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base / task / thread_pool / task_source_sort_key.h [blame]
// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_TASK_THREAD_POOL_TASK_SOURCE_SORT_KEY_H_
#define BASE_TASK_THREAD_POOL_TASK_SOURCE_SORT_KEY_H_
#include "base/base_export.h"
#include "base/task/task_traits.h"
#include "base/time/time.h"
namespace base {
namespace internal {
// An immutable but assignable representation of the priority of a Sequence.
class BASE_EXPORT TaskSourceSortKey final {
public:
TaskSourceSortKey() = default;
TaskSourceSortKey(TaskPriority priority,
TimeTicks ready_time,
uint8_t worker_count = 0);
TaskPriority priority() const { return priority_; }
uint8_t worker_count() const { return worker_count_; }
TimeTicks ready_time() const { return ready_time_; }
// Used for a max-heap.
bool operator<(const TaskSourceSortKey& other) const;
bool operator==(const TaskSourceSortKey& other) const {
return priority_ == other.priority_ &&
worker_count_ == other.worker_count_ &&
ready_time_ == other.ready_time_;
}
bool operator!=(const TaskSourceSortKey& other) const {
return !(other == *this);
}
private:
// The private section allows this class to keep its immutable property while
// being copy-assignable (i.e. instead of making its members const).
// Highest task priority in the sequence at the time this sort key was
// created.
TaskPriority priority_;
// Number of workers running the task source, used as secondary sort key
// prioritizing task sources with fewer workers.
uint8_t worker_count_;
// Time since the task source has been ready to run upcoming work, used as
// secondary sort key after |worker_count| prioritizing older task sources.
TimeTicks ready_time_;
};
} // namespace internal
} // namespace base
#endif // BASE_TASK_THREAD_POOL_TASK_SOURCE_SORT_KEY_H_