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       1                 :            : // $Id: IOSource.h 6888 2009-08-20 18:23:11Z vern $
       2                 :            : //
       3                 :            : // Interface for classes providing/consuming data during Bro's main loop.
       4                 :            : 
       5                 :            : #ifndef iosource_h
       6                 :            : #define iosource_h
       7                 :            : 
       8                 :            : #include <list>
       9                 :            : #include "Timer.h"
      10                 :            : 
      11                 :            : using namespace std;
      12                 :            : 
      13                 :            : class IOSource {
      14                 :            : public:
      15                 :          7 :         IOSource()      { idle = closed = false; }
      16 [ #  # ][ #  # ]:          0 :         virtual ~IOSource()     {}
                 [ #  # ]
      17                 :            : 
      18                 :            :         // Returns true if source has nothing ready to process.
      19                 :      46095 :         bool IsIdle() const     { return idle; }
      20                 :            : 
      21                 :            :         // Returns true if more data is to be expected in the future.
      22                 :            :         // Otherwise, source may be removed.
      23                 :      42701 :         bool IsOpen() const     { return ! closed; }
      24                 :            : 
      25                 :            :         // Returns select'able fds (leaves args untouched if we don't have
      26                 :            :         // selectable fds).
      27                 :            :         virtual void GetFds(int* read, int* write, int* except) = 0;
      28                 :            : 
      29                 :            :         // The following two methods are only called when either IsIdle()
      30                 :            :         // returns false or select() on one of the fds indicates that there's
      31                 :            :         // data to process.
      32                 :            : 
      33                 :            :         // Returns timestamp (in global network time) associated with next
      34                 :            :         // data item.  If the source wants the data item to be processed
      35                 :            :         // with a local network time, it sets the argument accordingly.
      36                 :            :         virtual double NextTimestamp(double* network_time) = 0;
      37                 :            : 
      38                 :            :         // Processes and consumes next data item.
      39                 :            :         virtual void Process() = 0;
      40                 :            : 
      41                 :            :         // Returns tag of timer manager associated with last processed
      42                 :            :         // data item, nil for global timer manager.
      43                 :      64923 :         virtual TimerMgr::Tag* GetCurrentTag()  { return 0; }
      44                 :            : 
      45                 :            :         // Returns a descriptual tag for debugging.
      46                 :            :         virtual const char* Tag() = 0;
      47                 :            : 
      48                 :            : protected:
      49                 :            :         // Derived classed are to set this to true if they have gone dry
      50                 :            :         // temporarily.
      51                 :            :         bool idle;
      52                 :            : 
      53                 :            :         // Derived classed are to set this to true if they have gone dry
      54                 :            :         // permanently.
      55                 :            :         bool closed;
      56                 :            : };
      57                 :            : 
      58                 :            : class IOSourceRegistry {
      59                 :            : public:
      60                 :          3 :         IOSourceRegistry()      { call_count = 0; dont_counts = 0; }
      61                 :            :         ~IOSourceRegistry();
      62                 :            : 
      63                 :            :         // If dont_count is true, this source does not contribute to the
      64                 :            :         // number of IOSources returned by Size().  The effect is that
      65                 :            :         // if all sources but the non-counting ones have gone dry,
      66                 :            :         // processing will shut down.
      67                 :            :         void Register(IOSource* src, bool dont_count = false);
      68                 :            : 
      69                 :            :         // This may block for some time.
      70                 :            :         IOSource* FindSoonest(double* ts);
      71                 :            : 
      72                 :      21351 :         int Size() const        { return sources.size() - dont_counts; }
      73                 :            : 
      74                 :            :         // Terminate IOSource processing immediately by removing all
      75                 :            :         // sources (and therefore returning a Size() of zero).
      76                 :          0 :         void Terminate()        { RemoveAll(); }
      77                 :            : 
      78                 :            : protected:
      79                 :            :         // When looking for a source with something to process,
      80                 :            :         // every SELECT_FREQUENCY calls we will go ahead and
      81                 :            :         // block on a select().
      82                 :            :         static const int SELECT_FREQUENCY = 25;
      83                 :            : 
      84                 :            :         // Microseconds to wait in an empty select if no source is ready.
      85                 :            :         static const int SELECT_TIMEOUT = 50;
      86                 :            : 
      87                 :            :         void RemoveAll();
      88                 :            : 
      89                 :            :         unsigned int call_count;
      90                 :            :         int dont_counts;
      91                 :            : 
      92                 :            :         struct Source {
      93                 :            :                 IOSource* src;
      94                 :            :                 int fd_read;
      95                 :            :                 int fd_write;
      96                 :            :                 int fd_except;
      97                 :            :         };
      98                 :            : 
      99                 :            :         typedef list<Source*> SourceList;
     100                 :            :         SourceList sources;
     101                 :            : };
     102                 :            : 
     103                 :            : extern IOSourceRegistry io_sources;
     104                 :            : 
     105                 :            : #endif