OLD | NEW |
(Empty) | |
| 1 // Copyright 2017 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/generic_sensor/public/cpp/sensor_shared_buffer_reader.h" |
| 6 |
| 7 #include "device/base/synchronization/shared_memory_seqlock_buffer.h" |
| 8 #include "device/generic_sensor/public/cpp/sensor_reading.h" |
| 9 |
| 10 namespace { |
| 11 |
| 12 constexpr int kMaxReadAttemptsCount = 10; |
| 13 |
| 14 } // namespace |
| 15 |
| 16 namespace device { |
| 17 |
| 18 SensorSharedBufferReader::SensorSharedBufferReader( |
| 19 const SensorReadingSharedBuffer* buffer) |
| 20 : buffer_(buffer) {} |
| 21 |
| 22 SensorSharedBufferReader::~SensorSharedBufferReader() = default; |
| 23 |
| 24 bool SensorSharedBufferReader::GetSensorReading(SensorReading* result) { |
| 25 int read_attempts = 0; |
| 26 while (!TryReadFromBuffer(result)) { |
| 27 if (++read_attempts == kMaxReadAttemptsCount) |
| 28 return false; |
| 29 } |
| 30 |
| 31 return true; |
| 32 } |
| 33 |
| 34 bool SensorSharedBufferReader::TryReadFromBuffer(SensorReading* result) { |
| 35 const OneWriterSeqLock& seqlock = buffer_->seqlock.value(); |
| 36 auto version = seqlock.ReadBegin(); |
| 37 auto reading_data = buffer_->reading; |
| 38 if (seqlock.ReadRetry(version)) |
| 39 return false; |
| 40 *result = reading_data; |
| 41 return true; |
| 42 } |
| 43 |
| 44 } // namespace device |
OLD | NEW |