TaskScheduler [3/9] Task and Sequence

base/task_scheduler/sequence_sort_key.cc

Index: base/task_scheduler/sequence_sort_key.cc
diff --git a/base/task_scheduler/sequence_sort_key.cc b/base/task_scheduler/sequence_sort_key.cc
new file mode 100644
index 0000000000000000000000000000000000000000..5a07268b92e6c618b8fc64b4b6c9b5722b1803aa
--- /dev/null
+++ b/base/task_scheduler/sequence_sort_key.cc
@@ -0,0 +1,33 @@
+// 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/sequence_sort_key.h"
+
+namespace base {
+namespace internal {
+
+SequenceSortKey::SequenceSortKey(TaskPriority priority,
+                                 TimeTicks next_task_sequenced_time)
+    : priority_(priority),
+      next_task_sequenced_time_(next_task_sequenced_time) {}
+
+bool SequenceSortKey::operator<(const SequenceSortKey& other) const {
+  // This SequenceSortKey is considered less important than |other| if it has a
+  // lower priority or if it has the same priority but its next task was posted
+  // later than |other|'s.
+  const int priority_diff =
+      static_cast<TaskPriorityUnderlyingType>(priority_) -
+      static_cast<TaskPriorityUnderlyingType>(other.priority_);
+  return priority_diff != 0

[robliao, 2016/02/19 02:33:43]

Remove the double negative by changing this to == and inverting the two branches
below.

[fdoray, 2016/02/19 14:12:14]

Done.

[gab, 2016/02/19 16:50:47]

I typically prefer equality check first but here prefer != as it allows the
rules to be in their order of importance and reads better (i.e. "if priority
isn't the same, base result on priority, otherwise on time" instead of "if
priority is the same, use time, otherwise do use priority").

[fdoray, 2016/02/19 22:28:29]

Done.

+             ? priority_diff < 0
+             : next_task_sequenced_time_ > other.next_task_sequenced_time_;
+}
+
+bool SequenceSortKey::operator==(const SequenceSortKey& other) const {
+  return priority_ == other.priority_ &&
+         next_task_sequenced_time_ == other.next_task_sequenced_time_;
+}
+
+}  // namespace internal
+}  // namespace base