Gamepad API support for chrome on android

content/browser/android/gamepad_reader_impl.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/android/gamepad_reader_impl.h"
+
+#include "base/android/jni_android.h"
+#include "base/android/jni_string.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
+#include "base/strings/utf_string_conversions.h"
+
+#include "jni/GamepadList_jni.h"
+
+using base::android::AttachCurrentThread;
+using base::android::CheckException;
+using base::android::ClearException;
+using base::android::ConvertJavaStringToUTF8;
+using base::android::ScopedJavaLocalRef;
+using blink::WebGamepad;
+using blink::WebGamepads;
+
+namespace content {
+
+bool GamepadsReader::RegisterGamepadsReader(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+GamepadsReader::GamepadsReader() {
+  JNIEnv* env = AttachCurrentThread();
+  CreateJavaObject(env);
+}
+
+GamepadsReader::~GamepadsReader() { CHECK(java_gamepadList_object_.is_null()); }
+
+GamepadsReader* GamepadsReader::GetInstance() {
+  return Singleton<GamepadsReader>::get();
+}
+
+void GamepadsReader::GetGamepadData(blink::WebGamepads* pads) {
+  JNIEnv* env = AttachCurrentThread();
+  if (!env)
+    return;
+
+  gamepads_data_ = pads;
+  Java_GamepadList_getGamepadData(env, java_gamepadList_object_.obj());
+}
+
+void GamepadsReader::UpdateDeviceCount(JNIEnv* env,
+                                       jobject obj,
+                                       int devicecount) {
+  gamepads_data_->length = devicecount;
+}
+
+void GamepadsReader::SetGamepadData(JNIEnv* env,
+                                    jobject obj,
+                                    int index,
+                                    bool connected,
+                                    jstring devicename,
+                                    int64 timestamp,
+                                    jfloatArray jaxes,
+                                    jfloatArray jbuttons) {
+
+  blink::WebGamepad& pad = gamepads_data_->items[index];
+  pad.connected = connected;
+
+  pad.timestamp = timestamp;
+
+  // Do not set gamepad parameters for all the gamepad devices that are not
+  // attached.
+  if (!connected)
+    return;
+
+  // Map the Gamepad DeviceName String to the WebGamepad Id. Ideally it should
+  // be mapped to vendor and product information but it is only available at
+  // kernel level and it can not be queried using class
+  // android.hardware.input.InputManager.
+
+  jsize device_name_length = env->GetStringLength(devicename);
+  const jchar* device_name_utf16 = env->GetStringChars(devicename, 0);
+  COMPILE_ASSERT(sizeof(jchar) == sizeof(blink::WebUChar),
+                 jchar_and_WebUChar_are_same_size);
+  const size_t bytes_to_copy =
+      std::min(device_name_length * sizeof(jchar), WebGamepad::idLengthCap);
+  memcpy(pad.id, device_name_utf16, bytes_to_copy);
+  pad.id[bytes_to_copy] = 0;
+  env->ReleaseStringChars(devicename, device_name_utf16);
+
+  pad.timestamp = timestamp;
+
+  // Set WebGamepad axeslength to total number of axes on the gamepad device.
+  // Only return the first axesLengthCap if axeslength captured by GamepadList
+  // is larger than axesLengthCap.
+
+  pad.axesLength = std::min(env->GetArrayLength(jaxes),
+                            static_cast<int>(WebGamepad::axesLengthCap));
+  jfloat* raw_axes = env->GetFloatArrayElements(jaxes, 0);
+  memcpy(pad.axes, raw_axes, pad.axesLength * sizeof(float));
+  env->ReleaseFloatArrayElements(jaxes, raw_axes, 0);
+
+  // Set WebGamepad buttonslength to total number of axes on the gamepad
+  // device. Only return the first buttonsLengthCap if axeslength captured by
+  // GamepadList is larger than buttonsLengthCap.
+
+  pad.buttonsLength = std::min(env->GetArrayLength(jbuttons),
+                               static_cast<int>(WebGamepad::buttonsLengthCap));
+  jfloat* raw_buttons = env->GetFloatArrayElements(jbuttons, 0);
+  memcpy(pad.buttons, raw_buttons, pad.buttonsLength * sizeof(float));

[bajones, 2014/02/28 23:56:11]

This needs to be rebased. The current code no longer uses a float array for
button state.

[SaurabhK, 2014/03/11 17:39:27]

On 2014/02/28 23:56:11, bajones wrote:

Done.

+  env->ReleaseFloatArrayElements(jbuttons, raw_buttons, 0);
+}
+
+void GamepadsReader::NotifyForGamepadsAccess(bool access_paused) {
+  JNIEnv* env = AttachCurrentThread();
+  if (!env)
+    return;
+
+  CHECK(!java_gamepadList_object_.is_null());
+  Java_GamepadList_notifyForGamepadsAccess(
+      env, java_gamepadList_object_.obj(), access_paused);
+}
+
+void GamepadsReader::CreateJavaObject(JNIEnv* env) {
+  // Create the Java GamepadsReader object and attach it with GamepadList
+  // object.
+  java_gamepadList_object_.Reset(
+      Java_GamepadList_getInstance(env, reinterpret_cast<intptr_t>(this)));
+  CHECK(!java_gamepadList_object_.is_null());
+}
+
+}  // namespace content