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 d67da96ef1fbac542ffe2cfb0186d8e7dbf3bb0c..fe1239efaddac5865fd9416867dd4efa3de51990 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 <gaming-input-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
@@ -41,6 +42,8 @@
 #include "base/strings/utf_string_conversions.h"
 #include "components/exo/buffer.h"
 #include "components/exo/display.h"
+#include "components/exo/gamepad.h"
+#include "components/exo/gamepad_delegate.h"
 #include "components/exo/keyboard.h"
 #include "components/exo/keyboard_delegate.h"
 #include "components/exo/notification_surface.h"
@@ -125,6 +128,10 @@ 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);
@@ -2734,6 +2741,82 @@ void bind_alpha_compositing(wl_client* client,
                                  data, nullptr);
 }
 
+////////////////////////////////////////////////////////////////////////////////
+// zwp_gamepad_v1:
+
+// Gamepad delegate class that forwards gamepad events to the client resource.
+class WaylandGamepadDelegate : public GamepadDelegate {
+ public:
+  explicit WaylandGamepadDelegate(wl_resource* gamepad_resource)
+      : gamepad_resource_(gamepad_resource) {}
+
+  // Overridden from GamepadDelegate:
+  void OnGamepadDestroying(Gamepad* gamepad) override { delete this; }
+
+  void OnStateChange(bool connected) override {
+    uint32_t status = connected ? ZWP_GAMEPAD_V1_GAMEPAD_STATE_ON
+                                : ZWP_GAMEPAD_V1_GAMEPAD_STATE_OFF;
+    zwp_gamepad_v1_send_state_change(gamepad_resource_, status);
+    wl_client_flush(client());
+  }
+  void OnAxis(int axis, double value) override {
+    zwp_gamepad_v1_send_axis(gamepad_resource_, NowInMilliseconds(), axis,
+                             wl_fixed_from_double(value));
+  }
+  void OnButton(int button, bool pressed, double value) override {
+    uint32_t state = pressed ? ZWP_GAMEPAD_V1_BUTTON_STATE_PRESSED
+                             : ZWP_GAMEPAD_V1_BUTTON_STATE_RELEASED;
+    zwp_gamepad_v1_send_button(gamepad_resource_, NowInMilliseconds(), button,
+                               state, wl_fixed_from_double(value));
+  }
+  void OnFrame() override {
+    zwp_gamepad_v1_send_frame(gamepad_resource_, NowInMilliseconds());
+    wl_client_flush(client());
+  }
+
+ private:
+  // The client who own this gamepad instance.
+  wl_client* client() const {
+    return wl_resource_get_client(gamepad_resource_);
+  }
+
+  // The gamepad resource associated with the gamepad.
+  wl_resource* const gamepad_resource_;
+
+  DISALLOW_COPY_AND_ASSIGN(WaylandGamepadDelegate);
+};
+
+void gamepad_destroy(wl_client* client, wl_resource* resource) {
+  wl_resource_destroy(resource);
+}
+
+const struct zwp_gamepad_v1_interface gamepad_implementation = {
+    gamepad_destroy};
+
+void gaming_input_get_gamepad(wl_client* client,
+                              wl_resource* resource,
+                              uint32_t id,
+                              wl_resource* seat) {
+  wl_resource* gamepad_resource = wl_resource_create(
+      client, &zwp_gamepad_v1_interface, wl_resource_get_version(resource), id);
+  auto gamepad = new Gamepad(0, new WaylandGamepadDelegate(gamepad_resource));
+  SetImplementation(gamepad_resource, &gamepad_implementation,
+                    base::WrapUnique(gamepad));
+}
+
+const struct zwp_gaming_input_v1_interface gaming_input_implementation = {
+    gaming_input_get_gamepad};
+
+void bing_gaming_input(wl_client* client,
+                       void* data,
+                       uint32_t version,
+                       uint32_t id) {
+  wl_resource* resource =
+      wl_resource_create(client, &zwp_gaming_input_v1_interface, version, id);
+  wl_resource_set_implementation(resource, &gaming_input_implementation, data,
+                                 nullptr);
+}
+
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -2772,6 +2855,8 @@ 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_gaming_input_v1_interface, 1,
+                   display_, bing_gaming_input);
 }
 
 Server::~Server() {}