Index: base/task_scheduler/task_tracker.cc |
diff --git a/base/task_scheduler/task_tracker.cc b/base/task_scheduler/task_tracker.cc |
new file mode 100644 |
index 0000000000000000000000000000000000000000..7691f8be19a8ae2678c02fcc6065cad05da68f6c |
--- /dev/null |
+++ b/base/task_scheduler/task_tracker.cc |
@@ -0,0 +1,132 @@ |
+// Copyright 2016 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/task_scheduler/task_tracker.h" |
+ |
+#include "base/callback.h" |
+#include "base/debug/task_annotator.h" |
+ |
+namespace base { |
+namespace internal { |
+ |
+namespace { |
+const char kQueueFunctionName[] = "base::PostTask"; |
+} // namespace |
+ |
+TaskTracker::TaskTracker() = default; |
+TaskTracker::~TaskTracker() = default; |
+ |
+void TaskTracker::Shutdown() { |
+ AutoSchedulerLock auto_lock(lock_); |
+ |
+ DCHECK(!shutdown_completed_ && !shutdown_cv_) |
+ << "TaskTracker::Shutdown() should only be invoked once."; |
+ |
+ shutdown_cv_ = lock_.CreateConditionVariable(); |
+ |
+ // Wait until the number of tasks blocking shutdown is zero. |
+ while (num_tasks_blocking_shutdown_ != 0) |
+ shutdown_cv_->Wait(); |
+ |
+ shutdown_cv_.reset(); |
+ shutdown_completed_ = true; |
+} |
+ |
+void TaskTracker::PostTask( |
+ const Callback<void(scoped_ptr<Task>)>& post_task_callback, |
+ scoped_ptr<Task> task) { |
+ DCHECK(!post_task_callback.is_null()); |
+ DCHECK(task); |
+ |
+ if (!BeforePostTask(task->traits.shutdown_behavior())) |
+ return; |
+ |
+ debug::TaskAnnotator task_annotator; |
+ task_annotator.DidQueueTask(kQueueFunctionName, *task.get()); |
+ |
+ post_task_callback.Run(std::move(task)); |
+} |
+ |
+void TaskTracker::RunTask(const Task* task) { |
+ DCHECK(task); |
+ |
+ const TaskShutdownBehavior shutdown_behavior = |
+ task->traits.shutdown_behavior(); |
+ if (!BeforeRunTask(shutdown_behavior)) |
+ return; |
+ |
+ debug::TaskAnnotator task_annotator; |
+ task_annotator.RunTask(kQueueFunctionName, *task); |
+ |
+ AfterRunTask(shutdown_behavior); |
+} |
+ |
+bool TaskTracker::IsShuttingDownForTesting() const { |
+ AutoSchedulerLock auto_lock(lock_); |
+ return shutdown_cv_.get() != nullptr; |
+} |
+ |
+bool TaskTracker::BeforePostTask(TaskShutdownBehavior shutdown_behavior) { |
+ AutoSchedulerLock auto_lock(lock_); |
+ |
+ if (shutdown_completed_) |
+ return false; |
+ |
+ if (shutdown_behavior == TaskShutdownBehavior::BLOCK_SHUTDOWN) { |
+ // BLOCK_SHUTDOWN tasks block shutdown between the moment they are posted |
+ // and the moment they complete their execution. |
+ ++num_tasks_blocking_shutdown_; |
+ |
+ // TODO(fdoray): Add a UMA histogram with the number of BLOCK_SHUTDOWN tasks |
robliao
2016/03/17 23:34:21
Should we go ahead and do this now?
fdoray
2016/03/18 20:35:39
Done.
|
+ // posted during shutdown. |
+ |
+ return true; |
+ } |
+ |
+ return !shutdown_cv_; |
+} |
+ |
+bool TaskTracker::BeforeRunTask(TaskShutdownBehavior shutdown_behavior) { |
+ AutoSchedulerLock auto_lock(lock_); |
+ |
+ if (shutdown_completed_) { |
+ // A BLOCK_SHUTDOWN task posted after shutdown has completed is an ordering |
+ // bug. This DCHECK aims to catch those early. |
+ DCHECK_NE(TaskShutdownBehavior::BLOCK_SHUTDOWN, shutdown_behavior); |
+ return false; |
+ } |
+ |
+ switch (shutdown_behavior) { |
+ case TaskShutdownBehavior::BLOCK_SHUTDOWN: |
+ return true; |
+ |
+ case TaskShutdownBehavior::SKIP_ON_SHUTDOWN: |
+ if (shutdown_cv_) |
+ return false; |
+ |
+ // SKIP_ON_SHUTDOWN tasks block shutdown while they are running. |
+ ++num_tasks_blocking_shutdown_; |
+ return true; |
+ |
+ case TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN: |
+ return !shutdown_cv_; |
+ } |
+ |
+ NOTREACHED(); |
+ return false; |
+} |
+ |
+void TaskTracker::AfterRunTask(TaskShutdownBehavior shutdown_behavior) { |
+ if (shutdown_behavior == TaskShutdownBehavior::BLOCK_SHUTDOWN || |
+ shutdown_behavior == TaskShutdownBehavior::SKIP_ON_SHUTDOWN) { |
+ AutoSchedulerLock auto_lock(lock_); |
+ DCHECK_GT(num_tasks_blocking_shutdown_, 0U); |
+ --num_tasks_blocking_shutdown_; |
+ if (num_tasks_blocking_shutdown_ == 0 && shutdown_cv_) |
+ shutdown_cv_->Signal(); |
+ } |
+} |
+ |
+} // namespace internal |
+} // namespace base |