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
25 my $MAX_PACKET_CONTENT_SIZE = 65516;
26 my @capabilities = @ARGV;
28 open my $debug, ">>", "rot13-filter.log" or die "cannot open log file: $!";
32 $str =~ y/A-Za-z/N-ZA-Mn-za-m/;
38 my $bytes_read = read STDIN
, $buffer, 4;
39 if ( $bytes_read == 0 ) {
40 # EOF - Git stopped talking to us!
41 print $debug "STOP\n";
44 elsif ( $bytes_read != 4 ) {
45 die "invalid packet: '$buffer'";
47 my $pkt_size = hex($buffer);
48 if ( $pkt_size == 0 ) {
51 elsif ( $pkt_size > 4 ) {
52 my $content_size = $pkt_size - 4;
53 $bytes_read = read STDIN
, $buffer, $content_size;
54 if ( $bytes_read != $content_size ) {
55 die "invalid packet ($content_size bytes expected; $bytes_read bytes read)";
57 return ( 0, $buffer );
60 die "invalid packet size: $pkt_size";
65 my ( $res, $buf ) = packet_bin_read
();
66 unless ( $buf =~ s/\n$// ) {
67 die "A non-binary line MUST be terminated by an LF.";
69 return ( $res, $buf );
72 sub packet_bin_write
{
74 print STDOUT
sprintf( "%04x", length($buf) + 4 );
79 sub packet_txt_write
{
80 packet_bin_write
( $_[0] . "\n" );
84 print STDOUT
sprintf( "%04x", 0 );
88 print $debug "START\n";
91 ( packet_txt_read
() eq ( 0, "git-filter-client" ) ) || die "bad initialize";
92 ( packet_txt_read
() eq ( 0, "version=2" ) ) || die "bad version";
93 ( packet_bin_read
() eq ( 1, "" ) ) || die "bad version end";
95 packet_txt_write
("git-filter-server");
96 packet_txt_write
("version=2");
99 ( packet_txt_read
() eq ( 0, "capability=clean" ) ) || die "bad capability";
100 ( packet_txt_read
() eq ( 0, "capability=smudge" ) ) || die "bad capability";
101 ( packet_bin_read
() eq ( 1, "" ) ) || die "bad capability end";
103 foreach (@capabilities) {
104 packet_txt_write
( "capability=" . $_ );
107 print $debug "init handshake complete\n";
111 my ($command) = packet_txt_read
() =~ /^command=([^=]+)$/;
112 print $debug "IN: $command";
115 my ($pathname) = packet_txt_read
() =~ /^pathname=([^=]+)$/;
116 print $debug " $pathname";
128 ( $done, $buffer ) = packet_bin_read
();
131 print $debug " " . length($input) . " [OK] -- ";
136 if ( $pathname eq "error.r" or $pathname eq "abort.r" ) {
139 elsif ( $command eq "clean" and grep( /^clean$/, @capabilities ) ) {
140 $output = rot13
($input);
142 elsif ( $command eq "smudge" and grep( /^smudge$/, @capabilities ) ) {
143 $output = rot13
($input);
146 die "bad command '$command'";
149 print $debug "OUT: " . length($output) . " ";
152 if ( $pathname eq "error.r" ) {
153 print $debug "[ERROR]\n";
155 packet_txt_write
("status=error");
158 elsif ( $pathname eq "abort.r" ) {
159 print $debug "[ABORT]\n";
161 packet_txt_write
("status=abort");
165 packet_txt_write
("status=success");
168 if ( $pathname eq "${command}-write-fail.r" ) {
169 print $debug "[WRITE FAIL]\n";
171 die "${command} write error";
174 while ( length($output) > 0 ) {
175 my $packet = substr( $output, 0, $MAX_PACKET_CONTENT_SIZE );
176 packet_bin_write
($packet);
177 # dots represent the number of packets
179 if ( length($output) > $MAX_PACKET_CONTENT_SIZE ) {
180 $output = substr( $output, $MAX_PACKET_CONTENT_SIZE );
187 print $debug " [OK]\n";