Task Scheduler.

base/task_scheduler/utils.cc

+// 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/utils.h"
+
+#include <utility>
+
+#include "base/debug/task_annotator.h"
+#include "base/task_scheduler/delayed_task_manager.h"
+#include "base/task_scheduler/priority_queue.h"
+#include "base/task_scheduler/shutdown_manager.h"
+
+namespace base {
+namespace task_scheduler {
+
+const char kQueueFunctionName[] = "task_scheduler::PostTask";
+
+void PostTaskHelper(const Task& task,
+                    scoped_refptr<Sequence> sequence,
+                    PriorityQueue* priority_queue,
+                    ShutdownManager* shutdown_manager,
+                    DelayedTaskManager* delayed_task_manager) {
+  DCHECK(!task.task.is_null());
+  DCHECK(sequence.get());
+  DCHECK(priority_queue);
+  DCHECK(shutdown_manager);
+  DCHECK(delayed_task_manager);
+
+  debug::TaskAnnotator task_annotator;
+  task_annotator.DidQueueTask(kQueueFunctionName, task);
+
+  if (task.delayed_run_time.is_null())
+    PostTaskNowHelper(task, sequence, priority_queue, shutdown_manager);
+  else
+    delayed_task_manager->AddDelayedTask(task, sequence, priority_queue);
+}
+
+void PostTaskNowHelper(const Task& task,
+                       scoped_refptr<Sequence> sequence,
+                       PriorityQueue* priority_queue,
+                       ShutdownManager* shutdown_manager) {
+  DCHECK(!task.task.is_null());
+  DCHECK(sequence.get());
+  DCHECK(priority_queue);
+  DCHECK(shutdown_manager);
+
+  if (!shutdown_manager->ShouldPostTask(task.traits.shutdown_behavior()))
+    return;
+
+  size_t prev_num_tasks;
+  sequence->PushTask(make_scoped_ptr(new Task(task)), &prev_num_tasks);
+
+  if (prev_num_tasks == 0) {
+    // Get the sequence sort key before creating the transaction. This ensures
+    // that the sequence's lock is not held at the same time as the priority
+    // queue's lock.
+    SequenceSortKey sequence_sort_key = sequence->GetSortKey();
+    priority_queue->BeginTransaction()->PushSequence(sequence,
+                                                     sequence_sort_key);
+  }
+}
+
+}  // namespace task_scheduler
+}  // namespace base