dnsinterface.hxx

这是国外的resip协议栈

#if !defined(RESIP_DNSINTERFACE_HXX)
#define RESIP_DNSINTERFACE_HXX 

#include <set>
#include <vector>

#include "rutil/TransportType.hxx"
#include "rutil/Data.hxx"
#include "rutil/Socket.hxx"
#include "rutil/BaseException.hxx"
#include "rutil/dns/DnsStub.hxx"
#include "rutil/dns/RRVip.hxx"
#include "resip/stack/TupleMarkManager.hxx"

namespace resip
{
class DnsHandler;
class DnsResultSink;
class DnsResult;
class Uri;
class Via;
//class ExternalDns;
class DnsRawSink;

class DnsInterface
{
   public:
      class Exception : public BaseException
      {
         public:
            Exception(const Data& msg, const Data& file, const int line) : BaseException(msg,file,line){}
            const char* name() const { return "DnsInterface::Exception"; }
      };

      // Used to create an asynchronous Dns Interface. Any lookup requests will
      // be queued for later processing. It is critical that the consumer of the
      // DnsResult be in the same thread that is processing the async results
      // since there is no locking on the DnsResult
      // Will throw DnsInterface::Exception if the Dns provider fails to initialize
      DnsInterface(DnsStub& dnsStub);

      virtual ~DnsInterface();

      //Data errorMessage(int status);

      // set the supported set of types that a UAC wishes to use
      void addTransportType(TransportType type, IpVersion version);
      
      // return if the client supports the specified service (e.g. SIP+D2T)
      bool isSupported(const Data& service);
     bool isSupported(TransportType t, IpVersion version);

      // this is used if NAPTR doesn't return anything to decide which SRV
      // records to query
      bool isSupportedProtocol(TransportType t);
      int supportedProtocols();

      
      //only call buildFdSet and process if requiresProcess is true.  
      bool requiresProcess();

      // adds the appropriate file descriptors to the fdset to allow a
      // select/poll call to be made 
      void buildFdSet(FdSet& fdset);

      // process any dns results back from the async dns library (e.g. ares). If
      // there are results to report, post an event to the fifo
      void process(FdSet& fdset);
      
      // For each of the following calls, immediately return a DnsResult to the
      // caller. If synchronous, the DnsResult is complete and may block for an
      // arbitrary amount of time. In the synchronous case, the transactionId is
      // not useful. If asynchronous, the DnsResult will be returned immediately
      // and is owned by the caller. If queries are outstanding, it is not valid
      // for the caller to delete the DnsResult.
      // 
      // First determine a transport.  Second, determine a set of ports and ip
      // addresses. These can be returned to the client by asking the DnsResult
      // for the next result in the form of a Transport:Tuple. The client can
      // continue to ask the DnsResult to return more tuples. If the tuples for
      // the current transport are exhausted, move on to the next preferred
      // transport (if there is one)

      DnsResult* createDnsResult(DnsHandler* handler=0);
      void lookup(DnsResult* res, const Uri& uri);

      //DnsResult* lookup(const Uri& url, DnsHandler* handler=0);
      //DnsResult* lookup(const Via& via, DnsHandler* handler=0);

      //void lookupRecords(const Data& target, unsigned short type, DnsRawSink* sink);
      //virtual void handleDnsRaw(ExternalDnsRawResult);
      TupleMarkManager& getMarkManager(){return mMarkManager;}

   protected: 
      // When complete or partial results are ready, call DnsHandler::process()
      // For synchronous DnsInterface, set to 0
      friend class DnsResult;
      DnsHandler* mHandler;
      std::set<Data> mSupportedNaptrs;
      typedef std::vector<std::pair<TransportType, IpVersion> > TransportMap;
      TransportMap mSupportedTransports;
      //std::set<TransportType> mSupportedTransportTypes;

      //ExternalDns* mDnsProvider;
      int mActiveQueryCount;      

      DnsStub& mDnsStub;
      RRVip mVip;
      TupleMarkManager mMarkManager;
};

}

#endif
//  Copyright (c) 2003, Jason Fischl
/* ====================================================================
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