ServiceWorker: Use mojo's data pipe for respondWith(stream)

content/browser/service_worker/service_worker_data_pipe_reader.h

+// Copyright 2017 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 CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_DATA_PIPE_READER_H_
+#define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_DATA_PIPE_READER_H_
+
+#include "base/memory/ref_counted.h"
+#include "content/common/content_export.h"
+#include "mojo/public/cpp/bindings/binding.h"
+#include "mojo/public/cpp/system/data_pipe.h"
+#include "mojo/public/cpp/system/simple_watcher.h"
+#include "third_party/WebKit/public/platform/modules/serviceworker/service_worker_stream_handle.mojom.h"
+
+namespace net {
+class IOBuffer;
+}  // namespace net
+
+namespace content {
+
+class ServiceWorkerURLRequestJob;
+class ServiceWorkerVersion;
+

[falken, 2017/04/18 05:05:33]

nit: add a class-level comment like ServiceWorkerStreamReader had. what does the
class do, who owns it.

[shimazu, 2017/04/19 05:49:46]

Done.

+class CONTENT_EXPORT ServiceWorkerDataPipeReader
+    : public blink::mojom::ServiceWorkerStreamCallback {
+ public:
+  ServiceWorkerDataPipeReader(
+      ServiceWorkerURLRequestJob* owner,
+      scoped_refptr<ServiceWorkerVersion> streaming_version,
+      blink::mojom::ServiceWorkerStreamHandlePtr stream_handle);
+  ~ServiceWorkerDataPipeReader() override;
+  void Start();

[falken, 2017/04/18 05:05:33]

Can you document it calls owner_->OnResponseStarted.

[shimazu, 2017/04/19 05:49:46]

Done.

+
+  // Copies the data provided from the service worker to |buf| up to |bus_size|

[falken, 2017/04/18 05:05:33]

nit: buf_size

[shimazu, 2017/04/19 05:49:46]

Done.

+  // bytes. The returned value is the size actually copied to |buf|. It will be
+  // net::OK when all data have received, and net::ERR_* when failure or pending
+  // io.

[falken, 2017/04/18 05:05:33]

It's kind of vague to group failure and pending IO together. Should this comment
just say "Same as URLRequestJob::ReadRawData" like ServiceWorkerStreamReader
did? What happens when ERR_IO_PENDING is returned, how does the caller know when
the operation completes?

[shimazu, 2017/04/19 05:49:46]

Done.

+  int ReadRawData(net::IOBuffer* buf, int buf_size);
+
+  // Implements mojom::ServiceWorkerStreamCallback.
+  void OnCompleted() override;
+  void OnAborted() override;
+
+ private:
+  enum class State { STREAMING, COMPLETED, ABORTED };
+
+  // Callback method for |handle_watcher_|.
+  void OnHandleGotSignal(MojoResult);
+
+  // Finalizes the job. These must be called when state() is not
+  // State::STREAMING.
+  int SyncComplete();
+  void AsyncComplete();
+
+  State state();
+
+  ServiceWorkerURLRequestJob* owner_;
+  scoped_refptr<ServiceWorkerVersion> streaming_version_;
+  scoped_refptr<net::IOBuffer> stream_pending_buffer_;
+  int stream_pending_buffer_size_ = 0;
+  mojo::SimpleWatcher handle_watcher_;
+  mojo::ScopedDataPipeConsumerHandle stream_;
+  mojo::Binding<blink::mojom::ServiceWorkerStreamCallback> binding_;
+  // State notified via ServiceWorkerStreamCallback. |producer_state_| is
+  // STREAMING until OnCompleted or OnAborted is called. Note that |stream_|
+  // might be closed even if |producer_state_| is STREAMING. In order to see the
+  // state of ServiceWorkerDataPipeReader, use state() instead.
+  State producer_state_;

[falken, 2017/04/18 05:05:33]

nit: initialize both |buffer_size_| and |producer_state_| in the same place,
either in the constructor or here.

[shimazu, 2017/04/19 05:49:46]

Done.

+
+  DISALLOW_COPY_AND_ASSIGN(ServiceWorkerDataPipeReader);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_DATA_PIPE_READER_H_