package Git::Packet;
use 5.008;
use strict;
use warnings $ENV{GIT_PERL_FATAL_WARNINGS} ? qw(FATAL all) : ();
BEGIN {
require Exporter;
if ($] < 5.008003) {
*import = \&Exporter::import;
} else {
# Exporter 5.57 which supports this invocation was
# released with perl 5.8.3
Exporter->import('import');
}
}
our @EXPORT = qw(
packet_compare_lists
packet_bin_read
packet_txt_read
packet_key_val_read
packet_bin_write
packet_txt_write
packet_flush
packet_initialize
packet_read_capabilities
packet_read_and_check_capabilities
packet_check_and_write_capabilities
);
our @EXPORT_OK = @EXPORT;
sub packet_compare_lists {
my ($expect, @result) = @_;
my $ix;
if (scalar @$expect != scalar @result) {
return undef;
}
for ($ix = 0; $ix < $#result; $ix++) {
if ($expect->[$ix] ne $result[$ix]) {
return undef;
}
}
return 1;
}
sub packet_bin_read {
my $buffer;
my $bytes_read = read STDIN, $buffer, 4;
if ( $bytes_read == 0 ) {
# EOF - Git stopped talking to us!
return ( -1, "" );
} elsif ( $bytes_read != 4 ) {
die "invalid packet: '$buffer'";
}
my $pkt_size = hex($buffer);
if ( $pkt_size == 0 ) {
return ( 1, "" );
} elsif ( $pkt_size > 4 ) {
my $content_size = $pkt_size - 4;
$bytes_read = read STDIN, $buffer, $content_size;
if ( $bytes_read != $content_size ) {
die "invalid packet ($content_size bytes expected; $bytes_read bytes read)";
}
return ( 0, $buffer );
} else {
die "invalid packet size: $pkt_size";
}
}
sub remove_final_lf_or_die {
my $buf = shift;
if ( $buf =~ s/\n$// ) {
return $buf;
}
die "A non-binary line MUST be terminated by an LF.\n"
. "Received: '$buf'";
}
sub packet_txt_read {
my ( $res, $buf ) = packet_bin_read();
if ( $res != -1 and $buf ne '' ) {
$buf = remove_final_lf_or_die($buf);
}
return ( $res, $buf );
}
# Read a text packet, expecting that it is in the form "key=value" for
# the given $key. An EOF does not trigger any error and is reported
# back to the caller (like packet_txt_read() does). Die if the "key"
# part of "key=value" does not match the given $key, or the value part
# is empty.
sub packet_key_val_read {
my ( $key ) = @_;
my ( $res, $buf ) = packet_txt_read();
if ( $res == -1 or ( $buf =~ s/^$key=// and $buf ne '' ) ) {
return ( $res, $buf );
}
die "bad $key: '$buf'";
}
sub packet_bin_write {
my $buf = shift;
print STDOUT sprintf( "%04x", length($buf) + 4 );
print STDOUT $buf;
STDOUT->flush();
}
sub packet_txt_write {
packet_bin_write( $_[0] . "\n" );
}
sub packet_flush {
print STDOUT sprintf( "%04x", 0 );
STDOUT->flush();
}
sub packet_initialize {
my ($name, $version) = @_;
packet_compare_lists([0, $name . "-client"], packet_txt_read()) ||
die "bad initialize";
packet_compare_lists([0, "version=" . $version], packet_txt_read()) ||
die "bad version";
packet_compare_lists([1, ""], packet_bin_read()) ||
die "bad version end";
packet_txt_write( $name . "-server" );
packet_txt_write( "version=" . $version );
packet_flush();
}
sub packet_read_capabilities {
my @cap;
while (1) {
my ( $res, $buf ) = packet_bin_read();
if ( $res == -1 ) {
die "unexpected EOF when reading capabilities";
}
return ( $res, @cap ) if ( $res != 0 );
$buf = remove_final_lf_or_die($buf);
unless ( $buf =~ s/capability=// ) {
die "bad capability buf: '$buf'";
}
push @cap, $buf;
}
}
# Read remote capabilities and check them against capabilities we require
sub packet_read_and_check_capabilities {
my @required_caps = @_;
my ($res, @remote_caps) = packet_read_capabilities();
my %remote_caps = map { $_ => 1 } @remote_caps;
foreach (@required_caps) {
unless (exists($remote_caps{$_})) {
die "required '$_' capability not available from remote" ;
}
}
return %remote_caps;
}
# Check our capabilities we want to advertise against the remote ones
# and then advertise our capabilities
sub packet_check_and_write_capabilities {
my ($remote_caps, @our_caps) = @_;
foreach (@our_caps) {
unless (exists($remote_caps->{$_})) {
die "our capability '$_' is not available from remote"
}
packet_txt_write( "capability=" . $_ );
}
packet_flush();
}
1;
Mini Shell