Revert 113282 - Isolates generic DnsClient from AsyncHostResolver.

net/dns/dns_response.h

Index: net/dns/dns_response.h
===================================================================
--- net/dns/dns_response.h	(revision 113383)
+++ net/dns/dns_response.h	(working copy)
@@ -6,109 +6,43 @@
 #define NET_DNS_DNS_RESPONSE_H_
 #pragma once
 
-#include <string>
-
-#include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
-#include "base/string_piece.h"
 #include "net/base/net_export.h"
 #include "net/base/net_util.h"
 
-namespace net {
+namespace net{
 
 class DnsQuery;
 class IOBufferWithSize;
 
-namespace dns_protocol {
-struct Header;
-}
-
-// Parsed resource record.
-struct NET_EXPORT_PRIVATE DnsResourceRecord {
-  std::string name;  // in dotted form
-  uint16 type;
-  uint16 klass;
-  uint32 ttl;
-  base::StringPiece rdata;  // points to the original response buffer
-};
-
-// Iterator to walk over resource records of the DNS response packet.
-class NET_EXPORT_PRIVATE DnsRecordParser {
- public:
-  // Construct an uninitialized iterator.
-  DnsRecordParser();
-
-  // Construct an iterator to process the |packet| of given |length|.
-  // |offset| points to the beginning of the answer section.
-  DnsRecordParser(const void* packet, size_t length, size_t offset);
-
-  // Returns |true| if initialized.
-  bool IsValid() const { return packet_ != NULL; }
-
-  // Returns |true| if no more bytes remain in the packet.
-  bool AtEnd() const { return cur_ == packet_ + length_; }
-
-  // Parses a (possibly compressed) DNS name from the packet starting at
-  // |pos|. Stores output (even partial) in |out| unless |out| is NULL. |out|
-  // is stored in the dotted form, e.g., "example.com". Returns number of bytes
-  // consumed or 0 on failure.
-  // This is exposed to allow parsing compressed names within RRDATA for TYPEs
-  // such as NS, CNAME, PTR, MX, SOA.
-  // See RFC 1035 section 4.1.4.
-  int ParseName(const void* pos, std::string* out) const;
-
-  // Parses the next resource record. Returns true if succeeded.
-  bool ParseRecord(DnsResourceRecord* record);
-
- private:
-  const char* packet_;
-  size_t length_;
-  // Current offset within the packet.
-  const char* cur_;
-};
-
-// Buffer-holder for the DNS response allowing easy access to the header fields
-// and resource records. After reading into |io_buffer| must call InitParse to
-// position the RR parser.
+// Represents on-the-wire DNS response as an object; allows extracting
+// records.
 class NET_EXPORT_PRIVATE DnsResponse {
  public:
   // Constructs an object with an IOBuffer large enough to read
   // one byte more than largest possible response, to detect malformed
-  // responses.
-  DnsResponse();
-  // Constructs response from |data|. Used for testing purposes only!
-  DnsResponse(const void* data, size_t length, size_t answer_offset);
+  // responses; |query| is a pointer to the DnsQuery for which |this|
+  // is supposed to be a response.
+  explicit DnsResponse(DnsQuery* query);
   ~DnsResponse();
 
   // Internal buffer accessor into which actual bytes of response will be
   // read.
   IOBufferWithSize* io_buffer() { return io_buffer_.get(); }
 
-  // Returns false if the packet is shorter than the header or does not match
-  // |query| id or question.
-  bool InitParse(int nbytes, const DnsQuery& query);
+  // Parses response of size nbytes and puts address into |ip_addresses|,
+  // returns net_error code in case of failure.
+  int Parse(int nbytes, IPAddressList* ip_addresses);
 
-  // Accessors for the header.
-  uint8 flags0() const;  // first byte of flags
-  uint8 flags1() const;  // second byte of flags excluding rcode
-  uint8 rcode() const;
-  int answer_count() const;
-
-  // Returns an iterator to the resource records in the answer section. Must be
-  // called after InitParse. The iterator is valid only in the scope of the
-  // DnsResponse.
-  DnsRecordParser Parser() const;
-
  private:
-  // Convenience for header access.
-  const dns_protocol::Header* header() const;
+  // 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_;
 
-  // Iterator constructed after InitParse positioned at the answer section.
-  DnsRecordParser parser_;
-
   DISALLOW_COPY_AND_ASSIGN(DnsResponse);
 };