src/EventLoop.cc

   1
   2 /*
   3  * $Id: EventLoop.cc,v 1.2 2006/08/12 01:43:10 robertc Exp $
   4  *
   5  * DEBUG: section 1     Main Loop
   6  * AUTHOR: Harvest Derived
   7  *
   8  * SQUID Web Proxy Cache          http://www.squid-cache.org/
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  10  *
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  18  *  sources; see the CREDITS file for full details.
  19  *
  20  *  This program is free software; you can redistribute it and/or modify
  21  *  it under the terms of the GNU General Public License as published by
  22  *  the Free Software Foundation; either version 2 of the License, or
  23  *  (at your option) any later version.
  24  *
  25  *  This program is distributed in the hope that it will be useful,
  26  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  27  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  28  *  GNU General Public License for more details.
  29  *
  30  *  You should have received a copy of the GNU General Public License
  31  *  along with this program; if not, write to the Free Software
  32  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  33  *
  34  */
  35
  36 #include "EventLoop.h"
  37
  38 EventLoop::EventLoop() : errcount(0), last_loop(false), timeService(NULL)
  39 {}
  40
  41 void
  42 EventLoop::prepareToRun()
  43 {
  44     last_loop = false;
  45     errcount = 0;
  46 }
  47
  48 void
  49 EventLoop::registerDispatcher(CompletionDispatcher *dispatcher)
  50 {
  51     dispatchers.push_back(dispatcher);
  52 }
  53
  54 void
  55 EventLoop::registerEngine(AsyncEngine *engine)
  56 {
  57     engines.push_back(engine);
  58 }
  59
  60 void
  61 EventLoop::run()
  62 {
  63     prepareToRun();
  64
  65     while (!runOnce())
  66
  67         ;
  68 }
  69
  70 bool
  71 EventLoop::runOnce()
  72 {
  73     bool result = true;
  74     bool error = false;
  75     int loop_delay = 10; /* 10 ms default delay */
  76
  77     for (engine_vector::iterator i = engines.begin();
  78             i != engines.end(); ++i) {
  79         int requested_delay;
  80         /* special case the last engine */
  81
  82         if (i - engines.end() != -1)
  83             requested_delay = (*i)->checkEvents(0);
  84         else /* last engine gets the delay */
  85             requested_delay = (*i)->checkEvents(loop_delay);
  86
  87         if (requested_delay < 0)
  88             switch (requested_delay) {
  89
  90             case AsyncEngine::EVENT_IDLE:
  91                 debugs(1, 9, "Engine " << *i << " is idle.");
  92                 break;
  93
  94             case AsyncEngine::EVENT_ERROR:
  95                 result = false;
  96                 error = true;
  97                 break;
  98
  99             default:
 100                 fatal_dump("unknown AsyncEngine result");
 101             }
 102         else if (requested_delay < loop_delay) {
 103             loop_delay = requested_delay;
 104             result = false;
 105         }
 106     }
 107
 108     if (timeService != NULL)
 109         timeService->tick();
 110
 111     for (dispatcher_vector::iterator i = dispatchers.begin();
 112             i != dispatchers.end(); ++i)
 113         if ((*i)->dispatch())
 114             result = false;
 115
 116     if (error) {
 117         ++errcount;
 118         debugs(1, 0, "Select loop Error. Retry " << errcount);
 119     } else
 120         errcount = 0;
 121
 122     if (errcount == 10)
 123         return true;
 124
 125     if (last_loop)
 126         return true;
 127
 128     return result;
 129 }
 130
 131 void
 132 EventLoop::setTimeService(TimeEngine *engine)
 133 {
 134     timeService = engine;
 135 }
 136
 137 void
 138 EventLoop::stop()
 139 {
 140     last_loop = true;
 141 }