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,
+                                    jstring mapping,
+                                    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.
+
+  base::string16 device_name;
+  base::android::ConvertJavaStringToUTF16(env, devicename, &device_name);
+  const size_t name_to_copy =
+      std::min(device_name.size(), WebGamepad::idLengthCap - 1);
+  memcpy(pad.id, device_name.data(), name_to_copy);
+  pad.id[name_to_copy] = 0;
+  pad.id[name_to_copy] = 0;

[jdduke (slow), 2014/03/18 09:43:15]

Looks like we have an extra assignment here, also below. with pad.mapping.

[SaurabhK, 2014/03/18 12:45:30]

On 2014/03/18 09:43:15, jdduke wrote:

Oh yes, some how i missed it. Removing in next patchset.

+
+  base::string16 mapping_name;
+  base::android::ConvertJavaStringToUTF16(env, devicename, &mapping_name);
+  const size_t mapping_to_copy =
+      std::min(mapping_name.size(), WebGamepad::mappingLengthCap - 1);
+  memcpy(pad.mapping, mapping_name.data(), mapping_to_copy);
+  pad.mapping[mapping_to_copy] = 0;
+  pad.mapping[mapping_to_copy] = 0;
+
+  pad.timestamp = timestamp;
+
+  std::vector<float> axes;
+  base::android::JavaFloatArrayToFloatVector(env, jaxes, &axes);
+
+  // 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 = (axes.size() > WebGamepad::axesLengthCap)

[jdduke (slow), 2014/03/18 09:43:15]

Why not std::min?

[SaurabhK, 2014/03/18 12:45:30]

On 2014/03/18 09:43:15, jdduke wrote:

Using it now in next patchset.

+                       ? WebGamepad::axesLengthCap
+                       : axes.size();
+  memcpy(pad.axes, axes.begin(), pad.axesLength * sizeof(float));
+
+  std::vector<float> buttons;
+  base::android::JavaFloatArrayToFloatVector(env, jbuttons, &buttons);
+
+  // 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 = (buttons.size() > WebGamepad::buttonsLengthCap)

[jdduke (slow), 2014/03/18 09:43:15]

Also std::min.

[SaurabhK, 2014/03/18 12:45:30]

On 2014/03/18 09:43:15, jdduke wrote:

Chainging in next patch-set.

+                          ? WebGamepad::buttonsLengthCap
+                          : buttons.size();
+  // Copy buttons state to the WebGamepad buttons[].
+  for (unsigned int j = 0; j < pad.buttonsLength; j++) {
+    pad.buttons[j].pressed = buttons[j];
+    pad.buttons[j].value = buttons[j];
+  }
+}
+
+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