Added DnsQuery class

net/base/dns_response.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_BASE_DNS_RESPONSE_H_
+#define NET_BASE_DNS_RESPONSE_H_
+#pragma once
+
+#include "net/base/dns_query.h"
+
+namespace net{
+
+class AddressList;
+
+// A class that encapsulates bits and pieces related to DNS response
+// processing.
+class DnsResponse {
+ public:
+  // Constructs an object with an IOBuffer large enough to read
+  // one byte more than largest possible response, to detect malformed
+  // responses; |query| is a pointer to the DnsQuery for which |this|
+  // is supposed to be a response.
+  explicit DnsResponse(DnsQuery* query);
+
+  // Internal buffer accessor into which actual bytes of response will be
+  // read.
+  IOBufferWithSize* io_buffer() { return io_buffer_.get(); }
+
+  // Parses response of size nbytes and puts address into |results|,
+  // returns net_error code in case of failure.
+  int Parse(int nbytes, AddressList* results);
+
+ private:
+  // The matching query; |this| is the response for |query_|.  We do not
+  // own it, lifetime of |this| should be within the limits of lifetime of
+  // |query_|.
+  const DnsQuery* const query_;
+
+  // Buffer into which response bytes are read.
+  scoped_refptr<IOBufferWithSize> io_buffer_;
+
+  DISALLOW_COPY_AND_ASSIGN(DnsResponse);
+};
+
+}  // namespace net
+
+#endif  // NET_BASE_DNS_RESPONSE_H_