path: root/IkiWiki/Plugin/highlight.pm

#!/usr/bin/perl
package IkiWiki::Plugin::highlight;

use warnings;
use strict;
use IkiWiki 3.00;
use Encode;

sub import {
    hook(type => "getsetup", id => "highlight",  call => \&getsetup);
    hook(type => "checkconfig", id => "highlight", call => \&checkconfig);
    # this hook is used by the format plugin
    hook(type => "htmlizefallback", id => "highlight", call =>
        \&htmlizefallback);
}

sub getsetup () {
    return
        plugin => {
            safe => 1,
            rebuild => 1, # format plugin
            section => "format",
        },
        tohighlight => {
            type => "string",
            example => ".c .h .cpp .pl .py Makefile:make",
            description => "types of source files to syntax highlight",
            safe => 1,
            rebuild => 1,
        },
        filetypes_conf => {
            type => "string",
            example => "/etc/highlight/filetypes.conf",
            description => "location of highlight's filetypes.conf",
            safe => 0,
            rebuild => undef,
        },
        langdefdir => {
            type => "string",
            example => "/usr/share/highlight/langDefs",
            description => "location of highlight's langDefs directory",
            safe => 0,
            rebuild => undef,
        },
}

sub checkconfig () {
    if (! exists $config{filetypes_conf}) {
        $config{filetypes_conf}="/etc/highlight/filetypes.conf";
    }
    if (! exists $config{langdefdir}) {
        $config{langdefdir}="/usr/share/highlight/langDefs";
    }
    if (exists $config{tohighlight}) {
        foreach my $file (split ' ', $config{tohighlight}) {
            my @opts = $file=~s/^\.// ?
                (keepextension => 1) :
                (noextension => 1);
            my $ext = $file=~s/:(.*)// ? $1 : $file;
        
            my $langfile=ext2langfile($ext);
            if (! defined $langfile) {
                error(sprintf(gettext(
                    "tohighlight contains unknown file type '%s'"),
                    $ext));
            }
    
            hook(
                type => "htmlize",
                id => $file,
                call => sub {
                    my %params=@_;
                        highlight($langfile, $params{content});
                },
                longname => sprintf(gettext("Source code: %s"), $file),
                @opts,
            );
        }
    }
}

sub htmlizefallback {
    my $format=lc shift;
    my $langfile=ext2langfile($format);

    if (! defined $langfile) {
        return;
    }

    return Encode::decode_utf8(highlight($langfile, shift));
}

my %ext2lang;
my $filetypes_read=0;
my %highlighters;

# Parse highlight's config file to get extension => language mappings.
sub read_filetypes () {
    open (IN, $config{filetypes_conf}) || error("$config{filetypes_conf}: $!");
    while (<IN>) {
        chomp;
        if (/^\$ext\((.*)\)=(.*)$/) {
            $ext2lang{$_}=$1 foreach $1, split ' ', $2;
        }
    }
    close IN;
    $filetypes_read=1;
}


# Given a filename extension, determines the language definition to
# use to highlight it.
sub ext2langfile ($) {
    my $ext=shift;

    my $langfile="$config{langdefdir}/$ext.lang";
    return $langfile if exists $highlighters{$langfile};

    read_filetypes() unless $filetypes_read;
    if (exists $ext2lang{$ext}) {
        return "$config{langdefdir}/$ext2lang{$ext}.lang";
    }
    # If a language only has one common extension, it will not
    # be listed in filetypes, so check the langfile.
    elsif (-e $langfile) {
        return $langfile;
    }
    else {
        return undef;
    }
}

# Interface to the highlight C library.
sub highlight ($$) {
    my $langfile=shift;
    my $input=shift;

    eval q{use highlight};
    if ($@) {
        print STDERR gettext("warning: highlight perl module not available; falling back to pass through");
        return $input;
    }

    my $gen;
    if (! exists $highlighters{$langfile}) {
        $gen = highlightc::CodeGenerator_getInstance($highlightc::XHTML);
        $gen->setFragmentCode(1); # generate html fragment
        $gen->setHTMLEnclosePreTag(1); # include stylish <pre>
        $gen->initTheme("/dev/null"); # theme is not needed because CSS is not emitted
        $gen->initLanguage($langfile); # must come after initTheme
        $gen->setEncoding("utf-8");
        $highlighters{$langfile}=$gen;
    }
    else {      
        $gen=$highlighters{$langfile};
    }

    return $gen->generateString($input);
}

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