#!/usr/bin/perl
# TmNetWiki version 0.4 (September 11, 2002)
# Copyright (C) 2002 Adam Brate
#   <ab@adambrate.com> 
# Based on the GPLed UseModWiki 0.92
# Copyright (C) 2000-2001 Clifford A. Adams
#    <caadams@frontiernet.net> or <usemod@usemod.com>
# Based on the GPLed AtisWiki 0.3  (C) 1998 Markus Denker
#    <marcus@ira.uka.de>
# ...which was based on
#    the LGPLed CVWiki CVS-patches (C) 1997 Peter Merel
#    and The Original WikiWikiWeb  (C) Ward Cunningham
#        <ward@c2.com> (code reused with permission)
# Email and ThinLine options by Jim Mahoney <mahoney@marlboro.edu>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the
#    Free Software Foundation, Inc.
#    59 Temple Place, Suite 330
#    Boston, MA 02111-1307 USA


package Wiki::cache;
use strict;

# needs subs   Wiki::page: GetPageDirectory, CreatePageDir
#              Wiki::file: ReadFile, WriteStringToFile
#              Wiki::lock: RequestLockDir, ReleaseLockDir
# needs consts $UseCache, $HomePage, $ENV{QUERY_STRING}, $ENV{REQUEST_METHOD}, 
#              $LinkPattern, $FreeLinks, $FreeLinkPattern, $HtmlDir

use base 'Exporter';

use Wiki::consts;
use Wiki::page;
use Wiki::file;
use Wiki::lock;

#if ($^V and $^V gt v5.6.0) {
#    our @EXPORT;
#else {
   use vars qw(@EXPORT);
#}

@EXPORT=qw(
  DoCacheBrowse
  NewPageCacheClear
  UpdateHtmlCache
);

# local routines

sub UnlinkHtmlCache;
sub GetHtmlCacheFile;
sub RequestCacheLock;
sub ReleaseCacheLock;

# Simple HTML cache
sub DoCacheBrowse {
  my ($query, $idFile, $text, $success);

  return 0  if (!$UseCache);
  $query = $ENV{QUERY_STRING};
  if (($query eq "") && ($ENV{REQUEST_METHOD} eq "GET")) {
    $query = $HomePage;  # Allow caching of home page.
  }
  if (!($query =~ /^$LinkPattern$/)) {
    if (!($FreeLinks && ($query =~ /^$FreeLinkPattern$/))) {
      return 0;  # Only use cache for simple links
    }
  }
  $idFile = &GetHtmlCacheFile($query);
  if (-f $idFile) {
    ($success, $text) = ReadFile($idFile);
    print $text if $success;
    return $success;
  }
  return 0;
}

sub UpdateHtmlCache {
  my ($id, $html) = @_;
  my $idFile;

  $idFile = &GetHtmlCacheFile($id);
  &CreatePageDir($HtmlDir, $id);
  if (&RequestCacheLock()) {
    &WriteStringToFile($idFile, $html);
    &ReleaseCacheLock();
  }
}

sub UnlinkHtmlCache {
  my ($id) = @_;
  my $idFile;

  $idFile = &GetHtmlCacheFile($id);
  if (-f $idFile) {
    unlink($idFile);
  }
}

sub NewPageCacheClear {
  my ($id) = @_;
  my $name;

  return if (!$UseCache);
  $id =~ s|.+/|/|;  # If subpage, search for just the subpage
  # The following code used to search the body for the $id
  foreach $name (&AllPagesList()) {  # Remove all to be safe
    &UnlinkHtmlCache($name);
  }
}

sub GetHtmlCacheFile {
  my ($id) = @_;

  return $HtmlDir . "/" . &GetPageDirectory($id) . "/$id.htm";
}

sub RequestCacheLock {
  # 4 tries, 2 second wait, do not die on error
  return &RequestLockDir('cache', 4, 2, 0);
}

sub ReleaseCacheLock {
  &ReleaseLockDir('cache');
}

1;