texinfo/info/gc.c

   1 /* gc.c -- Functions to remember and garbage collect unused node contents. */
   2
   3 /* This file is part of GNU Info, a program for reading online documentation
   4    stored in Info format.
   5
   6    Copyright (C) 1993 Free Software Foundation, Inc.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2, or (at your option)
  11    any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  21
  22    Written by Brian Fox (bfox@ai.mit.edu). */
  23
  24 #include "info.h"
  25
  26 /* Array of pointers to the contents of gc-able nodes.  A pointer on this
  27    list can be garbage collected when no info window contains a node whose
  28    contents member match the pointer. */
  29 static char **gcable_pointers = (char **)NULL;
  30 static int gcable_pointers_index = 0;
  31 static int gcable_pointers_slots = 0;
  32
  33 /* Add POINTER to the list of garbage collectible pointers.  A pointer
  34    is not actually garbage collected until no info window contains a node
  35    whose contents member is equal to the pointer. */
  36 void
  37 add_gcable_pointer (pointer)
  38      char *pointer;
  39 {
  40   gc_pointers ();
  41   add_pointer_to_array (pointer, gcable_pointers_index, gcable_pointers,
  42                         gcable_pointers_slots, 10, char *);
  43 }
  44
  45 /* Grovel the list of info windows and gc-able pointers finding those
  46    node->contents which are collectible, and free them. */
  47 void
  48 gc_pointers ()
  49 {
  50   register int i, j, k;
  51   INFO_WINDOW *iw;
  52   char **new = (char **)NULL;
  53   int new_index = 0;
  54   int new_slots = 0;
  55
  56   if (!info_windows || !gcable_pointers_index)
  57     return;
  58
  59   for (i = 0; iw = info_windows[i]; i++)
  60     {
  61       for (j = 0; j < iw->nodes_index; j++)
  62         {
  63           NODE *node = iw->nodes[j];
  64
  65           /* If this node->contents appears in our list of gcable_pointers,
  66              it is not gc-able, so save it. */
  67           for (k = 0; k < gcable_pointers_index; k++)
  68             if (gcable_pointers[k] == node->contents)
  69               {
  70                 add_pointer_to_array
  71                   (node->contents, new_index, new, new_slots, 10, char *);
  72                 break;
  73               }
  74         }
  75     }
  76
  77   /* We have gathered all of the pointers which need to be saved.  Free any
  78      of the original pointers which do not appear in the new list. */
  79   for (i = 0; i < gcable_pointers_index; i++)
  80     {
  81       for (j = 0; j < new_index; j++)
  82         if (gcable_pointers[i] == new[j])
  83           break;
  84
  85       /* If we got all the way through the new list, then the old pointer
  86          can be garbage collected. */
  87       if (new && !new[j])
  88         free (gcable_pointers[i]);
  89     }
  90
  91   free (gcable_pointers);
  92   gcable_pointers = new;
  93   gcable_pointers_slots = new_slots;
  94   gcable_pointers_index = new_index;
  95 }