content/renderer/device_sensors/device_light_event_pump.cc

   1 // Copyright 2014 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 "content/renderer/device_sensors/device_light_event_pump.h"
   6
   7 #include "base/time/time.h"
   8 #include "content/common/device_sensors/device_light_messages.h"
   9 #include "content/public/renderer/render_thread.h"
  10 #include "third_party/WebKit/public/platform/WebDeviceLightListener.h"
  11
  12 namespace {
  13 // Default rate for firing of DeviceLight events.
  14 const int kDefaultLightPumpFrequencyHz = 5;
  15 const int kDefaultLightPumpDelayMicroseconds =
  16     base::Time::kMicrosecondsPerSecond / kDefaultLightPumpFrequencyHz;
  17 }  // namespace
  18
  19 namespace content {
  20
  21 DeviceLightEventPump::DeviceLightEventPump(RenderThread* thread)
  22     : DeviceSensorEventPump<blink::WebDeviceLightListener>(thread),
  23       last_seen_data_(-1) {
  24   pump_delay_microseconds_ = kDefaultLightPumpDelayMicroseconds;
  25 }
  26
  27 DeviceLightEventPump::~DeviceLightEventPump() {
  28 }
  29
  30 bool DeviceLightEventPump::OnControlMessageReceived(
  31     const IPC::Message& message) {
  32   bool handled = true;
  33   IPC_BEGIN_MESSAGE_MAP(DeviceLightEventPump, message)
  34     IPC_MESSAGE_HANDLER(DeviceLightMsg_DidStartPolling, OnDidStart)
  35     IPC_MESSAGE_UNHANDLED(handled = false)
  36   IPC_END_MESSAGE_MAP()
  37   return handled;
  38 }
  39
  40 void DeviceLightEventPump::FireEvent() {
  41   DCHECK(listener());
  42   DeviceLightData data;
  43   if (reader_->GetLatestData(&data) && ShouldFireEvent(data.value)) {
  44     last_seen_data_ = data.value;
  45     listener()->didChangeDeviceLight(data.value);
  46   }
  47 }
  48
  49 bool DeviceLightEventPump::ShouldFireEvent(double lux) const {
  50   if (lux < 0)
  51     return false;
  52
  53   if (lux == std::numeric_limits<double>::infinity()) {
  54     // no sensor data can be provided, fire an Infinity event to Blink.
  55     return true;
  56   }
  57
  58   return lux != last_seen_data_;
  59 }
  60
  61 bool DeviceLightEventPump::InitializeReader(base::SharedMemoryHandle handle) {
  62   if (!reader_)
  63     reader_.reset(new DeviceLightSharedMemoryReader());
  64   return reader_->Initialize(handle);
  65 }
  66
  67 void DeviceLightEventPump::SendStartMessage() {
  68   RenderThread::Get()->Send(new DeviceLightHostMsg_StartPolling());
  69 }
  70
  71 void DeviceLightEventPump::SendStopMessage() {
  72   last_seen_data_ = -1;
  73   RenderThread::Get()->Send(new DeviceLightHostMsg_StopPolling());
  74 }
  75
  76 void DeviceLightEventPump::SendFakeDataForTesting(void* fake_data) {
  77   double data = *static_cast<double*>(fake_data);
  78
  79   listener()->didChangeDeviceLight(data);
  80 }
  81
  82 }  // namespace content