src/refresh.cc

   1
   2 /*
   3  * $Id: refresh.cc,v 1.1 1996/10/27 08:40:23 wessels Exp $
   4  *
   5  * DEBUG: section 22    Refresh Calculation
   6  * AUTHOR: Harvest Derived
   7  *
   8  * SQUID Internet Object Cache  http://www.nlanr.net/Squid/
   9  * --------------------------------------------------------
  10  *
  11  *  Squid is the result of efforts by numerous individuals from the
  12  *  Internet community.  Development is led by Duane Wessels of the
  13  *  National Laboratory for Applied Network Research and funded by
  14  *  the National Science Foundation.
  15  *
  16  *  This program is free software; you can redistribute it and/or modify
  17  *  it under the terms of the GNU General Public License as published by
  18  *  the Free Software Foundation; either version 2 of the License, or
  19  *  (at your option) any later version.
  20  *
  21  *  This program is distributed in the hope that it will be useful,
  22  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  23  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24  *  GNU General Public License for more details.
  25  *
  26  *  You should have received a copy of the GNU General Public License
  27  *  along with this program; if not, write to the Free Software
  28  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  29  *
  30  */
  31
  32 #ifndef USE_POSIX_REGEX
  33 #define USE_POSIX_REGEX         /* put before includes; always use POSIX */
  34 #endif
  35
  36 #include "squid.h"
  37
  38 /*
  39  * Defaults:
  40  *      MIN     NONE
  41  *      PCT     20%
  42  *      MAX     3 days
  43  */
  44 #define REFRESH_DEFAULT_MIN     0
  45 #define REFRESH_DEFAULT_PCT     20
  46 #define REFRESH_DEFAULT_MAX     259200
  47
  48 typedef struct _refresh_t {
  49     char *pattern;
  50     regex_t compiled_pattern;
  51     time_t min;
  52     int pct;
  53     time_t max;
  54     struct _refresh_t *next;
  55 } refresh_t;
  56
  57 static refresh_t *Refresh_tbl = NULL;
  58 static refresh_t *Refresh_tail = NULL;
  59
  60 static void
  61 refreshFreeList(refresh_t * t)
  62 {
  63     refresh_t *tnext;
  64
  65     for (; t; t = tnext) {
  66         tnext = t->next;
  67         safe_free(t->pattern);
  68         regfree(&t->compiled_pattern);
  69         safe_free(t);
  70     }
  71 }
  72
  73 void
  74 refreshFreeMemory(void)
  75 {
  76     refreshFreeList(Refresh_tbl);
  77     Refresh_tail = Refresh_tbl = NULL;
  78 }
  79
  80 void
  81 refreshAddToList(char *pattern, int opts, time_t min, int pct, time_t max)
  82 {
  83     refresh_t *t;
  84     regex_t comp;
  85     int flags = REG_EXTENDED;
  86     if (opts & REFRESH_ICASE)
  87         flags |= REG_ICASE;
  88     if (regcomp(&comp, pattern, flags) != REG_NOERROR) {
  89         debug(22, 0, "refreshAddToList: Invalid regular expression: %s\n",
  90             pattern);
  91         return;
  92     }
  93     pct = pct < 0 ? 0 : pct;
  94     max = max < 0 ? 0 : max;
  95     t = xcalloc(1, sizeof(refresh_t));
  96     t->pattern = (char *) xstrdup(pattern);
  97     t->compiled_pattern = comp;
  98     t->min = min;
  99     t->pct = pct;
 100     t->max = max;
 101     t->next = NULL;
 102     if (!Refresh_tbl)
 103         Refresh_tbl = t;
 104     if (Refresh_tail)
 105         Refresh_tail->next = t;
 106     Refresh_tail = t;
 107 }
 108
 109 /*
 110  * refreshCheck():
 111  *     return 1 if its time to revalidate this entry, 0 otherwise
 112  */
 113 int
 114 refreshCheck(StoreEntry * entry, request_t * request_unused)
 115 {
 116     refresh_t *R;
 117     time_t min = REFRESH_DEFAULT_MIN;
 118     int pct = REFRESH_DEFAULT_PCT;
 119     time_t max = REFRESH_DEFAULT_MAX;
 120     char *pattern = ".";
 121     time_t age;
 122     int factor;
 123     debug(22,1,"refreshCheck: '%s'\n", entry->url);
 124     for (R = Refresh_tbl; R; R = R->next) {
 125         if (regexec(&(R->compiled_pattern), entry->url, 0, 0, 0) != 0)
 126             continue;
 127         min = R->min;
 128         pct = R->pct;
 129         max = R->max;
 130         pattern = R->pattern;
 131         break;
 132     }
 133     debug(22, 1, "refreshCheck: Matched '%s %d %d%% %d'\n",
 134         pattern, (int) min, pct, (int) max);
 135     age = squid_curtime - entry->timestamp;
 136     debug(22,1,"refreshCheck: age = %d\n", (int) age);
 137     if (age <= min) {
 138         debug(22,1,"refreshCheck: NO: age < min\n");
 139         return 0;
 140     }
 141     if (-1 < entry->expires && entry->expires <= squid_curtime) {
 142         debug(22,1,"refreshCheck: YES: expires <= curtime\n");
 143         return 1;
 144     }
 145     if (age > max) {
 146         debug(22,1,"refreshCheck: YES: age > max\n");
 147         return 1;
 148     }
 149     if (entry->timestamp <= entry->lastmod) {
 150         debug(22,1,"refreshCheck: YES: lastvalid <= lastmod\n");
 151         return 1;
 152     }
 153     factor = 100 * age / (entry->timestamp - entry->lastmod);
 154     debug(22,1,"refreshCheck: factor = %d\n", factor);
 155     if (factor > pct) {
 156         debug(22,1,"refreshCheck: YES: factor > pc\n");
 157         return 1;
 158     }
 159     return 0;
 160 }