Added a net::BidirectionalStream to expose a bidirectional streaming interface

net/http/bidirectional_stream.h

+// 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 NET_HTTP_BIDIRECTIONAL_STREAM_H_
+#define NET_HTTP_BIDIRECTIONAL_STREAM_H_
+
+#include <stdint.h>
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "net/base/request_priority.h"
+#include "net/http/bidirectional_stream_job.h"
+#include "net/http/bidirectional_stream_request_info.h"
+#include "net/http/http_stream_factory.h"
+#include "net/ssl/ssl_config.h"
+#include "url/gurl.h"
+
+namespace net {
+
+class BoundNetLog;
+class HttpAuthController;
+class HttpNetworkSession;
+class HttpStream;
+class HttpStreamRequest;
+class IOBuffer;
+class ProxyInfo;
+class SpdyHeaderBlock;
+
+// A class to do HTTP/2 bidirectional streaming. Note that at most one each of
+// ReadData or SendData should be in flight until the operation completes

[mef, 2015/12/15 22:59:40]

nit: end with .

[xunjieli, 2015/12/16 00:26:09]

Done.

+// The BidirectionalStream must be torn down before the HttpNetworkSession.
+class NET_EXPORT BidirectionalStream : public BidirectionalStreamJob::Delegate,
+                                       public HttpStreamRequest::Delegate {
+ public:
+  // Delegate interface to get notified of success of failure. Callbacks will be
+  // invoked asynchronously.
+  class NET_EXPORT Delegate {
+   public:
+    Delegate() {}
+
+    // Called when headers have been sent. This is called at most once for
+    // the lifetime of a stream.
+    // The delegate may call BidirectionalStreamJob::SendData to start
+    // sending data.

[mef, 2015/12/15 22:59:39]

or call BidirectionalStream::Cancel to cancel the stream.

[xunjieli, 2015/12/16 00:26:09]

It's illegal to call Cancel during OnHeadersSent or OnDataSent callback.
(See
https://code.google.com/p/chromium/codesearch#chromium/src/net/spdy/spdy_stre...)

I have updated the comments. Thanks for bring this up.

+    virtual void OnHeadersSent() = 0;
+
+    // Called when headers are received. This is called at most once for the
+    // lifetime of a stream.
+    // The delegate may call BidirectionalStream::ReadData to start reading
+    // or call BidirectionalStream::Cancel to cancel the stream.
+    virtual void OnHeadersReceived(const SpdyHeaderBlock& response_headers) = 0;
+
+    // Called when read is completed asynchronously. |bytes_read| specifies how
+    // much data is available.

[mef, 2015/12/15 22:59:40]

read -> pending read
is available -> is read.

[xunjieli, 2015/12/16 00:26:09]

Done.

+    // The delegate may call BidirectionalStream::ReadData to continue
+    // reading or call BidirectionalStream::Cancel to cancel the stream.
+    virtual void OnDataRead(int bytes_read) = 0;
+
+    // Called when the entire buffer passed through SendData is sent.

[mef, 2015/12/15 22:59:40]

Update comment similarly to OnDataRead().

[xunjieli, 2015/12/16 00:26:09]

Done.

+    virtual void OnDataSent() = 0;
+
+    // Called when trailers are received. This is called as soon as trailers
+    // are received, which can happen before a read completes.

[mef, 2015/12/15 22:59:40]

Maybe clarify that no action is required from the delegate?

[xunjieli, 2015/12/16 00:26:08]

Done.

+    virtual void OnTrailersReceived(const SpdyHeaderBlock& trailers) = 0;
+
+    // Called when the stream is closed or an error occurred.
+    // No other delegate functions will be called after this.
+    virtual void OnFailed(int error) = 0;
+
+   protected:
+    virtual ~Delegate() {}

[mef, 2015/12/15 22:59:40]

Should {} go into .cc file?

[xunjieli, 2015/12/16 00:26:09]

Done. Good catch. Thanks!

+
+   private:
+    DISALLOW_COPY_AND_ASSIGN(Delegate);
+  };
+
+  BidirectionalStream(const BidirectionalStreamRequestInfo& request_info,

[mef, 2015/12/15 22:59:40]

need comment, especially considering that this is main constructor.

[xunjieli, 2015/12/16 00:26:09]

Done.

+                      RequestPriority priority,
+                      HttpNetworkSession* session,
+                      Delegate* delegate);
+
+  // Constructor that accepts a Timer, which can be used in tests to control
+  // the buffering of received data.
+  BidirectionalStream(const BidirectionalStreamRequestInfo& request_info,

[mef, 2015/12/15 22:59:39]

FWIW HttpStream-related classes pass request_info as pointer to avoid copying. I
think we should do the same for BidirectionalStream.

[xunjieli, 2015/12/16 00:26:08]

Done.

+                      RequestPriority priority,
+                      HttpNetworkSession* session,
+                      Delegate* delegate,
+                      scoped_ptr<base::Timer> timer);
+
+  // Cancels |stream_request_| or |stream_job_| if applicable.
+  // |this| should not be destroyed during Delegate::OnHeadersSent or

[mef, 2015/12/15 22:59:40]

That's an interesting comment. Why not? Do we need tests for this?

[xunjieli, 2015/12/16 00:26:08]

It's illegal to call Cancel during OnHeadersSent or OnDataSent callback.
(See
https://code.google.com/p/chromium/codesearch#chromium/src/net/spdy/spdy_stre...)

Not sure how this can be tested. I am not sure how to catch a DCHECK failure in
the test.

[mef, 2015/12/16 20:24:40]

Acknowledged. This should not be a problem for CronetBidirectionalStream as
Destroy is always posted to the network thread and never invoked synchronously.

+  // Delegate::OnDataSent.
+  ~BidirectionalStream() override;
+
+  // Reads at most |buf_len| bytes into |buf|. Returns the number of bytes read,
+  // or ERR_IO_PENDING if the read is to be completed asynchronously, or an
+  // error code if any error occurred.
+  // This should not be called before Delegate::OnHeadersSent is invoked, and

[mef, 2015/12/15 22:59:40]

OnHeadersSent -> OnHeadersReceived?

[xunjieli, 2015/12/16 00:26:09]

Done.

+  // should not be called again unless it IO completes synchronously or until

[mef, 2015/12/15 22:59:39]

IO completes -> returns

[xunjieli, 2015/12/16 00:26:09]

Done.

+  // Delegate::OnDataRead is invoked.
+  int ReadData(IOBuffer* buf, int buf_len);
+
+  // Sends data. This should not be called before Delegate::OnHeadersSent is
+  // invoked, and should not be called again until Delegate::OnDataSent is
+  // invoked.
+  void SendData(IOBuffer* data, int length, bool end_stream);
+
+  // If there is |stream_request_|, cancel it. If |stream_job_| is established,
+  // cancel it. No delegate method will be called after Cancel().
+  // Any pending operations may or may not succeed.
+  void Cancel();
+
+  // Getters that should only be called after Delegate::OnHeadersSent:
+
+  // Returns the protocol used by this stream. If stream has not been
+  // stablished, return kProtoUnknown.

[mef, 2015/12/15 22:59:40]

established (here and below).

[xunjieli, 2015/12/16 00:26:08]

Done.

+  NextProto GetProtocol() const;
+
+  // Total number of bytes received over the network of SPDY data, headers, and
+  // push_promise frames associated with this stream, including the size of
+  // frame headers, after SSL decryption and not including proxy overhead.
+  // If stream has not been stablished, return 0.
+  int64_t GetTotalReceivedBytes() const;
+
+  // Total number of bytes sent over the network of SPDY frames associated with
+  // this stream, including the size of frame headers, before SSL encryption and
+  // not including proxy overhead. Note that some SPDY frames such as pings are
+  // not associated with any stream, and are not included in this value.
+  int64_t GetTotalSentBytes() const;
+
+  // TODO(xunjieli): Implement a method to do flow control and a method to ping
+  // remote end point.
+
+ private:
+  // BidirectionalStreamJob::Delegate implementation:
+  void OnHeadersSent() override;
+  void OnHeadersReceived(const SpdyHeaderBlock& response_headers) override;
+  void OnDataRead(int bytes_read) override;
+  void OnDataSent() override;
+  void OnTrailersReceived(const SpdyHeaderBlock& trailers) override;
+  void OnFailed(int error) override;
+
+  // HttpStreamRequest::Delegate implementation:
+  void OnStreamReady(const SSLConfig& used_ssl_config,
+                     const ProxyInfo& used_proxy_info,
+                     HttpStream* stream) override;
+  void OnBidirectionalStreamJobReady(const SSLConfig& used_ssl_config,
+                                     const ProxyInfo& used_proxy_info,
+                                     BidirectionalStreamJob* stream) override;
+  void OnWebSocketHandshakeStreamReady(
+      const SSLConfig& used_ssl_config,
+      const ProxyInfo& used_proxy_info,
+      WebSocketHandshakeStreamBase* stream) override;
+  void OnStreamFailed(int status,
+                      const SSLConfig& used_ssl_config,
+                      SSLFailureState ssl_failure_state) override;
+  void OnCertificateError(int status,
+                          const SSLConfig& used_ssl_config,
+                          const SSLInfo& ssl_info) override;
+  void OnNeedsProxyAuth(const HttpResponseInfo& response_info,
+                        const SSLConfig& used_ssl_config,
+                        const ProxyInfo& used_proxy_info,
+                        HttpAuthController* auth_controller) override;
+  void OnNeedsClientAuth(const SSLConfig& used_ssl_config,
+                         SSLCertRequestInfo* cert_info) override;
+  void OnHttpsProxyTunnelResponse(const HttpResponseInfo& response_info,
+                                  const SSLConfig& used_ssl_config,
+                                  const ProxyInfo& used_proxy_info,
+                                  HttpStream* stream) override;
+  void OnQuicBroken() override;
+
+  const BidirectionalStreamRequestInfo request_info_;

[mef, 2015/12/15 22:59:40]

can this be a scoped_ptr<BidirectionalStreamRequestInfo>? 

If yes, and if it could take an ownership of request_info passed to constructor,
then we would avoid cloning of that structure.

[xunjieli, 2015/12/16 00:26:09]

Done. I think it should take a raw pointer. Whoever owns this bidi stream should
own the request_info, and ensure it is destroyed after bidi stream. I think this
is slightly more consistent with SpdyHttpStream.

[mef, 2015/12/16 20:24:40]

Excellent, sgtm!

+  const RequestPriority priority_;
+  const BoundNetLog net_log_;
+
+  Delegate* const delegate_;
+
+  scoped_ptr<base::Timer> timer_;
+  scoped_ptr<HttpStreamRequest> stream_request_;
+  scoped_ptr<BidirectionalStreamJob> stream_job_;
+
+  DISALLOW_COPY_AND_ASSIGN(BidirectionalStream);
+};
+
+}  // namespace net
+
+#endif  // NET_HTTP_BIDIRECTIONAL_STREAM_H_