wayland-outputs: Refactor event sending to ensure we're consistent

This makes us behave the same both on bind and when an output
changes. In particular, we were not sending scale and done events on
output changes. We were also unconditionally sending mode events on
output changes even though these should only be sent if there is an
actual mode change.

https://bugzilla.gnome.org/show_bug.cgi?id=766528

src/wayland/meta-wayland-outputs.c

@@ -53,6 +53,80 @@ output_resource_destroy (struct wl_resource *res)
   wayland_output->resources = g_list_remove (wayland_output->resources, res);
 }
 
+static inline enum wl_output_transform
+wl_output_transform_from_meta_monitor_transform (MetaMonitorTransform transform)
+{
+  /* The enums are the same. */
+  return (enum wl_output_transform) transform;
+}
+
+static void
+send_output_events (struct wl_resource *resource,
+                    MetaWaylandOutput  *wayland_output,
+                    MetaMonitorInfo    *monitor_info,
+                    gboolean            need_all_events)
+{
+  int version = wl_resource_get_version (resource);
+
+  MetaOutput *output = monitor_info->outputs[0];
+  enum wl_output_transform transform = wl_output_transform_from_meta_monitor_transform (output->crtc->transform);
+  guint mode_flags = WL_OUTPUT_MODE_CURRENT;
+
+  MetaMonitorInfo *old_monitor_info = wayland_output->monitor_info;
+  enum wl_output_transform old_transform = wayland_output->transform;
+  guint old_mode_flags = wayland_output->mode_flags;
+  gint old_scale = wayland_output->scale;
+
+  gboolean need_done = FALSE;
+
+  if (need_all_events ||
+      old_monitor_info->rect.x != monitor_info->rect.x ||
+      old_monitor_info->rect.y != monitor_info->rect.y ||
+      old_transform != transform)
+    {
+      wl_output_send_geometry (resource,
+                               (int)monitor_info->rect.x,
+                               (int)monitor_info->rect.y,
+                               monitor_info->width_mm,
+                               monitor_info->height_mm,
+                               output->subpixel_order,
+                               output->vendor,
+                               output->product,
+                               transform);
+      need_done = TRUE;
+    }
+
+  if (output->crtc->current_mode == output->preferred_mode)
+    mode_flags |= WL_OUTPUT_MODE_PREFERRED;
+
+  if (need_all_events ||
+      old_monitor_info->rect.width != monitor_info->rect.width ||
+      old_monitor_info->rect.height != monitor_info->rect.height ||
+      old_monitor_info->refresh_rate != monitor_info->refresh_rate ||
+      old_mode_flags != mode_flags)
+    {
+      wl_output_send_mode (resource,
+                           mode_flags,
+                           (int)monitor_info->rect.width,
+                           (int)monitor_info->rect.height,
+                           (int)(monitor_info->refresh_rate * 1000));
+      need_done = TRUE;
+    }
+
+  if (version >= WL_OUTPUT_SCALE_SINCE_VERSION)
+    {
+      if (need_all_events ||
+          old_scale != output->scale)
+        {
+          wl_output_send_scale (resource, output->scale);
+          need_done = TRUE;
+        }
+
+      if (need_done)
+        wl_output_send_done (resource);
+    }
+}
+
 static void
 bind_output (struct wl_client *client,
              void *data,
@@ -62,7 +136,6 @@ bind_output (struct wl_client *client,
   MetaWaylandOutput *wayland_output = data;
   MetaMonitorInfo *monitor_info = wayland_output->monitor_info;
   struct wl_resource *resource;
-  guint mode_flags;
   MetaOutput *output = monitor_info->outputs[0];
 
   resource = wl_resource_create (client, &wl_output_interface, version, id);
@@ -77,35 +150,7 @@ bind_output (struct wl_client *client,
                 monitor_info->rect.width, monitor_info->rect.height,
                 monitor_info->refresh_rate);
 
-  wl_output_send_geometry (resource,
+  send_output_events (resource, wayland_output, monitor_info, TRUE);
-                           (int)monitor_info->rect.x,
-                           (int)monitor_info->rect.y,
-                           monitor_info->width_mm,
-                           monitor_info->height_mm,
-                           /* Cogl values reflect XRandR values,
-                              and so does wayland */
-                           output->subpixel_order,
-                           output->vendor,
-                           output->product,
-                           output->crtc->transform);
-
-  g_assert (output->crtc->current_mode != NULL);
-
-  mode_flags = WL_OUTPUT_MODE_CURRENT;
-  if (output->crtc->current_mode == output->preferred_mode)
-    mode_flags |= WL_OUTPUT_MODE_PREFERRED;
-
-  wl_output_send_mode (resource,
-                       mode_flags,
-                       (int)monitor_info->rect.width,
-                       (int)monitor_info->rect.height,
-                       (int)(monitor_info->refresh_rate * 1000));
-
-  if (version >= WL_OUTPUT_SCALE_SINCE_VERSION)
-    wl_output_send_scale (resource, output->scale);
-
-  if (version >= WL_OUTPUT_DONE_SINCE_VERSION)
-    wl_output_send_done (resource);
 }
 
 static void
@@ -117,11 +162,19 @@ wayland_output_destroy_notify (gpointer data)
   g_object_unref (wayland_output);
 }
 
-static inline enum wl_output_transform
+static void
-wl_output_transform_from_meta_monitor_transform (MetaMonitorTransform transform)
+wayland_output_set_monitor_info (MetaWaylandOutput *wayland_output,
+                                 MetaMonitorInfo   *monitor_info)
 {
-  /* The enums are the same. */
+  MetaOutput *output = monitor_info->outputs[0];
-  return (enum wl_output_transform) transform;
+  enum wl_output_transform transform = wl_output_transform_from_meta_monitor_transform (output->crtc->transform);
+
+  wayland_output->monitor_info = monitor_info;
+  wayland_output->transform = transform;
+  wayland_output->mode_flags = WL_OUTPUT_MODE_CURRENT;
+  if (output->crtc->current_mode == output->preferred_mode)
+    wayland_output->mode_flags |= WL_OUTPUT_MODE_PREFERRED;
+  wayland_output->scale = output->scale;
 }
 
 static void
@@ -129,50 +182,21 @@ wayland_output_update_for_output (MetaWaylandOutput *wayland_output,
                                   MetaMonitorInfo *monitor_info)
 {
   GList *iter;
-  guint mode_flags;
-  MetaOutput *output = monitor_info->outputs[0];
-  enum wl_output_transform wl_transform = wl_output_transform_from_meta_monitor_transform (output->crtc->transform);
-
-  mode_flags = WL_OUTPUT_MODE_CURRENT;
-  if (output->crtc->current_mode == output->preferred_mode)
-    mode_flags |= WL_OUTPUT_MODE_PREFERRED;
 
   for (iter = wayland_output->resources; iter; iter = iter->next)
     {
       struct wl_resource *resource = iter->data;
-
+      send_output_events (resource, wayland_output, monitor_info, FALSE);
-      if (wayland_output->x != monitor_info->rect.x ||
-          wayland_output->y != monitor_info->rect.y ||
-          wayland_output->transform != wl_transform)
-        {
-          wl_output_send_geometry (resource,
-                                   (int)monitor_info->rect.x,
-                                   (int)monitor_info->rect.y,
-                                   monitor_info->width_mm,
-                                   monitor_info->height_mm,
-                                   output->subpixel_order,
-                                   output->vendor,
-                                   output->product,
-                                   wl_transform);
-        }
-
-      wl_output_send_mode (resource,
-                           mode_flags,
-                           (int)monitor_info->rect.width,
-                           (int)monitor_info->rect.height,
-                           (int)(monitor_info->refresh_rate * 1000));
     }
 
   /* It's very important that we change the output pointer here, as
      the old structure is about to be freed by MetaMonitorManager */
-  wayland_output->monitor_info = monitor_info;
+  wayland_output_set_monitor_info (wayland_output, monitor_info);
-  wayland_output->x = monitor_info->rect.x;
-  wayland_output->y = monitor_info->rect.y;
-  wayland_output->transform = wl_transform;
 }
 
 static MetaWaylandOutput *
-meta_wayland_output_new (MetaWaylandCompositor *compositor)
+meta_wayland_output_new (MetaWaylandCompositor *compositor,
+                         MetaMonitorInfo *monitor_info)
 {
   MetaWaylandOutput *wayland_output;
 
@@ -181,6 +205,7 @@ meta_wayland_output_new (MetaWaylandCompositor *compositor)
                                              &wl_output_interface,
                                              META_WL_OUTPUT_VERSION,
                                              wayland_output, bind_output);
+  wayland_output_set_monitor_info (wayland_output, monitor_info);
 
   return wayland_output;
 }
@@ -211,7 +236,7 @@ meta_wayland_compositor_update_outputs (MetaWaylandCompositor *compositor,
           g_hash_table_steal (compositor->outputs, GSIZE_TO_POINTER (info->winsys_id));
         }
       else
-        wayland_output = meta_wayland_output_new (compositor);
+        wayland_output = meta_wayland_output_new (compositor, info);
 
       wayland_output_update_for_output (wayland_output, info);
       g_hash_table_insert (new_table, GSIZE_TO_POINTER (info->winsys_id), wayland_output);

src/wayland/meta-wayland-outputs.h

@@ -41,10 +41,11 @@ struct _MetaWaylandOutput
 {
   GObject                   parent;
 
-  MetaMonitorInfo          *monitor_info;
   struct wl_global         *global;
-  int                       x, y;
+  MetaMonitorInfo          *monitor_info;
   enum wl_output_transform  transform;
+  guint                     mode_flags;
+  gint                      scale;
 
   GList                    *resources;
 };