Index: components/scheduler/child/task_queue_sets.h |
diff --git a/components/scheduler/child/task_queue_sets.h b/components/scheduler/child/task_queue_sets.h |
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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_TASK_QUEUE_SETS_H_ |
+#define COMPONENTS_SCHEDULER_CHILD_TASK_QUEUE_SETS_H_ |
+ |
+#include <map> |
+#include <vector> |
+ |
+#include "base/macros.h" |
+#include "base/trace_event/trace_event_argument.h" |
+#include "components/scheduler/child/task_queue.h" |
+#include "components/scheduler/scheduler_export.h" |
+ |
+namespace scheduler { |
+namespace internal { |
+class TaskQueueImpl; |
+ |
+class SCHEDULER_EXPORT TaskQueueSets { |
+ public: |
+ explicit TaskQueueSets(size_t num_sets); |
+ ~TaskQueueSets(); |
+ |
+ // O(log num queues) |
+ void RemoveQueue(internal::TaskQueueImpl* queue); |
+ |
+ // O(log num queues) |
+ void AssignQueueToSet(internal::TaskQueueImpl* queue, size_t set_index); |
+ |
+ // O(log num queues) |
+ void OnPushQueue(internal::TaskQueueImpl* queue); |
+ |
+ // If empty it's O(1) amortized, otherwise it's O(log num queues) |
+ void OnPopQueue(internal::TaskQueueImpl* queue); |
+ |
+ // O(1) |
+ bool GetOldestQueueInSet(size_t set_index, |
+ internal::TaskQueueImpl** out_queue) const; |
+ |
+ // O(1) |
+ bool IsSetEmpty(size_t set_index) const; |
+ |
+ private: |
+ struct EnqueueOrderComparitor { |
+ // The enqueueorder numbers are generated in sequence. These will |
+ // eventually overflow and roll-over to negative numbers. We must take care |
+ // to preserve the ordering of the map when this happens. |
+ // NOTE we assume that tasks don't get starved for extended periods so that |
+ // the task queue ages in a set have at most one roll-over. |
+ // NOTE signed integer overflow behavior is undefined in C++ so we can't |
+ // use the (a - b) < 0 trick here, because the optimizer won't necessarily |
+ // do what we expect. |
+ // TODO(alexclarke): Consider making age and sequence_num unsigned, because |
+ // unsigned integer overflow behavior is defined. |
+ bool operator()(int a, int b) const { |
+ if (a < 0 && b >= 0) |
+ return false; |
+ if (b < 0 && a >= 0) |
+ return true; |
+ return a < b; |
+ } |
+ }; |
+ |
+ typedef std::map<int, internal::TaskQueueImpl*, EnqueueOrderComparitor> |
+ EnqueueOrderToQueueMap; |
+ std::vector<EnqueueOrderToQueueMap> enqueue_order_to_queue_maps_; |
+ |
+ DISALLOW_COPY_AND_ASSIGN(TaskQueueSets); |
+}; |
+ |
+} // namespace internal |
+} // namespace scheduler |
+ |
+#endif // COMPONENTS_SCHEDULER_CHILD_TASK_QUEUE_SETS_H_ |