check_permission (stream, invocation))
+    {
+      g_dbus_method_invocation_return_error (invocation, G_DBUS_ERROR,
+                                             G_DBUS_ERROR_ACCESS_DENIED,
+                                             "Permission denied");
+      return G_DBUS_METHOD_INVOCATION_HANDLED;
+    }
+
+  if (priv->src)
+    meta_screen_cast_stream_close (stream);
+
+  meta_dbus_screen_cast_stream_complete_stop (skeleton, invocation);
+
+  return G_DBUS_METHOD_INVOCATION_HANDLED;
+}
+
 static void
 meta_screen_cast_stream_init_iface (MetaDBusScreenCastStreamIface *iface)
 {
   iface->handle_start = handle_start;
+  iface->handle_stop = handle_stop;
 }
 
 static gboolean