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/*
* Copyright 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "timer.h"
#include "message_loop_thread.h"
#include "time_util.h"
namespace bluetooth {
namespace common {
constexpr base::TimeDelta kMinimumPeriod = base::TimeDelta::FromMicroseconds(1);
// This runs on user thread
Timer::~Timer() {
std::lock_guard<std::recursive_mutex> api_lock(api_mutex_);
if (message_loop_thread_ != nullptr && message_loop_thread_->IsRunning()) {
CancelAndWait();
}
}
// This runs on user thread
bool Timer::Schedule(const base::WeakPtr<MessageLoopThread>& thread,
const tracked_objects::Location& from_here,
base::Closure task, base::TimeDelta delay) {
return ScheduleTaskHelper(thread, from_here, std::move(task), delay, false);
}
// This runs on user thread
bool Timer::SchedulePeriodic(const base::WeakPtr<MessageLoopThread>& thread,
const tracked_objects::Location& from_here,
base::Closure task, base::TimeDelta period) {
if (period < kMinimumPeriod) {
LOG(ERROR) << __func__ << ": period must be at least " << kMinimumPeriod;
return false;
}
return ScheduleTaskHelper(thread, from_here, std::move(task), period, true);
}
// This runs on user thread
bool Timer::ScheduleTaskHelper(const base::WeakPtr<MessageLoopThread>& thread,
const tracked_objects::Location& from_here,
base::Closure task, base::TimeDelta delay,
bool is_periodic) {
uint64_t time_now_us = time_get_os_boottime_us();
uint64_t time_next_task_us = time_now_us + delay.InMicroseconds();
std::lock_guard<std::recursive_mutex> api_lock(api_mutex_);
if (thread == nullptr) {
LOG(ERROR) << __func__ << ": thread must be non-null";
return false;
}
CancelAndWait();
expected_time_next_task_us_ = time_next_task_us;
task_ = std::move(task);
task_wrapper_.Reset(base::Bind(&Timer::RunTask, base::Unretained(this)));
message_loop_thread_ = thread;
period_ = delay;
is_periodic_ = is_periodic;
uint64_t time_until_next_us = time_next_task_us - time_get_os_boottime_us();
if (!thread->DoInThreadDelayed(
from_here, task_wrapper_.callback(),
base::TimeDelta::FromMicroseconds(time_until_next_us))) {
LOG(ERROR) << __func__
<< ": failed to post task to message loop for thread " << *thread
<< ", from " << from_here.ToString();
expected_time_next_task_us_ = 0;
task_wrapper_.Cancel();
message_loop_thread_ = nullptr;
period_ = {};
is_periodic_ = false;
return false;
}
return true;
}
// This runs on user thread
void Timer::Cancel() {
std::promise<void> promise;
CancelHelper(std::move(promise));
}
// This runs on user thread
void Timer::CancelAndWait() {
std::promise<void> promise;
auto future = promise.get_future();
CancelHelper(std::move(promise));
future.wait();
}
// This runs on user thread
void Timer::CancelHelper(std::promise<void> promise) {
std::lock_guard<std::recursive_mutex> api_lock(api_mutex_);
MessageLoopThread* scheduled_thread = message_loop_thread_.get();
if (scheduled_thread == nullptr) {
promise.set_value();
return;
}
if (scheduled_thread->GetThreadId() == base::PlatformThread::CurrentId()) {
CancelClosure(std::move(promise));
return;
}
scheduled_thread->DoInThread(
FROM_HERE, base::BindOnce(&Timer::CancelClosure, base::Unretained(this),
std::move(promise)));
}
// This runs on message loop thread
void Timer::CancelClosure(std::promise<void> promise) {
message_loop_thread_ = nullptr;
task_wrapper_.Cancel();
task_ = {};
period_ = base::TimeDelta();
is_periodic_ = false;
expected_time_next_task_us_ = 0;
promise.set_value();
}
// This runs on user thread
bool Timer::IsScheduled() const {
std::lock_guard<std::recursive_mutex> api_lock(api_mutex_);
return message_loop_thread_ != nullptr && message_loop_thread_->IsRunning();
}
// This runs on message loop thread
void Timer::RunTask() {
if (message_loop_thread_ == nullptr || !message_loop_thread_->IsRunning()) {
LOG(ERROR) << __func__
<< ": message_loop_thread_ is null or is not running";
return;
}
CHECK_EQ(message_loop_thread_->GetThreadId(),
base::PlatformThread::CurrentId())
<< ": task must run on message loop thread";
if (is_periodic_) {
RunPeriodicTask();
} else {
RunSingleTask();
}
}
// This runs on message loop thread
void Timer::RunPeriodicTask() {
int64_t period_us = period_.InMicroseconds();
expected_time_next_task_us_ += period_us;
uint64_t time_now_us = time_get_os_boottime_us();
int64_t remaining_time_us = expected_time_next_task_us_ - time_now_us;
if (remaining_time_us < 0) {
// if remaining_time_us is negative, schedule the task to the nearest
// multiple of period
remaining_time_us = (remaining_time_us % period_us + period_us) % period_us;
}
message_loop_thread_->DoInThreadDelayed(
FROM_HERE, task_wrapper_.callback(),
base::TimeDelta::FromMicroseconds(remaining_time_us));
uint64_t time_before_task_us = time_get_os_boottime_us();
task_.Run();
uint64_t time_after_task_us = time_get_os_boottime_us();
auto task_time_us =
static_cast<int64_t>(time_after_task_us - time_before_task_us);
if (task_time_us > period_.InMicroseconds()) {
LOG(ERROR) << __func__ << ": Periodic task execution took " << task_time_us
<< " microseconds, longer than interval "
<< period_.InMicroseconds() << " microseconds";
}
}
// This runs on message loop thread
void Timer::RunSingleTask() {
base::OnceClosure current_task = std::move(task_);
task_wrapper_.Cancel();
task_ = {};
period_ = base::TimeDelta();
expected_time_next_task_us_ = 0;
std::move(current_task).Run();
message_loop_thread_ = nullptr;
}
} // namespace common
} // namespace bluetooth
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