exo: Implement wayland gamepad support

components/exo/wayland/server.cc

Index: components/exo/wayland/server.cc
diff --git a/components/exo/wayland/server.cc b/components/exo/wayland/server.cc
index 3ef44e26282a37b0b7e43390de97f75b241e4917..4f45afd69677a91119271f9db59f05c472a02a73 100644
--- a/components/exo/wayland/server.cc
+++ b/components/exo/wayland/server.cc
@@ -14,6 +14,7 @@
 
 // Note: core wayland headers need to be included before protocol headers.
 #include <alpha-compositing-unstable-v1-server-protocol.h>  // NOLINT
+#include <gamepads-unstable-v1-server-protocol.h>           // NOLINT
 #include <remote-shell-unstable-v1-server-protocol.h>       // NOLINT
 #include <secure-output-unstable-v1-server-protocol.h>      // NOLINT
 #include <xdg-shell-unstable-v5-server-protocol.h>          // NOLINT
@@ -40,6 +41,8 @@
 #include "base/strings/utf_string_conversions.h"
 #include "components/exo/buffer.h"
 #include "components/exo/display.h"
+#include "components/exo/gamepads.h"
+#include "components/exo/gamepads_delegate.h"
 #include "components/exo/keyboard.h"
 #include "components/exo/keyboard_delegate.h"
 #include "components/exo/pointer.h"
@@ -122,6 +125,10 @@ uint32_t TimeTicksToMilliseconds(base::TimeTicks ticks) {
   return (ticks - base::TimeTicks()).InMilliseconds();
 }
 
+uint32_t NowInMilliseconds() {
+  return TimeTicksToMilliseconds(base::TimeTicks::Now());
+}
+
 // A property key containing the surface resource that is associated with
 // window. If unset, no surface resource is associated with window.
 DEFINE_SURFACE_PROPERTY_KEY(wl_resource*, kSurfaceResourceKey, nullptr);
@@ -2663,6 +2670,70 @@ void bind_alpha_compositing(wl_client* client,
                                  data, nullptr);
 }
 
+////////////////////////////////////////////////////////////////////////////////
+// zwp_gamepads_v1:
+
+// Gamepads delegate class that forwards gamepad events to the client resource.
+class WaylandGamepadsDelegate : public GamepadsDelegate {
+ public:
+  explicit WaylandGamepadsDelegate(wl_resource* gamepads_resource)
+      : gamepads_resource_(gamepads_resource) {}
+
+  // Overridden from GamepadsDelegate:
+  void OnGamepadsDestroying(Gamepads* gamepads) override { delete this; }
+
+  void OnConnected(int id) override {
+    zwp_gamepads_v1_send_connected(gamepads_resource_, id);
+    wl_client_flush(client());
+  }
+  void OnDisconnected(int id) override {
+    zwp_gamepads_v1_send_disconnected(gamepads_resource_, id);
+    wl_client_flush(client());
+  }
+  void OnAxis(int id, int axis, double value) override {
+    zwp_gamepads_v1_send_axis(gamepads_resource_, NowInMilliseconds(), id,
+                              axis, wl_fixed_from_double(value));
+  }
+  void OnButton(int id, int button, bool pressed, double value) override {
+    zwp_gamepads_v1_send_button(gamepads_resource_, NowInMilliseconds(), id,
+                                button, pressed, wl_fixed_from_double(value));
+  }
+  void OnFrame(int id) override {
+    zwp_gamepads_v1_send_frame(gamepads_resource_, NowInMilliseconds(), id);
+    wl_client_flush(client());
+  }
+
+ private:
+  // The client who own this gamepads instance.
+  wl_client* client() const {
+    return wl_resource_get_client(gamepads_resource_);
+  }
+
+  // The gamepads resource associated with the gamepads.
+  wl_resource* const gamepads_resource_;
+
+  DISALLOW_COPY_AND_ASSIGN(WaylandGamepadsDelegate);
+};
+
+void gamepads_destroy(wl_client* client, wl_resource* resource) {
+  wl_resource_destroy(resource);
+}
+
+const struct zwp_gamepads_v1_interface gamepads_implementation = {
+    gamepads_destroy};
+
+void bind_gamepads(wl_client* client,
+                   void* data,
+                   uint32_t version,
+                   uint32_t id) {
+  wl_resource* resource =
+      wl_resource_create(client, &zwp_gamepads_v1_interface, version, id);
+
+  auto gamepads = new Gamepads(new WaylandGamepadsDelegate(resource));
+  SetImplementation(resource, &gamepads_implementation,
+                    base::WrapUnique(gamepads));
+}
+
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -2701,6 +2772,8 @@ Server::Server(Display* display)
                    display_, bind_alpha_compositing);
   wl_global_create(wl_display_.get(), &zwp_remote_shell_v1_interface,
                    remote_shell_version, display_, bind_remote_shell);
+  wl_global_create(wl_display_.get(), &zwp_gamepads_v1_interface, 1, display_,
+                   bind_gamepads);
 }
 
 Server::~Server() {}