2 # Example implementation for the Git filter protocol version 2
3 # See Documentation/gitattributes.txt, section "Filter Protocol"
5 # The script takes the list of supported protocol capabilities as
6 # arguments ("clean", "smudge", etc).
8 # This implementation supports special test cases:
9 # (1) If data with the pathname "clean-write-fail.r" is processed with
10 # a "clean" operation then the write operation will die.
11 # (2) If data with the pathname "smudge-write-fail.r" is processed with
12 # a "smudge" operation then the write operation will die.
13 # (3) If data with the pathname "error.r" is processed with any
14 # operation then the filter signals that it cannot or does not want
15 # to process the file.
16 # (4) If data with the pathname "abort.r" is processed with any
17 # operation then the filter signals that it cannot or does not want
18 # to process the file and any file after that is processed with the
26 my $MAX_PACKET_CONTENT_SIZE = 65516;
27 my @capabilities = @ARGV;
29 open my $debug, ">>", "rot13-filter.log" or die "cannot open log file: $!";
33 $str =~ y/A-Za-z/N-ZA-Mn-za-m/;
39 my $bytes_read = read STDIN, $buffer, 4;
40 if ( $bytes_read == 0 ) {
41 # EOF - Git stopped talking to us!
42 print $debug "STOP\n";
45 elsif ( $bytes_read != 4 ) {
46 die "invalid packet: '$buffer'";
48 my $pkt_size = hex($buffer);
49 if ( $pkt_size == 0 ) {
52 elsif ( $pkt_size > 4 ) {
53 my $content_size = $pkt_size - 4;
54 $bytes_read = read STDIN, $buffer, $content_size;
55 if ( $bytes_read != $content_size ) {
56 die "invalid packet ($content_size bytes expected; $bytes_read bytes read)";
58 return ( 0, $buffer );
61 die "invalid packet size: $pkt_size";
66 my ( $res, $buf ) = packet_bin_read();
67 unless ( $buf =~ s/\n$// ) {
68 die "A non-binary line MUST be terminated by an LF.";
70 return ( $res, $buf );
73 sub packet_bin_write {
75 print STDOUT sprintf( "%04x", length($buf) + 4 );
80 sub packet_txt_write {
81 packet_bin_write( $_[0] . "\n" );
85 print STDOUT sprintf( "%04x", 0 );
89 print $debug "START\n";
92 ( packet_txt_read() eq ( 0, "git-filter-client" ) ) || die "bad initialize";
93 ( packet_txt_read() eq ( 0, "version=2" ) ) || die "bad version";
94 ( packet_bin_read() eq ( 1, "" ) ) || die "bad version end";
96 packet_txt_write("git-filter-server");
97 packet_txt_write("version=2");
100 ( packet_txt_read() eq ( 0, "capability=clean" ) ) || die "bad capability";
101 ( packet_txt_read() eq ( 0, "capability=smudge" ) ) || die "bad capability";
102 ( packet_bin_read() eq ( 1, "" ) ) || die "bad capability end";
104 foreach (@capabilities) {
105 packet_txt_write( "capability=" . $_ );
108 print $debug "init handshake complete\n";
112 my ($command) = packet_txt_read() =~ /^command=([^=]+)$/;
113 print $debug "IN: $command";
116 my ($pathname) = packet_txt_read() =~ /^pathname=([^=]+)$/;
117 print $debug " $pathname";
129 ( $done, $buffer ) = packet_bin_read();
132 print $debug " " . length($input) . " [OK] -- ";
137 if ( $pathname eq "error.r" or $pathname eq "abort.r" ) {
140 elsif ( $command eq "clean" and grep( /^clean$/, @capabilities ) ) {
141 $output = rot13($input);
143 elsif ( $command eq "smudge" and grep( /^smudge$/, @capabilities ) ) {
144 $output = rot13($input);
147 die "bad command '$command'";
150 print $debug "OUT: " . length($output) . " ";
153 if ( $pathname eq "error.r" ) {
154 print $debug "[ERROR]\n";
156 packet_txt_write("status=error");
159 elsif ( $pathname eq "abort.r" ) {
160 print $debug "[ABORT]\n";
162 packet_txt_write("status=abort");
166 packet_txt_write("status=success");
169 if ( $pathname eq "${command}-write-fail.r" ) {
170 print $debug "[WRITE FAIL]\n";
172 die "${command} write error";
175 while ( length($output) > 0 ) {
176 my $packet = substr( $output, 0, $MAX_PACKET_CONTENT_SIZE );
177 packet_bin_write($packet);
178 # dots represent the number of packets
180 if ( length($output) > $MAX_PACKET_CONTENT_SIZE ) {
181 $output = substr( $output, $MAX_PACKET_CONTENT_SIZE );
188 print $debug " [OK]\n";