diff options
Diffstat (limited to 'perl/Git/Packet.pm')
| -rw-r--r-- | perl/Git/Packet.pm | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/perl/Git/Packet.pm b/perl/Git/Packet.pm new file mode 100644 index 0000000..b75738b --- /dev/null +++ b/perl/Git/Packet.pm @@ -0,0 +1,173 @@ +package Git::Packet; +use 5.008; +use strict; +use warnings; +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; |