Break the dependency of DnsQuery and DnsResponse from AddressList

net/base/dns_query.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_QUERY_H_
 #define NET_BASE_DNS_QUERY_H_
 #pragma once
 
 #include <string>
 
-#include "net/base/address_family.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_util.h"
 
 namespace net{
 
-// A class that encapsulates bits and pieces related to DNS request processing.
+// Represents on-the-wire DNS query message as an object.
 class DnsQuery {
  public:
-  // Constructs an object containing an IOBuffer with raw DNS query string
-  // for |hostname| with the given |address_family|; |port| is here due to
-  // legacy -- getaddrinfo() takes service name, which is mapped to some
-  // port and returns sockaddr_in structures with ports filled in, so do we
-  // -- look at DnsResponse::Parse() to see where it is used.
+  // Constructs a query message from |dns_name| which *MUST* be in a valid
+  // DNS name format, and |qtype| which must be either kDNS_A or kDNS_AAA.
 
   // Every generated object has a random ID, hence two objects generated
   // with the same set of constructor arguments are generally not equal;
   // there is a 1/2^16 chance of them being equal due to size of |id_|.
-  DnsQuery(const std::string& hostname, AddressFamily address_family, int port);
+  DnsQuery(const std::string& dns_name, uint16 qtype);
   ~DnsQuery();
 
-  // Returns true if the constructed object was valid.
-  bool IsValid() const { return io_buffer_.get() != NULL; }
+  // Clones |this| verbatim with ID field of the header regenerated.
+  DnsQuery* CloneWithNewId() const;
 
-  // DnsQuery field accessors.  These should only be called on an object
-  // for whom |IsValid| is true.
-  int port() const;
+  // DnsQuery field accessors.
   uint16 id() const;
   uint16 qtype() const;
-  AddressFamily address_family() const;
-  const std::string& hostname() const;
+
+  // Returns the size of the Question section of the query.  Used when
+  // matching the response.
+  size_t question_size() const;
+
+  // Returns pointer to the Question section of the query.  Used when
+  // matching the response.
+  const char* question_data() const;
 
   // IOBuffer accessor to be used for writing out the query.
-  IOBufferWithSize* io_buffer() const;
+  IOBufferWithSize* io_buffer() const { return io_buffer_; }
 
  private:
-  // Port to be used by corresponding DnsResponse when filling sockaddr_ins
-  // to be returned.
-  int port_;
+  // Copy constructor to be used only by CloneWithNewId; it's not public
+  // since there is a semantic difference -- this does not construct an
+  // exact copy!
+  DnsQuery(const DnsQuery& rhs);
 
-  // ID of the query.
-  uint16 id_;
+  // Not implemented; just to prevent the assignment.
+  void operator=(const DnsQuery&);
 
-  // Type of query, currently, either A or AAAA.
-  uint16 qtype_;
+  // Randomizes ID field of the query message.
+  void RandomizeId();
 
-  // Address family of the query; used when constructing new object from
-  // this one.
-  AddressFamily address_family_;
-
-  // Hostname that we are trying to resolve.
-  std::string hostname_;
+  // Size of the DNS name (*NOT* hostname) we are trying to resolve; used
+  // to calculate offsets.
+  size_t dns_name_size_;
 
   // Contains query bytes to be consumed by higher level Write() call.
   scoped_refptr<IOBufferWithSize> io_buffer_;
-
-  DISALLOW_COPY_AND_ASSIGN(DnsQuery);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_DNS_QUERY_H_