// Copyright (c) 2012 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_HTTP_NETWORK_TRANSACTION_H_
#define NET_HTTP_HTTP_NETWORK_TRANSACTION_H_

#include <string>

#include "base/basictypes.h"
#include "base/gtest_prod_util.h"
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "base/time.h"
#include "net/base/net_log.h"
#include "net/base/request_priority.h"
#include "net/base/ssl_config_service.h"
#include "net/http/http_auth.h"
#include "net/http/http_request_headers.h"
#include "net/http/http_response_info.h"
#include "net/http/http_stream_factory.h"
#include "net/http/http_transaction.h"
#include "net/proxy/proxy_service.h"

namespace net {

class HttpAuthController;
class HttpNetworkSession;
class HttpStreamBase;
class HttpStreamRequest;
class IOBuffer;
struct HttpRequestInfo;

class NET_EXPORT_PRIVATE HttpNetworkTransaction
    : public HttpTransaction,
      public HttpStreamRequest::Delegate {
 public:
  explicit HttpNetworkTransaction(HttpNetworkSession* session);

  virtual ~HttpNetworkTransaction();

  // HttpTransaction methods:
  virtual int Start(const HttpRequestInfo* request_info,
                    const CompletionCallback& callback,
                    const BoundNetLog& net_log) OVERRIDE;
  virtual int RestartIgnoringLastError(
      const CompletionCallback& callback) OVERRIDE;
  virtual int RestartWithCertificate(
      X509Certificate* client_cert,
      const CompletionCallback& callback) OVERRIDE;
  virtual int RestartWithAuth(const AuthCredentials& credentials,
                              const CompletionCallback& callback) OVERRIDE;
  virtual bool IsReadyToRestartForAuth() OVERRIDE;

  virtual int Read(IOBuffer* buf,
                   int buf_len,
                   const CompletionCallback& callback) OVERRIDE;
  virtual void StopCaching() OVERRIDE {}
  virtual void DoneReading() OVERRIDE {}
  virtual const HttpResponseInfo* GetResponseInfo() const OVERRIDE;
  virtual LoadState GetLoadState() const OVERRIDE;
  virtual UploadProgress GetUploadProgress() const OVERRIDE;

  // HttpStreamRequest::Delegate methods:
  virtual void OnStreamReady(const SSLConfig& used_ssl_config,
                             const ProxyInfo& used_proxy_info,
                             HttpStreamBase* stream) OVERRIDE;
  virtual void OnStreamFailed(int status,
                              const SSLConfig& used_ssl_config) OVERRIDE;
  virtual void OnCertificateError(int status,
                                  const SSLConfig& used_ssl_config,
                                  const SSLInfo& ssl_info) OVERRIDE;
  virtual void OnNeedsProxyAuth(
      const HttpResponseInfo& response_info,
      const SSLConfig& used_ssl_config,
      const ProxyInfo& used_proxy_info,
      HttpAuthController* auth_controller) OVERRIDE;
  virtual void OnNeedsClientAuth(const SSLConfig& used_ssl_config,
                                 SSLCertRequestInfo* cert_info) OVERRIDE;
  virtual void OnHttpsProxyTunnelResponse(const HttpResponseInfo& response_info,
                                          const SSLConfig& used_ssl_config,
                                          const ProxyInfo& used_proxy_info,
                                          HttpStreamBase* stream) OVERRIDE;

  virtual bool GetLoadTimingInfo(
      LoadTimingInfo* load_timing_info) const OVERRIDE;

 private:
  FRIEND_TEST_ALL_PREFIXES(HttpNetworkTransactionSpdy2Test,
                           ResetStateForRestart);
  FRIEND_TEST_ALL_PREFIXES(HttpNetworkTransactionSpdy3Test,
                           ResetStateForRestart);
  FRIEND_TEST_ALL_PREFIXES(SpdyNetworkTransactionSpdy2Test,
                           WindowUpdateReceived);
  FRIEND_TEST_ALL_PREFIXES(SpdyNetworkTransactionSpdy2Test,
                           WindowUpdateSent);
  FRIEND_TEST_ALL_PREFIXES(SpdyNetworkTransactionSpdy2Test,
                           WindowUpdateOverflow);
  FRIEND_TEST_ALL_PREFIXES(SpdyNetworkTransactionSpdy2Test,
                           FlowControlStallResume);
  FRIEND_TEST_ALL_PREFIXES(SpdyNetworkTransactionSpdy3Test,
                           WindowUpdateReceived);
  FRIEND_TEST_ALL_PREFIXES(SpdyNetworkTransactionSpdy3Test,
                           WindowUpdateSent);
  FRIEND_TEST_ALL_PREFIXES(SpdyNetworkTransactionSpdy3Test,
                           WindowUpdateOverflow);
  FRIEND_TEST_ALL_PREFIXES(SpdyNetworkTransactionSpdy3Test,
                           FlowControlStallResume);
  FRIEND_TEST_ALL_PREFIXES(SpdyNetworkTransactionSpdy3Test,
                           FlowControlStallResumeAfterSettings);
  FRIEND_TEST_ALL_PREFIXES(SpdyNetworkTransactionSpdy3Test,
                           FlowControlNegativeSendWindowSize);

  enum State {
    STATE_CREATE_STREAM,
    STATE_CREATE_STREAM_COMPLETE,
    STATE_INIT_STREAM,
    STATE_INIT_STREAM_COMPLETE,
    STATE_GENERATE_PROXY_AUTH_TOKEN,
    STATE_GENERATE_PROXY_AUTH_TOKEN_COMPLETE,
    STATE_GENERATE_SERVER_AUTH_TOKEN,
    STATE_GENERATE_SERVER_AUTH_TOKEN_COMPLETE,
    STATE_INIT_REQUEST_BODY,
    STATE_INIT_REQUEST_BODY_COMPLETE,
    STATE_BUILD_REQUEST,
    STATE_BUILD_REQUEST_COMPLETE,
    STATE_SEND_REQUEST,
    STATE_SEND_REQUEST_COMPLETE,
    STATE_READ_HEADERS,
    STATE_READ_HEADERS_COMPLETE,
    STATE_READ_BODY,
    STATE_READ_BODY_COMPLETE,
    STATE_DRAIN_BODY_FOR_AUTH_RESTART,
    STATE_DRAIN_BODY_FOR_AUTH_RESTART_COMPLETE,
    STATE_NONE
  };

  bool is_https_request() const;

  void DoCallback(int result);
  void OnIOComplete(int result);

  // Runs the state transition loop.
  int DoLoop(int result);

  // Each of these methods corresponds to a State value.  Those with an input
  // argument receive the result from the previous state.  If a method returns
  // ERR_IO_PENDING, then the result from OnIOComplete will be passed to the
  // next state method as the result arg.
  int DoCreateStream();
  int DoCreateStreamComplete(int result);
  int DoInitStream();
  int DoInitStreamComplete(int result);
  int DoGenerateProxyAuthToken();
  int DoGenerateProxyAuthTokenComplete(int result);
  int DoGenerateServerAuthToken();
  int DoGenerateServerAuthTokenComplete(int result);
  int DoInitRequestBody();
  int DoInitRequestBodyComplete(int result);
  int DoBuildRequest();
  int DoBuildRequestComplete(int result);
  int DoSendRequest();
  int DoSendRequestComplete(int result);
  int DoReadHeaders();
  int DoReadHeadersComplete(int result);
  int DoReadBody();
  int DoReadBodyComplete(int result);
  int DoDrainBodyForAuthRestart();
  int DoDrainBodyForAuthRestartComplete(int result);

  void BuildRequestHeaders(bool using_proxy);

  // Record histogram of time until first byte of header is received.
  void LogTransactionConnectedMetrics();

  // Record histogram of latency (durations until last byte received).
  void LogTransactionMetrics() const;

  // Writes a log message to help debugging in the field when we block a proxy
  // response to a CONNECT request.
  void LogBlockedTunnelResponse(int response_code) const;

  // Called to handle a client certificate request.
  int HandleCertificateRequest(int error);

  // Called to possibly recover from an SSL handshake error.  Sets next_state_
  // and returns OK if recovering from the error.  Otherwise, the same error
  // code is returned.
  int HandleSSLHandshakeError(int error);

  // Called to possibly recover from the given error.  Sets next_state_ and
  // returns OK if recovering from the error.  Otherwise, the same error code
  // is returned.
  int HandleIOError(int error);

  // Gets the response headers from the HttpStream.
  HttpResponseHeaders* GetResponseHeaders() const;

  // Called when we reached EOF or got an error.  Returns true if we should
  // resend the request.  |error| is OK when we reached EOF.
  bool ShouldResendRequest(int error) const;

  // Resets the connection and the request headers for resend.  Called when
  // ShouldResendRequest() is true.
  void ResetConnectionAndRequestForResend();

  // Decides the policy when the connection is closed before the end of headers
  // has been read. This only applies to reading responses, and not writing
  // requests.
  int HandleConnectionClosedBeforeEndOfHeaders();

  // Sets up the state machine to restart the transaction with auth.
  void PrepareForAuthRestart(HttpAuth::Target target);

  // Called when we don't need to drain the response body or have drained it.
  // Resets |connection_| unless |keep_alive| is true, then calls
  // ResetStateForRestart.  Sets |next_state_| appropriately.
  void DidDrainBodyForAuthRestart(bool keep_alive);

  // Resets the members of the transaction so it can be restarted.
  void ResetStateForRestart();

  // Resets the members of the transaction, except |stream_|, which needs
  // to be maintained for multi-round auth.
  void ResetStateForAuthRestart();

  // Returns true if we should try to add a Proxy-Authorization header
  bool ShouldApplyProxyAuth() const;

  // Returns true if we should try to add an Authorization header.
  bool ShouldApplyServerAuth() const;

  // Handles HTTP status code 401 or 407.
  // HandleAuthChallenge() returns a network error code, or OK on success.
  // May update |pending_auth_target_| or |response_.auth_challenge|.
  int HandleAuthChallenge();

  // Returns true if we have auth credentials for the given target.
  bool HaveAuth(HttpAuth::Target target) const;

  // Get the {scheme, host, path, port} for the authentication target
  GURL AuthURL(HttpAuth::Target target) const;

  // Debug helper.
  static std::string DescribeState(State state);

  scoped_refptr<HttpAuthController>
      auth_controllers_[HttpAuth::AUTH_NUM_TARGETS];

  // Whether this transaction is waiting for proxy auth, server auth, or is
  // not waiting for any auth at all. |pending_auth_target_| is read and
  // cleared by RestartWithAuth().
  HttpAuth::Target pending_auth_target_;

  CompletionCallback io_callback_;
  CompletionCallback callback_;

  scoped_refptr<HttpNetworkSession> session_;

  BoundNetLog net_log_;
  const HttpRequestInfo* request_;
  HttpResponseInfo response_;

  // |proxy_info_| is the ProxyInfo used by the HttpStreamRequest.
  ProxyInfo proxy_info_;

  scoped_ptr<HttpStreamRequest> stream_request_;
  scoped_ptr<HttpStreamBase> stream_;

  // True if we've validated the headers that the stream parser has returned.
  bool headers_valid_;

  // True if we've logged the time of the first response byte.  Used to
  // prevent logging across authentication activity where we see multiple
  // responses.
  bool logged_response_time_;

  SSLConfig server_ssl_config_;
  SSLConfig proxy_ssl_config_;

  HttpRequestHeaders request_headers_;

  // The size in bytes of the buffer we use to drain the response body that
  // we want to throw away.  The response body is typically a small error
  // page just a few hundred bytes long.
  static const int kDrainBodyBufferSize = 1024;

  // User buffer and length passed to the Read method.
  scoped_refptr<IOBuffer> read_buf_;
  int read_buf_len_;

  // The time the Start method was called.
  base::Time start_time_;

  // When the transaction started / finished sending the request, including
  // the body, if present.
  base::TimeTicks send_start_time_;
  base::TimeTicks send_end_time_;

  // When the transaction finished reading the request headers.
  base::TimeTicks receive_headers_end_;

  // The next state in the state machine.
  State next_state_;

  // True when the tunnel is in the process of being established - we can't
  // read from the socket until the tunnel is done.
  bool establishing_tunnel_;

  DISALLOW_COPY_AND_ASSIGN(HttpNetworkTransaction);
};

}  // namespace net

#endif  // NET_HTTP_HTTP_NETWORK_TRANSACTION_H_