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-rw-r--r--perl/Git/Packet.pm173
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..d144f51
--- /dev/null
+++ b/perl/Git/Packet.pm
@@ -0,0 +1,173 @@
+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;