[gnome-remote-desktop] pipewire-utils: Add helper function for creating PipeWire source

[Jonas Ådahl <jadahl src gnome org>]

commit 545261bf10a93666be0f0db98321cf45a0ee8a94
Author: Pascal Nowack <Pascal Nowack gmx de>
Date:   Tue Jul 12 08:22:27 2022 +0200

    pipewire-utils: Add helper function for creating PipeWire source
    
    The creation of the PipeWire source happens in several classes now and
    will be done in the future in more classes.
    To avoid code duplication, add a helper function for the PipeWire
    source creation.

 src/grd-pipewire-utils.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/grd-pipewire-utils.h |  4 +++
 2 files changed, 94 insertions(+)
---
diff --git a/src/grd-pipewire-utils.c b/src/grd-pipewire-utils.c
index 24cca494..bc303521 100644
--- a/src/grd-pipewire-utils.c
+++ b/src/grd-pipewire-utils.c
@@ -24,6 +24,96 @@
 
 #include <drm_fourcc.h>
 #include <spa/param/video/raw.h>
+#include <spa/utils/result.h>
+
+static void pipewire_source_unref (GrdPipeWireSource *pipewire_source);
+
+G_DEFINE_AUTOPTR_CLEANUP_FUNC (GrdPipeWireSource, pipewire_source_unref)
+
+static gboolean
+pipewire_loop_source_prepare (GSource *base,
+                              int     *timeout)
+{
+  *timeout = -1;
+
+  return FALSE;
+}
+
+static gboolean
+pipewire_loop_source_dispatch (GSource     *source,
+                               GSourceFunc  callback,
+                               gpointer     user_data)
+{
+  GrdPipeWireSource *pipewire_source = (GrdPipeWireSource *) source;
+  int result;
+
+  result = pw_loop_iterate (pipewire_source->pipewire_loop, 0);
+  if (result < 0)
+    {
+      g_warning ("%s pw_loop_iterate() failed: %s", pipewire_source->message_tag,
+                 spa_strerror (result));
+    }
+
+  return TRUE;
+}
+
+static void
+pipewire_loop_source_finalize (GSource *source)
+{
+  GrdPipeWireSource *pipewire_source = (GrdPipeWireSource *) source;
+
+  if (pipewire_source->pipewire_loop)
+    {
+      pw_loop_leave (pipewire_source->pipewire_loop);
+      pw_loop_destroy (pipewire_source->pipewire_loop);
+    }
+  g_clear_pointer (&pipewire_source->message_tag, g_free);
+}
+
+static GSourceFuncs pipewire_source_funcs =
+{
+  pipewire_loop_source_prepare,
+  NULL,
+  pipewire_loop_source_dispatch,
+  pipewire_loop_source_finalize,
+};
+
+GrdPipeWireSource *
+grd_attached_pipewire_source_new (const char  *message_tag,
+                                  GError     **error)
+{
+  g_autoptr (GrdPipeWireSource) pipewire_source = NULL;
+
+  g_assert (strlen (message_tag) > 0);
+
+  pipewire_source =
+    (GrdPipeWireSource *) g_source_new (&pipewire_source_funcs,
+                                        sizeof (GrdPipeWireSource));
+  pipewire_source->message_tag = g_strdup_printf ("[%s]", message_tag);
+
+  pipewire_source->pipewire_loop = pw_loop_new (NULL);
+  if (!pipewire_source->pipewire_loop)
+    {
+      g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
+                   "Failed to create PipeWire loop");
+      return NULL;
+    }
+
+  g_source_add_unix_fd (&pipewire_source->base,
+                        pw_loop_get_fd (pipewire_source->pipewire_loop),
+                        G_IO_IN | G_IO_ERR);
+
+  pw_loop_enter (pipewire_source->pipewire_loop);
+  g_source_attach (&pipewire_source->base, NULL);
+
+  return g_steal_pointer (&pipewire_source);
+}
+
+static void
+pipewire_source_unref (GrdPipeWireSource *pipewire_source)
+{
+  g_source_unref (&pipewire_source->base);
+}
 
 gboolean
 grd_pipewire_buffer_has_pointer_bitmap (struct pw_buffer *buffer)
diff --git a/src/grd-pipewire-utils.h b/src/grd-pipewire-utils.h
index 67553258..52b7623c 100644
--- a/src/grd-pipewire-utils.h
+++ b/src/grd-pipewire-utils.h
@@ -35,9 +35,13 @@ typedef struct _GrdPipeWireSource
 {
   GSource base;
 
+  char *message_tag;
   struct pw_loop *pipewire_loop;
 } GrdPipeWireSource;
 
+GrdPipeWireSource *grd_attached_pipewire_source_new (const char  *message_tag,
+                                                     GError     **error);
+
 gboolean grd_pipewire_buffer_has_pointer_bitmap (struct pw_buffer *buffer);
 
 gboolean grd_pipewire_buffer_has_frame_data (struct pw_buffer *buffer);