content/browser/device_orientation/device_inertial_sensor_service.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 "content/browser/device_orientation/device_inertial_sensor_service.h"
   6
   7 #include "base/bind.h"
   8 #include "base/logging.h"
   9 #include "base/memory/singleton.h"
  10 #include "content/browser/device_orientation/data_fetcher_shared_memory.h"
  11 #include "content/public/browser/render_process_host.h"
  12
  13 namespace content {
  14
  15 DeviceInertialSensorService::DeviceInertialSensorService()
  16     : num_motion_readers_(0),
  17       num_orientation_readers_(0),
  18       is_shutdown_(false) {
  19 }
  20
  21 DeviceInertialSensorService::~DeviceInertialSensorService() {
  22 }
  23
  24 DeviceInertialSensorService* DeviceInertialSensorService::GetInstance() {
  25   return Singleton<DeviceInertialSensorService,
  26                    LeakySingletonTraits<DeviceInertialSensorService> >::get();
  27 }
  28
  29 void DeviceInertialSensorService::AddConsumer(ConsumerType consumer_type) {
  30   if (!ChangeNumberConsumers(consumer_type, 1))
  31     return;
  32
  33   DCHECK(GetNumberConsumers(consumer_type));
  34
  35   if (!data_fetcher_)
  36     data_fetcher_.reset(new DataFetcherSharedMemory);
  37   data_fetcher_->StartFetchingDeviceData(consumer_type);
  38 }
  39
  40 void DeviceInertialSensorService::RemoveConsumer(ConsumerType consumer_type) {
  41   if (!ChangeNumberConsumers(consumer_type, -1))
  42     return;
  43
  44   if (GetNumberConsumers(consumer_type) == 0)
  45     data_fetcher_->StopFetchingDeviceData(consumer_type);
  46 }
  47
  48 bool DeviceInertialSensorService::ChangeNumberConsumers(
  49     ConsumerType consumer_type, int delta) {
  50   DCHECK(thread_checker_.CalledOnValidThread());
  51   if (is_shutdown_)
  52     return false;
  53
  54   switch (consumer_type) {
  55     case CONSUMER_TYPE_MOTION:
  56       num_motion_readers_ += delta;
  57       DCHECK(num_motion_readers_ >= 0);
  58       return true;
  59     case CONSUMER_TYPE_ORIENTATION:
  60       num_orientation_readers_ += delta;
  61       DCHECK(num_orientation_readers_ >= 0);
  62       return true;
  63     default:
  64       NOTREACHED();
  65   }
  66   return false;
  67 }
  68
  69 int DeviceInertialSensorService::GetNumberConsumers(
  70     ConsumerType consumer_type) const {
  71   switch (consumer_type) {
  72     case CONSUMER_TYPE_MOTION:
  73       return num_motion_readers_;
  74     case CONSUMER_TYPE_ORIENTATION:
  75       return num_orientation_readers_;
  76     default:
  77       NOTREACHED();
  78   }
  79   return 0;
  80 }
  81
  82 base::SharedMemoryHandle
  83 DeviceInertialSensorService::GetSharedMemoryHandleForProcess(
  84     ConsumerType consumer_type, base::ProcessHandle handle) {
  85   DCHECK(thread_checker_.CalledOnValidThread());
  86   return data_fetcher_->GetSharedMemoryHandleForProcess(consumer_type, handle);
  87 }
  88
  89 void DeviceInertialSensorService::Shutdown() {
  90   data_fetcher_.reset();
  91   is_shutdown_ = true;
  92 }
  93
  94 void DeviceInertialSensorService::SetDataFetcherForTests(
  95     DataFetcherSharedMemory* test_data_fetcher) {
  96   data_fetcher_.reset(test_data_fetcher);
  97 }
  98
  99 }  // namespace content