1 package DBM::Deep::Engine;
8 our $VERSION = q(1.0000);
13 # * Every method in here assumes that the storage has been appropriately
14 # safeguarded. This can be anything from flock() to some sort of manual
15 # mutex. But, it's the caller's responsability to make sure that this has
18 # Setup file and tag signatures. These should never change.
19 sub SIG_FILE () { 'DPDB' }
20 sub SIG_HEADER () { 'h' }
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' }
29 sub STALE_SIZE () { 1 }
31 # Please refer to the pack() documentation for further information
33 1 => 'C', # Unsigned char value (no order needed as it's just one byte)
34 2 => 'n', # Unsigned short in "network" (big-endian) order
35 4 => 'N', # Unsigned long in "network" (big-endian) order
36 8 => 'Q', # Usigned quad (no order specified, presumably machine-dependent)
39 ################################################################################
49 hash_size => 16, # In bytes
50 hash_chars => 256, # Number of chars the algorithm uses per byte
52 num_txns => 1, # The HEAD
53 trans_id => 0, # Default to the HEAD
55 data_sector_size => 64, # Size in bytes of each data sector
57 entries => {}, # This is the list of entries for transactions
61 # Never allow byte_size to be set directly.
62 delete $args->{byte_size};
63 if ( defined $args->{pack_size} ) {
64 if ( lc $args->{pack_size} eq 'small' ) {
65 $args->{byte_size} = 2;
67 elsif ( lc $args->{pack_size} eq 'medium' ) {
68 $args->{byte_size} = 4;
70 elsif ( lc $args->{pack_size} eq 'large' ) {
71 $args->{byte_size} = 8;
74 DBM::Deep->_throw_error( "Unknown pack_size value: '$args->{pack_size}'" );
78 # Grab the parameters we want to use
79 foreach my $param ( keys %$self ) {
80 next unless exists $args->{$param};
81 $self->{$param} = $args->{$param};
85 # Number of buckets per blist before another level of indexing is
86 # done. Increase this value for slightly greater speed, but larger database
87 # files. DO NOT decrease this value below 16, due to risk of recursive
90 if ( !defined $self->{max_buckets}
91 || !length $self->{max_buckets}
92 || $self->{max_buckets} =~ /\D/
93 || $self->{max_buckets} < 16
95 $self->{max_buckets} = '(undef)' if !defined $self->{max_buckets};
96 warn "Floor of max_buckets is 16. Setting it to 16 from '$self->{max_buckets}'\n";
97 $self->{max_buckets} = 16;
99 elsif ( $self->{max_buckets} > 256 ) {
100 warn "Ceiling of max_buckets is 256. Setting it to 256 from '$self->{max_buckets}'\n";
101 $self->{max_buckets} = 256;
104 if ( !defined $self->{num_txns}
105 || !length $self->{num_txns}
106 || $self->{num_txns} =~ /\D/
107 || $self->{num_txns} < 1
109 $self->{num_txns} = '(undef)' if !defined $self->{num_txns};
110 warn "Floor of num_txns is 1. Setting it to 1 from '$self->{num_txns}'\n";
111 $self->{num_txns} = 1;
113 elsif ( $self->{num_txns} > 255 ) {
114 warn "Ceiling of num_txns is 255. Setting it to 255 from '$self->{num_txns}'\n";
115 $self->{num_txns} = 255;
118 if ( !defined $self->{data_sector_size}
119 || !length $self->{data_sector_size}
120 || $self->{data_sector_size} =~ /\D/
121 || $self->{data_sector_size} < 32
123 $self->{data_sector_size} = '(undef)' if !defined $self->{data_sector_size};
124 warn "Floor of data_sector_size is 32. Setting it to 32 from '$self->{data_sector_size}'\n";
125 $self->{data_sector_size} = 32;
127 elsif ( $self->{data_sector_size} > 256 ) {
128 warn "Ceiling of data_sector_size is 256. Setting it to 256 from '$self->{data_sector_size}'\n";
129 $self->{data_sector_size} = 256;
132 if ( !$self->{digest} ) {
134 $self->{digest} = \&Digest::MD5::md5;
140 ################################################################################
144 my ($obj, $key) = @_;
146 # This will be a Reference sector
147 my $sector = $self->_load_sector( $obj->_base_offset )
150 if ( $sector->staleness != $obj->_staleness ) {
154 my $key_md5 = $self->_apply_digest( $key );
156 my $value_sector = $sector->get_data_for({
161 unless ( $value_sector ) {
162 $value_sector = DBM::Deep::Engine::Sector::Null->new({
167 $sector->write_data({
170 value => $value_sector,
174 return $value_sector->data;
181 # This will be a Reference sector
182 my $sector = $self->_load_sector( $obj->_base_offset )
183 or DBM::Deep->_throw_error( "How did get_classname fail (no sector for '$obj')?!" );
185 if ( $sector->staleness != $obj->_staleness ) {
189 return $sector->get_classname;
194 my ($obj, $key) = @_;
196 # This will be a Reference sector
197 my $sector = $self->_load_sector( $obj->_base_offset )
200 if ( $sector->staleness != $obj->_staleness ) {
204 my $data = $sector->get_data_for({
205 key_md5 => $self->_apply_digest( $key ),
209 # exists() returns 1 or '' for true/false.
210 return $data ? 1 : '';
215 my ($obj, $key) = @_;
217 my $sector = $self->_load_sector( $obj->_base_offset )
220 if ( $sector->staleness != $obj->_staleness ) {
224 return $sector->delete_key({
225 key_md5 => $self->_apply_digest( $key ),
232 my ($obj, $key, $value) = @_;
234 my $r = Scalar::Util::reftype( $value ) || '';
237 last if $r eq 'HASH';
238 last if $r eq 'ARRAY';
240 DBM::Deep->_throw_error(
241 "Storage of references of type '$r' is not supported."
246 if ( !defined $value ) {
247 $class = 'DBM::Deep::Engine::Sector::Null';
249 elsif ( $r eq 'ARRAY' || $r eq 'HASH' ) {
250 if ( $r eq 'ARRAY' && tied(@$value) ) {
251 DBM::Deep->_throw_error( "Cannot store something that is tied." );
253 if ( $r eq 'HASH' && tied(%$value) ) {
254 DBM::Deep->_throw_error( "Cannot store something that is tied." );
256 $class = 'DBM::Deep::Engine::Sector::Reference';
257 $type = substr( $r, 0, 1 );
260 $class = 'DBM::Deep::Engine::Sector::Scalar';
263 # This will be a Reference sector
264 my $sector = $self->_load_sector( $obj->_base_offset )
265 or DBM::Deep->_throw_error( "Cannot write to a deleted spot in DBM::Deep." );
267 if ( $sector->staleness != $obj->_staleness ) {
268 DBM::Deep->_throw_error( "Cannot write to a deleted spot in DBM::Deep.n" );
271 # Create this after loading the reference sector in case something bad happens.
272 # This way, we won't allocate value sector(s) needlessly.
273 my $value_sector = $class->new({
279 $sector->write_data({
281 key_md5 => $self->_apply_digest( $key ),
282 value => $value_sector,
285 # This code is to make sure we write all the values in the $value to the disk
286 # and to make sure all changes to $value after the assignment are reflected
287 # on disk. This may be counter-intuitive at first, but it is correct dwimmery.
288 # NOTE - simply tying $value won't perform a STORE on each value. Hence, the
289 # copy to a temp value.
290 if ( $r eq 'ARRAY' ) {
292 tie @$value, 'DBM::Deep', {
293 base_offset => $value_sector->offset,
294 staleness => $value_sector->staleness,
295 storage => $self->storage,
299 bless $value, 'DBM::Deep::Array' unless Scalar::Util::blessed( $value );
301 elsif ( $r eq 'HASH' ) {
303 tie %$value, 'DBM::Deep', {
304 base_offset => $value_sector->offset,
305 staleness => $value_sector->staleness,
306 storage => $self->storage,
311 bless $value, 'DBM::Deep::Hash' unless Scalar::Util::blessed( $value );
317 # XXX Add staleness here
320 my ($obj, $prev_key) = @_;
322 # XXX Need to add logic about resetting the iterator if any key in the reference has changed
323 unless ( $prev_key ) {
324 $obj->{iterator} = DBM::Deep::Iterator->new({
325 base_offset => $obj->_base_offset,
330 return $obj->{iterator}->get_next_key( $obj );
333 ################################################################################
339 # We're opening the file.
340 unless ( $obj->_base_offset ) {
341 my $bytes_read = $self->_read_file_header;
343 # Creating a new file
344 unless ( $bytes_read ) {
345 $self->_write_file_header;
347 # 1) Create Array/Hash entry
348 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
352 $obj->{base_offset} = $initial_reference->offset;
353 $obj->{staleness} = $initial_reference->staleness;
355 $self->storage->flush;
357 # Reading from an existing file
359 $obj->{base_offset} = $bytes_read;
360 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
362 offset => $obj->_base_offset,
364 unless ( $initial_reference ) {
365 DBM::Deep->_throw_error("Corrupted file, no master index record");
368 unless ($obj->_type eq $initial_reference->type) {
369 DBM::Deep->_throw_error("File type mismatch");
372 $obj->{staleness} = $initial_reference->staleness;
383 if ( $self->trans_id ) {
384 DBM::Deep->_throw_error( "Cannot begin_work within an active transaction" );
387 my @slots = $self->read_txn_slots;
388 for my $i ( 1 .. @slots ) {
391 $self->set_trans_id( $i );
394 $self->write_txn_slots( @slots );
396 if ( !$self->trans_id ) {
397 DBM::Deep->_throw_error( "Cannot begin_work - no available transactions" );
407 if ( !$self->trans_id ) {
408 DBM::Deep->_throw_error( "Cannot rollback without an active transaction" );
411 # Each entry is the file location for a bucket that has a modification for
412 # this transaction. The entries need to be expunged.
413 foreach my $entry (@{ $self->get_entries } ) {
414 # Remove the entry here
415 my $read_loc = $entry
418 + $self->trans_id * ( $self->byte_size + 4 );
420 my $data_loc = $self->storage->read_at( $read_loc, $self->byte_size );
421 $data_loc = unpack( $StP{$self->byte_size}, $data_loc );
422 $self->storage->print_at( $read_loc, pack( $StP{$self->byte_size}, 0 ) );
424 if ( $data_loc > 1 ) {
425 $self->_load_sector( $data_loc )->free;
429 $self->clear_entries;
431 my @slots = $self->read_txn_slots;
432 $slots[$self->trans_id] = 0;
433 $self->write_txn_slots( @slots );
434 $self->inc_txn_staleness_counter( $self->trans_id );
435 $self->set_trans_id( 0 );
444 if ( !$self->trans_id ) {
445 DBM::Deep->_throw_error( "Cannot commit without an active transaction" );
448 foreach my $entry (@{ $self->get_entries } ) {
449 # Overwrite the entry in head with the entry in trans_id
454 my $head_loc = $self->storage->read_at( $base, $self->byte_size );
455 $head_loc = unpack( $StP{$self->byte_size}, $head_loc );
456 my $trans_loc = $self->storage->read_at(
457 $base + $self->trans_id * ( $self->byte_size + 4 ), $self->byte_size,
460 $self->storage->print_at( $base, $trans_loc );
461 $self->storage->print_at(
462 $base + $self->trans_id * ( $self->byte_size + 4 ),
463 pack( $StP{$self->byte_size} . ' N', (0) x 2 ),
466 if ( $head_loc > 1 ) {
467 $self->_load_sector( $head_loc )->free;
471 $self->clear_entries;
473 my @slots = $self->read_txn_slots;
474 $slots[$self->trans_id] = 0;
475 $self->write_txn_slots( @slots );
476 $self->inc_txn_staleness_counter( $self->trans_id );
477 $self->set_trans_id( 0 );
484 return split '', unpack( 'b32',
485 $self->storage->read_at(
491 sub write_txn_slots {
493 $self->storage->print_at( $self->trans_loc,
494 pack( 'b32', join('', @_) ),
498 sub get_running_txn_ids {
500 my @transactions = $self->read_txn_slots;
501 my @trans_ids = grep { $transactions[$_] } 0 .. $#transactions;
504 sub get_txn_staleness_counter {
508 # Hardcode staleness of 0 for the HEAD
509 return 0 unless $trans_id;
512 $self->storage->read_at(
513 $self->trans_loc + 4 * $trans_id,
520 sub inc_txn_staleness_counter {
524 # Hardcode staleness of 0 for the HEAD
525 return unless $trans_id;
527 $self->storage->print_at(
528 $self->trans_loc + 4 * $trans_id,
529 pack( 'N', $self->get_txn_staleness_counter( $trans_id ) + 1 ),
535 return [ keys %{ $self->{entries}{$self->trans_id} ||= {} } ];
540 my ($trans_id, $loc) = @_;
542 $self->{entries}{$trans_id} ||= {};
543 $self->{entries}{$trans_id}{$loc} = undef;
546 # If the buckets are being relocated because of a reindexing, the entries
547 # mechanism needs to be made aware of it.
550 my ($old_loc, $new_loc) = @_;
553 while ( my ($trans_id, $locs) = each %{ $self->{entries} } ) {
554 foreach my $orig_loc ( keys %{ $locs } ) {
555 if ( $orig_loc == $old_loc ) {
556 delete $locs->{orig_loc};
557 $locs->{$new_loc} = undef;
566 delete $self->{entries}{$self->trans_id};
569 ################################################################################
572 my $header_fixed = length( SIG_FILE ) + 1 + 4 + 4;
573 my $this_file_version = 2;
575 sub _write_file_header {
578 my $nt = $self->num_txns;
580 my $header_var = 1 + 1 + 1 + 1 + 4 + 4 * $nt + 3 * $self->byte_size;
582 my $loc = $self->storage->request_space( $header_fixed + $header_var );
584 $self->storage->print_at( $loc,
587 pack('N', $this_file_version), # At this point, we're at 9 bytes
588 pack('N', $header_var), # header size
589 # --- Above is $header_fixed. Below is $header_var
590 pack('C', $self->byte_size),
592 # These shenanigans are to allow a 256 within a C
593 pack('C', $self->max_buckets - 1),
594 pack('C', $self->data_sector_size - 1),
597 pack('N', 0 ), # Transaction activeness bitfield
598 pack('N' . $nt, 0 x $nt ), # Transaction staleness counters
599 pack($StP{$self->byte_size}, 0), # Start of free chain (blist size)
600 pack($StP{$self->byte_size}, 0), # Start of free chain (data size)
601 pack($StP{$self->byte_size}, 0), # Start of free chain (index size)
604 #XXX Set these less fragilely
605 $self->set_trans_loc( $header_fixed + 4 );
606 $self->set_chains_loc( $header_fixed + 4 + 4 + 4 * $nt );
611 sub _read_file_header {
614 my $buffer = $self->storage->read_at( 0, $header_fixed );
615 return unless length($buffer);
617 my ($file_signature, $sig_header, $file_version, $size) = unpack(
621 unless ( $file_signature eq SIG_FILE ) {
622 $self->storage->close;
623 DBM::Deep->_throw_error( "Signature not found -- file is not a Deep DB" );
626 unless ( $sig_header eq SIG_HEADER ) {
627 $self->storage->close;
628 DBM::Deep->_throw_error( "Pre-1.00 file version found" );
631 unless ( $file_version == $this_file_version ) {
632 $self->storage->close;
633 DBM::Deep->_throw_error(
634 "Wrong file version found - " . $file_version .
635 " - expected " . $this_file_version
639 my $buffer2 = $self->storage->read_at( undef, $size );
640 my @values = unpack( 'C C C C', $buffer2 );
642 if ( @values != 4 || grep { !defined } @values ) {
643 $self->storage->close;
644 DBM::Deep->_throw_error("Corrupted file - bad header");
647 $self->set_trans_loc( $header_fixed + scalar(@values) );
648 $self->set_chains_loc( $header_fixed + scalar(@values) + 4 + 4 * $self->num_txns );
650 #XXX Add warnings if values weren't set right
651 @{$self}{qw(byte_size max_buckets data_sector_size num_txns)} = @values;
653 # These shenangians are to allow a 256 within a C
654 $self->{max_buckets} += 1;
655 $self->{data_sector_size} += 1;
657 my $header_var = scalar(@values) + 4 + 4 * $self->num_txns + 3 * $self->byte_size;
658 unless ( $size == $header_var ) {
659 $self->storage->close;
660 DBM::Deep->_throw_error( "Unexpected size found ($size <-> $header_var)." );
663 return length($buffer) + length($buffer2);
671 # Add a catch for offset of 0 or 1
672 return if $offset <= 1;
674 my $type = $self->storage->read_at( $offset, 1 );
675 return if $type eq chr(0);
677 if ( $type eq $self->SIG_ARRAY || $type eq $self->SIG_HASH ) {
678 return DBM::Deep::Engine::Sector::Reference->new({
684 # XXX Don't we need key_md5 here?
685 elsif ( $type eq $self->SIG_BLIST ) {
686 return DBM::Deep::Engine::Sector::BucketList->new({
692 elsif ( $type eq $self->SIG_INDEX ) {
693 return DBM::Deep::Engine::Sector::Index->new({
699 elsif ( $type eq $self->SIG_NULL ) {
700 return DBM::Deep::Engine::Sector::Null->new({
706 elsif ( $type eq $self->SIG_DATA ) {
707 return DBM::Deep::Engine::Sector::Scalar->new({
713 # This was deleted from under us, so just return and let the caller figure it out.
714 elsif ( $type eq $self->SIG_FREE ) {
718 DBM::Deep->_throw_error( "'$offset': Don't know what to do with type '$type'" );
723 return $self->{digest}->(@_);
726 sub _add_free_blist_sector { shift->_add_free_sector( 0, @_ ) }
727 sub _add_free_data_sector { shift->_add_free_sector( 1, @_ ) }
728 sub _add_free_index_sector { shift->_add_free_sector( 2, @_ ) }
730 sub _add_free_sector {
732 my ($multiple, $offset, $size) = @_;
734 my $chains_offset = $multiple * $self->byte_size;
736 my $storage = $self->storage;
738 # Increment staleness.
739 # XXX Can this increment+modulo be done by "&= 0x1" ?
740 my $staleness = unpack( $StP{STALE_SIZE()}, $storage->read_at( $offset + SIG_SIZE, STALE_SIZE ) );
741 $staleness = ($staleness + 1 ) % ( 2 ** ( 8 * STALE_SIZE ) );
742 $storage->print_at( $offset + SIG_SIZE, pack( $StP{STALE_SIZE()}, $staleness ) );
744 my $old_head = $storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
746 $storage->print_at( $self->chains_loc + $chains_offset,
747 pack( $StP{$self->byte_size}, $offset ),
750 # Record the old head in the new sector after the signature and staleness counter
751 $storage->print_at( $offset + SIG_SIZE + STALE_SIZE, $old_head );
754 sub _request_blist_sector { shift->_request_sector( 0, @_ ) }
755 sub _request_data_sector { shift->_request_sector( 1, @_ ) }
756 sub _request_index_sector { shift->_request_sector( 2, @_ ) }
758 sub _request_sector {
760 my ($multiple, $size) = @_;
762 my $chains_offset = $multiple * $self->byte_size;
764 my $old_head = $self->storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
765 my $loc = unpack( $StP{$self->byte_size}, $old_head );
767 # We don't have any free sectors of the right size, so allocate a new one.
769 my $offset = $self->storage->request_space( $size );
771 # Zero out the new sector. This also guarantees correct increases
773 $self->storage->print_at( $offset, chr(0) x $size );
778 # Read the new head after the signature and the staleness counter
779 my $new_head = $self->storage->read_at( $loc + SIG_SIZE + STALE_SIZE, $self->byte_size );
780 $self->storage->print_at( $self->chains_loc + $chains_offset, $new_head );
781 $self->storage->print_at(
782 $loc + SIG_SIZE + STALE_SIZE,
783 pack( $StP{$self->byte_size}, 0 ),
789 ################################################################################
791 sub storage { $_[0]{storage} }
792 sub byte_size { $_[0]{byte_size} }
793 sub hash_size { $_[0]{hash_size} }
794 sub hash_chars { $_[0]{hash_chars} }
795 sub num_txns { $_[0]{num_txns} }
796 sub max_buckets { $_[0]{max_buckets} }
797 sub blank_md5 { chr(0) x $_[0]->hash_size }
798 sub data_sector_size { $_[0]{data_sector_size} }
800 sub trans_id { $_[0]{trans_id} }
801 sub set_trans_id { $_[0]{trans_id} = $_[1] }
803 sub trans_loc { $_[0]{trans_loc} }
804 sub set_trans_loc { $_[0]{trans_loc} = $_[1] }
806 sub chains_loc { $_[0]{chains_loc} }
807 sub set_chains_loc { $_[0]{chains_loc} = $_[1] }
809 ################################################################################
811 package DBM::Deep::Iterator;
819 engine => $args->{engine},
820 base_offset => $args->{base_offset},
823 Scalar::Util::weaken( $self->{engine} );
828 sub reset { $_[0]{breadcrumbs} = [] }
830 sub get_sector_iterator {
834 my $sector = $self->{engine}->_load_sector( $loc )
837 if ( $sector->isa( 'DBM::Deep::Engine::Sector::Index' ) ) {
838 return DBM::Deep::Iterator::Index->new({
843 elsif ( $sector->isa( 'DBM::Deep::Engine::Sector::BucketList' ) ) {
844 return DBM::Deep::Iterator::BucketList->new({
850 DBM::Deep->_throw_error( "get_sector_iterator(): Why did $loc make a $sector?" );
857 my $crumbs = $self->{breadcrumbs};
858 my $e = $self->{engine};
860 unless ( @$crumbs ) {
861 # This will be a Reference sector
862 my $sector = $e->_load_sector( $self->{base_offset} )
863 # If no sector is found, thist must have been deleted from under us.
866 if ( $sector->staleness != $obj->_staleness ) {
870 my $loc = $sector->get_blist_loc
873 push @$crumbs, $self->get_sector_iterator( $loc );
878 unless ( @$crumbs ) {
883 my $iterator = $crumbs->[-1];
885 # This level is done.
886 if ( $iterator->at_end ) {
891 if ( $iterator->isa( 'DBM::Deep::Iterator::Index' ) ) {
892 # If we don't have any more, it will be caught at the
894 if ( my $next = $iterator->get_next_iterator ) {
895 push @$crumbs, $next;
900 unless ( $iterator->isa( 'DBM::Deep::Iterator::BucketList' ) ) {
901 DBM::Deep->_throw_error(
902 "Should have a bucketlist iterator here - instead have $iterator"
906 # At this point, we have a BucketList iterator
907 my $key = $iterator->get_next_key;
908 if ( defined $key ) {
911 #XXX else { $iterator->set_to_end() } ?
913 # We hit the end of the bucketlist iterator, so redo
917 DBM::Deep->_throw_error( "get_next_key(): How did we get here?" );
920 package DBM::Deep::Iterator::Index;
923 my $self = bless $_[1] => $_[0];
924 $self->{curr_index} = 0;
930 return $self->{curr_index} >= $self->{iterator}{engine}->hash_chars;
933 sub get_next_iterator {
938 return if $self->at_end;
939 $loc = $self->{sector}->get_entry( $self->{curr_index}++ );
942 return $self->{iterator}->get_sector_iterator( $loc );
945 package DBM::Deep::Iterator::BucketList;
948 my $self = bless $_[1] => $_[0];
949 $self->{curr_index} = 0;
955 return $self->{curr_index} >= $self->{iterator}{engine}->max_buckets;
961 return if $self->at_end;
963 my $idx = $self->{curr_index}++;
965 my $data_loc = $self->{sector}->get_data_location_for({
970 #XXX Do we want to add corruption checks here?
971 return $self->{sector}->get_key_for( $idx )->data;
974 package DBM::Deep::Engine::Sector;
977 my $self = bless $_[1], $_[0];
978 Scalar::Util::weaken( $self->{engine} );
984 #sub clone { DBM::Deep->_throw_error( "Must be implemented in the child class" ); }
986 sub engine { $_[0]{engine} }
987 sub offset { $_[0]{offset} }
988 sub type { $_[0]{type} }
992 return $self->engine->SIG_SIZE + $self->engine->STALE_SIZE;
998 my $e = $self->engine;
1000 $e->storage->print_at( $self->offset, $e->SIG_FREE );
1001 # Skip staleness counter
1002 $e->storage->print_at( $self->offset + $self->base_size,
1003 chr(0) x ($self->size - $self->base_size),
1006 my $free_meth = $self->free_meth;
1007 $e->$free_meth( $self->offset, $self->size );
1012 package DBM::Deep::Engine::Sector::Data;
1014 our @ISA = qw( DBM::Deep::Engine::Sector );
1017 sub size { $_[0]{engine}->data_sector_size }
1018 sub free_meth { return '_add_free_data_sector' }
1022 return ref($self)->new({
1023 engine => $self->engine,
1024 data => $self->data,
1025 type => $self->type,
1029 package DBM::Deep::Engine::Sector::Scalar;
1031 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1036 my $chain_loc = $self->chain_loc;
1038 $self->SUPER::free();
1041 $self->engine->_load_sector( $chain_loc )->free;
1047 sub type { $_[0]{engine}->SIG_DATA }
1051 my $engine = $self->engine;
1053 unless ( $self->offset ) {
1054 my $data_section = $self->size - $self->base_size - 1 * $engine->byte_size - 1;
1056 $self->{offset} = $engine->_request_data_sector( $self->size );
1058 my $data = delete $self->{data};
1059 my $dlen = length $data;
1061 my $curr_offset = $self->offset;
1062 while ( $continue ) {
1064 my $next_offset = 0;
1066 my ($leftover, $this_len, $chunk);
1067 if ( $dlen > $data_section ) {
1069 $this_len = $data_section;
1070 $chunk = substr( $data, 0, $this_len );
1072 $dlen -= $data_section;
1073 $next_offset = $engine->_request_data_sector( $self->size );
1074 $data = substr( $data, $this_len );
1077 $leftover = $data_section - $dlen;
1084 $engine->storage->print_at( $curr_offset, $self->type ); # Sector type
1086 $engine->storage->print_at( $curr_offset + $self->base_size,
1087 pack( $StP{$engine->byte_size}, $next_offset ), # Chain loc
1088 pack( $StP{1}, $this_len ), # Data length
1089 $chunk, # Data to be stored in this sector
1090 chr(0) x $leftover, # Zero-fill the rest
1093 $curr_offset = $next_offset;
1103 my $buffer = $self->engine->storage->read_at(
1104 $self->offset + $self->base_size + $self->engine->byte_size, 1
1107 return unpack( $StP{1}, $buffer );
1113 $StP{$self->engine->byte_size},
1114 $self->engine->storage->read_at(
1115 $self->offset + $self->base_size,
1116 $self->engine->byte_size,
1126 my $chain_loc = $self->chain_loc;
1128 $data .= $self->engine->storage->read_at(
1129 $self->offset + $self->base_size + $self->engine->byte_size + 1, $self->data_length,
1132 last unless $chain_loc;
1134 $self = $self->engine->_load_sector( $chain_loc );
1140 package DBM::Deep::Engine::Sector::Null;
1142 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1144 sub type { $_[0]{engine}->SIG_NULL }
1145 sub data_length { 0 }
1151 my $engine = $self->engine;
1153 unless ( $self->offset ) {
1154 my $leftover = $self->size - $self->base_size - 1 * $engine->byte_size - 1;
1156 $self->{offset} = $engine->_request_data_sector( $self->size );
1157 $engine->storage->print_at( $self->offset, $self->type ); # Sector type
1158 # Skip staleness counter
1159 $engine->storage->print_at( $self->offset + $self->base_size,
1160 pack( $StP{$engine->byte_size}, 0 ), # Chain loc
1161 pack( $StP{1}, $self->data_length ), # Data length
1162 chr(0) x $leftover, # Zero-fill the rest
1169 package DBM::Deep::Engine::Sector::Reference;
1171 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1176 my $e = $self->engine;
1178 unless ( $self->offset ) {
1179 my $classname = Scalar::Util::blessed( delete $self->{data} );
1180 my $leftover = $self->size - $self->base_size - 2 * $e->byte_size;
1182 my $class_offset = 0;
1183 if ( defined $classname ) {
1184 my $class_sector = DBM::Deep::Engine::Sector::Scalar->new({
1188 $class_offset = $class_sector->offset;
1191 $self->{offset} = $e->_request_data_sector( $self->size );
1192 $e->storage->print_at( $self->offset, $self->type ); # Sector type
1193 # Skip staleness counter
1194 $e->storage->print_at( $self->offset + $self->base_size,
1195 pack( $StP{$e->byte_size}, 0 ), # Index/BList loc
1196 pack( $StP{$e->byte_size}, $class_offset ), # Classname loc
1197 chr(0) x $leftover, # Zero-fill the rest
1201 $self->{type} = $e->storage->read_at( $self->offset, 1 );
1204 $self->{staleness} = unpack(
1205 $StP{$e->STALE_SIZE},
1206 $e->storage->read_at( $self->offset + $e->SIG_SIZE, $e->STALE_SIZE ),
1215 my $blist_loc = $self->get_blist_loc;
1216 $self->engine->_load_sector( $blist_loc )->free if $blist_loc;
1218 my $class_loc = $self->get_class_offset;
1219 $self->engine->_load_sector( $class_loc )->free if $class_loc;
1221 $self->SUPER::free();
1224 sub staleness { $_[0]{staleness} }
1230 # Assume that the head is not allowed unless otherwise specified.
1231 $args->{allow_head} = 0 unless exists $args->{allow_head};
1233 # Assume we don't create a new blist location unless otherwise specified.
1234 $args->{create} = 0 unless exists $args->{create};
1236 my $blist = $self->get_bucket_list({
1237 key_md5 => $args->{key_md5},
1238 key => $args->{key},
1239 create => $args->{create},
1241 return unless $blist && $blist->{found};
1243 # At this point, $blist knows where the md5 is. What it -doesn't- know yet
1244 # is whether or not this transaction has this key. That's part of the next
1246 my $location = $blist->get_data_location_for({
1247 allow_head => $args->{allow_head},
1250 return $self->engine->_load_sector( $location );
1257 my $blist = $self->get_bucket_list({
1258 key_md5 => $args->{key_md5},
1259 key => $args->{key},
1261 }) or DBM::Deep->_throw_error( "How did write_data fail (no blist)?!" );
1263 # Handle any transactional bookkeeping.
1264 if ( $self->engine->trans_id ) {
1265 if ( ! $blist->has_md5 ) {
1266 $blist->mark_deleted({
1272 my @trans_ids = $self->engine->get_running_txn_ids;
1273 if ( $blist->has_md5 ) {
1275 my $old_value = $blist->get_data_for;
1276 foreach my $other_trans_id ( @trans_ids ) {
1277 next if $blist->get_data_location_for({
1278 trans_id => $other_trans_id,
1282 trans_id => $other_trans_id,
1283 key => $args->{key},
1284 key_md5 => $args->{key_md5},
1285 value => $old_value->clone,
1292 foreach my $other_trans_id ( @trans_ids ) {
1293 #XXX This doesn't seem to possible to ever happen . . .
1294 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1295 $blist->mark_deleted({
1296 trans_id => $other_trans_id,
1303 #XXX Is this safe to do transactionally?
1304 # Free the place we're about to write to.
1305 if ( $blist->get_data_location_for({ allow_head => 0 }) ) {
1306 $blist->get_data_for({ allow_head => 0 })->free;
1310 key => $args->{key},
1311 key_md5 => $args->{key_md5},
1312 value => $args->{value},
1320 # XXX What should happen if this fails?
1321 my $blist = $self->get_bucket_list({
1322 key_md5 => $args->{key_md5},
1323 }) or DBM::Deep->_throw_error( "How did delete_key fail (no blist)?!" );
1325 # Save the location so that we can free the data
1326 my $location = $blist->get_data_location_for({
1329 my $old_value = $location && $self->engine->_load_sector( $location );
1331 my @trans_ids = $self->engine->get_running_txn_ids;
1333 if ( $self->engine->trans_id == 0 ) {
1335 foreach my $other_trans_id ( @trans_ids ) {
1336 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1338 trans_id => $other_trans_id,
1339 key => $args->{key},
1340 key_md5 => $args->{key_md5},
1341 value => $old_value->clone,
1349 $blist->mark_deleted( $args );
1352 $data = $old_value->data;
1357 $data = $blist->delete_md5( $args );
1366 my $e = $self->engine;
1367 my $blist_loc = $e->storage->read_at( $self->offset + $self->base_size, $e->byte_size );
1368 return unpack( $StP{$e->byte_size}, $blist_loc );
1371 sub get_bucket_list {
1376 # XXX Add in check here for recycling?
1378 my $engine = $self->engine;
1380 my $blist_loc = $self->get_blist_loc;
1382 # There's no index or blist yet
1383 unless ( $blist_loc ) {
1384 return unless $args->{create};
1386 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1388 key_md5 => $args->{key_md5},
1391 $engine->storage->print_at( $self->offset + $self->base_size,
1392 pack( $StP{$engine->byte_size}, $blist->offset ),
1398 my $sector = $engine->_load_sector( $blist_loc )
1399 or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
1401 my $last_sector = undef;
1402 while ( $sector->isa( 'DBM::Deep::Engine::Sector::Index' ) ) {
1403 $blist_loc = $sector->get_entry( ord( substr( $args->{key_md5}, $i++, 1 ) ) );
1404 $last_sector = $sector;
1406 $sector = $engine->_load_sector( $blist_loc )
1407 or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
1415 # This means we went through the Index sector(s) and found an empty slot
1416 unless ( $sector ) {
1417 return unless $args->{create};
1419 DBM::Deep->_throw_error( "No last_sector when attempting to build a new entry" )
1420 unless $last_sector;
1422 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1424 key_md5 => $args->{key_md5},
1427 $last_sector->set_entry( ord( substr( $args->{key_md5}, $i - 1, 1 ) ) => $blist->offset );
1432 $sector->find_md5( $args->{key_md5} );
1434 # See whether or not we need to reindex the bucketlist
1435 if ( !$sector->has_md5 && $args->{create} && $sector->{idx} == -1 ) {
1436 my $new_index = DBM::Deep::Engine::Sector::Index->new({
1441 #XXX q.v. the comments for this function.
1442 foreach my $entry ( $sector->chopped_up ) {
1443 my ($spot, $md5) = @{$entry};
1444 my $idx = ord( substr( $md5, $i, 1 ) );
1446 # XXX This is inefficient
1447 my $blist = $blist_cache{$idx}
1448 ||= DBM::Deep::Engine::Sector::BucketList->new({
1452 $new_index->set_entry( $idx => $blist->offset );
1454 my $new_spot = $blist->write_at_next_open( $md5 );
1455 $engine->reindex_entry( $spot => $new_spot );
1458 # Handle the new item separately.
1460 my $idx = ord( substr( $args->{key_md5}, $i, 1 ) );
1461 my $blist = $blist_cache{$idx}
1462 ||= DBM::Deep::Engine::Sector::BucketList->new({
1466 $new_index->set_entry( $idx => $blist->offset );
1469 $blist->find_md5( $args->{key_md5} );
1471 key => $args->{key},
1472 key_md5 => $args->{key_md5},
1473 value => DBM::Deep::Engine::Sector::Null->new({
1480 if ( $last_sector ) {
1481 $last_sector->set_entry(
1482 ord( substr( $args->{key_md5}, $i - 1, 1 ) ),
1486 $engine->storage->print_at( $self->offset + $self->base_size,
1487 pack( $StP{$engine->byte_size}, $new_index->offset ),
1493 $sector = $blist_cache{ ord( substr( $args->{key_md5}, $i, 1 ) ) };
1494 $sector->find_md5( $args->{key_md5} );
1500 sub get_class_offset {
1503 my $e = $self->engine;
1505 $StP{$e->byte_size},
1506 $e->storage->read_at(
1507 $self->offset + $self->base_size + 1 * $e->byte_size, $e->byte_size,
1515 my $class_offset = $self->get_class_offset;
1517 return unless $class_offset;
1519 return $self->engine->_load_sector( $class_offset )->data;
1522 #XXX Add singleton handling here
1526 my $new_obj = DBM::Deep->new({
1527 type => $self->type,
1528 base_offset => $self->offset,
1529 staleness => $self->staleness,
1530 storage => $self->engine->storage,
1531 engine => $self->engine,
1534 if ( $self->engine->storage->{autobless} ) {
1535 my $classname = $self->get_classname;
1536 if ( defined $classname ) {
1537 bless $new_obj, $classname;
1544 package DBM::Deep::Engine::Sector::BucketList;
1546 our @ISA = qw( DBM::Deep::Engine::Sector );
1551 my $engine = $self->engine;
1553 unless ( $self->offset ) {
1554 my $leftover = $self->size - $self->base_size;
1556 $self->{offset} = $engine->_request_blist_sector( $self->size );
1557 $engine->storage->print_at( $self->offset, $engine->SIG_BLIST ); # Sector type
1558 # Skip staleness counter
1559 $engine->storage->print_at( $self->offset + $self->base_size,
1560 chr(0) x $leftover, # Zero-fill the data
1564 if ( $self->{key_md5} ) {
1573 unless ( $self->{size} ) {
1574 my $e = $self->engine;
1575 # Base + numbuckets * bucketsize
1576 $self->{size} = $self->base_size + $e->max_buckets * $self->bucket_size;
1578 return $self->{size};
1581 sub free_meth { return '_add_free_blist_sector' }
1585 unless ( $self->{bucket_size} ) {
1586 my $e = $self->engine;
1587 # Key + head (location) + transactions (location + staleness-counter)
1588 my $location_size = $e->byte_size + $e->num_txns * ( $e->byte_size + 4 );
1589 $self->{bucket_size} = $e->hash_size + $location_size;
1591 return $self->{bucket_size};
1594 # XXX This is such a poor hack. I need to rethink this code.
1598 my $e = $self->engine;
1601 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
1602 my $spot = $self->offset + $self->base_size + $idx * $self->bucket_size;
1603 my $md5 = $e->storage->read_at( $spot, $e->hash_size );
1605 #XXX If we're chopping, why would we ever have the blank_md5?
1606 last if $md5 eq $e->blank_md5;
1608 my $rest = $e->storage->read_at( undef, $self->bucket_size - $e->hash_size );
1609 push @buckets, [ $spot, $md5 . $rest ];
1615 sub write_at_next_open {
1619 #XXX This is such a hack!
1620 $self->{_next_open} = 0 unless exists $self->{_next_open};
1622 my $spot = $self->offset + $self->base_size + $self->{_next_open}++ * $self->bucket_size;
1623 $self->engine->storage->print_at( $spot, $entry );
1630 unless ( exists $self->{found} ) {
1633 return $self->{found};
1639 $self->{found} = undef;
1643 $self->{key_md5} = shift;
1646 # If we don't have an MD5, then what are we supposed to do?
1647 unless ( exists $self->{key_md5} ) {
1648 DBM::Deep->_throw_error( "Cannot find_md5 without a key_md5 set" );
1651 my $e = $self->engine;
1652 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
1653 my $potential = $e->storage->read_at(
1654 $self->offset + $self->base_size + $idx * $self->bucket_size, $e->hash_size,
1657 if ( $potential eq $e->blank_md5 ) {
1658 $self->{idx} = $idx;
1662 if ( $potential eq $self->{key_md5} ) {
1664 $self->{idx} = $idx;
1676 DBM::Deep->_throw_error( "write_md5: no key" ) unless exists $args->{key};
1677 DBM::Deep->_throw_error( "write_md5: no key_md5" ) unless exists $args->{key_md5};
1678 DBM::Deep->_throw_error( "write_md5: no value" ) unless exists $args->{value};
1680 my $engine = $self->engine;
1682 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
1684 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1685 $engine->add_entry( $args->{trans_id}, $spot );
1687 unless ($self->{found}) {
1688 my $key_sector = DBM::Deep::Engine::Sector::Scalar->new({
1690 data => $args->{key},
1693 $engine->storage->print_at( $spot,
1695 pack( $StP{$engine->byte_size}, $key_sector->offset ),
1700 + $engine->hash_size
1701 + $engine->byte_size
1702 + $args->{trans_id} * ( $engine->byte_size + 4 );
1704 $engine->storage->print_at( $loc,
1705 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
1706 pack( 'N', $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
1715 my $engine = $self->engine;
1717 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
1719 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1720 $engine->add_entry( $args->{trans_id}, $spot );
1723 + $engine->hash_size
1724 + $engine->byte_size
1725 + $args->{trans_id} * ( $engine->byte_size + 4 );
1727 $engine->storage->print_at( $loc,
1728 pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
1729 pack( 'N', $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
1737 my $engine = $self->engine;
1738 return undef unless $self->{found};
1740 # Save the location so that we can free the data
1741 my $location = $self->get_data_location_for({
1744 my $key_sector = $self->get_key_for;
1746 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1747 $engine->storage->print_at( $spot,
1748 $engine->storage->read_at(
1749 $spot + $self->bucket_size,
1750 $self->bucket_size * ( $engine->max_buckets - $self->{idx} - 1 ),
1752 chr(0) x $self->bucket_size,
1757 my $data_sector = $self->engine->_load_sector( $location );
1758 my $data = $data_sector->data;
1764 sub get_data_location_for {
1769 $args->{allow_head} = 0 unless exists $args->{allow_head};
1770 $args->{trans_id} = $self->engine->trans_id unless exists $args->{trans_id};
1771 $args->{idx} = $self->{idx} unless exists $args->{idx};
1773 my $e = $self->engine;
1775 my $spot = $self->offset + $self->base_size
1776 + $args->{idx} * $self->bucket_size
1779 + $args->{trans_id} * ( $e->byte_size + 4 );
1781 my $buffer = $e->storage->read_at(
1785 my ($loc, $staleness) = unpack( $StP{$e->byte_size} . ' N', $buffer );
1787 # We have found an entry that is old, so get rid of it
1788 if ( $staleness != (my $s = $e->get_txn_staleness_counter( $args->{trans_id} ) ) ) {
1789 $e->storage->print_at(
1791 pack( $StP{$e->byte_size} . ' N', (0) x 2 ),
1796 # If we're in a transaction and we never wrote to this location, try the
1798 if ( $args->{trans_id} && !$loc && $args->{allow_head} ) {
1799 return $self->get_data_location_for({
1802 idx => $args->{idx},
1805 return $loc <= 1 ? 0 : $loc;
1813 return unless $self->{found};
1814 my $location = $self->get_data_location_for({
1815 allow_head => $args->{allow_head},
1817 return $self->engine->_load_sector( $location );
1823 $idx = $self->{idx} unless defined $idx;
1825 if ( $idx >= $self->engine->max_buckets ) {
1826 DBM::Deep->_throw_error( "get_key_for(): Attempting to retrieve $idx" );
1829 my $location = $self->engine->storage->read_at(
1830 $self->offset + $self->base_size + $idx * $self->bucket_size + $self->engine->hash_size,
1831 $self->engine->byte_size,
1833 $location = unpack( $StP{$self->engine->byte_size}, $location );
1834 DBM::Deep->_throw_error( "get_key_for: No location?" ) unless $location;
1836 return $self->engine->_load_sector( $location );
1839 package DBM::Deep::Engine::Sector::Index;
1841 our @ISA = qw( DBM::Deep::Engine::Sector );
1846 my $engine = $self->engine;
1848 unless ( $self->offset ) {
1849 my $leftover = $self->size - $self->base_size;
1851 $self->{offset} = $engine->_request_index_sector( $self->size );
1852 $engine->storage->print_at( $self->offset, $engine->SIG_INDEX ); # Sector type
1853 # Skip staleness counter
1854 $engine->storage->print_at( $self->offset + $self->base_size,
1855 chr(0) x $leftover, # Zero-fill the rest
1864 unless ( $self->{size} ) {
1865 my $e = $self->engine;
1866 $self->{size} = $self->base_size + $e->byte_size * $e->hash_chars;
1868 return $self->{size};
1871 sub free_meth { return '_add_free_index_sector' }
1875 my $e = $self->engine;
1877 for my $i ( 0 .. $e->hash_chars - 1 ) {
1878 my $l = $self->get_entry( $i ) or next;
1879 $e->_load_sector( $l )->free;
1882 $self->SUPER::free();
1888 return $self->offset + $self->base_size + $idx * $self->engine->byte_size;
1895 my $e = $self->engine;
1897 DBM::Deep->_throw_error( "get_entry: Out of range ($idx)" )
1898 if $idx < 0 || $idx >= $e->hash_chars;
1901 $StP{$e->byte_size},
1902 $e->storage->read_at( $self->_loc_for( $idx ), $e->byte_size ),
1908 my ($idx, $loc) = @_;
1910 my $e = $self->engine;
1912 DBM::Deep->_throw_error( "set_entry: Out of range ($idx)" )
1913 if $idx < 0 || $idx >= $e->hash_chars;
1915 $self->engine->storage->print_at(
1916 $self->_loc_for( $idx ),
1917 pack( $StP{$e->byte_size}, $loc ),