WebSocketBasicStream framing logic

net/websockets/websocket_basic_stream.h

+// Copyright 2013 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_WEBSOCKETS_WEBSOCKET_BASIC_STREAM_H_
+#define NET_WEBSOCKETS_WEBSOCKET_BASIC_STREAM_H_
+
+#include <string>
+
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/scoped_vector.h"
+#include "net/websockets/websocket_frame_parser.h"
+#include "net/websockets/websocket_stream.h"
+
+namespace net {
+
+class ClientSocketHandle;
+class DrainableIOBuffer;
+class GrowableIOBuffer;
+class HttpRequestHeaders;
+class HttpResponseInfo;
+class IOBufferWithSize;
+struct WebSocketFrameChunk;
+
+// Implementation of WebSocketStream for non-multiplexed ws:// connections (or
+// the physical side of a multiplexed ws:// connection).
+class NET_EXPORT_PRIVATE WebSocketBasicStream : public WebSocketStream {
+ public:
+  // The type of a pointer to a function that generates a WebSocketMaskingKey.
+  typedef WebSocketMaskingKey (*WebSocketMaskingKeyGeneratorFunction)();
+
+  // This class should not normally be constructed directly; see
+  // WebSocketStream::CreateAndConnectStream.
+  explicit WebSocketBasicStream(scoped_ptr<ClientSocketHandle> connection);
+
+  // The destructor has to make sure the connection is closed when we finish so
+  // that it does not get returned to the pool.
+  virtual ~WebSocketBasicStream();
+
+  // Reads one or more frame chunks. See WebSocketStream for the full
+  // specifications of the behaviour.
+  virtual int ReadFrames(ScopedVector<WebSocketFrameChunk>* frame_chunks,
+                         const CompletionCallback& callback) OVERRIDE;
+
+  // Writes one or more frame chunks. Either writes everything or fails.
+  virtual int WriteFrames(ScopedVector<WebSocketFrameChunk>* frame_chunks,
+                          const CompletionCallback& callback) OVERRIDE;
+
+  // Closes the stream, cancelling all pending IO operations without calling the
+  // callbacks.
+  virtual void Close() OVERRIDE;
+
+  // Returns the optional sub-protocol that was negotiated with the server.
+  virtual std::string GetSubProtocol() const OVERRIDE;
+
+  // Returns the extensions that were negotiated with the server.
+  virtual std::string GetExtensions() const OVERRIDE;
+
+  // Writes WebSocket handshake request HTTP-style to the connection. Adds
+  // "Sec-WebSocket-Key" header; this should not be included in |headers|.
+  //
+  // "callback" will only be called if this method returns ERR_IO_PENDING.
+  //
+  // |response_info| must remain valid until the callback from
+  // ReadHandshakeResponse has been called.
+  virtual int SendHandshakeRequest(const GURL& url,
+                                   const HttpRequestHeaders& headers,
+                                   HttpResponseInfo* response_info,
+                                   const CompletionCallback& callback) OVERRIDE;
+
+  // Reads WebSocket handshake response from the connection. The callback
+  // function completes when the response headers have been completely
+  // received. Must be called after SendHandshakeRequest() completes (including
+  // the callback, if relevant). If the result was not available synchronously,
+  // then it will be passed to the callback. Note that the actual response info
+  // is passed into the HttpResponseInfo object that was passed to
+  // SendHandshakeResponse.
+  virtual int ReadHandshakeResponse(
+      const CompletionCallback& callback) OVERRIDE;
+
+  ////////////////////////////////////////////////////////////////////////////
+  // Methods for testing only.
+
+  // Creates a WebSocketBasicStream with the specified |connection|,
+  // |http_read_buffer|, |sub_protocol|, |extensions| and
+  // |key_generator_function|.
+  static scoped_ptr<WebSocketBasicStream> CreateWebSocketBasicStreamForTesting(
+      scoped_ptr<ClientSocketHandle> connection,
+      const scoped_refptr<GrowableIOBuffer>& http_read_buffer,
+      const std::string& sub_protocol,
+      const std::string& extensions,
+      WebSocketMaskingKeyGeneratorFunction key_generator_function);
+
+ private:
+  // The semantics of WriteFrames() are such that it only returns OK or calls
+  // the callback when everything is written or something has failed. But
+  // Socket::Write() can do partial writes, so this method wraps the call in a
+  // loop.
+  int WriteEverything(const scoped_refptr<DrainableIOBuffer>& buffer,
+                      const CompletionCallback& callback);
+
+  // Wraps the |callback| to continue writing until everything has been written.
+  void WriteDone(const scoped_refptr<DrainableIOBuffer>& buffer,
+                 const CompletionCallback& callback,
+                 int result);
+
+  // Called when a read completes. Parses the result and (unless no complete
+  // header has been received) calls |callback|.
+  void ReadDone(ScopedVector<WebSocketFrameChunk>* frame_chunks,
+                const CompletionCallback& callback,
+                int result);
+
+  // Storage for pending reads. All active WebSockets spend all the time with a
+  // call to ReadFrames() pending, so there is no benefit in trying to share
+  // this between sockets.
+  scoped_refptr<IOBufferWithSize> read_buffer_;
+
+  // The connection, wrapped in a ClientSocketHandle so that we can prevent it
+  // from being returned to the pool.
+  scoped_ptr<ClientSocketHandle> connection_;
+
+  // Only used during handshake. Some data may be left in this buffer after the
+  // handshake, in which case it will be picked up during the first call to
+  // ReadFrames().
+  scoped_refptr<GrowableIOBuffer> http_read_buffer_;
+
+  // This keeps the current parse state (including any incomplete headers) and
+  // parses frames.
+  WebSocketFrameParser parser_;
+
+  // The negotated sub-protocol, or empty for none.
+  std::string sub_protocol_;
+
+  // The extensions negotiated with the remote server.
+  std::string extensions_;
+
+  // This can be overridden in tests to make the output deterministic. We don't
+  // use a Callback here because a function pointer is faster and good enough
+  // for our purposes.
+  WebSocketMaskingKeyGeneratorFunction generate_websocket_masking_key_;
+};
+
+}  // namespace net
+
+#endif  // NET_WEBSOCKETS_WEBSOCKET_BASIC_STREAM_H_