1#!/usr/local/bin/perl 2# 3# Example implementation for the Git filter protocol version 2 4# See Documentation/gitattributes.txt, section "Filter Protocol" 5# 6# Please note, this pass-thru filter is a minimal skeleton. No proper 7# error handling was implemented. 8# 9 10use strict; 11use warnings; 12 13my $MAX_PACKET_CONTENT_SIZE = 65516; 14 15sub packet_bin_read { 16 my $buffer; 17 my $bytes_read = read STDIN, $buffer, 4; 18 if ( $bytes_read == 0 ) { 19 20 # EOF - Git stopped talking to us! 21 exit(); 22 } 23 elsif ( $bytes_read != 4 ) { 24 die "invalid packet: '$buffer'"; 25 } 26 my $pkt_size = hex($buffer); 27 if ( $pkt_size == 0 ) { 28 return ( 1, "" ); 29 } 30 elsif ( $pkt_size > 4 ) { 31 my $content_size = $pkt_size - 4; 32 $bytes_read = read STDIN, $buffer, $content_size; 33 if ( $bytes_read != $content_size ) { 34 die "invalid packet ($content_size bytes expected; $bytes_read bytes read)"; 35 } 36 return ( 0, $buffer ); 37 } 38 else { 39 die "invalid packet size: $pkt_size"; 40 } 41} 42 43sub packet_txt_read { 44 my ( $res, $buf ) = packet_bin_read(); 45 unless ( $buf =~ s/\n$// ) { 46 die "A non-binary line MUST be terminated by an LF."; 47 } 48 return ( $res, $buf ); 49} 50 51sub packet_bin_write { 52 my $buf = shift; 53 print STDOUT sprintf( "%04x", length($buf) + 4 ); 54 print STDOUT $buf; 55 STDOUT->flush(); 56} 57 58sub packet_txt_write { 59 packet_bin_write( $_[0] . "\n" ); 60} 61 62sub packet_flush { 63 print STDOUT sprintf( "%04x", 0 ); 64 STDOUT->flush(); 65} 66 67( packet_txt_read() eq ( 0, "git-filter-client" ) ) || die "bad initialize"; 68( packet_txt_read() eq ( 0, "version=2" ) ) || die "bad version"; 69( packet_bin_read() eq ( 1, "" ) ) || die "bad version end"; 70 71packet_txt_write("git-filter-server"); 72packet_txt_write("version=2"); 73packet_flush(); 74 75( packet_txt_read() eq ( 0, "capability=clean" ) ) || die "bad capability"; 76( packet_txt_read() eq ( 0, "capability=smudge" ) ) || die "bad capability"; 77( packet_bin_read() eq ( 1, "" ) ) || die "bad capability end"; 78 79packet_txt_write("capability=clean"); 80packet_txt_write("capability=smudge"); 81packet_flush(); 82 83while (1) { 84 my ($command) = packet_txt_read() =~ /^command=(.+)$/; 85 my ($pathname) = packet_txt_read() =~ /^pathname=(.+)$/; 86 87 if ( $pathname eq "" ) { 88 die "bad pathname '$pathname'"; 89 } 90 91 packet_bin_read(); 92 93 my $input = ""; 94 { 95 binmode(STDIN); 96 my $buffer; 97 my $done = 0; 98 while ( !$done ) { 99 ( $done, $buffer ) = packet_bin_read(); 100 $input .= $buffer; 101 } 102 } 103 104 my $output; 105 if ( $command eq "clean" ) { 106 ### Perform clean here ### 107 $output = $input; 108 } 109 elsif ( $command eq "smudge" ) { 110 ### Perform smudge here ### 111 $output = $input; 112 } 113 else { 114 die "bad command '$command'"; 115 } 116 117 packet_txt_write("status=success"); 118 packet_flush(); 119 while ( length($output) > 0 ) { 120 my $packet = substr( $output, 0, $MAX_PACKET_CONTENT_SIZE ); 121 packet_bin_write($packet); 122 if ( length($output) > $MAX_PACKET_CONTENT_SIZE ) { 123 $output = substr( $output, $MAX_PACKET_CONTENT_SIZE ); 124 } 125 else { 126 $output = ""; 127 } 128 } 129 packet_flush(); # flush content! 130 packet_flush(); # empty list, keep "status=success" unchanged! 131 132} 133