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) = @_;
59 my $dig_key = $self->apply_digest( $key );
60 my $tag = $self->find_blist( $offset, $dig_key );
61 return $self->get_bucket_value( $tag, $dig_key, $key );
66 my ($offset, $key) = @_;
68 my $dig_key = $self->apply_digest( $key );
69 my $tag = $self->find_blist( $offset, $dig_key );
70 return $self->delete_bucket( $tag, $dig_key, $key );
75 my ($offset, $key) = @_;
77 my $dig_key = $self->apply_digest( $key );
78 my $tag = $self->find_blist( $offset, $dig_key );
79 return $self->bucket_exists( $tag, $dig_key, $key );
84 my ($offset, $prev_key) = @_;
86 # my $dig_key = $self->apply_digest( $key );
89 ################################################################################
91 # Below here is the old code. It will be folded into the code above as it can.
93 ################################################################################
105 digest => \&Digest::MD5::md5,
106 hash_size => 16, # In bytes
109 # Number of buckets per blist before another level of indexing is
110 # done. Increase this value for slightly greater speed, but larger database
111 # files. DO NOT decrease this value below 16, due to risk of recursive
120 if ( defined $args->{pack_size} ) {
121 if ( lc $args->{pack_size} eq 'small' ) {
122 $args->{long_size} = 2;
123 $args->{long_pack} = 'n';
125 elsif ( lc $args->{pack_size} eq 'medium' ) {
126 $args->{long_size} = 4;
127 $args->{long_pack} = 'N';
129 elsif ( lc $args->{pack_size} eq 'large' ) {
130 $args->{long_size} = 8;
131 $args->{long_pack} = 'Q';
134 die "Unknown pack_size value: '$args->{pack_size}'\n";
138 # Grab the parameters we want to use
139 foreach my $param ( keys %$self ) {
140 next unless exists $args->{$param};
141 $self->{$param} = $args->{$param};
143 Scalar::Util::weaken( $self->{obj} ) if $self->{obj};
145 if ( $self->{max_buckets} < 16 ) {
146 warn "Floor of max_buckets is 16. Setting it to 16 from '$self->{max_buckets}'\n";
147 $self->{max_buckets} = 16;
153 sub _fileobj { return $_[0]{fileobj} }
157 return $self->{digest}->(@_);
160 sub calculate_sizes {
163 # The 2**8 here indicates the number of different characters in the
164 # current hashing algorithm
165 #XXX Does this need to be updated with different hashing algorithms?
166 $self->{hash_chars_used} = (2**8);
167 $self->{index_size} = $self->{hash_chars_used} * $self->{long_size};
169 $self->{bucket_size} = $self->{hash_size} + $self->{long_size} * 2;
170 $self->{bucket_list_size} = $self->{max_buckets} * $self->{bucket_size};
172 $self->{key_size} = $self->{long_size} * 2;
173 $self->{keyloc_size} = $self->{max_buckets} * $self->{key_size};
178 sub write_file_header {
181 my $loc = $self->_fileobj->request_space( length( SIG_FILE ) + 33 );
183 $self->_fileobj->print_at( $loc,
186 pack('N', 1), # header version
187 pack('N', 24), # header size
188 pack('N4', 0, 0, 0, 0), # currently running transaction IDs
189 pack('n', $self->{long_size}),
190 pack('A', $self->{long_pack}),
191 pack('n', $self->{data_size}),
192 pack('A', $self->{data_pack}),
193 pack('n', $self->{max_buckets}),
196 $self->_fileobj->set_transaction_offset( 13 );
201 sub read_file_header {
204 my $buffer = $self->_fileobj->read_at( 0, length(SIG_FILE) + 9 );
205 return unless length($buffer);
207 my ($file_signature, $sig_header, $header_version, $size) = unpack(
211 unless ( $file_signature eq SIG_FILE ) {
212 $self->_fileobj->close;
213 $self->_throw_error( "Signature not found -- file is not a Deep DB" );
216 unless ( $sig_header eq SIG_HEADER ) {
217 $self->_fileobj->close;
218 $self->_throw_error( "Old file version found." );
221 my $buffer2 = $self->_fileobj->read_at( undef, $size );
222 my ($a1, $a2, $a3, $a4, @values) = unpack( 'N4 n A n A n', $buffer2 );
224 $self->_fileobj->set_transaction_offset( 13 );
226 if ( @values < 5 || grep { !defined } @values ) {
227 $self->_fileobj->close;
228 $self->_throw_error("Corrupted file - bad header");
231 #XXX Add warnings if values weren't set right
232 @{$self}{qw(long_size long_pack data_size data_pack max_buckets)} = @values;
234 return length($buffer) + length($buffer2);
241 # Need to remove use of $fh here
242 my $fh = $self->_fileobj->{fh};
245 #XXX The duplication of calculate_sizes needs to go away
246 unless ( $obj->{base_offset} ) {
247 my $bytes_read = $self->read_file_header;
249 $self->calculate_sizes;
252 # File is empty -- write header and master index
255 $self->_fileobj->audit( "# Database created on" );
257 $self->write_file_header;
259 $obj->{base_offset} = $self->_fileobj->request_space(
260 $self->tag_size( $self->{index_size} ),
264 $obj->_base_offset, $obj->_type,
265 chr(0)x$self->{index_size},
268 # Flush the filehandle
269 my $old_fh = select $fh;
270 my $old_af = $|; $| = 1; $| = $old_af;
274 $obj->{base_offset} = $bytes_read;
277 # Get our type from master index header
279 my $tag = $self->load_tag($obj->_base_offset);
282 $self->_throw_error("Corrupted file, no master index record");
285 unless ($obj->_type eq $tag->{signature}) {
287 $self->_throw_error("File type mismatch");
292 $self->calculate_sizes;
295 #XXX We have to make sure we don't mess up when autoflush isn't turned on
296 $self->_fileobj->set_inode;
306 return SIG_SIZE + $self->{data_size} + $size;
311 # Given offset, signature and content, create tag and write to disk
314 my ($offset, $sig, $content) = @_;
315 my $size = length( $content );
317 $self->_fileobj->print_at(
319 $sig, pack($self->{data_pack}, $size), $content,
322 return unless defined $offset;
326 #XXX Is this even used?
328 offset => $offset + SIG_SIZE + $self->{data_size},
335 # Given offset, load single tag and return signature, size and data
340 my $fileobj = $self->_fileobj;
342 my ($sig, $size) = unpack(
343 "A $self->{data_pack}",
344 $fileobj->read_at( $offset, SIG_SIZE + $self->{data_size} ),
349 size => $size, #XXX Is this even used?
350 offset => $offset + SIG_SIZE + $self->{data_size},
351 content => $fileobj->read_at( undef, $size ),
357 my ($tag, $transaction_id) = @_;
358 $transaction_id = $self->_fileobj->transaction_id
359 unless defined $transaction_id;
361 for ( my $i = 0; $i < $self->{max_buckets}; $i++ ) {
362 my ($loc, $trans_id, $is_deleted) = unpack(
363 "$self->{long_pack} C C",
364 substr( $tag->{content}, $i * $self->{key_size}, $self->{key_size} ),
368 return ( $loc, $is_deleted, $i * $self->{key_size} );
371 next if $transaction_id != $trans_id;
373 return ( $loc, $is_deleted, $i * $self->{key_size} );
381 # Adds one key/value pair to bucket list, given offset, MD5 digest of key,
382 # plain (undigested) key and value.
385 my ($tag, $md5, $plain_key, $value, $deleted, $orig_key) = @_;
387 # This verifies that only supported values will be stored.
389 my $r = Scalar::Util::reftype( $value );
392 last if $r eq 'HASH';
393 last if $r eq 'ARRAY';
396 "Storage of references of type '$r' is not supported."
400 my $fileobj = $self->_fileobj;
402 #ACID - This is a mutation. Must only find the exact transaction
403 my ($keyloc, $offset) = $self->_find_in_buckets( $tag, $md5, 1 );
406 if ( $fileobj->transaction_id == 0 ) {
407 @transactions = $fileobj->current_transactions;
410 # $self->_release_space( $size, $subloc );
411 #XXX This needs updating to use _release_space
414 my $size = $self->_length_needed( $value, $plain_key );
416 # Updating a known md5
418 my $keytag = $self->load_tag( $keyloc );
419 my ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
421 if ( $subloc && !$is_deleted && @transactions ) {
422 my $old_value = $self->read_from_loc( $subloc, $orig_key );
423 my $old_size = $self->_length_needed( $old_value, $plain_key );
425 for my $trans_id ( @transactions ) {
426 my ($loc, $is_deleted, $offset2) = $self->find_keyloc( $keytag, $trans_id );
428 my $location2 = $fileobj->request_space( $old_size );
429 $fileobj->print_at( $keytag->{offset} + $offset2,
430 pack($self->{long_pack}, $location2 ),
431 pack( 'C C', $trans_id, 0 ),
433 $self->_write_value( $location2, $plain_key, $old_value, $orig_key );
438 $location = $self->_fileobj->request_space( $size );
439 #XXX This needs to be transactionally-aware in terms of which keytag->{offset} to use
440 $fileobj->print_at( $keytag->{offset} + $offset,
441 pack($self->{long_pack}, $location ),
442 pack( 'C C', $fileobj->transaction_id, 0 ),
447 my $keyloc = $fileobj->request_space( $self->tag_size( $self->{keyloc_size} ) );
449 # The bucket fit into list
450 if ( defined $offset ) {
451 $fileobj->print_at( $tag->{offset} + $offset,
452 $md5, pack( $self->{long_pack}, $keyloc ),
455 # If bucket didn't fit into list, split into a new index level
457 $self->split_index( $tag, $md5, $keyloc );
460 my $keytag = $self->write_tag(
461 $keyloc, SIG_KEYS, chr(0)x$self->{keyloc_size},
464 $location = $self->_fileobj->request_space( $size );
465 $fileobj->print_at( $keytag->{offset},
466 pack( $self->{long_pack}, $location ),
467 pack( 'C C', $fileobj->transaction_id, 0 ),
471 for my $trans_id ( @transactions ) {
472 $fileobj->print_at( $keytag->{offset} + $self->{key_size} * $offset++,
473 pack( $self->{long_pack}, 0 ),
474 pack( 'C C', $trans_id, 1 ),
479 $self->_write_value( $location, $plain_key, $value, $orig_key );
486 my ($location, $key, $value, $orig_key) = @_;
488 my $fileobj = $self->_fileobj;
490 my $dbm_deep_obj = _get_dbm_object( $value );
491 if ( $dbm_deep_obj && $dbm_deep_obj->_fileobj ne $fileobj ) {
492 $self->_throw_error( "Cannot cross-reference. Use export() instead" );
496 # Write signature based on content type, set content length and write
499 my $r = Scalar::Util::reftype( $value ) || '';
500 if ( $dbm_deep_obj ) {
501 $self->write_tag( $location, SIG_INTERNAL,pack($self->{long_pack}, $dbm_deep_obj->_base_offset) );
503 elsif ($r eq 'HASH') {
504 if ( !$dbm_deep_obj && tied %{$value} ) {
505 $self->_throw_error( "Cannot store something that is tied" );
507 $self->write_tag( $location, SIG_HASH, chr(0)x$self->{index_size} );
509 elsif ($r eq 'ARRAY') {
510 if ( !$dbm_deep_obj && tied @{$value} ) {
511 $self->_throw_error( "Cannot store something that is tied" );
513 $self->write_tag( $location, SIG_ARRAY, chr(0)x$self->{index_size} );
515 elsif (!defined($value)) {
516 $self->write_tag( $location, SIG_NULL, '' );
519 $self->write_tag( $location, SIG_DATA, $value );
523 # Plain key is stored AFTER value, as keys are typically fetched less often.
525 $fileobj->print_at( undef, pack($self->{data_pack}, length($key)) . $key );
527 # Internal references don't care about autobless
528 return 1 if $dbm_deep_obj;
531 # If value is blessed, preserve class name
533 if ( $fileobj->{autobless} ) {
534 if ( defined( my $c = Scalar::Util::blessed($value) ) ) {
535 $fileobj->print_at( undef, chr(1), pack($self->{data_pack}, length($c)) . $c );
538 $fileobj->print_at( undef, chr(0) );
543 # Tie the passed in reference so that changes to it are reflected in the
544 # datafile. The use of $location as the base_offset will act as the
545 # the linkage between parent and child.
547 # The overall assignment is a hack around the fact that just tying doesn't
548 # store the values. This may not be the wrong thing to do.
552 tie %$value, 'DBM::Deep', {
553 base_offset => $location,
555 parent => $self->{obj},
556 parent_key => $orig_key,
560 elsif ($r eq 'ARRAY') {
562 tie @$value, 'DBM::Deep', {
563 base_offset => $location,
565 parent => $self->{obj},
566 parent_key => $orig_key,
576 my ($tag, $md5, $keyloc) = @_;
578 my $fileobj = $self->_fileobj;
580 my $loc = $fileobj->request_space(
581 $self->tag_size( $self->{index_size} ),
584 $fileobj->print_at( $tag->{ref_loc}, pack($self->{long_pack}, $loc) );
586 my $index_tag = $self->write_tag(
588 chr(0)x$self->{index_size},
591 my $keys = $tag->{content}
592 . $md5 . pack($self->{long_pack}, $keyloc);
596 # The <= here is deliberate - we have max_buckets+1 keys to iterate
597 # through, unlike every other loop that uses max_buckets as a stop.
598 for (my $i = 0; $i <= $self->{max_buckets}; $i++) {
599 my ($key, $old_subloc) = $self->_get_key_subloc( $keys, $i );
601 die "[INTERNAL ERROR]: No key in split_index()\n" unless $key;
602 die "[INTERNAL ERROR]: No subloc in split_index()\n" unless $old_subloc;
604 my $num = ord(substr($key, $tag->{ch} + 1, 1));
607 my $subkeys = $fileobj->read_at( $newloc[$num], $self->{bucket_list_size} );
609 # This is looking for the first empty spot
610 my ($subloc, $offset) = $self->_find_in_buckets(
611 { content => $subkeys }, '',
615 $newloc[$num] + $offset,
616 $key, pack($self->{long_pack}, $old_subloc),
622 my $loc = $fileobj->request_space(
623 $self->tag_size( $self->{bucket_list_size} ),
627 $index_tag->{offset} + ($num * $self->{long_size}),
628 pack($self->{long_pack}, $loc),
631 my $blist_tag = $self->write_tag(
633 chr(0)x$self->{bucket_list_size},
636 $fileobj->print_at( $blist_tag->{offset}, $key . pack($self->{long_pack}, $old_subloc) );
638 $newloc[$num] = $blist_tag->{offset};
641 $self->_release_space(
642 $self->tag_size( $self->{bucket_list_size} ),
643 $tag->{offset} - SIG_SIZE - $self->{data_size},
651 my ($subloc, $orig_key) = @_;
653 my $fileobj = $self->_fileobj;
655 my $signature = $fileobj->read_at( $subloc, SIG_SIZE );
658 # If value is a hash or array, return new DBM::Deep object with correct offset
660 if (($signature eq SIG_HASH) || ($signature eq SIG_ARRAY)) {
661 #XXX This needs to be a singleton
662 my $new_obj = DBM::Deep->new({
664 base_offset => $subloc,
665 fileobj => $self->_fileobj,
666 parent => $self->{obj},
667 parent_key => $orig_key,
670 if ($new_obj->_fileobj->{autobless}) {
672 # Skip over value and plain key to see if object needs
675 $fileobj->increment_pointer( $self->{data_size} + $self->{index_size} );
677 my $size = $fileobj->read_at( undef, $self->{data_size} );
678 $size = unpack($self->{data_pack}, $size);
679 if ($size) { $fileobj->increment_pointer( $size ); }
681 my $bless_bit = $fileobj->read_at( undef, 1 );
682 if ( ord($bless_bit) ) {
685 $fileobj->read_at( undef, $self->{data_size} ),
689 $new_obj = bless $new_obj, $fileobj->read_at( undef, $size );
696 elsif ( $signature eq SIG_INTERNAL ) {
697 my $size = $fileobj->read_at( undef, $self->{data_size} );
698 $size = unpack($self->{data_pack}, $size);
701 my $new_loc = $fileobj->read_at( undef, $size );
702 $new_loc = unpack( $self->{long_pack}, $new_loc );
703 return $self->read_from_loc( $new_loc, $orig_key );
710 # Otherwise return actual value
712 elsif ( $signature eq SIG_DATA ) {
713 my $size = $fileobj->read_at( undef, $self->{data_size} );
714 $size = unpack($self->{data_pack}, $size);
716 my $value = $size ? $fileobj->read_at( undef, $size ) : '';
721 # Key exists, but content is null
726 sub get_bucket_value {
728 # Fetch single value given tag and MD5 digested key.
731 my ($tag, $md5, $orig_key) = @_;
733 #ACID - This is a read. Can find exact or HEAD
734 my ($keyloc, $offset) = $self->_find_in_buckets( $tag, $md5 );
737 #XXX Need to use real key
738 # $self->add_bucket( $tag, $md5, $orig_key, undef, $orig_key );
741 # elsif ( !$is_deleted ) {
743 my $keytag = $self->load_tag( $keyloc );
744 my ($subloc, $is_deleted) = $self->find_keyloc( $keytag );
745 if (!$subloc && !$is_deleted) {
746 ($subloc, $is_deleted) = $self->find_keyloc( $keytag, 0 );
748 if ( $subloc && !$is_deleted ) {
749 return $self->read_from_loc( $subloc, $orig_key );
758 # Delete single key/value pair given tag and MD5 digested key.
761 my ($tag, $md5, $orig_key) = @_;
763 #ACID - Although this is a mutation, we must find any transaction.
764 # This is because we need to mark something as deleted that is in the HEAD.
765 my ($keyloc, $offset) = $self->_find_in_buckets( $tag, $md5 );
769 my $fileobj = $self->_fileobj;
772 if ( $fileobj->transaction_id == 0 ) {
773 @transactions = $fileobj->current_transactions;
776 if ( $fileobj->transaction_id == 0 ) {
777 my $keytag = $self->load_tag( $keyloc );
779 my ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
780 return if !$subloc || $is_deleted;
782 my $value = $self->read_from_loc( $subloc, $orig_key );
784 my $size = $self->_length_needed( $value, $orig_key );
786 for my $trans_id ( @transactions ) {
787 my ($loc, $is_deleted, $offset2) = $self->find_keyloc( $keytag, $trans_id );
789 my $location2 = $fileobj->request_space( $size );
790 $fileobj->print_at( $keytag->{offset} + $offset2,
791 pack($self->{long_pack}, $location2 ),
792 pack( 'C C', $trans_id, 0 ),
794 $self->_write_value( $location2, $orig_key, $value, $orig_key );
798 $keytag = $self->load_tag( $keyloc );
799 ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
800 $fileobj->print_at( $keytag->{offset} + $offset,
801 substr( $keytag->{content}, $offset + $self->{key_size} ),
802 chr(0) x $self->{key_size},
806 my $keytag = $self->load_tag( $keyloc );
808 my ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
810 $fileobj->print_at( $keytag->{offset} + $offset,
811 pack($self->{long_pack}, 0 ),
812 pack( 'C C', $fileobj->transaction_id, 1 ),
821 # Check existence of single key given tag and MD5 digested key.
824 my ($tag, $md5) = @_;
826 #ACID - This is a read. Can find exact or HEAD
827 my ($keyloc) = $self->_find_in_buckets( $tag, $md5 );
828 my $keytag = $self->load_tag( $keyloc );
829 my ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag );
830 if ( !$subloc && !$is_deleted ) {
831 ($subloc, $is_deleted, $offset) = $self->find_keyloc( $keytag, 0 );
833 return ($subloc && !$is_deleted) && 1;
838 # Locate offset for bucket list, given digested key
841 my ($offset, $md5, $args) = @_;
842 $args = {} unless $args;
845 # Locate offset for bucket list using digest index system
847 my $tag = $self->load_tag( $offset )
848 or $self->_throw_error( "INTERNAL ERROR - Cannot find tag" );
851 while ($tag->{signature} ne SIG_BLIST) {
852 my $num = ord substr($md5, $ch, 1);
854 my $ref_loc = $tag->{offset} + ($num * $self->{long_size});
855 $tag = $self->index_lookup( $tag, $num );
858 return if !$args->{create};
860 my $loc = $self->_fileobj->request_space(
861 $self->tag_size( $self->{bucket_list_size} ),
864 $self->_fileobj->print_at( $ref_loc, pack($self->{long_pack}, $loc) );
866 $tag = $self->write_tag(
868 chr(0)x$self->{bucket_list_size},
871 $tag->{ref_loc} = $ref_loc;
878 $tag->{ref_loc} = $ref_loc;
886 # Given index tag, lookup single entry in index and return .
889 my ($tag, $index) = @_;
891 my $location = unpack(
895 $index * $self->{long_size},
900 if (!$location) { return; }
902 return $self->load_tag( $location );
907 # Scan index and recursively step into deeper levels, looking for next key.
910 my ($xxxx, $offset, $ch, $force_return_next) = @_;
912 my $tag = $self->load_tag( $offset );
914 if ($tag->{signature} ne SIG_BLIST) {
915 my $start = $xxxx->{return_next} ? 0 : ord(substr($xxxx->{prev_md5}, $ch, 1));
917 for (my $idx = $start; $idx < $self->{hash_chars_used}; $idx++) {
922 $idx * $self->{long_size},
928 my $result = $self->traverse_index(
929 $xxxx, $subloc, $ch + 1, $force_return_next,
932 if (defined $result) { return $result; }
936 $xxxx->{return_next} = 1;
938 # This is the bucket list
940 my $keys = $tag->{content};
941 if ($force_return_next) { $xxxx->{return_next} = 1; }
944 # Iterate through buckets, looking for a key match
946 my $transaction_id = $self->_fileobj->transaction_id;
947 for (my $i = 0; $i < $self->{max_buckets}; $i++) {
948 my ($key, $keyloc) = $self->_get_key_subloc( $keys, $i );
950 # End of bucket list -- return to outer loop
952 $xxxx->{return_next} = 1;
955 # Located previous key -- return next one found
956 elsif ($key eq $xxxx->{prev_md5}) {
957 $xxxx->{return_next} = 1;
960 # Seek to bucket location and skip over signature
961 elsif ($xxxx->{return_next}) {
962 my $fileobj = $self->_fileobj;
964 my $keytag = $self->load_tag( $keyloc );
965 my ($subloc, $is_deleted) = $self->find_keyloc( $keytag );
966 if ( $subloc == 0 && !$is_deleted ) {
967 ($subloc, $is_deleted) = $self->find_keyloc( $keytag, 0 );
971 # Skip over value to get to plain key
972 my $sig = $fileobj->read_at( $subloc, SIG_SIZE );
974 my $size = $fileobj->read_at( undef, $self->{data_size} );
975 $size = unpack($self->{data_pack}, $size);
976 if ($size) { $fileobj->increment_pointer( $size ); }
978 # Read in plain key and return as scalar
979 $size = $fileobj->read_at( undef, $self->{data_size} );
980 $size = unpack($self->{data_pack}, $size);
983 if ($size) { $plain_key = $fileobj->read_at( undef, $size); }
988 $xxxx->{return_next} = 1;
996 # Locate next key, given digested previous one
1002 # If the previous key was not specifed, start at the top and
1003 # return the first one found.
1014 prev_md5 => chr(0) x $self->{hash_size},
1019 return $self->traverse_index( $temp, $obj->_base_offset, 0 );
1024 sub _get_key_subloc {
1026 my ($keys, $idx) = @_;
1029 # This is 'a', not 'A'. Please read the pack() documentation for the
1030 # difference between the two and why it's important.
1031 "a$self->{hash_size} $self->{long_pack}",
1034 ($idx * $self->{bucket_size}),
1035 $self->{bucket_size},
1040 sub _find_in_buckets {
1042 my ($tag, $md5) = @_;
1045 for ( my $i = 0; $i < $self->{max_buckets}; $i++ ) {
1046 my ($key, $subloc) = $self->_get_key_subloc(
1047 $tag->{content}, $i,
1050 my @rv = ($subloc, $i * $self->{bucket_size});
1052 unless ( $subloc ) {
1056 next BUCKET if $key ne $md5;
1064 sub _release_space {
1066 my ($size, $loc) = @_;
1070 $self->_fileobj->print_at( $loc,
1072 pack($self->{long_pack}, $size ),
1073 pack($self->{long_pack}, $next_loc ),
1080 die "DBM::Deep: $_[1]\n";
1083 sub _get_dbm_object {
1087 local $SIG{__DIE__};
1088 if ($item->isa( 'DBM::Deep' )) {
1093 return $obj if $obj;
1095 my $r = Scalar::Util::reftype( $item ) || '';
1096 if ( $r eq 'HASH' ) {
1098 local $SIG{__DIE__};
1099 my $obj = tied(%$item);
1100 if ($obj->isa( 'DBM::Deep' )) {
1105 return $obj if $obj;
1107 elsif ( $r eq 'ARRAY' ) {
1109 local $SIG{__DIE__};
1110 my $obj = tied(@$item);
1111 if ($obj->isa( 'DBM::Deep' )) {
1116 return $obj if $obj;
1122 sub _length_needed {
1124 my ($value, $key) = @_;
1126 my $is_dbm_deep = eval {
1127 local $SIG{'__DIE__'};
1128 $value->isa( 'DBM::Deep' );
1132 + $self->{data_size} # size for value
1133 + $self->{data_size} # size for key
1134 + length( $key ); # length of key
1136 if ( $is_dbm_deep && $value->_fileobj eq $self->_fileobj ) {
1137 # long_size is for the internal reference
1138 return $len + $self->{long_size};
1141 if ( $self->_fileobj->{autobless} ) {
1142 # This is for the bit saying whether or not this thing is blessed.
1146 my $r = Scalar::Util::reftype( $value ) || '';
1147 unless ( $r eq 'HASH' || $r eq 'ARRAY' ) {
1148 if ( defined $value ) {
1149 $len += length( $value );
1154 $len += $self->{index_size};
1156 # if autobless is enabled, must also take into consideration
1157 # the class name as it is stored after the key.
1158 if ( $self->_fileobj->{autobless} ) {
1159 my $c = Scalar::Util::blessed($value);
1160 if ( defined $c && !$is_dbm_deep ) {
1161 $len += $self->{data_size} + length($c);