1 package DBM::Deep::Engine;
8 our $VERSION = q(0.99_01);
10 use Fcntl qw( :DEFAULT :flock );
14 # * To add to bucket_size, make sure you modify the following:
17 # - add_bucket() - where the buckets are printed
20 # Setup file and tag signatures. These should never change.
22 sub SIG_FILE () { 'DPDB' }
23 sub SIG_HEADER () { 'h' }
24 sub SIG_INTERNAL () { 'i' }
25 sub SIG_HASH () { 'H' }
26 sub SIG_ARRAY () { 'A' }
27 sub SIG_NULL () { 'N' }
28 sub SIG_DATA () { 'D' }
29 sub SIG_INDEX () { 'I' }
30 sub SIG_BLIST () { 'B' }
31 sub SIG_FREE () { 'F' }
32 sub SIG_KEYS () { 'K' }
45 digest => \&Digest::MD5::md5,
49 # Maximum number of buckets per blist before another level of indexing is
50 # done. Increase this value for slightly greater speed, but larger database
51 # files. DO NOT decrease this value below 16, due to risk of recursive
60 if ( defined $args->{pack_size} ) {
61 if ( lc $args->{pack_size} eq 'small' ) {
62 $args->{long_size} = 2;
63 $args->{long_pack} = 'n';
65 elsif ( lc $args->{pack_size} eq 'medium' ) {
66 $args->{long_size} = 4;
67 $args->{long_pack} = 'N';
69 elsif ( lc $args->{pack_size} eq 'large' ) {
70 $args->{long_size} = 8;
71 $args->{long_pack} = 'Q';
74 die "Unknown pack_size value: '$args->{pack_size}'\n";
78 # Grab the parameters we want to use
79 foreach my $param ( keys %$self ) {
80 next unless exists $args->{$param};
81 $self->{$param} = $args->{$param};
83 Scalar::Util::weaken( $self->{obj} ) if $self->{obj};
85 if ( $self->{max_buckets} < 16 ) {
86 warn "Floor of max_buckets is 16. Setting it to 16 from '$self->{max_buckets}'\n";
87 $self->{max_buckets} = 16;
93 sub _fileobj { return $_[0]{fileobj} }
98 # The 2**8 here indicates the number of different characters in the
99 # current hashing algorithm
100 #XXX Does this need to be updated with different hashing algorithms?
101 $self->{hash_chars_used} = (2**8);
102 $self->{index_size} = $self->{hash_chars_used} * $self->{long_size};
104 $self->{bucket_size} = $self->{hash_size} + $self->{long_size} * 2;
105 $self->{bucket_list_size} = $self->{max_buckets} * $self->{bucket_size};
107 $self->{key_size} = $self->{long_size} * 2;
108 $self->{keyloc_size} = $self->{max_buckets} * $self->{key_size};
113 sub write_file_header {
116 my $loc = $self->_fileobj->request_space( length( SIG_FILE ) + 33 );
118 $self->_fileobj->print_at( $loc,
121 pack('N', 1), # header version
122 pack('N', 24), # header size
123 pack('N4', 0, 0, 0, 0), # currently running transaction IDs
124 pack('n', $self->{long_size}),
125 pack('A', $self->{long_pack}),
126 pack('n', $self->{data_size}),
127 pack('A', $self->{data_pack}),
128 pack('n', $self->{max_buckets}),
131 $self->_fileobj->set_transaction_offset( 13 );
136 sub read_file_header {
139 my $buffer = $self->_fileobj->read_at( 0, length(SIG_FILE) + 9 );
140 return unless length($buffer);
142 my ($file_signature, $sig_header, $header_version, $size) = unpack(
146 unless ( $file_signature eq SIG_FILE ) {
147 $self->_fileobj->close;
148 $self->_throw_error( "Signature not found -- file is not a Deep DB" );
151 unless ( $sig_header eq SIG_HEADER ) {
152 $self->_fileobj->close;
153 $self->_throw_error( "Old file version found." );
156 my $buffer2 = $self->_fileobj->read_at( undef, $size );
157 my ($a1, $a2, $a3, $a4, @values) = unpack( 'N4 n A n A n', $buffer2 );
159 $self->_fileobj->set_transaction_offset( 13 );
161 if ( @values < 5 || grep { !defined } @values ) {
162 $self->_fileobj->close;
163 $self->_throw_error("Corrupted file - bad header");
166 #XXX Add warnings if values weren't set right
167 @{$self}{qw(long_size long_pack data_size data_pack max_buckets)} = @values;
169 return length($buffer) + length($buffer2);
176 # Need to remove use of $fh here
177 my $fh = $self->_fileobj->{fh};
180 #XXX The duplication of calculate_sizes needs to go away
181 unless ( $obj->{base_offset} ) {
182 my $bytes_read = $self->read_file_header;
184 $self->calculate_sizes;
187 # File is empty -- write header and master index
190 $self->_fileobj->audit( "# Database created on" );
192 $self->write_file_header;
194 $obj->{base_offset} = $self->_fileobj->request_space(
195 $self->tag_size( $self->{index_size} ),
199 $obj->_base_offset, $obj->_type,
200 chr(0)x$self->{index_size},
203 # Flush the filehandle
204 my $old_fh = select $fh;
205 my $old_af = $|; $| = 1; $| = $old_af;
209 $obj->{base_offset} = $bytes_read;
212 # Get our type from master index header
214 my $tag = $self->load_tag($obj->_base_offset);
217 $self->_throw_error("Corrupted file, no master index record");
220 unless ($obj->_type eq $tag->{signature}) {
222 $self->_throw_error("File type mismatch");
227 $self->calculate_sizes;
230 #XXX We have to make sure we don't mess up when autoflush isn't turned on
231 $self->_fileobj->set_inode;
241 return SIG_SIZE + $self->{data_size} + $size;
246 # Given offset, signature and content, create tag and write to disk
249 my ($offset, $sig, $content) = @_;
250 my $size = length( $content );
252 $self->_fileobj->print_at(
254 $sig, pack($self->{data_pack}, $size), $content,
257 return unless defined $offset;
261 #XXX Is this even used?
263 offset => $offset + SIG_SIZE + $self->{data_size},
270 # Given offset, load single tag and return signature, size and data
275 my $fileobj = $self->_fileobj;
277 my ($sig, $size) = unpack(
278 "A $self->{data_pack}",
279 $fileobj->read_at( $offset, SIG_SIZE + $self->{data_size} ),
284 #XXX Is this even used?
286 offset => $offset + SIG_SIZE + $self->{data_size},
287 content => $fileobj->read_at( undef, $size ),
293 my ($tag, $transaction_id) = @_;
294 $transaction_id = $self->_fileobj->transaction_id
295 unless defined $transaction_id;
297 for ( my $i = 0; $i < $self->{max_buckets}; $i++ ) {
298 my ($loc, $trans_id, $is_deleted) = unpack(
299 "$self->{long_pack} C C",
300 substr( $tag->{content}, $i * $self->{key_size}, $self->{key_size} ),
304 return ( $loc, $is_deleted, $i * $self->{key_size} );
307 next if $transaction_id != $trans_id;
309 return ( $loc, $is_deleted, $i * $self->{key_size} );
317 # Adds one key/value pair to bucket list, given offset, MD5 digest of key,
318 # plain (undigested) key and value.
321 my ($tag, $md5, $plain_key, $value, $deleted, $orig_key) = @_;
323 # This verifies that only supported values will be stored.
325 my $r = Scalar::Util::reftype( $value );
328 last if $r eq 'HASH';
329 last if $r eq 'ARRAY';
332 "Storage of references of type '$r' is not supported."
336 my $fileobj = $self->_fileobj;
338 #ACID - This is a mutation. Must only find the exact transaction
339 my ($keyloc, $offset) = $self->_find_in_buckets( $tag, $md5, 1 );
342 if ( $fileobj->transaction_id == 0 ) {
343 @transactions = $fileobj->current_transactions;
346 # $self->_release_space( $size, $subloc );
347 #XXX This needs updating to use _release_space
350 my $size = $self->_length_needed( $value, $plain_key );
352 # Updating a known md5
354 my $keytag = $self->load_tag( $keyloc );
355 my ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
357 if ( @transactions ) {
358 my $old_value = $self->read_from_loc( $subloc, $orig_key );
359 my $old_size = $self->_length_needed( $old_value, $plain_key );
361 for my $trans_id ( @transactions ) {
362 my ($loc, $is_deleted, $offset2) = $self->find_keyloc( $keytag, $trans_id );
364 my $location2 = $fileobj->request_space( $old_size );
365 $fileobj->print_at( $keytag->{offset} + $offset2,
366 pack($self->{long_pack}, $location2 ),
367 pack( 'C C', $trans_id, 0 ),
369 $self->write_value( $location2, $plain_key, $old_value, $orig_key );
374 $location = $self->_fileobj->request_space( $size );
375 #XXX This needs to be transactionally-aware in terms of which keytag->{offset} to use
376 $fileobj->print_at( $keytag->{offset} + $offset,
377 pack($self->{long_pack}, $location ),
378 pack( 'C C', $fileobj->transaction_id, 0 ),
383 my $keyloc = $fileobj->request_space( $self->tag_size( $self->{keyloc_size} ) );
385 # The bucket fit into list
386 if ( defined $offset ) {
387 $fileobj->print_at( $tag->{offset} + $offset,
388 $md5, pack( $self->{long_pack}, $keyloc ),
391 # If bucket didn't fit into list, split into a new index level
393 $self->split_index( $tag, $md5, $keyloc );
396 my $keytag = $self->write_tag(
397 $keyloc, SIG_KEYS, chr(0)x$self->{keyloc_size},
400 $location = $self->_fileobj->request_space( $size );
401 $fileobj->print_at( $keytag->{offset},
402 pack( $self->{long_pack}, $location ),
403 pack( 'C C', $fileobj->transaction_id, 0 ),
407 for my $trans_id ( @transactions ) {
408 $fileobj->print_at( $keytag->{offset} + $self->{key_size} * $offset++,
409 pack( $self->{long_pack}, -1 ),
410 pack( 'C C', $trans_id, 1 ),
415 $self->write_value( $location, $plain_key, $value, $orig_key );
422 my ($location, $key, $value, $orig_key) = @_;
424 my $fileobj = $self->_fileobj;
426 my $dbm_deep_obj = _get_dbm_object( $value );
427 if ( $dbm_deep_obj && $dbm_deep_obj->_fileobj ne $fileobj ) {
428 $self->_throw_error( "Cannot cross-reference. Use export() instead" );
432 # Write signature based on content type, set content length and write
435 my $r = Scalar::Util::reftype( $value ) || '';
436 if ( $dbm_deep_obj ) {
437 $self->write_tag( $location, SIG_INTERNAL,pack($self->{long_pack}, $dbm_deep_obj->_base_offset) );
439 elsif ($r eq 'HASH') {
440 if ( !$dbm_deep_obj && tied %{$value} ) {
441 $self->_throw_error( "Cannot store something that is tied" );
443 $self->write_tag( $location, SIG_HASH, chr(0)x$self->{index_size} );
445 elsif ($r eq 'ARRAY') {
446 if ( !$dbm_deep_obj && tied @{$value} ) {
447 $self->_throw_error( "Cannot store something that is tied" );
449 $self->write_tag( $location, SIG_ARRAY, chr(0)x$self->{index_size} );
451 elsif (!defined($value)) {
452 $self->write_tag( $location, SIG_NULL, '' );
455 $self->write_tag( $location, SIG_DATA, $value );
459 # Plain key is stored AFTER value, as keys are typically fetched less often.
461 $fileobj->print_at( undef, pack($self->{data_pack}, length($key)) . $key );
463 # Internal references don't care about autobless
464 return 1 if $dbm_deep_obj;
467 # If value is blessed, preserve class name
469 if ( $fileobj->{autobless} ) {
470 if ( defined( my $c = Scalar::Util::blessed($value) ) ) {
471 $fileobj->print_at( undef, chr(1), pack($self->{data_pack}, length($c)) . $c );
474 $fileobj->print_at( undef, chr(0) );
479 # Tie the passed in reference so that changes to it are reflected in the
480 # datafile. The use of $location as the base_offset will act as the
481 # the linkage between parent and child.
483 # The overall assignment is a hack around the fact that just tying doesn't
484 # store the values. This may not be the wrong thing to do.
488 tie %$value, 'DBM::Deep', {
489 base_offset => $location,
491 parent => $self->{obj},
492 parent_key => $orig_key,
496 elsif ($r eq 'ARRAY') {
498 tie @$value, 'DBM::Deep', {
499 base_offset => $location,
501 parent => $self->{obj},
502 parent_key => $orig_key,
512 my ($tag, $md5, $keyloc) = @_;
514 my $fileobj = $self->_fileobj;
516 my $loc = $fileobj->request_space(
517 $self->tag_size( $self->{index_size} ),
520 $fileobj->print_at( $tag->{ref_loc}, pack($self->{long_pack}, $loc) );
522 my $index_tag = $self->write_tag(
524 chr(0)x$self->{index_size},
527 my $keys = $tag->{content}
528 . $md5 . pack($self->{long_pack}, $keyloc);
532 # The <= here is deliberate - we have max_buckets+1 keys to iterate
533 # through, unlike every other loop that uses max_buckets as a stop.
534 for (my $i = 0; $i <= $self->{max_buckets}; $i++) {
535 my ($key, $old_subloc) = $self->_get_key_subloc( $keys, $i );
537 die "[INTERNAL ERROR]: No key in split_index()\n" unless $key;
538 die "[INTERNAL ERROR]: No subloc in split_index()\n" unless $old_subloc;
540 my $num = ord(substr($key, $tag->{ch} + 1, 1));
543 my $subkeys = $fileobj->read_at( $newloc[$num], $self->{bucket_list_size} );
545 # This is looking for the first empty spot
546 my ($subloc, $offset) = $self->_find_in_buckets(
547 { content => $subkeys }, '',
551 $newloc[$num] + $offset,
552 $key, pack($self->{long_pack}, $old_subloc),
558 my $loc = $fileobj->request_space(
559 $self->tag_size( $self->{bucket_list_size} ),
563 $index_tag->{offset} + ($num * $self->{long_size}),
564 pack($self->{long_pack}, $loc),
567 my $blist_tag = $self->write_tag(
569 chr(0)x$self->{bucket_list_size},
572 $fileobj->print_at( $blist_tag->{offset}, $key . pack($self->{long_pack}, $old_subloc) );
574 $newloc[$num] = $blist_tag->{offset};
577 $self->_release_space(
578 $self->tag_size( $self->{bucket_list_size} ),
579 $tag->{offset} - SIG_SIZE - $self->{data_size},
587 my ($subloc, $orig_key) = @_;
589 my $fileobj = $self->_fileobj;
591 my $signature = $fileobj->read_at( $subloc, SIG_SIZE );
594 # If value is a hash or array, return new DBM::Deep object with correct offset
596 if (($signature eq SIG_HASH) || ($signature eq SIG_ARRAY)) {
597 my $new_obj = DBM::Deep->new({
599 base_offset => $subloc,
600 fileobj => $self->_fileobj,
601 parent => $self->{obj},
602 parent_key => $orig_key,
605 if ($new_obj->_fileobj->{autobless}) {
607 # Skip over value and plain key to see if object needs
610 $fileobj->increment_pointer( $self->{data_size} + $self->{index_size} );
612 my $size = $fileobj->read_at( undef, $self->{data_size} );
613 $size = unpack($self->{data_pack}, $size);
614 if ($size) { $fileobj->increment_pointer( $size ); }
616 my $bless_bit = $fileobj->read_at( undef, 1 );
617 if ( ord($bless_bit) ) {
620 $fileobj->read_at( undef, $self->{data_size} ),
624 $new_obj = bless $new_obj, $fileobj->read_at( undef, $size );
631 elsif ( $signature eq SIG_INTERNAL ) {
632 my $size = $fileobj->read_at( undef, $self->{data_size} );
633 $size = unpack($self->{data_pack}, $size);
636 my $new_loc = $fileobj->read_at( undef, $size );
637 $new_loc = unpack( $self->{long_pack}, $new_loc );
638 return $self->read_from_loc( $new_loc, $orig_key );
645 # Otherwise return actual value
647 elsif ( $signature eq SIG_DATA ) {
648 my $size = $fileobj->read_at( undef, $self->{data_size} );
649 $size = unpack($self->{data_pack}, $size);
651 my $value = $size ? $fileobj->read_at( undef, $size ) : '';
656 # Key exists, but content is null
661 sub get_bucket_value {
663 # Fetch single value given tag and MD5 digested key.
666 my ($tag, $md5, $orig_key) = @_;
668 #ACID - This is a read. Can find exact or HEAD
669 my ($keyloc, $offset) = $self->_find_in_buckets( $tag, $md5 );
672 #XXX Need to use real key
673 # $self->add_bucket( $tag, $md5, $orig_key, undef, $orig_key );
676 # elsif ( !$is_deleted ) {
678 my $keytag = $self->load_tag( $keyloc );
679 my ($subloc, $is_deleted) = $self->find_keyloc( $keytag );
681 ($subloc, $is_deleted) = $self->find_keyloc( $keytag, 0 );
683 if ( $subloc && !$is_deleted ) {
684 return $self->read_from_loc( $subloc, $orig_key );
693 # Delete single key/value pair given tag and MD5 digested key.
696 my ($tag, $md5, $orig_key) = @_;
698 #ACID - Although this is a mutation, we must find any transaction.
699 # This is because we need to mark something as deleted that is in the HEAD.
700 my ($keyloc, $offset) = $self->_find_in_buckets( $tag, $md5 );
704 my $fileobj = $self->_fileobj;
707 if ( $fileobj->transaction_id == 0 ) {
708 @transactions = $fileobj->current_transactions;
711 if ( $fileobj->transaction_id == 0 ) {
712 my $keytag = $self->load_tag( $keyloc );
713 my ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
714 my $value = $self->read_from_loc( $subloc, $orig_key );
716 my $size = $self->_length_needed( $value, $orig_key );
718 for my $trans_id ( @transactions ) {
719 my ($loc, $is_deleted, $offset2) = $self->find_keyloc( $keytag, $trans_id );
721 my $location2 = $fileobj->request_space( $size );
722 $fileobj->print_at( $keytag->{offset} + $offset2,
723 pack($self->{long_pack}, $location2 ),
724 pack( 'C C', $trans_id, 0 ),
726 $self->write_value( $location2, $orig_key, $value, $orig_key );
730 $keytag = $self->load_tag( $keyloc );
731 ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
732 $fileobj->print_at( $keytag->{offset} + $offset,
733 substr( $keytag->{content}, $offset + $self->{key_size} ),
734 chr(0) x $self->{key_size},
738 my $keytag = $self->load_tag( $keyloc );
739 my ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
740 $fileobj->print_at( $keytag->{offset} + $offset,
741 pack($self->{long_pack}, -1 ),
742 pack( 'C C', $fileobj->transaction_id, 1 ),
751 # Check existence of single key given tag and MD5 digested key.
754 my ($tag, $md5) = @_;
756 #ACID - This is a read. Can find exact or HEAD
757 my ($keyloc) = $self->_find_in_buckets( $tag, $md5 );
758 my $keytag = $self->load_tag( $keyloc );
759 my ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
761 ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag, 0 );
763 return ($subloc && !$is_deleted) && 1;
768 # Locate offset for bucket list, given digested key
771 my ($offset, $md5, $args) = @_;
772 $args = {} unless $args;
775 # Locate offset for bucket list using digest index system
777 my $tag = $self->load_tag( $offset )
778 or $self->_throw_error( "INTERNAL ERROR - Cannot find tag" );
781 while ($tag->{signature} ne SIG_BLIST) {
782 my $num = ord substr($md5, $ch, 1);
784 my $ref_loc = $tag->{offset} + ($num * $self->{long_size});
785 $tag = $self->index_lookup( $tag, $num );
788 return if !$args->{create};
790 my $loc = $self->_fileobj->request_space(
791 $self->tag_size( $self->{bucket_list_size} ),
794 $self->_fileobj->print_at( $ref_loc, pack($self->{long_pack}, $loc) );
796 $tag = $self->write_tag(
798 chr(0)x$self->{bucket_list_size},
801 $tag->{ref_loc} = $ref_loc;
808 $tag->{ref_loc} = $ref_loc;
816 # Given index tag, lookup single entry in index and return .
819 my ($tag, $index) = @_;
821 my $location = unpack(
825 $index * $self->{long_size},
830 if (!$location) { return; }
832 return $self->load_tag( $location );
837 # Scan index and recursively step into deeper levels, looking for next key.
840 my ($xxxx, $offset, $ch, $force_return_next) = @_;
842 my $tag = $self->load_tag( $offset );
844 if ($tag->{signature} ne SIG_BLIST) {
845 my $start = $xxxx->{return_next} ? 0 : ord(substr($xxxx->{prev_md5}, $ch, 1));
847 for (my $idx = $start; $idx < $self->{hash_chars_used}; $idx++) {
852 $idx * $self->{long_size},
858 my $result = $self->traverse_index(
859 $xxxx, $subloc, $ch + 1, $force_return_next,
862 if (defined $result) { return $result; }
866 $xxxx->{return_next} = 1;
868 # This is the bucket list
870 my $keys = $tag->{content};
871 if ($force_return_next) { $xxxx->{return_next} = 1; }
874 # Iterate through buckets, looking for a key match
876 my $transaction_id = $self->_fileobj->transaction_id;
877 for (my $i = 0; $i < $self->{max_buckets}; $i++) {
878 my ($key, $keyloc) = $self->_get_key_subloc( $keys, $i );
880 # End of bucket list -- return to outer loop
882 $xxxx->{return_next} = 1;
885 # Located previous key -- return next one found
886 elsif ($key eq $xxxx->{prev_md5}) {
887 $xxxx->{return_next} = 1;
890 # Seek to bucket location and skip over signature
891 elsif ($xxxx->{return_next}) {
892 my $fileobj = $self->_fileobj;
894 my $keytag = $self->load_tag( $keyloc );
895 my ($subloc, $is_deleted) = $self->find_keyloc( $keytag );
896 if ( $subloc == 0 ) {
897 ($subloc, $is_deleted) = $self->find_keyloc( $keytag, 0 );
901 # Skip over value to get to plain key
902 my $sig = $fileobj->read_at( $subloc, SIG_SIZE );
904 my $size = $fileobj->read_at( undef, $self->{data_size} );
905 $size = unpack($self->{data_pack}, $size);
906 if ($size) { $fileobj->increment_pointer( $size ); }
908 # Read in plain key and return as scalar
909 $size = $fileobj->read_at( undef, $self->{data_size} );
910 $size = unpack($self->{data_pack}, $size);
913 if ($size) { $plain_key = $fileobj->read_at( undef, $size); }
918 $xxxx->{return_next} = 1;
926 # Locate next key, given digested previous one
932 # If the previous key was not specifed, start at the top and
933 # return the first one found.
944 prev_md5 => chr(0) x $self->{hash_size},
949 return $self->traverse_index( $temp, $obj->_base_offset, 0 );
954 sub _get_key_subloc {
956 my ($keys, $idx) = @_;
959 # This is 'a', not 'A'. Please read the pack() documentation for the
960 # difference between the two and why it's important.
961 "a$self->{hash_size} $self->{long_pack}",
964 ($idx * $self->{bucket_size}),
965 $self->{bucket_size},
970 sub _find_in_buckets {
972 my ($tag, $md5) = @_;
975 for ( my $i = 0; $i < $self->{max_buckets}; $i++ ) {
976 my ($key, $subloc) = $self->_get_key_subloc(
980 my @rv = ($subloc, $i * $self->{bucket_size});
986 next BUCKET if $key ne $md5;
996 my ($size, $loc) = @_;
1000 $self->_fileobj->print_at( $loc,
1002 pack($self->{long_pack}, $size ),
1003 pack($self->{long_pack}, $next_loc ),
1010 die "DBM::Deep: $_[1]\n";
1013 sub _get_dbm_object {
1017 local $SIG{__DIE__};
1018 if ($item->isa( 'DBM::Deep' )) {
1023 return $obj if $obj;
1025 my $r = Scalar::Util::reftype( $item ) || '';
1026 if ( $r eq 'HASH' ) {
1028 local $SIG{__DIE__};
1029 my $obj = tied(%$item);
1030 if ($obj->isa( 'DBM::Deep' )) {
1035 return $obj if $obj;
1037 elsif ( $r eq 'ARRAY' ) {
1039 local $SIG{__DIE__};
1040 my $obj = tied(@$item);
1041 if ($obj->isa( 'DBM::Deep' )) {
1046 return $obj if $obj;
1052 sub _length_needed {
1054 my ($value, $key) = @_;
1056 my $is_dbm_deep = eval {
1057 local $SIG{'__DIE__'};
1058 $value->isa( 'DBM::Deep' );
1062 + $self->{data_size} # size for value
1063 + $self->{data_size} # size for key
1064 + length( $key ); # length of key
1066 if ( $is_dbm_deep && $value->_fileobj eq $self->_fileobj ) {
1067 # long_size is for the internal reference
1068 return $len + $self->{long_size};
1071 if ( $self->_fileobj->{autobless} ) {
1072 # This is for the bit saying whether or not this thing is blessed.
1076 my $r = Scalar::Util::reftype( $value ) || '';
1077 unless ( $r eq 'HASH' || $r eq 'ARRAY' ) {
1078 if ( defined $value ) {
1079 $len += length( $value );
1084 $len += $self->{index_size};
1086 # if autobless is enabled, must also take into consideration
1087 # the class name as it is stored after the key.
1088 if ( $self->_fileobj->{autobless} ) {
1089 my $c = Scalar::Util::blessed($value);
1090 if ( defined $c && !$is_dbm_deep ) {
1091 $len += $self->{data_size} + length($c);