Remove HttpTransactionWinHttp and the --winhttp command-line...

net/http/winhttp_request_throttle.h

-// Copyright (c) 2006-2008 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_WINHTTP_REQUEST_THROTTLE_H_
-#define NET_HTTP_WINHTTP_REQUEST_THROTTLE_H_
-
-#include <windows.h>
-#include <winhttp.h>
-
-#include <map>
-#include <string>
-
-#include "base/basictypes.h"
-#include "base/linked_ptr.h"
-#include "testing/gtest/include/gtest/gtest_prod.h"
-
-namespace net {
-
-// The WinHttpRequestThrottle class regulates the rate at which we call
-// WinHttpSendRequest, ensuring that at any time there are at most 6 WinHTTP
-// requests in progress for each server or proxy.
-//
-// The throttling is intended to cause WinHTTP to maintain at most 6
-// persistent HTTP connections with each server or proxy.  This works well in
-// most cases, except when making HTTPS requests via a proxy, in which case
-// WinHTTP may open much more than 6 connections to the proxy in spite of our
-// rate limiting.
-//
-// Because we identify a server by its hostname rather than its IP address,
-// we also can't distinguish between two different hostnames that resolve to
-// the same IP address.
-//
-// Although WinHTTP has the WINHTTP_OPTION_MAX_CONNS_PER_SERVER option to
-// limit the number of connections allowed per server, we can't use it
-// because it has two serious bugs:
-// 1. It causes WinHTTP to not close idle persistent connections, leaving
-//    many connections in the CLOSE_WAIT state.  This may cause system
-//    crashes (Blue Screen of Death) when VPN is used.
-// 2. It causes WinHTTP to crash intermittently in
-//    HTTP_REQUEST_HANDLE_OBJECT::OpenProxyTunnel_Fsm() if a proxy is used.
-// Therefore, we have to resort to throttling our WinHTTP requests to achieve
-// the same effect.
-//
-// Note on thread safety: The WinHttpRequestThrottle class is only used by
-// the IO thread, so it doesn't need to be protected with a lock.  The
-// drawback is that the time we mark a request done is only approximate.
-// We do that in the HttpTransactionWinHttp destructor, rather than in the
-// WinHTTP status callback upon receiving HANDLE_CLOSING.
-class WinHttpRequestThrottle {
- public:
-  WinHttpRequestThrottle() {}
-
-  virtual ~WinHttpRequestThrottle();
-
-  // Intended to be a near drop-in replacement of WinHttpSendRequest.
-  BOOL SubmitRequest(const std::string& server,
-                     HINTERNET request_handle,
-                     DWORD total_size,
-                     DWORD_PTR context);
-
-  // Called when a request failed or completed successfully.
-  void NotifyRequestDone(const std::string& server);
-
-  // Called from the HttpTransactionWinHttp destructor.
-  void RemoveRequest(const std::string& server,
-                     HINTERNET request_handle);
-
- protected:
-  // Unit tests can stub out this method in a derived class.
-  virtual BOOL SendRequest(HINTERNET request_handle,
-                           DWORD total_size,
-                           DWORD_PTR context,
-                           bool report_async_error);
-
- private:
-  FRIEND_TEST(WinHttpRequestThrottleTest, GarbageCollect);
-
-  class RequestQueue;
-
-  struct PerServerThrottle {
-    PerServerThrottle();
-    ~PerServerThrottle();
-
-    int num_requests;  // Number of requests in progress
-    linked_ptr<RequestQueue> request_queue;  // Requests waiting to be sent
-  };
-
-  typedef std::map<std::string, PerServerThrottle> ThrottleMap;
-
-  static const int kMaxConnectionsPerServer;
-  static const int kGarbageCollectionThreshold;
-
-  void GarbageCollect();
-
-  ThrottleMap throttles_;
-
-  DISALLOW_EVIL_CONSTRUCTORS(WinHttpRequestThrottle);
-};
-
-}  // namespace net
-
-#endif  // NET_HTTP_WINHTTP_REQUEST_THROTTLE_H_
-