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// Copyright 2015 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.
#ifndef COMPONENTS_SCHEDULER_CHILD_SCHEDULER_HELPER_H_
#define COMPONENTS_SCHEDULER_CHILD_SCHEDULER_HELPER_H_
#include "components/scheduler/child/prioritizing_task_queue_selector.h"
#include "components/scheduler/child/task_queue_manager.h"
#include "components/scheduler/scheduler_export.h"
namespace base {
class TickClock;
}
namespace scheduler {
class NestableSingleThreadTaskRunner;
// Common scheduler functionality for default tasks.
class SCHEDULER_EXPORT SchedulerHelper {
public:
// NOTE |total_task_queue_count| must be >= TASK_QUEUE_COUNT.
// Category strings must have application lifetime (statics or
// literals). They may not include " chars.
SchedulerHelper(
scoped_refptr<NestableSingleThreadTaskRunner> main_task_runner,
const char* tracing_category,
const char* disabled_by_default_tracing_category,
const char* disabled_by_default_verbose_tracing_category,
size_t total_task_queue_count);
~SchedulerHelper();
// Returns the default task runner.
scoped_refptr<base::SingleThreadTaskRunner> DefaultTaskRunner();
// Returns the control task runner. Tasks posted to this runner are executed
// with the highest priority. Care must be taken to avoid starvation of other
// task queues.
scoped_refptr<base::SingleThreadTaskRunner> ControlTaskRunner();
// Returns the control task after wakeup runner. Tasks posted to this runner
// are executed with the highest priority but do not cause the scheduler to
// wake up. Care must be taken to avoid starvation of other task queues.
scoped_refptr<base::SingleThreadTaskRunner> ControlAfterWakeUpTaskRunner();
// Adds or removes a task observer from the scheduler. The observer will be
// notified before and after every executed task. These functions can only be
// called on the thread this class was created on.
void AddTaskObserver(base::MessageLoop::TaskObserver* task_observer);
void RemoveTaskObserver(base::MessageLoop::TaskObserver* task_observer);
// Shuts down the scheduler by dropping any remaining pending work in the work
// queues. After this call any work posted to the task runners will be
// silently dropped.
void Shutdown();
// Returns true if Shutdown() has been called. Otherwise returns false.
bool IsShutdown() const { return !task_queue_manager_.get(); }
// Keep SchedulerHelper::TaskQueueIdToString in sync with this enum.
enum QueueId {
DEFAULT_TASK_QUEUE,
CONTROL_TASK_QUEUE,
CONTROL_TASK_AFTER_WAKEUP_QUEUE,
// Must be the last entry.
TASK_QUEUE_COUNT,
FIRST_QUEUE_ID = DEFAULT_TASK_QUEUE,
};
static const char* TaskQueueIdToString(QueueId queue_id);
void CheckOnValidThread() const {
DCHECK(thread_checker_.CalledOnValidThread());
}
// Accessor methods.
base::TimeTicks Now() const;
scoped_refptr<base::SingleThreadTaskRunner> TaskRunnerForQueue(
size_t queue_index) const;
base::TimeTicks NextPendingDelayedTaskRunTime() const;
void SetQueueName(size_t queue_index, const char* name);
bool IsQueueEmpty(size_t queue_index) const;
TaskQueueManager::QueueState GetQueueState(size_t queue_index) const;
void SetQueuePriority(size_t queue_index,
PrioritizingTaskQueueSelector::QueuePriority priority);
void EnableQueue(size_t queue_index,
PrioritizingTaskQueueSelector::QueuePriority priority);
void DisableQueue(size_t queue_index);
bool IsQueueEnabled(size_t queue_index) const;
void SetPumpPolicy(size_t queue_index,
TaskQueueManager::PumpPolicy pump_policy);
void SetWakeupPolicy(size_t queue_index,
TaskQueueManager::WakeupPolicy wakeup_policy);
void PumpQueue(size_t queue_index);
uint64 GetQuiescenceMonitoredTaskQueueMask() const;
uint64 GetAndClearTaskWasRunOnQueueBitmap();
// Test helpers.
void SetTimeSourceForTesting(scoped_ptr<base::TickClock> time_source);
void SetWorkBatchSizeForTesting(size_t work_batch_size);
TaskQueueManager* GetTaskQueueManagerForTesting();
private:
friend class SchedulerHelperTest;
base::ThreadChecker thread_checker_;
scoped_ptr<PrioritizingTaskQueueSelector> task_queue_selector_;
scoped_ptr<TaskQueueManager> task_queue_manager_;
uint64 quiescence_monitored_task_queue_mask_;
scoped_refptr<base::SingleThreadTaskRunner> control_task_runner_;
scoped_refptr<base::SingleThreadTaskRunner> control_after_wakeup_task_runner_;
scoped_refptr<base::SingleThreadTaskRunner> default_task_runner_;
scoped_ptr<base::TickClock> time_source_;
const char* tracing_category_;
const char* disabled_by_default_tracing_category_;
DISALLOW_COPY_AND_ASSIGN(SchedulerHelper);
};
} // namespace scheduler
#endif // COMPONENTS_SCHEDULER_CHILD_SCHEDULER_HELPER_H_
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