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       1                 :            : // Copyright (C) 2010  Internet Systems Consortium, Inc. ("ISC")
       2                 :            : //
       3                 :            : // Permission to use, copy, modify, and/or distribute this software for any
       4                 :            : // purpose with or without fee is hereby granted, provided that the above
       5                 :            : // copyright notice and this permission notice appear in all copies.
       6                 :            : //
       7                 :            : // THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
       8                 :            : // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
       9                 :            : // AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
      10                 :            : // INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
      11                 :            : // LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
      12                 :            : // OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
      13                 :            : // PERFORMANCE OF THIS SOFTWARE.
      14                 :            : 
      15                 :            : #ifndef __ADDRESS_REQUEST_CALLBACK_H
      16                 :            : #define __ADDRESS_REQUEST_CALLBACK_H
      17                 :            : 
      18                 :            : #include "asiolink.h"
      19                 :            : #include "nameserver_address.h"
      20                 :            : 
      21                 :            : namespace isc {
      22                 :            : namespace nsas {
      23                 :            : 
      24                 :            : /// \brief Callback When Address Obtained
      25                 :            : ///
      26                 :            : /// This is the callback object used to return an address of a nameserver to a
      27                 :            : /// caller.  It (or a subclass of it) is passed to the NSAS when a request is
      28                 :            : /// made for the address of a nameserver.  When an address is available,
      29                 :            : /// methods on the passed objects are called.
      30                 :            : ///
      31                 :            : /// Note that there is no guarantee as to when the methods are called; they
      32                 :            : /// could be called after the function call that made the address request has
      33                 :            : /// returned the caller.  Equally, the call could complete before that function
      34                 :            : /// call returns.  It is up to the caller to handle all cases.
      35                 :            : ///
      36                 :            : /// In terms of use, a shared pointer to this object is passed to the NSAS.
      37                 :            : /// The NSAS will store the object via a shared pointer and after the callback
      38                 :            : /// will delete the pointer.  Whether this results in the deletion of the
      39                 :            : /// callback object is up to the caller - if the caller wants to retain it
      40                 :            : /// they should keep the shared pointer.
      41                 :            : 
      42                 :       2032 : class AddressRequestCallback {
      43                 :            : public:
      44                 :            : 
      45                 :            :     /// Default constructor, copy contructor and assignment operator
      46                 :            :     /// are implicitly present and are OK.
      47                 :            : 
      48                 :            :     /// \brief Virtual Destructor
      49                 :          0 :     virtual ~AddressRequestCallback()
      50                 :       2029 :     {}
      51                 :            : 
      52                 :            :     /// \brief Success Callback
      53                 :            :     ///
      54                 :            :     /// This method is used when an address has been retrieved for the request.
      55                 :            :     ///
      56                 :            :     /// \param address Address to be used to access the nameserver.
      57                 :            :     virtual void success(const NameserverAddress& address) = 0;
      58                 :            : 
      59                 :            :     /// \brief Unreachable
      60                 :            :     ///
      61                 :            :     /// This method is called when a request is made for an address, but all
      62                 :            :     /// the addresses for the zone are marked as unreachable.  This may be
      63                 :            :     /// due to the NS records being unobtainable, or the A records for known
      64                 :            :     /// nameservers being unobtainable.
      65                 :            :     virtual void unreachable() = 0;
      66                 :            : 
      67                 :            : };
      68                 :            : 
      69                 :            : } // namespace nsas
      70                 :            : } // namespace isc
      71                 :            : 
      72                 :            : #endif // __ADDRESS_REQUEST_CALLBACK_H