content/renderer/device_orientation/device_orientation_event_pump.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "device_orientation_event_pump.h"
   6
   7 #include <cmath>
   8
   9 #include "content/common/device_orientation/device_orientation_messages.h"
  10 #include "content/public/renderer/render_thread.h"
  11 #include "third_party/WebKit/public/platform/WebDeviceOrientationListener.h"
  12
  13 namespace content {
  14
  15 const double DeviceOrientationEventPump::kOrientationThreshold = 0.1;
  16
  17 DeviceOrientationEventPump::DeviceOrientationEventPump()
  18     : DeviceSensorEventPump(), listener_(0) {
  19 }
  20
  21 DeviceOrientationEventPump::DeviceOrientationEventPump(int pump_delay_millis)
  22     : DeviceSensorEventPump(pump_delay_millis), listener_(0) {
  23 }
  24
  25 DeviceOrientationEventPump::~DeviceOrientationEventPump() {
  26 }
  27
  28 bool DeviceOrientationEventPump::SetListener(
  29     WebKit::WebDeviceOrientationListener* listener) {
  30   listener_ = listener;
  31   return listener_ ? RequestStart() : Stop();
  32 }
  33
  34 bool DeviceOrientationEventPump::OnControlMessageReceived(
  35     const IPC::Message& message) {
  36   bool handled = true;
  37   IPC_BEGIN_MESSAGE_MAP(DeviceOrientationEventPump, message)
  38     IPC_MESSAGE_HANDLER(DeviceOrientationMsg_DidStartPolling, OnDidStart)
  39     IPC_MESSAGE_UNHANDLED(handled = false)
  40   IPC_END_MESSAGE_MAP()
  41   return handled;
  42 }
  43
  44 void DeviceOrientationEventPump::FireEvent() {
  45   DCHECK(listener_);
  46   WebKit::WebDeviceOrientationData data;
  47   if (reader_->GetLatestData(&data) && ShouldFireEvent(data)) {
  48     memcpy(&data_, &data, sizeof(data));
  49     listener_->didChangeDeviceOrientation(data);
  50   }
  51 }
  52
  53 static bool IsSignificantlyDifferent(bool hasAngle1, double angle1,
  54     bool hasAngle2, double angle2) {
  55   if (hasAngle1 != hasAngle2)
  56     return true;
  57   return (hasAngle1 && std::fabs(angle1 - angle2) >=
  58           DeviceOrientationEventPump::kOrientationThreshold);
  59 }
  60
  61 bool DeviceOrientationEventPump::ShouldFireEvent(
  62     const WebKit::WebDeviceOrientationData& data) const {
  63   return data.allAvailableSensorsAreActive &&
  64       (IsSignificantlyDifferent(
  65           data_.hasAlpha, data_.alpha, data.hasAlpha, data.alpha) ||
  66        IsSignificantlyDifferent(
  67           data_.hasBeta, data_.beta, data.hasBeta, data.beta) ||
  68        IsSignificantlyDifferent(
  69           data_.hasGamma, data_.gamma, data.hasGamma, data.gamma));
  70 }
  71
  72 bool DeviceOrientationEventPump::InitializeReader(
  73     base::SharedMemoryHandle handle) {
  74   memset(&data_, 0, sizeof(data_));
  75   if (!reader_)
  76     reader_.reset(new DeviceOrientationSharedMemoryReader());
  77   return reader_->Initialize(handle);
  78 }
  79
  80 bool DeviceOrientationEventPump::SendStartMessage() {
  81   return RenderThread::Get()->Send(new DeviceOrientationHostMsg_StartPolling());
  82 }
  83
  84 bool DeviceOrientationEventPump::SendStopMessage() {
  85   return RenderThread::Get()->Send(new DeviceOrientationHostMsg_StopPolling());
  86 }
  87
  88 }  // namespace content