UDP: Windows implementation using non-blocking IO

net/udp/udp_socket_win.h

Index: net/udp/udp_socket_win.h
diff --git a/net/udp/udp_socket_win.h b/net/udp/udp_socket_win.h
index 6f0ec2ccbf142222b9fb41a3348fe1a30fa011db..6d60cdffdef7e39ce66b118237a4a47f748debcc 100644
--- a/net/udp/udp_socket_win.h
+++ b/net/udp/udp_socket_win.h
@@ -174,6 +174,10 @@ class NET_EXPORT UDPSocketWin : NON_EXPORTED_BASE(public base::NonThreadSafe) {
   // 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
@@ -183,8 +187,14 @@ class NET_EXPORT UDPSocketWin : NON_EXPORTED_BASE(public base::NonThreadSafe) {
 
   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
@@ -201,8 +211,22 @@ class NET_EXPORT UDPSocketWin : NON_EXPORTED_BASE(public base::NonThreadSafe) {
                     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().
@@ -247,6 +271,9 @@ class NET_EXPORT UDPSocketWin : NON_EXPORTED_BASE(public base::NonThreadSafe) {
   // 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
@@ -265,6 +292,9 @@ class NET_EXPORT UDPSocketWin : NON_EXPORTED_BASE(public base::NonThreadSafe) {
   HANDLE qos_handle_;
   QOS_FLOWID qos_flow_id_;
 
+  // True if overlapp IO is used.
+  bool use_overlapped_io_;
+
   DISALLOW_COPY_AND_ASSIGN(UDPSocketWin);
 };