From 47c57a5b87d9e46cb1b86e417a87e8141aa1682d Mon Sep 17 00:00:00 2001
From: LeRoyce Pearson <contact@leroycepearson.dev>
Date: Sat, 12 Aug 2023 17:28:33 -0600
Subject: [PATCH] Explicitly handle case where not all globals exist

---
 examples/01_client_connect.zig | 21 ++++++++++++++-------
 src/core.zig                   |  2 ++
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/examples/01_client_connect.zig b/examples/01_client_connect.zig
index 8d96c99..d8f49fe 100644
--- a/examples/01_client_connect.zig
+++ b/examples/01_client_connect.zig
@@ -31,9 +31,9 @@ pub fn main() !void {
         try socket.writeAll(std.mem.sliceAsBytes(message));
     }
 
-    var shm_id: u32 = id_pool.create();
-    var compositor_id: u32 = id_pool.create();
-    var xdg_wm_base_id: u32 = id_pool.create();
+    var shm_id_opt: ?u32 = null;
+    var compositor_id_opt: ?u32 = null;
+    var xdg_wm_base_id_opt: ?u32 = null;
 
     var message_buffer = std.ArrayList(u32).init(gpa);
     defer message_buffer.deinit();
@@ -54,6 +54,7 @@ pub fn main() !void {
                 .global => |global| {
                     var buffer: [20]u32 = undefined;
                     if (std.mem.eql(u8, global.interface, "wl_shm")) {
+                        shm_id_opt = id_pool.create();
                         const message = try wayland.serialize(
                             wayland.core.Registry.Request,
                             &buffer,
@@ -62,11 +63,12 @@ pub fn main() !void {
                                 .name = global.name,
                                 .interface = global.interface,
                                 .version = global.version,
-                                .new_id = shm_id,
+                                .new_id = shm_id_opt.?,
                             } },
                         );
                         try socket.writeAll(std.mem.sliceAsBytes(message));
-                    } else if (std.mem.eql(u8, global.interface, "wl_compositor")) {
+                    } else if (std.mem.eql(u8, global.interface, wayland.core.Compositor.INTERFACE)) {
+                        compositor_id_opt = id_pool.create();
                         const message = try wayland.serialize(
                             wayland.core.Registry.Request,
                             &buffer,
@@ -75,11 +77,12 @@ pub fn main() !void {
                                 .name = global.name,
                                 .interface = global.interface,
                                 .version = global.version,
-                                .new_id = compositor_id,
+                                .new_id = compositor_id_opt.?,
                             } },
                         );
                         try socket.writeAll(std.mem.sliceAsBytes(message));
                     } else if (std.mem.eql(u8, global.interface, "xdg_wm_base")) {
+                        xdg_wm_base_id_opt = id_pool.create();
                         const message = try wayland.serialize(
                             wayland.core.Registry.Request,
                             &buffer,
@@ -88,7 +91,7 @@ pub fn main() !void {
                                 .name = global.name,
                                 .interface = global.interface,
                                 .version = global.version,
-                                .new_id = xdg_wm_base_id,
+                                .new_id = xdg_wm_base_id_opt.?,
                             } },
                         );
                         try socket.writeAll(std.mem.sliceAsBytes(message));
@@ -103,6 +106,10 @@ pub fn main() !void {
         }
     }
 
+    const shm_id = shm_id_opt orelse return error.NeccessaryWaylandExtensionMissing;
+    const compositor_id = compositor_id_opt orelse return error.NeccessaryWaylandExtensionMissing;
+    const xdg_wm_base_id = xdg_wm_base_id_opt orelse return error.NeccessaryWaylandExtensionMissing;
+
     const surface_id = id_pool.create();
     {
         var buffer: [10]u32 = undefined;
diff --git a/src/core.zig b/src/core.zig
index 9e0857d..0fed8cf 100644
--- a/src/core.zig
+++ b/src/core.zig
@@ -85,6 +85,8 @@ pub const Registry = struct {
 };
 
 pub const Compositor = struct {
+    pub const INTERFACE = "wl_compositor";
+
     pub const Request = union(Request.Tag) {
         create_surface: CreateSurface,
         create_region: CreateRegion,