src/EventLoop.cc

   1
   2 /*
   3  * $Id: EventLoop.cc,v 1.5 2007/07/23 19:55:21 rousskov 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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  14  *  development; see the SPONSORS file for full details.  Squid is
  15  *  Copyrighted (C) 2001 by the Regents of the University of
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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         primaryEngine(NULL)
  40 {}
  41
  42 void
  43 EventLoop::checkEngine(AsyncEngine * engine, bool const primary)
  44 {
  45     int requested_delay;
  46
  47     if (!primary)
  48         requested_delay = engine->checkEvents(0);
  49     else
  50         requested_delay = engine->checkEvents(loop_delay);
  51
  52     if (requested_delay < 0)
  53         switch (requested_delay) {
  54
  55         case AsyncEngine::EVENT_IDLE:
  56             debugs(1, 9, "Engine " << engine << " is idle.");
  57             break;
  58
  59         case AsyncEngine::EVENT_ERROR:
  60             runOnceResult = false;
  61             error = true;
  62             break;
  63
  64         default:
  65             fatal_dump("unknown AsyncEngine result");
  66         }
  67     else {
  68         /* not idle or error */
  69         runOnceResult = false;
  70
  71         if (requested_delay < loop_delay)
  72             loop_delay = requested_delay;
  73     }
  74 }
  75
  76 void
  77 EventLoop::prepareToRun()
  78 {
  79     last_loop = false;
  80     errcount = 0;
  81 }
  82
  83 void
  84 EventLoop::registerDispatcher(CompletionDispatcher *dispatcher)
  85 {
  86     dispatchers.push_back(dispatcher);
  87 }
  88
  89 void
  90 EventLoop::registerEngine(AsyncEngine *engine)
  91 {
  92     engines.push_back(engine);
  93 }
  94
  95 void
  96 EventLoop::run()
  97 {
  98     prepareToRun();
  99
 100     while (!runOnce())
 101
 102         ;
 103 }
 104
 105 bool
 106 EventLoop::runOnce()
 107 {
 108     runOnceResult = true;
 109     error = false;
 110     loop_delay = 10; /* 10 ms default delay */
 111
 112     for (engine_vector::iterator i = engines.begin();
 113             i != engines.end(); ++i) {
 114         /* check the primary outside the loop */
 115
 116         if (*i == primaryEngine)
 117             continue;
 118
 119         /* special case the last engine to be primary */
 120         checkEngine(*i, primaryEngine == NULL && (i - engines.end() == -1));
 121     }
 122
 123     if (primaryEngine != NULL)
 124         checkEngine(primaryEngine, true);
 125
 126     if (timeService != NULL)
 127         timeService->tick();
 128
 129     for (dispatcher_vector::iterator i = dispatchers.begin();
 130             i != dispatchers.end(); ++i)
 131         if ((*i)->dispatch())
 132             runOnceResult = false;
 133
 134     if (error) {
 135         ++errcount;
 136         debugs(1, 0, "Select loop Error. Retry " << errcount);
 137     } else
 138         errcount = 0;
 139
 140     if (errcount == 10)
 141         return true;
 142
 143     if (last_loop)
 144         return true;
 145
 146     return runOnceResult;
 147 }
 148
 149 void
 150 EventLoop::setPrimaryEngine(AsyncEngine * engine)
 151 {
 152     for (engine_vector::iterator i = engines.begin();
 153             i != engines.end(); ++i)
 154         if (*i == engine) {
 155             primaryEngine = engine;
 156             return;
 157         }
 158
 159     fatal("EventLoop::setPrimaryEngine: No such engine!.");
 160 }
 161
 162 void
 163 EventLoop::setTimeService(TimeEngine *engine)
 164 {
 165     timeService = engine;
 166 }
 167
 168 void
 169 EventLoop::stop()
 170 {
 171     last_loop = true;
 172 }