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      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
     99