wayland: Send edge constraints

Following up the previous patch, this patch makes the
Wayland backend send the edge constraints through a
custom protocol extension internal to GTK.

As it mature, we can think of upstreaming the protocol
to Wayland itself.

https://bugzilla.gnome.org/show_bug.cgi?id=751857

src/wayland/meta-wayland-gtk-shell.c

@@ -148,31 +148,124 @@ gtk_surface_surface_destroyed (MetaWaylandGtkSurface *gtk_surface)
 }
 
 static void
-fill_states (struct wl_array *states,
+fill_edge_states (struct wl_array *states,
                   MetaWindow      *window)
 {
   uint32_t *s;
 
-  if (window->tile_mode == META_TILE_LEFT ||
+  /* Top */
-      window->tile_mode == META_TILE_RIGHT)
+  if (window->edge_constraints[0] != META_EDGE_CONSTRAINT_MONITOR)
+    {
+      s = wl_array_add (states, sizeof *s);
+      *s = GTK_SURFACE1_EDGE_CONSTRAINT_RESIZABLE_TOP;
+    }
+
+  /* Right */
+  if (window->edge_constraints[1] != META_EDGE_CONSTRAINT_MONITOR)
+    {
+      s = wl_array_add (states, sizeof *s);
+      *s = GTK_SURFACE1_EDGE_CONSTRAINT_RESIZABLE_RIGHT;
+    }
+
+  /* Bottom */
+  if (window->edge_constraints[2] != META_EDGE_CONSTRAINT_MONITOR)
+    {
+      s = wl_array_add (states, sizeof *s);
+      *s = GTK_SURFACE1_EDGE_CONSTRAINT_RESIZABLE_BOTTOM;
+    }
+
+  /* Left */
+  if (window->edge_constraints[3] != META_EDGE_CONSTRAINT_MONITOR)
+    {
+      s = wl_array_add (states, sizeof *s);
+      *s = GTK_SURFACE1_EDGE_CONSTRAINT_RESIZABLE_LEFT;
+    }
+}
+
+static void
+send_configure_edges (MetaWaylandGtkSurface *gtk_surface,
+                      MetaWindow            *window)
+{
+  struct wl_array edge_states;
+
+  wl_array_init (&edge_states);
+  fill_edge_states (&edge_states, window);
+
+  gtk_surface1_send_configure_edges (gtk_surface->resource, &edge_states);
+
+  wl_array_release (&edge_states);
+}
+
+static void
+fill_states (struct wl_array    *states,
+             MetaWindow         *window,
+             struct wl_resource *resource)
+{
+  uint32_t *s;
+  guint version;
+
+  version = wl_resource_get_version (resource);
+
+  if (version < GTK_SURFACE1_CONFIGURE_EDGES_SINCE_VERSION &&
+      (window->tile_mode == META_TILE_LEFT ||
+       window->tile_mode == META_TILE_RIGHT))
     {
       s = wl_array_add (states, sizeof *s);
       *s = GTK_SURFACE1_STATE_TILED;
     }
+
+  if (version >= GTK_SURFACE1_STATE_TILED_TOP_SINCE_VERSION &&
+      window->edge_constraints[0] != META_EDGE_CONSTRAINT_NONE)
+    {
+      s = wl_array_add (states, sizeof *s);
+      *s = GTK_SURFACE1_STATE_TILED_TOP;
+    }
+
+  if (version >= GTK_SURFACE1_STATE_TILED_RIGHT_SINCE_VERSION &&
+      window->edge_constraints[1] != META_EDGE_CONSTRAINT_NONE)
+    {
+      s = wl_array_add (states, sizeof *s);
+      *s = GTK_SURFACE1_STATE_TILED_RIGHT;
+    }
+
+  if (version >= GTK_SURFACE1_STATE_TILED_BOTTOM_SINCE_VERSION &&
+      window->edge_constraints[2] != META_EDGE_CONSTRAINT_NONE)
+    {
+      s = wl_array_add (states, sizeof *s);
+      *s = GTK_SURFACE1_STATE_TILED_BOTTOM;
+    }
+
+  if (version >= GTK_SURFACE1_STATE_TILED_LEFT_SINCE_VERSION &&
+      window->edge_constraints[3] != META_EDGE_CONSTRAINT_NONE)
+    {
+      s = wl_array_add (states, sizeof *s);
+      *s = GTK_SURFACE1_STATE_TILED_LEFT;
+    }
+}
+
+static void
+send_configure (MetaWaylandGtkSurface *gtk_surface,
+                MetaWindow            *window)
+{
+  struct wl_array states;
+
+  wl_array_init (&states);
+  fill_states (&states, window, gtk_surface->resource);
+
+  gtk_surface1_send_configure (gtk_surface->resource, &states);
+
+  wl_array_release (&states);
 }
 
 static void
 on_configure (MetaWaylandSurface    *surface,
               MetaWaylandGtkSurface *gtk_surface)
 {
-  struct wl_array states;
+  send_configure (gtk_surface, surface->window);
 
-  wl_array_init (&states);
-  fill_states (&states, surface->window);
 
-  gtk_surface1_send_configure (gtk_surface->resource, &states);
+  if (wl_resource_get_version (gtk_surface->resource) >= GTK_SURFACE1_CONFIGURE_EDGES_SINCE_VERSION)
-
+    send_configure_edges (gtk_surface, surface->window);
-  wl_array_release (&states);
 }
 
 static void

src/wayland/meta-wayland-versions.h

@@ -42,7 +42,7 @@
 #define META_WL_SEAT_VERSION                5
 #define META_WL_OUTPUT_VERSION              2
 #define META_XSERVER_VERSION                1
-#define META_GTK_SHELL1_VERSION             1
+#define META_GTK_SHELL1_VERSION             2
 #define META_WL_SUBCOMPOSITOR_VERSION       1
 #define META_ZWP_POINTER_GESTURES_V1_VERSION    1
 #define META_ZXDG_EXPORTER_V1_VERSION       1

src/wayland/protocol/gtk-shell.xml

@@ -1,6 +1,6 @@
 <protocol name="gtk">
 
-  <interface name="gtk_shell1" version="1">
+  <interface name="gtk_shell1" version="2">
     <description summary="gtk specific extensions">
       gtk_shell is a protocol extension providing additional features for
       clients implementing it.
@@ -30,7 +30,7 @@
     </request>
   </interface>
 
-  <interface name="gtk_surface1" version="1">
+  <interface name="gtk_surface1" version="2">
     <request name="set_dbus_properties">
       <arg name="application_id" type="string" allow-null="true"/>
       <arg name="app_menu_path" type="string" allow-null="true"/>
@@ -51,11 +51,27 @@
 
     <enum name="state">
       <entry name="tiled" value="1"/>
+
+      <entry name="tiled_top" value="2" since="2" />
+      <entry name="tiled_right" value="3" since="2" />
+      <entry name="tiled_bottom" value="4" since="2" />
+      <entry name="tiled_left" value="5"  since="2" />
+    </enum>
+
+    <enum name="edge_constraint" since="2">
+      <entry name="resizable_top" value="1"/>
+      <entry name="resizable_right" value="2"/>
+      <entry name="resizable_bottom" value="3"/>
+      <entry name="resizable_left" value="4"/>
     </enum>
 
     <event name="configure">
       <arg name="states" type="array"/>
     </event>
+
+    <event name="configure_edges" since="2">
+      <arg name="constraints" type="array"/>
+    </event>
   </interface>
 
 </protocol>