1 package DBM::Deep::Engine3;
7 our $VERSION = q(0.99_03);
12 # * Every method in here assumes that the storage has been appropriately
13 # safeguarded. This can be anything from flock() to some sort of manual
14 # mutex. But, it's the caller's responsability to make sure that this has
17 # Setup file and tag signatures. These should never change.
18 sub SIG_FILE () { 'DPDB' }
19 sub SIG_HEADER () { 'h' }
20 sub SIG_INTERNAL () { 'i' }
21 sub SIG_HASH () { 'H' }
22 sub SIG_ARRAY () { 'A' }
23 sub SIG_NULL () { 'N' }
24 sub SIG_DATA () { 'D' }
25 sub SIG_INDEX () { 'I' }
26 sub SIG_BLIST () { 'B' }
27 sub SIG_FREE () { 'F' }
28 sub SIG_KEYS () { 'K' }
31 ################################################################################
33 # Please refer to the pack() documentation for further information
35 1 => 'C', # Unsigned char value
36 2 => 'n', # Unsigned short in "network" (big-endian) order
37 4 => 'N', # Unsigned long in "network" (big-endian) order
38 8 => 'Q', # Usigned quad (no order specified, presumably machine-dependent)
45 print "\n********* NEW ********\n\n";
50 hash_size => 16, # In bytes
52 num_txns => 16, # HEAD plus 15 running txns
53 trans_id => 0, # Default to the HEAD
55 entries => {}, # This is the list of entries for transactions
59 if ( defined $args->{pack_size} ) {
60 if ( lc $args->{pack_size} eq 'small' ) {
61 $args->{byte_size} = 2;
63 elsif ( lc $args->{pack_size} eq 'medium' ) {
64 $args->{byte_size} = 4;
66 elsif ( lc $args->{pack_size} eq 'large' ) {
67 $args->{byte_size} = 8;
70 die "Unknown pack_size value: '$args->{pack_size}'\n";
74 # Grab the parameters we want to use
75 foreach my $param ( keys %$self ) {
76 next unless exists $args->{$param};
77 $self->{$param} = $args->{$param};
80 $self->{byte_pack} = $StP{ $self->byte_size };
83 # Number of buckets per blist before another level of indexing is
84 # done. Increase this value for slightly greater speed, but larger database
85 # files. DO NOT decrease this value below 16, due to risk of recursive
88 if ( $self->{max_buckets} < 16 ) {
89 warn "Floor of max_buckets is 16. Setting it to 16 from '$self->{max_buckets}'\n";
90 $self->{max_buckets} = 16;
93 if ( !$self->{digest} ) {
95 $self->{digest} = \&Digest::MD5::md5;
101 ################################################################################
105 my ($obj, $key) = @_;
107 # This will be a Reference sector
108 my $sector = $self->_load_sector( $obj->_base_offset )
109 or die "How did read_value fail (no sector for '$obj')?!\n";
111 my $key_md5 = $self->_apply_digest( $key );
113 my $value_sector = $sector->get_data_for({
118 unless ( $value_sector ) {
119 $value_sector = DBM::Deep::Engine::Sector::Null->new({
124 $sector->write_data({
127 value => $value_sector,
131 return $value_sector->data;
138 # This will be a Reference sector
139 my $sector = $self->_load_sector( $obj->_base_offset )
140 or die "How did read_value fail (no sector for '$obj')?!\n";
142 return $sector->get_classname;
147 my ($obj, $key) = @_;
149 # This will be a Reference sector
150 my $sector = $self->_load_sector( $obj->_base_offset )
151 or die "How did key_exists fail (no sector for '$obj')?!\n";
153 my $data = $sector->get_data_for({
154 key_md5 => $self->_apply_digest( $key ),
158 # exists() returns 1 or '' for true/false.
159 return $data ? 1 : '';
164 my ($obj, $key) = @_;
166 my $sector = $self->_load_sector( $obj->_base_offset )
167 or die "How did delete_key fail (no sector for '$obj')?!\n";
169 return $sector->delete_key({
170 key_md5 => $self->_apply_digest( $key ),
177 my ($obj, $key, $value) = @_;
179 my $r = Scalar::Util::reftype( $value ) || '';
182 last if $r eq 'HASH';
183 last if $r eq 'ARRAY';
185 DBM::Deep->_throw_error(
186 "Storage of references of type '$r' is not supported."
191 if ( !defined $value ) {
192 $class = 'DBM::Deep::Engine::Sector::Null';
194 elsif ( $r eq 'ARRAY' || $r eq 'HASH' ) {
195 if ( $r eq 'ARRAY' && tied(@$value) ) {
196 DBM::Deep->_throw_error( "Cannot store something that is tied." );
198 if ( $r eq 'HASH' && tied(%$value) ) {
199 DBM::Deep->_throw_error( "Cannot store something that is tied." );
201 $class = 'DBM::Deep::Engine::Sector::Reference';
202 $type = substr( $r, 0, 1 );
205 $class = 'DBM::Deep::Engine::Sector::Scalar';
208 # This will be a Reference sector
209 my $sector = $self->_load_sector( $obj->_base_offset )
210 or die "How did write_value fail (no sector for '$obj')?!\n";
212 # Create this after loading the reference sector in case something bad happens.
213 # This way, we won't allocate value sector(s) needlessly.
214 my $value_sector = $class->new({
220 $sector->write_data({
222 key_md5 => $self->_apply_digest( $key ),
223 value => $value_sector,
226 # This code is to make sure we write all the values in the $value to the disk
227 # and to make sure all changes to $value after the assignment are reflected
228 # on disk. This may be counter-intuitive at first, but it is correct dwimmery.
229 # NOTE - simply tying $value won't perform a STORE on each value. Hence, the
230 # copy to a temp value.
231 if ( $r eq 'ARRAY' ) {
233 tie @$value, 'DBM::Deep', {
234 base_offset => $value_sector->offset,
235 storage => $self->storage,
239 bless $value, 'DBM::Deep::Array' unless Scalar::Util::blessed( $value );
241 elsif ( $r eq 'HASH' ) {
243 tie %$value, 'DBM::Deep', {
244 base_offset => $value_sector->offset,
245 storage => $self->storage,
250 bless $value, 'DBM::Deep::Hash' unless Scalar::Util::blessed( $value );
258 my ($obj, $prev_key) = @_;
260 # XXX Need to add logic about resetting the iterator if any key in the reference has changed
261 unless ( $prev_key ) {
262 $obj->{iterator} = DBM::Deep::Engine::Iterator->new({
263 base_offset => $obj->_base_offset,
268 return $obj->{iterator}->get_next_key;
271 ################################################################################
277 # We're opening the file.
278 unless ( $obj->_base_offset ) {
279 my $bytes_read = $self->_read_file_header;
281 # Creating a new file
282 unless ( $bytes_read ) {
283 $self->_write_file_header;
285 # 1) Create Array/Hash entry
286 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
290 $obj->{base_offset} = $initial_reference->offset;
292 $self->storage->flush;
294 # Reading from an existing file
296 $obj->{base_offset} = $bytes_read;
297 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
299 offset => $obj->_base_offset,
301 unless ( $initial_reference ) {
302 DBM::Deep->_throw_error("Corrupted file, no master index record");
305 unless ($obj->_type eq $initial_reference->type) {
306 DBM::Deep->_throw_error("File type mismatch");
318 if ( $self->trans_id ) {
319 DBM::Deep->_throw_error( "Cannot begin_work within a transaction" );
322 my @slots = $self->read_transaction_slots;
323 for my $i ( 1 .. @slots ) {
326 $self->set_trans_id( $i );
329 $self->write_transaction_slots( @slots );
331 if ( !$self->trans_id ) {
332 DBM::Deep->_throw_error( "Cannot begin_work - no available transactions" );
342 if ( !$self->trans_id ) {
343 DBM::Deep->_throw_error( "Cannot rollback without a transaction" );
346 # Each entry is the file location for a bucket that has a modification for
347 # this transaction. The entries need to be expunged.
348 foreach my $entry (@{ $self->get_entries } ) {
349 # Remove the entry here
350 my $read_loc = $entry
353 + $self->trans_id * $self->byte_size;
355 my $data_loc = $self->storage->read_at( $read_loc, $self->byte_size );
356 $data_loc = unpack( $StP{$self->byte_size}, $data_loc );
357 $self->storage->print_at( $read_loc, pack( $StP{$self->byte_size}, 0 ) );
359 if ( $data_loc > 1 ) {
360 $self->_load_sector( $data_loc )->free;
364 $self->clear_entries;
366 my @slots = $self->read_transaction_slots;
367 $slots[$self->trans_id] = 0;
368 $self->write_transaction_slots( @slots );
369 $self->set_trans_id( 0 );
378 if ( !$self->trans_id ) {
379 DBM::Deep->_throw_error( "Cannot commit without a transaction" );
382 print "TID: " . $self->trans_id, $/;
383 foreach my $entry (@{ $self->get_entries } ) {
385 # Overwrite the entry in head with the entry in trans_id
390 my $head_loc = $self->storage->read_at( $base, $self->byte_size );
391 $head_loc = unpack( $StP{$self->byte_size}, $head_loc );
392 my $trans_loc = $self->storage->read_at(
393 $base + $self->trans_id * $self->byte_size, $self->byte_size,
396 $self->storage->print_at( $base, $trans_loc );
397 $self->storage->print_at(
398 $base + $self->trans_id * $self->byte_size,
399 pack( $StP{$self->byte_size}, 0 ),
402 if ( $head_loc > 1 ) {
403 $self->_load_sector( $head_loc )->free;
407 $self->clear_entries;
409 my @slots = $self->read_transaction_slots;
410 $slots[$self->trans_id] = 0;
411 $self->write_transaction_slots( @slots );
412 $self->set_trans_id( 0 );
417 sub read_transaction_slots {
419 return split '', unpack( "b32", $self->storage->read_at( $self->trans_loc, 4 ) );
422 sub write_transaction_slots {
424 $self->storage->print_at( $self->trans_loc,
425 pack( "b32", join('', @_) ),
431 return [ keys %{ $self->{entries}{$self->trans_id} ||= {} } ];
436 my ($trans_id, $loc) = @_;
438 print "$trans_id => $loc\n";
439 $self->{entries}{$trans_id} ||= {};
440 $self->{entries}{$trans_id}{$loc} = undef;
441 use Data::Dumper;print "$self: " . Dumper $self->{entries};
447 delete $self->{entries}{$self->trans_id};
450 ################################################################################
453 my $header_fixed = length( SIG_FILE ) + 1 + 4 + 4;
455 sub _write_file_header {
458 my $header_var = 1 + 1 + 4 + 2 * $self->byte_size;
460 my $loc = $self->storage->request_space( $header_fixed + $header_var );
462 $self->storage->print_at( $loc,
465 pack('N', 1), # header version - at this point, we're at 9 bytes
466 pack('N', $header_var), # header size
467 # --- Above is $header_fixed. Below is $header_var
468 pack('C', $self->byte_size),
469 pack('C', $self->max_buckets),
470 pack('N', 0 ), # Running transactions
471 pack($StP{$self->byte_size}, 0), # Start of free chain (blist size)
472 pack($StP{$self->byte_size}, 0), # Start of free chain (data size)
475 $self->set_trans_loc( $header_fixed + 2 );
476 $self->set_chains_loc( $header_fixed + 6 );
481 sub _read_file_header {
484 my $buffer = $self->storage->read_at( 0, $header_fixed );
485 return unless length($buffer);
487 my ($file_signature, $sig_header, $header_version, $size) = unpack(
491 unless ( $file_signature eq SIG_FILE ) {
492 $self->storage->close;
493 DBM::Deep->_throw_error( "Signature not found -- file is not a Deep DB" );
496 unless ( $sig_header eq SIG_HEADER ) {
497 $self->storage->close;
498 DBM::Deep->_throw_error( "Old file version found." );
501 my $buffer2 = $self->storage->read_at( undef, $size );
502 my @values = unpack( 'C C', $buffer2 );
504 $self->set_trans_loc( $header_fixed + 2 );
505 $self->set_chains_loc( $header_fixed + 6 );
507 if ( @values < 2 || grep { !defined } @values ) {
508 $self->storage->close;
509 DBM::Deep->_throw_error("Corrupted file - bad header");
512 #XXX Add warnings if values weren't set right
513 @{$self}{qw(byte_size max_buckets)} = @values;
515 my $header_var = 1 + 1 + 4 + 2 * $self->byte_size;
516 unless ( $size eq $header_var ) {
517 $self->storage->close;
518 DBM::Deep->_throw_error( "Unexpected size found ($size <-> $header_var)." );
521 return length($buffer) + length($buffer2);
529 my $type = $self->storage->read_at( $offset, 1 );
530 return if $type eq chr(0);
532 if ( $type eq $self->SIG_ARRAY || $type eq $self->SIG_HASH ) {
533 return DBM::Deep::Engine::Sector::Reference->new({
539 # XXX Don't we need key_md5 here?
540 elsif ( $type eq $self->SIG_BLIST ) {
541 return DBM::Deep::Engine::Sector::BucketList->new({
547 elsif ( $type eq $self->SIG_NULL ) {
548 return DBM::Deep::Engine::Sector::Null->new({
554 elsif ( $type eq $self->SIG_DATA ) {
555 return DBM::Deep::Engine::Sector::Scalar->new({
561 # This was deleted from under us, so just return and let the caller figure it out.
562 elsif ( $type eq $self->SIG_FREE ) {
566 die "'$offset': Don't know what to do with type '$type'\n";
571 return $self->{digest}->(@_);
574 sub _add_free_sector {
576 my ($offset, $size) = @_;
580 if ( $size == 256 ) {
581 $chains_offset = $self->byte_size;
588 my $old_head = $self->storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
590 $self->storage->print_at( $self->chains_loc + $chains_offset,
591 pack( $StP{$self->byte_size}, $offset ),
594 # Record the old head in the new sector after the signature
595 $self->storage->print_at( $offset + 1, $old_head );
598 sub _request_sector {
604 if ( $size == 256 ) {
605 $chains_offset = $self->byte_size;
612 my $old_head = $self->storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
613 my $loc = unpack( $StP{$self->byte_size}, $old_head );
615 # We don't have any free sectors of the right size, so allocate a new one.
617 return $self->storage->request_space( $size );
620 my $new_head = $self->storage->read_at( $loc + 1, $self->byte_size );
621 $self->storage->print_at( $self->chains_loc + $chains_offset, $new_head );
626 ################################################################################
628 sub storage { $_[0]{storage} }
629 sub byte_size { $_[0]{byte_size} }
630 sub hash_size { $_[0]{hash_size} }
631 sub num_txns { $_[0]{num_txns} }
632 sub max_buckets { $_[0]{max_buckets} }
633 sub blank_md5 { chr(0) x $_[0]->hash_size }
635 sub trans_id { $_[0]{trans_id} }
636 sub set_trans_id { $_[0]{trans_id} = $_[1] }
638 sub trans_loc { $_[0]{trans_loc} }
639 sub set_trans_loc { $_[0]{trans_loc} = $_[1] }
641 sub chains_loc { $_[0]{chains_loc} }
642 sub set_chains_loc { $_[0]{chains_loc} = $_[1] }
644 ################################################################################
646 package DBM::Deep::Engine::Iterator;
654 engine => $args->{engine},
655 base_offset => $args->{base_offset},
658 Scalar::Util::weaken( $self->{engine} );
665 $self->{breadcrumbs} = [];
671 my $crumbs = $self->{breadcrumbs};
673 unless ( @$crumbs ) {
674 # This will be a Reference sector
675 my $sector = $self->{engine}->_load_sector( $self->{base_offset} )
676 # or die "Iterator: How did this fail (no ref sector for '$self->{base_offset}')?!\n";
677 # If no sector is found, thist must have been deleted from under us.
679 push @$crumbs, [ $sector->get_blist_loc, 0 ];
684 my ($offset, $idx) = @{ $crumbs->[-1] };
690 if ( $idx >= $self->{engine}->max_buckets ) {
695 my $sector = $self->{engine}->_load_sector( $offset )
696 or die "Iterator: How did this fail (no blist sector for '$offset')?!\n";
698 #XXX Think this through!
699 my $loc = $sector->get_data_location_for({
707 my $key_sector = $sector->get_key_for( $idx );
708 unless ( $key_sector ) {
714 $key = $key_sector->data;
721 package DBM::Deep::Engine::Sector;
724 my $self = bless $_[1], $_[0];
725 Scalar::Util::weaken( $self->{engine} );
730 sub clone { die "Must be implemented in the child class" }
732 sub engine { $_[0]{engine} }
733 sub offset { $_[0]{offset} }
734 sub type { $_[0]{type} }
739 $self->engine->storage->print_at( $self->offset,
740 $self->engine->SIG_FREE,
741 chr(0) x ($self->size - 1),
744 $self->engine->_add_free_sector(
745 $self->offset, $self->size,
751 package DBM::Deep::Engine::Sector::Data;
753 our @ISA = qw( DBM::Deep::Engine::Sector );
756 sub size { return 256 }
760 return ref($self)->new({
761 engine => $self->engine,
767 package DBM::Deep::Engine::Sector::Scalar;
769 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
774 my $chain_loc = $self->chain_loc;
776 $self->SUPER::free();
779 $self->engine->_load_sector( $chain_loc )->free;
785 sub type { $_[0]{engine}->SIG_DATA }
789 my $engine = $self->engine;
791 unless ( $self->offset ) {
792 my $data_section = $self->size - 3 - 1 * $engine->byte_size;
794 $self->{offset} = $engine->_request_sector( $self->size );
796 my $data = delete $self->{data};
797 my $dlen = length $data;
799 my $curr_offset = $self->offset;
800 while ( $continue ) {
804 my ($leftover, $this_len, $chunk);
805 if ( $dlen > $data_section ) {
807 $this_len = $data_section;
808 $chunk = substr( $data, 0, $this_len );
810 $dlen -= $data_section;
811 $next_offset = $engine->_request_sector( $self->size );
812 $data = substr( $data, $this_len );
815 $leftover = $data_section - $dlen;
822 $engine->storage->print_at( $curr_offset,
823 $self->type, # Sector type
824 pack( $StP{1}, 0 ), # Recycled counter
825 pack( $StP{$engine->byte_size}, $next_offset ), # Chain loc
826 pack( $StP{1}, $this_len ), # Data length
827 $chunk, # Data to be stored in this sector
828 chr(0) x $leftover, # Zero-fill the rest
831 $curr_offset = $next_offset;
841 my $buffer = $self->engine->storage->read_at(
842 $self->offset + 2 + $self->engine->byte_size, 1
845 return unpack( $StP{1}, $buffer );
850 my $chain_loc = $self->engine->storage->read_at(
851 $self->offset + 2, $self->engine->byte_size,
853 return unpack( $StP{$self->engine->byte_size}, $chain_loc );
861 my $chain_loc = $self->chain_loc;
863 $data .= $self->engine->storage->read_at(
864 $self->offset + 2 + $self->engine->byte_size + 1, $self->data_length,
867 last unless $chain_loc;
869 $self = $self->engine->_load_sector( $chain_loc );
875 package DBM::Deep::Engine::Sector::Null;
877 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
879 sub type { $_[0]{engine}->SIG_NULL }
880 sub data_length { 0 }
886 my $engine = $self->engine;
888 unless ( $self->offset ) {
889 my $leftover = $self->size - 3 - 1 * $engine->byte_size;
891 $self->{offset} = $engine->_request_sector( $self->size );
892 $engine->storage->print_at( $self->offset,
893 $self->type, # Sector type
894 pack( $StP{1}, 0 ), # Recycled counter
895 pack( $StP{$engine->byte_size}, 0 ), # Chain loc
896 pack( $StP{1}, $self->data_length ), # Data length
897 chr(0) x $leftover, # Zero-fill the rest
904 package DBM::Deep::Engine::Sector::Reference;
906 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
911 my $engine = $self->engine;
913 unless ( $self->offset ) {
914 my $classname = Scalar::Util::blessed( delete $self->{data} );
915 my $leftover = $self->size - 4 - 2 * $engine->byte_size;
917 my $class_offset = 0;
918 if ( defined $classname ) {
919 my $class_sector = DBM::Deep::Engine::Sector::Scalar->new({
920 engine => $self->engine,
923 $class_offset = $class_sector->offset;
926 $self->{offset} = $engine->_request_sector( $self->size );
927 $engine->storage->print_at( $self->offset,
928 $self->type, # Sector type
929 pack( $StP{1}, 0 ), # Recycled counter
930 pack( $StP{$engine->byte_size}, 0 ), # Index/BList loc
931 pack( $StP{$engine->byte_size}, $class_offset ), # Classname loc
932 chr(0) x $leftover, # Zero-fill the rest
938 $self->{type} = $engine->storage->read_at( $self->offset, 1 );
947 # Assume that the head is not allowed unless otherwise specified.
948 $args->{allow_head} = 0 unless exists $args->{allow_head};
950 # Assume we don't create a new blist location unless otherwise specified.
951 $args->{create} = 0 unless exists $args->{create};
953 my $blist = $self->get_bucket_list({
954 key_md5 => $args->{key_md5},
955 create => $args->{create},
957 return unless $blist && $blist->{found};
959 # At this point, $blist knows where the md5 is. What it -doesn't- know yet
960 # is whether or not this transaction has this key. That's part of the next
962 my $location = $blist->get_data_location_for({
963 allow_head => $args->{allow_head},
966 return $self->engine->_load_sector( $location );
973 my $blist = $self->get_bucket_list({
974 key_md5 => $args->{key_md5},
976 }) or die "How did write_data fail (no blist)?!\n";
978 # Handle any transactional bookkeeping.
979 if ( $self->engine->trans_id ) {
980 if ( ! $blist->{found} ) {
981 $blist->mark_deleted({
987 my @transactions = $self->engine->read_transaction_slots;
988 my @trans_ids = grep { $transactions[$_] } 0 .. $#transactions;
989 if ( $blist->{found} ) {
991 my $old_value = $blist->get_data_for;
992 foreach my $other_trans_id ( @trans_ids ) {
993 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
994 print "write_md5 to save a value\n";
996 trans_id => $other_trans_id,
998 key_md5 => $args->{key_md5},
999 value => $old_value->clone,
1006 foreach my $other_trans_id ( @trans_ids ) {
1007 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1008 $blist->mark_deleted({
1009 trans_id => $other_trans_id,
1016 #XXX Is this safe to do transactionally?
1017 # Free the place we're about to write to.
1018 if ( $blist->get_data_location_for({ allow_head => 0 }) ) {
1019 $blist->get_data_for({ allow_head => 0 })->free;
1023 key => $args->{key},
1024 key_md5 => $args->{key_md5},
1025 value => $args->{value},
1033 # XXX What should happen if this fails?
1034 my $blist = $self->get_bucket_list({
1035 key_md5 => $args->{key_md5},
1036 }) or die "How did delete_key fail (no blist)?!\n";
1038 # Save the location so that we can free the data
1039 my $location = $blist->get_data_location_for({
1042 my $old_value = $self->engine->_load_sector( $location );
1044 if ( $self->engine->trans_id == 0 ) {
1045 my @transactions = $self->engine->read_transaction_slots;
1046 my @trans_ids = grep { $transactions[$_] } 0 .. $#transactions;
1048 foreach my $other_trans_id ( @trans_ids ) {
1049 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1051 trans_id => $other_trans_id,
1052 key => $args->{key},
1053 key_md5 => $args->{key_md5},
1054 value => $old_value->clone,
1060 $blist->mark_deleted( $args );
1062 my $data = $old_value->data;
1071 my $e = $self->engine;
1072 my $blist_loc = $e->storage->read_at( $self->offset + 2, $e->byte_size );
1073 return unpack( $StP{$e->byte_size}, $blist_loc );
1076 sub get_bucket_list {
1081 # XXX Add in check here for recycling?
1083 my $engine = $self->engine;
1085 my $blist_loc = $self->get_blist_loc;
1087 # There's no index or blist yet
1088 unless ( $blist_loc ) {
1089 return unless $args->{create};
1091 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1093 key_md5 => $args->{key_md5},
1096 $engine->storage->print_at( $self->offset + 2,
1097 pack( $StP{$engine->byte_size}, $blist->offset ),
1103 return DBM::Deep::Engine::Sector::BucketList->new({
1105 offset => $blist_loc,
1106 key_md5 => $args->{key_md5},
1113 my $class_offset = $self->engine->storage->read_at(
1114 $self->offset + 2 + 1 * $self->engine->byte_size, $self->engine->byte_size,
1116 $class_offset = unpack ( $StP{$self->engine->byte_size}, $class_offset );
1118 return unless $class_offset;
1120 return $self->engine->_load_sector( $class_offset )->data;
1126 my $new_obj = DBM::Deep->new({
1127 type => $self->type,
1128 base_offset => $self->offset,
1129 storage => $self->engine->storage,
1130 engine => $self->engine,
1133 if ( $self->engine->storage->{autobless} ) {
1134 my $classname = $self->get_classname;
1135 if ( defined $classname ) {
1136 bless $new_obj, $classname;
1143 package DBM::Deep::Engine::Sector::BucketList;
1145 our @ISA = qw( DBM::Deep::Engine::Sector );
1147 sub idx_for_txn { return $_[1] + 1 }
1152 my $engine = $self->engine;
1154 unless ( $self->offset ) {
1155 my $leftover = $self->size - $self->base_size;
1157 $self->{offset} = $engine->_request_sector( $self->size );
1158 $engine->storage->print_at( $self->offset,
1159 $engine->SIG_BLIST, # Sector type
1160 pack( $StP{1}, 0 ), # Recycled counter
1161 chr(0) x $leftover, # Zero-fill the data
1165 if ( $self->{key_md5} ) {
1172 sub base_size { 2 } # Sig + recycled counter
1176 unless ( $self->{size} ) {
1177 my $e = $self->engine;
1178 $self->{size} = $self->base_size + $e->max_buckets * $self->bucket_size; # Base + numbuckets * bucketsize
1180 return $self->{size};
1185 unless ( $self->{bucket_size} ) {
1186 my $e = $self->engine;
1187 # Key + transactions
1188 my $locs_size = (1 + $e->num_txns ) * $e->byte_size;
1189 $self->{bucket_size} = $e->hash_size + $locs_size;
1191 return $self->{bucket_size};
1196 unless ( exists $self->{found} ) {
1199 return $self->{found};
1205 $self->{found} = undef;
1208 # If we don't have an MD5, then what are we supposed to do?
1209 unless ( exists $self->{key_md5} ) {
1210 DBM::Deep->_throw_error( "Cannot find_md5 without a key_md5 set" );
1213 my $e = $self->engine;
1214 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
1215 my $potential = $e->storage->read_at(
1216 $self->offset + $self->base_size + $idx * $self->bucket_size, $e->hash_size,
1219 if ( $potential eq $e->blank_md5 ) {
1220 $self->{idx} = $idx;
1224 if ( $potential eq $self->{key_md5} ) {
1226 $self->{idx} = $idx;
1238 DBM::Deep->_throw_error( "write_md5: no key" ) unless exists $args->{key};
1239 DBM::Deep->_throw_error( "write_md5: no key_md5" ) unless exists $args->{key_md5};
1240 DBM::Deep->_throw_error( "write_md5: no value" ) unless exists $args->{value};
1242 my $engine = $self->engine;
1244 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
1246 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1247 print "Adding $args->{trans_id} -> $spot\n";
1248 $engine->add_entry( $args->{trans_id}, $spot );
1250 unless ($self->{found}) {
1251 my $key_sector = DBM::Deep::Engine::Sector::Scalar->new({
1253 data => $args->{key},
1256 $engine->storage->print_at( $spot,
1258 pack( $StP{$engine->byte_size}, $key_sector->offset ),
1263 + $engine->hash_size
1264 + $engine->byte_size
1265 + $args->{trans_id} * $engine->byte_size;
1267 $engine->storage->print_at( $loc,
1268 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
1277 my $engine = $self->engine;
1279 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
1281 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1282 $engine->add_entry( $args->{trans_id}, $spot );
1285 + $engine->hash_size
1286 + $engine->byte_size
1287 + $args->{trans_id} * $engine->byte_size;
1289 $engine->storage->print_at( $loc,
1290 pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
1298 my $engine = $self->engine;
1299 return undef unless $self->{found};
1301 # Save the location so that we can free the data
1302 my $location = $self->get_data_location_for({
1305 my $key_sector = $self->get_key_for;
1307 #XXX This isn't going to work right and you know it! This eradicates data
1308 # that we're not ready to eradicate just yet.
1309 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1310 $engine->storage->print_at( $spot,
1311 $engine->storage->read_at(
1312 $spot + $self->bucket_size,
1313 $self->bucket_size * ( $engine->num_txns - $self->{idx} - 1 ),
1315 chr(0) x $self->bucket_size,
1320 my $data_sector = $self->engine->_load_sector( $location );
1321 my $data = $data_sector->data;
1327 sub get_data_location_for {
1332 $args->{allow_head} = 0 unless exists $args->{allow_head};
1333 $args->{trans_id} = $self->engine->trans_id unless exists $args->{trans_id};
1334 $args->{idx} = $self->{idx} unless exists $args->{idx};
1336 my $location = $self->engine->storage->read_at(
1337 $self->offset + $self->base_size
1338 + $args->{idx} * $self->bucket_size
1339 + $self->engine->hash_size
1340 + $self->engine->byte_size
1341 + $args->{trans_id} * $self->engine->byte_size,
1342 $self->engine->byte_size,
1344 my $loc = unpack( $StP{$self->engine->byte_size}, $location );
1346 # If we're in a transaction and we never wrote to this location, try the
1348 if ( $args->{trans_id} && !$loc && $args->{allow_head} ) {
1349 return $self->get_data_location_for({
1354 return $loc <= 1 ? 0 : $loc;
1362 return unless $self->{found};
1363 my $location = $self->get_data_location_for({
1364 allow_head => $args->{allow_head},
1366 return $self->engine->_load_sector( $location );
1372 $idx = $self->{idx} unless defined $idx;
1374 my $location = $self->engine->storage->read_at(
1375 $self->offset + $self->base_size + $idx * $self->bucket_size + $self->engine->hash_size,
1376 $self->engine->byte_size,
1378 $location = unpack( $StP{$self->engine->byte_size}, $location );
1379 return unless $location;
1380 return $self->engine->_load_sector( $location );