libbase/GC.cpp

   1 // GC.cpp: Garbage Collector, for Gnash
   2 //
   3 //   Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Free Software
   4 //   Foundation, Inc
   5 //
   6 // This program is free software; you can redistribute it and/or modify
   7 // it under the terms of the GNU General Public License as published by
   8 // the Free Software Foundation; either version 3 of the License, or
   9 // (at your option) any later version.
  10 //
  11 // This program is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15 //
  16 // You should have received a copy of the GNU General Public License
  17 // along with this program; if not, write to the Free Software
  18 // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19
  20 #include "GC.h"
  21
  22 #include <cstdlib>
  23
  24 #include "utility.h" // for typeName()
  25 #include "GnashAlgorithm.h"
  26
  27 #ifdef GNASH_GC_DEBUG
  28 # include "log.h"
  29 #endif
  30
  31
  32 namespace gnash {
  33
  34 GC::GC(GcRoot& root)
  35     :
  36     // might raise the default ...
  37     _maxNewCollectablesCount(64),
  38     _resListSize(0),
  39     _root(root),
  40     _lastResCount(0)
  41 #ifdef GNASH_GC_DEBUG
  42     , _collectorRuns(0)
  43 #endif
  44 {
  45 #ifdef GNASH_GC_DEBUG
  46     log_debug(_("GC %p created"), (void*)this);
  47 #endif
  48     char* gcgap = std::getenv("GNASH_GC_TRIGGER_THRESHOLD");
  49     if (gcgap) {
  50         const size_t gap = std::strtoul(gcgap, NULL, 0);
  51         _maxNewCollectablesCount = gap;
  52     }
  53 }
  54
  55 GC::~GC()
  56 {
  57 #ifdef GNASH_GC_DEBUG
  58     log_debug(_("GC deleted, deleting all managed resources - collector run %d times"), _collectorRuns);
  59 #endif
  60     for (ResList::const_iterator i = _resList.begin(), e = _resList.end();
  61             i != e; ++i) {
  62         delete *i;
  63     }
  64 }
  65
  66 size_t
  67 GC::cleanUnreachable()
  68 {
  69
  70 #if (GNASH_GC_DEBUG > 1)
  71     log_debug(_("GC: sweep scan started"));
  72 #endif
  73
  74     size_t deleted = 0;
  75
  76     for (ResList::iterator i = _resList.begin(), e = _resList.end(); i != e;) {
  77         const GcResource* res = *i;
  78         if (!res->isReachable()) {
  79
  80 #if GNASH_GC_DEBUG > 1
  81             log_debug(_("GC: recycling object %p (%s)"), res, typeName(*res));
  82 #endif
  83             ++deleted;
  84             delete res;
  85             i = _resList.erase(i); // _resListSize updated at end of loop
  86         }
  87         else {
  88             res->clearReachable();
  89             ++i;
  90         }
  91     }
  92
  93     _resListSize -= deleted;
  94
  95 #ifdef GNASH_GC_DEBUG
  96     log_debug(_("GC: recycled %d unreachable resources - %d left"),
  97             deleted, _resListSize);
  98 #endif
  99
 100     return deleted;
 101 }
 102
 103 void
 104 GC::runCycle()
 105 {
 106     //
 107     // Collection cycle
 108     //
 109
 110 #ifdef GNASH_GC_DEBUG
 111     ++_collectorRuns;
 112 #endif
 113
 114 #ifdef GNASH_GC_DEBUG
 115     log_debug(_("GC: collection cycle started - %d/%d new resources "
 116             "allocated since last run (from %d to %d)"),
 117             _resListSize - _lastResCount, _maxNewCollectablesCount,
 118             _lastResCount, _resListSize);
 119 #endif // GNASH_GC_DEBUG
 120
 121     // Mark all resources as reachable
 122     markReachable();
 123
 124     // clean unreachable resources, and mark the others as reachable again
 125     cleanUnreachable();
 126
 127     _lastResCount = _resListSize;
 128
 129 }
 130
 131 void
 132 GC::countCollectables(CollectablesCount& count) const
 133 {
 134     for (ResList::const_iterator i = _resList.begin(), e = _resList.end();
 135             i!=e; ++i) {
 136         ++count[typeName(**i)];
 137     }
 138 }
 139
 140 } // end of namespace gnash
 141
 142