1 package Git::PurePerl::Pack;
3 use MooseX::StrictConstructor;
4 use MooseX::Types::Path::Class;
5 use Compress::Raw::Zlib;
7 use namespace::autoclean;
10 ( is => 'ro', isa => 'Path::Class::File', required => 1, coerce => 1 );
11 has 'fh' => ( is => 'rw', isa => 'IO::File', required => 0 );
13 my @TYPES = ( 'none', 'commit', 'tree', 'blob', 'tag', '', 'ofs_delta',
20 my $OBJ_OFS_DELTA = 6;
21 my $OBJ_REF_DELTA = 7;
27 my $fh = IO::File->new( $self->filename ) || confess($!);
33 my ( $self, $want_sha1 ) = @_;
34 return Data::Stream::Bulk::Array->new(
35 array => [ $self->index->all_sha1s ] );
39 my ( $self, $offset ) = @_;
40 my $obj_offset = $offset;
43 $fh->seek( $offset, 0 ) || die "Error seeking in pack: $!";
44 $fh->read( my $c, 1 ) || die "Error reading from pack: $!";
45 $c = unpack( 'C', $c ) || die $!;
47 my $size = ( $c & 0xf );
48 my $type_number = ( $c >> 4 ) & 7;
49 my $type = $TYPES[$type_number] || confess "invalid type $type_number";
54 while ( ( $c & 0x80 ) != 0 ) {
55 $fh->read( $c, 1 ) || die $!;
56 $c = unpack( 'C', $c ) || die $!;
57 $size |= ( ( $c & 0x7f ) << $shift );
62 if ( $type eq 'ofs_delta' || $type eq 'ref_delta' ) {
63 ( $type, $size, my $content )
64 = $self->unpack_deltified( $type, $offset, $obj_offset, $size );
65 return ( $type, $size, $content );
67 } elsif ( $type eq 'commit'
72 my $content = $self->read_compressed( $offset, $size );
73 return ( $type, $size, $content );
75 confess "invalid type $type";
80 my ( $self, $offset, $size ) = @_;
83 $fh->seek( $offset, 0 ) || die $!;
84 my ( $deflate, $status ) = Compress::Raw::Zlib::Inflate->new(
90 while ( length($out) < $size ) {
91 $fh->read( my $block, 4096 ) || die $!;
92 my $status = $deflate->inflate( $block, $out );
94 confess length($out)." is not $size" unless length($out) == $size;
96 $fh->seek( $offset + $deflate->total_in, 0 ) || die $!;
100 sub unpack_deltified {
101 my ( $self, $type, $offset, $obj_offset, $size ) = @_;
106 $fh->seek( $offset, 0 ) || die $!;
107 $fh->read( my $data, $SHA1Size ) || die $!;
108 my $sha1 = unpack( 'H*', $data );
110 if ( $type eq 'ofs_delta' ) {
112 my $c = unpack( 'C', substr( $data, $i, 1 ) );
113 my $base_offset = $c & 0x7f;
115 while ( ( $c & 0x80 ) != 0 ) {
116 $c = unpack( 'C', substr( $data, ++$i, 1 ) );
119 $base_offset |= $c & 0x7f;
121 $base_offset = $obj_offset - $base_offset;
124 ( $type, undef, $base ) = $self->unpack_object($base_offset);
126 ( $type, undef, $base ) = $self->get_object($sha1);
127 $offset += $SHA1Size;
131 my $delta = $self->read_compressed( $offset, $size );
132 my $new = $self->patch_delta( $base, $delta );
134 return ( $type, length($new), $new );
138 my ( $self, $base, $delta ) = @_;
140 my ( $src_size, $pos ) = $self->patch_delta_header_size( $delta, 0 );
141 if ( $src_size != length($base) ) {
142 confess "invalid delta data";
145 ( my $dest_size, $pos ) = $self->patch_delta_header_size( $delta, $pos );
148 while ( $pos < length($delta) ) {
149 my $c = substr( $delta, $pos, 1 );
150 $c = unpack( 'C', $c );
152 if ( ( $c & 0x80 ) != 0 ) {
156 $cp_off = unpack( 'C', substr( $delta, $pos++, 1 ) )
157 if ( $c & 0x01 ) != 0;
158 $cp_off |= unpack( 'C', substr( $delta, $pos++, 1 ) ) << 8
159 if ( $c & 0x02 ) != 0;
160 $cp_off |= unpack( 'C', substr( $delta, $pos++, 1 ) ) << 16
161 if ( $c & 0x04 ) != 0;
162 $cp_off |= unpack( 'C', substr( $delta, $pos++, 1 ) ) << 24
163 if ( $c & 0x08 ) != 0;
164 $cp_size = unpack( 'C', substr( $delta, $pos++, 1 ) )
165 if ( $c & 0x10 ) != 0;
166 $cp_size |= unpack( 'C', substr( $delta, $pos++, 1 ) ) << 8
167 if ( $c & 0x20 ) != 0;
168 $cp_size |= unpack( 'C', substr( $delta, $pos++, 1 ) ) << 16
169 if ( $c & 0x40 ) != 0;
170 $cp_size = 0x10000 if $cp_size == 0;
172 $dest .= substr( $base, $cp_off, $cp_size );
173 } elsif ( $c != 0 ) {
174 $dest .= substr( $delta, $pos, $c );
177 confess 'invalid delta data';
181 if ( length($dest) != $dest_size ) {
182 confess 'invalid delta data';
187 sub patch_delta_header_size {
188 my ( $self, $delta, $pos ) = @_;
194 my $c = substr( $delta, $pos, 1 );
195 unless ( defined $c ) {
196 confess 'invalid delta header';
198 $c = unpack( 'C', $c );
201 $size |= ( $c & 0x7f ) << $shift;
203 last if ( $c & 0x80 ) == 0;
205 return ( $size, $pos );
208 __PACKAGE__->meta->make_immutable;