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