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 (no order specified, presumably ASCII)
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)
49 hash_size => 16, # In bytes
51 num_txns => 16, # HEAD plus 15 running txns
52 trans_id => 0, # Default to the HEAD
54 entries => {}, # This is the list of entries for transactions
58 if ( defined $args->{pack_size} ) {
59 if ( lc $args->{pack_size} eq 'small' ) {
60 $args->{byte_size} = 2;
62 elsif ( lc $args->{pack_size} eq 'medium' ) {
63 $args->{byte_size} = 4;
65 elsif ( lc $args->{pack_size} eq 'large' ) {
66 $args->{byte_size} = 8;
69 die "Unknown pack_size value: '$args->{pack_size}'\n";
73 # Grab the parameters we want to use
74 foreach my $param ( keys %$self ) {
75 next unless exists $args->{$param};
76 $self->{$param} = $args->{$param};
79 $self->{byte_pack} = $StP{ $self->byte_size };
82 # Number of buckets per blist before another level of indexing is
83 # done. Increase this value for slightly greater speed, but larger database
84 # files. DO NOT decrease this value below 16, due to risk of recursive
87 if ( $self->{max_buckets} < 16 ) {
88 warn "Floor of max_buckets is 16. Setting it to 16 from '$self->{max_buckets}'\n";
89 $self->{max_buckets} = 16;
92 if ( !$self->{digest} ) {
94 $self->{digest} = \&Digest::MD5::md5;
100 ################################################################################
104 my ($obj, $key) = @_;
106 # This will be a Reference sector
107 my $sector = $self->_load_sector( $obj->_base_offset )
110 my $key_md5 = $self->_apply_digest( $key );
112 my $value_sector = $sector->get_data_for({
117 unless ( $value_sector ) {
118 $value_sector = DBM::Deep::Engine::Sector::Null->new({
123 $sector->write_data({
126 value => $value_sector,
130 return $value_sector->data;
137 # This will be a Reference sector
138 my $sector = $self->_load_sector( $obj->_base_offset )
139 or die "How did get_classname fail (no sector for '$obj')?!\n";
141 return $sector->get_classname;
146 my ($obj, $key) = @_;
148 # This will be a Reference sector
149 my $sector = $self->_load_sector( $obj->_base_offset )
152 my $data = $sector->get_data_for({
153 key_md5 => $self->_apply_digest( $key ),
157 # exists() returns 1 or '' for true/false.
158 return $data ? 1 : '';
163 my ($obj, $key) = @_;
165 my $sector = $self->_load_sector( $obj->_base_offset )
168 return $sector->delete_key({
169 key_md5 => $self->_apply_digest( $key ),
176 my ($obj, $key, $value) = @_;
178 my $r = Scalar::Util::reftype( $value ) || '';
181 last if $r eq 'HASH';
182 last if $r eq 'ARRAY';
184 DBM::Deep->_throw_error(
185 "Storage of references of type '$r' is not supported."
190 if ( !defined $value ) {
191 $class = 'DBM::Deep::Engine::Sector::Null';
193 elsif ( $r eq 'ARRAY' || $r eq 'HASH' ) {
194 if ( $r eq 'ARRAY' && tied(@$value) ) {
195 DBM::Deep->_throw_error( "Cannot store something that is tied." );
197 if ( $r eq 'HASH' && tied(%$value) ) {
198 DBM::Deep->_throw_error( "Cannot store something that is tied." );
200 $class = 'DBM::Deep::Engine::Sector::Reference';
201 $type = substr( $r, 0, 1 );
204 $class = 'DBM::Deep::Engine::Sector::Scalar';
207 # This will be a Reference sector
208 my $sector = $self->_load_sector( $obj->_base_offset )
209 or die "Cannot write to a deleted spot in DBM::Deep.\n";
211 # Create this after loading the reference sector in case something bad happens.
212 # This way, we won't allocate value sector(s) needlessly.
213 my $value_sector = $class->new({
219 $sector->write_data({
221 key_md5 => $self->_apply_digest( $key ),
222 value => $value_sector,
225 # This code is to make sure we write all the values in the $value to the disk
226 # and to make sure all changes to $value after the assignment are reflected
227 # on disk. This may be counter-intuitive at first, but it is correct dwimmery.
228 # NOTE - simply tying $value won't perform a STORE on each value. Hence, the
229 # copy to a temp value.
230 if ( $r eq 'ARRAY' ) {
232 tie @$value, 'DBM::Deep', {
233 base_offset => $value_sector->offset,
234 storage => $self->storage,
238 bless $value, 'DBM::Deep::Array' unless Scalar::Util::blessed( $value );
240 elsif ( $r eq 'HASH' ) {
242 tie %$value, 'DBM::Deep', {
243 base_offset => $value_sector->offset,
244 storage => $self->storage,
249 bless $value, 'DBM::Deep::Hash' unless Scalar::Util::blessed( $value );
257 my ($obj, $prev_key) = @_;
259 # XXX Need to add logic about resetting the iterator if any key in the reference has changed
260 unless ( $prev_key ) {
261 $obj->{iterator} = DBM::Deep::Engine::Iterator->new({
262 base_offset => $obj->_base_offset,
267 return $obj->{iterator}->get_next_key;
270 ################################################################################
276 # We're opening the file.
277 unless ( $obj->_base_offset ) {
278 my $bytes_read = $self->_read_file_header;
280 # Creating a new file
281 unless ( $bytes_read ) {
282 $self->_write_file_header;
284 # 1) Create Array/Hash entry
285 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
289 $obj->{base_offset} = $initial_reference->offset;
291 $self->storage->flush;
293 # Reading from an existing file
295 $obj->{base_offset} = $bytes_read;
296 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
298 offset => $obj->_base_offset,
300 unless ( $initial_reference ) {
301 DBM::Deep->_throw_error("Corrupted file, no master index record");
304 unless ($obj->_type eq $initial_reference->type) {
305 DBM::Deep->_throw_error("File type mismatch");
317 if ( $self->trans_id ) {
318 DBM::Deep->_throw_error( "Cannot begin_work within a transaction" );
321 my @slots = $self->read_txn_slots;
322 for my $i ( 1 .. @slots ) {
325 $self->set_trans_id( $i );
328 $self->write_txn_slots( @slots );
330 if ( !$self->trans_id ) {
331 DBM::Deep->_throw_error( "Cannot begin_work - no available transactions" );
341 if ( !$self->trans_id ) {
342 DBM::Deep->_throw_error( "Cannot rollback without a transaction" );
345 # Each entry is the file location for a bucket that has a modification for
346 # this transaction. The entries need to be expunged.
347 foreach my $entry (@{ $self->get_entries } ) {
348 # Remove the entry here
349 my $read_loc = $entry
352 + $self->trans_id * ( $self->byte_size + 4 );
354 my $data_loc = $self->storage->read_at( $read_loc, $self->byte_size );
355 $data_loc = unpack( $StP{$self->byte_size}, $data_loc );
356 $self->storage->print_at( $read_loc, pack( $StP{$self->byte_size}, 0 ) );
358 if ( $data_loc > 1 ) {
359 $self->_load_sector( $data_loc )->free;
363 $self->clear_entries;
365 my @slots = $self->read_txn_slots;
366 $slots[$self->trans_id] = 0;
367 $self->write_txn_slots( @slots );
368 $self->inc_txn_staleness_counter( $self->trans_id );
369 $self->set_trans_id( 0 );
378 if ( !$self->trans_id ) {
379 DBM::Deep->_throw_error( "Cannot commit without a transaction" );
382 foreach my $entry (@{ $self->get_entries } ) {
383 # Overwrite the entry in head with the entry in trans_id
388 my $head_loc = $self->storage->read_at( $base, $self->byte_size );
389 $head_loc = unpack( $StP{$self->byte_size}, $head_loc );
390 my $trans_loc = $self->storage->read_at(
391 $base + $self->trans_id * ( $self->byte_size + 4 ), $self->byte_size,
394 $self->storage->print_at( $base, $trans_loc );
395 $self->storage->print_at(
396 $base + $self->trans_id * ( $self->byte_size + 4 ),
397 pack( $StP{$self->byte_size} . ' N', (0) x 2 ),
400 if ( $head_loc > 1 ) {
401 $self->_load_sector( $head_loc )->free;
405 $self->clear_entries;
407 my @slots = $self->read_txn_slots;
408 $slots[$self->trans_id] = 0;
409 $self->write_txn_slots( @slots );
410 $self->inc_txn_staleness_counter( $self->trans_id );
411 $self->set_trans_id( 0 );
418 return split '', unpack( 'b32',
419 $self->storage->read_at(
425 sub write_txn_slots {
427 $self->storage->print_at( $self->trans_loc,
428 pack( 'b32', join('', @_) ),
432 sub get_running_txn_ids {
434 my @transactions = $self->read_txn_slots;
435 my @trans_ids = grep { $transactions[$_] } 0 .. $#transactions;
438 sub get_txn_staleness_counter {
442 # Hardcode staleness of 0 for the HEAD
443 return 0 unless $trans_id;
446 $self->storage->read_at(
447 $self->trans_loc + 4 * $trans_id,
454 sub inc_txn_staleness_counter {
458 # Hardcode staleness of 0 for the HEAD
459 return unless $trans_id;
461 $self->storage->print_at(
462 $self->trans_loc + 4 * $trans_id,
463 pack( 'N', $self->get_txn_staleness_counter( $trans_id ) + 1 ),
469 return [ keys %{ $self->{entries}{$self->trans_id} ||= {} } ];
474 my ($trans_id, $loc) = @_;
476 $self->{entries}{$trans_id} ||= {};
477 $self->{entries}{$trans_id}{$loc} = undef;
482 delete $self->{entries}{$self->trans_id};
485 ################################################################################
488 my $header_fixed = length( SIG_FILE ) + 1 + 4 + 4;
490 sub _write_file_header {
493 my $header_var = 1 + 1 + 4 + 4 * $self->num_txns + 2 * $self->byte_size;
495 my $loc = $self->storage->request_space( $header_fixed + $header_var );
497 $self->storage->print_at( $loc,
500 pack('N', 1), # header version - at this point, we're at 9 bytes
501 pack('N', $header_var), # header size
502 # --- Above is $header_fixed. Below is $header_var
503 pack('C', $self->byte_size),
504 pack('C', $self->max_buckets),
505 pack('N', 0 ), # Transaction activeness bitfield
506 pack('N' . $self->num_txns, 0 x $self->num_txns ), # Transaction staleness counters
507 pack($StP{$self->byte_size}, 0), # Start of free chain (blist size)
508 pack($StP{$self->byte_size}, 0), # Start of free chain (data size)
511 $self->set_trans_loc( $header_fixed + 2 );
512 $self->set_chains_loc( $header_fixed + 2 + 4 + 4 * $self->num_txns );
517 sub _read_file_header {
520 my $buffer = $self->storage->read_at( 0, $header_fixed );
521 return unless length($buffer);
523 my ($file_signature, $sig_header, $header_version, $size) = unpack(
527 unless ( $file_signature eq SIG_FILE ) {
528 $self->storage->close;
529 DBM::Deep->_throw_error( "Signature not found -- file is not a Deep DB" );
532 unless ( $sig_header eq SIG_HEADER ) {
533 $self->storage->close;
534 DBM::Deep->_throw_error( "Old file version found." );
537 my $buffer2 = $self->storage->read_at( undef, $size );
538 my @values = unpack( 'C C', $buffer2 );
540 $self->set_trans_loc( $header_fixed + 2 );
541 $self->set_chains_loc( $header_fixed + 2 + 4 + 4 * $self->num_txns );
543 if ( @values < 2 || grep { !defined } @values ) {
544 $self->storage->close;
545 DBM::Deep->_throw_error("Corrupted file - bad header");
548 #XXX Add warnings if values weren't set right
549 @{$self}{qw(byte_size max_buckets)} = @values;
551 my $header_var = 1 + 1 + 4 + 4 * $self->num_txns + 2 * $self->byte_size;
552 unless ( $size eq $header_var ) {
553 $self->storage->close;
554 DBM::Deep->_throw_error( "Unexpected size found ($size <-> $header_var)." );
557 return length($buffer) + length($buffer2);
565 my $type = $self->storage->read_at( $offset, 1 );
566 return if $type eq chr(0);
568 if ( $type eq $self->SIG_ARRAY || $type eq $self->SIG_HASH ) {
569 return DBM::Deep::Engine::Sector::Reference->new({
575 # XXX Don't we need key_md5 here?
576 elsif ( $type eq $self->SIG_BLIST ) {
577 return DBM::Deep::Engine::Sector::BucketList->new({
583 elsif ( $type eq $self->SIG_NULL ) {
584 return DBM::Deep::Engine::Sector::Null->new({
590 elsif ( $type eq $self->SIG_DATA ) {
591 return DBM::Deep::Engine::Sector::Scalar->new({
597 # This was deleted from under us, so just return and let the caller figure it out.
598 elsif ( $type eq $self->SIG_FREE ) {
602 die "'$offset': Don't know what to do with type '$type'\n";
607 return $self->{digest}->(@_);
610 sub _add_free_sector {
612 my ($offset, $size) = @_;
616 if ( $size == 256 ) {
617 $chains_offset = $self->byte_size;
624 my $old_head = $self->storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
626 $self->storage->print_at( $self->chains_loc + $chains_offset,
627 pack( $StP{$self->byte_size}, $offset ),
630 # Record the old head in the new sector after the signature
631 $self->storage->print_at( $offset + 1, $old_head );
634 sub _request_sector {
640 if ( $size == 256 ) {
641 $chains_offset = $self->byte_size;
648 my $old_head = $self->storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
649 my $loc = unpack( $StP{$self->byte_size}, $old_head );
651 # We don't have any free sectors of the right size, so allocate a new one.
653 return $self->storage->request_space( $size );
656 my $new_head = $self->storage->read_at( $loc + 1, $self->byte_size );
657 $self->storage->print_at( $self->chains_loc + $chains_offset, $new_head );
662 ################################################################################
664 sub storage { $_[0]{storage} }
665 sub byte_size { $_[0]{byte_size} }
666 sub hash_size { $_[0]{hash_size} }
667 sub num_txns { $_[0]{num_txns} }
668 sub max_buckets { $_[0]{max_buckets} }
669 sub blank_md5 { chr(0) x $_[0]->hash_size }
671 sub trans_id { $_[0]{trans_id} }
672 sub set_trans_id { $_[0]{trans_id} = $_[1] }
674 sub trans_loc { $_[0]{trans_loc} }
675 sub set_trans_loc { $_[0]{trans_loc} = $_[1] }
677 sub chains_loc { $_[0]{chains_loc} }
678 sub set_chains_loc { $_[0]{chains_loc} = $_[1] }
680 ################################################################################
682 package DBM::Deep::Engine::Iterator;
690 engine => $args->{engine},
691 base_offset => $args->{base_offset},
694 Scalar::Util::weaken( $self->{engine} );
701 $self->{breadcrumbs} = [];
707 my $crumbs = $self->{breadcrumbs};
709 unless ( @$crumbs ) {
710 # This will be a Reference sector
711 my $sector = $self->{engine}->_load_sector( $self->{base_offset} )
712 # or die "Iterator: How did this fail (no ref sector for '$self->{base_offset}')?!\n";
713 # If no sector is found, thist must have been deleted from under us.
715 push @$crumbs, [ $sector->get_blist_loc, 0 ];
720 my ($offset, $idx) = @{ $crumbs->[-1] };
726 if ( $idx >= $self->{engine}->max_buckets ) {
731 my $sector = $self->{engine}->_load_sector( $offset )
732 or die "Iterator: How did this fail (no blist sector for '$offset')?!\n";
734 #XXX Think this through!
735 my $loc = $sector->get_data_location_for({
744 my $key_sector = $sector->get_key_for( $idx );
745 unless ( $key_sector ) {
751 $key = $key_sector->data;
758 package DBM::Deep::Engine::Sector;
761 my $self = bless $_[1], $_[0];
762 Scalar::Util::weaken( $self->{engine} );
767 sub clone { die "Must be implemented in the child class" }
769 sub engine { $_[0]{engine} }
770 sub offset { $_[0]{offset} }
771 sub type { $_[0]{type} }
776 $self->engine->storage->print_at( $self->offset,
777 $self->engine->SIG_FREE,
778 chr(0) x ($self->size - 1),
781 $self->engine->_add_free_sector(
782 $self->offset, $self->size,
788 package DBM::Deep::Engine::Sector::Data;
790 our @ISA = qw( DBM::Deep::Engine::Sector );
793 sub size { return 256 }
797 return ref($self)->new({
798 engine => $self->engine,
804 package DBM::Deep::Engine::Sector::Scalar;
806 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
811 my $chain_loc = $self->chain_loc;
813 $self->SUPER::free();
816 $self->engine->_load_sector( $chain_loc )->free;
822 sub type { $_[0]{engine}->SIG_DATA }
826 my $engine = $self->engine;
828 unless ( $self->offset ) {
829 my $data_section = $self->size - 3 - 1 * $engine->byte_size;
831 $self->{offset} = $engine->_request_sector( $self->size );
833 my $data = delete $self->{data};
834 my $dlen = length $data;
836 my $curr_offset = $self->offset;
837 while ( $continue ) {
841 my ($leftover, $this_len, $chunk);
842 if ( $dlen > $data_section ) {
844 $this_len = $data_section;
845 $chunk = substr( $data, 0, $this_len );
847 $dlen -= $data_section;
848 $next_offset = $engine->_request_sector( $self->size );
849 $data = substr( $data, $this_len );
852 $leftover = $data_section - $dlen;
859 $engine->storage->print_at( $curr_offset,
860 $self->type, # Sector type
861 pack( $StP{1}, 0 ), # Recycled counter
862 pack( $StP{$engine->byte_size}, $next_offset ), # Chain loc
863 pack( $StP{1}, $this_len ), # Data length
864 $chunk, # Data to be stored in this sector
865 chr(0) x $leftover, # Zero-fill the rest
868 $curr_offset = $next_offset;
878 my $buffer = $self->engine->storage->read_at(
879 $self->offset + 2 + $self->engine->byte_size, 1
882 return unpack( $StP{1}, $buffer );
887 my $chain_loc = $self->engine->storage->read_at(
888 $self->offset + 2, $self->engine->byte_size,
890 return unpack( $StP{$self->engine->byte_size}, $chain_loc );
898 my $chain_loc = $self->chain_loc;
900 $data .= $self->engine->storage->read_at(
901 $self->offset + 2 + $self->engine->byte_size + 1, $self->data_length,
904 last unless $chain_loc;
906 $self = $self->engine->_load_sector( $chain_loc );
912 package DBM::Deep::Engine::Sector::Null;
914 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
916 sub type { $_[0]{engine}->SIG_NULL }
917 sub data_length { 0 }
923 my $engine = $self->engine;
925 unless ( $self->offset ) {
926 my $leftover = $self->size - 3 - 1 * $engine->byte_size;
928 $self->{offset} = $engine->_request_sector( $self->size );
929 $engine->storage->print_at( $self->offset,
930 $self->type, # Sector type
931 pack( $StP{1}, 0 ), # Recycled counter
932 pack( $StP{$engine->byte_size}, 0 ), # Chain loc
933 pack( $StP{1}, $self->data_length ), # Data length
934 chr(0) x $leftover, # Zero-fill the rest
941 package DBM::Deep::Engine::Sector::Reference;
943 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
948 my $engine = $self->engine;
950 unless ( $self->offset ) {
951 my $classname = Scalar::Util::blessed( delete $self->{data} );
952 my $leftover = $self->size - 2 - 2 * $engine->byte_size;
954 my $class_offset = 0;
955 if ( defined $classname ) {
956 my $class_sector = DBM::Deep::Engine::Sector::Scalar->new({
957 engine => $self->engine,
960 $class_offset = $class_sector->offset;
963 $self->{offset} = $engine->_request_sector( $self->size );
964 $engine->storage->print_at( $self->offset,
965 $self->type, # Sector type
966 pack( $StP{1}, 0 ), # Recycled counter
967 pack( $StP{$engine->byte_size}, 0 ), # Index/BList loc
968 pack( $StP{$engine->byte_size}, $class_offset ), # Classname loc
969 chr(0) x $leftover, # Zero-fill the rest
975 $self->{type} = $engine->storage->read_at( $self->offset, 1 );
984 # Assume that the head is not allowed unless otherwise specified.
985 $args->{allow_head} = 0 unless exists $args->{allow_head};
987 # Assume we don't create a new blist location unless otherwise specified.
988 $args->{create} = 0 unless exists $args->{create};
990 my $blist = $self->get_bucket_list({
991 key_md5 => $args->{key_md5},
992 create => $args->{create},
994 return unless $blist && $blist->{found};
996 # At this point, $blist knows where the md5 is. What it -doesn't- know yet
997 # is whether or not this transaction has this key. That's part of the next
999 my $location = $blist->get_data_location_for({
1000 allow_head => $args->{allow_head},
1003 return $self->engine->_load_sector( $location );
1010 my $blist = $self->get_bucket_list({
1011 key_md5 => $args->{key_md5},
1013 }) or die "How did write_data fail (no blist)?!\n";
1015 # Handle any transactional bookkeeping.
1016 if ( $self->engine->trans_id ) {
1017 if ( ! $blist->{found} ) {
1018 $blist->mark_deleted({
1024 my @trans_ids = $self->engine->get_running_txn_ids;
1025 if ( $blist->{found} ) {
1027 my $old_value = $blist->get_data_for;
1028 foreach my $other_trans_id ( @trans_ids ) {
1029 next if $blist->get_data_location_for({
1030 trans_id => $other_trans_id,
1034 trans_id => $other_trans_id,
1035 key => $args->{key},
1036 key_md5 => $args->{key_md5},
1037 value => $old_value->clone,
1044 foreach my $other_trans_id ( @trans_ids ) {
1045 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1046 $blist->mark_deleted({
1047 trans_id => $other_trans_id,
1054 #XXX Is this safe to do transactionally?
1055 # Free the place we're about to write to.
1056 if ( $blist->get_data_location_for({ allow_head => 0 }) ) {
1057 $blist->get_data_for({ allow_head => 0 })->free;
1061 key => $args->{key},
1062 key_md5 => $args->{key_md5},
1063 value => $args->{value},
1071 # XXX What should happen if this fails?
1072 my $blist = $self->get_bucket_list({
1073 key_md5 => $args->{key_md5},
1074 }) or die "How did delete_key fail (no blist)?!\n";
1076 # Save the location so that we can free the data
1077 my $location = $blist->get_data_location_for({
1080 my $old_value = $location && $self->engine->_load_sector( $location );
1082 if ( $self->engine->trans_id == 0 ) {
1083 my @trans_ids = $self->engine->get_running_txn_ids;
1085 foreach my $other_trans_id ( @trans_ids ) {
1086 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1088 trans_id => $other_trans_id,
1089 key => $args->{key},
1090 key_md5 => $args->{key_md5},
1091 value => $old_value->clone,
1097 $blist->mark_deleted( $args );
1101 $data = $old_value->data;
1111 my $e = $self->engine;
1112 my $blist_loc = $e->storage->read_at( $self->offset + 2, $e->byte_size );
1113 return unpack( $StP{$e->byte_size}, $blist_loc );
1116 sub get_bucket_list {
1121 # XXX Add in check here for recycling?
1123 my $engine = $self->engine;
1125 my $blist_loc = $self->get_blist_loc;
1127 # There's no index or blist yet
1128 unless ( $blist_loc ) {
1129 return unless $args->{create};
1131 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1133 key_md5 => $args->{key_md5},
1136 $engine->storage->print_at( $self->offset + 2,
1137 pack( $StP{$engine->byte_size}, $blist->offset ),
1143 return DBM::Deep::Engine::Sector::BucketList->new({
1145 offset => $blist_loc,
1146 key_md5 => $args->{key_md5},
1153 my $class_offset = $self->engine->storage->read_at(
1154 $self->offset + 2 + 1 * $self->engine->byte_size, $self->engine->byte_size,
1156 $class_offset = unpack ( $StP{$self->engine->byte_size}, $class_offset );
1158 return unless $class_offset;
1160 return $self->engine->_load_sector( $class_offset )->data;
1166 my $new_obj = DBM::Deep->new({
1167 type => $self->type,
1168 base_offset => $self->offset,
1169 storage => $self->engine->storage,
1170 engine => $self->engine,
1173 if ( $self->engine->storage->{autobless} ) {
1174 my $classname = $self->get_classname;
1175 if ( defined $classname ) {
1176 bless $new_obj, $classname;
1183 package DBM::Deep::Engine::Sector::BucketList;
1185 our @ISA = qw( DBM::Deep::Engine::Sector );
1190 my $engine = $self->engine;
1192 unless ( $self->offset ) {
1193 my $leftover = $self->size - $self->base_size;
1195 $self->{offset} = $engine->_request_sector( $self->size );
1196 $engine->storage->print_at( $self->offset,
1197 $engine->SIG_BLIST, # Sector type
1198 pack( $StP{1}, 0 ), # Recycled counter
1199 chr(0) x $leftover, # Zero-fill the data
1203 if ( $self->{key_md5} ) {
1210 sub base_size { 1 + 1 } # Sig + recycled counter
1214 unless ( $self->{size} ) {
1215 my $e = $self->engine;
1216 $self->{size} = $self->base_size + $e->max_buckets * $self->bucket_size; # Base + numbuckets * bucketsize
1218 return $self->{size};
1223 unless ( $self->{bucket_size} ) {
1224 my $e = $self->engine;
1225 # Key + head (location) + transactions (location + staleness-counter)
1226 my $location_size = $e->byte_size + $e->num_txns * ( $e->byte_size + 4 );
1227 $self->{bucket_size} = $e->hash_size + $location_size;
1229 return $self->{bucket_size};
1234 unless ( exists $self->{found} ) {
1237 return $self->{found};
1243 $self->{found} = undef;
1246 # If we don't have an MD5, then what are we supposed to do?
1247 unless ( exists $self->{key_md5} ) {
1248 DBM::Deep->_throw_error( "Cannot find_md5 without a key_md5 set" );
1251 my $e = $self->engine;
1252 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
1253 my $potential = $e->storage->read_at(
1254 $self->offset + $self->base_size + $idx * $self->bucket_size, $e->hash_size,
1257 if ( $potential eq $e->blank_md5 ) {
1258 $self->{idx} = $idx;
1262 if ( $potential eq $self->{key_md5} ) {
1264 $self->{idx} = $idx;
1276 DBM::Deep->_throw_error( "write_md5: no key" ) unless exists $args->{key};
1277 DBM::Deep->_throw_error( "write_md5: no key_md5" ) unless exists $args->{key_md5};
1278 DBM::Deep->_throw_error( "write_md5: no value" ) unless exists $args->{value};
1280 my $engine = $self->engine;
1282 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
1284 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1285 $engine->add_entry( $args->{trans_id}, $spot );
1287 unless ($self->{found}) {
1288 my $key_sector = DBM::Deep::Engine::Sector::Scalar->new({
1290 data => $args->{key},
1293 $engine->storage->print_at( $spot,
1295 pack( $StP{$engine->byte_size}, $key_sector->offset ),
1300 + $engine->hash_size
1301 + $engine->byte_size
1302 + $args->{trans_id} * ( $engine->byte_size + 4 );
1304 $engine->storage->print_at( $loc,
1305 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
1306 pack( 'N', $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
1315 my $engine = $self->engine;
1317 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
1319 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1320 $engine->add_entry( $args->{trans_id}, $spot );
1323 + $engine->hash_size
1324 + $engine->byte_size
1325 + $args->{trans_id} * ( $engine->byte_size + 4 );
1327 $engine->storage->print_at( $loc,
1328 pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
1329 pack( 'N', $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
1337 my $engine = $self->engine;
1338 return undef unless $self->{found};
1340 # Save the location so that we can free the data
1341 my $location = $self->get_data_location_for({
1344 my $key_sector = $self->get_key_for;
1346 #XXX This isn't going to work right and you know it! This eradicates data
1347 # that we're not ready to eradicate just yet.
1348 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1349 $engine->storage->print_at( $spot,
1350 $engine->storage->read_at(
1351 $spot + $self->bucket_size,
1352 $self->bucket_size * ( $engine->num_txns - $self->{idx} - 1 ),
1354 chr(0) x $self->bucket_size,
1359 my $data_sector = $self->engine->_load_sector( $location );
1360 my $data = $data_sector->data;
1366 sub get_data_location_for {
1371 $args->{allow_head} = 0 unless exists $args->{allow_head};
1372 $args->{trans_id} = $self->engine->trans_id unless exists $args->{trans_id};
1373 $args->{idx} = $self->{idx} unless exists $args->{idx};
1375 my $e = $self->engine;
1377 my $spot = $self->offset + $self->base_size
1378 + $args->{idx} * $self->bucket_size
1381 + $args->{trans_id} * ( $e->byte_size + 4 );
1383 my $buffer = $e->storage->read_at(
1387 my ($loc, $staleness) = unpack( $StP{$e->byte_size} . ' N', $buffer );
1389 # We have found an entry that is old, so get rid of it
1390 if ( $staleness != (my $s = $e->get_txn_staleness_counter( $args->{trans_id} ) ) ) {
1391 $e->storage->print_at(
1393 pack( $StP{$e->byte_size} . ' N', (0) x 2 ),
1398 # If we're in a transaction and we never wrote to this location, try the
1400 if ( $args->{trans_id} && !$loc && $args->{allow_head} ) {
1401 return $self->get_data_location_for({
1404 idx => $args->{idx},
1407 return $loc <= 1 ? 0 : $loc;
1415 return unless $self->{found};
1416 my $location = $self->get_data_location_for({
1417 allow_head => $args->{allow_head},
1419 return $self->engine->_load_sector( $location );
1425 $idx = $self->{idx} unless defined $idx;
1427 my $location = $self->engine->storage->read_at(
1428 $self->offset + $self->base_size + $idx * $self->bucket_size + $self->engine->hash_size,
1429 $self->engine->byte_size,
1431 $location = unpack( $StP{$self->engine->byte_size}, $location );
1432 return unless $location;
1433 return $self->engine->_load_sector( $location );
1439 package DBM::Deep::Engine::Sector::BucketList;
1441 our @ISA = qw( DBM::Deep::Engine::Sector );
1446 my $engine = $self->engine;
1448 unless ( $self->offset ) {
1449 my $leftover = $self->size - $self->base_size;
1451 $self->{offset} = $engine->_request_sector( $self->size );
1452 $engine->storage->print_at( $self->offset,
1453 $engine->SIG_BLIST, # Sector type
1454 pack( $StP{1}, 0 ), # Recycled counter
1455 chr(0) x $leftover, # Zero-fill the data
1459 if ( $self->{key_md5} ) {
1466 sub base_size { 1 + 1 } # Sig + recycled counter
1470 unless ( $self->{size} ) {
1471 my $e = $self->engine;
1472 $self->{size} = $self->base_size + $e->max_buckets * $self->bucket_size; # Base + numbuckets * bucketsize
1474 return $self->{size};
1479 unless ( $self->{bucket_size} ) {
1480 my $e = $self->engine;
1481 # Key + head (location) + transactions (location + staleness-counter)
1482 my $location_size = $e->byte_size + $e->num_txns * ( $e->byte_size + 4 );
1483 $self->{bucket_size} = $e->hash_size + $location_size;
1485 return $self->{bucket_size};