UDP: Windows implementation using non-blocking IO

net/udp/udp_socket_win.h

 // 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_UDP_UDP_SOCKET_WIN_H_
 #define NET_UDP_UDP_SOCKET_WIN_H_
 
 #include <qos2.h>
 #include <winsock2.h>
 
@@ skipping 156 matching lines @@
   // other applications on the same host. See MSDN: http://goo.gl/6vqbj
   int SetMulticastLoopbackMode(bool loopback);
 
   // Sets the differentiated services flags on outgoing packets. May not
   // do anything on some platforms.
   int SetDiffServCodePoint(DiffServCodePoint dscp);
 
   // Resets the thread to be used for thread-safety checks.
   void DetachFromThread();
 
+  // This class by default uses overlapped IO. Call this method before Open()
+  // to switch to non-blocking IO.
+  void UseNonBlockingIO();
+
  private:
   enum SocketOptions {
     SOCKET_OPTION_MULTICAST_LOOP = 1 << 0
   };
 
   class Core;
 
   void DoReadCallback(int rv);
   void DoWriteCallback(int rv);
-  void DidCompleteRead();
-  void DidCompleteWrite();
+
+  // Version for using overlapped IO.
+  void DidCompleteReadOverlapped();
+  void DidCompleteWriteOverlapped();
+
+  // Version for using non-blocking IO.
+  void DidCompleteReadNonBlocking();
+  void DidCompleteWriteNonBlocking();
 
   // Handles stats and logging. |result| is the number of bytes transferred, on
   // success, or the net error code on failure. LogRead retrieves the address
   // from |recv_addr_storage_|, while LogWrite takes it as an optional argument.
   void LogRead(int result, const char* bytes) const;
   void LogWrite(int result, const char* bytes, const IPEndPoint* address) const;
 
   // Same as SendTo(), except that address is passed by pointer
   // instead of by reference. It is called from Write() with |address|
   // set to NULL.
   int SendToOrWrite(IOBuffer* buf,
                     int buf_len,
                     const IPEndPoint* address,
                     const CompletionCallback& callback);
 
   int InternalConnect(const IPEndPoint& address);
-  int InternalRecvFrom(IOBuffer* buf, int buf_len, IPEndPoint* address);
-  int InternalSendTo(IOBuffer* buf, int buf_len, const IPEndPoint* address);
+
+  // Version for using overlapped IO.
+  int InternalRecvFromOverlapped(IOBuffer* buf,
+                                 int buf_len,
+                                 IPEndPoint* address);
+  int InternalSendToOverlapped(IOBuffer* buf,
+                               int buf_len,
+                               const IPEndPoint* address);
+
+  // Version for using non-blocking IO.
+  int InternalRecvFromNonBlocking(IOBuffer* buf,
+                                  int buf_len,
+                                  IPEndPoint* address);
+  int InternalSendToNonBlocking(IOBuffer* buf,
+                                int buf_len,
+                                const IPEndPoint* address);
 
   // Applies |socket_options_| to |socket_|. Should be called before
   // Bind().
   int SetMulticastOptions();
   int DoBind(const IPEndPoint& address);
   // Binds to a random port on |address|.
   int RandomBind(const IPAddressNumber& address);
 
   // Attempts to convert the data in |recv_addr_storage_| and |recv_addr_len_|
   // to an IPEndPoint and writes it to |address|. Returns true on success.
@@ skipping 24 matching lines @@
   // These are mutable since they're just cached copies to make
   // GetPeerAddress/GetLocalAddress smarter.
   mutable scoped_ptr<IPEndPoint> local_address_;
   mutable scoped_ptr<IPEndPoint> remote_address_;
 
   // The core of the socket that can live longer than the socket itself. We pass
   // resources to the Windows async IO functions and we have to make sure that
   // they are not destroyed while the OS still references them.
   scoped_refptr<Core> core_;
 
+  bool non_blocking_reads_initialized_;
+  bool non_blocking_writes_initialized_;
+
   IPEndPoint* recv_from_address_;
 
   // Cached copy of the current address we're sending to, if any.  Used for
   // logging.
   scoped_ptr<IPEndPoint> send_to_address_;
 
   // External callback; called when read is complete.
   CompletionCallback read_callback_;
 
   // External callback; called when write is complete.
   CompletionCallback write_callback_;
 
   BoundNetLog net_log_;
 
   // QWAVE data. Used to set DSCP bits on outgoing packets.
   HANDLE qos_handle_;
   QOS_FLOWID qos_flow_id_;
 
+  // True if overlapp IO is used.
+  bool use_overlapped_io_;
+
   DISALLOW_COPY_AND_ASSIGN(UDPSocketWin);
 };
 
 //-----------------------------------------------------------------------------
 
 // QWAVE (Quality Windows Audio/Video Experience) is the latest windows
 // library for setting packet priorities (and other things). Unfortunately,
 // Microsoft has decided that setting the DSCP bits with setsockopt() no
 // longer works, so we have to use this API instead.
 // This class is meant to be used as a singleton. It exposes a few dynamically
@@ skipping 43 matching lines @@
   SetFlowFn set_flow_func_;
 
   FRIEND_TEST_ALL_PREFIXES(UDPSocketTest, SetDSCPFake);
   DISALLOW_COPY_AND_ASSIGN(QwaveAPI);
 };
 
 
 }  // namespace net
 
 #endif  // NET_UDP_UDP_SOCKET_WIN_H_