// 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/compiler_specific.h"
#include "base/macros.h"
#include "base/memory/scoped_ptr.h"
#include "net/http/bidirectional_stream_impl.h"
#include "net/http/http_stream_factory.h"
#include "net/log/net_log.h"

class GURL;

namespace net {

class HttpAuthController;
class HttpNetworkSession;
class HttpStream;
class HttpStreamRequest;
class IOBuffer;
class ProxyInfo;
class SpdyHeaderBlock;
struct BidirectionalStreamRequestInfo;
struct SSLConfig;

// 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.
// The BidirectionalStream must be torn down before the HttpNetworkSession.
class NET_EXPORT BidirectionalStream
    : public NON_EXPORTED_BASE(BidirectionalStreamImpl::Delegate),
      public NON_EXPORTED_BASE(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 BidirectionalStream::ReadData to start reading,
    // or call BidirectionalStream::SendData to send data.
    // The delegate should not call BidirectionalStream::Cancel
    // during this callback.
    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,
    // call BidirectionalStream::SendData to send data,
    // or call BidirectionalStream::Cancel to cancel the stream.
    virtual void OnHeadersReceived(const SpdyHeaderBlock& response_headers) = 0;

    // Called when a pending read is completed asynchronously.
    // |bytes_read| specifies how much data is read.
    // The delegate may call BidirectionalStream::ReadData to continue
    // reading, call BidirectionalStream::SendData to send data,
    // 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.
    // The delegate may call BidirectionalStream::ReadData to continue
    // reading, call BidirectionalStream::SendData to send data,
    // The delegate should not call BidirectionalStream::Cancel
    // during this callback.
    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.
    // The delegate is able to continue reading if there is no pending read and
    // EOF has not been received, or to send data if there is no pending send.
    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();

   private:
    DISALLOW_COPY_AND_ASSIGN(Delegate);
  };

  // Constructs a BidirectionalStream. |request_info| contains information about
  // the request, and must be non-NULL. |session| is the http network session
  // with which this request will be made. |delegate| must be non-NULL.
  // |session| and |delegate| must outlive |this|.
  BidirectionalStream(scoped_ptr<BidirectionalStreamRequestInfo> request_info,
                      HttpNetworkSession* session,
                      Delegate* delegate);

  // Constructor that accepts a Timer, which can be used in tests to control
  // the buffering of received data.
  BidirectionalStream(scoped_ptr<BidirectionalStreamRequestInfo> request_info,
                      HttpNetworkSession* session,
                      Delegate* delegate,
                      scoped_ptr<base::Timer> timer);

  // Cancels |stream_request_| or |stream_impl_| if applicable.
  // |this| should not be destroyed during Delegate::OnHeadersSent or
  // 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. If returns 0, there is no more data to
  // read. This should not be called before Delegate::OnHeadersReceived is
  // invoked, and should not be called again unless it returns with number
  // greater than 0 or until 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. If |end_stream| is true, the DATA frame will have an END_STREAM
  // flag.
  void SendData(IOBuffer* data, int length, bool end_stream);

  // If |stream_request_| is non-NULL, cancel it. If |stream_impl_| is
  // established, cancel it. No delegate method will be called after Cancel().
  // Any pending operations may or may not succeed.
  void Cancel();

  // Returns the protocol used by this stream. If stream has not been
  // established, return kProtoUnknown.
  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 established, 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:
  // BidirectionalStreamImpl::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 OnBidirectionalStreamImplReady(
      const SSLConfig& used_ssl_config,
      const ProxyInfo& used_proxy_info,
      BidirectionalStreamImpl* stream_impl) 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;

  // BidirectionalStreamRequestInfo used when requesting the stream.
  scoped_ptr<BidirectionalStreamRequestInfo> request_info_;
  const BoundNetLog net_log_;

  HttpNetworkSession* session_;

  Delegate* const delegate_;

  // Timer used to buffer data received in short time-spans and send a single
  // read completion notification.
  scoped_ptr<base::Timer> timer_;
  // HttpStreamRequest used to request a BidirectionalStreamImpl. This is NULL
  // if the request has been canceled or completed.
  scoped_ptr<HttpStreamRequest> stream_request_;
  // The underlying BidirectioanlStreamImpl used for this stream. It is
  // non-NULL, if the |stream_request_| successfully finishes.
  scoped_ptr<BidirectionalStreamImpl> stream_impl_;

  DISALLOW_COPY_AND_ASSIGN(BidirectionalStream);
};

}  // namespace net

#endif  // NET_HTTP_BIDIRECTIONAL_STREAM_H_