cdsa/cdsa_utilities/selector.h

   1 /*
   2  * Copyright (c) 2000-2001 Apple Computer, Inc. All Rights Reserved.
   3  *
   4  * The contents of this file constitute Original Code as defined in and are
   5  * subject to the Apple Public Source License Version 1.2 (the 'License').
   6  * You may not use this file except in compliance with the License. Please obtain
   7  * a copy of the License at http://www.apple.com/publicsource and read it before
   8  * using this file.
   9  *
  10  * This Original Code and all software distributed under the License are
  11  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
  12  * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
  13  * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
  14  * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
  15  * specific language governing rights and limitations under the License.
  16  */
  17
  18
  19 //
  20 // selector - I/O stream multiplexing
  21 //
  22 #ifndef _H_SELECTOR
  23 #define _H_SELECTOR
  24
  25 #include <Security/utilities.h>
  26 #include <Security/fdsel.h>
  27 #include "timeflow.h"
  28 #include <sys/types.h>
  29 #include <cstdio>
  30 #include <cstdarg>
  31 #include <map>
  32 #include <Security/debugging.h>
  33
  34
  35 namespace Security {
  36 namespace UnixPlusPlus {
  37
  38
  39 //
  40 // A Selector is an I/O dispatch facility that can supervise any number of "file descriptors",
  41 // each of which can perform I/O. Obviously this is geared towards the UNIX facility.
  42 //
  43 class Selector {
  44     class Client; friend class Client;
  45 public:
  46     Selector();
  47     virtual ~Selector();
  48
  49     //@@@ preliminary interface
  50     void operator () ();                // run just once (now)
  51     void operator () (Time::Absolute stopTime);
  52     void operator () (Time::Interval duration)
  53     { (*this)(Time::now() + duration); }
  54
  55     typedef unsigned int Type;
  56     static const Type none = 0x00;
  57     static const Type input = 0x01;
  58     static const Type output = 0x02;
  59     static const Type critical = 0x04;
  60     static const Type all = input | output | critical;
  61
  62 public:
  63     class Client {
  64         typedef Selector::Type Type;
  65         friend class Selector;
  66     public:
  67         Client() : mSelector(NULL) { }
  68         virtual void notify(int fd, Type type) = 0;
  69         virtual ~Client() { }
  70
  71         bool isActive() const           { return mSelector != NULL; }
  72
  73         static const Type input = Selector::input;
  74         static const Type output = Selector::output;
  75         static const Type critical = Selector::critical;
  76
  77     protected:
  78         void events(Type type)  { mSelector->set(mFd, type); mEvents = type; }
  79         Type events() const             { return mEvents; }
  80
  81         void enable(Type type)  { events(events() | type); }
  82         void disable(Type type) { events(events() & ~type); }
  83
  84         template <class Sel> Sel &selectorAs()
  85         { assert(mSelector); return safer_cast<Sel &>(*mSelector); }
  86
  87     private:
  88         int mFd;
  89         Selector *mSelector;
  90         Type mEvents;
  91     };
  92
  93     void add(int fd, Client &client, Type type = all);
  94     void remove(int fd);
  95     bool isEmpty() const                                { return clientMap.empty(); }
  96
  97 private:
  98     void set(int fd, Type type);                // (re)set mask for one client
  99
 100     void singleStep(Time::Interval maxWait);
 101
 102 private:
 103     unsigned int fdSetSize;                             // number of fd_masks allocated in FDSets
 104     int fdMin, fdMax;                                   // highest/lowest fds in use
 105     FDSet inSet, outSet, errSet;                // current in/out/error select masks
 106
 107 private:
 108     typedef map<int, Client *> ClientMap;
 109     ClientMap clientMap;
 110 };
 111
 112
 113 }       // end namespace UnixPlusPlus
 114 }       // end namespace Security
 115
 116
 117 #endif //_H_SELECTOR