path: root/IkiWiki/Plugin/comments.pm

#!/usr/bin/perl
# Copyright © 2006-2008 Joey Hess <joey@ikiwiki.info>
# Copyright © 2008 Simon McVittie <http://smcv.pseudorandom.co.uk/>
# Licensed under the GNU GPL, version 2, or any later version published by the
# Free Software Foundation
package IkiWiki::Plugin::comments;

use warnings;
use strict;
use IkiWiki 3.00;
use Encode;
use POSIX qw(strftime);

use constant PREVIEW => "Preview";
use constant POST_COMMENT => "Post comment";
use constant CANCEL => "Cancel";

my $postcomment;
my %commentstate;

sub import {
    hook(type => "checkconfig", id => 'comments',  call => \&checkconfig);
    hook(type => "getsetup", id => 'comments',  call => \&getsetup);
    hook(type => "preprocess", id => 'comment', call => \&preprocess);
    hook(type => "preprocess", id => 'commentmoderation', call => \&preprocess_moderation);
    # here for backwards compatability with old comments
    hook(type => "preprocess", id => '_comment', call => \&preprocess);
    hook(type => "sessioncgi", id => 'comment', call => \&sessioncgi);
    hook(type => "htmlize", id => "_comment", call => \&htmlize);
    hook(type => "htmlize", id => "_comment_pending",
        call => \&htmlize_pending);
    hook(type => "pagetemplate", id => "comments", call => \&pagetemplate);
    hook(type => "formbuilder_setup", id => "comments",
        call => \&formbuilder_setup);
    # Load goto to fix up user page links for logged-in commenters
    IkiWiki::loadplugin("goto");
    IkiWiki::loadplugin("inline");
}

sub getsetup () {
    return
        plugin => {
            safe => 1,
            rebuild => 1,
            section => "web",
        },
        comments_pagespec => {
            type => 'pagespec',
            example => 'blog/* and !*/Discussion',
            description => 'PageSpec of pages where comments are allowed',
            link => 'ikiwiki/PageSpec',
            safe => 1,
            rebuild => 1,
        },
        comments_closed_pagespec => {
            type => 'pagespec',
            example => 'blog/controversial or blog/flamewar',
            description => 'PageSpec of pages where posting new comments is not allowed',
            link => 'ikiwiki/PageSpec',
            safe => 1,
            rebuild => 1,
        },
        comments_pagename => {
            type => 'string',
            default => 'comment_',
            description => 'Base name for comments, e.g. "comment_" for pages like "sandbox/comment_12"',
            safe => 0, # manual page moving required
            rebuild => undef,
        },
        comments_allowdirectives => {
            type => 'boolean',
            example => 0,
            description => 'Interpret directives in comments?',
            safe => 1,
            rebuild => 0,
        },
        comments_allowauthor => {
            type => 'boolean',
            example => 0,
            description => 'Allow anonymous commenters to set an author name?',
            safe => 1,
            rebuild => 0,
        },
        comments_commit => {
            type => 'boolean',
            example => 1,
            description => 'commit comments to the VCS',
            # old uncommitted comments are likely to cause
            # confusion if this is changed
            safe => 0,
            rebuild => 0,
        },
}

sub checkconfig () {
    $config{comments_commit} = 1
        unless defined $config{comments_commit};
    $config{comments_pagespec} = ''
        unless defined $config{comments_pagespec};
    $config{comments_closed_pagespec} = ''
        unless defined $config{comments_closed_pagespec};
    $config{comments_pagename} = 'comment_'
        unless defined $config{comments_pagename};
}

sub htmlize {
    my %params = @_;
    return $params{content};
}

sub htmlize_pending {
    my %params = @_;
    return sprintf(gettext("this comment needs %s"),
        '<a href="'.
        IkiWiki::cgiurl(do => "commentmoderation").'">'.
        gettext("moderation").'</a>');
}

# FIXME: copied verbatim from meta
sub safeurl ($) {
    my $url=shift;
    if (exists $IkiWiki::Plugin::htmlscrubber::{safe_url_regexp} &&
        defined $IkiWiki::Plugin::htmlscrubber::safe_url_regexp) {
        return $url=~/$IkiWiki::Plugin::htmlscrubber::safe_url_regexp/;
    }
    else {
        return 1;
    }
}

sub preprocess {
    my %params = @_;
    my $page = $params{page};

    my $format = $params{format};
    if (defined $format && ! exists $IkiWiki::hooks{htmlize}{$format}) {
        error(sprintf(gettext("unsupported page format %s"), $format));
    }

    my $content = $params{content};
    if (! defined $content) {
        error(gettext("comment must have content"));
    }
    $content =~ s/\\"/"/g;

    if ($config{comments_allowdirectives}) {
        $content = IkiWiki::preprocess($page, $params{destpage},
            $content);
    }

    # no need to bother with htmlize if it's just HTML
    $content = IkiWiki::htmlize($page, $params{destpage}, $format, $content)
        if defined $format;

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

    # set metadata, possibly overriding [[!meta]] directives from the
    # comment itself

    my $commentuser;
    my $commentip;
    my $commentauthor;
    my $commentauthorurl;
    my $commentopenid;
    if (defined $params{username}) {
        $commentuser = $params{username};

        my $oiduser = eval { IkiWiki::openiduser($commentuser) };

        if (defined $oiduser) {
            # looks like an OpenID
            $commentauthorurl = $commentuser;
            $commentauthor = (defined $params{nickname} && length $params{nickname}) ? $params{nickname} : $oiduser;
            $commentopenid = $commentuser;
        }
        else {
            $commentauthorurl = IkiWiki::cgiurl(
                do => 'goto',
                page => IkiWiki::userpage($commentuser)
            );

            $commentauthor = $commentuser;
        }
    }
    else {
        if (defined $params{ip}) {
            $commentip = $params{ip};
        }
        $commentauthor = gettext("Anonymous");
    }

    $commentstate{$page}{commentuser} = $commentuser;
    $commentstate{$page}{commentopenid} = $commentopenid;
    $commentstate{$page}{commentip} = $commentip;
    $commentstate{$page}{commentauthor} = $commentauthor;
    $commentstate{$page}{commentauthorurl} = $commentauthorurl;
    if (! defined $pagestate{$page}{meta}{author}) {
        $pagestate{$page}{meta}{author} = $commentauthor;
    }
    if (! defined $pagestate{$page}{meta}{authorurl}) {
        $pagestate{$page}{meta}{authorurl} = $commentauthorurl;
    }

    if ($config{comments_allowauthor}) {
        if (defined $params{claimedauthor}) {
            $pagestate{$page}{meta}{author} = $params{claimedauthor};
        }

        if (defined $params{url}) {
            my $url=$params{url};

            eval q{use URI::Heuristic}; 
            if (! $@) {
                $url=URI::Heuristic::uf_uristr($url);
            }

            if (safeurl($url)) {
                $pagestate{$page}{meta}{authorurl} = $url;
            }
        }
    }
    else {
        $pagestate{$page}{meta}{author} = $commentauthor;
        $pagestate{$page}{meta}{authorurl} = $commentauthorurl;
    }

    if (defined $params{subject}) {
        # decode title the same way meta does
        eval q{use HTML::Entities};
        $pagestate{$page}{meta}{title} = decode_entities($params{subject});
    }

    if ($params{page} =~ m/\/\Q$config{comments_pagename}\E\d+_/) {
        $pagestate{$page}{meta}{permalink} = urlto(IkiWiki::dirname($params{page}), undef, 1).
            "#".page_to_id($params{page});
    }

    eval q{use Date::Parse};
    if (! $@) {
        my $time = str2time($params{date});
        $IkiWiki::pagectime{$page} = $time if defined $time;
    }

    return $content;
}

sub preprocess_moderation {
    my %params = @_;

    $params{desc}=gettext("Comment Moderation")
        unless defined $params{desc};

    if (length $config{cgiurl}) {
        return '<a href="'.
            IkiWiki::cgiurl(do => 'commentmoderation').
            '">'.$params{desc}.'</a>';
    }
    else {
        return $params{desc};
    }
}

sub sessioncgi ($$) {
    my $cgi=shift;
    my $session=shift;

    my $do = $cgi->param('do');
    if ($do eq 'comment') {
        editcomment($cgi, $session);
    }
    elsif ($do eq 'commentmoderation') {
        commentmoderation($cgi, $session);
    }
    elsif ($do eq 'commentsignin') {
        IkiWiki::cgi_signin($cgi, $session);
        exit;
    }
}

# Mostly cargo-culted from IkiWiki::plugin::editpage
sub editcomment ($$) {
    my $cgi=shift;
    my $session=shift;

    IkiWiki::decode_cgi_utf8($cgi);

    eval q{use CGI::FormBuilder};
    error($@) if $@;

    my @buttons = (POST_COMMENT, PREVIEW, CANCEL);
    my $form = CGI::FormBuilder->new(
        fields => [qw{do sid page subject editcontent type author url}],
        charset => 'utf-8',
        method => 'POST',
        required => [qw{editcontent}],
        javascript => 0,
        params => $cgi,
        action => $config{cgiurl},
        header => 0,
        table => 0,
        template => { template('editcomment.tmpl') },
    );

    IkiWiki::decode_form_utf8($form);
    IkiWiki::run_hooks(formbuilder_setup => sub {
            shift->(title => "comment", form => $form, cgi => $cgi,
                session => $session, buttons => \@buttons);
        });
    IkiWiki::decode_form_utf8($form);

    my $type = $form->param('type');
    if (defined $type && length $type && $IkiWiki::hooks{htmlize}{$type}) {
        $type = IkiWiki::possibly_foolish_untaint($type);
    }
    else {
        $type = $config{default_pageext};
    }


    my @page_types;
    if (exists $IkiWiki::hooks{htmlize}) {
        foreach my $key (grep { !/^_/ } keys %{$IkiWiki::hooks{htmlize}}) {
            push @page_types, [$key, $IkiWiki::hooks{htmlize}{$key}{longname} || $key];
        }
    }
    @page_types=sort @page_types;

    $form->field(name => 'do', type => 'hidden');
    $form->field(name => 'sid', type => 'hidden', value => $session->id,
        force => 1);
    $form->field(name => 'page', type => 'hidden');
    $form->field(name => 'subject', type => 'text', size => 72);
    $form->field(name => 'editcontent', type => 'textarea', rows => 10);
    $form->field(name => "type", value => $type, force => 1,
        type => 'select', options => \@page_types);

    $form->tmpl_param(username => $session->param('name'));

    if ($config{comments_allowauthor} and
        ! defined $session->param('name')) {
        $form->tmpl_param(allowauthor => 1);
        $form->field(name => 'author', type => 'text', size => '40');
        $form->field(name => 'url', type => 'text', size => '40');
    }
    else {
        $form->tmpl_param(allowauthor => 0);
        $form->field(name => 'author', type => 'hidden', value => '',
            force => 1);
        $form->field(name => 'url', type => 'hidden', value => '',
            force => 1);
    }

    if (! defined $session->param('name')) {
        # Make signinurl work and return here.
        $form->tmpl_param(signinurl => IkiWiki::cgiurl(do => 'commentsignin'));
        $session->param(postsignin => $ENV{QUERY_STRING});
        IkiWiki::cgi_savesession($session);
    }

    # The untaint is OK (as in editpage) because we're about to pass
    # it to file_pruned anyway
    my $page = $form->field('page');
    $page = IkiWiki::possibly_foolish_untaint($page);
    if (! defined $page || ! length $page ||
        IkiWiki::file_pruned($page)) {
        error(gettext("bad page name"));
    }

    my $baseurl = urlto($page, undef, 1);

    $form->title(sprintf(gettext("commenting on %s"),
            IkiWiki::pagetitle($page)));

    $form->tmpl_param('helponformattinglink',
        htmllink($page, $page, 'ikiwiki/formatting',
            noimageinline => 1,
            linktext => 'FormattingHelp'),
            allowdirectives => $config{allow_directives});

    if ($form->submitted eq CANCEL) {
        # bounce back to the page they wanted to comment on, and exit.
        # CANCEL need not be considered in future
        IkiWiki::redirect($cgi, urlto($page, undef, 1));
        exit;
    }

    if (not exists $pagesources{$page}) {
        error(sprintf(gettext(
            "page '%s' doesn't exist, so you can't comment"),
            $page));
    }

    if (pagespec_match($page, $config{comments_closed_pagespec},
        location => $page)) {
        error(sprintf(gettext(
            "comments on page '%s' are closed"),
            $page));
    }

    # Set a flag to indicate that we're posting a comment,
    # so that postcomment() can tell it should match.
    $postcomment=1;
    IkiWiki::check_canedit($page, $cgi, $session);
    $postcomment=0;

    my $content = "[[!comment format=$type\n";

    if (defined $session->param('name')) {
        my $username = $session->param('name');
        $username =~ s/"/&quot;/g;
        $content .= " username=\"$username\"\n";
    }
    if (defined $session->param('nickname')) {
        my $nickname = $session->param('nickname');
        $nickname =~ s/"/&quot;/g;
        $content .= " nickname=\"$nickname\"\n";
    }
    elsif (defined $session->remote_addr()) {
        my $ip = $session->remote_addr();
        if ($ip =~ m/^([.0-9]+)$/) {
            $content .= " ip=\"$1\"\n";
        }
    }

    if ($config{comments_allowauthor}) {
        my $author = $form->field('author');
        if (defined $author && length $author) {
            $author =~ s/"/&quot;/g;
            $content .= " claimedauthor=\"$author\"\n";
        }
        my $url = $form->field('url');
        if (defined $url && length $url) {
            $url =~ s/"/&quot;/g;
            $content .= " url=\"$url\"\n";
        }
    }

    my $subject = $form->field('subject');
    if (defined $subject && length $subject) {
        $subject =~ s/"/&quot;/g;
    }
    else {
        $subject = "comment ".(num_comments($page, $config{srcdir}) + 1);
    }
    $content .= " subject=\"$subject\"\n";

    $content .= " date=\"" . decode_utf8(strftime('%Y-%m-%dT%H:%M:%SZ', gmtime)) . "\"\n";

    my $editcontent = $form->field('editcontent');
    $editcontent="" if ! defined $editcontent;
    $editcontent =~ s/\r\n/\n/g;
    $editcontent =~ s/\r/\n/g;
    $editcontent =~ s/"/\\"/g;
    $content .= " content=\"\"\"\n$editcontent\n\"\"\"]]\n";

    my $location=unique_comment_location($page, $content, $config{srcdir});

    # This is essentially a simplified version of editpage:
    # - the user does not control the page that's created, only the parent
    # - it's always a create operation, never an edit
    # - this means that conflicts should never happen
    # - this means that if they do, rocks fall and everyone dies

    if ($form->submitted eq PREVIEW) {
        my $preview=previewcomment($content, $location, $page, time);
        IkiWiki::run_hooks(format => sub {
            $preview = shift->(page => $page,
                content => $preview);
        });
        $form->tmpl_param(page_preview => $preview);
    }
    else {
        $form->tmpl_param(page_preview => "");
    }

    if ($form->submitted eq POST_COMMENT && $form->validate) {
        IkiWiki::checksessionexpiry($cgi, $session);
        
        $postcomment=1;
        my $ok=IkiWiki::check_content(content => $form->field('editcontent'),
            subject => $form->field('subject'),
            $config{comments_allowauthor} ? (
                author => $form->field('author'),
                url => $form->field('url'),
            ) : (),
            page => $location,
            cgi => $cgi,
            session => $session,
            nonfatal => 1,
        );
        $postcomment=0;

        if (! $ok) {
            $location=unique_comment_location($page, $content, $config{srcdir}, "._comment_pending");
            writefile("$location._comment_pending", $config{srcdir}, $content);

            # Refresh so anything that deals with pending
            # comments can be updated.
            require IkiWiki::Render;
            IkiWiki::refresh();
            IkiWiki::saveindex();

            IkiWiki::printheader($session);
            print IkiWiki::misctemplate(gettext(gettext("comment stored for moderation")),
                "<p>".
                gettext("Your comment will be posted after moderator review").
                "</p>");
            exit;
        }

        # FIXME: could probably do some sort of graceful retry
        # on error? Would require significant unwinding though
        my $file = "$location._comment";
        writefile($file, $config{srcdir}, $content);

        my $conflict;

        if ($config{rcs} and $config{comments_commit}) {
            my $message = gettext("Added a comment");
            if (defined $form->field('subject') &&
                length $form->field('subject')) {
                $message = sprintf(
                    gettext("Added a comment: %s"),
                    $form->field('subject'));
            }

            IkiWiki::rcs_add($file);
            IkiWiki::disable_commit_hook();
            $conflict = IkiWiki::rcs_commit_staged(
                message => $message,
                session => $session,
            );
            IkiWiki::enable_commit_hook();
            IkiWiki::rcs_update();
        }

        # Now we need a refresh
        require IkiWiki::Render;
        IkiWiki::refresh();
        IkiWiki::saveindex();

        # this should never happen, unless a committer deliberately
        # breaks it or something
        error($conflict) if defined $conflict;

        # Jump to the new comment on the page.
        # The trailing question mark tries to avoid broken
        # caches and get the most recent version of the page.
        IkiWiki::redirect($cgi, urlto($page, undef, 1).
            "?updated#".page_to_id($location));

    }
    else {
        IkiWiki::showform ($form, \@buttons, $session, $cgi,
            forcebaseurl => $baseurl, page => $page);
    }

    exit;
}

sub commentmoderation ($$) {
    my $cgi=shift;
    my $session=shift;

    IkiWiki::needsignin($cgi, $session);
    if (! IkiWiki::is_admin($session->param("name"))) {
        error(gettext("you are not logged in as an admin"));
    }

    IkiWiki::decode_cgi_utf8($cgi);
    
    if (defined $cgi->param('sid')) {
        IkiWiki::checksessionexpiry($cgi, $session);

        my $rejectalldefer=$cgi->param('rejectalldefer');

        my %vars=$cgi->Vars;
        my $added=0;
        foreach my $id (keys %vars) {
            if ($id =~ /(.*)\._comment(?:_pending)?$/) {
                $id=decode_utf8($id);
                my $action=$cgi->param($id);
                next if $action eq 'Defer' && ! $rejectalldefer;

                # Make sure that the id is of a legal
                # pending comment.
                my ($f) = $id =~ /$config{wiki_file_regexp}/;
                if (! defined $f || ! length $f ||
                    IkiWiki::file_pruned($f)) {
                    error("illegal file");
                }

                my $page=IkiWiki::dirname($f);
                my $file="$config{srcdir}/$f";
                if (! -e $file) {
                    # old location
                    $file="$config{wikistatedir}/comments_pending/".$f;
                }

                if ($action eq 'Accept') {
                    my $content=eval { readfile($file) };
                    next if $@; # file vanished since form was displayed
                    my $dest=unique_comment_location($page, $content, $config{srcdir})."._comment";
                    writefile($dest, $config{srcdir}, $content);
                    if ($config{rcs} and $config{comments_commit}) {
                        IkiWiki::rcs_add($dest);
                    }
                    $added++;
                }

                require IkiWiki::Render;
                IkiWiki::prune($file);
            }
        }

        if ($added) {
            my $conflict;
            if ($config{rcs} and $config{comments_commit}) {
                my $message = gettext("Comment moderation");
                IkiWiki::disable_commit_hook();
                $conflict=IkiWiki::rcs_commit_staged(
                    message => $message,
                    session => $session,
                );
                IkiWiki::enable_commit_hook();
                IkiWiki::rcs_update();
            }
        
            # Now we need a refresh
            require IkiWiki::Render;
            IkiWiki::refresh();
            IkiWiki::saveindex();
        
            error($conflict) if defined $conflict;
        }
    }

    my @comments=map {
        my ($id, $dir, $ctime)=@{$_};
        my $content=readfile("$dir/$id");
        my $preview=previewcomment($content, $id,
            $id, $ctime);
        {
            id => $id,
            view => $preview,
        }
    } sort { $b->[2] <=> $a->[2] } comments_pending();

    my $template=template("commentmoderation.tmpl");
    $template->param(
        sid => $session->id,
        comments => \@comments,
    );
    IkiWiki::printheader($session);
    my $out=$template->output;
    IkiWiki::run_hooks(format => sub {
        $out = shift->(page => "", content => $out);
    });
    print IkiWiki::misctemplate(gettext("comment moderation"), $out);
    exit;
}

sub formbuilder_setup (@) {
    my %params=@_;

    my $form=$params{form};
    if ($form->title eq "preferences" &&
        IkiWiki::is_admin($params{session}->param("name"))) {
        push @{$params{buttons}}, "Comment Moderation";
        if ($form->submitted && $form->submitted eq "Comment Moderation") {
            commentmoderation($params{cgi}, $params{session});
        }
    }
}

sub comments_pending () {
    my @ret;

    eval q{use File::Find};
    error($@) if $@;
    eval q{use Cwd};
    error($@) if $@;
    my $origdir=getcwd();

    my $find_comments=sub {
        my $dir=shift;
        my $extension=shift;
        return unless -d $dir;

        chdir($dir) || die "chdir $dir: $!";

        find({
            no_chdir => 1,
            wanted => sub {
                my $file=decode_utf8($_);
                $file=~s/^\.\///;
                return if ! length $file || IkiWiki::file_pruned($file)
                    || -l $_ || -d _ || $file !~ /\Q$extension\E$/;
                my ($f) = $file =~ /$config{wiki_file_regexp}/; # untaint
                if (defined $f) {
                    my $ctime=(stat($_))[10];
                    push @ret, [$f, $dir, $ctime];
                }
            }
        }, ".");

        chdir($origdir) || die "chdir $origdir: $!";
    };
    
    $find_comments->($config{srcdir}, "._comment_pending");
    # old location
    $find_comments->("$config{wikistatedir}/comments_pending/",
        "._comment");

    return @ret;
}

sub previewcomment ($$$) {
    my $content=shift;
    my $location=shift;
    my $page=shift;
    my $time=shift;

    # Previewing a comment should implicitly enable comment posting mode.
    my $oldpostcomment=$postcomment;
    $postcomment=1;

    my $preview = IkiWiki::htmlize($location, $page, '_comment',
            IkiWiki::linkify($location, $page,
            IkiWiki::preprocess($location, $page,
            IkiWiki::filter($location, $page, $content), 0, 1)));

    my $template = template("comment.tmpl");
    $template->param(content => $preview);
    $template->param(ctime => displaytime($time, undef, 1));
    $template->param(html5 => $config{html5});

    IkiWiki::run_hooks(pagetemplate => sub {
        shift->(page => $location,
            destpage => $page,
            template => $template);
    });

    $template->param(have_actions => 0);

    $postcomment=$oldpostcomment;

    return $template->output;
}

sub commentsshown ($) {
    my $page=shift;

    return ! pagespec_match($page, "comment(*)",
                            location => $page) &&
           pagespec_match($page, $config{comments_pagespec},
                          location => $page);
}

sub commentsopen ($) {
    my $page = shift;

    return length $config{cgiurl} > 0 &&
           (! length $config{comments_closed_pagespec} ||
            ! pagespec_match($page, $config{comments_closed_pagespec},
                             location => $page));
}

sub pagetemplate (@) {
    my %params = @_;

    my $page = $params{page};
    my $template = $params{template};
    my $shown = ($template->query(name => 'commentslink') ||
                 $template->query(name => 'commentsurl') ||
                 $template->query(name => 'atomcommentsurl') ||
                 $template->query(name => 'comments')) &&
                commentsshown($page);

    if ($template->query(name => 'comments')) {
        my $comments = undef;
        if ($shown) {
            $comments = IkiWiki::preprocess_inline(
                pages => "comment($page)",
                template => 'comment',
                show => 0,
                reverse => 'yes',
                page => $page,
                destpage => $params{destpage},
                feedfile => 'comments',
                emptyfeeds => 'no',
            );
        }

        if (defined $comments && length $comments) {
            $template->param(comments => $comments);
        }

        if ($shown && commentsopen($page)) {
            $template->param(addcommenturl => addcommenturl($page));
        }
    }

    if ($shown) {
        if ($template->query(name => 'commentsurl')) {
            $template->param(commentsurl =>
                urlto($page, undef, 1).'#comments');
        }

        if ($template->query(name => 'atomcommentsurl') && $config{usedirs}) {
            # This will 404 until there are some comments, but I
            # think that's probably OK...
            $template->param(atomcommentsurl =>
                urlto($page, undef, 1).'comments.atom');
        }

        if ($template->query(name => 'commentslink')) {
            my $num=num_comments($page, $config{srcdir});
            my $link;
            if ($num > 0) {
                $link = htmllink($page, $params{destpage}, $page,
                    linktext => sprintf(ngettext("%i comment", "%i comments", $num), $num),
                    anchor => "comments",
                    noimageinline => 1
                );
            }
            elsif (commentsopen($page)) {
                $link = "<a href=\"".addcommenturl($page)."\">".
                    #translators: Here "Comment" is a verb;
                    #translators: the user clicks on it to
                    #translators: post a comment.
                    gettext("Comment").
                    "</a>";
            }
            $template->param(commentslink => $link)
                if defined $link;
        }
    }

    # everything below this point is only relevant to the comments
    # themselves
    if (!exists $commentstate{$page}) {
        return;
    }
    
    if ($template->query(name => 'commentid')) {
        $template->param(commentid => page_to_id($page));
    }

    if ($template->query(name => 'commentuser')) {
        $template->param(commentuser =>
            $commentstate{$page}{commentuser});
    }

    if ($template->query(name => 'commentopenid')) {
        $template->param(commentopenid =>
            $commentstate{$page}{commentopenid});
    }

    if ($template->query(name => 'commentip')) {
        $template->param(commentip =>
            $commentstate{$page}{commentip});
    }

    if ($template->query(name => 'commentauthor')) {
        $template->param(commentauthor =>
            $commentstate{$page}{commentauthor});
    }

    if ($template->query(name => 'commentauthorurl')) {
        $template->param(commentauthorurl =>
            $commentstate{$page}{commentauthorurl});
    }

    if ($template->query(name => 'removeurl') &&
        IkiWiki::Plugin::remove->can("check_canremove") &&
        length $config{cgiurl}) {
        $template->param(removeurl => IkiWiki::cgiurl(do => 'remove',
            page => $page));
        $template->param(have_actions => 1);
    }
}

sub addcommenturl ($) {
    my $page=shift;

    return IkiWiki::cgiurl(do => 'comment', page => $page);
}

sub num_comments ($$) {
    my $page=shift;
    my $dir=shift;

    my @comments=glob("$dir/$page/$config{comments_pagename}*._comment");
    return int @comments;
}

sub unique_comment_location ($$$$) {
    my $page=shift;
    eval q{use Digest::MD5 'md5_hex'};
    error($@) if $@;
    my $content_md5=md5_hex(Encode::encode_utf8(shift));
    my $dir=shift;
    my $ext=shift || "._comment";

    my $location;
    my $i = num_comments($page, $dir);
    do {
        $i++;
        $location = "$page/$config{comments_pagename}${i}_${content_md5}";
    } while (-e "$dir/$location$ext");

    return $location;
}

sub page_to_id ($) {
    # Converts a comment page name into a unique, legal html id
    # attribute value, that can be used as an anchor to link to the
    # comment.
    my $page=shift;

    eval q{use Digest::MD5 'md5_hex'};
    error($@) if $@;

    return "comment-".md5_hex(Encode::encode_utf8(($page)));
}
    
package IkiWiki::PageSpec;

sub match_postcomment ($$;@) {
    my $page = shift;
    my $glob = shift;

    if (! $postcomment) {
        return IkiWiki::FailReason->new("not posting a comment");
    }
    return match_glob($page, $glob, @_);
}

sub match_comment ($$;@) {
    my $page = shift;
    my $glob = shift;

    if (! $postcomment) {
        # To see if it's a comment, check the source file type.
        # Deal with comments that were just deleted.
        my $source=exists $IkiWiki::pagesources{$page} ?
            $IkiWiki::pagesources{$page} :
            $IkiWiki::delpagesources{$page};
        my $type=defined $source ? IkiWiki::pagetype($source) : undef;
        if (! defined $type || $type ne "_comment") {
            return IkiWiki::FailReason->new("$page is not a comment");
        }
    }

    return match_glob($page, "$glob/*", internal => 1, @_);
}

sub match_comment_pending ($$;@) {
    my $page = shift;
    my $glob = shift;
    
    my $source=exists $IkiWiki::pagesources{$page} ?
        $IkiWiki::pagesources{$page} :
        $IkiWiki::delpagesources{$page};
    my $type=defined $source ? IkiWiki::pagetype($source) : undef;
    if (! defined $type || $type ne "_comment_pending") {
        return IkiWiki::FailReason->new("$page is not a pending comment");
    }

    return match_glob($page, "$glob/*", internal => 1, @_);
}

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