#!/usr/bin/env perl
# Copyright (C) 2006, Eric Wong <normalperson@yhbt.net>
# License: GPL v2 or later
use warnings;
use strict;
use vars qw/    $AUTHOR $VERSION
                $SVN_URL $SVN_INFO $SVN_WC $SVN_UUID
                $GIT_SVN_INDEX $GIT_SVN
                $GIT_DIR $REV_DIR $GIT_SVN_DIR/;
$AUTHOR = 'Eric Wong <normalperson@yhbt.net>';
$VERSION = '1.1.0-pre';

use Cwd qw/abs_path/;
$GIT_DIR = abs_path($ENV{GIT_DIR} || '.git');
$ENV{GIT_DIR} = $GIT_DIR;

my $LC_ALL = $ENV{LC_ALL};
my $TZ = $ENV{TZ};
# make sure the svn binary gives consistent output between locales and TZs:
$ENV{TZ} = 'UTC';
$ENV{LC_ALL} = 'C';

# If SVN:: library support is added, please make the dependencies
# optional and preserve the capability to use the command-line client.
# use eval { require SVN::... } to make it lazy load
# We don't use any modules not in the standard Perl distribution:
use Carp qw/croak/;
use IO::File qw//;
use File::Basename qw/dirname basename/;
use File::Path qw/mkpath/;
use Getopt::Long qw/:config gnu_getopt no_ignore_case auto_abbrev pass_through/;
use File::Spec qw//;
use POSIX qw/strftime/;
my $sha1 = qr/[a-f\d]{40}/;
my $sha1_short = qr/[a-f\d]{4,40}/;
my ($_revision,$_stdin,$_no_ignore_ext,$_no_stop_copy,$_help,$_rmdir,$_edit,
        $_find_copies_harder, $_l, $_cp_similarity,
        $_repack, $_repack_nr, $_repack_flags,
        $_template, $_shared, $_no_default_regex, $_no_graft_copy,
        $_limit, $_verbose, $_incremental, $_oneline, $_l_fmt, $_show_commit,
        $_version, $_upgrade, $_authors, $_branch_all_refs, @_opt_m);
my (@_branch_from, %tree_map, %users, %rusers);
my ($_svn_co_url_revs, $_svn_pg_peg_revs);
my @repo_path_split_cache;

my %fc_opts = ( 'no-ignore-externals' => \$_no_ignore_ext,
                'branch|b=s' => \@_branch_from,
                'branch-all-refs|B' => \$_branch_all_refs,
                'authors-file|A=s' => \$_authors,
                'repack:i' => \$_repack,
                'repack-flags|repack-args|repack-opts=s' => \$_repack_flags);

my ($_trunk, $_tags, $_branches);
my %multi_opts = ( 'trunk|T=s' => \$_trunk,
                'tags|t=s' => \$_tags,
                'branches|b=s' => \$_branches );
my %init_opts = ( 'template=s' => \$_template, 'shared' => \$_shared );

# yes, 'native' sets "\n".  Patches to fix this for non-*nix systems welcome:
my %EOL = ( CR => "\015", LF => "\012", CRLF => "\015\012", native => "\012" );

my %cmd = (
        fetch => [ \&fetch, "Download new revisions from SVN",
                        { 'revision|r=s' => \$_revision, %fc_opts } ],
        init => [ \&init, "Initialize a repo for tracking" .
                          " (requires URL argument)",
                          \%init_opts ],
        commit => [ \&commit, "Commit git revisions to SVN",
                        {       'stdin|' => \$_stdin,
                                'edit|e' => \$_edit,
                                'rmdir' => \$_rmdir,
                                'find-copies-harder' => \$_find_copies_harder,
                                'l=i' => \$_l,
                                'copy-similarity|C=i'=> \$_cp_similarity,
                                %fc_opts,
                        } ],
        'show-ignore' => [ \&show_ignore, "Show svn:ignore listings", { } ],
        rebuild => [ \&rebuild, "Rebuild git-svn metadata (after git clone)",
                        { 'no-ignore-externals' => \$_no_ignore_ext,
                          'upgrade' => \$_upgrade } ],
        'graft-branches' => [ \&graft_branches,
                        'Detect merges/branches from already imported history',
                        { 'merge-rx|m' => \@_opt_m,
                          'no-default-regex' => \$_no_default_regex,
                          'no-graft-copy' => \$_no_graft_copy } ],
        'multi-init' => [ \&multi_init,
                        'Initialize multiple trees (like git-svnimport)',
                        { %multi_opts, %fc_opts } ],
        'multi-fetch' => [ \&multi_fetch,
                        'Fetch multiple trees (like git-svnimport)',
                        \%fc_opts ],
        'log' => [ \&show_log, 'Show commit logs',
                        { 'limit=i' => \$_limit,
                          'revision|r=s' => \$_revision,
                          'verbose|v' => \$_verbose,
                          'incremental' => \$_incremental,
                          'oneline' => \$_oneline,
                          'show-commit' => \$_show_commit,
                          'authors-file|A=s' => \$_authors,
                        } ],
);

my $cmd;
for (my $i = 0; $i < @ARGV; $i++) {
        if (defined $cmd{$ARGV[$i]}) {
                $cmd = $ARGV[$i];
                splice @ARGV, $i, 1;
                last;
        }
};

my %opts = %{$cmd{$cmd}->[2]} if (defined $cmd);

read_repo_config(\%opts);
my $rv = GetOptions(%opts, 'help|H|h' => \$_help,
                                'version|V' => \$_version,
                                'id|i=s' => \$GIT_SVN);
exit 1 if (!$rv && $cmd ne 'log');

set_default_vals();
usage(0) if $_help;
version() if $_version;
usage(1) unless defined $cmd;
init_vars();
load_authors() if $_authors;
load_all_refs() if $_branch_all_refs;
svn_compat_check();
migration_check() unless $cmd =~ /^(?:init|multi-init)$/;
$cmd{$cmd}->[0]->(@ARGV);
exit 0;

####################### primary functions ######################
sub usage {
        my $exit = shift || 0;
        my $fd = $exit ? \*STDERR : \*STDOUT;
        print $fd <<"";
git-svn - bidirectional operations between a single Subversion tree and git
Usage: $0 <command> [options] [arguments]\n

        print $fd "Available commands:\n" unless $cmd;

        foreach (sort keys %cmd) {
                next if $cmd && $cmd ne $_;
                print $fd '  ',pack('A13',$_),$cmd{$_}->[1],"\n";
                foreach (keys %{$cmd{$_}->[2]}) {
                        # prints out arguments as they should be passed:
                        my $x = s#[:=]s$## ? '<arg>' : s#[:=]i$## ? '<num>' : '';
                        print $fd ' ' x 17, join(', ', map { length $_ > 1 ?
                                                        "--$_" : "-$_" }
                                                split /\|/,$_)," $x\n";
                }
        }
        print $fd <<"";
\nGIT_SVN_ID may be set in the environment or via the --id/-i switch to an
arbitrary identifier if you're tracking multiple SVN branches/repositories in
one git repository and want to keep them separate.  See git-svn(1) for more
information.

        exit $exit;
}

sub version {
        print "git-svn version $VERSION\n";
        exit 0;
}

sub rebuild {
        $SVN_URL = shift or undef;
        my $newest_rev = 0;
        if ($_upgrade) {
                sys('git-update-ref',"refs/remotes/$GIT_SVN","$GIT_SVN-HEAD");
        } else {
                check_upgrade_needed();
        }

        my $pid = open(my $rev_list,'-|');
        defined $pid or croak $!;
        if ($pid == 0) {
                exec("git-rev-list","refs/remotes/$GIT_SVN") or croak $!;
        }
        my $latest;
        while (<$rev_list>) {
                chomp;
                my $c = $_;
                croak "Non-SHA1: $c\n" unless $c =~ /^$sha1$/o;
                my @commit = grep(/^git-svn-id: /,`git-cat-file commit $c`);
                next if (!@commit); # skip merges
                my ($url, $rev, $uuid) = extract_metadata($commit[$#commit]);
                if (!$rev || !$uuid) {
                        croak "Unable to extract revision or UUID from ",
                                "$c, $commit[$#commit]\n";
                }

                # if we merged or otherwise started elsewhere, this is
                # how we break out of it
                next if (defined $SVN_UUID && ($uuid ne $SVN_UUID));
                next if (defined $SVN_URL && defined $url && ($url ne $SVN_URL));

                print "r$rev = $c\n";
                unless (defined $latest) {
                        if (!$SVN_URL && !$url) {
                                croak "SVN repository location required: $url\n";
                        }
                        $SVN_URL ||= $url;
                        $SVN_UUID ||= $uuid;
                        setup_git_svn();
                        $latest = $rev;
                }
                assert_revision_eq_or_unknown($rev, $c);
                sys('git-update-ref',"svn/$GIT_SVN/revs/$rev",$c);
                $newest_rev = $rev if ($rev > $newest_rev);
        }
        close $rev_list or croak $?;
        if (!chdir $SVN_WC) {
                svn_cmd_checkout($SVN_URL, $latest, $SVN_WC);
                chdir $SVN_WC or croak $!;
        }

        $pid = fork;
        defined $pid or croak $!;
        if ($pid == 0) {
                my @svn_up = qw(svn up);
                push @svn_up, '--ignore-externals' unless $_no_ignore_ext;
                sys(@svn_up,"-r$newest_rev");
                $ENV{GIT_INDEX_FILE} = $GIT_SVN_INDEX;
                index_changes();
                exec('git-write-tree') or croak $!;
        }
        waitpid $pid, 0;
        croak $? if $?;

        if ($_upgrade) {
                print STDERR <<"";
Keeping deprecated refs/head/$GIT_SVN-HEAD for now.  Please remove it
when you have upgraded your tools and habits to use refs/remotes/$GIT_SVN

        }
}

sub init {
        $SVN_URL = shift or die "SVN repository location required " .
                                "as a command-line argument\n";
        $SVN_URL =~ s!/+$!!; # strip trailing slash
        unless (-d $GIT_DIR) {
                my @init_db = ('git-init-db');
                push @init_db, "--template=$_template" if defined $_template;
                push @init_db, "--shared" if defined $_shared;
                sys(@init_db);
        }
        setup_git_svn();
}

sub fetch {
        my (@parents) = @_;
        check_upgrade_needed();
        $SVN_URL ||= file_to_s("$GIT_SVN_DIR/info/url");
        my @log_args = -d $SVN_WC ? ($SVN_WC) : ($SVN_URL);
        unless ($_revision) {
                $_revision = -d $SVN_WC ? 'BASE:HEAD' : '0:HEAD';
        }
        push @log_args, "-r$_revision";
        push @log_args, '--stop-on-copy' unless $_no_stop_copy;

        my $svn_log = svn_log_raw(@log_args);

        my $base = next_log_entry($svn_log) or croak "No base revision!\n";
        my $last_commit = undef;
        unless (-d $SVN_WC) {
                svn_cmd_checkout($SVN_URL,$base->{revision},$SVN_WC);
                chdir $SVN_WC or croak $!;
                read_uuid();
                $last_commit = git_commit($base, @parents);
                assert_tree($last_commit);
        } else {
                chdir $SVN_WC or croak $!;
                read_uuid();
                eval { $last_commit = file_to_s("$REV_DIR/$base->{revision}") };
                # looks like a user manually cp'd and svn switch'ed
                unless ($last_commit) {
                        sys(qw/svn revert -R ./);
                        assert_svn_wc_clean($base->{revision});
                        $last_commit = git_commit($base, @parents);
                        assert_tree($last_commit);
                }
        }
        my @svn_up = qw(svn up);
        push @svn_up, '--ignore-externals' unless $_no_ignore_ext;
        my $last = $base;
        while (my $log_msg = next_log_entry($svn_log)) {
                assert_tree($last_commit);
                if ($last->{revision} >= $log_msg->{revision}) {
                        croak "Out of order: last >= current: ",
                                "$last->{revision} >= $log_msg->{revision}\n";
                }
                # Revert is needed for cases like:
                # https://svn.musicpd.org/Jamming/trunk (r166:167), but
                # I can't seem to reproduce something like that on a test...
                sys(qw/svn revert -R ./);
                assert_svn_wc_clean($last->{revision});
                sys(@svn_up,"-r$log_msg->{revision}");
                $last_commit = git_commit($log_msg, $last_commit, @parents);
                $last = $log_msg;
        }
        unless (-e "$GIT_DIR/refs/heads/master") {
                sys(qw(git-update-ref refs/heads/master),$last_commit);
        }
        close $svn_log->{fh};
        return $last;
}

sub commit {
        my (@commits) = @_;
        check_upgrade_needed();
        if ($_stdin || !@commits) {
                print "Reading from stdin...\n";
                @commits = ();
                while (<STDIN>) {
                        if (/\b($sha1_short)\b/o) {
                                unshift @commits, $1;
                        }
                }
        }
        my @revs;
        foreach my $c (@commits) {
                chomp(my @tmp = safe_qx('git-rev-parse',$c));
                if (scalar @tmp == 1) {
                        push @revs, $tmp[0];
                } elsif (scalar @tmp > 1) {
                        push @revs, reverse (safe_qx('git-rev-list',@tmp));
                } else {
                        die "Failed to rev-parse $c\n";
                }
        }
        chomp @revs;

        chdir $SVN_WC or croak "Unable to chdir $SVN_WC: $!\n";
        my $info = svn_info('.');
        my $fetched = fetch();
        if ($info->{Revision} != $fetched->{revision}) {
                print STDERR "There are new revisions that were fetched ",
                                "and need to be merged (or acknowledged) ",
                                "before committing.\n";
                exit 1;
        }
        $info = svn_info('.');
        read_uuid($info);
        my $svn_current_rev =  $info->{'Last Changed Rev'};
        foreach my $c (@revs) {
                my $mods = svn_checkout_tree($svn_current_rev, $c);
                if (scalar @$mods == 0) {
                        print "Skipping, no changes detected\n";
                        next;
                }
                $svn_current_rev = svn_commit_tree($svn_current_rev, $c);
        }
        print "Done committing ",scalar @revs," revisions to SVN\n";
}

sub show_ignore {
        require File::Find or die $!;
        my $exclude_file = "$GIT_DIR/info/exclude";
        open my $fh, '<', $exclude_file or croak $!;
        chomp(my @excludes = (<$fh>));
        close $fh or croak $!;

        $SVN_URL ||= file_to_s("$GIT_SVN_DIR/info/url");
        chdir $SVN_WC or croak $!;
        my %ign;
        File::Find::find({wanted=>sub{if(lstat $_ && -d _ && -d "$_/.svn"){
                s#^\./##;
                @{$ign{$_}} = svn_propget_base('svn:ignore', $_);
                }}, no_chdir=>1},'.');

        print "\n# /\n";
        foreach (@{$ign{'.'}}) { print '/',$_ if /\S/ }
        delete $ign{'.'};
        foreach my $i (sort keys %ign) {
                print "\n# ",$i,"\n";
                foreach (@{$ign{$i}}) { print '/',$i,'/',$_ if /\S/ }
        }
}

sub graft_branches {
        my $gr_file = "$GIT_DIR/info/grafts";
        my ($grafts, $comments) = read_grafts($gr_file);
        my $gr_sha1;

        if (%$grafts) {
                # temporarily disable our grafts file to make this idempotent
                chomp($gr_sha1 = safe_qx(qw/git-hash-object -w/,$gr_file));
                rename $gr_file, "$gr_file~$gr_sha1" or croak $!;
        }

        my $l_map = read_url_paths();
        my @re = map { qr/$_/is } @_opt_m if @_opt_m;
        unless ($_no_default_regex) {
                push @re, (     qr/\b(?:merge|merging|merged)\s+(\S.+)/is,
                                qr/\b(?:from|of)\s+(\S.+)/is );
        }
        foreach my $u (keys %$l_map) {
                if (@re) {
                        foreach my $p (keys %{$l_map->{$u}}) {
                                graft_merge_msg($grafts,$l_map,$u,$p);
                        }
                }
                graft_file_copy($grafts,$l_map,$u) unless $_no_graft_copy;
        }

        write_grafts($grafts, $comments, $gr_file);
        unlink "$gr_file~$gr_sha1" if $gr_sha1;
}

sub multi_init {
        my $url = shift;
        $_trunk ||= 'trunk';
        $_trunk =~ s#/+$##;
        $url =~ s#/+$## if $url;
        if ($_trunk !~ m#^[a-z\+]+://#) {
                $_trunk = '/' . $_trunk if ($_trunk !~ m#^/#);
                unless ($url) {
                        print STDERR "E: '$_trunk' is not a complete URL ",
                                "and a separate URL is not specified\n";
                        exit 1;
                }
                $_trunk = $url . $_trunk;
        }
        if ($GIT_SVN eq 'git-svn') {
                print "GIT_SVN_ID set to 'trunk' for $_trunk\n";
                $GIT_SVN = $ENV{GIT_SVN_ID} = 'trunk';
        }
        init_vars();
        init($_trunk);
        complete_url_ls_init($url, $_branches, '--branches/-b', '');
        complete_url_ls_init($url, $_tags, '--tags/-t', 'tags/');
}

sub multi_fetch {
        # try to do trunk first, since branches/tags
        # may be descended from it.
        if (-d "$GIT_DIR/svn/trunk") {
                print "Fetching trunk\n";
                defined(my $pid = fork) or croak $!;
                if (!$pid) {
                        $GIT_SVN = $ENV{GIT_SVN_ID} = 'trunk';
                        init_vars();
                        fetch(@_);
                        exit 0;
                }
                waitpid $pid, 0;
                croak $? if $?;
        }
        rec_fetch('', "$GIT_DIR/svn", @_);
}

sub show_log {
        my (@args) = @_;
        my ($r_min, $r_max);
        my $r_last = -1; # prevent dupes
        rload_authors() if $_authors;
        if (defined $TZ) {
                $ENV{TZ} = $TZ;
        } else {
                delete $ENV{TZ};
        }
        if (defined $_revision) {
                if ($_revision =~ /^(\d+):(\d+)$/) {
                        ($r_min, $r_max) = ($1, $2);
                } elsif ($_revision =~ /^\d+$/) {
                        $r_min = $r_max = $_revision;
                } else {
                        print STDERR "-r$_revision is not supported, use ",
                                "standard \'git log\' arguments instead\n";
                        exit 1;
                }
        }

        my $pid = open(my $log,'-|');
        defined $pid or croak $!;
        if (!$pid) {
                my @rl = (qw/git-log --abbrev-commit --pretty=raw
                                --default/, "remotes/$GIT_SVN");
                push @rl, '--raw' if $_verbose;
                exec(@rl, @args) or croak $!;
        }
        setup_pager();
        my (@k, $c, $d);
        while (<$log>) {
                if (/^commit ($sha1_short)/o) {
                        my $cmt = $1;
                        if ($c && defined $c->{r} && $c->{r} != $r_last) {
                                $r_last = $c->{r};
                                process_commit($c, $r_min, $r_max, \@k) or
                                                                goto out;
                        }
                        $d = undef;
                        $c = { c => $cmt };
                } elsif (/^author (.+) (\d+) ([\-\+]?\d+)$/) {
                        get_author_info($c, $1, $2, $3);
                } elsif (/^(?:tree|parent|committer) /) {
                        # ignore
                } elsif (/^:\d{6} \d{6} $sha1_short/o) {
                        push @{$c->{raw}}, $_;
                } elsif (/^diff /) {
                        $d = 1;
                        push @{$c->{diff}}, $_;
                } elsif ($d) {
                        push @{$c->{diff}}, $_;
                } elsif (/^    (git-svn-id:.+)$/) {
                        my ($url, $rev, $uuid) = extract_metadata($1);
                        $c->{r} = $rev;
                } elsif (s/^    //) {
                        push @{$c->{l}}, $_;
                }
        }
        if ($c && defined $c->{r} && $c->{r} != $r_last) {
                $r_last = $c->{r};
                process_commit($c, $r_min, $r_max, \@k);
        }
        if (@k) {
                my $swap = $r_max;
                $r_max = $r_min;
                $r_min = $swap;
                process_commit($_, $r_min, $r_max) foreach reverse @k;
        }
out:
        close $log;
        print '-' x72,"\n" unless $_incremental || $_oneline;
}

########################### utility functions #########################

sub rec_fetch {
        my ($pfx, $p, @args) = @_;
        my @dir;
        foreach (sort <$p/*>) {
                if (-r "$_/info/url") {
                        $pfx .= '/' if $pfx && $pfx !~ m!/$!;
                        my $id = $pfx . basename $_;
                        next if $id eq 'trunk';
                        print "Fetching $id\n";
                        defined(my $pid = fork) or croak $!;
                        if (!$pid) {
                                $GIT_SVN = $ENV{GIT_SVN_ID} = $id;
                                init_vars();
                                fetch(@args);
                                exit 0;
                        }
                        waitpid $pid, 0;
                        croak $? if $?;
                } elsif (-d $_) {
                        push @dir, $_;
                }
        }
        foreach (@dir) {
                my $x = $_;
                $x =~ s!^\Q$GIT_DIR\E/svn/!!;
                rec_fetch($x, $_);
        }
}

sub complete_url_ls_init {
        my ($url, $var, $switch, $pfx) = @_;
        unless ($var) {
                print STDERR "W: $switch not specified\n";
                return;
        }
        $var =~ s#/+$##;
        if ($var !~ m#^[a-z\+]+://#) {
                $var = '/' . $var if ($var !~ m#^/#);
                unless ($url) {
                        print STDERR "E: '$var' is not a complete URL ",
                                "and a separate URL is not specified\n";
                        exit 1;
                }
                $var = $url . $var;
        }
        chomp(my @ls = safe_qx(qw/svn ls --non-interactive/, $var));
        my $old = $GIT_SVN;
        defined(my $pid = fork) or croak $!;
        if (!$pid) {
                foreach my $u (map { "$var/$_" } (grep m!/$!, @ls)) {
                        $u =~ s#/+$##;
                        if ($u !~ m!\Q$var\E/(.+)$!) {
                                print STDERR "W: Unrecognized URL: $u\n";
                                die "This should never happen\n";
                        }
                        my $id = $pfx.$1;
                        print "init $u => $id\n";
                        $GIT_SVN = $ENV{GIT_SVN_ID} = $id;
                        init_vars();
                        init($u);
                }
                exit 0;
        }
        waitpid $pid, 0;
        croak $? if $?;
}

sub common_prefix {
        my $paths = shift;
        my %common;
        foreach (@$paths) {
                my @tmp = split m#/#, $_;
                my $p = '';
                while (my $x = shift @tmp) {
                        $p .= "/$x";
                        $common{$p} ||= 0;
                        $common{$p}++;
                }
        }
        foreach (sort {length $b <=> length $a} keys %common) {
                if ($common{$_} == @$paths) {
                        return $_;
                }
        }
        return '';
}

# this isn't funky-filename safe, but good enough for now...
sub graft_file_copy {
        my ($grafts, $l_map, $u) = @_;
        my $paths = $l_map->{$u};
        my $pfx = common_prefix([keys %$paths]);

        my $pid = open my $fh, '-|';
        defined $pid or croak $!;
        unless ($pid) {
                exec(qw/svn log -v/, $u.$pfx) or croak $!;
        }
        my ($r, $mp) = (undef, undef);
        while (<$fh>) {
                chomp;
                if (/^\-{72}$/) {
                        $mp = $r = undef;
                } elsif (/^r(\d+) \| /) {
                        $r = $1 unless defined $r;
                } elsif (/^Changed paths:/) {
                        $mp = 1;
                } elsif ($mp && m#^   [AR] /(\S.*?) \(from /(\S+?):(\d+)\)$#) {
                        my $dbg = "r$r | $_";
                        my ($p1, $p0, $r0) = ($1, $2, $3);
                        my $c;
                        foreach my $x (keys %$paths) {
                                next unless ($p1 =~ /^\Q$x\E/);
                                my $i = $paths->{$x};
                                my $f = "$GIT_DIR/svn/$i/revs/$r";
                                unless (-r $f) {
                                        print STDERR "r$r of $i not imported,",
                                                                " $dbg\n";
                                        next;
                                }
                                $c = file_to_s($f);
                        }
                        next unless $c;
                        foreach my $x (keys %$paths) {
                                next unless ($p0 =~ /^\Q$x\E/);
                                my $i = $paths->{$x};
                                my $f = "$GIT_DIR/svn/$i/revs/$r0";
                                while ($r0 && !-r $f) {
                                        # could be an older revision, too...
                                        $r0--;
                                        $f = "$GIT_DIR/svn/$i/revs/$r0";
                                }
                                unless (-r $f) {
                                        print STDERR "r$r0 of $i not imported,",
                                                                " $dbg\n";
                                        next;
                                }
                                my $r1 = file_to_s($f);
                                $grafts->{$c}->{$r1} = 1;
                        }
                }
        }
}

sub process_merge_msg_matches {
        my ($grafts, $l_map, $u, $p, $c, @matches) = @_;
        my (@strong, @weak);
        foreach (@matches) {
                # merging with ourselves is not interesting
                next if $_ eq $p;
                if ($l_map->{$u}->{$_}) {
                        push @strong, $_;
                } else {
                        push @weak, $_;
                }
        }
        foreach my $w (@weak) {
                last if @strong;
                # no exact match, use branch name as regexp.
                my $re = qr/\Q$w\E/i;
                foreach (keys %{$l_map->{$u}}) {
                        if (/$re/) {
                                push @strong, $_;
                                last;
                        }
                }
                last if @strong;
                $w = basename($w);
                $re = qr/\Q$w\E/i;
                foreach (keys %{$l_map->{$u}}) {
                        if (/$re/) {
                                push @strong, $_;
                                last;
                        }
                }
        }
        my ($rev) = ($c->{m} =~ /^git-svn-id:\s(?:\S+?)\@(\d+)
                                        \s(?:[a-f\d\-]+)$/xsm);
        unless (defined $rev) {
                ($rev) = ($c->{m} =~/^git-svn-id:\s(\d+)
                                        \@(?:[a-f\d\-]+)/xsm);
                return unless defined $rev;
        }
        foreach my $m (@strong) {
                my ($r0, $s0) = find_rev_before($rev, $m);
                $grafts->{$c->{c}}->{$s0} = 1 if defined $s0;
        }
}

sub graft_merge_msg {
        my ($grafts, $l_map, $u, $p, @re) = @_;

        my $x = $l_map->{$u}->{$p};
        my $rl = rev_list_raw($x);
        while (my $c = next_rev_list_entry($rl)) {
                foreach my $re (@re) {
                        my (@br) = ($c->{m} =~ /$re/g);
                        next unless @br;
                        process_merge_msg_matches($grafts,$l_map,$u,$p,$c,@br);
                }
        }
}

sub read_uuid {
        return if $SVN_UUID;
        my $info = shift || svn_info('.');
        $SVN_UUID = $info->{'Repository UUID'} or
                                        croak "Repository UUID unreadable\n";
        s_to_file($SVN_UUID,"$GIT_SVN_DIR/info/uuid");
}

sub quiet_run {
        my $pid = fork;
        defined $pid or croak $!;
        if (!$pid) {
                open my $null, '>', '/dev/null' or croak $!;
                open STDERR, '>&', $null or croak $!;
                open STDOUT, '>&', $null or croak $!;
                exec @_ or croak $!;
        }
        waitpid $pid, 0;
        return $?;
}

sub repo_path_split {
        my $full_url = shift;
        $full_url =~ s#/+$##;

        foreach (@repo_path_split_cache) {
                if ($full_url =~ s#$_##) {
                        my $u = $1;
                        $full_url =~ s#^/+##;
                        return ($u, $full_url);
                }
        }

        my ($url, $path) = ($full_url =~ m!^([a-z\+]+://[^/]*)(.*)$!i);
        $path =~ s#^/+##;
        my @paths = split(m#/+#, $path);

        while (quiet_run(qw/svn ls --non-interactive/, $url)) {
                my $n = shift @paths || last;
                $url .= "/$n";
        }
        push @repo_path_split_cache, qr/^(\Q$url\E)/;
        $path = join('/',@paths);
        return ($url, $path);
}

sub setup_git_svn {
        defined $SVN_URL or croak "SVN repository location required\n";
        unless (-d $GIT_DIR) {
                croak "GIT_DIR=$GIT_DIR does not exist!\n";
        }
        mkpath([$GIT_SVN_DIR]);
        mkpath(["$GIT_SVN_DIR/info"]);
        mkpath([$REV_DIR]);
        s_to_file($SVN_URL,"$GIT_SVN_DIR/info/url");

        open my $fd, '>>', "$GIT_SVN_DIR/info/exclude" or croak $!;
        print $fd '.svn',"\n";
        close $fd or croak $!;
        my ($url, $path) = repo_path_split($SVN_URL);
        s_to_file($url, "$GIT_SVN_DIR/info/repo_url");
        s_to_file($path, "$GIT_SVN_DIR/info/repo_path");
}

sub assert_svn_wc_clean {
        my ($svn_rev) = @_;
        croak "$svn_rev is not an integer!\n" unless ($svn_rev =~ /^\d+$/);
        my $lcr = svn_info('.')->{'Last Changed Rev'};
        if ($svn_rev != $lcr) {
                print STDERR "Checking for copy-tree ... ";
                my @diff = grep(/^Index: /,(safe_qx(qw(svn diff),
                                                "-r$lcr:$svn_rev")));
                if (@diff) {
                        croak "Nope!  Expected r$svn_rev, got r$lcr\n";
                } else {
                        print STDERR "OK!\n";
                }
        }
        my @status = grep(!/^Performing status on external/,(`svn status`));
        @status = grep(!/^\s*$/,@status);
        if (scalar @status) {
                print STDERR "Tree ($SVN_WC) is not clean:\n";
                print STDERR $_ foreach @status;
                croak;
        }
}

sub assert_tree {
        my ($treeish) = @_;
        croak "Not a sha1: $treeish\n" unless $treeish =~ /^$sha1$/o;
        chomp(my $type = `git-cat-file -t $treeish`);
        my $expected;
        while ($type eq 'tag') {
                chomp(($treeish, $type) = `git-cat-file tag $treeish`);
        }
        if ($type eq 'commit') {
                $expected = (grep /^tree /,`git-cat-file commit $treeish`)[0];
                ($expected) = ($expected =~ /^tree ($sha1)$/);
                die "Unable to get tree from $treeish\n" unless $expected;
        } elsif ($type eq 'tree') {
                $expected = $treeish;
        } else {
                die "$treeish is a $type, expected tree, tag or commit\n";
        }

        my $old_index = $ENV{GIT_INDEX_FILE};
        my $tmpindex = $GIT_SVN_INDEX.'.assert-tmp';
        if (-e $tmpindex) {
                unlink $tmpindex or croak $!;
        }
        $ENV{GIT_INDEX_FILE} = $tmpindex;
        index_changes(1);
        chomp(my $tree = `git-write-tree`);
        if ($old_index) {
                $ENV{GIT_INDEX_FILE} = $old_index;
        } else {
                delete $ENV{GIT_INDEX_FILE};
        }
        if ($tree ne $expected) {
                croak "Tree mismatch, Got: $tree, Expected: $expected\n";
        }
        unlink $tmpindex;
}

sub parse_diff_tree {
        my $diff_fh = shift;
        local $/ = "\0";
        my $state = 'meta';
        my @mods;
        while (<$diff_fh>) {
                chomp $_; # this gets rid of the trailing "\0"
                if ($state eq 'meta' && /^:(\d{6})\s(\d{6})\s
                                        $sha1\s($sha1)\s([MTCRAD])\d*$/xo) {
                        push @mods, {   mode_a => $1, mode_b => $2,
                                        sha1_b => $3, chg => $4 };
                        if ($4 =~ /^(?:C|R)$/) {
                                $state = 'file_a';
                        } else {
                                $state = 'file_b';
                        }
                } elsif ($state eq 'file_a') {
                        my $x = $mods[$#mods] or croak "Empty array\n";
                        if ($x->{chg} !~ /^(?:C|R)$/) {
                                croak "Error parsing $_, $x->{chg}\n";
                        }
                        $x->{file_a} = $_;
                        $state = 'file_b';
                } elsif ($state eq 'file_b') {
                        my $x = $mods[$#mods] or croak "Empty array\n";
                        if (exists $x->{file_a} && $x->{chg} !~ /^(?:C|R)$/) {
                                croak "Error parsing $_, $x->{chg}\n";
                        }
                        if (!exists $x->{file_a} && $x->{chg} =~ /^(?:C|R)$/) {
                                croak "Error parsing $_, $x->{chg}\n";
                        }
                        $x->{file_b} = $_;
                        $state = 'meta';
                } else {
                        croak "Error parsing $_\n";
                }
        }
        close $diff_fh or croak $!;

        return \@mods;
}

sub svn_check_prop_executable {
        my $m = shift;
        return if -l $m->{file_b};
        if ($m->{mode_b} =~ /755$/) {
                chmod((0755 &~ umask),$m->{file_b}) or croak $!;
                if ($m->{mode_a} !~ /755$/) {
                        sys(qw(svn propset svn:executable 1), $m->{file_b});
                }
                -x $m->{file_b} or croak "$m->{file_b} is not executable!\n";
        } elsif ($m->{mode_b} !~ /755$/ && $m->{mode_a} =~ /755$/) {
                sys(qw(svn propdel svn:executable), $m->{file_b});
                chmod((0644 &~ umask),$m->{file_b}) or croak $!;
                -x $m->{file_b} and croak "$m->{file_b} is executable!\n";
        }
}

sub svn_ensure_parent_path {
        my $dir_b = dirname(shift);
        svn_ensure_parent_path($dir_b) if ($dir_b ne File::Spec->curdir);
        mkpath([$dir_b]) unless (-d $dir_b);
        sys(qw(svn add -N), $dir_b) unless (-d "$dir_b/.svn");
}

sub precommit_check {
        my $mods = shift;
        my (%rm_file, %rmdir_check, %added_check);

        my %o = ( D => 0, R => 1, C => 2, A => 3, M => 3, T => 3 );
        foreach my $m (sort { $o{$a->{chg}} <=> $o{$b->{chg}} } @$mods) {
                if ($m->{chg} eq 'R') {
                        if (-d $m->{file_b}) {
                                err_dir_to_file("$m->{file_a} => $m->{file_b}");
                        }
                        # dir/$file => dir/file/$file
                        my $dirname = dirname($m->{file_b});
                        while ($dirname ne File::Spec->curdir) {
                                if ($dirname ne $m->{file_a}) {
                                        $dirname = dirname($dirname);
                                        next;
                                }
                                err_file_to_dir("$m->{file_a} => $m->{file_b}");
                        }
                        # baz/zzz => baz (baz is a file)
                        $dirname = dirname($m->{file_a});
                        while ($dirname ne File::Spec->curdir) {
                                if ($dirname ne $m->{file_b}) {
                                        $dirname = dirname($dirname);
                                        next;
                                }
                                err_dir_to_file("$m->{file_a} => $m->{file_b}");
                        }
                }
                if ($m->{chg} =~ /^(D|R)$/) {
                        my $t = $1 eq 'D' ? 'file_b' : 'file_a';
                        $rm_file{ $m->{$t} } = 1;
                        my $dirname = dirname( $m->{$t} );
                        my $basename = basename( $m->{$t} );
                        $rmdir_check{$dirname}->{$basename} = 1;
                } elsif ($m->{chg} =~ /^(?:A|C)$/) {
                        if (-d $m->{file_b}) {
                                err_dir_to_file($m->{file_b});
                        }
                        my $dirname = dirname( $m->{file_b} );
                        my $basename = basename( $m->{file_b} );
                        $added_check{$dirname}->{$basename} = 1;
                        while ($dirname ne File::Spec->curdir) {
                                if ($rm_file{$dirname}) {
                                        err_file_to_dir($m->{file_b});
                                }
                                $dirname = dirname $dirname;
                        }
                }
        }
        return (\%rmdir_check, \%added_check);

        sub err_dir_to_file {
                my $file = shift;
                print STDERR "Node change from directory to file ",
                                "is not supported by Subversion: ",$file,"\n";
                exit 1;
        }
        sub err_file_to_dir {
                my $file = shift;
                print STDERR "Node change from file to directory ",
                                "is not supported by Subversion: ",$file,"\n";
                exit 1;
        }
}

sub svn_checkout_tree {
        my ($svn_rev, $treeish) = @_;
        my $from = file_to_s("$REV_DIR/$svn_rev");
        assert_tree($from);
        print "diff-tree $from $treeish\n";
        my $pid = open my $diff_fh, '-|';
        defined $pid or croak $!;
        if ($pid == 0) {
                my @diff_tree = qw(git-diff-tree -z -r);
                if ($_cp_similarity) {
                        push @diff_tree, "-C$_cp_similarity";
                } else {
                        push @diff_tree, '-C';
                }
                push @diff_tree, '--find-copies-harder' if $_find_copies_harder;
                push @diff_tree, "-l$_l" if defined $_l;
                exec(@diff_tree, $from, $treeish) or croak $!;
        }
        my $mods = parse_diff_tree($diff_fh);
        unless (@$mods) {
                # git can do empty commits, but SVN doesn't allow it...
                return $mods;
        }
        my ($rm, $add) = precommit_check($mods);

        my %o = ( D => 1, R => 0, C => -1, A => 3, M => 3, T => 3 );
        foreach my $m (sort { $o{$a->{chg}} <=> $o{$b->{chg}} } @$mods) {
                if ($m->{chg} eq 'C') {
                        svn_ensure_parent_path( $m->{file_b} );
                        sys(qw(svn cp),         $m->{file_a}, $m->{file_b});
                        apply_mod_line_blob($m);
                        svn_check_prop_executable($m);
                } elsif ($m->{chg} eq 'D') {
                        sys(qw(svn rm --force), $m->{file_b});
                } elsif ($m->{chg} eq 'R') {
                        svn_ensure_parent_path( $m->{file_b} );
                        sys(qw(svn mv --force), $m->{file_a}, $m->{file_b});
                        apply_mod_line_blob($m);
                        svn_check_prop_executable($m);
                } elsif ($m->{chg} eq 'M') {
                        apply_mod_line_blob($m);
                        svn_check_prop_executable($m);
                } elsif ($m->{chg} eq 'T') {
                        sys(qw(svn rm --force),$m->{file_b});
                        apply_mod_line_blob($m);
                        sys(qw(svn add --force), $m->{file_b});
                        svn_check_prop_executable($m);
                } elsif ($m->{chg} eq 'A') {
                        svn_ensure_parent_path( $m->{file_b} );
                        apply_mod_line_blob($m);
                        sys(qw(svn add --force), $m->{file_b});
                        svn_check_prop_executable($m);
                } else {
                        croak "Invalid chg: $m->{chg}\n";
                }
        }

        assert_tree($treeish);
        if ($_rmdir) { # remove empty directories
                handle_rmdir($rm, $add);
        }
        assert_tree($treeish);
        return $mods;
}

# svn ls doesn't work with respect to the current working tree, but what's
# in the repository.  There's not even an option for it... *sigh*
# (added files don't show up and removed files remain in the ls listing)
sub svn_ls_current {
        my ($dir, $rm, $add) = @_;
        chomp(my @ls = safe_qx('svn','ls',$dir));
        my @ret = ();
        foreach (@ls) {
                s#/$##; # trailing slashes are evil
                push @ret, $_ unless $rm->{$dir}->{$_};
        }
        if (exists $add->{$dir}) {
                push @ret, keys %{$add->{$dir}};
        }
        return \@ret;
}

sub handle_rmdir {
        my ($rm, $add) = @_;

        foreach my $dir (sort {length $b <=> length $a} keys %$rm) {
                my $ls = svn_ls_current($dir, $rm, $add);
                next if (scalar @$ls);
                sys(qw(svn rm --force),$dir);

                my $dn = dirname $dir;
                $rm->{ $dn }->{ basename $dir } = 1;
                $ls = svn_ls_current($dn, $rm, $add);
                while (scalar @$ls == 0 && $dn ne File::Spec->curdir) {
                        sys(qw(svn rm --force),$dn);
                        $dir = basename $dn;
                        $dn = dirname $dn;
                        $rm->{ $dn }->{ $dir } = 1;
                        $ls = svn_ls_current($dn, $rm, $add);
                }
        }
}

sub svn_commit_tree {
        my ($svn_rev, $commit) = @_;
        my $commit_msg = "$GIT_SVN_DIR/.svn-commit.tmp.$$";
        my %log_msg = ( msg => '' );
        open my $msg, '>', $commit_msg or croak $!;

        chomp(my $type = `git-cat-file -t $commit`);
        if ($type eq 'commit') {
                my $pid = open my $msg_fh, '-|';
                defined $pid or croak $!;

                if ($pid == 0) {
                        exec(qw(git-cat-file commit), $commit) or croak $!;
                }
                my $in_msg = 0;
                while (<$msg_fh>) {
                        if (!$in_msg) {
                                $in_msg = 1 if (/^\s*$/);
                        } elsif (/^git-svn-id: /) {
                                # skip this, we regenerate the correct one
                                # on re-fetch anyways
                        } else {
                                print $msg $_ or croak $!;
                        }
                }
                close $msg_fh or croak $!;
        }
        close $msg or croak $!;

        if ($_edit || ($type eq 'tree')) {
                my $editor = $ENV{VISUAL} || $ENV{EDITOR} || 'vi';
                system($editor, $commit_msg);
        }

        # file_to_s removes all trailing newlines, so just use chomp() here:
        open $msg, '<', $commit_msg or croak $!;
        { local $/; chomp($log_msg{msg} = <$msg>); }
        close $msg or croak $!;

        my ($oneline) = ($log_msg{msg} =~ /([^\n\r]+)/);
        print "Committing $commit: $oneline\n";

        if (defined $LC_ALL) {
                $ENV{LC_ALL} = $LC_ALL;
        } else {
                delete $ENV{LC_ALL};
        }
        my @ci_output = safe_qx(qw(svn commit -F),$commit_msg);
        $ENV{LC_ALL} = 'C';
        unlink $commit_msg;
        my ($committed) = ($ci_output[$#ci_output] =~ /(\d+)/);
        if (!defined $committed) {
                my $out = join("\n",@ci_output);
                print STDERR "W: Trouble parsing \`svn commit' output:\n\n",
                                $out, "\n\nAssuming English locale...";
                ($committed) = ($out =~ /^Committed revision \d+\./sm);
                defined $committed or die " FAILED!\n",
                        "Commit output failed to parse committed revision!\n",
                print STDERR " OK\n";
        }

        my @svn_up = qw(svn up);
        push @svn_up, '--ignore-externals' unless $_no_ignore_ext;
        if ($committed == ($svn_rev + 1)) {
                push @svn_up, "-r$committed";
                sys(@svn_up);
                my $info = svn_info('.');
                my $date = $info->{'Last Changed Date'} or die "Missing date\n";
                if ($info->{'Last Changed Rev'} != $committed) {
                        croak "$info->{'Last Changed Rev'} != $committed\n"
                }
                my ($Y,$m,$d,$H,$M,$S,$tz) = ($date =~
                                        /(\d{4})\-(\d\d)\-(\d\d)\s
                                         (\d\d)\:(\d\d)\:(\d\d)\s([\-\+]\d+)/x)
                                         or croak "Failed to parse date: $date\n";
                $log_msg{date} = "$tz $Y-$m-$d $H:$M:$S";
                $log_msg{author} = $info->{'Last Changed Author'};
                $log_msg{revision} = $committed;
                $log_msg{msg} .= "\n";
                my $parent = file_to_s("$REV_DIR/$svn_rev");
                git_commit(\%log_msg, $parent, $commit);
                return $committed;
        }
        # resync immediately
        push @svn_up, "-r$svn_rev";
        sys(@svn_up);
        return fetch("$committed=$commit")->{revision};
}

sub rev_list_raw {
        my (@args) = @_;
        my $pid = open my $fh, '-|';
        defined $pid or croak $!;
        if (!$pid) {
                exec(qw/git-rev-list --pretty=raw/, @args) or croak $!;
        }
        return { fh => $fh, t => { } };
}

sub next_rev_list_entry {
        my $rl = shift;
        my $fh = $rl->{fh};
        my $x = $rl->{t};
        while (<$fh>) {
                if (/^commit ($sha1)$/o) {
                        if ($x->{c}) {
                                $rl->{t} = { c => $1 };
                                return $x;
                        } else {
                                $x->{c} = $1;
                        }
                } elsif (/^parent ($sha1)$/o) {
                        $x->{p}->{$1} = 1;
                } elsif (s/^    //) {
                        $x->{m} ||= '';
                        $x->{m} .= $_;
                }
        }
        return ($x != $rl->{t}) ? $x : undef;
}

# read the entire log into a temporary file (which is removed ASAP)
# and store the file handle + parser state
sub svn_log_raw {
        my (@log_args) = @_;
        my $log_fh = IO::File->new_tmpfile or croak $!;
        my $pid = fork;
        defined $pid or croak $!;
        if (!$pid) {
                open STDOUT, '>&', $log_fh or croak $!;
                exec (qw(svn log), @log_args) or croak $!
        }
        waitpid $pid, 0;
        croak $? if $?;
        seek $log_fh, 0, 0 or croak $!;
        return { state => 'sep', fh => $log_fh };
}

sub next_log_entry {
        my $log = shift; # retval of svn_log_raw()
        my $ret = undef;
        my $fh = $log->{fh};

        while (<$fh>) {
                chomp;
                if (/^\-{72}$/) {
                        if ($log->{state} eq 'msg') {
                                if ($ret->{lines}) {
                                        $ret->{msg} .= $_."\n";
                                        unless(--$ret->{lines}) {
                                                $log->{state} = 'sep';
                                        }
                                } else {
                                        croak "Log parse error at: $_\n",
                                                $ret->{revision},
                                                "\n";
                                }
                                next;
                        }
                        if ($log->{state} ne 'sep') {
                                croak "Log parse error at: $_\n",
                                        "state: $log->{state}\n",
                                        $ret->{revision},
                                        "\n";
                        }
                        $log->{state} = 'rev';

                        # if we have an empty log message, put something there:
                        if ($ret) {
                                $ret->{msg} ||= "\n";
                                delete $ret->{lines};
                                return $ret;
                        }
                        next;
                }
                if ($log->{state} eq 'rev' && s/^r(\d+)\s*\|\s*//) {
                        my $rev = $1;
                        my ($author, $date, $lines) = split(/\s*\|\s*/, $_, 3);
                        ($lines) = ($lines =~ /(\d+)/);
                        my ($Y,$m,$d,$H,$M,$S,$tz) = ($date =~
                                        /(\d{4})\-(\d\d)\-(\d\d)\s
                                         (\d\d)\:(\d\d)\:(\d\d)\s([\-\+]\d+)/x)
                                         or croak "Failed to parse date: $date\n";
                        $ret = {        revision => $rev,
                                        date => "$tz $Y-$m-$d $H:$M:$S",
                                        author => $author,
                                        lines => $lines,
                                        msg => '' };
                        if (defined $_authors && ! defined $users{$author}) {
                                die "Author: $author not defined in ",
                                                "$_authors file\n";
                        }
                        $log->{state} = 'msg_start';
                        next;
                }
                # skip the first blank line of the message:
                if ($log->{state} eq 'msg_start' && /^$/) {
                        $log->{state} = 'msg';
                } elsif ($log->{state} eq 'msg') {
                        if ($ret->{lines}) {
                                $ret->{msg} .= $_."\n";
                                unless (--$ret->{lines}) {
                                        $log->{state} = 'sep';
                                }
                        } else {
                                croak "Log parse error at: $_\n",
                                        $ret->{revision},"\n";
                        }
                }
        }
        return $ret;
}

sub svn_info {
        my $url = shift || $SVN_URL;

        my $pid = open my $info_fh, '-|';
        defined $pid or croak $!;

        if ($pid == 0) {
                exec(qw(svn info),$url) or croak $!;
        }

        my $ret = {};
        # only single-lines seem to exist in svn info output
        while (<$info_fh>) {
                chomp $_;
                if (m#^([^:]+)\s*:\s*(\S.*)$#) {
                        $ret->{$1} = $2;
                        push @{$ret->{-order}}, $1;
                }
        }
        close $info_fh or croak $!;
        return $ret;
}

sub sys { system(@_) == 0 or croak $? }

sub eol_cp {
        my ($from, $to) = @_;
        my $es = svn_propget_base('svn:eol-style', $to);
        open my $rfd, '<', $from or croak $!;
        binmode $rfd or croak $!;
        open my $wfd, '>', $to or croak $!;
        binmode $wfd or croak $!;

        my $eol = $EOL{$es} or undef;
        my $buf;
        use bytes;
        while (1) {
                my ($r, $w, $t);
                defined($r = sysread($rfd, $buf, 4096)) or croak $!;
                return unless $r;
                if ($eol) {
                        if ($buf =~ /\015$/) {
                                my $c;
                                defined($r = sysread($rfd,$c,1)) or croak $!;
                                $buf .= $c if $r > 0;
                        }
                        $buf =~ s/(?:\015\012|\015|\012)/$eol/gs;
                        $r = length($buf);
                }
                for ($w = 0; $w < $r; $w += $t) {
                        $t = syswrite($wfd, $buf, $r - $w, $w) or croak $!;
                }
        }
        no bytes;
}

sub do_update_index {
        my ($z_cmd, $cmd, $no_text_base) = @_;

        my $z = open my $p, '-|';
        defined $z or croak $!;
        unless ($z) { exec @$z_cmd or croak $! }

        my $pid = open my $ui, '|-';
        defined $pid or croak $!;
        unless ($pid) {
                exec('git-update-index',"--$cmd",'-z','--stdin') or croak $!;
        }
        local $/ = "\0";
        while (my $x = <$p>) {
                chomp $x;
                if (!$no_text_base && lstat $x && ! -l _ &&
                                svn_propget_base('svn:keywords', $x)) {
                        my $mode = -x _ ? 0755 : 0644;
                        my ($v,$d,$f) = File::Spec->splitpath($x);
                        my $tb = File::Spec->catfile($d, '.svn', 'tmp',
                                                'text-base',"$f.svn-base");
                        $tb =~ s#^/##;
                        unless (-f $tb) {
                                $tb = File::Spec->catfile($d, '.svn',
                                                'text-base',"$f.svn-base");
                                $tb =~ s#^/##;
                        }
                        unlink $x or croak $!;
                        eol_cp($tb, $x);
                        chmod(($mode &~ umask), $x) or croak $!;
                }
                print $ui $x,"\0";
        }
        close $ui or croak $!;
}

sub index_changes {
        my $no_text_base = shift;
        do_update_index([qw/git-diff-files --name-only -z/],
                        'remove',
                        $no_text_base);
        do_update_index([qw/git-ls-files -z --others/,
                                "--exclude-from=$GIT_SVN_DIR/info/exclude"],
                        'add',
                        $no_text_base);
}

sub s_to_file {
        my ($str, $file, $mode) = @_;
        open my $fd,'>',$file or croak $!;
        print $fd $str,"\n" or croak $!;
        close $fd or croak $!;
        chmod ($mode &~ umask, $file) if (defined $mode);
}

sub file_to_s {
        my $file = shift;
        open my $fd,'<',$file or croak "$!: file: $file\n";
        local $/;
        my $ret = <$fd>;
        close $fd or croak $!;
        $ret =~ s/\s*$//s;
        return $ret;
}

sub assert_revision_unknown {
        my $revno = shift;
        if (-f "$REV_DIR/$revno") {
                croak "$REV_DIR/$revno already exists! ",
                                "Why are we refetching it?";
        }
}

sub trees_eq {
        my ($x, $y) = @_;
        my @x = safe_qx('git-cat-file','commit',$x);
        my @y = safe_qx('git-cat-file','commit',$y);
        if (($y[0] ne $x[0]) || $x[0] !~ /^tree $sha1\n$/
                                || $y[0] !~ /^tree $sha1\n$/) {
                print STDERR "Trees not equal: $y[0] != $x[0]\n";
                return 0
        }
        return 1;
}

sub assert_revision_eq_or_unknown {
        my ($revno, $commit) = @_;
        if (-f "$REV_DIR/$revno") {
                my $current = file_to_s("$REV_DIR/$revno");
                if (($commit ne $current) && !trees_eq($commit, $current)) {
                        croak "$REV_DIR/$revno already exists!\n",
                                "current: $current\nexpected: $commit\n";
                }
                return;
        }
}

sub git_commit {
        my ($log_msg, @parents) = @_;
        assert_revision_unknown($log_msg->{revision});
        my $out_fh = IO::File->new_tmpfile or croak $!;

        map_tree_joins() if (@_branch_from && !%tree_map);

        # commit parents can be conditionally bound to a particular
        # svn revision via: "svn_revno=commit_sha1", filter them out here:
        my @exec_parents;
        foreach my $p (@parents) {
                next unless defined $p;
                if ($p =~ /^(\d+)=($sha1_short)$/o) {
                        if ($1 == $log_msg->{revision}) {
                                push @exec_parents, $2;
                        }
                } else {
                        push @exec_parents, $p if $p =~ /$sha1_short/o;
                }
        }

        my $pid = fork;
        defined $pid or croak $!;
        if ($pid == 0) {
                $ENV{GIT_INDEX_FILE} = $GIT_SVN_INDEX;
                index_changes();
                chomp(my $tree = `git-write-tree`);
                croak $? if $?;
                if (exists $tree_map{$tree}) {
                        my %seen_parent = map { $_ => 1 } @exec_parents;
                        foreach (@{$tree_map{$tree}}) {
                                # MAXPARENT is defined to 16 in commit-tree.c:
                                if ($seen_parent{$_} || @exec_parents > 16) {
                                        next;
                                }
                                push @exec_parents, $_;
                                $seen_parent{$_} = 1;
                        }
                }
                my $msg_fh = IO::File->new_tmpfile or croak $!;
                print $msg_fh $log_msg->{msg}, "\ngit-svn-id: ",
                                        "$SVN_URL\@$log_msg->{revision}",
                                        " $SVN_UUID\n" or croak $!;
                $msg_fh->flush == 0 or croak $!;
                seek $msg_fh, 0, 0 or croak $!;

                set_commit_env($log_msg);

                my @exec = ('git-commit-tree',$tree);
                push @exec, '-p', $_  foreach @exec_parents;
                open STDIN, '<&', $msg_fh or croak $!;
                open STDOUT, '>&', $out_fh or croak $!;
                exec @exec or croak $!;
        }
        waitpid($pid,0);
        croak $? if $?;

        $out_fh->flush == 0 or croak $!;
        seek $out_fh, 0, 0 or croak $!;
        chomp(my $commit = do { local $/; <$out_fh> });
        if ($commit !~ /^$sha1$/o) {
                croak "Failed to commit, invalid sha1: $commit\n";
        }
        my @update_ref = ('git-update-ref',"refs/remotes/$GIT_SVN",$commit);
        if (my $primary_parent = shift @exec_parents) {
                $pid = fork;
                defined $pid or croak $!;
                if (!$pid) {
                        close STDERR;
                        close STDOUT;
                        exec 'git-rev-parse','--verify',
                                        "refs/remotes/$GIT_SVN^0" or croak $!;
                }
                waitpid $pid, 0;
                push @update_ref, $primary_parent unless $?;
        }
        sys(@update_ref);
        sys('git-update-ref',"svn/$GIT_SVN/revs/$log_msg->{revision}",$commit);
        print "r$log_msg->{revision} = $commit\n";
        if ($_repack && (--$_repack_nr == 0)) {
                $_repack_nr = $_repack;
                sys("git repack $_repack_flags");
        }
        return $commit;
}

sub set_commit_env {
        my ($log_msg) = @_;
        my $author = $log_msg->{author};
        my ($name,$email) = defined $users{$author} ?  @{$users{$author}}
                                : ($author,"$author\@$SVN_UUID");
        $ENV{GIT_AUTHOR_NAME} = $ENV{GIT_COMMITTER_NAME} = $name;
        $ENV{GIT_AUTHOR_EMAIL} = $ENV{GIT_COMMITTER_EMAIL} = $email;
        $ENV{GIT_AUTHOR_DATE} = $ENV{GIT_COMMITTER_DATE} = $log_msg->{date};
}

sub apply_mod_line_blob {
        my $m = shift;
        if ($m->{mode_b} =~ /^120/) {
                blob_to_symlink($m->{sha1_b}, $m->{file_b});
        } else {
                blob_to_file($m->{sha1_b}, $m->{file_b});
        }
}

sub blob_to_symlink {
        my ($blob, $link) = @_;
        defined $link or croak "\$link not defined!\n";
        croak "Not a sha1: $blob\n" unless $blob =~ /^$sha1$/o;
        if (-l $link || -f _) {
                unlink $link or croak $!;
        }

        my $dest = `git-cat-file blob $blob`; # no newline, so no chomp
        symlink $dest, $link or croak $!;
}

sub blob_to_file {
        my ($blob, $file) = @_;
        defined $file or croak "\$file not defined!\n";
        croak "Not a sha1: $blob\n" unless $blob =~ /^$sha1$/o;
        if (-l $file || -f _) {
                unlink $file or croak $!;
        }

        open my $blob_fh, '>', $file or croak "$!: $file\n";
        my $pid = fork;
        defined $pid or croak $!;

        if ($pid == 0) {
                open STDOUT, '>&', $blob_fh or croak $!;
                exec('git-cat-file','blob',$blob) or croak $!;
        }
        waitpid $pid, 0;
        croak $? if $?;

        close $blob_fh or croak $!;
}

sub safe_qx {
        my $pid = open my $child, '-|';
        defined $pid or croak $!;
        if ($pid == 0) {
                exec(@_) or croak $!;
        }
        my @ret = (<$child>);
        close $child or croak $?;
        die $? if $?; # just in case close didn't error out
        return wantarray ? @ret : join('',@ret);
}

sub svn_compat_check {
        my @co_help = safe_qx(qw(svn co -h));
        unless (grep /ignore-externals/,@co_help) {
                print STDERR "W: Installed svn version does not support ",
                                "--ignore-externals\n";
                $_no_ignore_ext = 1;
        }
        if (grep /usage: checkout URL\[\@REV\]/,@co_help) {
                $_svn_co_url_revs = 1;
        }
        if (grep /\[TARGET\[\@REV\]\.\.\.\]/, `svn propget -h`) {
                $_svn_pg_peg_revs = 1;
        }

        # I really, really hope nobody hits this...
        unless (grep /stop-on-copy/, (safe_qx(qw(svn log -h)))) {
                print STDERR <<'';
W: The installed svn version does not support the --stop-on-copy flag in
   the log command.
   Lets hope the directory you're tracking is not a branch or tag
   and was never moved within the repository...

                $_no_stop_copy = 1;
        }
}

# *sigh*, new versions of svn won't honor -r<rev> without URL@<rev>,
# (and they won't honor URL@<rev> without -r<rev>, too!)
sub svn_cmd_checkout {
        my ($url, $rev, $dir) = @_;
        my @cmd = ('svn','co', "-r$rev");
        push @cmd, '--ignore-externals' unless $_no_ignore_ext;
        $url .= "\@$rev" if $_svn_co_url_revs;
        sys(@cmd, $url, $dir);
}

sub check_upgrade_needed {
        my $old = eval {
                my $pid = open my $child, '-|';
                defined $pid or croak $!;
                if ($pid == 0) {
                        close STDERR;
                        exec('git-rev-parse',"$GIT_SVN-HEAD") or croak $!;
                }
                my @ret = (<$child>);
                close $child or croak $?;
                die $? if $?; # just in case close didn't error out
                return wantarray ? @ret : join('',@ret);
        };
        return unless $old;
        my $head = eval { safe_qx('git-rev-parse',"refs/remotes/$GIT_SVN") };
        if ($@ || !$head) {
                print STDERR "Please run: $0 rebuild --upgrade\n";
                exit 1;
        }
}

# fills %tree_map with a reverse mapping of trees to commits.  Useful
# for finding parents to commit on.
sub map_tree_joins {
        my %seen;
        foreach my $br (@_branch_from) {
                my $pid = open my $pipe, '-|';
                defined $pid or croak $!;
                if ($pid == 0) {
                        exec(qw(git-rev-list --topo-order --pretty=raw), $br)
                                                                or croak $!;
                }
                while (<$pipe>) {
                        if (/^commit ($sha1)$/o) {
                                my $commit = $1;

                                # if we've seen a commit,
                                # we've seen its parents
                                last if $seen{$commit};
                                my ($tree) = (<$pipe> =~ /^tree ($sha1)$/o);
                                unless (defined $tree) {
                                        die "Failed to parse commit $commit\n";
                                }
                                push @{$tree_map{$tree}}, $commit;
                                $seen{$commit} = 1;
                        }
                }
                close $pipe; # we could be breaking the pipe early
        }
}

sub load_all_refs {
        if (@_branch_from) {
                print STDERR '--branch|-b parameters are ignored when ',
                        "--branch-all-refs|-B is passed\n";
        }

        # don't worry about rev-list on non-commit objects/tags,
        # it shouldn't blow up if a ref is a blob or tree...
        chomp(@_branch_from = `git-rev-parse --symbolic --all`);
}

# '<svn username> = real-name <email address>' mapping based on git-svnimport:
sub load_authors {
        open my $authors, '<', $_authors or die "Can't open $_authors $!\n";
        while (<$authors>) {
                chomp;
                next unless /^(\S+?)\s*=\s*(.+?)\s*<(.+)>\s*$/;
                my ($user, $name, $email) = ($1, $2, $3);
                $users{$user} = [$name, $email];
        }
        close $authors or croak $!;
}

sub rload_authors {
        open my $authors, '<', $_authors or die "Can't open $_authors $!\n";
        while (<$authors>) {
                chomp;
                next unless /^(\S+?)\s*=\s*(.+?)\s*<(.+)>\s*$/;
                my ($user, $name, $email) = ($1, $2, $3);
                $rusers{"$name <$email>"} = $user;
        }
        close $authors or croak $!;
}

sub svn_propget_base {
        my ($p, $f) = @_;
        $f .= '@BASE' if $_svn_pg_peg_revs;
        return safe_qx(qw/svn propget/, $p, $f);
}

sub git_svn_each {
        my $sub = shift;
        foreach (`git-rev-parse --symbolic --all`) {
                next unless s#^refs/remotes/##;
                chomp $_;
                next unless -f "$GIT_DIR/svn/$_/info/url";
                &$sub($_);
        }
}

sub migration_check {
        return if (-d "$GIT_DIR/svn" || !-d $GIT_DIR);
        print "Upgrading repository...\n";
        unless (-d "$GIT_DIR/svn") {
                mkdir "$GIT_DIR/svn" or croak $!;
        }
        print "Data from a previous version of git-svn exists, but\n\t",
                                "$GIT_SVN_DIR\n\t(required for this version ",
                                "($VERSION) of git-svn) does not.\n";

        foreach my $x (`git-rev-parse --symbolic --all`) {
                next unless $x =~ s#^refs/remotes/##;
                chomp $x;
                next unless -f "$GIT_DIR/$x/info/url";
                my $u = eval { file_to_s("$GIT_DIR/$x/info/url") };
                next unless $u;
                my $dn = dirname("$GIT_DIR/svn/$x");
                mkpath([$dn]) unless -d $dn;
                rename "$GIT_DIR/$x", "$GIT_DIR/svn/$x" or croak "$!: $x";
                my ($url, $path) = repo_path_split($u);
                s_to_file($url, "$GIT_DIR/svn/$x/info/repo_url");
                s_to_file($path, "$GIT_DIR/svn/$x/info/repo_path");
        }
        print "Done upgrading.\n";
}

sub find_rev_before {
        my ($r, $git_svn_id) = @_;
        my @revs = map { basename $_ } <$GIT_DIR/svn/$git_svn_id/revs/*>;
        foreach my $r0 (sort { $b <=> $a } @revs) {
                next if $r0 >= $r;
                return ($r0, file_to_s("$GIT_DIR/svn/$git_svn_id/revs/$r0"));
        }
        return (undef, undef);
}

sub init_vars {
        $GIT_SVN ||= $ENV{GIT_SVN_ID} || 'git-svn';
        $GIT_SVN_DIR = "$GIT_DIR/svn/$GIT_SVN";
        $GIT_SVN_INDEX = "$GIT_SVN_DIR/index";
        $SVN_URL = undef;
        $REV_DIR = "$GIT_SVN_DIR/revs";
        $SVN_WC = "$GIT_SVN_DIR/tree";
}

# convert GetOpt::Long specs for use by git-repo-config
sub read_repo_config {
        return unless -d $GIT_DIR;
        my $opts = shift;
        foreach my $o (keys %$opts) {
                my $v = $opts->{$o};
                my ($key) = ($o =~ /^([a-z\-]+)/);
                $key =~ s/-//g;
                my $arg = 'git-repo-config';
                $arg .= ' --int' if ($o =~ /[:=]i$/);
                $arg .= ' --bool' if ($o !~ /[:=][sfi]$/);
                if (ref $v eq 'ARRAY') {
                        chomp(my @tmp = `$arg --get-all svn.$key`);
                        @$v = @tmp if @tmp;
                } else {
                        chomp(my $tmp = `$arg --get svn.$key`);
                        if ($tmp && !($arg =~ / --bool / && $tmp eq 'false')) {
                                $$v = $tmp;
                        }
                }
        }
}

sub set_default_vals {
        if (defined $_repack) {
                $_repack = 1000 if ($_repack <= 0);
                $_repack_nr = $_repack;
                $_repack_flags ||= '';
        }
}

sub read_grafts {
        my $gr_file = shift;
        my ($grafts, $comments) = ({}, {});
        if (open my $fh, '<', $gr_file) {
                my @tmp;
                while (<$fh>) {
                        if (/^($sha1)\s+/) {
                                my $c = $1;
                                if (@tmp) {
                                        @{$comments->{$c}} = @tmp;
                                        @tmp = ();
                                }
                                foreach my $p (split /\s+/, $_) {
                                        $grafts->{$c}->{$p} = 1;
                                }
                        } else {
                                push @tmp, $_;
                        }
                }
                close $fh or croak $!;
                @{$comments->{'END'}} = @tmp if @tmp;
        }
        return ($grafts, $comments);
}

sub write_grafts {
        my ($grafts, $comments, $gr_file) = @_;

        open my $fh, '>', $gr_file or croak $!;
        foreach my $c (sort keys %$grafts) {
                if ($comments->{$c}) {
                        print $fh $_ foreach @{$comments->{$c}};
                }
                my $p = $grafts->{$c};
                delete $p->{$c}; # commits are not self-reproducing...
                my $pid = open my $ch, '-|';
                defined $pid or croak $!;
                if (!$pid) {
                        exec(qw/git-cat-file commit/, $c) or croak $!;
                }
                while (<$ch>) {
                        if (/^parent ([a-f\d]{40})/) {
                                $p->{$1} = 1;
                        } else {
                                last unless /^\S/i;
                        }
                }
                close $ch; # breaking the pipe
                print $fh $c, ' ', join(' ', sort keys %$p),"\n";
        }
        if ($comments->{'END'}) {
                print $fh $_ foreach @{$comments->{'END'}};
        }
        close $fh or croak $!;
}

sub read_url_paths {
        my $l_map = {};
        git_svn_each(sub { my $x = shift;
                        my $u = file_to_s("$GIT_DIR/svn/$x/info/repo_url");
                        my $p = file_to_s("$GIT_DIR/svn/$x/info/repo_path");
                        # we hate trailing slashes
                        if ($u =~ s#(?:^\/+|\/+$)##g) {
                                s_to_file($u,"$GIT_DIR/svn/$x/info/repo_url");
                        }
                        if ($p =~ s#(?:^\/+|\/+$)##g) {
                                s_to_file($p,"$GIT_DIR/svn/$x/info/repo_path");
                        }
                        $l_map->{$u}->{$p} = $x;
                        });
        return $l_map;
}

sub extract_metadata {
        my $id = shift;
        my ($url, $rev, $uuid) = ($id =~ /^git-svn-id:\s(\S+?)\@(\d+)
                                                        \s([a-f\d\-]+)$/x);
        if (!$rev || !$uuid || !$url) {
                # some of the original repositories I made had
                # indentifiers like this:
                ($rev, $uuid) = ($id =~/^git-svn-id:\s(\d+)\@([a-f\d\-]+)/);
        }
        return ($url, $rev, $uuid);
}

sub tz_to_s_offset {
        my ($tz) = @_;
        $tz =~ s/(\d\d)$//;
        return ($1 * 60) + ($tz * 3600);
}

sub setup_pager { # translated to Perl from pager.c
        return unless (-t *STDOUT);
        my $pager = $ENV{PAGER};
        if (!defined $pager) {
                $pager = 'less';
        } elsif (length $pager == 0 || $pager eq 'cat') {
                return;
        }
        pipe my $rfd, my $wfd or return;
        defined(my $pid = fork) or croak $!;
        if (!$pid) {
                open STDOUT, '>&', $wfd or croak $!;
                return;
        }
        open STDIN, '<&', $rfd or croak $!;
        $ENV{LESS} ||= '-S';
        exec $pager or croak "Can't run pager: $!\n";;
}

sub get_author_info {
        my ($dest, $author, $t, $tz) = @_;
        $author =~ s/(?:^\s*|\s*$)//g;
        my $_a;
        if ($_authors) {
                $_a = $rusers{$author} || undef;
        }
        if (!$_a) {
                ($_a) = ($author =~ /<([^>]+)\@[^>]+>$/);
        }
        $dest->{t} = $t;
        $dest->{tz} = $tz;
        $dest->{a} = $_a;
        # Date::Parse isn't in the standard Perl distro :(
        if ($tz =~ s/^\+//) {
                $t += tz_to_s_offset($tz);
        } elsif ($tz =~ s/^\-//) {
                $t -= tz_to_s_offset($tz);
        }
        $dest->{t_utc} = $t;
}

sub process_commit {
        my ($c, $r_min, $r_max, $defer) = @_;
        if (defined $r_min && defined $r_max) {
                if ($r_min == $c->{r} && $r_min == $r_max) {
                        show_commit($c);
                        return 0;
                }
                return 1 if $r_min == $r_max;
                if ($r_min < $r_max) {
                        # we need to reverse the print order
                        return 0 if (defined $_limit && --$_limit < 0);
                        push @$defer, $c;
                        return 1;
                }
                if ($r_min != $r_max) {
                        return 1 if ($r_min < $c->{r});
                        return 1 if ($r_max > $c->{r});
                }
        }
        return 0 if (defined $_limit && --$_limit < 0);
        show_commit($c);
        return 1;
}

sub show_commit {
        my $c = shift;
        if ($_oneline) {
                my $x = "\n";
                if (my $l = $c->{l}) {
                        while ($l->[0] =~ /^\s*$/) { shift @$l }
                        $x = $l->[0];
                }
                $_l_fmt ||= 'A' . length($c->{r});
                print 'r',pack($_l_fmt, $c->{r}),' | ';
                print "$c->{c} | " if $_show_commit;
                print $x;
        } else {
                show_commit_normal($c);
        }
}

sub show_commit_normal {
        my ($c) = @_;
        print '-' x72, "\nr$c->{r} | ";
        print "$c->{c} | " if $_show_commit;
        print "$c->{a} | ", strftime("%Y-%m-%d %H:%M:%S %z (%a, %d %b %Y)",
                                 localtime($c->{t_utc})), ' | ';
        my $nr_line = 0;

        if (my $l = $c->{l}) {
                while ($l->[$#$l] eq "\n" && $l->[($#$l - 1)] eq "\n") {
                        pop @$l;
                }
                $nr_line = scalar @$l;
                if (!$nr_line) {
                        print "1 line\n\n\n";
                } else {
                        if ($nr_line == 1) {
                                $nr_line = '1 line';
                        } else {
                                $nr_line .= ' lines';
                        }
                        print $nr_line, "\n\n";
                        print $_ foreach @$l;
                }
        } else {
                print "1 line\n\n";

        }
        foreach my $x (qw/raw diff/) {
                if ($c->{$x}) {
                        print "\n";
                        print $_ foreach @{$c->{$x}}
                }
        }
}

__END__

Data structures:

$svn_log hashref (as returned by svn_log_raw)
{
        fh => file handle of the log file,
        state => state of the log file parser (sep/msg/rev/msg_start...)
}

$log_msg hashref as returned by next_log_entry($svn_log)
{
        msg => 'whitespace-formatted log entry
',                                              # trailing newline is preserved
        revision => '8',                        # integer
        date => '2004-02-24T17:01:44.108345Z',  # commit date
        author => 'committer name'
};


@mods = array of diff-index line hashes, each element represents one line
        of diff-index output

diff-index line ($m hash)
{
        mode_a => first column of diff-index output, no leading ':',
        mode_b => second column of diff-index output,
        sha1_b => sha1sum of the final blob,
        chg => change type [MCRADT],
        file_a => original file name of a file (iff chg is 'C' or 'R')
        file_b => new/current file name of a file (any chg)
}
;