Gamepad API for Android

content/browser/gamepad/gamepad_platform_data_fetcher_android.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/browser/gamepad/gamepad_platform_data_fetcher_android.h"
+
+#include "base/android/jni_array.h"
+#include "base/android/jni_string.h"
+#include "base/debug/trace_event.h"
+#include "base/strings/string16.h"
+#include "jni/GamepadAdapter_jni.h"
+#include "third_party/WebKit/public/platform/WebGamepad.h"
+
+using base::android::AttachCurrentThread;
+using base::string16;
+using blink::WebGamepad;
+using blink::WebGamepads;
+
+namespace content {
+
+namespace {
+
+template <size_t array_length>
+void CopyJavaStringToWebUCharArray(
+    JNIEnv* env, jstring src, blink::WebUChar* array) {
+  COMPILE_ASSERT(sizeof(string16::value_type) == sizeof(blink::WebUChar),
+                 string16_and_WebUChar_are_same_size);
+  string16 data;
+  base::android::ConvertJavaStringToUTF16(env, src, &data);
+  COMPILE_ASSERT(array_length > 0, array_length_at_least_1);
+  const size_t characters_to_copy = std::min(data.size(), array_length - 1);
+  memcpy(array, data.data(), characters_to_copy * sizeof(string16::value_type));
+  array[characters_to_copy] = 0;
+}
+
+}
+
+static void RefreshGamepad(
+    JNIEnv* env,
+    jobject obj,
+    jlong gamepads,
+    jint index,
+    jboolean connected,
+    jstring id,
+    jstring mapping,
+    jlong timestamp,
+    jfloatArray axes,
+    jfloatArray buttons) {
+  WebGamepad& pad = reinterpret_cast<WebGamepads*>(gamepads)->items[index];
+  pad.connected = connected;
+  if (!connected)
+    return;
+
+  CopyJavaStringToWebUCharArray<WebGamepad::idLengthCap>(env, id, pad.id);
+  CopyJavaStringToWebUCharArray<WebGamepad::mappingLengthCap>(
+      env, mapping, pad.mapping);
+
+  pad.timestamp = timestamp;
+
+  std::vector<float> axes_data;
+  base::android::JavaFloatArrayToFloatVector(env, axes, &axes_data);
+  pad.axesLength = std::min(axes_data.size(), WebGamepad::axesLengthCap);
+  memcpy(pad.axes, axes_data.begin(), pad.axesLength * sizeof(float));
+
+  std::vector<float> buttons_data;
+  base::android::JavaFloatArrayToFloatVector(env, buttons, &buttons_data);
+  pad.buttonsLength =
+      std::min(buttons_data.size(), WebGamepad::buttonsLengthCap);
+  for (unsigned i = 0; i < pad.buttonsLength; ++i) {
+    float value = buttons_data[i];
+    pad.buttons[i].pressed = value;
+    pad.buttons[i].value = value;
+  }
+}
+
+GamepadPlatformDataFetcherAndroid::GamepadPlatformDataFetcherAndroid() {
+  Java_GamepadAdapter_setDataRequested(AttachCurrentThread(), true);
+}
+
+GamepadPlatformDataFetcherAndroid::~GamepadPlatformDataFetcherAndroid() {
+}
+
+void GamepadPlatformDataFetcherAndroid::GetGamepadData(
+    WebGamepads* pads,
+    bool devices_changed_hint) {
+  TRACE_EVENT0("GAMEPAD", "GetGamepadData");
+  pads->length = WebGamepads::itemsLengthCap;
+  Java_GamepadAdapter_getGamepadData(
+      AttachCurrentThread(), reinterpret_cast<intptr_t>(pads));
+}
+
+void GamepadPlatformDataFetcherAndroid::PauseHint(bool paused) {
+  Java_GamepadAdapter_setDataRequested(AttachCurrentThread(), !paused);
+}
+
+bool GamepadPlatformDataFetcherAndroid::RegisterGamepadAdapter(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+}