path: root/IkiWiki/Plugin/po.pm

#!/usr/bin/perl
# .po as a wiki page type
# Licensed under GPL v2 or greater
# Copyright (C) 2008-2009 intrigeri <intrigeri@boum.org>
# inspired by the GPL'd po4a-translate,
# which is Copyright 2002, 2003, 2004 by Martin Quinson (mquinson#debian.org)
package IkiWiki::Plugin::po;

use warnings;
use strict;
use IkiWiki 3.00;
use Encode;
use Locale::Po4a::Common qw(nowrapi18n);
use Locale::Po4a::Chooser;
use Locale::Po4a::Po;
use File::Basename;
use File::Copy;
use File::Spec;
use File::Temp;
use Memoize;
use UNIVERSAL;

my %translations;
my @origneedsbuild;
my %origsubs;

memoize("istranslatable");
memoize("_istranslation");
memoize("percenttranslated");

sub import {
    hook(type => "getsetup", id => "po", call => \&getsetup);
    hook(type => "checkconfig", id => "po", call => \&checkconfig);
    hook(type => "needsbuild", id => "po", call => \&needsbuild);
    hook(type => "scan", id => "po", call => \&scan, last =>1);
    hook(type => "filter", id => "po", call => \&filter);
    hook(type => "htmlize", id => "po", call => \&htmlize);
    hook(type => "pagetemplate", id => "po", call => \&pagetemplate, last => 1);
    hook(type => "rename", id => "po", call => \&renamepages, first => 1);
    hook(type => "delete", id => "po", call => \&mydelete);
    hook(type => "change", id => "po", call => \&change);
    hook(type => "checkcontent", id => "po", call => \&checkcontent);
    hook(type => "canremove", id => "po", call => \&canremove);
    hook(type => "canrename", id => "po", call => \&canrename);
    hook(type => "editcontent", id => "po", call => \&editcontent);
    hook(type => "formbuilder_setup", id => "po", call => \&formbuilder_setup, last => 1);
    hook(type => "formbuilder", id => "po", call => \&formbuilder);

    $origsubs{'bestlink'}=\&IkiWiki::bestlink;
    inject(name => "IkiWiki::bestlink", call => \&mybestlink);
    $origsubs{'beautify_urlpath'}=\&IkiWiki::beautify_urlpath;
    inject(name => "IkiWiki::beautify_urlpath", call => \&mybeautify_urlpath);
    $origsubs{'targetpage'}=\&IkiWiki::targetpage;
    inject(name => "IkiWiki::targetpage", call => \&mytargetpage);
    $origsubs{'urlto'}=\&IkiWiki::urlto;
    inject(name => "IkiWiki::urlto", call => \&myurlto);
    $origsubs{'cgiurl'}=\&IkiWiki::cgiurl;
    inject(name => "IkiWiki::cgiurl", call => \&mycgiurl);
}


# ,----
# | Table of contents
# `----

# 1. Hooks
# 2. Injected functions
# 3. Blackboxes for private data
# 4. Helper functions
# 5. PageSpecs


# ,----
# | Hooks
# `----

sub getsetup () {
    return
        plugin => {
            safe => 0,
            rebuild => 1,
        },
        po_master_language => {
            type => "string",
            example => {
                'code' => 'en',
                'name' => 'English'
            },
            description => "master language (non-PO files)",
            safe => 1,
            rebuild => 1,
        },
        po_slave_languages => {
            type => "string",
            example => {
                'fr' => 'Français',
                'es' => 'Castellano',
                'de' => 'Deutsch'
            },
            description => "slave languages (PO files)",
            safe => 1,
            rebuild => 1,
        },
        po_translatable_pages => {
            type => "pagespec",
            example => "!*/Discussion",
            description => "PageSpec controlling which pages are translatable",
            link => "ikiwiki/PageSpec",
            safe => 1,
            rebuild => 1,
        },
        po_link_to => {
            type => "string",
            example => "current",
            description => "internal linking behavior (default/current/negotiated)",
            safe => 1,
            rebuild => 1,
        },
}

sub checkconfig () {
    foreach my $field (qw{po_master_language po_slave_languages}) {
        if (! exists $config{$field} || ! defined $config{$field}) {
            error(sprintf(gettext("Must specify %s when using the %s plugin"),
                      $field, 'po'));
        }
    }
    if (! (keys %{$config{po_slave_languages}})) {
        error(gettext("At least one slave language must be defined ".
                  "in po_slave_languages when using the po plugin"));
    }
    map {
        islanguagecode($_)
            or error(sprintf(gettext("%s is not a valid language code"), $_));
    } ($config{po_master_language}{code}, keys %{$config{po_slave_languages}});
    if (! exists $config{po_translatable_pages} ||
        ! defined $config{po_translatable_pages}) {
        $config{po_translatable_pages}="";
    }
    if (! exists $config{po_link_to} ||
        ! defined $config{po_link_to}) {
        $config{po_link_to}='default';
    }
    elsif (! grep {
            $config{po_link_to} eq $_
        } ('default', 'current', 'negotiated')) {
        warn(sprintf(gettext('%s is not a valid value for po_link_to, falling back to po_link_to=default'),
                 $config{po_link_to}));
        $config{po_link_to}='default';
    }
    elsif ($config{po_link_to} eq "negotiated" && ! $config{usedirs}) {
        warn(gettext('po_link_to=negotiated requires usedirs to be enabled, falling back to po_link_to=default'));
        $config{po_link_to}='default';
    }
    push @{$config{wiki_file_prune_regexps}}, qr/\.pot$/;
}

sub needsbuild () {
    my $needsbuild=shift;

    # backup @needsbuild content so that change() can know whether
    # a given master page was rendered because its source file was changed
    @origneedsbuild=(@$needsbuild);

    flushmemoizecache();
    buildtranslationscache();

    # make existing translations depend on the corresponding master page
    foreach my $master (keys %translations) {
        map add_depends($_, $master), values %{otherlanguages($master)};
    }
}

# Massage the recorded state of internal links so that:
# - it matches the actually generated links, rather than the links as written
#   in the pages' source
# - backlinks are consistent in all cases
sub scan (@) {
    my %params=@_;
    my $page=$params{page};
    my $content=$params{content};

    return unless UNIVERSAL::can("IkiWiki::Plugin::link", "import");

    if (istranslation($page)) {
        foreach my $destpage (@{$links{$page}}) {
            if (istranslatable($destpage)) {
                # replace one occurence of $destpage in $links{$page}
                # (we only want to replace the one that was added by
                # IkiWiki::Plugin::link::scan, other occurences may be
                # there for other reasons)
                for (my $i=0; $i<@{$links{$page}}; $i++) {
                    if (@{$links{$page}}[$i] eq $destpage) {
                        @{$links{$page}}[$i] = $destpage . '.' . lang($page);
                        last;
                    }
                }
            }
        }
    }
    elsif (! istranslatable($page) && ! istranslation($page)) {
        foreach my $destpage (@{$links{$page}}) {
            if (istranslatable($destpage)) {
                # make sure any destpage's translations has
                # $page in its backlinks
                push @{$links{$page}},
                    values %{otherlanguages($destpage)};
            }
        }
    }
}

# We use filter to convert PO to the master page's format,
# since the rest of ikiwiki should not work on PO files.
sub filter (@) {
    my %params = @_;

    my $page = $params{page};
    my $destpage = $params{destpage};
    my $content = $params{content};
    if (istranslation($page) && ! alreadyfiltered($page, $destpage)) {
        $content = po_to_markup($page, $content);
        setalreadyfiltered($page, $destpage);
    }
    return $content;
}

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

    my $page = $params{page};
    my $content = $params{content};

    # ignore PO files this plugin did not create
    return $content unless istranslation($page);

    # force content to be htmlize'd as if it was the same type as the master page
    return IkiWiki::htmlize($page, $page,
        pagetype(srcfile($pagesources{masterpage($page)})),
        $content);
}

sub pagetemplate (@) {
    my %params=@_;
    my $page=$params{page};
    my $destpage=$params{destpage};
    my $template=$params{template};

    my ($masterpage, $lang) = istranslation($page);

    if (istranslation($page) && $template->query(name => "percenttranslated")) {
        $template->param(percenttranslated => percenttranslated($page));
    }
    if ($template->query(name => "istranslation")) {
        $template->param(istranslation => scalar istranslation($page));
    }
    if ($template->query(name => "istranslatable")) {
        $template->param(istranslatable => istranslatable($page));
    }
    if ($template->query(name => "HOMEPAGEURL")) {
        $template->param(homepageurl => homepageurl($page));
    }
    if ($template->query(name => "otherlanguages")) {
        $template->param(otherlanguages => [otherlanguagesloop($page)]);
        map add_depends($page, $_), (values %{otherlanguages($page)});
    }
    # Rely on IkiWiki::Render's genpage() to decide wether
    # a discussion link should appear on $page; this is not
    # totally accurate, though: some broken links may be generated
    # when cgiurl is disabled.
    # This compromise avoids some code duplication, and will probably
    # prevent future breakage when ikiwiki internals change.
    # Known limitations are preferred to future random bugs.
    if ($template->param('discussionlink') && istranslation($page)) {
        $template->param('discussionlink' => htmllink(
            $page,
            $destpage,
            $masterpage . '/' . gettext("Discussion"),
            noimageinline => 1,
            forcesubpage => 0,
            linktext => gettext("Discussion"),
        ));
    }
    # Remove broken parentlink to ./index.html on home page's translations.
    # It works because this hook has the "last" parameter set, to ensure it
    # runs after parentlinks' own pagetemplate hook.
    if ($template->param('parentlinks')
        && istranslation($page)
        && $masterpage eq "index") {
        $template->param('parentlinks' => []);
    }
} # }}}

# Add the renamed page translations to the list of to-be-renamed pages.
sub renamepages(@) {
    my %params = @_;

    my %torename = %{$params{torename}};
    my $session = $params{session};

    # Save the page(s) the user asked to rename, so that our
    # canrename hook can tell the difference between:
    #  - a translation being renamed as a consequence of its master page
    #    being renamed
    #  - a user trying to directly rename a translation
    # This is why this hook has to be run first, before the list of pages
    # to rename is modified by other plugins.
    my @orig_torename;
    @orig_torename=@{$session->param("po_orig_torename")}
        if defined $session->param("po_orig_torename");
    push @orig_torename, $torename{src};
    $session->param(po_orig_torename => \@orig_torename);
    IkiWiki::cgi_savesession($session);

    return () unless istranslatable($torename{src});

    my @ret;
    my %otherpages=%{otherlanguages($torename{src})};
    while (my ($lang, $otherpage) = each %otherpages) {
        push @ret, {
            src => $otherpage,
            srcfile => $pagesources{$otherpage},
            dest => otherlanguage($torename{dest}, $lang),
            destfile => $torename{dest}.".".$lang.".po",
            required => 0,
        };
    }
    return @ret;
}

sub mydelete(@) {
    my @deleted=@_;

    map { deletetranslations($_) } grep istranslatablefile($_), @deleted;
}

sub change(@) {
    my @rendered=@_;

    # All meta titles are first extracted at scan time, i.e. before we turn
    # PO files back into translated markdown; escaping of double-quotes in
    # PO files breaks the meta plugin's parsing enough to save ugly titles
    # to %pagestate at this time.
    #
    # Then, at render time, every page's passes on row through the Great
    # Rendering Chain (filter->preprocess->linkify->htmlize), and the meta
    # plugin's preprocess hook is this time in a position to correctly
    # extract the titles from slave pages.
    #
    # This is, unfortunately, too late: if the page A, linking to the page B,
    # is rendered before B, it will display the wrongly-extracted meta title
    # as the link text to B.
    #
    # On the one hand, such a corner case only happens on rebuild: on
    # refresh, every rendered page is fixed to contain correct meta titles.
    # On the other hand, it can take some time to get every page fixed.
    # We therefore re-render every rendered page after a rebuild to fix them
    # at once. As this more or less doubles the time needed to rebuild the
    # wiki, we do so only when really needed.

    if (@rendered
        && exists $config{rebuild} && defined $config{rebuild} && $config{rebuild}
        && UNIVERSAL::can("IkiWiki::Plugin::meta", "getsetup")
        && exists $config{meta_overrides_page_title}
        && defined $config{meta_overrides_page_title}
        && $config{meta_overrides_page_title}) {
        debug(sprintf(gettext("re-rendering all pages to fix meta titles")));
        resetalreadyfiltered();
        require IkiWiki::Render;
        foreach my $file (@rendered) {
            debug(sprintf(gettext("rendering %s"), $file));
            IkiWiki::render($file);
        }
    }

    my $updated_po_files=0;

    # Refresh/create POT and PO files as needed.
    foreach my $file (grep {istranslatablefile($_)} @rendered) {
        my $page=pagename($file);
        my $masterfile=srcfile($file);
        my $updated_pot_file=0;
        # Only refresh Pot file if it does not exist, or if
        # $pagesources{$page} was changed: don't if only the HTML was
        # refreshed, e.g. because of a dependency.
        if ((grep { $_ eq $pagesources{$page} } @origneedsbuild)
            || ! -e potfile($masterfile)) {
            refreshpot($masterfile);
            $updated_pot_file=1;
        }
        my @pofiles;
        map {
            push @pofiles, $_ if ($updated_pot_file || ! -e $_);
        } (pofiles($masterfile));
        if (@pofiles) {
            refreshpofiles($masterfile, @pofiles);
            map { IkiWiki::rcs_add($_) } @pofiles if $config{rcs};
            $updated_po_files=1;
        }
    }

    if ($updated_po_files) {
        commit_and_refresh(
            gettext("updated PO files"),
            "IkiWiki::Plugin::po::change");
    }
}

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

    if (istranslation($params{page})) {
        my $res = isvalidpo($params{content});
        if ($res) {
            return undef;
        }
        else {
            return "$res";
        }
    }
    return undef;
}

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

    if (istranslation($params{page})) {
        return gettext("Can not remove a translation. Removing the master page, ".
                   "though, removes its translations as well.");
    }
    return undef;
}

sub canrename (@) {
    my %params = @_;
    my $session = $params{session};

    if (istranslation($params{src})) {
        my $masterpage = masterpage($params{src});
        # Tell the difference between:
        #  - a translation being renamed as a consequence of its master page
        #    being renamed, which is allowed
        #  - a user trying to directly rename a translation, which is forbidden
        # by looking for the master page in the list of to-be-renamed pages we
        # saved early in the renaming process.
        my $orig_torename = $session->param("po_orig_torename");
        unless (grep { $_ eq $masterpage } @{$orig_torename}) {
            return gettext("Can not rename a translation. Renaming the master page, ".
                       "though, renames its translations as well.");
        }
    }
    return undef;
}

# As we're previewing or saving a page, the content may have
# changed, so tell the next filter() invocation it must not be lazy.
sub editcontent () {
    my %params=@_;

    unsetalreadyfiltered($params{page}, $params{page});
    return $params{content};
}

sub formbuilder_setup (@) {
    my %params=@_;
    my $form=$params{form};
    my $q=$params{cgi};

    return unless defined $form->field("do");

    if ($form->field("do") eq "create") {
        # Warn the user: new pages must be written in master language.
        my $template=template("pocreatepage.tmpl");
        $template->param(LANG => $config{po_master_language}{name});
        $form->tmpl_param(message => $template->output);
    }
    elsif ($form->field("do") eq "edit") {
        # Remove the rename/remove buttons on slave pages.
        # This has to be done after the rename/remove plugins have added
        # their buttons, which is why this hook must be run last.
        # The canrename/canremove hooks already ensure this is forbidden
        # at the backend level, so this is only UI sugar.
        if (istranslation($form->field("page"))) {
            map {
                for (my $i = 0; $i < @{$params{buttons}}; $i++) {
                    if (@{$params{buttons}}[$i] eq $_) {
                        delete  @{$params{buttons}}[$i];
                        last;
                    }
                }
            } qw(Rename Remove);
        }
    }
}

sub formbuilder (@) {
    my %params=@_;
    my $form=$params{form};
    my $q=$params{cgi};

    return unless defined $form->field("do");

    # Do not allow to create pages of type po: they are automatically created.
    # The main reason to do so is to bypass the "favor the type of linking page
    # on page creation" logic, which is unsuitable when a broken link is clicked
    # on a slave (PO) page.
    # This cannot be done in the formbuilder_setup hook as the list of types is
    # computed later.
    if ($form->field("do") eq "create") {
            foreach my $field ($form->field) {
            next unless "$field" eq "type";
            if ($field->type eq 'select') {
                # remove po from the list of types
                my @types = grep { $_ ne 'po' } $field->options;
                $field->options(\@types) if @types;
            }
        }
    }
}

# ,----
# | Injected functions
# `----

# Implement po_link_to 'current' and 'negotiated' settings.
sub mybestlink ($$) {
    my $page=shift;
    my $link=shift;

    my $res=$origsubs{'bestlink'}->(masterpage($page), $link);
    if (length $res
        && ($config{po_link_to} eq "current" || $config{po_link_to} eq "negotiated")
        && istranslatable($res)
        && istranslation($page)) {
        return $res . "." . lang($page);
    }
    return $res;
}

sub mybeautify_urlpath ($) {
    my $url=shift;

    my $res=$origsubs{'beautify_urlpath'}->($url);
    if ($config{po_link_to} eq "negotiated") {
        $res =~ s!/\Qindex.$config{po_master_language}{code}.$config{htmlext}\E$!/!;
        $res =~ s!/\Qindex.$config{htmlext}\E$!/!;
        map {
            $res =~ s!/\Qindex.$_.$config{htmlext}\E$!/!;
        } (keys %{$config{po_slave_languages}});
    }
    return $res;
}

sub mytargetpage ($$) {
    my $page=shift;
    my $ext=shift;

    if (istranslation($page) || istranslatable($page)) {
        my ($masterpage, $lang) = (masterpage($page), lang($page));
        if (! $config{usedirs} || $masterpage eq 'index') {
            return $masterpage . "." . $lang . "." . $ext;
        }
        else {
            return $masterpage . "/index." . $lang . "." . $ext;
        }
    }
    return $origsubs{'targetpage'}->($page, $ext);
}

sub myurlto ($$;$) {
    my $to=shift;
    my $from=shift;
    my $absolute=shift;

    # workaround hard-coded /index.$config{htmlext} in IkiWiki::urlto()
    if (! length $to
        && $config{po_link_to} eq "current"
        && istranslatable('index')) {
        return IkiWiki::beautify_urlpath(IkiWiki::baseurl($from) . "index." . lang($from) . ".$config{htmlext}");
    }
    # avoid using our injected beautify_urlpath if run by cgi_editpage,
    # so that one is redirected to the just-edited page rather than to the
    # negociated translation; to prevent unnecessary fiddling with caller/inject,
    # we only do so when our beautify_urlpath would actually do what we want to
    # avoid, i.e. when po_link_to = negotiated
    if ($config{po_link_to} eq "negotiated") {
        my @caller = caller(1);
        my $run_by_editpage = 0;
        $run_by_editpage = 1 if (exists $caller[3] && defined $caller[3]
                     && $caller[3] eq "IkiWiki::cgi_editpage");
        inject(name => "IkiWiki::beautify_urlpath", call => $origsubs{'beautify_urlpath'})
            if $run_by_editpage;
        my $res = $origsubs{'urlto'}->($to,$from,$absolute);
        inject(name => "IkiWiki::beautify_urlpath", call => \&mybeautify_urlpath)
            if $run_by_editpage;
        return $res;
    }
    else {
        return $origsubs{'urlto'}->($to,$from,$absolute)
    }
}

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

    # slave pages have no subpages
    if (istranslation($params{'from'})) {
        $params{'from'} = masterpage($params{'from'});
    }
    return $origsubs{'cgiurl'}->(%params);
}

# ,----
# | Blackboxes for private data
# `----

{
    my %filtered;

    sub alreadyfiltered($$) {
        my $page=shift;
        my $destpage=shift;

        return exists $filtered{$page}{$destpage}
             && $filtered{$page}{$destpage} eq 1;
    }

    sub setalreadyfiltered($$) {
        my $page=shift;
        my $destpage=shift;

        $filtered{$page}{$destpage}=1;
    }

    sub unsetalreadyfiltered($$) {
        my $page=shift;
        my $destpage=shift;

        if (exists $filtered{$page}{$destpage}) {
            delete $filtered{$page}{$destpage};
        }
    }

    sub resetalreadyfiltered() {
        undef %filtered;
    }
}

# ,----
# | Helper functions
# `----

sub maybe_add_leading_slash ($;$) {
    my $str=shift;
    my $add=shift;
    $add=1 unless defined $add;
    return '/' . $str if $add;
    return $str;
}

sub istranslatablefile ($) {
    my $file=shift;

    return 0 unless defined $file;
    return 0 if defined pagetype($file) && pagetype($file) eq 'po';
    return 0 if $file =~ /\.pot$/;
    return 0 unless -e "$config{srcdir}/$file"; # underlay dirs may be read-only
    return 1 if pagespec_match(pagename($file), $config{po_translatable_pages});
    return;
}

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

    $page=~s#^/##;
    return 1 if istranslatablefile($pagesources{$page});
    return;
}

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

    $page='' unless defined $page && length $page;
    my $hasleadingslash = ($page=~s#^/##);
    my $file=$pagesources{$page};
    return 0 unless defined $file
             && defined pagetype($file)
             && pagetype($file) eq 'po';
    return 0 if $file =~ /\.pot$/;

    my ($masterpage, $lang) = ($page =~ /(.*)[.]([a-z]{2})$/);
    return 0 unless defined $masterpage && defined $lang
             && length $masterpage && length $lang
             && defined $pagesources{$masterpage}
             && defined $config{po_slave_languages}{$lang};

    return (maybe_add_leading_slash($masterpage, $hasleadingslash), $lang)
        if istranslatable($masterpage);
}

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

    if (1 < (my ($masterpage, $lang) = _istranslation($page))) {
        my $hasleadingslash = ($masterpage=~s#^/##);
        $translations{$masterpage}{$lang}=$page unless exists $translations{$masterpage}{$lang};
        return (maybe_add_leading_slash($masterpage, $hasleadingslash), $lang);
    }
    return "";
}

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

    if ( 1 < (my ($masterpage, $lang) = _istranslation($page))) {
        return $masterpage;
    }
    return $page;
}

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

    if (1 < (my ($masterpage, $lang) = _istranslation($page))) {
        return $lang;
    }
    return $config{po_master_language}{code};
}

sub islanguagecode ($) {
    my $code=shift;

    return $code =~ /^[a-z]{2}$/;
}

sub otherlanguage ($$) {
    my $page=shift;
    my $code=shift;

    return masterpage($page) if $code eq $config{po_master_language}{code};
    return masterpage($page) . '.' . $code;
}

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

    my %ret;
    return \%ret unless istranslation($page) || istranslatable($page);
    my $curlang=lang($page);
    foreach my $lang
        ($config{po_master_language}{code}, keys %{$config{po_slave_languages}}) {
        next if $lang eq $curlang;
        $ret{$lang}=otherlanguage($page, $lang);
    }
    return \%ret;
}

sub potfile ($) {
    my $masterfile=shift;

    (my $name, my $dir, my $suffix) = fileparse($masterfile, qr/\.[^.]*/);
    $dir='' if $dir eq './';
    return File::Spec->catpath('', $dir, $name . ".pot");
}

sub pofile ($$) {
    my $masterfile=shift;
    my $lang=shift;

    (my $name, my $dir, my $suffix) = fileparse($masterfile, qr/\.[^.]*/);
    $dir='' if $dir eq './';
    return File::Spec->catpath('', $dir, $name . "." . $lang . ".po");
}

sub pofiles ($) {
    my $masterfile=shift;

    return map pofile($masterfile, $_), (keys %{$config{po_slave_languages}});
}

sub refreshpot ($) {
    my $masterfile=shift;

    my $potfile=potfile($masterfile);
    my %options = ("markdown" => (pagetype($masterfile) eq 'mdwn') ? 1 : 0);
    my $doc=Locale::Po4a::Chooser::new('text',%options);
    $doc->{TT}{utf_mode} = 1;
    $doc->{TT}{file_in_charset} = 'utf-8';
    $doc->{TT}{file_out_charset} = 'utf-8';
    $doc->read($masterfile);
    # let's cheat a bit to force porefs option to be passed to Locale::Po4a::Po;
    # this is undocument use of internal Locale::Po4a::TransTractor's data,
    # compulsory since this module prevents us from using the porefs option.
    $doc->{TT}{po_out}=Locale::Po4a::Po->new({ 'porefs' => 'none' });
    $doc->{TT}{po_out}->set_charset('utf-8');
    # do the actual work
    $doc->parse;
    IkiWiki::prep_writefile(basename($potfile),dirname($potfile));
    $doc->writepo($potfile);
}

sub refreshpofiles ($@) {
    my $masterfile=shift;
    my @pofiles=@_;

    my $potfile=potfile($masterfile);
    if (! -e $potfile) {
        error("po(refreshpofiles) ".sprintf(gettext("POT file (%s) does not exist"), $potfile));
    }

    foreach my $pofile (@pofiles) {
        IkiWiki::prep_writefile(basename($pofile),dirname($pofile));
        if (-e $pofile) {
            system("msgmerge", "-U", "--backup=none", $pofile, $potfile) == 0
                or error("po(refreshpofiles) ".
                     sprintf(gettext("failed to update %s"),
                         $pofile));
        }
        else {
            File::Copy::syscopy($potfile,$pofile)
                or error("po(refreshpofiles) ".
                     sprintf(gettext("failed to copy the POT file to %s"),
                         $pofile));
        }
    }
}

sub buildtranslationscache() {
    # use istranslation's side-effect
    map istranslation($_), (keys %pagesources);
}

sub resettranslationscache() {
    undef %translations;
}

sub flushmemoizecache() {
    Memoize::flush_cache("istranslatable");
    Memoize::flush_cache("_istranslation");
    Memoize::flush_cache("percenttranslated");
}

sub urlto_with_orig_beautiful_urlpath($$) {
    my $to=shift;
    my $from=shift;

    inject(name => "IkiWiki::beautify_urlpath", call => $origsubs{'beautify_urlpath'});
    my $res=urlto($to, $from);
    inject(name => "IkiWiki::beautify_urlpath", call => \&mybeautify_urlpath);

    return $res;
}

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

    $page=~s/^\///;
    return gettext("N/A") unless istranslation($page);
    my $file=srcfile($pagesources{$page});
    my $masterfile = srcfile($pagesources{masterpage($page)});
    my %options = (
        "markdown" => (pagetype($masterfile) eq 'mdwn') ? 1 : 0,
    );
    my $doc=Locale::Po4a::Chooser::new('text',%options);
    $doc->process(
        'po_in_name'    => [ $file ],
        'file_in_name'  => [ $masterfile ],
        'file_in_charset'  => 'utf-8',
        'file_out_charset' => 'utf-8',
    ) or error("po(percenttranslated) ".
           sprintf(gettext("failed to translate %s"), $page));
    my ($percent,$hit,$queries) = $doc->stats();
    $percent =~ s/\.[0-9]+$//;
    return $percent;
}

sub languagename ($) {
    my $code=shift;

    return $config{po_master_language}{name}
        if $code eq $config{po_master_language}{code};
    return $config{po_slave_languages}{$code}
        if defined $config{po_slave_languages}{$code};
    return;
}

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

    my @ret;
    my %otherpages=%{otherlanguages($page)};
    while (my ($lang, $otherpage) = each %otherpages) {
        if (istranslation($page) && masterpage($page) eq $otherpage) {
            push @ret, {
                url => urlto_with_orig_beautiful_urlpath($otherpage, $page),
                code => $lang,
                language => languagename($lang),
                master => 1,
            };
        }
        else {
            push @ret, {
                url => urlto_with_orig_beautiful_urlpath($otherpage, $page),
                code => $lang,
                language => languagename($lang),
                percent => percenttranslated($otherpage),
            }
        }
    }
    return sort {
            return -1 if $a->{code} eq $config{po_master_language}{code};
            return 1 if $b->{code} eq $config{po_master_language}{code};
            return $a->{language} cmp $b->{language};
        } @ret;
}

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

    return urlto('', $page);
}

sub deletetranslations ($) {
    my $deletedmasterfile=shift;

    my $deletedmasterpage=pagename($deletedmasterfile);
    my @todelete;
    map {
        my $file = newpagefile($deletedmasterpage.'.'.$_, 'po');
        my $absfile = "$config{srcdir}/$file";
        if (-e $absfile && ! -l $absfile && ! -d $absfile) {
            push @todelete, $file;
        }
    } keys %{$config{po_slave_languages}};

    map {
        if ($config{rcs}) {
            IkiWiki::rcs_remove($_);
        }
        else {
            IkiWiki::prune("$config{srcdir}/$_");
        }
    } @todelete;

    if (@todelete) {
        commit_and_refresh(
            gettext("removed obsolete PO files"),
            "IkiWiki::Plugin::po::deletetranslations");
    }
}

sub commit_and_refresh ($$) {
    my ($msg, $author) = (shift, shift);

    if ($config{rcs}) {
        IkiWiki::disable_commit_hook();
        IkiWiki::rcs_commit_staged($msg, $author, "127.0.0.1");
        IkiWiki::enable_commit_hook();
        IkiWiki::rcs_update();
    }
    # Reinitialize module's private variables.
    resetalreadyfiltered();
    resettranslationscache();
    flushmemoizecache();
    # Trigger a wiki refresh.
    require IkiWiki::Render;
    # without preliminary saveindex/loadindex, refresh()
    # complains about a lot of uninitialized variables
    IkiWiki::saveindex();
    IkiWiki::loadindex();
    IkiWiki::refresh();
    IkiWiki::saveindex();
}

# on success, returns the filtered content.
# on error, if $nonfatal, warn and return undef; else, error out.
sub po_to_markup ($$;$) {
    my ($page, $content) = (shift, shift);
    my $nonfatal = shift;

    $content = '' unless defined $content;
    $content = decode_utf8(encode_utf8($content));
    # CRLF line terminators make poor Locale::Po4a feel bad
    $content=~s/\r\n/\n/g;

    # There are incompatibilities between some File::Temp versions
    # (including 0.18, bundled with Lenny's perl-modules package)
    # and others (e.g. 0.20, previously present in the archive as
    # a standalone package): under certain circumstances, some
    # return a relative filename, whereas others return an absolute one;
    # we here use this module in a way that is at least compatible
    # with 0.18 and 0.20. Beware, hit'n'run refactorers!
    my $infile = new File::Temp(TEMPLATE => "ikiwiki-po-filter-in.XXXXXXXXXX",
                    DIR => File::Spec->tmpdir,
                    UNLINK => 1)->filename;
    my $outfile = new File::Temp(TEMPLATE => "ikiwiki-po-filter-out.XXXXXXXXXX",
                     DIR => File::Spec->tmpdir,
                     UNLINK => 1)->filename;

    my $fail = sub ($) {
        my $msg = "po(po_to_markup) - $page : " . shift;
        if ($nonfatal) {
            warn $msg;
            return undef;
        }
        error($msg, sub { unlink $infile, $outfile});
    };

    writefile(basename($infile), File::Spec->tmpdir, $content)
        or return $fail->(sprintf(gettext("failed to write %s"), $infile));

    my $masterfile = srcfile($pagesources{masterpage($page)});
    my %options = (
        "markdown" => (pagetype($masterfile) eq 'mdwn') ? 1 : 0,
    );
    my $doc=Locale::Po4a::Chooser::new('text',%options);
    $doc->process(
        'po_in_name'    => [ $infile ],
        'file_in_name'  => [ $masterfile ],
        'file_in_charset'  => 'utf-8',
        'file_out_charset' => 'utf-8',
    ) or return $fail->(gettext("failed to translate"));
    $doc->write($outfile)
        or return $fail->(sprintf(gettext("failed to write %s"), $outfile));

    $content = readfile($outfile)
        or return $fail->(sprintf(gettext("failed to read %s"), $outfile));

    # Unlinking should happen automatically, thanks to File::Temp,
    # but it does not work here, probably because of the way writefile()
    # and Locale::Po4a::write() work.
    unlink $infile, $outfile;

    return $content;
}

# returns a SuccessReason or FailReason object
sub isvalidpo ($) {
    my $content = shift;

    # NB: we don't use po_to_markup here, since Po4a parser does
    # not mind invalid PO content
    $content = '' unless defined $content;
    $content = decode_utf8(encode_utf8($content));

    # There are incompatibilities between some File::Temp versions
    # (including 0.18, bundled with Lenny's perl-modules package)
    # and others (e.g. 0.20, previously present in the archive as
    # a standalone package): under certain circumstances, some
    # return a relative filename, whereas others return an absolute one;
    # we here use this module in a way that is at least compatible
    # with 0.18 and 0.20. Beware, hit'n'run refactorers!
    my $infile = new File::Temp(TEMPLATE => "ikiwiki-po-isvalidpo.XXXXXXXXXX",
                    DIR => File::Spec->tmpdir,
                    UNLINK => 1)->filename;

    my $fail = sub ($) {
        my $msg = '[po/isvalidpo] ' . shift;
        unlink $infile;
        return IkiWiki::FailReason->new("$msg");
    };

    writefile(basename($infile), File::Spec->tmpdir, $content)
        or return $fail->(sprintf(gettext("failed to write %s"), $infile));

    my $res = (system("msgfmt", "--check", $infile, "-o", "/dev/null") == 0);

    # Unlinking should happen automatically, thanks to File::Temp,
    # but it does not work here, probably because of the way writefile()
    # and Locale::Po4a::write() work.
    unlink $infile;

    if ($res) {
        return IkiWiki::SuccessReason->new("valid gettext data");
    }
    return IkiWiki::FailReason->new("invalid gettext data, go back ".
                    "to previous page to go on with edit");
}

# ,----
# | PageSpecs
# `----

package IkiWiki::PageSpec;

sub match_istranslation ($;@) {
    my $page=shift;

    if (IkiWiki::Plugin::po::istranslation($page)) {
        return IkiWiki::SuccessReason->new("is a translation page");
    }
    else {
        return IkiWiki::FailReason->new("is not a translation page");
    }
}

sub match_istranslatable ($;@) {
    my $page=shift;

    if (IkiWiki::Plugin::po::istranslatable($page)) {
        return IkiWiki::SuccessReason->new("is set as translatable in po_translatable_pages");
    }
    else {
        return IkiWiki::FailReason->new("is not set as translatable in po_translatable_pages");
    }
}

sub match_lang ($$;@) {
    my $page=shift;
    my $wanted=shift;

    my $regexp=IkiWiki::glob2re($wanted);
    my $lang=IkiWiki::Plugin::po::lang($page);
    if ($lang !~ /^$regexp$/i) {
        return IkiWiki::FailReason->new("file language is $lang, not $wanted");
    }
    else {
        return IkiWiki::SuccessReason->new("file language is $wanted");
    }
}

sub match_currentlang ($$;@) {
    my $page=shift;
    shift;
    my %params=@_;

    return IkiWiki::FailReason->new("no location provided") unless exists $params{location};

    my $currentlang=IkiWiki::Plugin::po::lang($params{location});
    my $lang=IkiWiki::Plugin::po::lang($page);

    if ($lang eq $currentlang) {
        return IkiWiki::SuccessReason->new("file language is the same as current one, i.e. $currentlang");
    }
    else {
        return IkiWiki::FailReason->new("file language is $lang, whereas current language is $currentlang");
    }
}

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