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' }
30 sub STALE_SIZE () { 1 }
32 ################################################################################
34 # Please refer to the pack() documentation for further information
36 1 => 'C', # Unsigned char value (no order specified, presumably ASCII)
37 2 => 'n', # Unsigned short in "network" (big-endian) order
38 4 => 'N', # Unsigned long in "network" (big-endian) order
39 8 => 'Q', # Usigned quad (no order specified, presumably machine-dependent)
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 )
111 if ( $sector->staleness != $obj->_staleness ) {
115 my $key_md5 = $self->_apply_digest( $key );
117 my $value_sector = $sector->get_data_for({
122 unless ( $value_sector ) {
123 $value_sector = DBM::Deep::Engine::Sector::Null->new({
128 $sector->write_data({
131 value => $value_sector,
135 return $value_sector->data;
142 # This will be a Reference sector
143 my $sector = $self->_load_sector( $obj->_base_offset )
144 or die "How did get_classname fail (no sector for '$obj')?!\n";
146 if ( $sector->staleness != $obj->_staleness ) {
150 return $sector->get_classname;
155 my ($obj, $key) = @_;
157 # This will be a Reference sector
158 my $sector = $self->_load_sector( $obj->_base_offset )
161 if ( $sector->staleness != $obj->_staleness ) {
165 my $data = $sector->get_data_for({
166 key_md5 => $self->_apply_digest( $key ),
170 # exists() returns 1 or '' for true/false.
171 return $data ? 1 : '';
176 my ($obj, $key) = @_;
178 my $sector = $self->_load_sector( $obj->_base_offset )
181 if ( $sector->staleness != $obj->_staleness ) {
185 return $sector->delete_key({
186 key_md5 => $self->_apply_digest( $key ),
193 my ($obj, $key, $value) = @_;
195 my $r = Scalar::Util::reftype( $value ) || '';
198 last if $r eq 'HASH';
199 last if $r eq 'ARRAY';
201 DBM::Deep->_throw_error(
202 "Storage of references of type '$r' is not supported."
207 if ( !defined $value ) {
208 $class = 'DBM::Deep::Engine::Sector::Null';
210 elsif ( $r eq 'ARRAY' || $r eq 'HASH' ) {
211 if ( $r eq 'ARRAY' && tied(@$value) ) {
212 DBM::Deep->_throw_error( "Cannot store something that is tied." );
214 if ( $r eq 'HASH' && tied(%$value) ) {
215 DBM::Deep->_throw_error( "Cannot store something that is tied." );
217 $class = 'DBM::Deep::Engine::Sector::Reference';
218 $type = substr( $r, 0, 1 );
221 $class = 'DBM::Deep::Engine::Sector::Scalar';
224 # This will be a Reference sector
225 my $sector = $self->_load_sector( $obj->_base_offset )
226 or die "Cannot write to a deleted spot in DBM::Deep.\n";
228 if ( $sector->staleness != $obj->_staleness ) {
229 die "Cannot write to a deleted spot in DBM::Deep.\n";
232 # Create this after loading the reference sector in case something bad happens.
233 # This way, we won't allocate value sector(s) needlessly.
234 my $value_sector = $class->new({
240 $sector->write_data({
242 key_md5 => $self->_apply_digest( $key ),
243 value => $value_sector,
246 # This code is to make sure we write all the values in the $value to the disk
247 # and to make sure all changes to $value after the assignment are reflected
248 # on disk. This may be counter-intuitive at first, but it is correct dwimmery.
249 # NOTE - simply tying $value won't perform a STORE on each value. Hence, the
250 # copy to a temp value.
251 if ( $r eq 'ARRAY' ) {
253 tie @$value, 'DBM::Deep', {
254 base_offset => $value_sector->offset,
255 staleness => $value_sector->staleness,
256 storage => $self->storage,
260 bless $value, 'DBM::Deep::Array' unless Scalar::Util::blessed( $value );
262 elsif ( $r eq 'HASH' ) {
264 tie %$value, 'DBM::Deep', {
265 base_offset => $value_sector->offset,
266 staleness => $value_sector->staleness,
267 storage => $self->storage,
272 bless $value, 'DBM::Deep::Hash' unless Scalar::Util::blessed( $value );
278 # XXX Add staleness here
281 my ($obj, $prev_key) = @_;
283 # XXX Need to add logic about resetting the iterator if any key in the reference has changed
284 unless ( $prev_key ) {
285 $obj->{iterator} = DBM::Deep::Engine::Iterator->new({
286 base_offset => $obj->_base_offset,
291 return $obj->{iterator}->get_next_key( $obj );
294 ################################################################################
300 # We're opening the file.
301 unless ( $obj->_base_offset ) {
302 my $bytes_read = $self->_read_file_header;
304 # Creating a new file
305 unless ( $bytes_read ) {
306 $self->_write_file_header;
308 # 1) Create Array/Hash entry
309 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
313 $obj->{base_offset} = $initial_reference->offset;
314 $obj->{staleness} = $initial_reference->staleness;
316 $self->storage->flush;
318 # Reading from an existing file
320 $obj->{base_offset} = $bytes_read;
321 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
323 offset => $obj->_base_offset,
325 unless ( $initial_reference ) {
326 DBM::Deep->_throw_error("Corrupted file, no master index record");
329 unless ($obj->_type eq $initial_reference->type) {
330 DBM::Deep->_throw_error("File type mismatch");
333 $obj->{staleness} = $initial_reference->staleness;
344 if ( $self->trans_id ) {
345 DBM::Deep->_throw_error( "Cannot begin_work within a transaction" );
348 my @slots = $self->read_txn_slots;
349 for my $i ( 1 .. @slots ) {
352 $self->set_trans_id( $i );
355 $self->write_txn_slots( @slots );
357 if ( !$self->trans_id ) {
358 DBM::Deep->_throw_error( "Cannot begin_work - no available transactions" );
368 if ( !$self->trans_id ) {
369 DBM::Deep->_throw_error( "Cannot rollback without a transaction" );
372 # Each entry is the file location for a bucket that has a modification for
373 # this transaction. The entries need to be expunged.
374 foreach my $entry (@{ $self->get_entries } ) {
375 # Remove the entry here
376 my $read_loc = $entry
379 + $self->trans_id * ( $self->byte_size + 4 );
381 my $data_loc = $self->storage->read_at( $read_loc, $self->byte_size );
382 $data_loc = unpack( $StP{$self->byte_size}, $data_loc );
383 $self->storage->print_at( $read_loc, pack( $StP{$self->byte_size}, 0 ) );
385 if ( $data_loc > 1 ) {
386 $self->_load_sector( $data_loc )->free;
390 $self->clear_entries;
392 my @slots = $self->read_txn_slots;
393 $slots[$self->trans_id] = 0;
394 $self->write_txn_slots( @slots );
395 $self->inc_txn_staleness_counter( $self->trans_id );
396 $self->set_trans_id( 0 );
405 if ( !$self->trans_id ) {
406 DBM::Deep->_throw_error( "Cannot commit without a transaction" );
409 foreach my $entry (@{ $self->get_entries } ) {
410 # Overwrite the entry in head with the entry in trans_id
415 my $head_loc = $self->storage->read_at( $base, $self->byte_size );
416 $head_loc = unpack( $StP{$self->byte_size}, $head_loc );
417 my $trans_loc = $self->storage->read_at(
418 $base + $self->trans_id * ( $self->byte_size + 4 ), $self->byte_size,
421 $self->storage->print_at( $base, $trans_loc );
422 $self->storage->print_at(
423 $base + $self->trans_id * ( $self->byte_size + 4 ),
424 pack( $StP{$self->byte_size} . ' N', (0) x 2 ),
427 if ( $head_loc > 1 ) {
428 $self->_load_sector( $head_loc )->free;
432 $self->clear_entries;
434 my @slots = $self->read_txn_slots;
435 $slots[$self->trans_id] = 0;
436 $self->write_txn_slots( @slots );
437 $self->inc_txn_staleness_counter( $self->trans_id );
438 $self->set_trans_id( 0 );
445 return split '', unpack( 'b32',
446 $self->storage->read_at(
452 sub write_txn_slots {
454 $self->storage->print_at( $self->trans_loc,
455 pack( 'b32', join('', @_) ),
459 sub get_running_txn_ids {
461 my @transactions = $self->read_txn_slots;
462 my @trans_ids = grep { $transactions[$_] } 0 .. $#transactions;
465 sub get_txn_staleness_counter {
469 # Hardcode staleness of 0 for the HEAD
470 return 0 unless $trans_id;
473 $self->storage->read_at(
474 $self->trans_loc + 4 * $trans_id,
481 sub inc_txn_staleness_counter {
485 # Hardcode staleness of 0 for the HEAD
486 return unless $trans_id;
488 $self->storage->print_at(
489 $self->trans_loc + 4 * $trans_id,
490 pack( 'N', $self->get_txn_staleness_counter( $trans_id ) + 1 ),
496 return [ keys %{ $self->{entries}{$self->trans_id} ||= {} } ];
501 my ($trans_id, $loc) = @_;
503 $self->{entries}{$trans_id} ||= {};
504 $self->{entries}{$trans_id}{$loc} = undef;
509 delete $self->{entries}{$self->trans_id};
512 ################################################################################
515 my $header_fixed = length( SIG_FILE ) + 1 + 4 + 4;
517 sub _write_file_header {
520 my $header_var = 1 + 1 + 4 + 4 * $self->num_txns + 3 * $self->byte_size;
522 my $loc = $self->storage->request_space( $header_fixed + $header_var );
524 $self->storage->print_at( $loc,
527 pack('N', 1), # header version - at this point, we're at 9 bytes
528 pack('N', $header_var), # header size
529 # --- Above is $header_fixed. Below is $header_var
530 pack('C', $self->byte_size),
531 pack('C', $self->max_buckets),
532 pack('N', 0 ), # Transaction activeness bitfield
533 pack('N' . $self->num_txns, 0 x $self->num_txns ), # Transaction staleness counters
534 pack($StP{$self->byte_size}, 0), # Start of free chain (blist size)
535 pack($StP{$self->byte_size}, 0), # Start of free chain (data size)
536 pack($StP{$self->byte_size}, 0), # Start of free chain (index size)
539 $self->set_trans_loc( $header_fixed + 2 );
540 $self->set_chains_loc( $header_fixed + 2 + 4 + 4 * $self->num_txns );
545 sub _read_file_header {
548 my $buffer = $self->storage->read_at( 0, $header_fixed );
549 return unless length($buffer);
551 my ($file_signature, $sig_header, $header_version, $size) = unpack(
555 unless ( $file_signature eq SIG_FILE ) {
556 $self->storage->close;
557 DBM::Deep->_throw_error( "Signature not found -- file is not a Deep DB" );
560 unless ( $sig_header eq SIG_HEADER ) {
561 $self->storage->close;
562 DBM::Deep->_throw_error( "Old file version found." );
565 my $buffer2 = $self->storage->read_at( undef, $size );
566 my @values = unpack( 'C C', $buffer2 );
568 $self->set_trans_loc( $header_fixed + 2 );
569 $self->set_chains_loc( $header_fixed + 2 + 4 + 4 * $self->num_txns );
571 if ( @values < 2 || grep { !defined } @values ) {
572 $self->storage->close;
573 DBM::Deep->_throw_error("Corrupted file - bad header");
576 #XXX Add warnings if values weren't set right
577 @{$self}{qw(byte_size max_buckets)} = @values;
579 my $header_var = 1 + 1 + 4 + 4 * $self->num_txns + 3 * $self->byte_size;
580 unless ( $size eq $header_var ) {
581 $self->storage->close;
582 DBM::Deep->_throw_error( "Unexpected size found ($size <-> $header_var)." );
585 return length($buffer) + length($buffer2);
593 my $type = $self->storage->read_at( $offset, 1 );
594 return if $type eq chr(0);
596 if ( $type eq $self->SIG_ARRAY || $type eq $self->SIG_HASH ) {
597 return DBM::Deep::Engine::Sector::Reference->new({
603 # XXX Don't we need key_md5 here?
604 elsif ( $type eq $self->SIG_BLIST ) {
605 return DBM::Deep::Engine::Sector::BucketList->new({
611 elsif ( $type eq $self->SIG_INDEX ) {
612 return DBM::Deep::Engine::Sector::Index->new({
618 elsif ( $type eq $self->SIG_NULL ) {
619 return DBM::Deep::Engine::Sector::Null->new({
625 elsif ( $type eq $self->SIG_DATA ) {
626 return DBM::Deep::Engine::Sector::Scalar->new({
632 # This was deleted from under us, so just return and let the caller figure it out.
633 elsif ( $type eq $self->SIG_FREE ) {
637 die "'$offset': Don't know what to do with type '$type'\n";
642 return $self->{digest}->(@_);
645 sub _add_free_blist_sector { shift->_add_free_sector( 0, @_ ) }
646 sub _add_free_data_sector { shift->_add_free_sector( 1, @_ ) }
647 sub _add_free_index_sector { shift->_add_free_sector( 2, @_ ) }
649 sub _add_free_sector {
651 my ($multiple, $offset, $size) = @_;
653 my $chains_offset = $multiple * $self->byte_size;
655 my $storage = $self->storage;
657 # Increment staleness.
658 # XXX Can this increment+modulo be done by "&= 0x1" ?
659 my $staleness = unpack( $StP{STALE_SIZE()}, $storage->read_at( $offset + SIG_SIZE, STALE_SIZE ) );
660 $staleness = ($staleness + 1 ) % ( 2 ** ( 8 * STALE_SIZE ) );
661 $storage->print_at( $offset + SIG_SIZE, pack( $StP{STALE_SIZE()}, $staleness ) );
663 my $old_head = $storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
665 $storage->print_at( $self->chains_loc + $chains_offset,
666 pack( $StP{$self->byte_size}, $offset ),
669 # Record the old head in the new sector after the signature and staleness counter
670 $storage->print_at( $offset + SIG_SIZE + STALE_SIZE, $old_head );
673 sub _request_blist_sector { shift->_request_sector( 0, @_ ) }
674 sub _request_data_sector { shift->_request_sector( 1, @_ ) }
675 sub _request_index_sector { shift->_request_sector( 2, @_ ) }
677 sub _request_sector {
679 my ($multiple, $size) = @_;
681 my $chains_offset = $multiple * $self->byte_size;
683 my $old_head = $self->storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
684 my $loc = unpack( $StP{$self->byte_size}, $old_head );
686 # We don't have any free sectors of the right size, so allocate a new one.
688 my $offset = $self->storage->request_space( $size );
690 # Zero out the new sector. This also guarantees correct increases
692 $self->storage->print_at( $offset, chr(0) x $size );
697 # Read the new head after the signature and the staleness counter
698 my $new_head = $self->storage->read_at( $loc + SIG_SIZE + STALE_SIZE, $self->byte_size );
699 $self->storage->print_at( $self->chains_loc + $chains_offset, $new_head );
704 ################################################################################
706 sub storage { $_[0]{storage} }
707 sub byte_size { $_[0]{byte_size} }
708 sub hash_size { $_[0]{hash_size} }
709 sub num_txns { $_[0]{num_txns} }
710 sub max_buckets { $_[0]{max_buckets} }
711 sub blank_md5 { chr(0) x $_[0]->hash_size }
713 sub trans_id { $_[0]{trans_id} }
714 sub set_trans_id { $_[0]{trans_id} = $_[1] }
716 sub trans_loc { $_[0]{trans_loc} }
717 sub set_trans_loc { $_[0]{trans_loc} = $_[1] }
719 sub chains_loc { $_[0]{chains_loc} }
720 sub set_chains_loc { $_[0]{chains_loc} = $_[1] }
722 ################################################################################
724 package DBM::Deep::Engine::Iterator;
732 engine => $args->{engine},
733 base_offset => $args->{base_offset},
736 Scalar::Util::weaken( $self->{engine} );
743 $self->{breadcrumbs} = [];
750 my $crumbs = $self->{breadcrumbs};
752 unless ( @$crumbs ) {
753 # This will be a Reference sector
754 my $sector = $self->{engine}->_load_sector( $self->{base_offset} )
755 # or die "Iterator: How did this fail (no ref sector for '$self->{base_offset}')?!\n";
756 # If no sector is found, thist must have been deleted from under us.
759 if ( $sector->staleness != $obj->_staleness ) {
763 push @$crumbs, [ $sector->get_blist_loc, 0 ];
768 my ($offset, $idx) = @{ $crumbs->[-1] };
774 if ( $idx >= $self->{engine}->max_buckets ) {
779 my $sector = $self->{engine}->_load_sector( $offset )
780 or die "Iterator: How did this fail (no blist sector for '$offset')?!\n";
782 #XXX Think this through!
783 my $loc = $sector->get_data_location_for({
792 my $key_sector = $sector->get_key_for( $idx );
793 unless ( $key_sector ) {
799 $key = $key_sector->data;
806 package DBM::Deep::Engine::Sector;
809 my $self = bless $_[1], $_[0];
810 Scalar::Util::weaken( $self->{engine} );
815 sub clone { die "Must be implemented in the child class" }
817 sub engine { $_[0]{engine} }
818 sub offset { $_[0]{offset} }
819 sub type { $_[0]{type} }
823 return $self->engine->SIG_SIZE + $self->engine->STALE_SIZE;
829 my $e = $self->engine;
831 $e->storage->print_at( $self->offset, $e->SIG_FREE );
832 # Skip staleness counter
833 $e->storage->print_at( $self->offset + $self->base_size,
834 chr(0) x ($self->size - $self->base_size),
837 my $free_meth = $self->free_meth;
838 $e->$free_meth( $self->offset, $self->size );
843 package DBM::Deep::Engine::Sector::Data;
845 our @ISA = qw( DBM::Deep::Engine::Sector );
848 sub size { return 256 }
849 sub free_meth { return '_add_free_data_sector' }
853 return ref($self)->new({
854 engine => $self->engine,
860 package DBM::Deep::Engine::Sector::Scalar;
862 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
867 my $chain_loc = $self->chain_loc;
869 $self->SUPER::free();
872 $self->engine->_load_sector( $chain_loc )->free;
878 sub type { $_[0]{engine}->SIG_DATA }
882 my $engine = $self->engine;
884 unless ( $self->offset ) {
885 my $data_section = $self->size - $self->base_size - 1 * $engine->byte_size - 1;
887 $self->{offset} = $engine->_request_data_sector( $self->size );
889 my $data = delete $self->{data};
890 my $dlen = length $data;
892 my $curr_offset = $self->offset;
893 while ( $continue ) {
897 my ($leftover, $this_len, $chunk);
898 if ( $dlen > $data_section ) {
900 $this_len = $data_section;
901 $chunk = substr( $data, 0, $this_len );
903 $dlen -= $data_section;
904 $next_offset = $engine->_request_data_sector( $self->size );
905 $data = substr( $data, $this_len );
908 $leftover = $data_section - $dlen;
915 $engine->storage->print_at( $curr_offset, $self->type ); # Sector type
917 $engine->storage->print_at( $curr_offset + $self->base_size,
918 pack( $StP{$engine->byte_size}, $next_offset ), # Chain loc
919 pack( $StP{1}, $this_len ), # Data length
920 $chunk, # Data to be stored in this sector
921 chr(0) x $leftover, # Zero-fill the rest
924 $curr_offset = $next_offset;
934 my $buffer = $self->engine->storage->read_at(
935 $self->offset + $self->base_size + $self->engine->byte_size, 1
938 return unpack( $StP{1}, $buffer );
943 my $chain_loc = $self->engine->storage->read_at(
944 $self->offset + $self->base_size, $self->engine->byte_size,
946 return unpack( $StP{$self->engine->byte_size}, $chain_loc );
954 my $chain_loc = $self->chain_loc;
956 $data .= $self->engine->storage->read_at(
957 $self->offset + $self->base_size + $self->engine->byte_size + 1, $self->data_length,
960 last unless $chain_loc;
962 $self = $self->engine->_load_sector( $chain_loc );
968 package DBM::Deep::Engine::Sector::Null;
970 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
972 sub type { $_[0]{engine}->SIG_NULL }
973 sub data_length { 0 }
979 my $engine = $self->engine;
981 unless ( $self->offset ) {
982 my $leftover = $self->size - $self->base_size - 1 * $engine->byte_size - 1;
984 $self->{offset} = $engine->_request_data_sector( $self->size );
985 $engine->storage->print_at( $self->offset, $self->type ); # Sector type
986 # Skip staleness counter
987 $engine->storage->print_at( $self->offset + $self->base_size,
988 pack( $StP{$engine->byte_size}, 0 ), # Chain loc
989 pack( $StP{1}, $self->data_length ), # Data length
990 chr(0) x $leftover, # Zero-fill the rest
997 package DBM::Deep::Engine::Sector::Reference;
999 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1004 my $e = $self->engine;
1006 unless ( $self->offset ) {
1007 my $classname = Scalar::Util::blessed( delete $self->{data} );
1008 my $leftover = $self->size - $self->base_size - 2 * $e->byte_size;
1010 my $class_offset = 0;
1011 if ( defined $classname ) {
1012 my $class_sector = DBM::Deep::Engine::Sector::Scalar->new({
1016 $class_offset = $class_sector->offset;
1019 $self->{offset} = $e->_request_data_sector( $self->size );
1020 $e->storage->print_at( $self->offset, $self->type ); # Sector type
1021 # Skip staleness counter
1022 $e->storage->print_at( $self->offset + $self->base_size,
1023 pack( $StP{$e->byte_size}, 0 ), # Index/BList loc
1024 pack( $StP{$e->byte_size}, $class_offset ), # Classname loc
1025 chr(0) x $leftover, # Zero-fill the rest
1029 $self->{type} = $e->storage->read_at( $self->offset, 1 );
1032 $self->{staleness} = unpack(
1033 $StP{$e->STALE_SIZE},
1034 $e->storage->read_at( $self->offset + $e->SIG_SIZE, $e->STALE_SIZE ),
1043 my $blist_loc = $self->get_blist_loc;
1044 $self->engine->_load_sector( $blist_loc )->free if $blist_loc;
1046 my $class_loc = $self->get_class_offset;
1047 $self->engine->_load_sector( $class_loc )->free if $class_loc;
1049 $self->SUPER::free();
1052 sub staleness { $_[0]{staleness} }
1058 # Assume that the head is not allowed unless otherwise specified.
1059 $args->{allow_head} = 0 unless exists $args->{allow_head};
1061 # Assume we don't create a new blist location unless otherwise specified.
1062 $args->{create} = 0 unless exists $args->{create};
1064 my $blist = $self->get_bucket_list({
1065 key_md5 => $args->{key_md5},
1066 create => $args->{create},
1068 return unless $blist && $blist->{found};
1070 # At this point, $blist knows where the md5 is. What it -doesn't- know yet
1071 # is whether or not this transaction has this key. That's part of the next
1073 my $location = $blist->get_data_location_for({
1074 allow_head => $args->{allow_head},
1077 return $self->engine->_load_sector( $location );
1084 my $blist = $self->get_bucket_list({
1085 key_md5 => $args->{key_md5},
1087 }) or die "How did write_data fail (no blist)?!\n";
1089 # Handle any transactional bookkeeping.
1090 if ( $self->engine->trans_id ) {
1091 if ( ! $blist->has_md5 ) {
1092 $blist->mark_deleted({
1098 my @trans_ids = $self->engine->get_running_txn_ids;
1099 if ( $blist->has_md5 ) {
1101 my $old_value = $blist->get_data_for;
1102 foreach my $other_trans_id ( @trans_ids ) {
1103 next if $blist->get_data_location_for({
1104 trans_id => $other_trans_id,
1108 trans_id => $other_trans_id,
1109 key => $args->{key},
1110 key_md5 => $args->{key_md5},
1111 value => $old_value->clone,
1118 foreach my $other_trans_id ( @trans_ids ) {
1119 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1120 $blist->mark_deleted({
1121 trans_id => $other_trans_id,
1128 #XXX Is this safe to do transactionally?
1129 # Free the place we're about to write to.
1130 if ( $blist->get_data_location_for({ allow_head => 0 }) ) {
1131 $blist->get_data_for({ allow_head => 0 })->free;
1135 key => $args->{key},
1136 key_md5 => $args->{key_md5},
1137 value => $args->{value},
1145 # XXX What should happen if this fails?
1146 my $blist = $self->get_bucket_list({
1147 key_md5 => $args->{key_md5},
1148 }) or die "How did delete_key fail (no blist)?!\n";
1150 # Save the location so that we can free the data
1151 my $location = $blist->get_data_location_for({
1154 my $old_value = $location && $self->engine->_load_sector( $location );
1156 if ( $self->engine->trans_id == 0 ) {
1157 my @trans_ids = $self->engine->get_running_txn_ids;
1159 foreach my $other_trans_id ( @trans_ids ) {
1160 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1162 trans_id => $other_trans_id,
1163 key => $args->{key},
1164 key_md5 => $args->{key_md5},
1165 value => $old_value->clone,
1171 $blist->mark_deleted( $args );
1175 $data = $old_value->data;
1185 my $e = $self->engine;
1186 my $blist_loc = $e->storage->read_at( $self->offset + $self->base_size, $e->byte_size );
1187 return unpack( $StP{$e->byte_size}, $blist_loc );
1190 sub get_bucket_list {
1195 # XXX Add in check here for recycling?
1197 my $engine = $self->engine;
1199 my $blist_loc = $self->get_blist_loc;
1201 # There's no index or blist yet
1202 unless ( $blist_loc ) {
1203 return unless $args->{create};
1205 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1207 key_md5 => $args->{key_md5},
1210 $engine->storage->print_at( $self->offset + $self->base_size,
1211 pack( $StP{$engine->byte_size}, $blist->offset ),
1217 # Add searching here through the index layers, if any
1218 my $sector = $engine->_load_sector( $blist_loc )
1219 or die "Cannot read sector at $blist_loc in get_bucket_list()";
1221 my $last_sector = undef;
1222 while ( $sector->isa( 'DBM::Deep::Engine::Sector::Index' ) ) {
1223 $blist_loc = $sector->location_for( ord( substr( $args->{key_md5}, $i++, 1 ) ) );
1224 $last_sector = $sector;
1225 $sector = $engine->_load_sector( $blist_loc )
1226 or die "Cannot read sector at $blist_loc in get_bucket_list()";
1229 $sector->find_md5( $args->{key_md5} );
1231 # See whether or not we need to reindex the bucketlist
1232 if ( !$sector->has_md5 && $args->{create} ) {
1238 sub get_class_offset {
1241 my $e = $self->engine;
1243 $StP{$e->byte_size},
1244 $e->storage->read_at(
1245 $self->offset + $self->base_size + 1 * $e->byte_size, $e->byte_size,
1253 my $class_offset = $self->get_class_offset;
1255 return unless $class_offset;
1257 return $self->engine->_load_sector( $class_offset )->data;
1263 my $new_obj = DBM::Deep->new({
1264 type => $self->type,
1265 base_offset => $self->offset,
1266 staleness => $self->staleness,
1267 storage => $self->engine->storage,
1268 engine => $self->engine,
1271 if ( $self->engine->storage->{autobless} ) {
1272 my $classname = $self->get_classname;
1273 if ( defined $classname ) {
1274 bless $new_obj, $classname;
1281 package DBM::Deep::Engine::Sector::BucketList;
1283 our @ISA = qw( DBM::Deep::Engine::Sector );
1288 my $engine = $self->engine;
1290 unless ( $self->offset ) {
1291 my $leftover = $self->size - $self->base_size;
1293 $self->{offset} = $engine->_request_blist_sector( $self->size );
1294 $engine->storage->print_at( $self->offset, $engine->SIG_BLIST ); # Sector type
1295 # Skip staleness counter
1296 $engine->storage->print_at( $self->offset + $self->base_size,
1297 chr(0) x $leftover, # Zero-fill the data
1301 if ( $self->{key_md5} ) {
1310 unless ( $self->{size} ) {
1311 my $e = $self->engine;
1312 # Base + numbuckets * bucketsize
1313 $self->{size} = $self->base_size + $e->max_buckets * $self->bucket_size;
1315 return $self->{size};
1318 sub free_meth { return '_add_free_blist_sector' }
1322 unless ( $self->{bucket_size} ) {
1323 my $e = $self->engine;
1324 # Key + head (location) + transactions (location + staleness-counter)
1325 my $location_size = $e->byte_size + $e->num_txns * ( $e->byte_size + 4 );
1326 $self->{bucket_size} = $e->hash_size + $location_size;
1328 return $self->{bucket_size};
1333 unless ( exists $self->{found} ) {
1336 return $self->{found};
1342 $self->{found} = undef;
1346 $self->{key_md5} = shift;
1349 # If we don't have an MD5, then what are we supposed to do?
1350 unless ( exists $self->{key_md5} ) {
1351 DBM::Deep->_throw_error( "Cannot find_md5 without a key_md5 set" );
1354 my $e = $self->engine;
1355 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
1356 my $potential = $e->storage->read_at(
1357 $self->offset + $self->base_size + $idx * $self->bucket_size, $e->hash_size,
1360 if ( $potential eq $e->blank_md5 ) {
1361 $self->{idx} = $idx;
1365 if ( $potential eq $self->{key_md5} ) {
1367 $self->{idx} = $idx;
1379 DBM::Deep->_throw_error( "write_md5: no key" ) unless exists $args->{key};
1380 DBM::Deep->_throw_error( "write_md5: no key_md5" ) unless exists $args->{key_md5};
1381 DBM::Deep->_throw_error( "write_md5: no value" ) unless exists $args->{value};
1383 my $engine = $self->engine;
1385 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
1387 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1388 $engine->add_entry( $args->{trans_id}, $spot );
1390 unless ($self->{found}) {
1391 my $key_sector = DBM::Deep::Engine::Sector::Scalar->new({
1393 data => $args->{key},
1396 $engine->storage->print_at( $spot,
1398 pack( $StP{$engine->byte_size}, $key_sector->offset ),
1403 + $engine->hash_size
1404 + $engine->byte_size
1405 + $args->{trans_id} * ( $engine->byte_size + 4 );
1407 $engine->storage->print_at( $loc,
1408 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
1409 pack( 'N', $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
1418 my $engine = $self->engine;
1420 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
1422 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1423 $engine->add_entry( $args->{trans_id}, $spot );
1426 + $engine->hash_size
1427 + $engine->byte_size
1428 + $args->{trans_id} * ( $engine->byte_size + 4 );
1430 $engine->storage->print_at( $loc,
1431 pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
1432 pack( 'N', $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
1440 my $engine = $self->engine;
1441 return undef unless $self->{found};
1443 # Save the location so that we can free the data
1444 my $location = $self->get_data_location_for({
1447 my $key_sector = $self->get_key_for;
1449 #XXX This isn't going to work right and you know it! This eradicates data
1450 # that we're not ready to eradicate just yet.
1451 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1452 $engine->storage->print_at( $spot,
1453 $engine->storage->read_at(
1454 $spot + $self->bucket_size,
1455 $self->bucket_size * ( $engine->num_txns - $self->{idx} - 1 ),
1457 chr(0) x $self->bucket_size,
1462 my $data_sector = $self->engine->_load_sector( $location );
1463 my $data = $data_sector->data;
1469 sub get_data_location_for {
1474 $args->{allow_head} = 0 unless exists $args->{allow_head};
1475 $args->{trans_id} = $self->engine->trans_id unless exists $args->{trans_id};
1476 $args->{idx} = $self->{idx} unless exists $args->{idx};
1478 my $e = $self->engine;
1480 my $spot = $self->offset + $self->base_size
1481 + $args->{idx} * $self->bucket_size
1484 + $args->{trans_id} * ( $e->byte_size + 4 );
1486 my $buffer = $e->storage->read_at(
1490 my ($loc, $staleness) = unpack( $StP{$e->byte_size} . ' N', $buffer );
1492 # We have found an entry that is old, so get rid of it
1493 if ( $staleness != (my $s = $e->get_txn_staleness_counter( $args->{trans_id} ) ) ) {
1494 $e->storage->print_at(
1496 pack( $StP{$e->byte_size} . ' N', (0) x 2 ),
1501 # If we're in a transaction and we never wrote to this location, try the
1503 if ( $args->{trans_id} && !$loc && $args->{allow_head} ) {
1504 return $self->get_data_location_for({
1507 idx => $args->{idx},
1510 return $loc <= 1 ? 0 : $loc;
1518 return unless $self->{found};
1519 my $location = $self->get_data_location_for({
1520 allow_head => $args->{allow_head},
1522 return $self->engine->_load_sector( $location );
1528 $idx = $self->{idx} unless defined $idx;
1530 my $location = $self->engine->storage->read_at(
1531 $self->offset + $self->base_size + $idx * $self->bucket_size + $self->engine->hash_size,
1532 $self->engine->byte_size,
1534 $location = unpack( $StP{$self->engine->byte_size}, $location );
1535 return unless $location;
1536 return $self->engine->_load_sector( $location );
1539 package DBM::Deep::Engine::Sector::Index;
1541 our @ISA = qw( DBM::Deep::Engine::Sector );
1546 my $engine = $self->engine;
1548 unless ( $self->offset ) {
1549 my $leftover = $self->size - $self->base_size;
1551 $self->{offset} = $engine->_request_index_sector( $self->size );
1552 $engine->storage->print_at( $self->offset, $engine->SIG_BLIST ); # Sector type
1553 # Skip staleness counter
1554 $engine->storage->print_at( $self->offset + $self->base_size,
1555 chr(0) x $leftover, # Zero-fill the rest
1564 unless ( $self->{size} ) {
1565 my $e = $self->engine;
1566 $self->{size} = $self->base_size + $e->byte_size * $e->hash_chars;
1568 return $self->{size};
1571 sub free_meth { return '_add_free_index_sector' }
1575 my $e = $self->engine;
1577 for my $i ( 0 .. $e->hash_chars - 1 ) {
1578 my $l = $self->location_for( $i ) or next;
1579 $e->_load_sector( $l )->free;
1582 $self->SUPER::free();
1589 my $e = $self->engine;
1592 $StP{$e->byte_size},
1593 $e->storage->read_at(
1594 $self->offset + $self->base_size + $idx * $self->byte_size,