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// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CC_RASTER_SINGLE_THREAD_TASK_GRAPH_RUNNER_H_
#define CC_RASTER_SINGLE_THREAD_TASK_GRAPH_RUNNER_H_
#include <memory>
#include <string>
#include "base/synchronization/condition_variable.h"
#include "base/thread_annotations.h"
#include "base/threading/simple_thread.h"
#include "cc/raster/task_graph_runner.h"
#include "cc/raster/task_graph_work_queue.h"
namespace base {
class SimpleThread;
}
namespace cc {
// Runs TaskGraphs asynchronously using a single worker thread.
class CC_EXPORT SingleThreadTaskGraphRunner
: public TaskGraphRunner,
public base::DelegateSimpleThread::Delegate {
public:
SingleThreadTaskGraphRunner();
~SingleThreadTaskGraphRunner() override;
// Overridden from TaskGraphRunner:
NamespaceToken GenerateNamespaceToken() override;
void ScheduleTasks(NamespaceToken token, TaskGraph* graph) override;
void ExternalDependencyCompletedForTask(NamespaceToken token,
scoped_refptr<Task> task) override;
void WaitForTasksToFinishRunning(NamespaceToken token) override;
void CollectCompletedTasks(NamespaceToken token,
Task::Vector* completed_tasks) override;
void RunTasksUntilIdleForTest() override;
// Overridden from base::DelegateSimpleThread::Delegate:
void Run() override;
void Start(const std::string& thread_name,
const base::SimpleThread::Options& thread_options);
void Shutdown();
private:
// Returns true if there was a task to run.
bool RunTaskWithLockAcquired() EXCLUSIVE_LOCKS_REQUIRED(lock_);
std::unique_ptr<base::SimpleThread> thread_;
// Lock to exclusively access all the following members that are used to
// implement the TaskRunner interfaces.
base::Lock lock_;
// Stores the actual tasks to be run by this runner, sorted by priority.
TaskGraphWorkQueue work_queue_ GUARDED_BY(lock_);
// Condition variable that is waited on by Run() until new tasks are ready to
// run or shutdown starts.
base::ConditionVariable has_ready_to_run_tasks_cv_;
// Condition variable that is waited on by origin threads until a namespace
// has finished running all associated tasks.
base::ConditionVariable has_namespaces_with_finished_running_tasks_cv_;
// Condition variable that is waited on by origin threads until there are no
// more tasks ready to run in the queue.
base::ConditionVariable is_idle_cv_;
// Set during shutdown. Tells Run() to return when no more tasks are pending.
bool shutdown_ GUARDED_BY(lock_) = false;
};
} // namespace cc
#endif // CC_RASTER_SINGLE_THREAD_TASK_GRAPH_RUNNER_H_
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