Basic HTTP pipelining support

net/http/http_pipelined_connection_impl.h

+// Copyright (c) 2011 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_PIPELINED_CONNECTION_IMPL_H_
+#define NET_HTTP_HTTP_PIPELINED_CONNECTION_IMPL_H_
+#pragma once
+
+#include <map>
+#include <queue>
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/task.h"
+#include "net/base/completion_callback.h"
+#include "net/base/net_log.h"
+#include "net/base/ssl_config_service.h"
+#include "net/base/upload_data_stream.h"
+#include "net/http/http_pipelined_connection.h"
+#include "net/http/http_request_info.h"
+#include "net/proxy/proxy_info.h"
+
+namespace net {
+
+class ClientSocketHandle;
+class GrowableIOBuffer;
+class HttpPipelinedHost;

[mmenke, 2011/08/23 19:05:25]

nit:  No longer needed.

[James Simonsen, 2011/08/26 22:19:07]

Done.

+class HttpPipelinedStream;
+class HttpRequestHeaders;
+class HttpResponseInfo;
+class HttpStreamParser;
+class IOBuffer;
+class SSLCertRequestInfo;
+class SSLInfo;
+
+// This class manages all of the state for a single pipelined connection. It
+// tracks the order that HTTP requests are sent and enforces that the
+// subsequent reads occur in the appropriate order.
+//
+// If an error occurs related to pipelining, ERR_PIPELINE_EVICTION will be
+// returned to the client. This indicates the client should retry the request
+// without pipelining.
+class HttpPipelinedConnectionImpl : public HttpPipelinedConnection {
+ public:
+  HttpPipelinedConnectionImpl(ClientSocketHandle* connection,
+                              Owner* owner,
+                              const SSLConfig& used_ssl_config,
+                              const ProxyInfo& used_proxy_info,
+                              const BoundNetLog& net_log,
+                              bool was_npn_negotiated);
+  ~HttpPipelinedConnectionImpl();
+
+  // HttpPipelinedConnection interface.
+
+  // Used by HttpStreamFactoryImpl and friends.
+  HttpStream* CreateNewStream() OVERRIDE;
+
+  // Used by HttpPipelinedHost.
+  int depth() const OVERRIDE { return stream_state_map_.size(); }

[mmenke, 2011/08/23 19:05:25]

virtual should always be used with OVERRIDE.

[James Simonsen, 2011/08/26 22:19:07]

Done.

+  bool usable() const OVERRIDE { return usable_; }
+  bool active() const OVERRIDE { return active_; }
+
+  // Used by HttpStreamFactoryImpl.
+  const SSLConfig& used_ssl_config() const OVERRIDE { return used_ssl_config_; }
+  const ProxyInfo& used_proxy_info() const OVERRIDE { return used_proxy_info_; }
+  const NetLog::Source& source() const OVERRIDE { return net_log_.source(); }
+  bool was_npn_negotiated() const OVERRIDE { return was_npn_negotiated_; }
+
+  // Used by HttpPipelinedStream.
+  void OnStreamDeleted(int pipeline_id) OVERRIDE;
+
+  // Effective implementation of HttpStream. Note that we don't directly
+  // implement that interface. Instead, these functions will be called by the
+  // pass-through methods in HttpPipelinedStream.
+  void InitializeParser(int pipeline_id,
+                        const HttpRequestInfo* request,
+                        const BoundNetLog& net_log);
+
+  int SendRequest(int pipeline_id,
+                  const std::string& request_line,
+                  const HttpRequestHeaders& headers,
+                  UploadDataStream* request_body,
+                  HttpResponseInfo* response,
+                  CompletionCallback* callback);
+
+  int ReadResponseHeaders(int pipeline_id,
+                          CompletionCallback* callback);
+
+  int ReadResponseBody(int pipeline_id,
+                       IOBuffer* buf, int buf_len,
+                       CompletionCallback* callback);
+
+  void Close(int pipeline_id,
+             bool not_reusable);
+
+  uint64 GetUploadProgress(int pipeline_id) const;
+
+  HttpResponseInfo* GetResponseInfo(int pipeline_id);
+
+  bool IsResponseBodyComplete(int pipeline_id) const;
+
+  bool CanFindEndOfResponse(int pipeline_id) const;
+
+  bool IsMoreDataBuffered(int pipeline_id) const;
+
+  bool IsConnectionReused(int pipeline_id) const;
+
+  void SetConnectionReused(int pipeline_id);
+
+  void GetSSLInfo(int pipeline_id,
+                  SSLInfo* ssl_info);
+
+  void GetSSLCertRequestInfo(int pipeline_id,
+                             SSLCertRequestInfo* cert_request_info);
+
+ private:
+  enum StreamState {
+    STREAM_CREATED,
+    STREAM_BOUND,
+    STREAM_SENT,
+    STREAM_CLOSED,
+    STREAM_UNUSED,
+  };
+  enum SendRequestState {
+    SEND_STATE_NEXT_REQUEST,
+    SEND_STATE_COMPLETE,
+    SEND_STATE_NONE,
+    SEND_STATE_UNUSABLE,
+  };
+  enum ReadHeadersState {
+    READ_STATE_NEXT_HEADERS,
+    READ_STATE_COMPLETE,
+    READ_STATE_WAITING_FOR_CLOSE,
+    READ_STATE_STREAM_CLOSED,
+    READ_STATE_NONE,
+    READ_STATE_UNUSABLE,
+  };
+
+  struct DeferredSendRequest {
+    int pipeline_id;
+    std::string request_line;
+    HttpRequestHeaders headers;
+    UploadDataStream* request_body;
+    HttpResponseInfo* response;
+    CompletionCallback* callback;
+  };
+
+  // Called after the first request is processed, allowing the rest of this
+  // pipeline to fill up with any pending requests.
+  void FillPipeline();
+
+  // Responsible for sending one request at a time and waiting until each
+  // comepletes.
+  int DoSendRequestLoop(int result);
+
+  // Called when an asynchronous Send() completes.
+  void OnSendIOCallback(int result);
+
+  // Sends the next deferred request. This may be called immediately after
+  // SendRequest(), or it may be in a new task after a prior send completes in
+  // DoSendComplete().

[mmenke, 2011/08/23 19:05:25]

Thanks for adding all these comments.  Makes it much easier to follow the flow
of the code.

+  int DoSendNextRequest(int result);
+
+  // Notifies the user that the send has completed. This may be called directly
+  // after SendRequest() for a synchronous request, or it may be called in
+  // response to OnSendIOCallback for an asynchronous request.
+  int DoSendComplete(int result);
+
+  // Evicts all unsent deferred requests. This is called if there is a Send()
+  // error or one of our sockets informs us the connection is no longer

[mmenke, 2011/08/23 19:05:25]

nit:  "One of our streams"

[James Simonsen, 2011/08/26 22:19:07]

Done.

+  // reusable.
+  int DoEvictPendingSendRequests(int result);
+
+  // Ensures that only the active request's HttpPipelinedSocket can read from
+  // the underlying socket until it completes. A HttpPipelinedSocket informs us
+  // that it's done by calling Close().
+  int DoReadHeadersLoop(int result);
+
+  // Called when the pending asynchronous ReadResponseHeaders() completes.
+  void OnReadIOCallback(int result);
+
+  // Determines if the next response in the pipeline is ready to be read. A

[mmenke, 2011/08/23 19:05:25]

nit:  Remove "A" at end of line.

[James Simonsen, 2011/08/26 22:19:07]

Done.

+  // If it's ready, then we call ReadResponseHeaders() on the underlying parser.
+  // HttpPipelinedSocket indicates its readiness by calling
+  // ReadResponseHeaders(). This function may be called immediately after
+  // ReadResponseHeaders(), or it may be called in a new task after a previous
+  // HttpPipelinedSocket finishes its work.
+  int DoReadNextHeaders(int result);
+
+  // Notifies the user that reading the headers has completed. This may happen
+  // directly after DoReadNextHeaders() if the response is already available.
+  // Otherwise, it is called in response to OnReadIOCallback().
+  int DoReadHeadersComplete(int result);
+
+  // This is a holding state. It does not do anything, except exit the
+  // DoReadHeadersLoop(). It is called after DoReadHeadersComplete().
+  int DoReadWaitingForClose(int result);
+
+  // Cleans up the state associated with the active request. Invokes
+  // DoReadNextHeaders() in a new task to start the next response. This is
+  // called after the active request's HttpPipelinedSocket calls Close().
+  int DoReadStreamClosed();
+
+  // Removes all pending ReadResponseHeaders() requests from the queue. This may
+  // happen if there is an error with the pipeline or one of our
+  // HttpPipelinedSockets indicates the connection was suddenly closed.
+  int DoEvictPendingReadHeaders(int result);
+
+  // Invokes the user's callback in response to one of our own IO callbacks
+  // being invoked. This may be used for either Send or Read callbacks.
+  void FireUserCallback(CompletionCallback* callback, int result);
+
+  Owner* owner_;
+  scoped_ptr<ClientSocketHandle> connection_;
+  SSLConfig used_ssl_config_;
+  ProxyInfo used_proxy_info_;
+  BoundNetLog net_log_;
+  bool was_npn_negotiated_;
+  scoped_refptr<GrowableIOBuffer> read_buf_;
+  int next_pipeline_id_;
+  bool active_;
+  bool usable_;
+  ScopedRunnableMethodFactory<HttpPipelinedConnectionImpl> method_factory_;
+
+  typedef std::map<int, StreamState> StreamStateMap;
+  StreamStateMap stream_state_map_;
+  typedef std::map<int, HttpStreamParser*> ParserMap;
+  ParserMap parser_map_;
+
+  std::queue<int> request_order_;
+
+  std::queue<DeferredSendRequest> deferred_request_queue_;
+  SendRequestState send_next_state_;
+  CompletionCallbackImpl<HttpPipelinedConnectionImpl> send_io_callback_;
+  CompletionCallback* send_user_callback_;
+
+  ReadHeadersState read_next_state_;
+  CompletionCallbackImpl<HttpPipelinedConnectionImpl> read_io_callback_;
+  CompletionCallback* read_user_callback_;
+  typedef std::map<int, CompletionCallback*> CallbackMap;
+  CallbackMap callback_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(HttpPipelinedConnectionImpl);
+};
+
+}  // namespace net
+
+#endif  // NET_HTTP_HTTP_PIPELINED_CONNECTION_IMPL_H_