Add NetLog support to UDP sockets.

net/udp/udp_data_transfer_param.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_UDP_UDP_DATA_TRANSFER_PARAM_H_
+#define NET_UDP_UDP_DATA_TRANSFER_PARAM_H_
+#pragma once
+
+#include <string>
+
+#include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
+#include "net/base/net_log.h"
+
+namespace net {
+
+class IPEndPoint;
+
+// NetLog parameter to describe a UDP receive/send event.  Each event has a
+// byte count, and may optionally have transferred bytes and an IPEndPoint as
+// well.
+class UDPDataTransferNetLogParam : public NetLog::EventParameters {
+ public:
+  // |bytes| are only logged when |log_bytes| is non-NULL.
+  // |address| may be NULL.
+  UDPDataTransferNetLogParam(int byte_count, const char* bytes, bool log_bytes,
+                             const IPEndPoint* address);
+  virtual ~UDPDataTransferNetLogParam();
+
+  virtual base::Value* ToValue() const OVERRIDE;
+
+ private:
+  const int byte_count_;
+  const std::string hex_encoded_bytes_;

[Sergey Ulanov, 2011/10/13 04:01:54]

Do we need to store this here. This object is created every time we send/receive
UDP packet, so it's better to make it as light as possible.

[mmenke, 2011/10/13 14:37:23]

These may be accessed on other threads, after the destruction of all underlying
objects.  Since we only use this field when "log all bytes" is enabled, which is
pretty much never, unless we're manually investigating a particular failure,
it's not as bad as it sounds.

+  scoped_ptr<IPEndPoint> address_;

[Sergey Ulanov, 2011/10/13 04:01:54]

Does this need to be a pointer? Can we store it by value?
I think ideally this should be a ref-counted object to avoid copying the address
for every event.

[mmenke, 2011/10/13 14:37:23]

We'll access it on another thread, so we can't do it safely, since IPEndPoints
are mutable.

+};
+
+}  // namespace net
+
+#endif  // NET_BASE_ADDRESS_LIST_NET_LOG_PARAM_H_