1 package DBM::Deep::Engine;
8 our $VERSION = q(0.99_03);
10 use Fcntl qw( :DEFAULT :flock );
14 # * To add to bucket_size, make sure you modify the following:
17 # - add_bucket() - where the buckets are printed
19 # * Every method in here assumes that the _fileobj has been appropriately
20 # safeguarded. This can be anything from flock() to some sort of manual
21 # mutex. But, it's the caller's responsability to make sure that this has
25 # Setup file and tag signatures. These should never change.
27 sub SIG_FILE () { 'DPDB' }
28 sub SIG_HEADER () { 'h' }
29 sub SIG_INTERNAL () { 'i' }
30 sub SIG_HASH () { 'H' }
31 sub SIG_ARRAY () { 'A' }
32 sub SIG_NULL () { 'N' }
33 sub SIG_DATA () { 'D' }
34 sub SIG_INDEX () { 'I' }
35 sub SIG_BLIST () { 'B' }
36 sub SIG_FREE () { 'F' }
37 sub SIG_KEYS () { 'K' }
40 ################################################################################
42 # This is new code. It is a complete rewrite of the engine based on a new API
44 ################################################################################
48 my ($offset, $key, $value, $orig_key) = @_;
50 my $dig_key = $self->apply_digest( $key );
51 my $tag = $self->find_blist( $offset, $dig_key, { create => 1 } );
52 return $self->add_bucket( $tag, $dig_key, $key, $value, undef, $orig_key );
57 my ($offset, $key, $orig_key) = @_;
59 my $dig_key = $self->apply_digest( $key );
60 my $tag = $self->find_blist( $offset, $dig_key ) or return;
61 return $self->get_bucket_value( $tag, $dig_key, $orig_key );
66 my ($offset, $key, $orig_key) = @_;
68 my $dig_key = $self->apply_digest( $key );
69 my $tag = $self->find_blist( $offset, $dig_key ) or return;
70 my $value = $self->get_bucket_value( $tag, $dig_key, $orig_key );
71 $self->delete_bucket( $tag, $dig_key, $orig_key );
77 my ($offset, $key) = @_;
79 my $dig_key = $self->apply_digest( $key );
80 # exists() returns the empty string, not undef
81 my $tag = $self->find_blist( $offset, $dig_key ) or return '';
82 return $self->bucket_exists( $tag, $dig_key, $key );
87 my ($offset, $prev_key) = @_;
89 # my $dig_key = $self->apply_digest( $key );
92 ################################################################################
94 # Below here is the old code. It will be folded into the code above as it can.
96 ################################################################################
108 digest => \&Digest::MD5::md5,
109 hash_size => 16, # In bytes
112 # Number of buckets per blist before another level of indexing is
113 # done. Increase this value for slightly greater speed, but larger database
114 # files. DO NOT decrease this value below 16, due to risk of recursive
123 if ( defined $args->{pack_size} ) {
124 if ( lc $args->{pack_size} eq 'small' ) {
125 $args->{long_size} = 2;
126 $args->{long_pack} = 'n';
128 elsif ( lc $args->{pack_size} eq 'medium' ) {
129 $args->{long_size} = 4;
130 $args->{long_pack} = 'N';
132 elsif ( lc $args->{pack_size} eq 'large' ) {
133 $args->{long_size} = 8;
134 $args->{long_pack} = 'Q';
137 die "Unknown pack_size value: '$args->{pack_size}'\n";
141 # Grab the parameters we want to use
142 foreach my $param ( keys %$self ) {
143 next unless exists $args->{$param};
144 $self->{$param} = $args->{$param};
146 Scalar::Util::weaken( $self->{obj} ) if $self->{obj};
148 if ( $self->{max_buckets} < 16 ) {
149 warn "Floor of max_buckets is 16. Setting it to 16 from '$self->{max_buckets}'\n";
150 $self->{max_buckets} = 16;
156 sub _fileobj { return $_[0]{fileobj} }
160 return $self->{digest}->(@_);
163 sub calculate_sizes {
166 # The 2**8 here indicates the number of different characters in the
167 # current hashing algorithm
168 #XXX Does this need to be updated with different hashing algorithms?
169 $self->{hash_chars_used} = (2**8);
170 $self->{index_size} = $self->{hash_chars_used} * $self->{long_size};
172 $self->{bucket_size} = $self->{hash_size} + $self->{long_size} * 2;
173 $self->{bucket_list_size} = $self->{max_buckets} * $self->{bucket_size};
175 $self->{key_size} = $self->{long_size} * 2;
176 $self->{keyloc_size} = $self->{max_buckets} * $self->{key_size};
181 sub write_file_header {
184 my $loc = $self->_fileobj->request_space( length( SIG_FILE ) + 33 );
186 $self->_fileobj->print_at( $loc,
189 pack('N', 1), # header version
190 pack('N', 24), # header size
191 pack('N4', 0, 0, 0, 0), # currently running transaction IDs
192 pack('n', $self->{long_size}),
193 pack('A', $self->{long_pack}),
194 pack('n', $self->{data_size}),
195 pack('A', $self->{data_pack}),
196 pack('n', $self->{max_buckets}),
199 $self->_fileobj->set_transaction_offset( 13 );
204 sub read_file_header {
207 my $buffer = $self->_fileobj->read_at( 0, length(SIG_FILE) + 9 );
208 return unless length($buffer);
210 my ($file_signature, $sig_header, $header_version, $size) = unpack(
214 unless ( $file_signature eq SIG_FILE ) {
215 $self->_fileobj->close;
216 $self->_throw_error( "Signature not found -- file is not a Deep DB" );
219 unless ( $sig_header eq SIG_HEADER ) {
220 $self->_fileobj->close;
221 $self->_throw_error( "Old file version found." );
224 my $buffer2 = $self->_fileobj->read_at( undef, $size );
225 my ($a1, $a2, $a3, $a4, @values) = unpack( 'N4 n A n A n', $buffer2 );
227 $self->_fileobj->set_transaction_offset( 13 );
229 if ( @values < 5 || grep { !defined } @values ) {
230 $self->_fileobj->close;
231 $self->_throw_error("Corrupted file - bad header");
234 #XXX Add warnings if values weren't set right
235 @{$self}{qw(long_size long_pack data_size data_pack max_buckets)} = @values;
237 return length($buffer) + length($buffer2);
244 # Need to remove use of $fh here
245 my $fh = $self->_fileobj->{fh};
248 #XXX The duplication of calculate_sizes needs to go away
249 unless ( $obj->{base_offset} ) {
250 my $bytes_read = $self->read_file_header;
252 $self->calculate_sizes;
255 # File is empty -- write header and master index
258 $self->_fileobj->audit( "# Database created on" );
260 $self->write_file_header;
262 $obj->{base_offset} = $self->_fileobj->request_space(
263 $self->tag_size( $self->{index_size} ),
267 $obj->_base_offset, $obj->_type,
268 chr(0)x$self->{index_size},
271 # Flush the filehandle
272 my $old_fh = select $fh;
273 my $old_af = $|; $| = 1; $| = $old_af;
277 $obj->{base_offset} = $bytes_read;
280 # Get our type from master index header
282 my $tag = $self->load_tag($obj->_base_offset);
285 $self->_throw_error("Corrupted file, no master index record");
288 unless ($obj->_type eq $tag->{signature}) {
290 $self->_throw_error("File type mismatch");
295 $self->calculate_sizes;
298 #XXX We have to make sure we don't mess up when autoflush isn't turned on
299 $self->_fileobj->set_inode;
309 return SIG_SIZE + $self->{data_size} + $size;
314 # Given offset, signature and content, create tag and write to disk
317 my ($offset, $sig, $content) = @_;
318 my $size = length( $content );
320 $self->_fileobj->print_at(
322 $sig, pack($self->{data_pack}, $size), $content,
325 return unless defined $offset;
329 #XXX Is this even used?
331 offset => $offset + SIG_SIZE + $self->{data_size},
338 # Given offset, load single tag and return signature, size and data
343 my $fileobj = $self->_fileobj;
345 my ($sig, $size) = unpack(
346 "A $self->{data_pack}",
347 $fileobj->read_at( $offset, SIG_SIZE + $self->{data_size} ),
352 size => $size, #XXX Is this even used?
353 offset => $offset + SIG_SIZE + $self->{data_size},
354 content => $fileobj->read_at( undef, $size ),
360 my ($tag, $transaction_id) = @_;
361 $transaction_id = $self->_fileobj->transaction_id
362 unless defined $transaction_id;
364 for ( my $i = 0; $i < $self->{max_buckets}; $i++ ) {
365 my ($loc, $trans_id, $is_deleted) = unpack(
366 "$self->{long_pack} C C",
367 substr( $tag->{content}, $i * $self->{key_size}, $self->{key_size} ),
371 return ( $loc, $is_deleted, $i * $self->{key_size} );
374 next if $transaction_id != $trans_id;
376 return ( $loc, $is_deleted, $i * $self->{key_size} );
384 # Adds one key/value pair to bucket list, given offset, MD5 digest of key,
385 # plain (undigested) key and value.
388 my ($tag, $md5, $plain_key, $value, $deleted, $orig_key) = @_;
390 # This verifies that only supported values will be stored.
392 my $r = Scalar::Util::reftype( $value );
395 last if $r eq 'HASH';
396 last if $r eq 'ARRAY';
399 "Storage of references of type '$r' is not supported."
403 my $fileobj = $self->_fileobj;
405 #ACID - This is a mutation. Must only find the exact transaction
406 my ($keyloc, $offset) = $self->_find_in_buckets( $tag, $md5, 1 );
409 if ( $fileobj->transaction_id == 0 ) {
410 @transactions = $fileobj->current_transactions;
413 # $self->_release_space( $size, $subloc );
414 #XXX This needs updating to use _release_space
417 my $size = $self->_length_needed( $value, $plain_key );
419 # Updating a known md5
421 my $keytag = $self->load_tag( $keyloc );
422 my ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
424 if ( $subloc && !$is_deleted && @transactions ) {
425 my $old_value = $self->read_from_loc( $subloc, $orig_key );
426 my $old_size = $self->_length_needed( $old_value, $plain_key );
428 for my $trans_id ( @transactions ) {
429 my ($loc, $is_deleted, $offset2) = $self->find_keyloc( $keytag, $trans_id );
431 my $location2 = $fileobj->request_space( $old_size );
432 $fileobj->print_at( $keytag->{offset} + $offset2,
433 pack($self->{long_pack}, $location2 ),
434 pack( 'C C', $trans_id, 0 ),
436 $self->_write_value( $location2, $plain_key, $old_value, $orig_key );
441 $location = $self->_fileobj->request_space( $size );
442 #XXX This needs to be transactionally-aware in terms of which keytag->{offset} to use
443 $fileobj->print_at( $keytag->{offset} + $offset,
444 pack($self->{long_pack}, $location ),
445 pack( 'C C', $fileobj->transaction_id, 0 ),
450 my $keyloc = $fileobj->request_space( $self->tag_size( $self->{keyloc_size} ) );
452 # The bucket fit into list
453 if ( defined $offset ) {
454 $fileobj->print_at( $tag->{offset} + $offset,
455 $md5, pack( $self->{long_pack}, $keyloc ),
458 # If bucket didn't fit into list, split into a new index level
460 $self->split_index( $tag, $md5, $keyloc );
463 my $keytag = $self->write_tag(
464 $keyloc, SIG_KEYS, chr(0)x$self->{keyloc_size},
467 $location = $self->_fileobj->request_space( $size );
468 $fileobj->print_at( $keytag->{offset},
469 pack( $self->{long_pack}, $location ),
470 pack( 'C C', $fileobj->transaction_id, 0 ),
474 for my $trans_id ( @transactions ) {
475 $fileobj->print_at( $keytag->{offset} + $self->{key_size} * $offset++,
476 pack( $self->{long_pack}, 0 ),
477 pack( 'C C', $trans_id, 1 ),
482 $self->_write_value( $location, $plain_key, $value, $orig_key );
489 my ($location, $key, $value, $orig_key) = @_;
491 my $fileobj = $self->_fileobj;
493 my $dbm_deep_obj = _get_dbm_object( $value );
494 if ( $dbm_deep_obj && $dbm_deep_obj->_fileobj ne $fileobj ) {
495 $self->_throw_error( "Cannot cross-reference. Use export() instead" );
499 # Write signature based on content type, set content length and write
502 my $r = Scalar::Util::reftype( $value ) || '';
503 if ( $dbm_deep_obj ) {
504 $self->write_tag( $location, SIG_INTERNAL,pack($self->{long_pack}, $dbm_deep_obj->_base_offset) );
506 elsif ($r eq 'HASH') {
507 if ( !$dbm_deep_obj && tied %{$value} ) {
508 $self->_throw_error( "Cannot store something that is tied" );
510 $self->write_tag( $location, SIG_HASH, chr(0)x$self->{index_size} );
512 elsif ($r eq 'ARRAY') {
513 if ( !$dbm_deep_obj && tied @{$value} ) {
514 $self->_throw_error( "Cannot store something that is tied" );
516 $self->write_tag( $location, SIG_ARRAY, chr(0)x$self->{index_size} );
518 elsif (!defined($value)) {
519 $self->write_tag( $location, SIG_NULL, '' );
522 $self->write_tag( $location, SIG_DATA, $value );
526 # Plain key is stored AFTER value, as keys are typically fetched less often.
528 $fileobj->print_at( undef, pack($self->{data_pack}, length($key)) . $key );
530 # Internal references don't care about autobless
531 return 1 if $dbm_deep_obj;
534 # If value is blessed, preserve class name
536 if ( $fileobj->{autobless} ) {
537 if ( defined( my $c = Scalar::Util::blessed($value) ) ) {
538 $fileobj->print_at( undef, chr(1), pack($self->{data_pack}, length($c)) . $c );
541 $fileobj->print_at( undef, chr(0) );
546 # Tie the passed in reference so that changes to it are reflected in the
547 # datafile. The use of $location as the base_offset will act as the
548 # the linkage between parent and child.
550 # The overall assignment is a hack around the fact that just tying doesn't
551 # store the values. This may not be the wrong thing to do.
555 tie %$value, 'DBM::Deep', {
556 base_offset => $location,
558 parent => $self->{obj},
559 parent_key => $orig_key,
563 elsif ($r eq 'ARRAY') {
565 tie @$value, 'DBM::Deep', {
566 base_offset => $location,
568 parent => $self->{obj},
569 parent_key => $orig_key,
579 my ($tag, $md5, $keyloc) = @_;
581 my $fileobj = $self->_fileobj;
583 my $loc = $fileobj->request_space(
584 $self->tag_size( $self->{index_size} ),
587 $fileobj->print_at( $tag->{ref_loc}, pack($self->{long_pack}, $loc) );
589 my $index_tag = $self->write_tag(
591 chr(0)x$self->{index_size},
594 my $keys = $tag->{content}
595 . $md5 . pack($self->{long_pack}, $keyloc);
599 # The <= here is deliberate - we have max_buckets+1 keys to iterate
600 # through, unlike every other loop that uses max_buckets as a stop.
601 for (my $i = 0; $i <= $self->{max_buckets}; $i++) {
602 my ($key, $old_subloc) = $self->_get_key_subloc( $keys, $i );
604 die "[INTERNAL ERROR]: No key in split_index()\n" unless $key;
605 die "[INTERNAL ERROR]: No subloc in split_index()\n" unless $old_subloc;
607 my $num = ord(substr($key, $tag->{ch} + 1, 1));
610 my $subkeys = $fileobj->read_at( $newloc[$num], $self->{bucket_list_size} );
612 # This is looking for the first empty spot
613 my ($subloc, $offset) = $self->_find_in_buckets(
614 { content => $subkeys }, '',
618 $newloc[$num] + $offset,
619 $key, pack($self->{long_pack}, $old_subloc),
625 my $loc = $fileobj->request_space(
626 $self->tag_size( $self->{bucket_list_size} ),
630 $index_tag->{offset} + ($num * $self->{long_size}),
631 pack($self->{long_pack}, $loc),
634 my $blist_tag = $self->write_tag(
636 chr(0)x$self->{bucket_list_size},
639 $fileobj->print_at( $blist_tag->{offset}, $key . pack($self->{long_pack}, $old_subloc) );
641 $newloc[$num] = $blist_tag->{offset};
644 $self->_release_space(
645 $self->tag_size( $self->{bucket_list_size} ),
646 $tag->{offset} - SIG_SIZE - $self->{data_size},
654 my ($subloc, $orig_key) = @_;
656 my $fileobj = $self->_fileobj;
658 my $signature = $fileobj->read_at( $subloc, SIG_SIZE );
661 # If value is a hash or array, return new DBM::Deep object with correct offset
663 if (($signature eq SIG_HASH) || ($signature eq SIG_ARRAY)) {
664 #XXX This needs to be a singleton
665 my $new_obj = DBM::Deep->new({
667 base_offset => $subloc,
668 fileobj => $self->_fileobj,
669 parent => $self->{obj},
670 parent_key => $orig_key,
673 if ($new_obj->_fileobj->{autobless}) {
675 # Skip over value and plain key to see if object needs
678 $fileobj->increment_pointer( $self->{data_size} + $self->{index_size} );
680 my $size = $fileobj->read_at( undef, $self->{data_size} );
681 $size = unpack($self->{data_pack}, $size);
682 if ($size) { $fileobj->increment_pointer( $size ); }
684 my $bless_bit = $fileobj->read_at( undef, 1 );
685 if ( ord($bless_bit) ) {
688 $fileobj->read_at( undef, $self->{data_size} ),
692 $new_obj = bless $new_obj, $fileobj->read_at( undef, $size );
699 elsif ( $signature eq SIG_INTERNAL ) {
700 my $size = $fileobj->read_at( undef, $self->{data_size} );
701 $size = unpack($self->{data_pack}, $size);
704 my $new_loc = $fileobj->read_at( undef, $size );
705 $new_loc = unpack( $self->{long_pack}, $new_loc );
706 return $self->read_from_loc( $new_loc, $orig_key );
713 # Otherwise return actual value
715 elsif ( $signature eq SIG_DATA ) {
716 my $size = $fileobj->read_at( undef, $self->{data_size} );
717 $size = unpack($self->{data_pack}, $size);
719 my $value = $size ? $fileobj->read_at( undef, $size ) : '';
724 # Key exists, but content is null
729 sub get_bucket_value {
731 # Fetch single value given tag and MD5 digested key.
734 my ($tag, $md5, $orig_key) = @_;
736 #ACID - This is a read. Can find exact or HEAD
737 my ($keyloc, $offset) = $self->_find_in_buckets( $tag, $md5 );
740 #XXX Need to use real key
741 # $self->add_bucket( $tag, $md5, $orig_key, undef, $orig_key );
744 # elsif ( !$is_deleted ) {
746 my $keytag = $self->load_tag( $keyloc );
747 my ($subloc, $is_deleted) = $self->find_keyloc( $keytag );
748 if (!$subloc && !$is_deleted) {
749 ($subloc, $is_deleted) = $self->find_keyloc( $keytag, 0 );
751 if ( $subloc && !$is_deleted ) {
752 return $self->read_from_loc( $subloc, $orig_key );
761 # Delete single key/value pair given tag and MD5 digested key.
764 my ($tag, $md5, $orig_key) = @_;
766 #ACID - Although this is a mutation, we must find any transaction.
767 # This is because we need to mark something as deleted that is in the HEAD.
768 my ($keyloc, $offset) = $self->_find_in_buckets( $tag, $md5 );
772 my $fileobj = $self->_fileobj;
775 if ( $fileobj->transaction_id == 0 ) {
776 @transactions = $fileobj->current_transactions;
779 if ( $fileobj->transaction_id == 0 ) {
780 my $keytag = $self->load_tag( $keyloc );
782 my ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
783 return if !$subloc || $is_deleted;
785 my $value = $self->read_from_loc( $subloc, $orig_key );
787 my $size = $self->_length_needed( $value, $orig_key );
789 for my $trans_id ( @transactions ) {
790 my ($loc, $is_deleted, $offset2) = $self->find_keyloc( $keytag, $trans_id );
792 my $location2 = $fileobj->request_space( $size );
793 $fileobj->print_at( $keytag->{offset} + $offset2,
794 pack($self->{long_pack}, $location2 ),
795 pack( 'C C', $trans_id, 0 ),
797 $self->_write_value( $location2, $orig_key, $value, $orig_key );
801 $keytag = $self->load_tag( $keyloc );
802 ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
803 $fileobj->print_at( $keytag->{offset} + $offset,
804 substr( $keytag->{content}, $offset + $self->{key_size} ),
805 chr(0) x $self->{key_size},
809 my $keytag = $self->load_tag( $keyloc );
811 my ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
813 $fileobj->print_at( $keytag->{offset} + $offset,
814 pack($self->{long_pack}, 0 ),
815 pack( 'C C', $fileobj->transaction_id, 1 ),
824 # Check existence of single key given tag and MD5 digested key.
827 my ($tag, $md5) = @_;
829 #ACID - This is a read. Can find exact or HEAD
830 my ($keyloc) = $self->_find_in_buckets( $tag, $md5 );
831 my $keytag = $self->load_tag( $keyloc );
832 my ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
833 if ( !$subloc && !$is_deleted ) {
834 ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag, 0 );
836 return ($subloc && !$is_deleted) && 1;
841 # Locate offset for bucket list, given digested key
844 my ($offset, $md5, $args) = @_;
845 $args = {} unless $args;
848 # Locate offset for bucket list using digest index system
850 my $tag = $self->load_tag( $offset )
851 or $self->_throw_error( "INTERNAL ERROR - Cannot find tag" );
854 while ($tag->{signature} ne SIG_BLIST) {
855 my $num = ord substr($md5, $ch, 1);
857 my $ref_loc = $tag->{offset} + ($num * $self->{long_size});
858 $tag = $self->index_lookup( $tag, $num );
861 return if !$args->{create};
863 my $loc = $self->_fileobj->request_space(
864 $self->tag_size( $self->{bucket_list_size} ),
867 $self->_fileobj->print_at( $ref_loc, pack($self->{long_pack}, $loc) );
869 $tag = $self->write_tag(
871 chr(0)x$self->{bucket_list_size},
874 $tag->{ref_loc} = $ref_loc;
881 $tag->{ref_loc} = $ref_loc;
889 # Given index tag, lookup single entry in index and return .
892 my ($tag, $index) = @_;
894 my $location = unpack(
898 $index * $self->{long_size},
903 if (!$location) { return; }
905 return $self->load_tag( $location );
910 # Scan index and recursively step into deeper levels, looking for next key.
913 my ($xxxx, $offset, $ch, $force_return_next) = @_;
915 my $tag = $self->load_tag( $offset );
917 if ($tag->{signature} ne SIG_BLIST) {
918 my $start = $xxxx->{return_next} ? 0 : ord(substr($xxxx->{prev_md5}, $ch, 1));
920 for (my $idx = $start; $idx < $self->{hash_chars_used}; $idx++) {
925 $idx * $self->{long_size},
931 my $result = $self->traverse_index(
932 $xxxx, $subloc, $ch + 1, $force_return_next,
935 if (defined $result) { return $result; }
939 $xxxx->{return_next} = 1;
941 # This is the bucket list
943 my $keys = $tag->{content};
944 if ($force_return_next) { $xxxx->{return_next} = 1; }
947 # Iterate through buckets, looking for a key match
949 my $transaction_id = $self->_fileobj->transaction_id;
950 for (my $i = 0; $i < $self->{max_buckets}; $i++) {
951 my ($key, $keyloc) = $self->_get_key_subloc( $keys, $i );
953 # End of bucket list -- return to outer loop
955 $xxxx->{return_next} = 1;
958 # Located previous key -- return next one found
959 elsif ($key eq $xxxx->{prev_md5}) {
960 $xxxx->{return_next} = 1;
963 # Seek to bucket location and skip over signature
964 elsif ($xxxx->{return_next}) {
965 my $fileobj = $self->_fileobj;
967 my $keytag = $self->load_tag( $keyloc );
968 my ($subloc, $is_deleted) = $self->find_keyloc( $keytag );
969 if ( $subloc == 0 && !$is_deleted ) {
970 ($subloc, $is_deleted) = $self->find_keyloc( $keytag, 0 );
974 # Skip over value to get to plain key
975 my $sig = $fileobj->read_at( $subloc, SIG_SIZE );
977 my $size = $fileobj->read_at( undef, $self->{data_size} );
978 $size = unpack($self->{data_pack}, $size);
979 if ($size) { $fileobj->increment_pointer( $size ); }
981 # Read in plain key and return as scalar
982 $size = $fileobj->read_at( undef, $self->{data_size} );
983 $size = unpack($self->{data_pack}, $size);
986 if ($size) { $plain_key = $fileobj->read_at( undef, $size); }
991 $xxxx->{return_next} = 1;
999 # Locate next key, given digested previous one
1005 # If the previous key was not specifed, start at the top and
1006 # return the first one found.
1017 prev_md5 => chr(0) x $self->{hash_size},
1022 return $self->traverse_index( $temp, $obj->_base_offset, 0 );
1027 sub _get_key_subloc {
1029 my ($keys, $idx) = @_;
1032 # This is 'a', not 'A'. Please read the pack() documentation for the
1033 # difference between the two and why it's important.
1034 "a$self->{hash_size} $self->{long_pack}",
1037 ($idx * $self->{bucket_size}),
1038 $self->{bucket_size},
1043 sub _find_in_buckets {
1045 my ($tag, $md5) = @_;
1048 for ( my $i = 0; $i < $self->{max_buckets}; $i++ ) {
1049 my ($key, $subloc) = $self->_get_key_subloc(
1050 $tag->{content}, $i,
1053 my @rv = ($subloc, $i * $self->{bucket_size});
1055 unless ( $subloc ) {
1059 next BUCKET if $key ne $md5;
1067 sub _release_space {
1069 my ($size, $loc) = @_;
1073 $self->_fileobj->print_at( $loc,
1075 pack($self->{long_pack}, $size ),
1076 pack($self->{long_pack}, $next_loc ),
1083 die "DBM::Deep: $_[1]\n";
1086 sub _get_dbm_object {
1090 local $SIG{__DIE__};
1091 if ($item->isa( 'DBM::Deep' )) {
1096 return $obj if $obj;
1098 my $r = Scalar::Util::reftype( $item ) || '';
1099 if ( $r eq 'HASH' ) {
1101 local $SIG{__DIE__};
1102 my $obj = tied(%$item);
1103 if ($obj->isa( 'DBM::Deep' )) {
1108 return $obj if $obj;
1110 elsif ( $r eq 'ARRAY' ) {
1112 local $SIG{__DIE__};
1113 my $obj = tied(@$item);
1114 if ($obj->isa( 'DBM::Deep' )) {
1119 return $obj if $obj;
1125 sub _length_needed {
1127 my ($value, $key) = @_;
1129 my $is_dbm_deep = eval {
1130 local $SIG{'__DIE__'};
1131 $value->isa( 'DBM::Deep' );
1135 + $self->{data_size} # size for value
1136 + $self->{data_size} # size for key
1137 + length( $key ); # length of key
1139 if ( $is_dbm_deep && $value->_fileobj eq $self->_fileobj ) {
1140 # long_size is for the internal reference
1141 return $len + $self->{long_size};
1144 if ( $self->_fileobj->{autobless} ) {
1145 # This is for the bit saying whether or not this thing is blessed.
1149 my $r = Scalar::Util::reftype( $value ) || '';
1150 unless ( $r eq 'HASH' || $r eq 'ARRAY' ) {
1151 if ( defined $value ) {
1152 $len += length( $value );
1157 $len += $self->{index_size};
1159 # if autobless is enabled, must also take into consideration
1160 # the class name as it is stored after the key.
1161 if ( $self->_fileobj->{autobless} ) {
1162 my $c = Scalar::Util::blessed($value);
1163 if ( defined $c && !$is_dbm_deep ) {
1164 $len += $self->{data_size} + length($c);