WDL/jnetlib/asyncdns.h

   1 /*
   2 ** JNetLib
   3 ** Copyright (C) 2008 Cockos Inc
   4 ** Copyright (C) 2000-2001 Nullsoft, Inc.
   5 ** Author: Justin Frankel
   6 ** File: asyncdns.h - JNL portable asynchronous DNS interface
   7 ** License: see jnetlib.h
   8 **
   9 ** Usage:
  10 **   1. Create JNL_AsyncDNS object, optionally with the number of cache entries.
  11 **   2. call resolve() to resolve a hostname into an address. The return value of
  12 **      resolve is 0 on success (host successfully resolved), 1 on wait (meaning
  13 **      try calling resolve() with the same hostname in a few hundred milliseconds
  14 **      or so), or -1 on error (i.e. the host can't resolve).
  15 **   3. call reverse() to do reverse dns (ala resolve()).
  16 **   4. enjoy.
  17 */
  18
  19 #ifndef _ASYNCDNS_H_
  20 #define _ASYNCDNS_H_
  21
  22 #include <time.h>
  23
  24 #ifndef JNL_NO_DEFINE_INTERFACES
  25 class JNL_IAsyncDNS
  26 {
  27 public:
  28   virtual ~JNL_IAsyncDNS() { }
  29   virtual int resolve(const char *hostname, unsigned int *addr)=0; // return 0 on success, 1 on wait, -1 on unresolvable
  30   virtual int reverse(unsigned int addr, char *hostname)=0; // return 0 on success, 1 on wait, -1 on unresolvable. hostname must be at least 256 bytes.
  31 };
  32 #define JNL_AsyncDNS_PARENTDEF : public JNL_IAsyncDNS
  33 #else
  34 #define JNL_IAsyncDNS JNL_AsyncDNS
  35 #define JNL_AsyncDNS_PARENTDEF
  36 #endif
  37
  38
  39 #ifndef JNL_NO_IMPLEMENTATION
  40
  41 class JNL_AsyncDNS JNL_AsyncDNS_PARENTDEF
  42 {
  43 public:
  44   JNL_AsyncDNS(int max_cache_entries=64);
  45   ~JNL_AsyncDNS();
  46
  47   int resolve(const char *hostname, unsigned int *addr); // return 0 on success, 1 on wait, -1 on unresolvable
  48   int reverse(unsigned int addr, char *hostname); // return 0 on success, 1 on wait, -1 on unresolvable. hostname must be at least 256 bytes.
  49
  50 private:
  51   typedef struct
  52   {
  53     time_t last_used; // timestamp.
  54     char resolved;
  55     char mode; // 1=reverse
  56     char hostname[256];
  57     unsigned int addr;
  58   }
  59   cache_entry;
  60
  61   cache_entry *m_cache;
  62   int m_cache_size;
  63   volatile int m_thread_kill;
  64 #ifdef _WIN32
  65   HANDLE m_thread;
  66   static unsigned WINAPI _threadfunc(void *_d);
  67 #else
  68   pthread_t m_thread;
  69   static unsigned int _threadfunc(void *_d);
  70 #endif
  71   void makesurethreadisrunning(void);
  72
  73 };
  74 #endif // !JNL_NO_IMPLEMENTATION
  75
  76 #endif //_ASYNCDNS_H_