ikiwiki/ todo/ darcs

Here's Thomas Schwinge unfinished darcs support for ikiwiki.

(Finishing this has been suggested as a soc project.)

I haven't been working on this for months and also won't in the near future. Feel free to use what I have done so far and bring it into an usable state! Also, feel free to contact me if there are questions.

-- Thomas Schwinge

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# Support for the darcs rcs, <URL:http://darcs.net/>.
# Copyright (C) 2006  Thomas Schwinge <tschwinge@gnu.org>
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.


# We're guaranteed to be the only instance of ikiwiki running at a given
# time.  It is essential that only ikiwiki is working on a particular
# repository.  That means one instance of ikiwiki and it also means that
# you must not `darcs push' into this repository, as this might create
# race conditions, as I understand it.


use warnings;
use strict;
use IkiWiki;

package IkiWiki;


# Which darcs executable to use.
my $darcs = ($ENV{DARCS} or 'darcs');


# Internal functions.

sub darcs_info ($$$) {
    my $field = shift;
    my $repodir = shift;
    my $file = shift; # Relative to the repodir.

    my $child = open(DARCS_CHANGES, "-|");
    if (! $child) {
    exec($darcs, 'changes', '--repo=' . $repodir, '--xml-output', $file) or
        error('failed to run `darcs changes\'');
    }

    # Brute force for now.  <img src="../smileys/ohwell.png" alt=":-/" />
    while (<DARCS_CHANGES>) {
    last if /^<\/created_as>$/;
    }
    ($_) = <DARCS_CHANGES> =~ /$field=\'([^\']+)/;
    $field eq 'hash' and s/\.gz//; # Strip away the `.gz' from `hash'es.

    close(DARCS_CHANGES) or error('`darcs changes\' exited ' . $?);

    return $_;
}


# Exported functions.

sub rcs_update () {
    # Not needed.
}

sub rcs_prepedit ($) {
    # Prepares to edit a file under revision control.  Returns a token that
    # must be passed to rcs_commit() when the file is to be commited.  For us,
    # this token the hash value of the latest patch that modifies the file,
    # i.e. something like its current revision.  If the file is not yet added
    # to the repository, we return TODO: the empty string.

    my $file = shift; # Relative to the repodir.

    my $hash = darcs_info('hash', $config{srcdir}, $file);
    return defined $hash ? $hash : "";
}

sub rcs_commit ($$$) {
    # Commit the page.  Returns `undef' on success and a version of the page
    # with conflict markers on failure.

    my $file = shift; # Relative to the repodir.
    my $message = shift;
    my $rcstoken = shift;

    # Compute if the ``revision'' of $file changed.
    my $changed = darcs_info('hash', $config{srcdir}, $file) ne $rcstoken;

    # Yes, the following is a bit convoluted.
    if ($changed) {
    # TODO.  Invent a better, non-conflicting name.
    rename("$config{srcdir}/$file", "$config{srcdir}/$file.save") or
        error("failed to rename $file to $file.save: $!");

    # Roll the repository back to $rcstoken.

    # TODO.  Can we be sure that no changes are lost?  I think that
    # we can, if we make sure that the `darcs push' below will always
    # succeed.

    # We need to revert everything as `darcs obliterate' might choke
    # otherwise.
        # TODO: `yes | ...' needed?  Doesn't seem so.
    system($darcs, "revert", "--repodir=" . $config{srcdir}, "--all") and
        error("`darcs revert' failed");
    # Remove all patches starting at $rcstoken.
    # TODO.  Something like `yes | darcs obliterate ...' seems to be needed.
    system($darcs, "obliterate", "--quiet", "--repodir" . $config{srcdir},
           "--match", "hash " . $rcstoken) and
           error("`darcs obliterate' failed");
    # Restore the $rcstoken one.
    system($darcs, "pull", "--quiet", "--repodir=" . $config{srcdir},
           "--match", "hash " . $rcstoken, "--all") and
           error("`darcs pull' failed");

    # We're back at $rcstoken.  Re-install the modified file.
    rename("$config{srcdir}/$file.save", "$config{srcdir}/$file") or
        error("failed to rename $file.save to $file: $!");
    }

    # Record the changes.
    # TODO: What if $message is empty?
    writefile("$file.log", $config{srcdir}, $message);
    system($darcs, 'record', '--repodir=' . $config{srcdir}, '--all',
       '--logfile=' . "$config{srcdir}/$file.log",
       '--author=' . 'web commit <web-hurd@gnu.org>', $file) and
           error('`darcs record\' failed');

    # Update the repository by pulling from the default repository, which is
    # master repository.
    system($darcs, "pull", "--quiet", "--repodir=" . $config{srcdir},
       "--all") and error("`darcs pull' failed\n");

    # If this updating yields any conflicts, we'll record them now to resolve
    # them.  If nothing is recorded, there are no conflicts.
    $rcstoken = darcs_info('hash', $config{srcdir}, $file);
    # TODO: Use only the first line here, i.e. only the patch name?
    writefile("$file.log", $config{srcdir}, 'resolve conflicts: ' . $message);
    system($darcs, 'record', '--repodir=' . $config{srcdir}, '--all',
       '--logfile=' . "$config{srcdir}/$file.log",
       '--author=' . 'web commit <web-hurd@gnu.org>', $file) and
           error('`darcs record\' failed');
    my $conflicts = darcs_info('hash', $config{srcdir}, $file) ne $rcstoken;
    unlink("$config{srcdir}/$file.log") or
    error("failed to remove `$file.log'");

    # Push the changes to the main repository.
    system($darcs, 'push', '--quiet', '--repodir=' . $config{srcdir}, '--all')
    and error('`darcs push\' failed');
    # TODO: darcs send?

    if ($conflicts) {
    my $document = readfile("$config{srcdir}/$file");
    # Try to leave everything in a consistent state.
        # TODO: `yes | ...' needed?  Doesn't seem so.
    system($darcs, "revert", "--repodir=" . $config{srcdir}, "--all") and
        warn("`darcs revert' failed.\n");
    return $document;
    } else {
    return undef;
    }
}

sub rcs_add ($) {
    my $file = shift; # Relative to the repodir.

    # Intermediate directories will be added automagically.
    system($darcs, 'add', '--quiet', '--repodir=' . $config{srcdir},
       '--boring', $file) and error('`darcs add\' failed');
}

sub rcs_recentchanges ($) {
    warn('rcs_recentchanges() is not implemented');
    return 'rcs_recentchanges() is not implemented';
}

sub rcs_notify () {
    warn('rcs_notify() is not implemented');
}

sub rcs_getctime () {
    warn('rcs_getctime() is not implemented');
}

1

This is my (bma) darcs.pm - it's messy (my Perl isn't up to much) but seems to work. It uses just one repo, like the mercurial plugin (unlike the above version, which AIUI uses two).

rcs_commit() uses backticks instead of system(), to prevent darcs' output being sent to the browser and mucking with the HTTP headers (darcs record has no --quiet option). And rcs_recentchanges() uses regexes rather than parsing darcs' XML output.

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#!/usr/bin/perl

use warnings;
use strict;
use IkiWiki;
use Date::Parse;
use open qw{:utf8 :std};

package IkiWiki;

sub rcs_update () { #{{{
    # Do nothing - there's nowhere to update *from*.
} #}}}

sub rcs_prepedit ($) { #{{{
} #}}}

sub rcs_commit ($$$;$$) { #{{{
    my ($file, $message, $rcstoken, $user, $ipaddr) = @_;

    # $user should probably be a name and an email address, by darcs
    # convention.
    if (defined $user) {
        $user = possibly_foolish_untaint($user);
    }
    elsif (defined $ipaddr) {
        $user = "Anonymous from $ipaddr";
    }
    else {
        $user = "Anonymous";
    }

    $message = possibly_foolish_untaint($message);

    # BUG: this outputs one line of text, and there's not a -q or --quiet
    # option. Redirecting output to /dev/null works, but I still get the
    # HTTP status and location headers displayed in the browser - is that
    # darcs' fault or ikiwiki's?
    # Doing it in backticks *works*, but I'm sure it could be done better.
    my @cmdline = ("darcs", "record", "--repodir", "$config{srcdir}",
                   "-a", "-m", "$message", "--author", "$user", $file);
    `darcs record --repodir "$config{srcdir}" -a -m "$message" --author "$user" $file`; # Return value? Output? Who needs 'em?
    #if (system(@cmdline) != 0) {
    #   warn "'@cmdline' failed: $!";
    #}

    return undef; # success

sub rcs_add ($) { # {{{
    my ($file) = @_;

    my @cmdline = ("darcs", "add", "--repodir", "$config{srcdir}", "-a", "-q", "$file");
    if (system(@cmdline) != 0) {
        warn "'@cmdline' failed: $!";
    }
} #}}}

sub rcs_recentchanges ($) { #{{{
    # TODO: This is horrible code. It doesn't work perfectly, and uses regexes
    # rather than parsing Darcs' XML output.
    my $num=shift;
    my @ret;

    return unless -d "$config{srcdir}/_darcs";

    my $changelog = `darcs changes --xml --summary --repodir "$config{srcdir}"`;
    $changelog = join("", split(/\s*\n\s*/, $changelog));
    my @changes = split(/<\/patch>.*?<patch/m, $changelog);


    foreach my $change (@changes) {
        $change =~ m/hash='(.*?)'/;
        my $rev = $1;
        $change =~ m/author='(.*?)'/;
        my $user = $1."\n";
        my $committype = "web";
        if($user =~ m/&lt;/) {
            # Author fields generated by darcs include an email address: look for the "<".
            $committype = "darcs";
            use HTML::Entities;
            $user = decode_entities $user;
        }
        $change =~ m/local_date='(.*?)'/;
        my $when = $1;
        $when=time - str2time($when, 'UTC');
        $change =~ m/<name>(.*?)<\/name>/g;
        my @message = {line => $1};
        foreach my $match ($change =~ m/<comment>(.*?)<\/comment>/gm) {
            push @message, {line => $1};
        }

        my @pages;
        foreach my $match ($change =~ m/<.*?_(file|directory)>(.*?)(<(added|removed)_lines.*\/>)*<\/.*?_(file|directory)>/g) {
            # My perl-fu is weak. I'm probably going about this all wrong, anyway.
            push @pages, {page => pagename($match)} if ( -f $config{srcdir}."/".$match || -d $config{srcdir}."/".$match) and not $match =~ m/^$/;
        }
        push @ret, { rev => $rev,
                user => $user,
                committype => $committype,
                when => $when,
                message => [@message],
                pages => [@pages],
            }
    }
    return @ret;
} #}}}

sub rcs_notify () { #{{{
    # TODO
} #}}}

sub rcs_getctime ($) { #{{{
    error gettext("getctime not implemented");
} #}}}

1

Well, here's my version too. It only does getctime -- using a real XML parser, instead of regexp ugliness -- and maybe recentchanges, but that may be bitrotted, or maybe I never finished it, as I only need the getctime. As for actual commits, I have previously voiced my opinion, that this should be done by the plugin generating a patch bundle, and forwarding it to darcs in some way (darcs apply or even email to another host, possibly moderated), instead of the hacky direct modification of a working copy. It could also be faster to getctime in a batch. Just reading in all the changes the first time they're needed, might not be a big improvement in many cases, but if we got a batch request from ikiwiki, we could keep reaing the changes until all the files in this batch request have been met. --tuomov

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#!/usr/bin/perl
# Stubs for no revision control.

use warnings;
use strict;
use IkiWiki;

package IkiWiki;

sub rcs_update () {
}

sub rcs_prepedit ($) {
    return ""
}

sub rcs_commit ($$$) {
    return undef # success
}

sub rcs_add ($) {
}

sub rcs_recentchanges ($) {
    my $num=shift;
    my @ret;

    eval q{use Date::Parse};
    eval q{use XML::Simple};

    my $repodir=$config{srcdir};

    if (-d "$config{srcdir}/_darcs") {
        my $child = open(LOG, "-|");
        if (! $child) {
            exec("darcs", "changes", "--xml", 
                 "--repodir", "$repodir",
                 "--last", "$num")
            || error("darcs changes failed to run");
        }
        my $data=;
        close LOG;

        my $log = XMLin($data, ForceArray => 1);

        foreach my $patch ($log->{patch}) {
            my $date=$patch->{local_date};
            my $hash=$patch->{hash};
            my $when=concise(ago(time - str2time($date)));
            my @pages;

            my $child = open(SUMMARY, "-|");
            if (! $child) {
                exec("darcs", "annotate", "-s", "--xml", 
                     "--match", "hash: $hash",
                     "--repodir", "$repodir")
                || error("darcs annotate failed to run");
            }
            my $data=;
            close SUMMARY;

            my $summary = XMLin("$data", ForceArray => 1);

            # TODO: find @pages

            push @ret, {
                #rev => $rev,
                user => $patch->{author},
                #committype => $committype,
                when => $when, 
                #message => [@message],
                pages => [@pages],
            }; # if @pages;
            return @ret if @ret >= $num;
        }
    }

    return @ret;
}

sub rcs_notify () {
}

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

    eval q{use Date::Parse};
    eval q{use XML::Simple};
    local $/=undef;

    # Sigh... doing things the hard way again
    my $repodir=$config{srcdir};

    my $filer=substr($file, length($repodir));
    $filer =~ s:^[/]+::;

    my $child = open(LOG, "-|");
    if (! $child) {
        exec("darcs", "changes", "--xml", "--reverse",
             "--repodir", "$repodir", "$filer")
        || error("darcs changes $filer failed to run");
    }

    my $data=;
    close LOG;

    my $log = XMLin($data, ForceArray => 1);

    my $datestr=$log->{patch}[0]->{local_date};

    if (! defined $datestr) {
        warn "failed to get ctime for $filer";
        return 0;
    }

    my $date=str2time($datestr);

    debug("found ctime ".localtime($date)." for $file");

    return $date;
}

1