path: root/IkiWiki.pm

#!/usr/bin/perl

package IkiWiki;
use warnings;
use strict;
use Encode;
use HTML::Entities;
use URI::Escape q{uri_escape_utf8};
use POSIX;
use open qw{:utf8 :std};

use vars qw{%config %links %oldlinks %pagemtime %pagectime %pagecase
            %renderedfiles %oldrenderedfiles %pagesources %destsources
        %depends %hooks %forcerebuild $gettext_obj};

use Exporter q{import};
our @EXPORT = qw(hook debug error template htmlpage add_depends pagespec_match
                 bestlink htmllink readfile writefile pagetype srcfile pagename
                 displaytime will_render gettext urlto targetpage
                 %config %links %renderedfiles %pagesources %destsources);
our $VERSION = 2.00; # plugin interface version, next is ikiwiki version
our $version='unknown'; # VERSION_AUTOREPLACE done by Makefile, DNE
my $installdir=''; # INSTALLDIR_AUTOREPLACE done by Makefile, DNE

# Optimisation.
use Memoize;
memoize("abs2rel");
memoize("pagespec_translate");
memoize("file_pruned");

sub defaultconfig () { #{{{
    wiki_file_prune_regexps => [qr/\.\./, qr/^\./, qr/\/\./,
        qr/\.x?html?$/, qr/\.ikiwiki-new$/,
        qr/(^|\/).svn\//, qr/.arch-ids\//, qr/{arch}\//,
        qr/\.dpkg-tmp$/],
    wiki_link_regexp => qr{
        \[\[            # beginning of link
        (?:
            ([^\]\|]+)  # 1: link text
            \|      # followed by '|'
        )?          # optional

        ([^\s\]#]+)     # 2: page to link to
        (?:
            \#      # '#', beginning of anchor
            ([^\s\]]+)  # 3: anchor text
        )?          # optional

        \]\]            # end of link
    }x,
    wiki_file_regexp => qr/(^[-[:alnum:]_.:\/+]+$)/,
    web_commit_regexp => qr/^web commit (by (.*?(?=: |$))|from (\d+\.\d+\.\d+\.\d+)):?(.*)/,
    verbose => 0,
    syslog => 0,
    wikiname => "wiki",
    default_pageext => "mdwn",
    htmlext => "html",
    cgi => 0,
    post_commit => 0,
    rcs => '',
    notify => 0,
    url => '',
    cgiurl => '',
    historyurl => '',
    diffurl => '',
    rss => 0,
    atom => 0,
    discussion => 1,
    rebuild => 0,
    refresh => 0,
    getctime => 0,
    w3mmode => 0,
    wrapper => undef,
    wrappermode => undef,
    svnrepo => undef,
    svnpath => "trunk",
    gitorigin_branch => "origin",
    gitmaster_branch => "master",
    srcdir => undef,
    destdir => undef,
    pingurl => [],
    templatedir => "$installdir/share/ikiwiki/templates",
    underlaydir => "$installdir/share/ikiwiki/basewiki",
    setup => undef,
    adminuser => undef,
    adminemail => undef,
    plugin => [qw{mdwn inline htmlscrubber passwordauth openid signinedit
                  lockedit conditional}],
    libdir => undef,
    timeformat => '%c',
    locale => undef,
    sslcookie => 0,
    httpauth => 0,
    userdir => "",
    usedirs => 1,
    numbacklinks => 10,
    account_creation_password => "",
} #}}}
   
sub checkconfig () { #{{{
    # locale stuff; avoid LC_ALL since it overrides everything
    if (defined $ENV{LC_ALL}) {
        $ENV{LANG} = $ENV{LC_ALL};
        delete $ENV{LC_ALL};
    }
    if (defined $config{locale}) {
        if (POSIX::setlocale(&POSIX::LC_ALL, $config{locale})) {
            $ENV{LANG}=$config{locale};
            $gettext_obj=undef;
        }
    }

    if ($config{w3mmode}) {
        eval q{use Cwd q{abs_path}};
        error($@) if $@;
        $config{srcdir}=possibly_foolish_untaint(abs_path($config{srcdir}));
        $config{destdir}=possibly_foolish_untaint(abs_path($config{destdir}));
        $config{cgiurl}="file:///\$LIB/ikiwiki-w3m.cgi/".$config{cgiurl}
            unless $config{cgiurl} =~ m!file:///!;
        $config{url}="file://".$config{destdir};
    }

    if ($config{cgi} && ! length $config{url}) {
        error(gettext("Must specify url to wiki with --url when using --cgi"));
    }
    
    $config{wikistatedir}="$config{srcdir}/.ikiwiki"
        unless exists $config{wikistatedir};
    
    if ($config{rcs}) {
        eval qq{use IkiWiki::Rcs::$config{rcs}};
        if ($@) {
            error("Failed to load RCS module IkiWiki::Rcs::$config{rcs}: $@");
        }
    }
    else {
        require IkiWiki::Rcs::Stub;
    }

    run_hooks(checkconfig => sub { shift->() });
} #}}}

sub loadplugins () { #{{{
    if (defined $config{libdir}) {
        unshift @INC, $config{libdir};
    }

    loadplugin($_) foreach @{$config{plugin}};

    run_hooks(getopt => sub { shift->() });
    if (grep /^-/, @ARGV) {
        print STDERR "Unknown option: $_\n"
            foreach grep /^-/, @ARGV;
        usage();
    }
} #}}}

sub loadplugin ($) { #{{{
    my $plugin=shift;

    return if grep { $_ eq $plugin} @{$config{disable_plugins}};

    foreach my $dir ($config{libdir}, "$installdir/lib/ikiwiki") {
        if (defined $dir && -x "$dir/plugins/$plugin") {
            require IkiWiki::Plugin::external;
            import IkiWiki::Plugin::external "$dir/plugins/$plugin";
            return 1;
        }
    }

    my $mod="IkiWiki::Plugin::".possibly_foolish_untaint($plugin);
    eval qq{use $mod};
    if ($@) {
        error("Failed to load plugin $mod: $@");
    }
    return 1;
} #}}}

sub error ($;$) { #{{{
    my $message=shift;
    my $cleaner=shift;
    if ($config{cgi}) {
        print "Content-type: text/html\n\n";
        print misctemplate(gettext("Error"),
            "<p>".gettext("Error").": $message</p>");
    }
    log_message('err' => $message) if $config{syslog};
    if (defined $cleaner) {
        $cleaner->();
    }
    die $message."\n";
} #}}}

sub debug ($) { #{{{
    return unless $config{verbose};
    log_message(debug => @_);
} #}}}

my $log_open=0;
sub log_message ($$) { #{{{
    my $type=shift;

    if ($config{syslog}) {
        require Sys::Syslog;
        unless ($log_open) {
            Sys::Syslog::setlogsock('unix');
            Sys::Syslog::openlog('ikiwiki', '', 'user');
            $log_open=1;
        }
        eval {
            Sys::Syslog::syslog($type, "[$config{wikiname}] %s", join(" ", @_));
        };
    }
    elsif (! $config{cgi}) {
        print "@_\n";
    }
    else {
        print STDERR "@_\n";
    }
} #}}}

sub possibly_foolish_untaint ($) { #{{{
    my $tainted=shift;
    my ($untainted)=$tainted=~/(.*)/s;
    return $untainted;
} #}}}

sub basename ($) { #{{{
    my $file=shift;

    $file=~s!.*/+!!;
    return $file;
} #}}}

sub dirname ($) { #{{{
    my $file=shift;

    $file=~s!/*[^/]+$!!;
    return $file;
} #}}}

sub pagetype ($) { #{{{
    my $page=shift;
    
    if ($page =~ /\.([^.]+)$/) {
        return $1 if exists $hooks{htmlize}{$1};
    }
    return undef;
} #}}}

sub pagename ($) { #{{{
    my $file=shift;

    my $type=pagetype($file);
    my $page=$file;
    $page=~s/\Q.$type\E*$// if defined $type;
    return $page;
} #}}}

sub targetpage ($$) { #{{{
    my $page=shift;
    my $ext=shift;
    
    if (! $config{usedirs} || $page =~ /^index$/ ) {
        return $page.".".$ext;
    } else {
        return $page."/index.".$ext;
    }
} #}}}

sub htmlpage ($) { #{{{
    my $page=shift;
    
    return targetpage($page, $config{htmlext});
} #}}}

sub srcfile ($) { #{{{
    my $file=shift;

    return "$config{srcdir}/$file" if -e "$config{srcdir}/$file";
    return "$config{underlaydir}/$file" if -e "$config{underlaydir}/$file";
    error("internal error: $file cannot be found in $config{srcdir} or $config{underlaydir}");
} #}}}

sub readfile ($;$$) { #{{{
    my $file=shift;
    my $binary=shift;
    my $wantfd=shift;

    if (-l $file) {
        error("cannot read a symlink ($file)");
    }
    
    local $/=undef;
    open (IN, $file) || error("failed to read $file: $!");
    binmode(IN) if ($binary);
    return \*IN if $wantfd;
    my $ret=<IN>;
    close IN || error("failed to read $file: $!");
    return $ret;
} #}}}

sub writefile ($$$;$$) { #{{{
    my $file=shift; # can include subdirs
    my $destdir=shift; # directory to put file in
    my $content=shift;
    my $binary=shift;
    my $writer=shift;
    
    my $test=$file;
    while (length $test) {
        if (-l "$destdir/$test") {
            error("cannot write to a symlink ($test)");
        }
        $test=dirname($test);
    }
    my $newfile="$destdir/$file.ikiwiki-new";
    if (-l $newfile) {
        error("cannot write to a symlink ($newfile)");
    }

    my $dir=dirname($newfile);
    if (! -d $dir) {
        my $d="";
        foreach my $s (split(m!/+!, $dir)) {
            $d.="$s/";
            if (! -d $d) {
                mkdir($d) || error("failed to create directory $d: $!");
            }
        }
    }

    my $cleanup = sub { unlink($newfile) };
    open (OUT, ">$newfile") || error("failed to write $newfile: $!", $cleanup);
    binmode(OUT) if ($binary);
    if ($writer) {
        $writer->(\*OUT, $cleanup);
    }
    else {
        print OUT $content or error("failed writing to $newfile: $!", $cleanup);
    }
    close OUT || error("failed saving $newfile: $!", $cleanup);
    rename($newfile, "$destdir/$file") || 
        error("failed renaming $newfile to $destdir/$file: $!", $cleanup);
} #}}}

my %cleared;
sub will_render ($$;$) { #{{{
    my $page=shift;
    my $dest=shift;
    my $clear=shift;

    # Important security check.
    if (-e "$config{destdir}/$dest" && ! $config{rebuild} &&
        ! grep { $_ eq $dest } (@{$renderedfiles{$page}}, @{$oldrenderedfiles{$page}})) {
        error("$config{destdir}/$dest independently created, not overwriting with version from $page");
    }

    if (! $clear || $cleared{$page}) {
        $renderedfiles{$page}=[$dest, grep { $_ ne $dest } @{$renderedfiles{$page}}];
    }
    else {
        foreach my $old (@{$renderedfiles{$page}}) {
            delete $destsources{$old};
        }
        $renderedfiles{$page}=[$dest];
        $cleared{$page}=1;
    }
    $destsources{$dest}=$page;
} #}}}

sub bestlink ($$) { #{{{
    my $page=shift;
    my $link=shift;
    
    my $cwd=$page;
    if ($link=~s/^\/+//) {
        # absolute links
        $cwd="";
    }

    do {
        my $l=$cwd;
        $l.="/" if length $l;
        $l.=$link;

        if (exists $links{$l}) {
            return $l;
        }
        elsif (exists $pagecase{lc $l}) {
            return $pagecase{lc $l};
        }
    } while $cwd=~s!/?[^/]+$!!;

    if (length $config{userdir}) {
        my $l = "$config{userdir}/".lc($link);
        if (exists $links{$l}) {
            return $l;
        }
        elsif (exists $pagecase{lc $l}) {
            return $pagecase{lc $l};
        }
    }

    #print STDERR "warning: page $page, broken link: $link\n";
    return "";
} #}}}

sub isinlinableimage ($) { #{{{
    my $file=shift;
    
    $file=~/\.(png|gif|jpg|jpeg)$/i;
} #}}}

sub pagetitle ($;$) { #{{{
    my $page=shift;
    my $unescaped=shift;

    if ($unescaped) {
        $page=~s/(__(\d+)__|_)/$1 eq '_' ? ' ' : chr($2)/eg;
    }
    else {
        $page=~s/(__(\d+)__|_)/$1 eq '_' ? ' ' : "&#$2;"/eg;
    }

    return $page;
} #}}}

sub titlepage ($) { #{{{
    my $title=shift;
    $title=~s/([^-[:alnum:]:+\/.])/$1 eq ' ' ? '_' : "__".ord($1)."__"/eg;
    return $title;
} #}}}

sub linkpage ($) { #{{{
    my $link=shift;
    $link=~s/([^-[:alnum:]:+\/._])/$1 eq ' ' ? '_' : "__".ord($1)."__"/eg;
    return $link;
} #}}}

sub cgiurl (@) { #{{{
    my %params=@_;

    return $config{cgiurl}."?".
        join("&amp;", map $_."=".uri_escape_utf8($params{$_}), keys %params);
} #}}}

sub baseurl (;$) { #{{{
    my $page=shift;

    return "$config{url}/" if ! defined $page;
    
    $page=htmlpage($page);
    $page=~s/[^\/]+$//;
    $page=~s/[^\/]+\//..\//g;
    return $page;
} #}}}

sub abs2rel ($$) { #{{{
    # Work around very innefficient behavior in File::Spec if abs2rel
    # is passed two relative paths. It's much faster if paths are
    # absolute! (Debian bug #376658; fixed in debian unstable now)
    my $path="/".shift;
    my $base="/".shift;

    require File::Spec;
    my $ret=File::Spec->abs2rel($path, $base);
    $ret=~s/^// if defined $ret;
    return $ret;
} #}}}

sub displaytime ($) { #{{{
    my $time=shift;

    # strftime doesn't know about encodings, so make sure
    # its output is properly treated as utf8
    return decode_utf8(POSIX::strftime(
            $config{timeformat}, localtime($time)));
} #}}}

sub beautify_url ($) { #{{{
    my $url=shift;

    $url =~ s!/index.$config{htmlext}$!/!;
    $url =~ s!^$!./!; # Browsers don't like empty links...

    return $url;
} #}}}

sub urlto ($$) { #{{{
    my $to=shift;
    my $from=shift;

    if (! length $to) {
        return beautify_url(baseurl($from));
    }

    if (! $destsources{$to}) {
        $to=htmlpage($to);
    }

    my $link = abs2rel($to, dirname(htmlpage($from)));

    return beautify_url($link);
} #}}}

sub htmllink ($$$;@) { #{{{
    my $lpage=shift; # the page doing the linking
    my $page=shift; # the page that will contain the link (different for inline)
    my $link=shift;
    my %opts=@_;

    my $bestlink;
    if (! $opts{forcesubpage}) {
        $bestlink=bestlink($lpage, $link);
    }
    else {
        $bestlink="$lpage/".lc($link);
    }

    my $linktext;
    if (defined $opts{linktext}) {
        $linktext=$opts{linktext};
    }
    else {
        $linktext=pagetitle(basename($link));
    }
    
    return "<span class=\"selflink\">$linktext</span>"
        if length $bestlink && $page eq $bestlink;
    
    if (! $destsources{$bestlink}) {
        $bestlink=htmlpage($bestlink);

        if (! $destsources{$bestlink}) {
            return $linktext unless length $config{cgiurl};
            return "<span><a href=\"".
                cgiurl(
                    do => "create",
                    page => pagetitle(lc($link), 1),
                    from => $lpage
                ).
                "\">?</a>$linktext</span>"
        }
    }
    
    $bestlink=abs2rel($bestlink, dirname(htmlpage($page)));
    $bestlink=beautify_url($bestlink);
    
    if (! $opts{noimageinline} && isinlinableimage($bestlink)) {
        return "<img src=\"$bestlink\" alt=\"$linktext\" />";
    }

    if (defined $opts{anchor}) {
        $bestlink.="#".$opts{anchor};
    }

    my @attrs;
    if (defined $opts{rel}) {
        push @attrs, ' rel="'.$opts{rel}.'"';
    }

    return "<a href=\"$bestlink\"@attrs>$linktext</a>";
} #}}}

sub htmlize ($$$) { #{{{
    my $page=shift;
    my $type=shift;
    my $content=shift;

    if (exists $hooks{htmlize}{$type}) {
        $content=$hooks{htmlize}{$type}{call}->(
            page => $page,
            content => $content,
        );
    }
    else {
        error("htmlization of $type not supported");
    }

    run_hooks(sanitize => sub {
        $content=shift->(
            page => $page,
            content => $content,
        );
    });

    return $content;
} #}}}

sub linkify ($$$) { #{{{
    my $lpage=shift; # the page containing the links
    my $page=shift; # the page the link will end up on (different for inline)
    my $content=shift;

    $content =~ s{(\\?)$config{wiki_link_regexp}}{
        defined $2
            ? ( $1 
                ? "[[$2|$3".($4 ? "#$4" : "")."]]" 
                : htmllink($lpage, $page, linkpage($3),
                    anchor => $4, linktext => pagetitle($2)))
            : ( $1 
                ? "[[$3".($4 ? "#$4" : "")."]]"
                : htmllink($lpage, $page, linkpage($3),
                    anchor => $4))
    }eg;
    
    return $content;
} #}}}

my %preprocessing;
our $preprocess_preview=0;
sub preprocess ($$$;$$) { #{{{
    my $page=shift; # the page the data comes from
    my $destpage=shift; # the page the data will appear in (different for inline)
    my $content=shift;
    my $scan=shift;
    my $preview=shift;

    # Using local because it needs to be set within any nested calls
    # of this function.
    local $preprocess_preview=$preview if defined $preview;

    my $handle=sub {
        my $escape=shift;
        my $command=shift;
        my $params=shift;
        if (length $escape) {
            return "\\[[$command $params]]";
        }
        elsif (exists $hooks{preprocess}{$command}) {
            return "" if $scan && ! $hooks{preprocess}{$command}{scan};
            # Note: preserve order of params, some plugins may
            # consider it significant.
            my @params;
            while ($params =~ m{
                (?:(\w+)=)?     # 1: named parameter key?
                (?:
                    """(.*?)""" # 2: triple-quoted value
                |
                    "([^"]+)"   # 3: single-quoted value
                |
                    (\S+)       # 4: unquoted value
                )
                (?:\s+|$)       # delimiter to next param
            }sgx) {
                my $key=$1;
                my $val;
                if (defined $2) {
                    $val=$2;
                    $val=~s/\r\n/\n/mg;
                    $val=~s/^\n+//g;
                    $val=~s/\n+$//g;
                }
                elsif (defined $3) {
                    $val=$3;
                }
                elsif (defined $4) {
                    $val=$4;
                }

                if (defined $key) {
                    push @params, $key, $val;
                }
                else {
                    push @params, $val, '';
                }
            }
            if ($preprocessing{$page}++ > 3) {
                # Avoid loops of preprocessed pages preprocessing
                # other pages that preprocess them, etc.
                #translators: The first parameter is a
                #translators: preprocessor directive name,
                #translators: the second a page name, the
                #translators: third a number.
                return "[[".sprintf(gettext("%s preprocessing loop detected on %s at depth %i"),
                    $command, $page, $preprocessing{$page}).
                "]]";
            }
            my $ret=$hooks{preprocess}{$command}{call}->(
                @params,
                page => $page,
                destpage => $destpage,
                preview => $preprocess_preview,
            );
            $preprocessing{$page}--;
            return $ret;
        }
        else {
            return "\\[[$command $params]]";
        }
    };
    
    $content =~ s{
        (\\?)       # 1: escape?
        \[\[        # directive open
        (\w+)       # 2: command
        \s+
        (       # 3: the parameters..
            (?:
                (?:\w+=)?       # named parameter key?
                (?:
                    """.*?"""   # triple-quoted value
                    |
                    "[^"]+"     # single-quoted value
                    |
                    [^\s\]]+    # unquoted value
                )
                \s*         # whitespace or end
                            # of directive
            )
        *)      # 0 or more parameters
        \]\]        # directive closed
    }{$handle->($1, $2, $3)}sexg;
    return $content;
} #}}}

sub filter ($$$) { #{{{
    my $page=shift;
    my $destpage=shift;
    my $content=shift;

    run_hooks(filter => sub {
        $content=shift->(page => $page, destpage => $destpage, 
            content => $content);
    });

    return $content;
} #}}}

sub indexlink () { #{{{
    return "<a href=\"$config{url}\">$config{wikiname}</a>";
} #}}}

sub lockwiki (;$) { #{{{
    my $wait=@_ ? shift : 1;
    # Take an exclusive lock on the wiki to prevent multiple concurrent
    # run issues. The lock will be dropped on program exit.
    if (! -d $config{wikistatedir}) {
        mkdir($config{wikistatedir});
    }
    open(WIKILOCK, ">$config{wikistatedir}/lockfile") ||
        error ("cannot write to $config{wikistatedir}/lockfile: $!");
    if (! flock(WIKILOCK, 2 | 4)) { # LOCK_EX | LOCK_NB
        if ($wait) {
            debug("wiki seems to be locked, waiting for lock");
            my $wait=600; # arbitrary, but don't hang forever to 
                          # prevent process pileup
            for (1..$wait) {
                return if flock(WIKILOCK, 2 | 4);
                sleep 1;
            }
            error("wiki is locked; waited $wait seconds without lock being freed (possible stuck process or stale lock?)");
        }
        else {
            return 0;
        }
    }
    return 1;
} #}}}

sub unlockwiki () { #{{{
    close WIKILOCK;
} #}}}

sub commit_hook_enabled () { #{{{
    open(COMMITLOCK, "+>$config{wikistatedir}/commitlock") ||
        error ("cannot write to $config{wikistatedir}/commitlock: $!");
    if (! flock(COMMITLOCK, 1 | 4)) { # LOCK_SH | LOCK_NB to test
        close COMMITLOCK;
        return 0;
    }
    close COMMITLOCK;
    return 1;
} #}}}

sub disable_commit_hook () { #{{{
    open(COMMITLOCK, ">$config{wikistatedir}/commitlock") ||
        error ("cannot write to $config{wikistatedir}/commitlock: $!");
    if (! flock(COMMITLOCK, 2)) { # LOCK_EX
        error("failed to get commit lock");
    }
} #}}}

sub enable_commit_hook () { #{{{
    close COMMITLOCK;
} #}}}

sub loadindex () { #{{{
    open (IN, "$config{wikistatedir}/index") || return;
    while (<IN>) {
        $_=possibly_foolish_untaint($_);
        chomp;
        my %items;
        $items{link}=[];
        $items{dest}=[];
        foreach my $i (split(/ /, $_)) {
            my ($item, $val)=split(/=/, $i, 2);
            push @{$items{$item}}, decode_entities($val);
        }

        next unless exists $items{src}; # skip bad lines for now

        my $page=pagename($items{src}[0]);
        if (! $config{rebuild}) {
            $pagesources{$page}=$items{src}[0];
            $pagemtime{$page}=$items{mtime}[0];
            $oldlinks{$page}=[@{$items{link}}];
            $links{$page}=[@{$items{link}}];
            $depends{$page}=$items{depends}[0] if exists $items{depends};
            $destsources{$_}=$page foreach @{$items{dest}};
            $renderedfiles{$page}=[@{$items{dest}}];
            $pagecase{lc $page}=$page;
        }
        $oldrenderedfiles{$page}=[@{$items{dest}}];
        $pagectime{$page}=$items{ctime}[0];
    }
    close IN;
} #}}}

sub saveindex () { #{{{
    run_hooks(savestate => sub { shift->() });

    if (! -d $config{wikistatedir}) {
        mkdir($config{wikistatedir});
    }
    my $newfile="$config{wikistatedir}/index.new";
    my $cleanup = sub { unlink($newfile) };
    open (OUT, ">$newfile") || error("cannot write to $newfile: $!", $cleanup);
    foreach my $page (keys %pagemtime) {
        next unless $pagemtime{$page};
        my $line="mtime=$pagemtime{$page} ".
            "ctime=$pagectime{$page} ".
            "src=$pagesources{$page}";
        $line.=" dest=$_" foreach @{$renderedfiles{$page}};
        my %count;
        $line.=" link=$_" foreach grep { ++$count{$_} == 1 } @{$links{$page}};
        if (exists $depends{$page}) {
            $line.=" depends=".encode_entities($depends{$page}, " \t\n");
        }
        print OUT $line."\n" || error("failed writing to $newfile: $!", $cleanup);
    }
    close OUT || error("failed saving to $newfile: $!", $cleanup);
    rename($newfile, "$config{wikistatedir}/index") ||
        error("failed renaming $newfile to $config{wikistatedir}/index", $cleanup);
} #}}}

sub template_file ($) { #{{{
    my $template=shift;

    foreach my $dir ($config{templatedir}, "$installdir/share/ikiwiki/templates") {
        return "$dir/$template" if -e "$dir/$template";
    }
    return undef;
} #}}}

sub template_params (@) { #{{{
    my $filename=template_file(shift);

    if (! defined $filename) {
        return if wantarray;
        return "";
    }

    my @ret=(
        filter => sub {
            my $text_ref = shift;
            $$text_ref=&Encode::decode_utf8($$text_ref);
        },
        filename => $filename,
        loop_context_vars => 1,
        die_on_bad_params => 0,
        @_
    );
    return wantarray ? @ret : {@ret};
} #}}}

sub template ($;@) { #{{{
    require HTML::Template;
    HTML::Template->new(template_params(@_));
} #}}}

sub misctemplate ($$;@) { #{{{
    my $title=shift;
    my $pagebody=shift;
    
    my $template=template("misc.tmpl");
    $template->param(
        title => $title,
        indexlink => indexlink(),
        wikiname => $config{wikiname},
        pagebody => $pagebody,
        baseurl => baseurl(),
        @_,
    );
    run_hooks(pagetemplate => sub {
        shift->(page => "", destpage => "", template => $template);
    });
    return $template->output;
}#}}}

sub hook (@) { # {{{
    my %param=@_;
    
    if (! exists $param{type} || ! ref $param{call} || ! exists $param{id}) {
        error "hook requires type, call, and id parameters";
    }

    return if $param{no_override} && exists $hooks{$param{type}}{$param{id}};
    
    $hooks{$param{type}}{$param{id}}=\%param;
} # }}}

sub run_hooks ($$) { # {{{
    # Calls the given sub for each hook of the given type,
    # passing it the hook function to call.
    my $type=shift;
    my $sub=shift;

    if (exists $hooks{$type}) {
        my @deferred;
        foreach my $id (keys %{$hooks{$type}}) {
            if ($hooks{$type}{$id}{last}) {
                push @deferred, $id;
                next;
            }
            $sub->($hooks{$type}{$id}{call});
        }
        foreach my $id (@deferred) {
            $sub->($hooks{$type}{$id}{call});
        }
    }
} #}}}

sub globlist_to_pagespec ($) { #{{{
    my @globlist=split(' ', shift);

    my (@spec, @skip);
    foreach my $glob (@globlist) {
        if ($glob=~/^!(.*)/) {
            push @skip, $glob;
        }
        else {
            push @spec, $glob;
        }
    }

    my $spec=join(" or ", @spec);
    if (@skip) {
        my $skip=join(" and ", @skip);
        if (length $spec) {
            $spec="$skip and ($spec)";
        }
        else {
            $spec=$skip;
        }
    }
    return $spec;
} #}}}

sub is_globlist ($) { #{{{
    my $s=shift;
    $s=~/[^\s]+\s+([^\s]+)/ && $1 ne "and" && $1 ne "or";
} #}}}

sub safequote ($) { #{{{
    my $s=shift;
    $s=~s/[{}]//g;
    return "q{$s}";
} #}}}

sub add_depends ($$) { #{{{
    my $page=shift;
    my $pagespec=shift;
    
    if (! exists $depends{$page}) {
        $depends{$page}=$pagespec;
    }
    else {
        $depends{$page}=pagespec_merge($depends{$page}, $pagespec);
    }
} # }}}

sub file_pruned ($$) { #{{{
    require File::Spec;
    my $file=File::Spec->canonpath(shift);
    my $base=File::Spec->canonpath(shift);
    $file=~s#^\Q$base\E/*##;

    my $regexp='('.join('|', @{$config{wiki_file_prune_regexps}}).')';
    $file =~ m/$regexp/;
} #}}}

sub gettext { #{{{
    # Only use gettext in the rare cases it's needed.
    if (exists $ENV{LANG} || exists $ENV{LC_ALL} || exists $ENV{LC_MESSAGES}) {
        if (! $gettext_obj) {
            $gettext_obj=eval q{
                use Locale::gettext q{textdomain};
                Locale::gettext->domain('ikiwiki')
            };
            if ($@) {
                print STDERR "$@";
                $gettext_obj=undef;
                return shift;
            }
        }
        return $gettext_obj->get(shift);
    }
    else {
        return shift;
    }
} #}}}

sub pagespec_merge ($$) { #{{{
    my $a=shift;
    my $b=shift;

    return $a if $a eq $b;

        # Support for old-style GlobLists.
        if (is_globlist($a)) {
                $a=globlist_to_pagespec($a);
        }
        if (is_globlist($b)) {
                $b=globlist_to_pagespec($b);
        }

    return "($a) or ($b)";
} #}}}

sub pagespec_translate ($) { #{{{
    # This assumes that $page is in scope in the function
    # that evalulates the translated pagespec code.
    my $spec=shift;

    # Support for old-style GlobLists.
    if (is_globlist($spec)) {
        $spec=globlist_to_pagespec($spec);
    }

    # Convert spec to perl code.
    my $code="";
    while ($spec=~m{
        \s*     # ignore whitespace
        (       # 1: match a single word
            \!      # !
        |
            \(      # (
        |
            \)      # )
        |
            \w+\([^\)]*\)   # command(params)
        |
            [^\s()]+    # any other text
        )
        \s*     # ignore whitespace
    }igx) {
        my $word=$1;
        if (lc $word eq "and") {
            $code.=" &&";
        }
        elsif (lc $word eq "or") {
            $code.=" ||";
        }
        elsif ($word eq "(" || $word eq ")" || $word eq "!") {
            $code.=" ".$word;
        }
        elsif ($word =~ /^(\w+)\((.*)\)$/) {
            if (exists $IkiWiki::PageSpec::{"match_$1"}) {
                $code.="IkiWiki::PageSpec::match_$1(\$page, ".safequote($2).", \@params)";
            }
            else {
                $code.=" 0";
            }
        }
        else {
            $code.=" IkiWiki::PageSpec::match_glob(\$page, ".safequote($word).", \@params)";
        }
    }

    return $code;
} #}}}

sub pagespec_match ($$;@) { #{{{
    my $page=shift;
    my $spec=shift;
    my @params=@_;

    # Backwards compatability with old calling convention.
    if (@params == 1) {
        unshift @params, "location";
    }

    my $ret=eval pagespec_translate($spec);
    return IkiWiki::FailReason->new("syntax error") if $@;
    return $ret;
} #}}}

package IkiWiki::FailReason;

use overload ( #{{{
    '""'    => sub { ${$_[0]} },
    '0+'    => sub { 0 },
    '!' => sub { bless $_[0], 'IkiWiki::SuccessReason'},
    fallback => 1,
); #}}}

sub new { #{{{
    bless \$_[1], $_[0];
} #}}}

package IkiWiki::SuccessReason;

use overload ( #{{{
    '""'    => sub { ${$_[0]} },
    '0+'    => sub { 1 },
    '!' => sub { bless $_[0], 'IkiWiki::FailReason'},
    fallback => 1,
); #}}}

sub new { #{{{
    bless \$_[1], $_[0];
}; #}}}

package IkiWiki::PageSpec;

sub match_glob ($$;@) { #{{{
    my $page=shift;
    my $glob=shift;
    my %params=@_;
    
    my $from=exists $params{location} ? $params{location} : "";
    
    # relative matching
    if ($glob =~ m!^\./!) {
        $from=~s#/?[^/]+$##;
        $glob=~s#^\./##;
        $glob="$from/$glob" if length $from;
    }

    # turn glob into safe regexp
    $glob=quotemeta($glob);
    $glob=~s/\\\*/.*/g;
    $glob=~s/\\\?/./g;

    if ($page=~/^$glob$/i) {
        return IkiWiki::SuccessReason->new("$glob matches $page");
    }
    else {
        return IkiWiki::FailReason->new("$glob does not match $page");
    }
} #}}}

sub match_link ($$;@) { #{{{
    my $page=shift;
    my $link=lc(shift);
    my %params=@_;

    my $from=exists $params{location} ? $params{location} : "";

    # relative matching
    if ($link =~ m!^\.! && defined $from) {
        $from=~s#/?[^/]+$##;
        $link=~s#^\./##;
        $link="$from/$link" if length $from;
    }

    my $links = $IkiWiki::links{$page} or return undef;
    return IkiWiki::FailReason->new("$page has no links") unless @$links;
    my $bestlink = IkiWiki::bestlink($from, $link);
    foreach my $p (@$links) {
        if (length $bestlink) {
            return IkiWiki::SuccessReason->new("$page links to $link")
                if $bestlink eq IkiWiki::bestlink($page, $p);
        }
        else {
            return IkiWiki::SuccessReason->new("$page links to page matching $link")
                if match_glob($p, $link, %params);
        }
    }
    return IkiWiki::FailReason->new("$page does not link to $link");
} #}}}

sub match_backlink ($$;@) { #{{{
    match_link($_[1], $_[0], @_);
} #}}}

sub match_created_before ($$;@) { #{{{
    my $page=shift;
    my $testpage=shift;

    if (exists $IkiWiki::pagectime{$testpage}) {
        if ($IkiWiki::pagectime{$page} < $IkiWiki::pagectime{$testpage}) {
            IkiWiki::SuccessReason->new("$page created before $testpage");
        }
        else {
            IkiWiki::FailReason->new("$page not created before $testpage");
        }
    }
    else {
        return IkiWiki::FailReason->new("$testpage has no ctime");
    }
} #}}}

sub match_created_after ($$;@) { #{{{
    my $page=shift;
    my $testpage=shift;

    if (exists $IkiWiki::pagectime{$testpage}) {
        if ($IkiWiki::pagectime{$page} > $IkiWiki::pagectime{$testpage}) {
            IkiWiki::SuccessReason->new("$page created after $testpage");
        }
        else {
            IkiWiki::FailReason->new("$page not created after $testpage");
        }
    }
    else {
        return IkiWiki::FailReason->new("$testpage has no ctime");
    }
} #}}}

sub match_creation_day ($$;@) { #{{{
    if ((gmtime($IkiWiki::pagectime{shift()}))[3] == shift) {
        return IkiWiki::SuccessReason->new("creation_day matched");
    }
    else {
        return IkiWiki::FailReason->new("creation_day did not match");
    }
} #}}}

sub match_creation_month ($$;@) { #{{{
    if ((gmtime($IkiWiki::pagectime{shift()}))[4] + 1 == shift) {
        return IkiWiki::SuccessReason->new("creation_month matched");
    }
    else {
        return IkiWiki::FailReason->new("creation_month did not match");
    }
} #}}}

sub match_creation_year ($$;@) { #{{{
    if ((gmtime($IkiWiki::pagectime{shift()}))[5] + 1900 == shift) {
        return IkiWiki::SuccessReason->new("creation_year matched");
    }
    else {
        return IkiWiki::FailReason->new("creation_year did not match");
    }
} #}}}

sub match_user ($$;@) { #{{{
    shift;
    my $user=shift;
    my %params=@_;

    return IkiWiki::FailReason->new("cannot match user") unless exists $params{user};
    if ($user eq $params{user}) {
        return IkiWiki::SuccessReason->new("user is $user")
    }
    else {
        return IkiWiki::FailReason->new("user is not $user");
    }
} #}}}

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