Add Socket::ReadIfReady()

net/socket/tcp_socket_posix.cc

 // 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.
 
 #include "net/socket/tcp_socket.h"
 
 #include <errno.h>
 #include <netinet/tcp.h>
 #include <sys/socket.h>
 
@@ skipping 271 matching lines @@
       base::Bind(&TCPSocketPosix::ReadCompleted,
                  // Grab a reference to |buf| so that ReadCompleted() can still
                  // use it when Read() completes, as otherwise, this transfers
                  // ownership of buf to socket.
                  base::Unretained(this), make_scoped_refptr(buf), callback));
   if (rv != ERR_IO_PENDING)
     rv = HandleReadCompleted(buf, rv);
   return rv;
 }
 
+int TCPSocketPosix::ReadIfReady(IOBuffer* buf,
+                                int buf_len,
+                                const CompletionCallback& callback) {
+  DCHECK(socket_);
+  DCHECK(!callback.is_null());
+
+  int rv = socket_->ReadIfReady(
+      buf, buf_len, base::Bind(&TCPSocketPosix::ReadIfReadyCompleted,
+                               base::Unretained(this), callback));
+  if (rv != ERR_IO_PENDING)
+    rv = HandleReadCompleted(buf, rv);
+  return rv;
+}
+
 int TCPSocketPosix::Write(IOBuffer* buf,
                           int buf_len,
                           const CompletionCallback& callback) {
   DCHECK(socket_);
   DCHECK(!callback.is_null());
 
   CompletionCallback write_callback =
       base::Bind(&TCPSocketPosix::WriteCompleted,
                  // Grab a reference to |buf| so that WriteCompleted() can still
                  // use it when Write() completes, as otherwise, this transfers
@@ skipping 278 matching lines @@
 
   net_log_.EndEvent(
       NetLogEventType::TCP_CONNECT,
       CreateNetLogSourceAddressCallback(storage.addr, storage.addr_len));
 }
 
 void TCPSocketPosix::ReadCompleted(const scoped_refptr<IOBuffer>& buf,
                                    const CompletionCallback& callback,
                                    int rv) {
   DCHECK_NE(ERR_IO_PENDING, rv);
+
   callback.Run(HandleReadCompleted(buf.get(), rv));
 }
 
+void TCPSocketPosix::ReadIfReadyCompleted(const CompletionCallback& callback,
+                                          int rv) {
+  DCHECK_NE(ERR_IO_PENDING, rv);
+  DCHECK_GE(OK, rv);
+
+  HandleReadCompletedHelper(rv);
+  callback.Run(rv);
+}
+
 int TCPSocketPosix::HandleReadCompleted(IOBuffer* buf, int rv) {
+  HandleReadCompletedHelper(rv);
+
+  if (rv < 0)
+    return rv;
+
+  // Notify the watcher only if at least 1 byte was read.
+  if (rv > 0)
+    NotifySocketPerformanceWatcher();
+
+  net_log_.AddByteTransferEvent(NetLogEventType::SOCKET_BYTES_RECEIVED, rv,
+                                buf->data());
+  NetworkActivityMonitor::GetInstance()->IncrementBytesReceived(rv);
+
+  return rv;
+}
+
+void TCPSocketPosix::HandleReadCompletedHelper(int rv) {
   if (tcp_fastopen_write_attempted_ && !tcp_fastopen_connected_) {
     // A TCP FastOpen connect-with-write was attempted. This read was a
     // subsequent read, which either succeeded or failed. If the read
     // succeeded, the socket is considered connected via TCP FastOpen.
     // If the read failed, TCP FastOpen is (conservatively) turned off for all
     // subsequent connections. TCP FastOpen status is recorded in both cases.
     // TODO (jri): This currently results in conservative behavior, where TCP
     // FastOpen is turned off on _any_ error. Implement optimizations,
     // such as turning off TCP FastOpen on more specific errors, and
     // re-attempting TCP FastOpen after a certain amount of time has passed.
     if (rv >= 0)
       tcp_fastopen_connected_ = true;
     else
       g_tcp_fastopen_has_failed = true;
     UpdateTCPFastOpenStatusAfterRead();
   }
 
   if (rv < 0) {
     net_log_.AddEvent(NetLogEventType::SOCKET_READ_ERROR,
                       CreateNetLogSocketErrorCallback(rv, errno));
-    return rv;
   }
-
-  // Notify the watcher only if at least 1 byte was read.
-  if (rv > 0)
-    NotifySocketPerformanceWatcher();
-
-  net_log_.AddByteTransferEvent(NetLogEventType::SOCKET_BYTES_RECEIVED, rv,
-                                buf->data());
-  NetworkActivityMonitor::GetInstance()->IncrementBytesReceived(rv);
-
-  return rv;
 }
 
 void TCPSocketPosix::WriteCompleted(const scoped_refptr<IOBuffer>& buf,
                                     const CompletionCallback& callback,
                                     int rv) {
   DCHECK_NE(ERR_IO_PENDING, rv);
   callback.Run(HandleWriteCompleted(buf.get(), rv));
 }
 
 int TCPSocketPosix::HandleWriteCompleted(IOBuffer* buf, int rv) {
@@ skipping 173 matching lines @@
     if (info.tcpi_rtt > 0) {
       *out_rtt = base::TimeDelta::FromMicroseconds(info.tcpi_rtt);
       return true;
     }
   }
 #endif  // defined(TCP_INFO)
   return false;
 }
 
 }  // namespace net