From 177b548b156ce4b46ff331d7c10f1bf373bf9cf7 Mon Sep 17 00:00:00 2001
From: Drew DeVault <sir@cmpwn.com>
Date: Sun, 22 Apr 2018 18:57:45 +0200
Subject: [PATCH] Update layer shell with optional wl_output

---
 include/wlr/types/wlr_layer_shell.h      | 3 +++
 protocol/wlr-layer-shell-unstable-v1.xml | 6 +++++-
 types/wlr_layer_shell.c                  | 4 +++-
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/include/wlr/types/wlr_layer_shell.h b/include/wlr/types/wlr_layer_shell.h
index 1312e5683..79b3a4ea4 100644
--- a/include/wlr/types/wlr_layer_shell.h
+++ b/include/wlr/types/wlr_layer_shell.h
@@ -27,6 +27,9 @@ struct wlr_layer_shell {
 	struct wl_listener display_destroy;
 
 	struct {
+		 // struct wlr_layer_surface *
+		 // Note: the output may be NULL. In this case, it is your
+		 // responsibility to assign an output before returning.
 		struct wl_signal new_surface;
 	} events;
 
diff --git a/protocol/wlr-layer-shell-unstable-v1.xml b/protocol/wlr-layer-shell-unstable-v1.xml
index 3181c0bbf..6a5d5d35f 100644
--- a/protocol/wlr-layer-shell-unstable-v1.xml
+++ b/protocol/wlr-layer-shell-unstable-v1.xml
@@ -47,12 +47,16 @@
         or manipulate a buffer prior to the first layer_surface.configure call
         must also be treated as errors.
 
+        You may pass NULL for output to allow the compositor to decide which
+        output to use. Generally this will be the one that the user most
+        recently interacted with.
+
         Clients can specify a namespace that defines the purpose of the layer
         surface.
       </description>
       <arg name="id" type="new_id" interface="zwlr_layer_surface_v1"/>
       <arg name="surface" type="object" interface="wl_surface"/>
-      <arg name="output" type="object" interface="wl_output"/>
+      <arg name="output" type="object" interface="wl_output" allow-null="true"/>
       <arg name="layer" type="uint" enum="layer" summary="layer to add this surface to"/>
       <arg name="namespace" type="string" summary="namespace for the layer surface"/>
     </request>
diff --git a/types/wlr_layer_shell.c b/types/wlr_layer_shell.c
index c4e39a173..78aa25366 100644
--- a/types/wlr_layer_shell.c
+++ b/types/wlr_layer_shell.c
@@ -319,7 +319,9 @@ static void layer_shell_handle_get_layer_surface(struct wl_client *wl_client,
 
 	surface->shell = shell;
 	surface->surface = wlr_surface;
-	surface->output = wlr_output_from_resource(output_resource);
+	if (output_resource) {
+		surface->output = wlr_output_from_resource(output_resource);
+	}
 	surface->resource = wl_resource_create(wl_client,
 		&zwlr_layer_surface_v1_interface,
 		wl_resource_get_version(client_resource),