1 package DBM::Deep::Engine3;
7 our $VERSION = q(0.99_03);
12 # * Every method in here assumes that the storage has been appropriately
13 # safeguarded. This can be anything from flock() to some sort of manual
14 # mutex. But, it's the caller's responsability to make sure that this has
17 # Setup file and tag signatures. These should never change.
18 sub SIG_FILE () { 'DPDB' }
19 sub SIG_HEADER () { 'h' }
20 sub SIG_INTERNAL () { 'i' }
21 sub SIG_HASH () { 'H' }
22 sub SIG_ARRAY () { 'A' }
23 sub SIG_NULL () { 'N' }
24 sub SIG_DATA () { 'D' }
25 sub SIG_INDEX () { 'I' }
26 sub SIG_BLIST () { 'B' }
27 sub SIG_FREE () { 'F' }
28 sub SIG_KEYS () { 'K' }
31 ################################################################################
33 # Please refer to the pack() documentation for further information
35 1 => 'C', # Unsigned char value
36 2 => 'n', # Unsigned short in "network" (big-endian) order
37 4 => 'N', # Unsigned long in "network" (big-endian) order
38 8 => 'Q', # Usigned quad (no order specified, presumably machine-dependent)
49 hash_size => 16, # In bytes
51 num_txns => 16, # HEAD plus 15 running txns
52 trans_id => 0, # Default to the HEAD
57 if ( defined $args->{pack_size} ) {
58 if ( lc $args->{pack_size} eq 'small' ) {
59 $args->{byte_size} = 2;
61 elsif ( lc $args->{pack_size} eq 'medium' ) {
62 $args->{byte_size} = 4;
64 elsif ( lc $args->{pack_size} eq 'large' ) {
65 $args->{byte_size} = 8;
68 die "Unknown pack_size value: '$args->{pack_size}'\n";
72 # Grab the parameters we want to use
73 foreach my $param ( keys %$self ) {
74 next unless exists $args->{$param};
75 $self->{$param} = $args->{$param};
78 $self->{byte_pack} = $StP{ $self->byte_size };
81 # Number of buckets per blist before another level of indexing is
82 # done. Increase this value for slightly greater speed, but larger database
83 # files. DO NOT decrease this value below 16, due to risk of recursive
86 if ( $self->{max_buckets} < 16 ) {
87 warn "Floor of max_buckets is 16. Setting it to 16 from '$self->{max_buckets}'\n";
88 $self->{max_buckets} = 16;
91 if ( !$self->{digest} ) {
93 $self->{digest} = \&Digest::MD5::md5;
99 ################################################################################
103 my ($obj, $key) = @_;
105 # This will be a Reference sector
106 my $sector = $self->_load_sector( $obj->_base_offset )
107 or die "How did read_value fail (no sector for '$obj')?!\n";
109 my $key_md5 = $self->_apply_digest( $key );
111 my $value_sector = $sector->get_data_for({
116 unless ( $value_sector ) {
117 $value_sector = DBM::Deep::Engine::Sector::Null->new({
122 $sector->write_data({
125 value => $value_sector,
129 return $value_sector->data;
136 # This will be a Reference sector
137 my $sector = $self->_load_sector( $obj->_base_offset )
138 or die "How did read_value fail (no sector for '$obj')?!\n";
140 return $sector->get_classname;
145 my ($obj, $key) = @_;
147 # This will be a Reference sector
148 my $sector = $self->_load_sector( $obj->_base_offset )
149 or die "How did key_exists fail (no sector for '$obj')?!\n";
151 my $data = $sector->get_data_for({
152 key_md5 => $self->_apply_digest( $key ),
156 # exists() returns 1 or '' for true/false.
157 return $data ? 1 : '';
162 my ($obj, $key) = @_;
164 my $sector = $self->_load_sector( $obj->_base_offset )
165 or die "How did delete_key fail (no sector for '$obj')?!\n";
167 return $sector->delete_key({
168 key_md5 => $self->_apply_digest( $key ),
172 my $key_md5 = $self->_apply_digest( $key );
174 # XXX What should happen if this fails?
175 my $blist = $sector->get_bucket_list({
177 }) or die "How did delete_key fail (no blist)?!\n";
179 return $blist->delete_md5( $key_md5 );
184 my ($obj, $key, $value) = @_;
186 my $r = Scalar::Util::reftype( $value ) || '';
189 last if $r eq 'HASH';
190 last if $r eq 'ARRAY';
192 DBM::Deep->_throw_error(
193 "Storage of references of type '$r' is not supported."
198 if ( !defined $value ) {
199 $class = 'DBM::Deep::Engine::Sector::Null';
201 elsif ( $r eq 'ARRAY' || $r eq 'HASH' ) {
202 if ( $r eq 'ARRAY' && tied(@$value) ) {
203 DBM::Deep->_throw_error( "Cannot store something that is tied." );
205 if ( $r eq 'HASH' && tied(%$value) ) {
206 DBM::Deep->_throw_error( "Cannot store something that is tied." );
208 $class = 'DBM::Deep::Engine::Sector::Reference';
209 $type = substr( $r, 0, 1 );
212 $class = 'DBM::Deep::Engine::Sector::Scalar';
215 # This will be a Reference sector
216 my $sector = $self->_load_sector( $obj->_base_offset )
217 or die "How did write_value fail (no sector for '$obj')?!\n";
219 # Create this after loading the reference sector in case something bad happens.
220 # This way, we won't allocate value sector(s) needlessly.
221 my $value_sector = $class->new({
227 $sector->write_data({
229 key_md5 => $self->_apply_digest( $key ),
230 value => $value_sector,
233 # This code is to make sure we write all the values in the $value to the disk
234 # and to make sure all changes to $value after the assignment are reflected
235 # on disk. This may be counter-intuitive at first, but it is correct dwimmery.
236 # NOTE - simply tying $value won't perform a STORE on each value. Hence, the
237 # copy to a temp value.
238 if ( $r eq 'ARRAY' ) {
240 tie @$value, 'DBM::Deep', {
241 base_offset => $value_sector->offset,
242 storage => $self->storage,
246 bless $value, 'DBM::Deep::Array' unless Scalar::Util::blessed( $value );
248 elsif ( $r eq 'HASH' ) {
250 tie %$value, 'DBM::Deep', {
251 base_offset => $value_sector->offset,
252 storage => $self->storage,
257 bless $value, 'DBM::Deep::Hash' unless Scalar::Util::blessed( $value );
265 my ($obj, $prev_key) = @_;
267 # XXX Need to add logic about resetting the iterator if any key in the reference has changed
268 unless ( $prev_key ) {
269 $obj->{iterator} = DBM::Deep::Engine::Iterator->new({
270 base_offset => $obj->_base_offset,
275 return $obj->{iterator}->get_next_key;
278 ################################################################################
284 # We're opening the file.
285 unless ( $obj->_base_offset ) {
286 my $bytes_read = $self->_read_file_header;
288 # Creating a new file
289 unless ( $bytes_read ) {
290 $self->_write_file_header;
292 # 1) Create Array/Hash entry
293 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
297 $obj->{base_offset} = $initial_reference->offset;
299 $self->storage->flush;
301 # Reading from an existing file
303 $obj->{base_offset} = $bytes_read;
304 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
306 offset => $obj->_base_offset,
308 unless ( $initial_reference ) {
309 DBM::Deep->_throw_error("Corrupted file, no master index record");
312 unless ($obj->_type eq $initial_reference->type) {
313 DBM::Deep->_throw_error("File type mismatch");
325 if ( $self->trans_id ) {
326 DBM::Deep->throw_error( "Cannot begin_work within a transaction" );
329 my @slots = $self->read_transaction_slots;
330 for my $i ( 1 .. @slots ) {
333 $self->set_trans_id( $i );
336 $self->write_transaction_slots( @slots );
338 if ( !$self->trans_id ) {
339 DBM::Deep->throw_error( "Cannot begin_work - no available transactions" );
349 if ( !$self->trans_id ) {
350 DBM::Deep->throw_error( "Cannot rollback without a transaction" );
358 if ( !$self->trans_id ) {
359 DBM::Deep->throw_error( "Cannot commit without a transaction" );
363 sub read_transaction_slots {
365 return split '', unpack( "b32", $self->storage->read_at( $self->trans_loc, 4 ) );
368 sub write_transaction_slots {
370 $self->storage->print_at( $self->trans_loc,
371 pack( "b32", join('', @_) ),
375 ################################################################################
378 my $header_fixed = length( SIG_FILE ) + 1 + 4 + 4;
380 sub _write_file_header {
383 my $header_var = 1 + 1 + 4 + 2 * $self->byte_size;
385 my $loc = $self->storage->request_space( $header_fixed + $header_var );
387 $self->storage->print_at( $loc,
390 pack('N', 1), # header version - at this point, we're at 9 bytes
391 pack('N', $header_var), # header size
392 # --- Above is $header_fixed. Below is $header_var
393 pack('C', $self->byte_size),
394 pack('C', $self->max_buckets),
395 pack('N', 0 ), # Running transactions
396 pack($StP{$self->byte_size}, 0), # Start of free chain (blist size)
397 pack($StP{$self->byte_size}, 0), # Start of free chain (data size)
400 $self->set_trans_loc( $header_fixed + 2 );
401 $self->set_chains_loc( $header_fixed + 6 );
406 sub _read_file_header {
409 my $buffer = $self->storage->read_at( 0, $header_fixed );
410 return unless length($buffer);
412 my ($file_signature, $sig_header, $header_version, $size) = unpack(
416 unless ( $file_signature eq SIG_FILE ) {
417 $self->storage->close;
418 DBM::Deep->_throw_error( "Signature not found -- file is not a Deep DB" );
421 unless ( $sig_header eq SIG_HEADER ) {
422 $self->storage->close;
423 DBM::Deep->_throw_error( "Old file version found." );
426 my $buffer2 = $self->storage->read_at( undef, $size );
427 my @values = unpack( 'C C', $buffer2 );
429 $self->set_trans_loc( $header_fixed + 2 );
430 $self->set_chains_loc( $header_fixed + 6 );
432 if ( @values < 2 || grep { !defined } @values ) {
433 $self->storage->close;
434 DBM::Deep->_throw_error("Corrupted file - bad header");
437 #XXX Add warnings if values weren't set right
438 @{$self}{qw(byte_size max_buckets)} = @values;
440 my $header_var = 1 + 1 + 4 + 2 * $self->byte_size;
441 unless ( $size eq $header_var ) {
442 $self->storage->close;
443 DBM::Deep->_throw_error( "Unexpected size found ($size <-> $header_var)." );
446 return length($buffer) + length($buffer2);
454 my $type = $self->storage->read_at( $offset, 1 );
455 return if $type eq chr(0);
457 if ( $type eq $self->SIG_ARRAY || $type eq $self->SIG_HASH ) {
458 return DBM::Deep::Engine::Sector::Reference->new({
464 # XXX Don't we need key_md5 here?
465 elsif ( $type eq $self->SIG_BLIST ) {
466 return DBM::Deep::Engine::Sector::BucketList->new({
472 elsif ( $type eq $self->SIG_NULL ) {
473 return DBM::Deep::Engine::Sector::Null->new({
479 elsif ( $type eq $self->SIG_DATA ) {
480 return DBM::Deep::Engine::Sector::Scalar->new({
486 # This was deleted from under us, so just return and let the caller figure it out.
487 elsif ( $type eq $self->SIG_FREE ) {
491 die "'$offset': Don't know what to do with type '$type'\n";
496 return $self->{digest}->(@_);
499 sub _add_free_sector {
501 my ($offset, $size) = @_;
505 if ( $size == 256 ) {
506 $chains_offset = $self->byte_size;
513 my $old_head = $self->storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
515 $self->storage->print_at( $self->chains_loc + $chains_offset,
516 pack( $StP{$self->byte_size}, $offset ),
519 # Record the old head in the new sector after the signature
520 $self->storage->print_at( $offset + 1, $old_head );
523 sub _request_sector {
529 if ( $size == 256 ) {
530 $chains_offset = $self->byte_size;
537 my $old_head = $self->storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
538 my $loc = unpack( $StP{$self->byte_size}, $old_head );
540 # We don't have any free sectors of the right size, so allocate a new one.
542 return $self->storage->request_space( $size );
545 my $new_head = $self->storage->read_at( $loc + 1, $self->byte_size );
546 $self->storage->print_at( $self->chains_loc + $chains_offset, $new_head );
551 ################################################################################
553 sub storage { $_[0]{storage} }
554 sub byte_size { $_[0]{byte_size} }
555 sub hash_size { $_[0]{hash_size} }
556 sub num_txns { $_[0]{num_txns} }
557 sub max_buckets { $_[0]{max_buckets} }
558 sub blank_md5 { chr(0) x $_[0]->hash_size }
560 sub trans_id { $_[0]{trans_id} }
561 sub set_trans_id { $_[0]{trans_id} = $_[1] }
563 sub trans_loc { $_[0]{trans_loc} }
564 sub set_trans_loc { $_[0]{trans_loc} = $_[1] }
566 sub chains_loc { $_[0]{chains_loc} }
567 sub set_chains_loc { $_[0]{chains_loc} = $_[1] }
569 ################################################################################
571 package DBM::Deep::Engine::Iterator;
579 engine => $args->{engine},
580 base_offset => $args->{base_offset},
583 Scalar::Util::weaken( $self->{engine} );
590 $self->{breadcrumbs} = [];
596 my $crumbs = $self->{breadcrumbs};
598 unless ( @$crumbs ) {
599 # This will be a Reference sector
600 my $sector = $self->{engine}->_load_sector( $self->{base_offset} )
601 # or die "Iterator: How did this fail (no ref sector for '$self->{base_offset}')?!\n";
602 # If no sector is found, thist must have been deleted from under us.
604 push @$crumbs, [ $sector->get_blist_loc, 0 ];
609 my ($offset, $idx) = @{ $crumbs->[-1] };
615 if ( $idx >= $self->{engine}->max_buckets ) {
620 my $sector = $self->{engine}->_load_sector( $offset )
621 or die "Iterator: How did this fail (no blist sector for '$offset')?!\n";
623 #XXX Think this through!
624 my $loc = $sector->get_data_location_for({
632 my $key_sector = $sector->get_key_for( $idx );
633 unless ( $key_sector ) {
639 $key = $key_sector->data;
646 package DBM::Deep::Engine::Sector;
649 my $self = bless $_[1], $_[0];
650 Scalar::Util::weaken( $self->{engine} );
655 sub clone { die "Must be implemented in the child class" }
657 sub engine { $_[0]{engine} }
658 sub offset { $_[0]{offset} }
659 sub type { $_[0]{type} }
664 $self->engine->storage->print_at( $self->offset,
665 $self->engine->SIG_FREE,
666 chr(0) x ($self->size - 1),
669 $self->engine->_add_free_sector(
670 $self->offset, $self->size,
676 package DBM::Deep::Engine::Sector::Data;
678 our @ISA = qw( DBM::Deep::Engine::Sector );
681 sub size { return 256 }
685 return ref($self)->new({
686 engine => $self->engine,
692 package DBM::Deep::Engine::Sector::Scalar;
694 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
699 my $chain_loc = $self->chain_loc;
701 $self->SUPER::free();
704 $self->engine->_load_sector( $chain_loc )->free;
710 sub type { $_[0]{engine}->SIG_DATA }
714 my $engine = $self->engine;
716 unless ( $self->offset ) {
717 my $data_section = $self->size - 3 - 1 * $engine->byte_size;
719 $self->{offset} = $engine->_request_sector( $self->size );
721 my $data = delete $self->{data};
722 my $dlen = length $data;
724 my $curr_offset = $self->offset;
725 while ( $continue ) {
729 my ($leftover, $this_len, $chunk);
730 if ( $dlen > $data_section ) {
732 $this_len = $data_section;
733 $chunk = substr( $data, 0, $this_len );
735 $dlen -= $data_section;
736 $next_offset = $engine->_request_sector( $self->size );
737 $data = substr( $data, $this_len );
740 $leftover = $data_section - $dlen;
747 $engine->storage->print_at( $curr_offset,
748 $self->type, # Sector type
749 pack( $StP{1}, 0 ), # Recycled counter
750 pack( $StP{$engine->byte_size}, $next_offset ), # Chain loc
751 pack( $StP{1}, $this_len ), # Data length
752 $chunk, # Data to be stored in this sector
753 chr(0) x $leftover, # Zero-fill the rest
756 $curr_offset = $next_offset;
766 my $buffer = $self->engine->storage->read_at(
767 $self->offset + 2 + $self->engine->byte_size, 1
770 return unpack( $StP{1}, $buffer );
775 my $chain_loc = $self->engine->storage->read_at(
776 $self->offset + 2, $self->engine->byte_size,
778 return unpack( $StP{$self->engine->byte_size}, $chain_loc );
786 my $chain_loc = $self->chain_loc;
788 $data .= $self->engine->storage->read_at(
789 $self->offset + 2 + $self->engine->byte_size + 1, $self->data_length,
792 last unless $chain_loc;
794 $self = $self->engine->_load_sector( $chain_loc );
800 package DBM::Deep::Engine::Sector::Null;
802 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
804 sub type { $_[0]{engine}->SIG_NULL }
805 sub data_length { 0 }
811 my $engine = $self->engine;
813 unless ( $self->offset ) {
814 my $leftover = $self->size - 3 - 1 * $engine->byte_size;
816 $self->{offset} = $engine->_request_sector( $self->size );
817 $engine->storage->print_at( $self->offset,
818 $self->type, # Sector type
819 pack( $StP{1}, 0 ), # Recycled counter
820 pack( $StP{$engine->byte_size}, 0 ), # Chain loc
821 pack( $StP{1}, $self->data_length ), # Data length
822 chr(0) x $leftover, # Zero-fill the rest
829 package DBM::Deep::Engine::Sector::Reference;
831 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
836 my $engine = $self->engine;
838 unless ( $self->offset ) {
839 my $classname = Scalar::Util::blessed( delete $self->{data} );
840 my $leftover = $self->size - 4 - 2 * $engine->byte_size;
842 my $class_offset = 0;
843 if ( defined $classname ) {
844 my $class_sector = DBM::Deep::Engine::Sector::Scalar->new({
845 engine => $self->engine,
848 $class_offset = $class_sector->offset;
851 $self->{offset} = $engine->_request_sector( $self->size );
852 $engine->storage->print_at( $self->offset,
853 $self->type, # Sector type
854 pack( $StP{1}, 0 ), # Recycled counter
855 pack( $StP{$engine->byte_size}, 0 ), # Index/BList loc
856 pack( $StP{$engine->byte_size}, $class_offset ), # Classname loc
857 chr(0) x $leftover, # Zero-fill the rest
863 $self->{type} = $engine->storage->read_at( $self->offset, 1 );
872 # Assume that the head is not allowed unless otherwise specified.
873 $args->{allow_head} = 0 unless exists $args->{allow_head};
875 # Assume we don't create a new blist location unless otherwise specified.
876 $args->{create} = 0 unless exists $args->{create};
878 my $blist = $self->get_bucket_list({
879 key_md5 => $args->{key_md5},
880 create => $args->{create},
882 return unless $blist && $blist->{found};
884 # At this point, $blist knows where the md5 is. What it -doesn't- know yet
885 # is whether or not this transaction has this key. That's part of the next
887 my $location = $blist->get_data_location_for({
888 allow_head => $args->{allow_head},
891 return $self->engine->_load_sector( $location );
898 my $blist = $self->get_bucket_list({
899 key_md5 => $args->{key_md5},
901 }) or die "How did write_value fail (no blist)?!\n";
903 # Handle any transactional bookkeeping.
904 if ( $self->engine->trans_id ) {
905 if ( ! $blist->{found} ) {
906 $blist->mark_deleted({
912 my @transactions = $self->engine->read_transaction_slots;
913 my @trans_ids = grep { $transactions[$_] } 0 .. $#transactions;
914 if ( $blist->{found} ) {
916 my $old_value = $blist->get_data_for;
917 foreach my $other_trans_id ( @trans_ids ) {
918 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
920 trans_id => $other_trans_id,
922 key_md5 => $args->{key_md5},
923 value => $old_value->clone,
930 foreach my $other_trans_id ( @trans_ids ) {
931 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
932 $blist->mark_deleted({
933 trans_id => $other_trans_id,
940 # Free the place we're about to write to.
941 if ( $blist->get_data_location_for({ allow_head => 0 }) ) {
942 $blist->get_data_for({ allow_head => 0 })->free;
947 key_md5 => $args->{key_md5},
948 value => $args->{value},
956 # XXX What should happen if this fails?
957 my $blist = $self->get_bucket_list({
958 key_md5 => $args->{key_md5},
959 }) or die "How did delete_key fail (no blist)?!\n";
961 return $blist->delete_md5( $args );
967 my $e = $self->engine;
968 my $blist_loc = $e->storage->read_at( $self->offset + 2, $e->byte_size );
969 return unpack( $StP{$e->byte_size}, $blist_loc );
972 sub get_bucket_list {
977 # XXX Add in check here for recycling?
979 my $engine = $self->engine;
981 my $blist_loc = $self->get_blist_loc;
983 # There's no index or blist yet
984 unless ( $blist_loc ) {
985 return unless $args->{create};
987 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
989 key_md5 => $args->{key_md5},
992 $engine->storage->print_at( $self->offset + 2,
993 pack( $StP{$engine->byte_size}, $blist->offset ),
999 return DBM::Deep::Engine::Sector::BucketList->new({
1001 offset => $blist_loc,
1002 key_md5 => $args->{key_md5},
1009 my $class_offset = $self->engine->storage->read_at(
1010 $self->offset + 2 + 1 * $self->engine->byte_size, $self->engine->byte_size,
1012 $class_offset = unpack ( $StP{$self->engine->byte_size}, $class_offset );
1014 return unless $class_offset;
1016 return $self->engine->_load_sector( $class_offset )->data;
1022 my $new_obj = DBM::Deep->new({
1023 type => $self->type,
1024 base_offset => $self->offset,
1025 storage => $self->engine->storage,
1026 engine => $self->engine,
1029 if ( $self->engine->storage->{autobless} ) {
1030 my $classname = $self->get_classname;
1031 if ( defined $classname ) {
1032 bless $new_obj, $classname;
1039 package DBM::Deep::Engine::Sector::BucketList;
1041 our @ISA = qw( DBM::Deep::Engine::Sector );
1043 sub idx_for_txn { return $_[1] + 1 }
1048 my $engine = $self->engine;
1050 unless ( $self->offset ) {
1051 my $leftover = $self->size - $self->base_size;
1053 $self->{offset} = $engine->_request_sector( $self->size );
1054 $engine->storage->print_at( $self->offset,
1055 $engine->SIG_BLIST, # Sector type
1056 pack( $StP{1}, 0 ), # Recycled counter
1057 chr(0) x $leftover, # Zero-fill the data
1061 if ( $self->{key_md5} ) {
1068 sub base_size { 2 } # Sig + recycled counter
1072 unless ( $self->{size} ) {
1073 my $e = $self->engine;
1074 $self->{size} = $self->base_size + $e->max_buckets * $self->bucket_size; # Base + numbuckets * bucketsize
1076 return $self->{size};
1081 unless ( $self->{bucket_size} ) {
1082 my $e = $self->engine;
1083 # Key + transactions
1084 my $locs_size = (1 + $e->num_txns ) * $e->byte_size;
1085 $self->{bucket_size} = $e->hash_size + $locs_size;
1087 return $self->{bucket_size};
1092 unless ( exists $self->{found} ) {
1095 return $self->{found};
1101 $self->{found} = undef;
1104 # If we don't have an MD5, then what are we supposed to do?
1105 unless ( exists $self->{key_md5} ) {
1106 DBM::Deep->throw( "Cannot find_md5 without a key_md5 set" );
1109 my $e = $self->engine;
1110 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
1111 my $potential = $e->storage->read_at(
1112 $self->offset + $self->base_size + $idx * $self->bucket_size, $e->hash_size,
1115 if ( $potential eq $e->blank_md5 ) {
1116 $self->{idx} = $idx;
1120 if ( $potential eq $self->{key_md5} ) {
1122 $self->{idx} = $idx;
1135 $args->{trans_id} = $self->engine->trans_id unless exists $args->{trans_id};
1137 my $engine = $self->engine;
1138 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1140 unless ($self->{found}) {
1141 my $key_sector = DBM::Deep::Engine::Sector::Scalar->new({
1142 engine => $self->engine,
1143 data => $args->{key},
1146 $engine->storage->print_at( $spot,
1148 pack( $StP{$self->engine->byte_size}, $key_sector->offset ),
1152 $engine->storage->print_at(
1154 + $engine->hash_size
1155 + $engine->byte_size
1156 + $args->{trans_id} * $engine->byte_size,
1157 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
1165 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1166 $self->engine->storage->print_at(
1168 + $self->engine->hash_size
1169 + $self->engine->byte_size
1170 + $args->{trans_id} * $self->engine->byte_size,
1171 pack( $StP{$self->engine->byte_size}, 1 ), # 1 is the marker for deleted
1179 my $engine = $self->engine;
1180 return undef unless $self->{found};
1182 # Save the location so that we can free the data
1183 my $location = $self->get_data_location_for({
1186 my $key_sector = $self->get_key_for;
1188 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1189 $engine->storage->print_at( $spot,
1190 $engine->storage->read_at(
1191 $spot + $self->bucket_size,
1192 $self->bucket_size * ( $engine->num_txns - $self->{idx} - 1 ),
1194 chr(0) x $self->bucket_size,
1199 my $data_sector = $self->engine->_load_sector( $location );
1200 my $data = $data_sector->data;
1206 sub get_data_location_for {
1211 $args->{allow_head} = 0 unless exists $args->{allow_head};
1212 $args->{trans_id} = $self->engine->trans_id unless exists $args->{trans_id};
1213 $args->{idx} = $self->{idx} unless exists $args->{idx};
1215 my $location = $self->engine->storage->read_at(
1216 $self->offset + $self->base_size
1217 + $args->{idx} * $self->bucket_size
1218 + $self->engine->hash_size
1219 + $self->engine->byte_size
1220 + $args->{trans_id} * $self->engine->byte_size,
1221 $self->engine->byte_size,
1223 my $loc = unpack( $StP{$self->engine->byte_size}, $location );
1225 # If we're in a transaction and we never wrote to this location, try the
1227 if ( $args->{trans_id} && !$loc && $args->{allow_head} ) {
1228 return $self->get_data_location_for({
1233 return $loc <= 1 ? 0 : $loc;
1241 return unless $self->{found};
1242 my $location = $self->get_data_location_for({
1243 allow_head => $args->{allow_head},
1245 return $self->engine->_load_sector( $location );
1251 $idx = $self->{idx} unless defined $idx;
1253 my $location = $self->engine->storage->read_at(
1254 $self->offset + $self->base_size + $idx * $self->bucket_size + $self->engine->hash_size,
1255 $self->engine->byte_size,
1257 $location = unpack( $StP{$self->engine->byte_size}, $location );
1258 return unless $location;
1259 return $self->engine->_load_sector( $location );