[mutter] renderer: Add API to get a view list for a monitor

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit feb444402eb3e4e2ae6ed35015448ce17d534e8a
Author: Jonas Ådahl <jadahl gmail com>
Date:   Wed Apr 1 11:14:46 2020 +0200

    renderer: Add API to get a view list for a monitor
    
    Where renderer views correspond to CRTCs, this will result in a list of
    those views; otherwise (i.e. X11 CM), it'll result in a list containing
    the global view.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1285

 src/backends/meta-renderer.c               | 70 ++++++++++++++++++++++++++++++
 src/backends/meta-renderer.h               |  5 +++
 src/backends/x11/cm/meta-renderer-x11-cm.c |  9 ++++
 3 files changed, 84 insertions(+)
---
diff --git a/src/backends/meta-renderer.c b/src/backends/meta-renderer.c
index e0107ec9d6..919354d44c 100644
--- a/src/backends/meta-renderer.c
+++ b/src/backends/meta-renderer.c
@@ -172,6 +172,75 @@ meta_renderer_real_rebuild_views (MetaRenderer *renderer)
     }
 }
 
+static MetaRendererView *
+meta_renderer_get_view_for_crtc (MetaRenderer *renderer,
+                                 MetaCrtc     *crtc)
+{
+  MetaRendererPrivate *priv = meta_renderer_get_instance_private (renderer);
+  GList *l;
+
+  for (l = priv->views; l; l = l->next)
+    {
+      MetaRendererView *view = l->data;
+
+      if (meta_renderer_view_get_crtc (view) == crtc)
+        return view;
+    }
+
+  return NULL;
+}
+
+typedef struct _CollectViewsData
+{
+  MetaRenderer *renderer;
+  GList *out_views;
+} CollectViewsData;
+
+static gboolean
+collect_views (MetaMonitor          *monitor,
+               MetaMonitorMode      *mode,
+               MetaMonitorCrtcMode  *monitor_crtc_mode,
+               gpointer              user_data,
+               GError              **error)
+{
+  CollectViewsData *data = user_data;
+  MetaCrtc *crtc;
+  MetaRendererView *view;
+
+  crtc = meta_output_get_assigned_crtc (monitor_crtc_mode->output);
+  view = meta_renderer_get_view_for_crtc (data->renderer, crtc);
+  if (!g_list_find (data->out_views, view))
+    data->out_views = g_list_prepend (data->out_views, view);
+
+  return TRUE;
+}
+
+static GList *
+meta_renderer_real_get_views_for_monitor (MetaRenderer *renderer,
+                                          MetaMonitor  *monitor)
+{
+  CollectViewsData data = { 0 };
+  MetaMonitorMode *monitor_mode;
+
+  data.renderer = renderer;
+
+  monitor_mode = meta_monitor_get_current_mode (monitor);
+  meta_monitor_mode_foreach_crtc (monitor, monitor_mode,
+                                  collect_views,
+                                  &data,
+                                  NULL);
+
+  return data.out_views;
+}
+
+GList *
+meta_renderer_get_views_for_monitor (MetaRenderer *renderer,
+                                     MetaMonitor  *monitor)
+{
+  return META_RENDERER_GET_CLASS (renderer)->get_views_for_monitor (renderer,
+                                                                    monitor);
+}
+
 void
 meta_renderer_add_view (MetaRenderer     *renderer,
                         MetaRendererView *view)
@@ -278,6 +347,7 @@ meta_renderer_class_init (MetaRendererClass *klass)
   object_class->finalize = meta_renderer_finalize;
 
   klass->rebuild_views = meta_renderer_real_rebuild_views;
+  klass->get_views_for_monitor = meta_renderer_real_get_views_for_monitor;
 
   obj_props[PROP_BACKEND] =
     g_param_spec_object ("backend",
diff --git a/src/backends/meta-renderer.h b/src/backends/meta-renderer.h
index 247d2c2aae..278e645820 100644
--- a/src/backends/meta-renderer.h
+++ b/src/backends/meta-renderer.h
@@ -46,6 +46,8 @@ struct _MetaRendererClass
                                       MetaOutput         *output,
                                       MetaCrtc           *crtc);
   void (* rebuild_views) (MetaRenderer *renderer);
+  GList * (* get_views_for_monitor) (MetaRenderer *renderer,
+                                     MetaMonitor  *monitor);
 };
 
 MetaBackend * meta_renderer_get_backend (MetaRenderer *renderer);
@@ -57,6 +59,9 @@ void meta_renderer_rebuild_views (MetaRenderer *renderer);
 void meta_renderer_add_view (MetaRenderer     *renderer,
                              MetaRendererView *view);
 
+GList * meta_renderer_get_views_for_monitor (MetaRenderer *renderer,
+                                             MetaMonitor  *monitor);
+
 META_EXPORT_TEST
 GList * meta_renderer_get_views (MetaRenderer *renderer);
 
diff --git a/src/backends/x11/cm/meta-renderer-x11-cm.c b/src/backends/x11/cm/meta-renderer-x11-cm.c
index a288fe61f6..18ad5eb5d1 100644
--- a/src/backends/x11/cm/meta-renderer-x11-cm.c
+++ b/src/backends/x11/cm/meta-renderer-x11-cm.c
@@ -94,6 +94,13 @@ meta_renderer_x11_cm_rebuild_views (MetaRenderer *renderer)
   meta_renderer_add_view (renderer, renderer_x11_cm->screen_view);
 }
 
+static GList *
+meta_renderer_x11_cm_get_views_for_monitor (MetaRenderer *renderer,
+                                            MetaMonitor  *monitor)
+{
+  return g_list_prepend (NULL, meta_renderer_get_views (renderer)->data);
+}
+
 static void
 meta_renderer_x11_cm_init (MetaRendererX11Cm *renderer_x11_cm)
 {
@@ -105,4 +112,6 @@ meta_renderer_x11_cm_class_init (MetaRendererX11CmClass *klass)
   MetaRendererClass *renderer_class = META_RENDERER_CLASS (klass);
 
   renderer_class->rebuild_views = meta_renderer_x11_cm_rebuild_views;
+  renderer_class->get_views_for_monitor =
+    meta_renderer_x11_cm_get_views_for_monitor;
 }