1 package DBM::Deep::Engine;
7 our $VERSION = q(0.99_03);
9 use Fcntl qw( :DEFAULT :flock );
13 # * To add to bucket_size, make sure you modify the following:
16 # - add_bucket() - where the buckets are printed
18 # * Every method in here assumes that the _storage has been appropriately
19 # safeguarded. This can be anything from flock() to some sort of manual
20 # mutex. But, it's the caller's responsability to make sure that this has
24 # Setup file and tag signatures. These should never change.
26 sub SIG_FILE () { 'DPDB' }
27 sub SIG_HEADER () { 'h' }
28 sub SIG_INTERNAL () { 'i' }
29 sub SIG_HASH () { 'H' }
30 sub SIG_ARRAY () { 'A' }
31 sub SIG_NULL () { 'N' }
32 sub SIG_DATA () { 'D' }
33 sub SIG_INDEX () { 'I' }
34 sub SIG_BLIST () { 'B' }
35 sub SIG_FREE () { 'F' }
36 sub SIG_KEYS () { 'K' }
39 # This is the transaction ID for the HEAD
42 ################################################################################
44 # This is new code. It is a complete rewrite of the engine based on a new API
46 ################################################################################
50 my ($trans_id, $offset, $key, $orig_key) = @_;
52 my $dig_key = $self->_apply_digest( $key );
53 my $tag = $self->find_blist( $offset, $dig_key ) or return;
54 return $self->get_bucket_value( $tag, $dig_key, $orig_key );
59 my ($trans_id, $offset, $key) = @_;
61 my $dig_key = $self->_apply_digest( $key );
62 # exists() returns the empty string, not undef
63 my $tag = $self->find_blist( $offset, $dig_key ) or return '';
64 return $self->bucket_exists( $tag, $dig_key, $key );
69 my ($trans_id, $offset) = @_;
71 # If the previous key was not specifed, start at the top and
72 # return the first one found.
76 prev_md5 => $self->_apply_digest($_[2]),
82 prev_md5 => chr(0) x $self->{hash_size},
87 return $self->traverse_index( $temp, $offset, 0 );
92 my ($trans_id, $offset, $key, $orig_key) = @_;
94 my $dig_key = $self->_apply_digest( $key );
95 my $tag = $self->find_blist( $offset, $dig_key ) or return;
96 my $value = $self->get_bucket_value( $tag, $dig_key, $orig_key );
97 $self->delete_bucket( $tag, $dig_key, $orig_key );
103 my ($trans_id, $offset, $key, $value, $orig_key) = @_;
105 my $dig_key = $self->_apply_digest( $key );
106 my $tag = $self->find_blist( $offset, $dig_key, { create => 1 } );
107 return $self->add_bucket( $tag, $dig_key, $key, $value, undef, $orig_key );
110 ################################################################################
112 # Below here is the old code. It will be folded into the code above as it can.
114 ################################################################################
126 digest => \&Digest::MD5::md5,
127 hash_size => 16, # In bytes
130 # Number of buckets per blist before another level of indexing is
131 # done. Increase this value for slightly greater speed, but larger database
132 # files. DO NOT decrease this value below 16, due to risk of recursive
141 if ( defined $args->{pack_size} ) {
142 if ( lc $args->{pack_size} eq 'small' ) {
143 $args->{long_size} = 2;
144 $args->{long_pack} = 'n';
146 elsif ( lc $args->{pack_size} eq 'medium' ) {
147 $args->{long_size} = 4;
148 $args->{long_pack} = 'N';
150 elsif ( lc $args->{pack_size} eq 'large' ) {
151 $args->{long_size} = 8;
152 $args->{long_pack} = 'Q';
155 die "Unknown pack_size value: '$args->{pack_size}'\n";
159 # Grab the parameters we want to use
160 foreach my $param ( keys %$self ) {
161 next unless exists $args->{$param};
162 $self->{$param} = $args->{$param};
164 Scalar::Util::weaken( $self->{obj} ) if $self->{obj};
166 if ( $self->{max_buckets} < 16 ) {
167 warn "Floor of max_buckets is 16. Setting it to 16 from '$self->{max_buckets}'\n";
168 $self->{max_buckets} = 16;
174 sub _storage { return $_[0]{storage} }
178 return $self->{digest}->(@_);
181 sub calculate_sizes {
184 # The 2**8 here indicates the number of different characters in the
185 # current hashing algorithm
186 #XXX Does this need to be updated with different hashing algorithms?
187 $self->{hash_chars_used} = (2**8);
188 $self->{index_size} = $self->{hash_chars_used} * $self->{long_size};
190 $self->{bucket_size} = $self->{hash_size} + $self->{long_size} * 2;
191 $self->{bucket_list_size} = $self->{max_buckets} * $self->{bucket_size};
193 $self->{key_size} = $self->{long_size} * 2;
194 $self->{keyloc_size} = $self->{max_buckets} * $self->{key_size};
199 sub write_file_header {
202 my $loc = $self->_storage->request_space( length( SIG_FILE ) + 33 );
204 $self->_storage->print_at( $loc,
207 pack('N', 1), # header version
208 pack('N', 24), # header size
209 pack('N4', 0, 0, 0, 0), # currently running transaction IDs
210 pack('n', $self->{long_size}),
211 pack('A', $self->{long_pack}),
212 pack('n', $self->{data_size}),
213 pack('A', $self->{data_pack}),
214 pack('n', $self->{max_buckets}),
217 $self->_storage->set_transaction_offset( 13 );
222 sub read_file_header {
225 my $buffer = $self->_storage->read_at( 0, length(SIG_FILE) + 9 );
226 return unless length($buffer);
228 my ($file_signature, $sig_header, $header_version, $size) = unpack(
232 unless ( $file_signature eq SIG_FILE ) {
233 $self->_storage->close;
234 $self->_throw_error( "Signature not found -- file is not a Deep DB" );
237 unless ( $sig_header eq SIG_HEADER ) {
238 $self->_storage->close;
239 $self->_throw_error( "Old file version found." );
242 my $buffer2 = $self->_storage->read_at( undef, $size );
243 my ($a1, $a2, $a3, $a4, @values) = unpack( 'N4 n A n A n', $buffer2 );
245 $self->_storage->set_transaction_offset( 13 );
247 if ( @values < 5 || grep { !defined } @values ) {
248 $self->_storage->close;
249 $self->_throw_error("Corrupted file - bad header");
252 #XXX Add warnings if values weren't set right
253 @{$self}{qw(long_size long_pack data_size data_pack max_buckets)} = @values;
255 return length($buffer) + length($buffer2);
262 # Need to remove use of $fh here
263 my $fh = $self->_storage->{fh};
266 #XXX The duplication of calculate_sizes needs to go away
267 unless ( $obj->{base_offset} ) {
268 my $bytes_read = $self->read_file_header;
270 $self->calculate_sizes;
273 # File is empty -- write header and master index
276 $self->_storage->audit( "# Database created on" );
278 $self->write_file_header;
280 $obj->{base_offset} = $self->_storage->request_space(
281 $self->tag_size( $self->{index_size} ),
285 $obj->_base_offset, $obj->_type,
286 chr(0)x$self->{index_size},
289 # Flush the filehandle
290 my $old_fh = select $fh;
291 my $old_af = $|; $| = 1; $| = $old_af;
295 $obj->{base_offset} = $bytes_read;
298 # Get our type from master index header
300 my $tag = $self->load_tag($obj->_base_offset);
303 $self->_throw_error("Corrupted file, no master index record");
306 unless ($obj->_type eq $tag->{signature}) {
308 $self->_throw_error("File type mismatch");
313 $self->calculate_sizes;
316 #XXX We have to make sure we don't mess up when autoflush isn't turned on
317 $self->_storage->set_inode;
327 return SIG_SIZE + $self->{data_size} + $size;
332 # Given offset, signature and content, create tag and write to disk
335 my ($offset, $sig, $content) = @_;
336 my $size = length( $content );
338 $self->_storage->print_at(
340 $sig, pack($self->{data_pack}, $size), $content,
343 return unless defined $offset;
347 #XXX Is this even used?
349 offset => $offset + SIG_SIZE + $self->{data_size},
356 # Given offset, load single tag and return signature, size and data
361 my $storage = $self->_storage;
363 my ($sig, $size) = unpack(
364 "A $self->{data_pack}",
365 $storage->read_at( $offset, SIG_SIZE + $self->{data_size} ),
370 size => $size, #XXX Is this even used?
372 offset => $offset + SIG_SIZE + $self->{data_size},
373 content => $storage->read_at( undef, $size ),
379 my ($tag, $transaction_id) = @_;
380 $transaction_id = $self->_storage->transaction_id
381 unless defined $transaction_id;
383 for ( my $i = 0; $i < $self->{max_buckets}; $i++ ) {
384 my ($loc, $trans_id, $is_deleted) = unpack(
385 "$self->{long_pack} C C",
386 substr( $tag->{content}, $i * $self->{key_size}, $self->{key_size} ),
389 next if $loc != HEAD && $transaction_id != $trans_id;
390 return( $loc, $is_deleted, $i * $self->{key_size} );
398 # Adds one key/value pair to bucket list, given offset, MD5 digest of key,
399 # plain (undigested) key and value.
402 my ($tag, $md5, $plain_key, $value, $deleted, $orig_key) = @_;
404 # This verifies that only supported values will be stored.
406 my $r = Scalar::Util::reftype( $value );
409 last if $r eq 'HASH';
410 last if $r eq 'ARRAY';
413 "Storage of references of type '$r' is not supported."
417 my $storage = $self->_storage;
419 #ACID - This is a mutation. Must only find the exact transaction
420 my ($keyloc, $offset) = $self->_find_in_buckets( $tag, $md5, 1 );
423 if ( $storage->transaction_id == 0 ) {
424 @transactions = $storage->current_transactions;
427 # $self->_release_space( $size, $subloc );
428 #XXX This needs updating to use _release_space
431 my $size = $self->_length_needed( $value, $plain_key );
433 # Updating a known md5
435 my $keytag = $self->load_tag( $keyloc );
436 my ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
438 if ( $subloc && !$is_deleted && @transactions ) {
439 my $old_value = $self->read_from_loc( $subloc, $orig_key );
440 my $old_size = $self->_length_needed( $old_value, $plain_key );
442 for my $trans_id ( @transactions ) {
443 my ($loc, $is_deleted, $offset2) = $self->find_keyloc( $keytag, $trans_id );
445 my $location2 = $storage->request_space( $old_size );
446 $storage->print_at( $keytag->{offset} + $offset2,
447 pack($self->{long_pack}, $location2 ),
448 pack( 'C C', $trans_id, 0 ),
450 $self->_write_value( $location2, $plain_key, $old_value, $orig_key );
455 $location = $self->_storage->request_space( $size );
456 #XXX This needs to be transactionally-aware in terms of which keytag->{offset} to use
457 $storage->print_at( $keytag->{offset} + $offset,
458 pack($self->{long_pack}, $location ),
459 pack( 'C C', $storage->transaction_id, 0 ),
464 my $keyloc = $storage->request_space( $self->tag_size( $self->{keyloc_size} ) );
466 # The bucket fit into list
467 if ( defined $offset ) {
468 $storage->print_at( $tag->{offset} + $offset,
469 $md5, pack( $self->{long_pack}, $keyloc ),
472 # If bucket didn't fit into list, split into a new index level
474 $self->split_index( $tag, $md5, $keyloc );
477 my $keytag = $self->write_tag(
478 $keyloc, SIG_KEYS, chr(0)x$self->{keyloc_size},
481 $location = $self->_storage->request_space( $size );
482 $storage->print_at( $keytag->{offset},
483 pack( $self->{long_pack}, $location ),
484 pack( 'C C', $storage->transaction_id, 0 ),
488 for my $trans_id ( @transactions ) {
489 $storage->print_at( $keytag->{offset} + $self->{key_size} * $offset++,
490 pack( $self->{long_pack}, 0 ),
491 pack( 'C C', $trans_id, 1 ),
496 $self->_write_value( $location, $plain_key, $value, $orig_key );
503 my ($key_loc, $location, $key, $value, $orig_key) = @_;
505 my $storage = $self->_storage;
507 my $dbm_deep_obj = _get_dbm_object( $value );
508 if ( $dbm_deep_obj && $dbm_deep_obj->_storage ne $storage ) {
509 $self->_throw_error( "Cannot cross-reference. Use export() instead" );
513 # Write signature based on content type, set content length and write
516 my $r = Scalar::Util::reftype( $value ) || '';
517 if ( $dbm_deep_obj ) {
518 $self->write_tag( $location, SIG_INTERNAL,pack($self->{long_pack}, $dbm_deep_obj->_base_offset) );
520 elsif ($r eq 'HASH') {
521 if ( !$dbm_deep_obj && tied %{$value} ) {
522 $self->_throw_error( "Cannot store something that is tied" );
524 $self->write_tag( $location, SIG_HASH, chr(0)x$self->{index_size} );
526 elsif ($r eq 'ARRAY') {
527 if ( !$dbm_deep_obj && tied @{$value} ) {
528 $self->_throw_error( "Cannot store something that is tied" );
530 $self->write_tag( $location, SIG_ARRAY, chr(0)x$self->{index_size} );
532 elsif (!defined($value)) {
533 $self->write_tag( $location, SIG_NULL, '' );
536 $self->write_tag( $location, SIG_DATA, $value );
540 # Plain key is stored AFTER value, as keys are typically fetched less often.
542 $storage->print_at( undef, pack($self->{data_pack}, length($key)) . $key );
544 # Internal references don't care about autobless
545 return 1 if $dbm_deep_obj;
548 # If value is blessed, preserve class name
550 if ( $storage->{autobless} ) {
551 if ( defined( my $c = Scalar::Util::blessed($value) ) ) {
552 $storage->print_at( undef, chr(1), pack($self->{data_pack}, length($c)) . $c );
555 $storage->print_at( undef, chr(0) );
560 # Tie the passed in reference so that changes to it are reflected in the
561 # datafile. The use of $location as the base_offset will act as the
562 # the linkage between parent and child.
564 # The overall assignment is a hack around the fact that just tying doesn't
565 # store the values. This may not be the wrong thing to do.
569 tie %$value, 'DBM::Deep', {
570 base_offset => $key_loc,
572 parent => $self->{obj},
573 parent_key => $orig_key,
576 bless $value, 'DBM::Deep::Hash' unless Scalar::Util::blessed( $value );
578 elsif ($r eq 'ARRAY') {
580 tie @$value, 'DBM::Deep', {
581 base_offset => $key_loc,
583 parent => $self->{obj},
584 parent_key => $orig_key,
587 bless $value, 'DBM::Deep::Array' unless Scalar::Util::blessed( $value );
595 my ($tag, $md5, $keyloc) = @_;
597 my $storage = $self->_storage;
599 my $loc = $storage->request_space(
600 $self->tag_size( $self->{index_size} ),
603 $storage->print_at( $tag->{ref_loc}, pack($self->{long_pack}, $loc) );
605 my $index_tag = $self->write_tag(
607 chr(0)x$self->{index_size},
610 my $keys = $tag->{content}
611 . $md5 . pack($self->{long_pack}, $keyloc);
615 # The <= here is deliberate - we have max_buckets+1 keys to iterate
616 # through, unlike every other loop that uses max_buckets as a stop.
617 for (my $i = 0; $i <= $self->{max_buckets}; $i++) {
618 my ($key, $old_subloc) = $self->_get_key_subloc( $keys, $i );
620 die "[INTERNAL ERROR]: No key in split_index()\n" unless $key;
621 die "[INTERNAL ERROR]: No subloc in split_index()\n" unless $old_subloc;
623 my $num = ord(substr($key, $tag->{ch} + 1, 1));
626 my $subkeys = $storage->read_at( $newloc[$num], $self->{bucket_list_size} );
628 # This is looking for the first empty spot
629 my ($subloc, $offset) = $self->_find_in_buckets(
630 { content => $subkeys }, '',
634 $newloc[$num] + $offset,
635 $key, pack($self->{long_pack}, $old_subloc),
641 my $loc = $storage->request_space(
642 $self->tag_size( $self->{bucket_list_size} ),
646 $index_tag->{offset} + ($num * $self->{long_size}),
647 pack($self->{long_pack}, $loc),
650 my $blist_tag = $self->write_tag(
652 chr(0)x$self->{bucket_list_size},
655 $storage->print_at( $blist_tag->{offset}, $key . pack($self->{long_pack}, $old_subloc) );
657 $newloc[$num] = $blist_tag->{offset};
660 $self->_release_space(
661 $self->tag_size( $self->{bucket_list_size} ),
670 my ($key_loc, $subloc, $orig_key) = @_;
672 my $storage = $self->_storage;
674 my $signature = $storage->read_at( $subloc, SIG_SIZE );
677 # If value is a hash or array, return new DBM::Deep object with correct offset
679 if (($signature eq SIG_HASH) || ($signature eq SIG_ARRAY)) {
680 #XXX This needs to be a singleton
683 # if ( $signature eq SIG_HASH ) {
685 # tie %$new_obj, 'DBM::Deep', {
686 # base_offset => $subloc,
687 # storage => $self->_storage,
688 # parent => $self->{obj},
689 # parent_key => $orig_key,
691 # $is_autobless = tied(%$new_obj)->_storage->{autobless};
695 # tie @$new_obj, 'DBM::Deep', {
696 # base_offset => $subloc,
697 # storage => $self->_storage,
698 # parent => $self->{obj},
699 # parent_key => $orig_key,
701 # $is_autobless = tied(@$new_obj)->_storage->{autobless};
704 # if ($is_autobless) {
706 my $new_obj = DBM::Deep->new({
708 base_offset => $key_loc,
709 storage => $self->_storage,
710 parent => $self->{obj},
711 parent_key => $orig_key,
714 if ($new_obj->_storage->{autobless}) {
716 # Skip over value and plain key to see if object needs
719 $storage->increment_pointer( $self->{data_size} + $self->{index_size} );
721 my $size = $storage->read_at( undef, $self->{data_size} );
722 $size = unpack($self->{data_pack}, $size);
723 if ($size) { $storage->increment_pointer( $size ); }
725 my $bless_bit = $storage->read_at( undef, 1 );
726 if ( ord($bless_bit) ) {
729 $storage->read_at( undef, $self->{data_size} ),
733 $new_obj = bless $new_obj, $storage->read_at( undef, $size );
740 elsif ( $signature eq SIG_INTERNAL ) {
741 my $size = $storage->read_at( undef, $self->{data_size} );
742 $size = unpack($self->{data_pack}, $size);
745 my $new_loc = $storage->read_at( undef, $size );
746 $new_loc = unpack( $self->{long_pack}, $new_loc );
747 return $self->read_from_loc( $key_loc, $new_loc, $orig_key );
754 # Otherwise return actual value
756 elsif ( $signature eq SIG_DATA ) {
757 my $size = $storage->read_at( undef, $self->{data_size} );
758 $size = unpack($self->{data_pack}, $size);
760 my $value = $size ? $storage->read_at( undef, $size ) : '';
765 # Key exists, but content is null
770 sub get_bucket_value {
772 # Fetch single value given tag and MD5 digested key.
775 my ($tag, $md5, $orig_key) = @_;
777 #ACID - This is a read. Can find exact or HEAD
778 my ($keyloc, $offset) = $self->_find_in_buckets( $tag, $md5 );
781 #XXX Need to use real key
782 # $self->add_bucket( $tag, $md5, $orig_key, undef, $orig_key );
785 # elsif ( !$is_deleted ) {
787 my $keytag = $self->load_tag( $keyloc );
788 my ($subloc, $is_deleted) = $self->find_keyloc( $keytag );
789 if (!$subloc && !$is_deleted) {
790 ($subloc, $is_deleted) = $self->find_keyloc( $keytag, 0 );
792 if ( $subloc && !$is_deleted ) {
793 return $self->read_from_loc( $subloc, $orig_key );
802 # Delete single key/value pair given tag and MD5 digested key.
805 my ($tag, $md5, $orig_key) = @_;
807 #ACID - Although this is a mutation, we must find any transaction.
808 # This is because we need to mark something as deleted that is in the HEAD.
809 my ($keyloc, $offset) = $self->_find_in_buckets( $tag, $md5 );
813 my $storage = $self->_storage;
816 if ( $storage->transaction_id == 0 ) {
817 @transactions = $storage->current_transactions;
820 if ( $storage->transaction_id == 0 ) {
821 my $keytag = $self->load_tag( $keyloc );
823 my ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
824 return if !$subloc || $is_deleted;
826 my $value = $self->read_from_loc( $subloc, $orig_key );
828 my $size = $self->_length_needed( $value, $orig_key );
830 for my $trans_id ( @transactions ) {
831 my ($loc, $is_deleted, $offset2) = $self->find_keyloc( $keytag, $trans_id );
833 my $location2 = $storage->request_space( $size );
834 $storage->print_at( $keytag->{offset} + $offset2,
835 pack($self->{long_pack}, $location2 ),
836 pack( 'C C', $trans_id, 0 ),
838 $self->_write_value( $location2, $orig_key, $value, $orig_key );
842 $keytag = $self->load_tag( $keyloc );
843 ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
844 $storage->print_at( $keytag->{offset} + $offset,
845 substr( $keytag->{content}, $offset + $self->{key_size} ),
846 chr(0) x $self->{key_size},
850 my $keytag = $self->load_tag( $keyloc );
852 my ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
854 $storage->print_at( $keytag->{offset} + $offset,
855 pack($self->{long_pack}, 0 ),
856 pack( 'C C', $storage->transaction_id, 1 ),
865 # Check existence of single key given tag and MD5 digested key.
868 my ($tag, $md5) = @_;
870 #ACID - This is a read. Can find exact or HEAD
871 my ($keyloc) = $self->_find_in_buckets( $tag, $md5 );
872 my $keytag = $self->load_tag( $keyloc );
873 my ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
874 if ( !$subloc && !$is_deleted ) {
875 ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag, 0 );
877 return ($subloc && !$is_deleted) && 1;
882 # Locate offset for bucket list, given digested key
885 my ($offset, $md5, $args) = @_;
886 $args = {} unless $args;
889 # Locate offset for bucket list using digest index system
891 my $tag = $self->load_tag( $offset )
892 or $self->_throw_error( "INTERNAL ERROR - Cannot find tag" );
894 #XXX What happens when $ch >= $self->{hash_size} ??
895 for (my $ch = 0; $tag->{signature} ne SIG_BLIST; $ch++) {
896 my $num = ord substr($md5, $ch, 1);
898 my $ref_loc = $tag->{offset} + ($num * $self->{long_size});
899 $tag = $self->index_lookup( $tag, $num );
902 return if !$args->{create};
904 my $loc = $self->_storage->request_space(
905 $self->tag_size( $self->{bucket_list_size} ),
908 $self->_storage->print_at( $ref_loc, pack($self->{long_pack}, $loc) );
910 $tag = $self->write_tag(
912 chr(0)x$self->{bucket_list_size},
915 $tag->{ref_loc} = $ref_loc;
922 $tag->{ref_loc} = $ref_loc;
930 # Given index tag, lookup single entry in index and return .
933 my ($tag, $index) = @_;
935 my $location = unpack(
939 $index * $self->{long_size},
944 if (!$location) { return; }
946 return $self->load_tag( $location );
951 # Scan index and recursively step into deeper levels, looking for next key.
954 my ($xxxx, $offset, $ch, $force_return_next) = @_;
956 my $tag = $self->load_tag( $offset );
958 if ($tag->{signature} ne SIG_BLIST) {
959 my $start = $xxxx->{return_next} ? 0 : ord(substr($xxxx->{prev_md5}, $ch, 1));
961 for (my $idx = $start; $idx < $self->{hash_chars_used}; $idx++) {
966 $idx * $self->{long_size},
972 my $result = $self->traverse_index(
973 $xxxx, $subloc, $ch + 1, $force_return_next,
976 if (defined $result) { return $result; }
980 $xxxx->{return_next} = 1;
982 # This is the bucket list
984 my $keys = $tag->{content};
985 if ($force_return_next) { $xxxx->{return_next} = 1; }
988 # Iterate through buckets, looking for a key match
990 my $transaction_id = $self->_storage->transaction_id;
991 for (my $i = 0; $i < $self->{max_buckets}; $i++) {
992 my ($key, $keyloc) = $self->_get_key_subloc( $keys, $i );
994 # End of bucket list -- return to outer loop
996 $xxxx->{return_next} = 1;
999 # Located previous key -- return next one found
1000 elsif ($key eq $xxxx->{prev_md5}) {
1001 $xxxx->{return_next} = 1;
1004 # Seek to bucket location and skip over signature
1005 elsif ($xxxx->{return_next}) {
1006 my $storage = $self->_storage;
1008 my $keytag = $self->load_tag( $keyloc );
1009 my ($subloc, $is_deleted) = $self->find_keyloc( $keytag );
1010 if ( $subloc == 0 && !$is_deleted ) {
1011 ($subloc, $is_deleted) = $self->find_keyloc( $keytag, 0 );
1013 next if $is_deleted;
1015 # Skip over value to get to plain key
1016 my $sig = $storage->read_at( $subloc, SIG_SIZE );
1018 my $size = $storage->read_at( undef, $self->{data_size} );
1019 $size = unpack($self->{data_pack}, $size);
1020 if ($size) { $storage->increment_pointer( $size ); }
1022 # Read in plain key and return as scalar
1023 $size = $storage->read_at( undef, $self->{data_size} );
1024 $size = unpack($self->{data_pack}, $size);
1027 if ($size) { $plain_key = $storage->read_at( undef, $size); }
1032 $xxxx->{return_next} = 1;
1040 sub _get_key_subloc {
1042 my ($keys, $idx) = @_;
1045 # This is 'a', not 'A'. Please read the pack() documentation for the
1046 # difference between the two and why it's important.
1047 "a$self->{hash_size} $self->{long_pack}",
1050 ($idx * $self->{bucket_size}),
1051 $self->{bucket_size},
1056 sub _find_in_buckets {
1058 my ($tag, $md5) = @_;
1061 for ( my $i = 0; $i < $self->{max_buckets}; $i++ ) {
1062 my ($key, $subloc) = $self->_get_key_subloc(
1063 $tag->{content}, $i,
1066 next BUCKET if $subloc && $key ne $md5;
1067 return( $subloc, $i * $self->{bucket_size} );
1073 sub _release_space {
1075 my ($size, $loc) = @_;
1079 $self->_storage->print_at( $loc,
1081 pack($self->{long_pack}, $size ),
1082 pack($self->{long_pack}, $next_loc ),
1089 die "DBM::Deep: $_[1]\n";
1092 sub _get_dbm_object {
1096 local $SIG{__DIE__};
1097 if ($item->isa( 'DBM::Deep' )) {
1102 return $obj if $obj;
1104 my $r = Scalar::Util::reftype( $item ) || '';
1105 if ( $r eq 'HASH' ) {
1107 local $SIG{__DIE__};
1108 my $obj = tied(%$item);
1109 if ($obj->isa( 'DBM::Deep' )) {
1114 return $obj if $obj;
1116 elsif ( $r eq 'ARRAY' ) {
1118 local $SIG{__DIE__};
1119 my $obj = tied(@$item);
1120 if ($obj->isa( 'DBM::Deep' )) {
1125 return $obj if $obj;
1131 sub _length_needed {
1133 my ($value, $key) = @_;
1135 my $is_dbm_deep = eval {
1136 local $SIG{'__DIE__'};
1137 $value->isa( 'DBM::Deep' );
1141 + $self->{data_size} # size for value
1142 + $self->{data_size} # size for key
1143 + length( $key ); # length of key
1145 if ( $is_dbm_deep && $value->_storage eq $self->_storage ) {
1146 # long_size is for the internal reference
1147 return $len + $self->{long_size};
1150 if ( $self->_storage->{autobless} ) {
1151 # This is for the bit saying whether or not this thing is blessed.
1155 my $r = Scalar::Util::reftype( $value ) || '';
1156 unless ( $r eq 'HASH' || $r eq 'ARRAY' ) {
1157 if ( defined $value ) {
1158 $len += length( $value );
1163 $len += $self->{index_size};
1165 # if autobless is enabled, must also take into consideration
1166 # the class name as it is stored after the key.
1167 if ( $self->_storage->{autobless} ) {
1168 my $c = Scalar::Util::blessed($value);
1169 if ( defined $c && !$is_dbm_deep ) {
1170 $len += $self->{data_size} + length($c);