Transform RefCountedDeleteOnMessageLoop to RefCountedDeleteOnSequence.

base/memory/ref_counted_delete_on_sequence.h

+// Copyright 2013 The Chromium Authors. All rights reserved.

[gab, 2016/12/22 20:32:28]

Note: preferable to tweak git cl upload --similarity=XX to get a better diff in
such situations.

[fdoray, 2016/12/23 12:49:30]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_MEMORY_REF_COUNTED_DELETE_ON_SEQUENCE_H_
+#define BASE_MEMORY_REF_COUNTED_DELETE_ON_SEQUENCE_H_
+
+#include <utility>
+
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/sequenced_task_runner.h"
+
+namespace base {
+
+// RefCountedDeleteOnSequence is similar to RefCountedThreadSafe, and ensures
+// that the object will be deleted on a specified sequence.
+//
+// Sample usage:
+// class Foo : public RefCountedDeleteOnSequence<Foo> {
+//
+//   Foo(scoped_refptr<SequencedTaskRunner> task_runner)
+//       : RefCountedDeleteOnSequence<Foo>(std::move(task_runner)) {}
+//   ...
+//  private:
+//   friend class RefCountedDeleteOnSequence<Foo>;
+//   friend class DeleteHelper<Foo>;
+//
+//   ~Foo();
+// };
+template <class T>
+class RefCountedDeleteOnSequence : public subtle::RefCountedThreadSafeBase {
+ public:
+  // A SequencedTaskRunner for the current sequence can be acquired by calling
+  // SequencedTaskRunnerHandle::Get().
+  RefCountedDeleteOnSequence(scoped_refptr<SequencedTaskRunner> task_runner)
+      : task_runner_(std::move(task_runner)) {
+    DCHECK(task_runner_);
+  }
+
+  void AddRef() const { subtle::RefCountedThreadSafeBase::AddRef(); }
+
+  void Release() const {
+    if (subtle::RefCountedThreadSafeBase::Release())
+      DestructOnSequence();
+  }
+
+ protected:
+  friend class DeleteHelper<RefCountedDeleteOnSequence>;
+  ~RefCountedDeleteOnSequence() = default;
+
+ private:
+  void DestructOnSequence() const {
+    const T* t = static_cast<const T*>(this);
+    if (task_runner_->RunsTasksOnCurrentThread())
+      delete t;
+    else
+      task_runner_->DeleteSoon(FROM_HERE, t);
+  }
+
+  const scoped_refptr<SequencedTaskRunner> task_runner_;
+
+  DISALLOW_COPY_AND_ASSIGN(RefCountedDeleteOnSequence);
+};
+
+}  // namespace base
+
+#endif  // BASE_MEMORY_REF_COUNTED_DELETE_ON_SEQUENCE_H_