#!/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 $GIT_SVN_DIR $REVDB/;
$AUTHOR = 'Eric Wong <normalperson@yhbt.net>';
$VERSION = '@@GIT_VERSION@@';

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';
$| = 1; # unbuffer STDOUT

sub fatal (@) { print STDERR $@; exit 1 }
# 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 File::Copy qw/copy/;
use POSIX qw/strftime/;
use IPC::Open3;
use Memoize;
memoize('revisions_eq');
memoize('cmt_metadata');
memoize('get_commit_time');

my ($SVN, $_use_lib);

sub nag_lib {
        print STDERR <<EOF;
! Please consider installing the SVN Perl libraries (version 1.1.0 or
! newer).  You will generally get better performance and fewer bugs,
! especially if you:
! 1) have a case-insensitive filesystem
! 2) replace symlinks with files (and vice-versa) in commits

EOF
}

$_use_lib = 1 unless $ENV{GIT_SVN_NO_LIB};
libsvn_load();
nag_lib() unless $_use_lib;

my $_optimize_commits = 1 unless $ENV{GIT_SVN_NO_OPTIMIZE_COMMITS};
my $sha1 = qr/[a-f\d]{40}/;
my $sha1_short = qr/[a-f\d]{4,40}/;
my $_esc_color = qr/(?:\033\[(?:(?:\d+;)*\d*)?m)*/;
my ($_revision,$_stdin,$_no_ignore_ext,$_no_stop_copy,$_help,$_rmdir,$_edit,
        $_find_copies_harder, $_l, $_cp_similarity, $_cp_remote,
        $_repack, $_repack_nr, $_repack_flags, $_q,
        $_message, $_file, $_follow_parent, $_no_metadata,
        $_template, $_shared, $_no_default_regex, $_no_graft_copy,
        $_limit, $_verbose, $_incremental, $_oneline, $_l_fmt, $_show_commit,
        $_version, $_upgrade, $_authors, $_branch_all_refs, @_opt_m,
        $_merge, $_strategy, $_dry_run, $_ignore_nodate, $_non_recursive,
        $_username, $_config_dir, $_no_auth_cache, $_xfer_delta,
        $_pager, $_color);
my (@_branch_from, %tree_map, %users, %rusers, %equiv);
my ($_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,
                'follow-parent|follow' => \$_follow_parent,
                'branch-all-refs|B' => \$_branch_all_refs,
                'authors-file|A=s' => \$_authors,
                'repack:i' => \$_repack,
                'no-metadata' => \$_no_metadata,
                'quiet|q' => \$_q,
                'username=s' => \$_username,
                'config-dir=s' => \$_config_dir,
                'no-auth-cache' => \$_no_auth_cache,
                'ignore-nodate' => \$_ignore_nodate,
                '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 );
my %cmt_opts = ( 'edit|e' => \$_edit,
                'rmdir' => \$_rmdir,
                'find-copies-harder' => \$_find_copies_harder,
                'l=i' => \$_l,
                'copy-similarity|C=i'=> \$_cp_similarity
);

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, %cmt_opts, %fc_opts, } ],
        'show-ignore' => [ \&show_ignore, "Show svn:ignore listings",
                        { 'revision|r=i' => \$_revision } ],
        rebuild => [ \&rebuild, "Rebuild git-svn metadata (after git clone)",
                        { 'no-ignore-externals' => \$_no_ignore_ext,
                          'copy-remote|remote=s' => \$_cp_remote,
                          'upgrade' => \$_upgrade } ],
        'graft-branches' => [ \&graft_branches,
                        'Detect merges/branches from already imported history',
                        { 'merge-rx|m' => \@_opt_m,
                          'branch|b=s' => \@_branch_from,
                          'branch-all-refs|B' => \$_branch_all_refs,
                          '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,
                          'non-recursive' => \$_non_recursive,
                          'authors-file|A=s' => \$_authors,
                          'color' => \$_color,
                          'pager=s' => \$_pager,
                        } ],
        'commit-diff' => [ \&commit_diff, 'Commit a diff between two trees',
                        { 'message|m=s' => \$_message,
                          'file|F=s' => \$_file,
                          'revision|r=s' => \$_revision,
                        %cmt_opts } ],
        dcommit => [ \&dcommit, 'Commit several diffs to merge with upstream',
                        { 'merge|m|M' => \$_merge,
                          'strategy|s=s' => \$_strategy,
                          'dry-run|n' => \$_dry_run,
                        %cmt_opts } ],
);

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() unless $_use_lib;
migration_check() unless $cmd =~ /^(?:init|rebuild|multi-init|commit-diff)$/;
$cmd{$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 $fd '  ',pack('A17',$_),$cmd{$_}->[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 21, 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 {
        if (quiet_run(qw/git-rev-parse --verify/,"refs/remotes/$GIT_SVN^0")) {
                copy_remote_ref();
        }
        $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 (!defined $rev || !$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));

                unless (defined $latest) {
                        if (!$SVN_URL && !$url) {
                                croak "SVN repository location required: $url\n";
                        }
                        $SVN_URL ||= $url;
                        $SVN_UUID ||= $uuid;
                        setup_git_svn();
                        $latest = $rev;
                }
                revdb_set($REVDB, $rev, $c);
                print "r$rev = $c\n";
                $newest_rev = $rev if ($rev > $newest_rev);
        }
        close $rev_list or croak $?;

        goto out if $_use_lib;
        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 $?;
out:
        if ($_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 {
        my $url = shift or die "SVN repository location required " .
                                "as a command-line argument\n";
        $url =~ s!/+$!!; # strip trailing slash

        if (my $repo_path = shift) {
                unless (-d $repo_path) {
                        mkpath([$repo_path]);
                }
                $GIT_DIR = $ENV{GIT_DIR} = $repo_path . "/.git";
                init_vars();
        }

        $SVN_URL = $url;
        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 {
        check_upgrade_needed();
        $SVN_URL ||= file_to_s("$GIT_SVN_DIR/info/url");
        my $ret = $_use_lib ? fetch_lib(@_) : fetch_cmd(@_);
        if ($ret->{commit} && quiet_run(qw(git-rev-parse --verify
                                                refs/heads/master^0))) {
                sys(qw(git-update-ref refs/heads/master),$ret->{commit});
        }
        return $ret;
}

sub fetch_cmd {
        my (@parents) = @_;
        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";
        # don't need last_revision from grab_base_rev() because
        # user could've specified a different revision to skip (they
        # didn't want to import certain revisions into git for whatever
        # reason, so trust $base->{revision} instead.
        my (undef, $last_commit) = svn_grab_base_rev();
        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 $!;
                read_uuid();
                # looks like a user manually cp'd and svn switch'ed
                unless ($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)) {
                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;
        }
        close $svn_log->{fh};
        $last->{commit} = $last_commit;
        return $last;
}

sub fetch_lib {
        my (@parents) = @_;
        $SVN_URL ||= file_to_s("$GIT_SVN_DIR/info/url");
        $SVN ||= libsvn_connect($SVN_URL);
        my ($last_rev, $last_commit) = svn_grab_base_rev();
        my ($base, $head) = libsvn_parse_revision($last_rev);
        if ($base > $head) {
                return { revision => $last_rev, commit => $last_commit }
        }
        my $index = set_index($GIT_SVN_INDEX);

        # limit ourselves and also fork() since get_log won't release memory
        # after processing a revision and SVN stuff seems to leak
        my $inc = 1000;
        my ($min, $max) = ($base, $head < $base+$inc ? $head : $base+$inc);
        read_uuid();
        if (defined $last_commit) {
                unless (-e $GIT_SVN_INDEX) {
                        sys(qw/git-read-tree/, $last_commit);
                }
                chomp (my $x = `git-write-tree`);
                my ($y) = (`git-cat-file commit $last_commit`
                                                        =~ /^tree ($sha1)/m);
                if ($y ne $x) {
                        unlink $GIT_SVN_INDEX or croak $!;
                        sys(qw/git-read-tree/, $last_commit);
                }
                chomp ($x = `git-write-tree`);
                if ($y ne $x) {
                        print STDERR "trees ($last_commit) $y != $x\n",
                                 "Something is seriously wrong...\n";
                }
        }
        while (1) {
                # fork, because using SVN::Pool with get_log() still doesn't
                # seem to help enough to keep memory usage down.
                defined(my $pid = fork) or croak $!;
                if (!$pid) {
                        $SVN::Error::handler = \&libsvn_skip_unknown_revs;

                        # Yes I'm perfectly aware that the fourth argument
                        # below is the limit revisions number.  Unfortunately
                        # performance sucks with it enabled, so it's much
                        # faster to fetch revision ranges instead of relying
                        # on the limiter.
                        libsvn_get_log(libsvn_dup_ra($SVN), [''],
                                        $min, $max, 0, 1, 1,
                                sub {
                                        my $log_msg;
                                        if ($last_commit) {
                                                $log_msg = libsvn_fetch(
                                                        $last_commit, @_);
                                                $last_commit = git_commit(
                                                        $log_msg,
                                                        $last_commit,
                                                        @parents);
                                        } else {
                                                $log_msg = libsvn_new_tree(@_);
                                                $last_commit = git_commit(
                                                        $log_msg, @parents);
                                        }
                                });
                        exit 0;
                }
                waitpid $pid, 0;
                croak $? if $?;
                ($last_rev, $last_commit) = svn_grab_base_rev();
                last if ($max >= $head);
                $min = $max + 1;
                $max += $inc;
                $max = $head if ($max > $head);
        }
        restore_index($index);
        return { revision => $last_rev, commit => $last_commit };
}

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;
        $_use_lib ? commit_lib(@revs) : commit_cmd(@revs);
        print "Done committing ",scalar @revs," revisions to SVN\n";
}

sub commit_cmd {
        my (@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 $last = $fetched;
        foreach my $c (@revs) {
                my $mods = svn_checkout_tree($last, $c);
                if (scalar @$mods == 0) {
                        print "Skipping, no changes detected\n";
                        next;
                }
                $last = svn_commit_tree($last, $c);
        }
}

sub commit_lib {
        my (@revs) = @_;
        my ($r_last, $cmt_last) = svn_grab_base_rev();
        defined $r_last or die "Must have an existing revision to commit\n";
        my $fetched = fetch();
        if ($r_last != $fetched->{revision}) {
                print STDERR "There are new revisions that were fetched ",
                                "and need to be merged (or acknowledged) ",
                                "before committing.\n",
                                "last rev: $r_last\n",
                                " current: $fetched->{revision}\n";
                exit 1;
        }
        read_uuid();
        my @lock = $SVN::Core::VERSION ge '1.2.0' ? (undef, 0) : ();
        my $commit_msg = "$GIT_SVN_DIR/.svn-commit.tmp.$$";

        my $repo;
        set_svn_commit_env();
        foreach my $c (@revs) {
                my $log_msg = get_commit_message($c, $commit_msg);

                # fork for each commit because there's a memory leak I
                # can't track down... (it's probably in the SVN code)
                defined(my $pid = open my $fh, '-|') or croak $!;
                if (!$pid) {
                        my $ed = SVN::Git::Editor->new(
                                        {       r => $r_last,
                                                ra => libsvn_dup_ra($SVN),
                                                c => $c,
                                                svn_path => $SVN->{svn_path},
                                        },
                                        $SVN->get_commit_editor(
                                                $log_msg->{msg},
                                                sub {
                                                        libsvn_commit_cb(
                                                                @_, $c,
                                                                $log_msg->{msg},
                                                                $r_last,
                                                                $cmt_last)
                                                },
                                                @lock)
                                        );
                        my $mods = libsvn_checkout_tree($cmt_last, $c, $ed);
                        if (@$mods == 0) {
                                print "No changes\nr$r_last = $cmt_last\n";
                                $ed->abort_edit;
                        } else {
                                $ed->close_edit;
                        }
                        exit 0;
                }
                my ($r_new, $cmt_new, $no);
                while (<$fh>) {
                        print $_;
                        chomp;
                        if (/^r(\d+) = ($sha1)$/o) {
                                ($r_new, $cmt_new) = ($1, $2);
                        } elsif ($_ eq 'No changes') {
                                $no = 1;
                        }
                }
                close $fh or exit 1;
                if (! defined $r_new && ! defined $cmt_new) {
                        unless ($no) {
                                die "Failed to parse revision information\n";
                        }
                } else {
                        ($r_last, $cmt_last) = ($r_new, $cmt_new);
                }
        }
        $ENV{LC_ALL} = 'C';
        unlink $commit_msg;
}

sub dcommit {
        my $gs = "refs/remotes/$GIT_SVN";
        chomp(my @refs = safe_qx(qw/git-rev-list --no-merges/, "$gs..HEAD"));
        my $last_rev;
        foreach my $d (reverse @refs) {
                if (quiet_run('git-rev-parse','--verify',"$d~1") != 0) {
                        die "Commit $d\n",
                            "has no parent commit, and therefore ",
                            "nothing to diff against.\n",
                            "You should be working from a repository ",
                            "originally created by git-svn\n";
                }
                unless (defined $last_rev) {
                        (undef, $last_rev, undef) = cmt_metadata("$d~1");
                        unless (defined $last_rev) {
                                die "Unable to extract revision information ",
                                    "from commit $d~1\n";
                        }
                }
                if ($_dry_run) {
                        print "diff-tree $d~1 $d\n";
                } else {
                        if (my $r = commit_diff("$d~1", $d, undef, $last_rev)) {
                                $last_rev = $r;
                        } # else: no changes, same $last_rev
                }
        }
        return if $_dry_run;
        fetch();
        my @diff = safe_qx(qw/git-diff-tree HEAD/, $gs);
        my @finish;
        if (@diff) {
                @finish = qw/rebase/;
                push @finish, qw/--merge/ if $_merge;
                push @finish, "--strategy=$_strategy" if $_strategy;
                print STDERR "W: HEAD and $gs differ, using @finish:\n", @diff;
        } else {
                print "No changes between current HEAD and $gs\n",
                      "Hard resetting to the latest $gs\n";
                @finish = qw/reset --mixed/;
        }
        sys('git', @finish, $gs);
}

sub show_ignore {
        $SVN_URL ||= file_to_s("$GIT_SVN_DIR/info/url");
        $_use_lib ? show_ignore_lib() : show_ignore_cmd();
}

sub show_ignore_cmd {
        require File::Find or die $!;
        if (defined $_revision) {
                die "-r/--revision option doesn't work unless the Perl SVN ",
                        "libraries are used\n";
        }
        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 show_ignore_lib {
        my $repo;
        $SVN ||= libsvn_connect($SVN_URL);
        my $r = defined $_revision ? $_revision : $SVN->get_latest_revnum;
        libsvn_traverse_ignore(\*STDOUT, $SVN->{svn_path}, $r);
}

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+with\s+([\w\.\-]+)/i,
                        qr/\b(?:merge|merging|merged)\s+([\w\.\-]+)/i,
                        qr/\b(?:from|of)\s+([\w\.\-]+)/i );
        }
        foreach my $u (keys %$l_map) {
                if (@re) {
                        foreach my $p (keys %{$l_map->{$u}}) {
                                graft_merge_msg($grafts,$l_map,$u,$p,@re);
                        }
                }
                unless ($_no_graft_copy) {
                        if ($_use_lib) {
                                graft_file_copy_lib($grafts,$l_map,$u);
                        } else {
                                graft_file_copy_cmd($grafts,$l_map,$u);
                        }
                }
        }
        graft_tree_joins($grafts);

        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;
        }
        my $ch_id;
        if ($GIT_SVN eq 'git-svn') {
                $ch_id = 1;
                $GIT_SVN = $ENV{GIT_SVN_ID} = 'trunk';
        }
        init_vars();
        unless (-d $GIT_SVN_DIR) {
                print "GIT_SVN_ID set to 'trunk' for $_trunk\n" if $ch_id;
                init($_trunk);
                sys('git-repo-config', 'svn.trunk', $_trunk);
        }
        complete_url_ls_init($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 (-e "$GIT_DIR/svn/trunk/info/url") {
                fetch_child_id('trunk', @_);
        }
        rec_fetch('', "$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;
                }
        }

        config_pager();
        my $pid = open(my $log,'-|');
        defined $pid or croak $!;
        if (!$pid) {
                exec(git_svn_log_cmd($r_min,$r_max), @args) or croak $!;
        }
        run_pager();
        my (@k, $c, $d);

        while (<$log>) {
                if (/^${_esc_color}commit ($sha1_short)/o) {
                        my $cmt = $1;
                        if ($c && cmt_showable($c) && $c->{r} != $r_last) {
                                $r_last = $c->{r};
                                process_commit($c, $r_min, $r_max, \@k) or
                                                                goto out;
                        }
                        $d = undef;
                        $c = { c => $cmt };
                } elsif (/^${_esc_color}author (.+) (\d+) ([\-\+]?\d+)$/) {
                        get_author_info($c, $1, $2, $3);
                } elsif (/^${_esc_color}(?:tree|parent|committer) /) {
                        # ignore
                } elsif (/^${_esc_color}:\d{6} \d{6} $sha1_short/o) {
                        push @{$c->{raw}}, $_;
                } elsif (/^${_esc_color}[ACRMDT]\t/) {
                        # we could add $SVN->{svn_path} here, but that requires
                        # remote access at the moment (repo_path_split)...
                        s#^(${_esc_color})([ACRMDT])\t#$1   $2 #;
                        push @{$c->{changed}}, $_;
                } elsif (/^${_esc_color}diff /) {
                        $d = 1;
                        push @{$c->{diff}}, $_;
                } elsif ($d) {
                        push @{$c->{diff}}, $_;
                } elsif (/^${_esc_color}    (git-svn-id:.+)$/) {
                        ($c->{url}, $c->{r}, undef) = extract_metadata($1);
                } elsif (s/^${_esc_color}    //) {
                        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;
}

sub commit_diff_usage {
        print STDERR "Usage: $0 commit-diff <tree-ish> <tree-ish> [<URL>]\n";
        exit 1
}

sub commit_diff {
        if (!$_use_lib) {
                print STDERR "commit-diff must be used with SVN libraries\n";
                exit 1;
        }
        my $ta = shift or commit_diff_usage();
        my $tb = shift or commit_diff_usage();
        if (!eval { $SVN_URL = shift || file_to_s("$GIT_SVN_DIR/info/url") }) {
                print STDERR "Needed URL or usable git-svn id command-line\n";
                commit_diff_usage();
        }
        my $r = shift;
        unless (defined $r) {
                if (defined $_revision) {
                        $r = $_revision
                } else {
                        die "-r|--revision is a required argument\n";
                }
        }
        if (defined $_message && defined $_file) {
                print STDERR "Both --message/-m and --file/-F specified ",
                                "for the commit message.\n",
                                "I have no idea what you mean\n";
                exit 1;
        }
        if (defined $_file) {
                $_message = file_to_s($_file);
        } else {
                $_message ||= get_commit_message($tb,
                                        "$GIT_DIR/.svn-commit.tmp.$$")->{msg};
        }
        $SVN ||= libsvn_connect($SVN_URL);
        if ($r eq 'HEAD') {
                $r = $SVN->get_latest_revnum;
        } elsif ($r !~ /^\d+$/) {
                die "revision argument: $r not understood by git-svn\n";
        }
        my @lock = $SVN::Core::VERSION ge '1.2.0' ? (undef, 0) : ();
        my $rev_committed;
        my $ed = SVN::Git::Editor->new({        r => $r,
                                                ra => libsvn_dup_ra($SVN),
                                                c => $tb,
                                                svn_path => $SVN->{svn_path}
                                        },
                                $SVN->get_commit_editor($_message,
                                        sub {
                                                $rev_committed = $_[0];
                                                print "Committed $_[0]\n";
                                        }, @lock)
                                );
        eval {
                my $mods = libsvn_checkout_tree($ta, $tb, $ed);
                if (@$mods == 0) {
                        print "No changes\n$ta == $tb\n";
                        $ed->abort_edit;
                } else {
                        $ed->close_edit;
                }
        };
        fatal "$@\n" if $@;
        $_message = $_file = undef;
        return $rev_committed;
}

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

sub cmt_showable {
        my ($c) = @_;
        return 1 if defined $c->{r};
        if ($c->{l} && $c->{l}->[-1] eq "...\n" &&
                                $c->{a_raw} =~ /\@([a-f\d\-]+)>$/) {
                my @msg = safe_qx(qw/git-cat-file commit/, $c->{c});
                shift @msg while ($msg[0] ne "\n");
                shift @msg;
                @{$c->{l}} = grep !/^git-svn-id: /, @msg;

                (undef, $c->{r}, undef) = extract_metadata(
                                (grep(/^git-svn-id: /, @msg))[-1]);
        }
        return defined $c->{r};
}

sub log_use_color {
        return 1 if $_color;
        my $dc;
        chomp($dc = `git-repo-config --get diff.color`);
        if ($dc eq 'auto') {
                if (-t *STDOUT || (defined $_pager &&
                    `git-repo-config --bool --get pager.color` !~ /^false/)) {
                        return ($ENV{TERM} && $ENV{TERM} ne 'dumb');
                }
                return 0;
        }
        return 0 if $dc eq 'never';
        return 1 if $dc eq 'always';
        chomp($dc = `git-repo-config --bool --get diff.color`);
        $dc eq 'true';
}

sub git_svn_log_cmd {
        my ($r_min, $r_max) = @_;
        my @cmd = (qw/git-log --abbrev-commit --pretty=raw
                        --default/, "refs/remotes/$GIT_SVN");
        push @cmd, '-r' unless $_non_recursive;
        push @cmd, qw/--raw --name-status/ if $_verbose;
        push @cmd, '--color' if log_use_color();
        return @cmd unless defined $r_max;
        if ($r_max == $r_min) {
                push @cmd, '--max-count=1';
                if (my $c = revdb_get($REVDB, $r_max)) {
                        push @cmd, $c;
                }
        } else {
                my ($c_min, $c_max);
                $c_max = revdb_get($REVDB, $r_max);
                $c_min = revdb_get($REVDB, $r_min);
                if (defined $c_min && defined $c_max) {
                        if ($r_max > $r_max) {
                                push @cmd, "$c_min..$c_max";
                        } else {
                                push @cmd, "$c_max..$c_min";
                        }
                } elsif ($r_max > $r_min) {
                        push @cmd, $c_max;
                } else {
                        push @cmd, $c_min;
                }
        }
        return @cmd;
}

sub fetch_child_id {
        my $id = shift;
        print "Fetching $id\n";
        my $ref = "$GIT_DIR/refs/remotes/$id";
        defined(my $pid = open my $fh, '-|') or croak $!;
        if (!$pid) {
                $_repack = undef;
                $GIT_SVN = $ENV{GIT_SVN_ID} = $id;
                init_vars();
                fetch(@_);
                exit 0;
        }
        while (<$fh>) {
                print $_;
                check_repack() if (/^r\d+ = $sha1/);
        }
        close $fh or croak $?;
}

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 $id eq 'trunk';
                        fetch_child_id($id, @args);
                } 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 = $_use_lib ? libsvn_ls_fullurl($var)
                                : 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";
                        }
                        # don't try to init already existing refs
                        my $id = $pfx.$1;
                        $GIT_SVN = $ENV{GIT_SVN_ID} = $id;
                        init_vars();
                        unless (-d $GIT_SVN_DIR) {
                                print "init $u => $id\n";
                                init($u);
                        }
                }
                exit 0;
        }
        waitpid $pid, 0;
        croak $? if $?;
        my ($n) = ($switch =~ /^--(\w+)/);
        sys('git-repo-config', "svn.$n", $var);
}

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 '';
}

# grafts set here are 'stronger' in that they're based on actual tree
# matches, and won't be deleted from merge-base checking in write_grafts()
sub graft_tree_joins {
        my $grafts = shift;
        map_tree_joins() if (@_branch_from && !%tree_map);
        return unless %tree_map;

        git_svn_each(sub {
                my $i = shift;
                defined(my $pid = open my $fh, '-|') or croak $!;
                if (!$pid) {
                        exec qw/git-rev-list --pretty=raw/,
                                        "refs/remotes/$i" or croak $!;
                }
                while (<$fh>) {
                        next unless /^commit ($sha1)$/o;
                        my $c = $1;
                        my ($t) = (<$fh> =~ /^tree ($sha1)$/o);
                        next unless $tree_map{$t};

                        my $l;
                        do {
                                $l = readline $fh;
                        } until ($l =~ /^committer (?:.+) (\d+) ([\-\+]?\d+)$/);

                        my ($s, $tz) = ($1, $2);
                        if ($tz =~ s/^\+//) {
                                $s += tz_to_s_offset($tz);
                        } elsif ($tz =~ s/^\-//) {
                                $s -= tz_to_s_offset($tz);
                        }

                        my ($url_a, $r_a, $uuid_a) = cmt_metadata($c);

                        foreach my $p (@{$tree_map{$t}}) {
                                next if $p eq $c;
                                my $mb = eval {
                                        safe_qx('git-merge-base', $c, $p)
                                };
                                next unless ($@ || $?);
                                if (defined $r_a) {
                                        # see if SVN says it's a relative
                                        my ($url_b, $r_b, $uuid_b) =
                                                        cmt_metadata($p);
                                        next if (defined $url_b &&
                                                        defined $url_a &&
                                                        ($url_a eq $url_b) &&
                                                        ($uuid_a eq $uuid_b));
                                        if ($uuid_a eq $uuid_b) {
                                                if ($r_b < $r_a) {
                                                        $grafts->{$c}->{$p} = 2;
                                                        next;
                                                } elsif ($r_b > $r_a) {
                                                        $grafts->{$p}->{$c} = 2;
                                                        next;
                                                }
                                        }
                                }
                                my $ct = get_commit_time($p);
                                if ($ct < $s) {
                                        $grafts->{$c}->{$p} = 2;
                                } elsif ($ct > $s) {
                                        $grafts->{$p}->{$c} = 2;
                                }
                                # what should we do when $ct == $s ?
                        }
                }
                close $fh or croak $?;
        });
}

# this isn't funky-filename safe, but good enough for now...
sub graft_file_copy_cmd {
        my ($grafts, $l_map, $u) = @_;
        my $paths = $l_map->{$u};
        my $pfx = common_prefix([keys %$paths]);
        $SVN_URL ||= $u.$pfx;
        my $pid = open my $fh, '-|';
        defined $pid or croak $!;
        unless ($pid) {
                my @exec = qw/svn log -v/;
                push @exec, "-r$_revision" if defined $_revision;
                exec @exec, $u.$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.*?) \(from /(\S+?):(\d+)\)$#) {
                        my ($p1, $p0, $r0) = ($1, $2, $3);
                        my $c = find_graft_path_commit($paths, $p1, $r);
                        next unless $c;
                        find_graft_path_parents($grafts, $paths, $c, $p0, $r0);
                }
        }
}

sub graft_file_copy_lib {
        my ($grafts, $l_map, $u) = @_;
        my $tree_paths = $l_map->{$u};
        my $pfx = common_prefix([keys %$tree_paths]);
        my ($repo, $path) = repo_path_split($u.$pfx);
        $SVN = libsvn_connect($repo);

        my ($base, $head) = libsvn_parse_revision();
        my $inc = 1000;
        my ($min, $max) = ($base, $head < $base+$inc ? $head : $base+$inc);
        my $eh = $SVN::Error::handler;
        $SVN::Error::handler = \&libsvn_skip_unknown_revs;
        while (1) {
                my $pool = SVN::Pool->new;
                libsvn_get_log(libsvn_dup_ra($SVN), [$path],
                               $min, $max, 0, 2, 1,
                        sub {
                                libsvn_graft_file_copies($grafts, $tree_paths,
                                                        $path, @_);
                        }, $pool);
                $pool->clear;
                last if ($max >= $head);
                $min = $max + 1;
                $max += $inc;
                $max = $head if ($max > $head);
        }
        $SVN::Error::handler = $eh;
}

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, $l_map->{$u}->{$_};
                                last;
                        }
                }
                last if @strong;
                $w = basename($w);
                $re = qr/\Q$w\E/i;
                foreach (keys %{$l_map->{$u}}) {
                        if (/$re/) {
                                push @strong, $l_map->{$u}->{$_};
                                last;
                        }
                }
        }
        my ($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, 1);
                $grafts->{$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 $SVN_UUID;
        if ($_use_lib) {
                my $pool = SVN::Pool->new;
                $SVN_UUID = $SVN->get_uuid($pool);
                $pool->clear;
        } else {
                my $info = shift || svn_info('.');
                $SVN_UUID = $info->{'Repository UUID'} or
                                        croak "Repository UUID unreadable\n";
        }
}

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, $full_url);
                }
        }
        if ($_use_lib) {
                my $tmp = libsvn_connect($full_url);
                return ($tmp->{repos_root}, $tmp->{svn_path});
        } else {
                my ($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"]);
        open my $fh, '>>',$REVDB or croak $!;
        close $fh;
        s_to_file($SVN_URL,"$GIT_SVN_DIR/info/url");

}

sub assert_svn_wc_clean {
        return if $_use_lib;
        my ($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);
        @status = grep(!/^X/,@status) if $_no_ignore_ext;
        if (scalar @status) {
                print STDERR "Tree ($SVN_WC) is not clean:\n";
                print STDERR $_ foreach @status;
                croak;
        }
}

sub get_tree_from_treeish {
        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";
        }
        return $expected;
}

sub assert_tree {
        return if $_use_lib;
        my ($treeish) = @_;
        my $expected = get_tree_from_treeish($treeish);

        my $tmpindex = $GIT_SVN_INDEX.'.assert-tmp';
        if (-e $tmpindex) {
                unlink $tmpindex or croak $!;
        }
        my $old_index = set_index($tmpindex);
        index_changes(1);
        chomp(my $tree = `git-write-tree`);
        restore_index($old_index);
        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 get_diff {
        my ($from, $treeish) = @_;
        assert_tree($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 $!;
        }
        return parse_diff_tree($diff_fh);
}

sub svn_checkout_tree {
        my ($from, $treeish) = @_;
        my $mods = get_diff($from->{commit}, $treeish);
        return $mods unless (scalar @$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 ($m->{chg} eq 'T') {
                        svn_check_prop_executable($m);
                        apply_mod_line_blob($m);
                        if ($m->{mode_a} =~ /^120/ && $m->{mode_b} !~ /^120/) {
                                sys(qw(svn propdel svn:special), $m->{file_b});
                        } else {
                                sys(qw(svn propset svn:special *),$m->{file_b});
                        }
                } elsif ($m->{chg} eq 'A') {
                        svn_ensure_parent_path( $m->{file_b} );
                        apply_mod_line_blob($m);
                        sys(qw(svn add), $m->{file_b});
                        svn_check_prop_executable($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;
}

sub libsvn_checkout_tree {
        my ($from, $treeish, $ed) = @_;
        my $mods = get_diff($from, $treeish);
        return $mods unless (scalar @$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) {
                my $f = $m->{chg};
                if (defined $o{$f}) {
                        $ed->$f($m, $_q);
                } else {
                        croak "Invalid change type: $f\n";
                }
        }
        $ed->rmdirs($_q) if $_rmdir;
        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 get_commit_message {
        my ($commit, $commit_msg) = (@_);
        my %log_msg = ( msg => '' );
        open my $msg, '>', $commit_msg or croak $!;

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

                if ($pid == 0) {
                        exec('git-cat-file', $type, $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 $!;

        return \%log_msg;
}

sub set_svn_commit_env {
        if (defined $LC_ALL) {
                $ENV{LC_ALL} = $LC_ALL;
        } else {
                delete $ENV{LC_ALL};
        }
}

sub svn_commit_tree {
        my ($last, $commit) = @_;
        my $commit_msg = "$GIT_SVN_DIR/.svn-commit.tmp.$$";
        my $log_msg = get_commit_message($commit, $commit_msg);
        my ($oneline) = ($log_msg->{msg} =~ /([^\n\r]+)/);
        print "Committing $commit: $oneline\n";

        set_svn_commit_env();
        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 $_no_ignore_ext;
        if ($_optimize_commits && ($committed == ($last->{revision} + 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";
                $log_msg->{parents} = [ $last->{commit} ];
                $log_msg->{commit} = git_commit($log_msg, $commit);
                return $log_msg;
        }
        # resync immediately
        push @svn_up, "-r$last->{revision}";
        sys(@svn_up);
        return fetch("$committed=$commit");
}

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+)/);
                        $date = '1970-01-01 00:00:00 +0000'
                                if ($_ignore_nodate && $date eq '(no date)');
                        my ($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 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");
                                $tb =~ s#^/##;
                        }
                        my @s = stat($x);
                        unlink $x or croak $!;
                        copy($tb, $x);
                        chmod(($mode &~ umask), $x) or croak $!;
                        utime $s[8], $s[9], $x;
                }
                print $ui $x,"\0";
        }
        close $ui or croak $?;
}

sub index_changes {
        return if $_use_lib;

        if (!-f "$GIT_SVN_DIR/info/exclude") {
                open my $fd, '>>', "$GIT_SVN_DIR/info/exclude" or croak $!;
                print $fd '.svn',"\n";
                close $fd or croak $!;
        }
        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 $r = shift;
        if (my $c = revdb_get($REVDB, $r)) {
                croak "$r = $c 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 git_commit {
        my ($log_msg, @parents) = @_;
        assert_revision_unknown($log_msg->{revision});
        map_tree_joins() if (@_branch_from && !%tree_map);

        my (@tmp_parents, @exec_parents, %seen_parent);
        if (my $lparents = $log_msg->{parents}) {
                @tmp_parents = @$lparents
        }
        # commit parents can be conditionally bound to a particular
        # svn revision via: "svn_revno=commit_sha1", filter them out here:
        foreach my $p (@parents) {
                next unless defined $p;
                if ($p =~ /^(\d+)=($sha1_short)$/o) {
                        if ($1 == $log_msg->{revision}) {
                                push @tmp_parents, $2;
                        }
                } else {
                        push @tmp_parents, $p if $p =~ /$sha1_short/o;
                }
        }
        my $tree = $log_msg->{tree};
        if (!defined $tree) {
                my $index = set_index($GIT_SVN_INDEX);
                index_changes();
                chomp($tree = `git-write-tree`);
                croak $? if $?;
                restore_index($index);
        }

        # just in case we clobber the existing ref, we still want that ref
        # as our parent:
        if (my $cur = eval { file_to_s("$GIT_DIR/refs/remotes/$GIT_SVN") }) {
                push @tmp_parents, $cur;
        }

        if (exists $tree_map{$tree}) {
                foreach my $p (@{$tree_map{$tree}}) {
                        my $skip;
                        foreach (@tmp_parents) {
                                # see if a common parent is found
                                my $mb = eval {
                                        safe_qx('git-merge-base', $_, $p)
                                };
                                next if ($@ || $?);
                                $skip = 1;
                                last;
                        }
                        next if $skip;
                        my ($url_p, $r_p, $uuid_p) = cmt_metadata($p);
                        next if (($SVN_UUID eq $uuid_p) &&
                                                ($log_msg->{revision} > $r_p));
                        next if (defined $url_p && defined $SVN_URL &&
                                                ($SVN_UUID eq $uuid_p) &&
                                                ($url_p eq $SVN_URL));
                        push @tmp_parents, $p;
                }
        }
        foreach (@tmp_parents) {
                next if $seen_parent{$_};
                $seen_parent{$_} = 1;
                push @exec_parents, $_;
                # MAXPARENT is defined to 16 in commit-tree.c:
                last if @exec_parents > 16;
        }

        set_commit_env($log_msg);
        my @exec = ('git-commit-tree', $tree);
        push @exec, '-p', $_  foreach @exec_parents;
        defined(my $pid = open3(my $msg_fh, my $out_fh, '>&STDERR', @exec))
                                                                or croak $!;
        print $msg_fh $log_msg->{msg} or croak $!;
        unless ($_no_metadata) {
                print $msg_fh "\ngit-svn-id: $SVN_URL\@$log_msg->{revision}",
                                        " $SVN_UUID\n" or croak $!;
        }
        $msg_fh->flush == 0 or croak $!;
        close $msg_fh or croak $!;
        chomp(my $commit = do { local $/; <$out_fh> });
        close $out_fh or croak $!;
        waitpid $pid, 0;
        croak $? if $?;
        if ($commit !~ /^$sha1$/o) {
                die "Failed to commit, invalid sha1: $commit\n";
        }
        sys('git-update-ref',"refs/remotes/$GIT_SVN",$commit);
        revdb_set($REVDB, $log_msg->{revision}, $commit);

        # this output is read via pipe, do not change:
        print "r$log_msg->{revision} = $commit\n";
        check_repack();
        return $commit;
}

sub check_repack {
        if ($_repack && (--$_repack_nr == 0)) {
                $_repack_nr = $_repack;
                sys("git repack $_repack_flags");
        }
}

sub set_commit_env {
        my ($log_msg) = @_;
        my $author = $log_msg->{author};
        if (!defined $author || length $author == 0) {
                $author = '(no author)';
        }
        my ($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 {
        if ($_follow_parent) {
                print STDERR 'E: --follow-parent functionality is only ',
                                "available when SVN libraries are used\n";
                exit 1;
        }
        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 {
        if (!-r $REVDB) {
                -d $GIT_SVN_DIR or mkpath([$GIT_SVN_DIR]);
                open my $fh, '>>',$REVDB or croak $!;
                close $fh;
        }
        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+?|\(no author\))\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 migrate_revdb {
        git_svn_each(sub {
                my $id = shift;
                defined(my $pid = fork) or croak $!;
                if (!$pid) {
                        $GIT_SVN = $ENV{GIT_SVN_ID} = $id;
                        init_vars();
                        exit 0 if -r $REVDB;
                        print "Upgrading svn => git mapping...\n";
                        -d $GIT_SVN_DIR or mkpath([$GIT_SVN_DIR]);
                        open my $fh, '>>',$REVDB or croak $!;
                        close $fh;
                        rebuild();
                        print "Done upgrading. You may now delete the ",
                                "deprecated $GIT_SVN_DIR/revs directory\n";
                        exit 0;
                }
                waitpid $pid, 0;
                croak $? if $?;
        });
}

sub migration_check {
        migrate_revdb() unless (-e $REVDB);
        return if (-d "$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";
        }
        migrate_revdb() if (-d $GIT_SVN_DIR && !-w $REVDB);
        print "Done upgrading.\n";
}

sub find_rev_before {
        my ($r, $id, $eq_ok) = @_;
        my $f = "$GIT_DIR/svn/$id/.rev_db";
        return (undef,undef) unless -r $f;
        --$r unless $eq_ok;
        while ($r > 0) {
                if (my $c = revdb_get($f, $r)) {
                        return ($r, $c);
                }
                --$r;
        }
        return (undef, undef);
}

sub init_vars {
        $GIT_SVN ||= $ENV{GIT_SVN_ID} || 'git-svn';
        $GIT_SVN_DIR = "$GIT_DIR/svn/$GIT_SVN";
        $REVDB = "$GIT_SVN_DIR/.rev_db";
        $GIT_SVN_INDEX = "$GIT_SVN_DIR/index";
        $SVN_URL = undef;
        $SVN_WC = "$GIT_SVN_DIR/tree";
        %tree_map = ();
}

# 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 ||= '-d';
        }
}

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};
                my %x; # real parents
                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 ($sha1)/) {
                                $x{$1} = $p->{$1} = 1;
                        } else {
                                last unless /^\S/;
                        }
                }
                close $ch; # breaking the pipe

                # if real parents are the only ones in the grafts, drop it
                next if join(' ',sort keys %$p) eq join(' ',sort keys %x);

                my (@ip, @jp, $mb);
                my %del = %x;
                @ip = @jp = keys %$p;
                foreach my $i (@ip) {
                        next if $del{$i} || $p->{$i} == 2;
                        foreach my $j (@jp) {
                                next if $i eq $j || $del{$j} || $p->{$j} == 2;
                                $mb = eval { safe_qx('git-merge-base',$i,$j) };
                                next unless $mb;
                                chomp $mb;
                                next if $x{$mb};
                                if ($mb eq $j) {
                                        delete $p->{$i};
                                        $del{$i} = 1;
                                } elsif ($mb eq $i) {
                                        delete $p->{$j};
                                        $del{$j} = 1;
                                }
                        }
                }

                # if real parents are the only ones in the grafts, drop it
                next if join(' ',sort keys %$p) eq join(' ',sort keys %x);

                print $fh $c, ' ', join(' ', sort keys %$p),"\n";
        }
        if ($comments->{'END'}) {
                print $fh $_ foreach @{$comments->{'END'}};
        }
        close $fh or croak $!;
}

sub read_url_paths_all {
        my ($l_map, $pfx, $p) = @_;
        my @dir;
        foreach (<$p/*>) {
                if (-r "$_/info/url") {
                        $pfx .= '/' if $pfx && $pfx !~ m!/$!;
                        my $id = $pfx . basename $_;
                        my $url = file_to_s("$_/info/url");
                        my ($u, $p) = repo_path_split($url);
                        $l_map->{$u}->{$p} = $id;
                } elsif (-d $_) {
                        push @dir, $_;
                }
        }
        foreach (@dir) {
                my $x = $_;
                $x =~ s!^\Q$GIT_DIR\E/svn/!!o;
                read_url_paths_all($l_map, $x, $_);
        }
}

# this one only gets ids that have been imported, not new ones
sub read_url_paths {
        my $l_map = {};
        git_svn_each(sub { my $x = shift;
                        my $url = file_to_s("$GIT_DIR/svn/$x/info/url");
                        my ($u, $p) = repo_path_split($url);
                        $l_map->{$u}->{$p} = $x;
                        });
        return $l_map;
}

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

sub cmt_metadata {
        return extract_metadata((grep(/^git-svn-id: /,
                safe_qx(qw/git-cat-file commit/, shift)))[-1]);
}

sub get_commit_time {
        my $cmt = shift;
        defined(my $pid = open my $fh, '-|') or croak $!;
        if (!$pid) {
                exec qw/git-rev-list --pretty=raw -n1/, $cmt or croak $!;
        }
        while (<$fh>) {
                /^committer\s(?:.+) (\d+) ([\-\+]?\d+)$/ or next;
                my ($s, $tz) = ($1, $2);
                if ($tz =~ s/^\+//) {
                        $s += tz_to_s_offset($tz);
                } elsif ($tz =~ s/^\-//) {
                        $s -= tz_to_s_offset($tz);
                }
                close $fh;
                return $s;
        }
        die "Can't get commit time for commit: $cmt\n";
}

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

# adapted from pager.c
sub config_pager {
        $_pager ||= $ENV{GIT_PAGER} || $ENV{PAGER};
        if (!defined $_pager) {
                $_pager = 'less';
        } elsif (length $_pager == 0 || $_pager eq 'cat') {
                $_pager = undef;
        }
}

sub run_pager {
        return unless -t *STDOUT;
        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} ||= 'FRSX';
        exec $_pager or croak "Can't run pager: $! ($_pager)\n";
}

sub get_author_info {
        my ($dest, $author, $t, $tz) = @_;
        $author =~ s/(?:^\s*|\s*$)//g;
        $dest->{a_raw} = $author;
        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_changed_paths {
        my ($c) = @_;
        return unless $c->{changed};
        print "Changed paths:\n", @{$c->{changed}};
}

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 > 0
                                          && $l->[($#$l - 1)] eq "\n") {
                        pop @$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 $nr_line, "\n";
                        show_commit_changed_paths($c);
                        print "\n";
                        print $_ foreach @$l;
                }
        } else {
                print "1 line\n";
                show_commit_changed_paths($c);
                print "\n";

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

sub libsvn_load {
        return unless $_use_lib;
        $_use_lib = eval {
                require SVN::Core;
                if ($SVN::Core::VERSION lt '1.1.0') {
                        die "Need SVN::Core 1.1.0 or better ",
                                        "(got $SVN::Core::VERSION) ",
                                        "Falling back to command-line svn\n";
                }
                require SVN::Ra;
                require SVN::Delta;
                push @SVN::Git::Editor::ISA, 'SVN::Delta::Editor';
                push @SVN::Git::Fetcher::ISA, 'SVN::Delta::Editor';
                *SVN::Git::Fetcher::process_rm = *process_rm;
                *SVN::Git::Fetcher::safe_qx = *safe_qx;
                my $kill_stupid_warnings = $SVN::Node::none.$SVN::Node::file.
                                        $SVN::Node::dir.$SVN::Node::unknown.
                                        $SVN::Node::none.$SVN::Node::file.
                                        $SVN::Node::dir.$SVN::Node::unknown.
                                        $SVN::Auth::SSL::CNMISMATCH.
                                        $SVN::Auth::SSL::NOTYETVALID.
                                        $SVN::Auth::SSL::EXPIRED.
                                        $SVN::Auth::SSL::UNKNOWNCA.
                                        $SVN::Auth::SSL::OTHER;
                1;
        };
}

sub _simple_prompt {
        my ($cred, $realm, $default_username, $may_save, $pool) = @_;
        $may_save = undef if $_no_auth_cache;
        $default_username = $_username if defined $_username;
        if (defined $default_username && length $default_username) {
                if (defined $realm && length $realm) {
                        print "Authentication realm: $realm\n";
                }
                $cred->username($default_username);
        } else {
                _username_prompt($cred, $realm, $may_save, $pool);
        }
        $cred->password(_read_password("Password for '" .
                                       $cred->username . "': ", $realm));
        $cred->may_save($may_save);
        $SVN::_Core::SVN_NO_ERROR;
}

sub _ssl_server_trust_prompt {
        my ($cred, $realm, $failures, $cert_info, $may_save, $pool) = @_;
        $may_save = undef if $_no_auth_cache;
        print "Error validating server certificate for '$realm':\n";
        if ($failures & $SVN::Auth::SSL::UNKNOWNCA) {
                print " - The certificate is not issued by a trusted ",
                      "authority. Use the\n",
                      "   fingerprint to validate the certificate manually!\n";
        }
        if ($failures & $SVN::Auth::SSL::CNMISMATCH) {
                print " - The certificate hostname does not match.\n";
        }
        if ($failures & $SVN::Auth::SSL::NOTYETVALID) {
                print " - The certificate is not yet valid.\n";
        }
        if ($failures & $SVN::Auth::SSL::EXPIRED) {
                print " - The certificate has expired.\n";
        }
        if ($failures & $SVN::Auth::SSL::OTHER) {
                print " - The certificate has an unknown error.\n";
        }
        printf( "Certificate information:\n".
                " - Hostname: %s\n".
                " - Valid: from %s until %s\n".
                " - Issuer: %s\n".
                " - Fingerprint: %s\n",
                map $cert_info->$_, qw(hostname valid_from valid_until
                                       issuer_dname fingerprint) );
        my $choice;
prompt:
        print $may_save ?
              "(R)eject, accept (t)emporarily or accept (p)ermanently? " :
              "(R)eject or accept (t)emporarily? ";
        $choice = lc(substr(<STDIN> || 'R', 0, 1));
        if ($choice =~ /^t$/i) {
                $cred->may_save(undef);
        } elsif ($choice =~ /^r$/i) {
                return -1;
        } elsif ($may_save && $choice =~ /^p$/i) {
                $cred->may_save($may_save);
        } else {
                goto prompt;
        }
        $cred->accepted_failures($failures);
        $SVN::_Core::SVN_NO_ERROR;
}

sub _ssl_client_cert_prompt {
        my ($cred, $realm, $may_save, $pool) = @_;
        $may_save = undef if $_no_auth_cache;
        print "Client certificate filename: ";
        chomp(my $filename = <STDIN>);
        $cred->cert_file($filename);
        $cred->may_save($may_save);
        $SVN::_Core::SVN_NO_ERROR;
}

sub _ssl_client_cert_pw_prompt {
        my ($cred, $realm, $may_save, $pool) = @_;
        $may_save = undef if $_no_auth_cache;
        $cred->password(_read_password("Password: ", $realm));
        $cred->may_save($may_save);
        $SVN::_Core::SVN_NO_ERROR;
}

sub _username_prompt {
        my ($cred, $realm, $may_save, $pool) = @_;
        $may_save = undef if $_no_auth_cache;
        if (defined $realm && length $realm) {
                print "Authentication realm: $realm\n";
        }
        my $username;
        if (defined $_username) {
                $username = $_username;
        } else {
                print "Username: ";
                chomp($username = <STDIN>);
        }
        $cred->username($username);
        $cred->may_save($may_save);
        $SVN::_Core::SVN_NO_ERROR;
}

sub _read_password {
        my ($prompt, $realm) = @_;
        print $prompt;
        require Term::ReadKey;
        Term::ReadKey::ReadMode('noecho');
        my $password = '';
        while (defined(my $key = Term::ReadKey::ReadKey(0))) {
                last if $key =~ /[\012\015]/; # \n\r
                $password .= $key;
        }
        Term::ReadKey::ReadMode('restore');
        print "\n";
        $password;
}

sub libsvn_connect {
        my ($url) = @_;
        SVN::_Core::svn_config_ensure($_config_dir, undef);
        my ($baton, $callbacks) = SVN::Core::auth_open_helper([
            SVN::Client::get_simple_provider(),
            SVN::Client::get_ssl_server_trust_file_provider(),
            SVN::Client::get_simple_prompt_provider(
              \&_simple_prompt, 2),
            SVN::Client::get_ssl_client_cert_prompt_provider(
              \&_ssl_client_cert_prompt, 2),
            SVN::Client::get_ssl_client_cert_pw_prompt_provider(
              \&_ssl_client_cert_pw_prompt, 2),
            SVN::Client::get_username_provider(),
            SVN::Client::get_ssl_server_trust_prompt_provider(
              \&_ssl_server_trust_prompt),
            SVN::Client::get_username_prompt_provider(
              \&_username_prompt, 2),
          ]);
        my $config = SVN::Core::config_get_config($_config_dir);
        my $ra = SVN::Ra->new(url => $url, auth => $baton,
                              config => $config,
                              pool => SVN::Pool->new,
                              auth_provider_callbacks => $callbacks);

        my $df = $ENV{GIT_SVN_DELTA_FETCH};
        if (defined $df) {
                $_xfer_delta = $df;
        } else {
                $_xfer_delta = ($url =~ m#^file://#) ? undef : 1;
        }
        $ra->{svn_path} = $url;
        $ra->{repos_root} = $ra->get_repos_root;
        $ra->{svn_path} =~ s#^\Q$ra->{repos_root}\E/*##;
        push @repo_path_split_cache, qr/^(\Q$ra->{repos_root}\E)/;
        return $ra;
}

sub libsvn_dup_ra {
        my ($ra) = @_;
        SVN::Ra->new(map { $_ => $ra->{$_} } qw/config url
                     auth auth_provider_callbacks repos_root svn_path/);
}

sub libsvn_get_file {
        my ($gui, $f, $rev, $chg) = @_;
        $f =~ s#^/##;
        print "\t$chg\t$f\n" unless $_q;

        my ($hash, $pid, $in, $out);
        my $pool = SVN::Pool->new;
        defined($pid = open3($in, $out, '>&STDERR',
                                qw/git-hash-object -w --stdin/)) or croak $!;
        # redirect STDOUT for SVN 1.1.x compatibility
        open my $stdout, '>&', \*STDOUT or croak $!;
        open STDOUT, '>&', $in or croak $!;
        my ($r, $props) = $SVN->get_file($f, $rev, \*STDOUT, $pool);
        $in->flush == 0 or croak $!;
        open STDOUT, '>&', $stdout or croak $!;
        close $in or croak $!;
        close $stdout or croak $!;
        $pool->clear;
        chomp($hash = do { local $/; <$out> });
        close $out or croak $!;
        waitpid $pid, 0;
        $hash =~ /^$sha1$/o or die "not a sha1: $hash\n";

        my $mode = exists $props->{'svn:executable'} ? '100755' : '100644';
        if (exists $props->{'svn:special'}) {
                $mode = '120000';
                my $link = `git-cat-file blob $hash`;
                $link =~ s/^link // or die "svn:special file with contents: <",
                                                $link, "> is not understood\n";
                defined($pid = open3($in, $out, '>&STDERR',
                                qw/git-hash-object -w --stdin/)) or croak $!;
                print $in $link;
                $in->flush == 0 or croak $!;
                close $in or croak $!;
                chomp($hash = do { local $/; <$out> });
                close $out or croak $!;
                waitpid $pid, 0;
                $hash =~ /^$sha1$/o or die "not a sha1: $hash\n";
        }
        print $gui $mode,' ',$hash,"\t",$f,"\0" or croak $!;
}

sub libsvn_log_entry {
        my ($rev, $author, $date, $msg, $parents) = @_;
        my ($Y,$m,$d,$H,$M,$S) = ($date =~ /^(\d{4})\-(\d\d)\-(\d\d)T
                                         (\d\d)\:(\d\d)\:(\d\d).\d+Z$/x)
                                or die "Unable to parse date: $date\n";
        if (defined $_authors && ! defined $users{$author}) {
                die "Author: $author not defined in $_authors file\n";
        }
        $msg = '' if ($rev == 0 && !defined $msg);
        return { revision => $rev, date => "+0000 $Y-$m-$d $H:$M:$S",
                author => $author, msg => $msg."\n", parents => $parents || [] }
}

sub process_rm {
        my ($gui, $last_commit, $f, $q) = @_;
        # remove entire directories.
        if (safe_qx('git-ls-tree',$last_commit,'--',$f) =~ /^040000 tree/) {
                defined(my $pid = open my $ls, '-|') or croak $!;
                if (!$pid) {
                        exec(qw/git-ls-tree -r --name-only -z/,
                                $last_commit,'--',$f) or croak $!;
                }
                local $/ = "\0";
                while (<$ls>) {
                        print $gui '0 ',0 x 40,"\t",$_ or croak $!;
                        print "\tD\t$_\n" unless $q;
                }
                print "\tD\t$f/\n" unless $q;
                close $ls or croak $?;
        } else {
                print $gui '0 ',0 x 40,"\t",$f,"\0" or croak $!;
                print "\tD\t$f\n" unless $q;
        }
}

sub libsvn_fetch {
        $_xfer_delta ? libsvn_fetch_delta(@_) : libsvn_fetch_full(@_);
}

sub libsvn_fetch_delta {
        my ($last_commit, $paths, $rev, $author, $date, $msg) = @_;
        my $pool = SVN::Pool->new;
        my $ed = SVN::Git::Fetcher->new({ c => $last_commit, q => $_q });
        my $reporter = $SVN->do_update($rev, '', 1, $ed, $pool);
        my @lock = $SVN::Core::VERSION ge '1.2.0' ? (undef) : ();
        my (undef, $last_rev, undef) = cmt_metadata($last_commit);
        $reporter->set_path('', $last_rev, 0, @lock, $pool);
        $reporter->finish_report($pool);
        $pool->clear;
        unless ($ed->{git_commit_ok}) {
                die "SVN connection failed somewhere...\n";
        }
        libsvn_log_entry($rev, $author, $date, $msg, [$last_commit]);
}

sub libsvn_fetch_full {
        my ($last_commit, $paths, $rev, $author, $date, $msg) = @_;
        open my $gui, '| git-update-index -z --index-info' or croak $!;
        my @amr;
        my $p = $SVN->{svn_path};
        foreach my $f (keys %$paths) {
                my $m = $paths->{$f}->action();
                if (length $p) {
                        $f =~ s#^/\Q$p\E/##;
                        next if $f =~ m#^/#;
                } else {
                        $f =~ s#^/##;
                }
                if ($m =~ /^[DR]$/) {
                        process_rm($gui, $last_commit, $f, $_q);
                        next if $m eq 'D';
                        # 'R' can be file replacements, too, right?
                }
                my $pool = SVN::Pool->new;
                my $t = $SVN->check_path($f, $rev, $pool);
                if ($t == $SVN::Node::file) {
                        if ($m =~ /^[AMR]$/) {
                                push @amr, [ $m, $f ];
                        } else {
                                die "Unrecognized action: $m, ($f r$rev)\n";
                        }
                } elsif ($t == $SVN::Node::dir && $m =~ /^[AR]$/) {
                        my @traversed = ();
                        libsvn_traverse($gui, '', $f, $rev, \@traversed);
                        foreach (@traversed) {
                                push @amr, [ $m, $_ ]
                        }
                }
                $pool->clear;
        }
        foreach (@amr) {
                libsvn_get_file($gui, $_->[1], $rev, $_->[0]);
        }
        close $gui or croak $?;
        return libsvn_log_entry($rev, $author, $date, $msg, [$last_commit]);
}

sub svn_grab_base_rev {
        defined(my $pid = open my $fh, '-|') or croak $!;
        if (!$pid) {
                open my $null, '>', '/dev/null' or croak $!;
                open STDERR, '>&', $null or croak $!;
                exec qw/git-rev-parse --verify/,"refs/remotes/$GIT_SVN^0"
                                                                or croak $!;
        }
        chomp(my $c = do { local $/; <$fh> });
        close $fh;
        if (defined $c && length $c) {
                my ($url, $rev, $uuid) = cmt_metadata($c);
                return ($rev, $c) if defined $rev;
        }
        if ($_no_metadata) {
                my $offset = -41; # from tail
                my $rl;
                open my $fh, '<', $REVDB or
                        die "--no-metadata specified and $REVDB not readable\n";
                seek $fh, $offset, 2;
                $rl = readline $fh;
                defined $rl or return (undef, undef);
                chomp $rl;
                while ($c ne $rl && tell $fh != 0) {
                        $offset -= 41;
                        seek $fh, $offset, 2;
                        $rl = readline $fh;
                        defined $rl or return (undef, undef);
                        chomp $rl;
                }
                my $rev = tell $fh;
                croak $! if ($rev < -1);
                $rev =  ($rev - 41) / 41;
                close $fh or croak $!;
                return ($rev, $c);
        }
        return (undef, undef);
}

sub libsvn_parse_revision {
        my $base = shift;
        my $head = $SVN->get_latest_revnum();
        if (!defined $_revision || $_revision eq 'BASE:HEAD') {
                return ($base + 1, $head) if (defined $base);
                return (0, $head);
        }
        return ($1, $2) if ($_revision =~ /^(\d+):(\d+)$/);
        return ($_revision, $_revision) if ($_revision =~ /^\d+$/);
        if ($_revision =~ /^BASE:(\d+)$/) {
                return ($base + 1, $1) if (defined $base);
                return (0, $head);
        }
        return ($1, $head) if ($_revision =~ /^(\d+):HEAD$/);
        die "revision argument: $_revision not understood by git-svn\n",
                "Try using the command-line svn client instead\n";
}

sub libsvn_traverse {
        my ($gui, $pfx, $path, $rev, $files) = @_;
        my $cwd = length $pfx ? "$pfx/$path" : $path;
        my $pool = SVN::Pool->new;
        $cwd =~ s#^\Q$SVN->{svn_path}\E##;
        my ($dirent, $r, $props) = $SVN->get_dir($cwd, $rev, $pool);
        foreach my $d (keys %$dirent) {
                my $t = $dirent->{$d}->kind;
                if ($t == $SVN::Node::dir) {
                        libsvn_traverse($gui, $cwd, $d, $rev, $files);
                } elsif ($t == $SVN::Node::file) {
                        my $file = "$cwd/$d";
                        if (defined $files) {
                                push @$files, $file;
                        } else {
                                libsvn_get_file($gui, $file, $rev, 'A');
                        }
                }
        }
        $pool->clear;
}

sub libsvn_traverse_ignore {
        my ($fh, $path, $r) = @_;
        $path =~ s#^/+##g;
        my $pool = SVN::Pool->new;
        my ($dirent, undef, $props) = $SVN->get_dir($path, $r, $pool);
        my $p = $path;
        $p =~ s#^\Q$SVN->{svn_path}\E/##;
        print $fh length $p ? "\n# $p\n" : "\n# /\n";
        if (my $s = $props->{'svn:ignore'}) {
                $s =~ s/[\r\n]+/\n/g;
                chomp $s;
                if (length $p == 0) {
                        $s =~ s#\n#\n/$p#g;
                        print $fh "/$s\n";
                } else {
                        $s =~ s#\n#\n/$p/#g;
                        print $fh "/$p/$s\n";
                }
        }
        foreach (sort keys %$dirent) {
                next if $dirent->{$_}->kind != $SVN::Node::dir;
                libsvn_traverse_ignore($fh, "$path/$_", $r);
        }
        $pool->clear;
}

sub revisions_eq {
        my ($path, $r0, $r1) = @_;
        return 1 if $r0 == $r1;
        my $nr = 0;
        if ($_use_lib) {
                # should be OK to use Pool here (r1 - r0) should be small
                my $pool = SVN::Pool->new;
                libsvn_get_log($SVN, [$path], $r0, $r1,
                                0, 0, 1, sub {$nr++}, $pool);
                $pool->clear;
        } else {
                my ($url, undef) = repo_path_split($SVN_URL);
                my $svn_log = svn_log_raw("$url/$path","-r$r0:$r1");
                while (next_log_entry($svn_log)) { $nr++ }
                close $svn_log->{fh};
        }
        return 0 if ($nr > 1);
        return 1;
}

sub libsvn_find_parent_branch {
        my ($paths, $rev, $author, $date, $msg) = @_;
        my $svn_path = '/'.$SVN->{svn_path};

        # look for a parent from another branch:
        my $i = $paths->{$svn_path} or return;
        my $branch_from = $i->copyfrom_path or return;
        my $r = $i->copyfrom_rev;
        print STDERR  "Found possible branch point: ",
                                "$branch_from => $svn_path, $r\n";
        $branch_from =~ s#^/##;
        my $l_map = {};
        read_url_paths_all($l_map, '', "$GIT_DIR/svn");
        my $url = $SVN->{repos_root};
        defined $l_map->{$url} or return;
        my $id = $l_map->{$url}->{$branch_from};
        if (!defined $id && $_follow_parent) {
                print STDERR "Following parent: $branch_from\@$r\n";
                # auto create a new branch and follow it
                $id = basename($branch_from);
                $id .= '@'.$r if -r "$GIT_DIR/svn/$id";
                while (-r "$GIT_DIR/svn/$id") {
                        # just grow a tail if we're not unique enough :x
                        $id .= '-';
                }
        }
        return unless defined $id;

        my ($r0, $parent) = find_rev_before($r,$id,1);
        if ($_follow_parent && (!defined $r0 || !defined $parent)) {
                defined(my $pid = fork) or croak $!;
                if (!$pid) {
                        $GIT_SVN = $ENV{GIT_SVN_ID} = $id;
                        init_vars();
                        $SVN_URL = "$url/$branch_from";
                        $SVN = undef;
                        setup_git_svn();
                        # we can't assume SVN_URL exists at r+1:
                        $_revision = "0:$r";
                        fetch_lib();
                        exit 0;
                }
                waitpid $pid, 0;
                croak $? if $?;
                ($r0, $parent) = find_rev_before($r,$id,1);
        }
        return unless (defined $r0 && defined $parent);
        if (revisions_eq($branch_from, $r0, $r)) {
                unlink $GIT_SVN_INDEX;
                print STDERR "Found branch parent: ($GIT_SVN) $parent\n";
                sys(qw/git-read-tree/, $parent);
                # I can't seem to get do_switch() to work correctly with
                # the SWIG interface (TypeError when passing switch_url...),
                # so we'll unconditionally bypass the delta interface here
                # for now
                return libsvn_fetch_full($parent, $paths, $rev,
                                        $author, $date, $msg);
        }
        print STDERR "Nope, branch point not imported or unknown\n";
        return undef;
}

sub libsvn_get_log {
        my ($ra, @args) = @_;
        $args[4]-- if $args[4] && $_xfer_delta && ! $_follow_parent;
        if ($SVN::Core::VERSION le '1.2.0') {
                splice(@args, 3, 1);
        }
        $ra->get_log(@args);
}

sub libsvn_new_tree {
        if (my $log_entry = libsvn_find_parent_branch(@_)) {
                return $log_entry;
        }
        my ($paths, $rev, $author, $date, $msg) = @_;
        if ($_xfer_delta) {
                my $pool = SVN::Pool->new;
                my $ed = SVN::Git::Fetcher->new({q => $_q});
                my $reporter = $SVN->do_update($rev, '', 1, $ed, $pool);
                my @lock = $SVN::Core::VERSION ge '1.2.0' ? (undef) : ();
                $reporter->set_path('', $rev, 1, @lock, $pool);
                $reporter->finish_report($pool);
                $pool->clear;
                unless ($ed->{git_commit_ok}) {
                        die "SVN connection failed somewhere...\n";
                }
        } else {
                open my $gui, '| git-update-index -z --index-info' or croak $!;
                libsvn_traverse($gui, '', $SVN->{svn_path}, $rev);
                close $gui or croak $?;
        }
        return libsvn_log_entry($rev, $author, $date, $msg);
}

sub find_graft_path_commit {
        my ($tree_paths, $p1, $r1) = @_;
        foreach my $x (keys %$tree_paths) {
                next unless ($p1 =~ /^\Q$x\E/);
                my $i = $tree_paths->{$x};
                my ($r0, $parent) = find_rev_before($r1,$i,1);
                return $parent if (defined $r0 && $r0 == $r1);
                print STDERR "r$r1 of $i not imported\n";
                next;
        }
        return undef;
}

sub find_graft_path_parents {
        my ($grafts, $tree_paths, $c, $p0, $r0) = @_;
        foreach my $x (keys %$tree_paths) {
                next unless ($p0 =~ /^\Q$x\E/);
                my $i = $tree_paths->{$x};
                my ($r, $parent) = find_rev_before($r0, $i, 1);
                if (defined $r && defined $parent && revisions_eq($x,$r,$r0)) {
                        my ($url_b, undef, $uuid_b) = cmt_metadata($c);
                        my ($url_a, undef, $uuid_a) = cmt_metadata($parent);
                        next if ($url_a && $url_b && $url_a eq $url_b &&
                                                        $uuid_b eq $uuid_a);
                        $grafts->{$c}->{$parent} = 1;
                }
        }
}

sub libsvn_graft_file_copies {
        my ($grafts, $tree_paths, $path, $paths, $rev) = @_;
        foreach (keys %$paths) {
                my $i = $paths->{$_};
                my ($m, $p0, $r0) = ($i->action, $i->copyfrom_path,
                                        $i->copyfrom_rev);
                next unless (defined $p0 && defined $r0);

                my $p1 = $_;
                $p1 =~ s#^/##;
                $p0 =~ s#^/##;
                my $c = find_graft_path_commit($tree_paths, $p1, $rev);
                next unless $c;
                find_graft_path_parents($grafts, $tree_paths, $c, $p0, $r0);
        }
}

sub set_index {
        my $old = $ENV{GIT_INDEX_FILE};
        $ENV{GIT_INDEX_FILE} = shift;
        return $old;
}

sub restore_index {
        my ($old) = @_;
        if (defined $old) {
                $ENV{GIT_INDEX_FILE} = $old;
        } else {
                delete $ENV{GIT_INDEX_FILE};
        }
}

sub libsvn_commit_cb {
        my ($rev, $date, $committer, $c, $msg, $r_last, $cmt_last) = @_;
        if ($_optimize_commits && $rev == ($r_last + 1)) {
                my $log = libsvn_log_entry($rev,$committer,$date,$msg);
                $log->{tree} = get_tree_from_treeish($c);
                my $cmt = git_commit($log, $cmt_last, $c);
                my @diff = safe_qx('git-diff-tree', $cmt, $c);
                if (@diff) {
                        print STDERR "Trees differ: $cmt $c\n",
                                        join('',@diff),"\n";
                        exit 1;
                }
        } else {
                fetch("$rev=$c");
        }
}

sub libsvn_ls_fullurl {
        my $fullurl = shift;
        $SVN ||= libsvn_connect($fullurl);
        my @ret;
        my $pool = SVN::Pool->new;
        my ($dirent, undef, undef) = $SVN->get_dir($SVN->{svn_path},
                                                $SVN->get_latest_revnum, $pool);
        foreach my $d (keys %$dirent) {
                if ($dirent->{$d}->kind == $SVN::Node::dir) {
                        push @ret, "$d/"; # add '/' for compat with cli svn
                }
        }
        $pool->clear;
        return @ret;
}


sub libsvn_skip_unknown_revs {
        my $err = shift;
        my $errno = $err->apr_err();
        # Maybe the branch we're tracking didn't
        # exist when the repo started, so it's
        # not an error if it doesn't, just continue
        #
        # Wonderfully consistent library, eh?
        # 160013 - svn:// and file://
        # 175002 - http(s)://
        # 175007 - http(s):// (this repo required authorization, too...)
        #   More codes may be discovered later...
        if ($errno == 175007 || $errno == 175002 || $errno == 160013) {
                return;
        }
        croak "Error from SVN, ($errno): ", $err->expanded_message,"\n";
};

# Tie::File seems to be prone to offset errors if revisions get sparse,
# it's not that fast, either.  Tie::File is also not in Perl 5.6.  So
# one of my favorite modules is out :<  Next up would be one of the DBM
# modules, but I'm not sure which is most portable...  So I'll just
# go with something that's plain-text, but still capable of
# being randomly accessed.  So here's my ultra-simple fixed-width
# database.  All records are 40 characters + "\n", so it's easy to seek
# to a revision: (41 * rev) is the byte offset.
# A record of 40 0s denotes an empty revision.
# And yes, it's still pretty fast (faster than Tie::File).
sub revdb_set {
        my ($file, $rev, $commit) = @_;
        length $commit == 40 or croak "arg3 must be a full SHA1 hexsum\n";
        open my $fh, '+<', $file or croak $!;
        my $offset = $rev * 41;
        # assume that append is the common case:
        seek $fh, 0, 2 or croak $!;
        my $pos = tell $fh;
        if ($pos < $offset) {
                print $fh (('0' x 40),"\n") x (($offset - $pos) / 41);
        }
        seek $fh, $offset, 0 or croak $!;
        print $fh $commit,"\n";
        close $fh or croak $!;
}

sub revdb_get {
        my ($file, $rev) = @_;
        my $ret;
        my $offset = $rev * 41;
        open my $fh, '<', $file or croak $!;
        seek $fh, $offset, 0;
        if (tell $fh == $offset) {
                $ret = readline $fh;
                if (defined $ret) {
                        chomp $ret;
                        $ret = undef if ($ret =~ /^0{40}$/);
                }
        }
        close $fh or croak $!;
        return $ret;
}

sub copy_remote_ref {
        my $origin = $_cp_remote ? $_cp_remote : 'origin';
        my $ref = "refs/remotes/$GIT_SVN";
        if (safe_qx('git-ls-remote', $origin, $ref)) {
                sys(qw/git fetch/, $origin, "$ref:$ref");
        } elsif ($_cp_remote && !$_upgrade) {
                die "Unable to find remote reference: ",
                                "refs/remotes/$GIT_SVN on $origin\n";
        }
}
package SVN::Git::Fetcher;
use vars qw/@ISA/;
use strict;
use warnings;
use Carp qw/croak/;
use IO::File qw//;

# file baton members: path, mode_a, mode_b, pool, fh, blob, base
sub new {
        my ($class, $git_svn) = @_;
        my $self = SVN::Delta::Editor->new;
        bless $self, $class;
        open my $gui, '| git-update-index -z --index-info' or croak $!;
        $self->{gui} = $gui;
        $self->{c} = $git_svn->{c} if exists $git_svn->{c};
        $self->{q} = $git_svn->{q};
        require Digest::MD5;
        $self;
}

sub delete_entry {
        my ($self, $path, $rev, $pb) = @_;
        process_rm($self->{gui}, $self->{c}, $path, $self->{q});
        undef;
}

sub open_file {
        my ($self, $path, $pb, $rev) = @_;
        my ($mode, $blob) = (safe_qx('git-ls-tree',$self->{c},'--',$path)
                             =~ /^(\d{6}) blob ([a-f\d]{40})\t/);
        { path => $path, mode_a => $mode, mode_b => $mode, blob => $blob,
          pool => SVN::Pool->new, action => 'M' };
}

sub add_file {
        my ($self, $path, $pb, $cp_path, $cp_rev) = @_;
        { path => $path, mode_a => 100644, mode_b => 100644,
          pool => SVN::Pool->new, action => 'A' };
}

sub change_file_prop {
        my ($self, $fb, $prop, $value) = @_;
        if ($prop eq 'svn:executable') {
                if ($fb->{mode_b} != 120000) {
                        $fb->{mode_b} = defined $value ? 100755 : 100644;
                }
        } elsif ($prop eq 'svn:special') {
                $fb->{mode_b} = defined $value ? 120000 : 100644;
        }
        undef;
}

sub apply_textdelta {
        my ($self, $fb, $exp) = @_;
        my $fh = IO::File->new_tmpfile;
        $fh->autoflush(1);
        # $fh gets auto-closed() by SVN::TxDelta::apply(),
        # (but $base does not,) so dup() it for reading in close_file
        open my $dup, '<&', $fh or croak $!;
        my $base = IO::File->new_tmpfile;
        $base->autoflush(1);
        if ($fb->{blob}) {
                defined (my $pid = fork) or croak $!;
                if (!$pid) {
                        open STDOUT, '>&', $base or croak $!;
                        print STDOUT 'link ' if ($fb->{mode_a} == 120000);
                        exec qw/git-cat-file blob/, $fb->{blob} or croak $!;
                }
                waitpid $pid, 0;
                croak $? if $?;

                if (defined $exp) {
                        seek $base, 0, 0 or croak $!;
                        my $md5 = Digest::MD5->new;
                        $md5->addfile($base);
                        my $got = $md5->hexdigest;
                        die "Checksum mismatch: $fb->{path} $fb->{blob}\n",
                            "expected: $exp\n",
                            "     got: $got\n" if ($got ne $exp);
                }
        }
        seek $base, 0, 0 or croak $!;
        $fb->{fh} = $dup;
        $fb->{base} = $base;
        [ SVN::TxDelta::apply($base, $fh, undef, $fb->{path}, $fb->{pool}) ];
}

sub close_file {
        my ($self, $fb, $exp) = @_;
        my $hash;
        my $path = $fb->{path};
        if (my $fh = $fb->{fh}) {
                seek($fh, 0, 0) or croak $!;
                my $md5 = Digest::MD5->new;
                $md5->addfile($fh);
                my $got = $md5->hexdigest;
                die "Checksum mismatch: $path\n",
                    "expected: $exp\n    got: $got\n" if ($got ne $exp);
                seek($fh, 0, 0) or croak $!;
                if ($fb->{mode_b} == 120000) {
                        read($fh, my $buf, 5) == 5 or croak $!;
                        $buf eq 'link ' or die "$path has mode 120000",
                                               "but is not a link\n";
                }
                defined(my $pid = open my $out,'-|') or die "Can't fork: $!\n";
                if (!$pid) {
                        open STDIN, '<&', $fh or croak $!;
                        exec qw/git-hash-object -w --stdin/ or croak $!;
                }
                chomp($hash = do { local $/; <$out> });
                close $out or croak $!;
                close $fh or croak $!;
                $hash =~ /^[a-f\d]{40}$/ or die "not a sha1: $hash\n";
                close $fb->{base} or croak $!;
        } else {
                $hash = $fb->{blob} or die "no blob information\n";
        }
        $fb->{pool}->clear;
        my $gui = $self->{gui};
        print $gui "$fb->{mode_b} $hash\t$path\0" or croak $!;
        print "\t$fb->{action}\t$path\n" if $fb->{action} && ! $self->{q};
        undef;
}

sub abort_edit {
        my $self = shift;
        close $self->{gui};
        $self->SUPER::abort_edit(@_);
}

sub close_edit {
        my $self = shift;
        close $self->{gui} or croak $!;
        $self->{git_commit_ok} = 1;
        $self->SUPER::close_edit(@_);
}

package SVN::Git::Editor;
use vars qw/@ISA/;
use strict;
use warnings;
use Carp qw/croak/;
use IO::File;

sub new {
        my $class = shift;
        my $git_svn = shift;
        my $self = SVN::Delta::Editor->new(@_);
        bless $self, $class;
        foreach (qw/svn_path c r ra /) {
                die "$_ required!\n" unless (defined $git_svn->{$_});
                $self->{$_} = $git_svn->{$_};
        }
        $self->{pool} = SVN::Pool->new;
        $self->{bat} = { '' => $self->open_root($self->{r}, $self->{pool}) };
        $self->{rm} = { };
        require Digest::MD5;
        return $self;
}

sub split_path {
        return ($_[0] =~ m#^(.*?)/?([^/]+)$#);
}

sub repo_path {
        (defined $_[1] && length $_[1]) ? $_[1] : ''
}

sub url_path {
        my ($self, $path) = @_;
        $self->{ra}->{url} . '/' . $self->repo_path($path);
}

sub rmdirs {
        my ($self, $q) = @_;
        my $rm = $self->{rm};
        delete $rm->{''}; # we never delete the url we're tracking
        return unless %$rm;

        foreach (keys %$rm) {
                my @d = split m#/#, $_;
                my $c = shift @d;
                $rm->{$c} = 1;
                while (@d) {
                        $c .= '/' . shift @d;
                        $rm->{$c} = 1;
                }
        }
        delete $rm->{$self->{svn_path}};
        delete $rm->{''}; # we never delete the url we're tracking
        return unless %$rm;

        defined(my $pid = open my $fh,'-|') or croak $!;
        if (!$pid) {
                exec qw/git-ls-tree --name-only -r -z/, $self->{c} or croak $!;
        }
        local $/ = "\0";
        while (<$fh>) {
                chomp;
                my @dn = split m#/#, $_;
                while (pop @dn) {
                        delete $rm->{join '/', @dn};
                }
                unless (%$rm) {
                        close $fh;
                        return;
                }
        }
        close $fh;

        my ($r, $p, $bat) = ($self->{r}, $self->{pool}, $self->{bat});
        foreach my $d (sort { $b =~ tr#/#/# <=> $a =~ tr#/#/# } keys %$rm) {
                $self->close_directory($bat->{$d}, $p);
                my ($dn) = ($d =~ m#^(.*?)/?(?:[^/]+)$#);
                print "\tD+\t/$d/\n" unless $q;
                $self->SUPER::delete_entry($d, $r, $bat->{$dn}, $p);
                delete $bat->{$d};
        }
}

sub open_or_add_dir {
        my ($self, $full_path, $baton) = @_;
        my $p = SVN::Pool->new;
        my $t = $self->{ra}->check_path($full_path, $self->{r}, $p);
        $p->clear;
        if ($t == $SVN::Node::none) {
                return $self->add_directory($full_path, $baton,
                                                undef, -1, $self->{pool});
        } elsif ($t == $SVN::Node::dir) {
                return $self->open_directory($full_path, $baton,
                                                $self->{r}, $self->{pool});
        }
        print STDERR "$full_path already exists in repository at ",
                "r$self->{r} and it is not a directory (",
                ($t == $SVN::Node::file ? 'file' : 'unknown'),"/$t)\n";
        exit 1;
}

sub ensure_path {
        my ($self, $path) = @_;
        my $bat = $self->{bat};
        $path = $self->repo_path($path);
        return $bat->{''} unless (length $path);
        my @p = split m#/+#, $path;
        my $c = shift @p;
        $bat->{$c} ||= $self->open_or_add_dir($c, $bat->{''});
        while (@p) {
                my $c0 = $c;
                $c .= '/' . shift @p;
                $bat->{$c} ||= $self->open_or_add_dir($c, $bat->{$c0});
        }
        return $bat->{$c};
}

sub A {
        my ($self, $m, $q) = @_;
        my ($dir, $file) = split_path($m->{file_b});
        my $pbat = $self->ensure_path($dir);
        my $fbat = $self->add_file($self->repo_path($m->{file_b}), $pbat,
                                        undef, -1);
        print "\tA\t$m->{file_b}\n" unless $q;
        $self->chg_file($fbat, $m);
        $self->close_file($fbat,undef,$self->{pool});
}

sub C {
        my ($self, $m, $q) = @_;
        my ($dir, $file) = split_path($m->{file_b});
        my $pbat = $self->ensure_path($dir);
        my $fbat = $self->add_file($self->repo_path($m->{file_b}), $pbat,
                                $self->url_path($m->{file_a}), $self->{r});
        print "\tC\t$m->{file_a} => $m->{file_b}\n" unless $q;
        $self->chg_file($fbat, $m);
        $self->close_file($fbat,undef,$self->{pool});
}

sub delete_entry {
        my ($self, $path, $pbat) = @_;
        my $rpath = $self->repo_path($path);
        my ($dir, $file) = split_path($rpath);
        $self->{rm}->{$dir} = 1;
        $self->SUPER::delete_entry($rpath, $self->{r}, $pbat, $self->{pool});
}

sub R {
        my ($self, $m, $q) = @_;
        my ($dir, $file) = split_path($m->{file_b});
        my $pbat = $self->ensure_path($dir);
        my $fbat = $self->add_file($self->repo_path($m->{file_b}), $pbat,
                                $self->url_path($m->{file_a}), $self->{r});
        print "\tR\t$m->{file_a} => $m->{file_b}\n" unless $q;
        $self->chg_file($fbat, $m);
        $self->close_file($fbat,undef,$self->{pool});

        ($dir, $file) = split_path($m->{file_a});
        $pbat = $self->ensure_path($dir);
        $self->delete_entry($m->{file_a}, $pbat);
}

sub M {
        my ($self, $m, $q) = @_;
        my ($dir, $file) = split_path($m->{file_b});
        my $pbat = $self->ensure_path($dir);
        my $fbat = $self->open_file($self->repo_path($m->{file_b}),
                                $pbat,$self->{r},$self->{pool});
        print "\t$m->{chg}\t$m->{file_b}\n" unless $q;
        $self->chg_file($fbat, $m);
        $self->close_file($fbat,undef,$self->{pool});
}

sub T { shift->M(@_) }

sub change_file_prop {
        my ($self, $fbat, $pname, $pval) = @_;
        $self->SUPER::change_file_prop($fbat, $pname, $pval, $self->{pool});
}

sub chg_file {
        my ($self, $fbat, $m) = @_;
        if ($m->{mode_b} =~ /755$/ && $m->{mode_a} !~ /755$/) {
                $self->change_file_prop($fbat,'svn:executable','*');
        } elsif ($m->{mode_b} !~ /755$/ && $m->{mode_a} =~ /755$/) {
                $self->change_file_prop($fbat,'svn:executable',undef);
        }
        my $fh = IO::File->new_tmpfile or croak $!;
        if ($m->{mode_b} =~ /^120/) {
                print $fh 'link ' or croak $!;
                $self->change_file_prop($fbat,'svn:special','*');
        } elsif ($m->{mode_a} =~ /^120/ && $m->{mode_b} !~ /^120/) {
                $self->change_file_prop($fbat,'svn:special',undef);
        }
        defined(my $pid = fork) or croak $!;
        if (!$pid) {
                open STDOUT, '>&', $fh or croak $!;
                exec qw/git-cat-file blob/, $m->{sha1_b} or croak $!;
        }
        waitpid $pid, 0;
        croak $? if $?;
        $fh->flush == 0 or croak $!;
        seek $fh, 0, 0 or croak $!;

        my $md5 = Digest::MD5->new;
        $md5->addfile($fh) or croak $!;
        seek $fh, 0, 0 or croak $!;

        my $exp = $md5->hexdigest;
        my $pool = SVN::Pool->new;
        my $atd = $self->apply_textdelta($fbat, undef, $pool);
        my $got = SVN::TxDelta::send_stream($fh, @$atd, $pool);
        die "Checksum mismatch\nexpected: $exp\ngot: $got\n" if ($got ne $exp);
        $pool->clear;

        close $fh or croak $!;
}

sub D {
        my ($self, $m, $q) = @_;
        my ($dir, $file) = split_path($m->{file_b});
        my $pbat = $self->ensure_path($dir);
        print "\tD\t$m->{file_b}\n" unless $q;
        $self->delete_entry($m->{file_b}, $pbat);
}

sub close_edit {
        my ($self) = @_;
        my ($p,$bat) = ($self->{pool}, $self->{bat});
        foreach (sort { $b =~ tr#/#/# <=> $a =~ tr#/#/# } keys %$bat) {
                $self->close_directory($bat->{$_}, $p);
        }
        $self->SUPER::close_edit($p);
        $p->clear;
}

sub abort_edit {
        my ($self) = @_;
        $self->SUPER::abort_edit($self->{pool});
        $self->{pool}->clear;
}

__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)
}
;

# retval of read_url_paths{,_all}();
$l_map = {
        # repository root url
        'https://svn.musicpd.org' => {
                # repository path               # GIT_SVN_ID
                'mpd/trunk'             =>      'trunk',
                'mpd/tags/0.11.5'       =>      'tags/0.11.5',
        },
}

Notes:
        I don't trust the each() function on unless I created %hash myself
        because the internal iterator may not have started at base.