| // Copyright 2013 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "base/message_loop/incoming_task_queue.h" |
| |
| #include "base/location.h" |
| #include "base/message_loop/message_loop.h" |
| #include "base/synchronization/waitable_event.h" |
| |
| namespace base { |
| namespace internal { |
| |
| IncomingTaskQueue::IncomingTaskQueue(MessageLoop* message_loop) |
| : message_loop_(message_loop), |
| next_sequence_num_(0) { |
| } |
| |
| bool IncomingTaskQueue::AddToIncomingQueue( |
| const tracked_objects::Location& from_here, |
| const Closure& task, |
| TimeDelta delay, |
| bool nestable) { |
| AutoLock locked(incoming_queue_lock_); |
| PendingTask pending_task( |
| from_here, task, CalculateDelayedRuntime(delay), nestable); |
| return PostPendingTask(&pending_task); |
| } |
| |
| bool IncomingTaskQueue::IsHighResolutionTimerEnabledForTesting() { |
| #if defined(OS_WIN) |
| return !high_resolution_timer_expiration_.is_null(); |
| #else |
| return true; |
| #endif |
| } |
| |
| bool IncomingTaskQueue::IsIdleForTesting() { |
| AutoLock lock(incoming_queue_lock_); |
| return incoming_queue_.empty(); |
| } |
| |
| void IncomingTaskQueue::ReloadWorkQueue(TaskQueue* work_queue) { |
| // Make sure no tasks are lost. |
| DCHECK(work_queue->empty()); |
| |
| // Acquire all we can from the inter-thread queue with one lock acquisition. |
| AutoLock lock(incoming_queue_lock_); |
| if (!incoming_queue_.empty()) |
| incoming_queue_.Swap(work_queue); // Constant time |
| |
| DCHECK(incoming_queue_.empty()); |
| } |
| |
| void IncomingTaskQueue::WillDestroyCurrentMessageLoop() { |
| #if defined(OS_WIN) |
| // If we left the high-resolution timer activated, deactivate it now. |
| // Doing this is not-critical, it is mainly to make sure we track |
| // the high resolution timer activations properly in our unit tests. |
| if (!high_resolution_timer_expiration_.is_null()) { |
| Time::ActivateHighResolutionTimer(false); |
| high_resolution_timer_expiration_ = TimeTicks(); |
| } |
| #endif |
| |
| AutoLock lock(incoming_queue_lock_); |
| message_loop_ = NULL; |
| } |
| |
| IncomingTaskQueue::~IncomingTaskQueue() { |
| // Verify that WillDestroyCurrentMessageLoop() has been called. |
| DCHECK(!message_loop_); |
| } |
| |
| TimeTicks IncomingTaskQueue::CalculateDelayedRuntime(TimeDelta delay) { |
| TimeTicks delayed_run_time; |
| if (delay > TimeDelta()) { |
| delayed_run_time = TimeTicks::Now() + delay; |
| |
| #if defined(OS_WIN) |
| if (high_resolution_timer_expiration_.is_null()) { |
| // Windows timers are granular to 15.6ms. If we only set high-res |
| // timers for those under 15.6ms, then a 18ms timer ticks at ~32ms, |
| // which as a percentage is pretty inaccurate. So enable high |
| // res timers for any timer which is within 2x of the granularity. |
| // This is a tradeoff between accuracy and power management. |
| bool needs_high_res_timers = delay.InMilliseconds() < |
| (2 * Time::kMinLowResolutionThresholdMs); |
| if (needs_high_res_timers) { |
| if (Time::ActivateHighResolutionTimer(true)) { |
| high_resolution_timer_expiration_ = TimeTicks::Now() + |
| TimeDelta::FromMilliseconds( |
| MessageLoop::kHighResolutionTimerModeLeaseTimeMs); |
| } |
| } |
| } |
| #endif |
| } else { |
| DCHECK_EQ(delay.InMilliseconds(), 0) << "delay should not be negative"; |
| } |
| |
| #if defined(OS_WIN) |
| if (!high_resolution_timer_expiration_.is_null()) { |
| if (TimeTicks::Now() > high_resolution_timer_expiration_) { |
| Time::ActivateHighResolutionTimer(false); |
| high_resolution_timer_expiration_ = TimeTicks(); |
| } |
| } |
| #endif |
| |
| return delayed_run_time; |
| } |
| |
| bool IncomingTaskQueue::PostPendingTask(PendingTask* pending_task) { |
| // Warning: Don't try to short-circuit, and handle this thread's tasks more |
| // directly, as it could starve handling of foreign threads. Put every task |
| // into this queue. |
| |
| // This should only be called while the lock is taken. |
| incoming_queue_lock_.AssertAcquired(); |
| |
| if (!message_loop_) { |
| pending_task->task.Reset(); |
| return false; |
| } |
| |
| // Initialize the sequence number. The sequence number is used for delayed |
| // tasks (to faciliate FIFO sorting when two tasks have the same |
| // delayed_run_time value) and for identifying the task in about:tracing. |
| pending_task->sequence_num = next_sequence_num_++; |
| |
| message_loop_->task_annotator()->DidQueueTask("MessageLoop::PostTask", |
| *pending_task); |
| |
| bool was_empty = incoming_queue_.empty(); |
| incoming_queue_.push(*pending_task); |
| pending_task->task.Reset(); |
| |
| // Wake up the pump. |
| message_loop_->ScheduleWork(was_empty); |
| |
| return true; |
| } |
| |
| } // namespace internal |
| } // namespace base |