path: root/git-cvsexportcommit.perl

#!/usr/bin/perl -w

use strict;
use Getopt::Std;
use File::Temp qw(tempdir);
use Data::Dumper;
use File::Basename qw(basename dirname);
use File::Spec;
use Git;

our ($opt_h, $opt_P, $opt_p, $opt_v, $opt_c, $opt_f, $opt_a, $opt_m, $opt_d, $opt_u, $opt_w, $opt_W, $opt_k);

getopts('uhPpvcfkam:d:w:W');

$opt_h && usage();

die "Need at least one commit identifier!" unless @ARGV;

# Get git-config settings
my $repo = Git->repository();
$opt_w = $repo->config('cvsexportcommit.cvsdir') unless defined $opt_w;

if ($opt_w || $opt_W) {
	# Remember where GIT_DIR is before changing to CVS checkout
	unless ($ENV{GIT_DIR}) {
		# No GIT_DIR set. Figure it out for ourselves
		my $gd =`git-rev-parse --git-dir`;
		chomp($gd);
		$ENV{GIT_DIR} = $gd;
	}
	# Make sure GIT_DIR is absolute
	$ENV{GIT_DIR} = File::Spec->rel2abs($ENV{GIT_DIR});
}

if ($opt_w) {
	if (! -d $opt_w."/CVS" ) {
		die "$opt_w is not a CVS checkout";
	}
	chdir $opt_w or die "Cannot change to CVS checkout at $opt_w";
}
unless ($ENV{GIT_DIR} && -r $ENV{GIT_DIR}){
    die "GIT_DIR is not defined or is unreadable";
}


my @cvs;
if ($opt_d) {
	@cvs = ('cvs', '-d', $opt_d);
} else {
	@cvs = ('cvs');
}

# resolve target commit
my $commit;
$commit = pop @ARGV;
$commit = safe_pipe_capture('git-rev-parse', '--verify', "$commit^0");
chomp $commit;
if ($?) {
    die "The commit reference $commit did not resolve!";
}

# resolve what parent we want
my $parent;
if (@ARGV) {
    $parent = pop @ARGV;
    $parent =  safe_pipe_capture('git-rev-parse', '--verify', "$parent^0");
    chomp $parent;
    if ($?) {
	die "The parent reference did not resolve!";
    }
}

# find parents from the commit itself
my @commit  = safe_pipe_capture('git-cat-file', 'commit', $commit);
my @parents;
my $committer;
my $author;
my $stage = 'headers'; # headers, msg
my $title;
my $msg = '';

foreach my $line (@commit) {
    chomp $line;
    if ($stage eq 'headers' && $line eq '') {
	$stage = 'msg';
	next;
    }

    if ($stage eq 'headers') {
	if ($line =~ m/^parent (\w{40})$/) { # found a parent
	    push @parents, $1;
	} elsif ($line =~ m/^author (.+) \d+ [-+]\d+$/) {
	    $author = $1;
	} elsif ($line =~ m/^committer (.+) \d+ [-+]\d+$/) {
	    $committer = $1;
	}
    } else {
	$msg .= $line . "\n";
	unless ($title) {
	    $title = $line;
	}
    }
}

my $noparent = "0000000000000000000000000000000000000000";
if ($parent) {
    my $found;
    # double check that it's a valid parent
    foreach my $p (@parents) {
	if ($p eq $parent) {
	    $found = 1;
	    last;
	}; # found it
    }
    die "Did not find $parent in the parents for this commit!" if !$found and !$opt_P;
} else { # we don't have a parent from the cmdline...
    if (@parents == 1) { # it's safe to get it from the commit
	$parent = $parents[0];
    } elsif (@parents == 0) { # there is no parent
        $parent = $noparent;
    } else { # cannot choose automatically from multiple parents
        die "This commit has more than one parent -- please name the parent you want to use explicitly";
    }
}

my $go_back_to = 0;

if ($opt_W) {
    $opt_v && print "Resetting to $parent\n";
    $go_back_to = `git symbolic-ref HEAD 2> /dev/null ||
	git rev-parse HEAD` || die "Could not determine current branch";
    system("git checkout -q $parent^0") && die "Could not check out $parent^0";
}

$opt_v && print "Applying to CVS commit $commit from parent $parent\n";

# grab the commit message
open(MSG, ">.msg") or die "Cannot open .msg for writing";
if ($opt_m) {
    print MSG $opt_m;
}
print MSG $msg;
if ($opt_a) {
    print MSG "\n\nAuthor: $author\n";
    if ($author ne $committer) {
	print MSG "Committer: $committer\n";
    }
}
close MSG;

if ($parent eq $noparent) {
    `git-diff-tree --binary -p --root $commit >.cvsexportcommit.diff`;# || die "Cannot diff";
} else {
    `git-diff-tree --binary -p $parent $commit >.cvsexportcommit.diff`;# || die "Cannot diff";
}

## apply