Refactor xdg_shell handling

src/server.zig

@@ -11,8 +11,10 @@ pub const Server = struct {
 
     listen_new_output: c.wl_listener,
 
-    xdg_shell: *c.wlr_xdg_shell,
-    new_xdg_surface: c.wl_listener,
+    wlr_xdg_shell: *c.wlr_xdg_shell,
+    listen_new_xdg_surface: c.wl_listener,
+
+    // Must stay ordered bottom to top
     views: std.ArrayList(View),
 
     pub fn init(allocator: *std.mem.Allocator) !@This() {
@@ -57,6 +59,17 @@ pub const Server = struct {
         // Setup a listener for new outputs
         server.listen_new_output = handle_new_output;
         c.wl_signal_add(&server.wlr_backend.*.events.new_output, &server.listen_new_output);
+
+        // Set up our list of views and the xdg-shell. The xdg-shell is a Wayland
+        // protocol which is used for application windows.
+        // https://drewdevault.com/2018/07/29/Wayland-shells.html
+        server.views = std.ArrayList(View).init(std.heap.c_allocator);
+        server.wlr_xdg_shell = c.wlr_xdg_shell_create(server.wl_display) orelse
+            return error.CantCreateWlrXdgShell;
+        server.listen_new_xdg_surface.notify = handle_new_xdg_surface;
+        c.wl_signal_add(&server.xdg_shell.*.events.new_surface, &server.listen_new_xdg_surface);
+
+        return server;
     }
 
     /// Free allocated memory and clean up
@@ -120,6 +133,31 @@ pub const Server = struct {
         var wlr_output = @ptrCast(*c.wlr_output, @alignCast(@alignOf(*c.wlr_output), data));
 
         // TODO: Handle failure
-        server.outputs.append(Output.init(server, wlr_output) orelse return);
+        server.outputs.append(Output.init(server, wlr_output) catch unreachable);
+    }
+
+    fn handle_new_xdg_surface(listener: [*c]c.wl_listener, data: ?*c_void) callconv(.C) void {
+        // This event is raised when wlr_xdg_shell receives a new xdg surface from a
+        // client, either a toplevel (application window) or popup.
+        var server = @fieldParentPtr(Server, "listen_new_xdg_surface", listener);
+        var wlr_xdg_surface = @ptrCast(*c.wlr_xdg_surface, @alignCast(@alignOf(*c.wlr_xdg_surface), data));
+
+        if (wlr_xdg_surface.role != c.enum_wlr_xdg_surface_role.WLR_XDG_SURFACE_ROLE_TOPLEVEL) {
+            return;
+        }
+
+        // Init a View to handle this surface
+        server.*.views.append(View.init(server, wlr_xdg_surface)) catch unreachable;
+    }
+
+    /// Finds the top most view under the output layout coordinates lx, ly
+    /// returns the view if found, and a pointer to the wlr_surface as well as the surface coordinates
+    pub fn desktop_view_at(self: *@This(), lx: f64, ly: f64, surface: *?*c.wlr_surface, sx: *f64, sy: *f64) ?*View {
+        for (server.*.views.span()) |*view| {
+            if (view.is_at(lx, ly, surface, sx, sy)) {
+                return view;
+            }
+        }
+        return null;
     }
 };