1 package DBM::Deep::Engine;
8 our $VERSION = q(1.0010);
10 # Never import symbols into our namespace. We are a class, not a library.
16 # * Every method in here assumes that the storage has been appropriately
17 # safeguarded. This can be anything from flock() to some sort of manual
18 # mutex. But, it's the caller's responsability to make sure that this has
21 # Setup file and tag signatures. These should never change.
22 sub SIG_FILE () { 'DPDB' }
23 sub SIG_HEADER () { 'h' }
24 sub SIG_HASH () { 'H' }
25 sub SIG_ARRAY () { 'A' }
26 sub SIG_NULL () { 'N' }
27 sub SIG_DATA () { 'D' }
28 sub SIG_INDEX () { 'I' }
29 sub SIG_BLIST () { 'B' }
30 sub SIG_FREE () { 'F' }
35 # Please refer to the pack() documentation for further information
37 1 => 'C', # Unsigned char value (no order needed as it's just one byte)
38 2 => 'n', # Unsigned short in "network" (big-endian) order
39 4 => 'N', # Unsigned long in "network" (big-endian) order
40 8 => 'Q', # Usigned quad (no order specified, presumably machine-dependent)
43 ################################################################################
53 hash_size => 16, # In bytes
54 hash_chars => 256, # Number of chars the algorithm uses per byte
56 num_txns => 1, # The HEAD
57 trans_id => 0, # Default to the HEAD
59 data_sector_size => 64, # Size in bytes of each data sector
61 entries => {}, # This is the list of entries for transactions
65 # Never allow byte_size to be set directly.
66 delete $args->{byte_size};
67 if ( defined $args->{pack_size} ) {
68 if ( lc $args->{pack_size} eq 'small' ) {
69 $args->{byte_size} = 2;
71 elsif ( lc $args->{pack_size} eq 'medium' ) {
72 $args->{byte_size} = 4;
74 elsif ( lc $args->{pack_size} eq 'large' ) {
75 $args->{byte_size} = 8;
78 DBM::Deep->_throw_error( "Unknown pack_size value: '$args->{pack_size}'" );
82 # Grab the parameters we want to use
83 foreach my $param ( keys %$self ) {
84 next unless exists $args->{$param};
85 $self->{$param} = $args->{$param};
89 max_buckets => { floor => 16, ceil => 256 },
90 num_txns => { floor => 1, ceil => 255 },
91 data_sector_size => { floor => 32, ceil => 256 },
94 while ( my ($attr, $c) = each %validations ) {
95 if ( !defined $self->{$attr}
96 || !length $self->{$attr}
97 || $self->{$attr} =~ /\D/
98 || $self->{$attr} < $c->{floor}
100 $self->{$attr} = '(undef)' if !defined $self->{$attr};
101 warn "Floor of $attr is $c->{floor}. Setting it to $c->{floor} from '$self->{$attr}'\n";
102 $self->{$attr} = $c->{floor};
104 elsif ( $self->{$attr} > $c->{ceil} ) {
105 warn "Ceiling of $attr is $c->{ceil}. Setting it to $c->{ceil} from '$self->{$attr}'\n";
106 $self->{$attr} = $c->{ceil};
110 if ( !$self->{digest} ) {
112 $self->{digest} = \&Digest::MD5::md5;
118 ################################################################################
122 my ($obj, $key) = @_;
124 # This will be a Reference sector
125 my $sector = $self->_load_sector( $obj->_base_offset )
128 if ( $sector->staleness != $obj->_staleness ) {
132 my $key_md5 = $self->_apply_digest( $key );
134 my $value_sector = $sector->get_data_for({
139 unless ( $value_sector ) {
140 $value_sector = DBM::Deep::Engine::Sector::Null->new({
145 $sector->write_data({
148 value => $value_sector,
152 return $value_sector->data;
159 # This will be a Reference sector
160 my $sector = $self->_load_sector( $obj->_base_offset )
161 or DBM::Deep->_throw_error( "How did get_classname fail (no sector for '$obj')?!" );
163 if ( $sector->staleness != $obj->_staleness ) {
167 return $sector->get_classname;
172 my ($obj, $old_key, $new_key) = @_;
174 # This will be a Reference sector
175 my $sector = $self->_load_sector( $obj->_base_offset )
176 or DBM::Deep->_throw_error( "How did get_classname fail (no sector for '$obj')?!" );
178 if ( $sector->staleness != $obj->_staleness ) {
182 my $old_md5 = $self->_apply_digest( $old_key );
184 my $value_sector = $sector->get_data_for({
189 unless ( $value_sector ) {
190 $value_sector = DBM::Deep::Engine::Sector::Null->new({
195 $sector->write_data({
198 value => $value_sector,
202 if ( $value_sector->isa( 'DBM::Deep::Engine::Sector::Reference' ) ) {
203 $sector->write_data({
205 key_md5 => $self->_apply_digest( $new_key ),
206 value => $value_sector,
208 $value_sector->increment_refcount;
211 $sector->write_data({
213 key_md5 => $self->_apply_digest( $new_key ),
214 value => $value_sector->clone,
221 my ($obj, $key) = @_;
223 # This will be a Reference sector
224 my $sector = $self->_load_sector( $obj->_base_offset )
227 if ( $sector->staleness != $obj->_staleness ) {
231 my $data = $sector->get_data_for({
232 key_md5 => $self->_apply_digest( $key ),
236 # exists() returns 1 or '' for true/false.
237 return $data ? 1 : '';
242 my ($obj, $key) = @_;
244 my $sector = $self->_load_sector( $obj->_base_offset )
247 if ( $sector->staleness != $obj->_staleness ) {
251 return $sector->delete_key({
252 key_md5 => $self->_apply_digest( $key ),
259 my ($obj, $key, $value) = @_;
261 my $r = Scalar::Util::reftype( $value ) || '';
264 last if $r eq 'HASH';
265 last if $r eq 'ARRAY';
267 DBM::Deep->_throw_error(
268 "Storage of references of type '$r' is not supported."
272 # This will be a Reference sector
273 my $sector = $self->_load_sector( $obj->_base_offset )
274 or DBM::Deep->_throw_error( "Cannot write to a deleted spot in DBM::Deep." );
276 if ( $sector->staleness != $obj->_staleness ) {
277 DBM::Deep->_throw_error( "Cannot write to a deleted spot in DBM::Deep.n" );
281 if ( !defined $value ) {
282 $class = 'DBM::Deep::Engine::Sector::Null';
284 elsif ( $r eq 'ARRAY' || $r eq 'HASH' ) {
287 # Checking if $value is tied and getting it's underlying variable
290 if ( $r eq 'ARRAY' ) {
291 $tmpvar = tied @$value;
292 } elsif ( $r eq 'HASH' ) {
293 $tmpvar = tied %$value;
297 # Checking if underlying variable is a DBM::Deep instance
299 my $is_ref_dbm_deep = eval { local $SIG{'__DIE__'}; $tmpvar->isa( 'DBM::Deep' ); };
300 if ( $is_ref_dbm_deep ) {
302 # Checking if storage of destination and source variables is the same
304 if ( $tmpvar->_engine->storage == $self->storage ) {
306 # If yes - loading source sector and getting its data reference address
308 my $value_sector = $self->_load_sector( $tmpvar->_base_offset );
309 my $data_addr = Scalar::Util::refaddr( $value_sector->data );
312 # Getting destination reference address for data by key
314 if ( Scalar::Util::reftype( $sector->data ) eq 'ARRAY' ) {
315 $origin_addr = Scalar::Util::refaddr( ${$sector->data}[$key] );
316 } elsif ( Scalar::Util::reftype( $sector->data ) eq 'HASH' ) {
317 $origin_addr = Scalar::Util::refaddr( ${$sector->data}{$key} );
321 # Do nothing if reference addresses of source and destination data are same
323 if (defined $data_addr && defined $origin_addr) {
324 return 1 if ($data_addr == $origin_addr);
327 DBM::Deep->_throw_error( "Cannot store values across DBM::Deep files. Please use export() instead." );
331 my $is_dbm_deep = eval { local $SIG{'__DIE__'}; $value->isa( 'DBM::Deep' ); };
332 if ( $is_dbm_deep ) {
333 if ( $value->_engine->storage == $self->storage ) {
334 my $value_sector = $self->_load_sector( $value->_base_offset );
335 $sector->write_data({
337 key_md5 => $self->_apply_digest( $key ),
338 value => $value_sector,
340 $value_sector->increment_refcount;
344 DBM::Deep->_throw_error( "Cannot store values across DBM::Deep files. Please use export() instead." );
346 if ( $r eq 'ARRAY' && tied(@$value) ) {
347 DBM::Deep->_throw_error( "Cannot store something that is tied." );
349 if ( $r eq 'HASH' && tied(%$value) ) {
350 DBM::Deep->_throw_error( "Cannot store something that is tied." );
352 $class = 'DBM::Deep::Engine::Sector::Reference';
353 $type = substr( $r, 0, 1 );
356 if ( tied($value) ) {
357 DBM::Deep->_throw_error( "Cannot store something that is tied." );
359 $class = 'DBM::Deep::Engine::Sector::Scalar';
362 # Create this after loading the reference sector in case something bad happens.
363 # This way, we won't allocate value sector(s) needlessly.
364 my $value_sector = $class->new({
370 $sector->write_data({
372 key_md5 => $self->_apply_digest( $key ),
373 value => $value_sector,
376 # This code is to make sure we write all the values in the $value to the disk
377 # and to make sure all changes to $value after the assignment are reflected
378 # on disk. This may be counter-intuitive at first, but it is correct dwimmery.
379 # NOTE - simply tying $value won't perform a STORE on each value. Hence, the
380 # copy to a temp value.
381 if ( $r eq 'ARRAY' ) {
383 tie @$value, 'DBM::Deep', {
384 base_offset => $value_sector->offset,
385 staleness => $value_sector->staleness,
386 storage => $self->storage,
390 bless $value, 'DBM::Deep::Array' unless Scalar::Util::blessed( $value );
392 elsif ( $r eq 'HASH' ) {
394 tie %$value, 'DBM::Deep', {
395 base_offset => $value_sector->offset,
396 staleness => $value_sector->staleness,
397 storage => $self->storage,
402 bless $value, 'DBM::Deep::Hash' unless Scalar::Util::blessed( $value );
408 # XXX Add staleness here
411 my ($obj, $prev_key) = @_;
413 # XXX Need to add logic about resetting the iterator if any key in the reference has changed
414 unless ( $prev_key ) {
415 $obj->{iterator} = DBM::Deep::Iterator->new({
416 base_offset => $obj->_base_offset,
421 return $obj->{iterator}->get_next_key( $obj );
424 ################################################################################
430 # We're opening the file.
431 unless ( $obj->_base_offset ) {
432 my $bytes_read = $self->_read_file_header;
434 # Creating a new file
435 unless ( $bytes_read ) {
436 $self->_write_file_header;
438 # 1) Create Array/Hash entry
439 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
443 $obj->{base_offset} = $initial_reference->offset;
444 $obj->{staleness} = $initial_reference->staleness;
446 $self->storage->flush;
448 # Reading from an existing file
450 $obj->{base_offset} = $bytes_read;
451 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
453 offset => $obj->_base_offset,
455 unless ( $initial_reference ) {
456 DBM::Deep->_throw_error("Corrupted file, no master index record");
459 unless ($obj->_type eq $initial_reference->type) {
460 DBM::Deep->_throw_error("File type mismatch");
463 $obj->{staleness} = $initial_reference->staleness;
474 if ( $self->trans_id ) {
475 DBM::Deep->_throw_error( "Cannot begin_work within an active transaction" );
478 my @slots = $self->read_txn_slots;
480 for my $i ( 0 .. $#slots ) {
484 $self->set_trans_id( $i + 1 );
489 DBM::Deep->_throw_error( "Cannot allocate transaction ID" );
491 $self->write_txn_slots( @slots );
493 if ( !$self->trans_id ) {
494 DBM::Deep->_throw_error( "Cannot begin_work - no available transactions" );
504 if ( !$self->trans_id ) {
505 DBM::Deep->_throw_error( "Cannot rollback without an active transaction" );
508 # Each entry is the file location for a bucket that has a modification for
509 # this transaction. The entries need to be expunged.
510 foreach my $entry (@{ $self->get_entries } ) {
511 # Remove the entry here
512 my $read_loc = $entry
516 + ($self->trans_id - 1) * ( $self->byte_size + $STALE_SIZE );
518 my $data_loc = $self->storage->read_at( $read_loc, $self->byte_size );
519 $data_loc = unpack( $StP{$self->byte_size}, $data_loc );
520 $self->storage->print_at( $read_loc, pack( $StP{$self->byte_size}, 0 ) );
522 if ( $data_loc > 1 ) {
523 $self->_load_sector( $data_loc )->free;
527 $self->clear_entries;
529 my @slots = $self->read_txn_slots;
530 $slots[$self->trans_id-1] = 0;
531 $self->write_txn_slots( @slots );
532 $self->inc_txn_staleness_counter( $self->trans_id );
533 $self->set_trans_id( 0 );
542 if ( !$self->trans_id ) {
543 DBM::Deep->_throw_error( "Cannot commit without an active transaction" );
546 foreach my $entry (@{ $self->get_entries } ) {
547 # Overwrite the entry in head with the entry in trans_id
552 my $head_loc = $self->storage->read_at( $base, $self->byte_size );
553 $head_loc = unpack( $StP{$self->byte_size}, $head_loc );
555 my $spot = $base + $self->byte_size + ($self->trans_id - 1) * ( $self->byte_size + $STALE_SIZE );
556 my $trans_loc = $self->storage->read_at(
557 $spot, $self->byte_size,
560 $self->storage->print_at( $base, $trans_loc );
561 $self->storage->print_at(
563 pack( $StP{$self->byte_size} . ' ' . $StP{$STALE_SIZE}, (0) x 2 ),
566 if ( $head_loc > 1 ) {
567 $self->_load_sector( $head_loc )->free;
571 $self->clear_entries;
573 my @slots = $self->read_txn_slots;
574 $slots[$self->trans_id-1] = 0;
575 $self->write_txn_slots( @slots );
576 $self->inc_txn_staleness_counter( $self->trans_id );
577 $self->set_trans_id( 0 );
584 my $bl = $self->txn_bitfield_len;
585 my $num_bits = $bl * 8;
586 return split '', unpack( 'b'.$num_bits,
587 $self->storage->read_at(
588 $self->trans_loc, $bl,
593 sub write_txn_slots {
595 my $num_bits = $self->txn_bitfield_len * 8;
596 $self->storage->print_at( $self->trans_loc,
597 pack( 'b'.$num_bits, join('', @_) ),
601 sub get_running_txn_ids {
603 my @transactions = $self->read_txn_slots;
604 my @trans_ids = map { $_+1} grep { $transactions[$_] } 0 .. $#transactions;
607 sub get_txn_staleness_counter {
611 # Hardcode staleness of 0 for the HEAD
612 return 0 unless $trans_id;
614 return unpack( $StP{$STALE_SIZE},
615 $self->storage->read_at(
616 $self->trans_loc + $self->txn_bitfield_len + $STALE_SIZE * ($trans_id - 1),
622 sub inc_txn_staleness_counter {
626 # Hardcode staleness of 0 for the HEAD
627 return 0 unless $trans_id;
629 $self->storage->print_at(
630 $self->trans_loc + $self->txn_bitfield_len + $STALE_SIZE * ($trans_id - 1),
631 pack( $StP{$STALE_SIZE}, $self->get_txn_staleness_counter( $trans_id ) + 1 ),
637 return [ keys %{ $self->{entries}{$self->trans_id} ||= {} } ];
642 my ($trans_id, $loc) = @_;
644 $self->{entries}{$trans_id} ||= {};
645 $self->{entries}{$trans_id}{$loc} = undef;
648 # If the buckets are being relocated because of a reindexing, the entries
649 # mechanism needs to be made aware of it.
652 my ($old_loc, $new_loc) = @_;
655 while ( my ($trans_id, $locs) = each %{ $self->{entries} } ) {
656 foreach my $orig_loc ( keys %{ $locs } ) {
657 if ( $orig_loc == $old_loc ) {
658 delete $locs->{orig_loc};
659 $locs->{$new_loc} = undef;
668 delete $self->{entries}{$self->trans_id};
671 ################################################################################
674 my $header_fixed = length( SIG_FILE ) + 1 + 4 + 4;
675 my $this_file_version = 3;
677 sub _write_file_header {
680 my $nt = $self->num_txns;
681 my $bl = $self->txn_bitfield_len;
683 my $header_var = 1 + 1 + 1 + 1 + $bl + $STALE_SIZE * ($nt - 1) + 3 * $self->byte_size;
685 my $loc = $self->storage->request_space( $header_fixed + $header_var );
687 $self->storage->print_at( $loc,
690 pack('N', $this_file_version), # At this point, we're at 9 bytes
691 pack('N', $header_var), # header size
692 # --- Above is $header_fixed. Below is $header_var
693 pack('C', $self->byte_size),
695 # These shenanigans are to allow a 256 within a C
696 pack('C', $self->max_buckets - 1),
697 pack('C', $self->data_sector_size - 1),
700 pack('C' . $bl, 0 ), # Transaction activeness bitfield
701 pack($StP{$STALE_SIZE}.($nt-1), 0 x ($nt-1) ), # Transaction staleness counters
702 pack($StP{$self->byte_size}, 0), # Start of free chain (blist size)
703 pack($StP{$self->byte_size}, 0), # Start of free chain (data size)
704 pack($StP{$self->byte_size}, 0), # Start of free chain (index size)
707 #XXX Set these less fragilely
708 $self->set_trans_loc( $header_fixed + 4 );
709 $self->set_chains_loc( $header_fixed + 4 + $bl + $STALE_SIZE * ($nt-1) );
714 sub _read_file_header {
717 my $buffer = $self->storage->read_at( 0, $header_fixed );
718 return unless length($buffer);
720 my ($file_signature, $sig_header, $file_version, $size) = unpack(
724 unless ( $file_signature eq SIG_FILE ) {
725 $self->storage->close;
726 DBM::Deep->_throw_error( "Signature not found -- file is not a Deep DB" );
729 unless ( $sig_header eq SIG_HEADER ) {
730 $self->storage->close;
731 DBM::Deep->_throw_error( "Pre-1.00 file version found" );
734 unless ( $file_version == $this_file_version ) {
735 $self->storage->close;
736 DBM::Deep->_throw_error(
737 "Wrong file version found - " . $file_version .
738 " - expected " . $this_file_version
742 my $buffer2 = $self->storage->read_at( undef, $size );
743 my @values = unpack( 'C C C C', $buffer2 );
745 if ( @values != 4 || grep { !defined } @values ) {
746 $self->storage->close;
747 DBM::Deep->_throw_error("Corrupted file - bad header");
750 #XXX Add warnings if values weren't set right
751 @{$self}{qw(byte_size max_buckets data_sector_size num_txns)} = @values;
753 # These shenangians are to allow a 256 within a C
754 $self->{max_buckets} += 1;
755 $self->{data_sector_size} += 1;
757 my $bl = $self->txn_bitfield_len;
759 my $header_var = scalar(@values) + $bl + $STALE_SIZE * ($self->num_txns - 1) + 3 * $self->byte_size;
760 unless ( $size == $header_var ) {
761 $self->storage->close;
762 DBM::Deep->_throw_error( "Unexpected size found ($size <-> $header_var)." );
765 $self->set_trans_loc( $header_fixed + scalar(@values) );
766 $self->set_chains_loc( $header_fixed + scalar(@values) + $bl + $STALE_SIZE * ($self->num_txns - 1) );
768 return length($buffer) + length($buffer2);
776 # Add a catch for offset of 0 or 1
777 return if !$offset || $offset <= 1;
779 my $type = $self->storage->read_at( $offset, 1 );
780 return if $type eq chr(0);
782 if ( $type eq $self->SIG_ARRAY || $type eq $self->SIG_HASH ) {
783 return DBM::Deep::Engine::Sector::Reference->new({
789 # XXX Don't we need key_md5 here?
790 elsif ( $type eq $self->SIG_BLIST ) {
791 return DBM::Deep::Engine::Sector::BucketList->new({
797 elsif ( $type eq $self->SIG_INDEX ) {
798 return DBM::Deep::Engine::Sector::Index->new({
804 elsif ( $type eq $self->SIG_NULL ) {
805 return DBM::Deep::Engine::Sector::Null->new({
811 elsif ( $type eq $self->SIG_DATA ) {
812 return DBM::Deep::Engine::Sector::Scalar->new({
818 # This was deleted from under us, so just return and let the caller figure it out.
819 elsif ( $type eq $self->SIG_FREE ) {
823 DBM::Deep->_throw_error( "'$offset': Don't know what to do with type '$type'" );
828 return $self->{digest}->(@_);
831 sub _add_free_blist_sector { shift->_add_free_sector( 0, @_ ) }
832 sub _add_free_data_sector { shift->_add_free_sector( 1, @_ ) }
833 sub _add_free_index_sector { shift->_add_free_sector( 2, @_ ) }
835 sub _add_free_sector {
837 my ($multiple, $offset, $size) = @_;
839 my $chains_offset = $multiple * $self->byte_size;
841 my $storage = $self->storage;
843 # Increment staleness.
844 # XXX Can this increment+modulo be done by "&= 0x1" ?
845 my $staleness = unpack( $StP{$STALE_SIZE}, $storage->read_at( $offset + SIG_SIZE, $STALE_SIZE ) );
846 $staleness = ($staleness + 1 ) % ( 2 ** ( 8 * $STALE_SIZE ) );
847 $storage->print_at( $offset + SIG_SIZE, pack( $StP{$STALE_SIZE}, $staleness ) );
849 my $old_head = $storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
851 $storage->print_at( $self->chains_loc + $chains_offset,
852 pack( $StP{$self->byte_size}, $offset ),
855 # Record the old head in the new sector after the signature and staleness counter
856 $storage->print_at( $offset + SIG_SIZE + $STALE_SIZE, $old_head );
859 sub _request_blist_sector { shift->_request_sector( 0, @_ ) }
860 sub _request_data_sector { shift->_request_sector( 1, @_ ) }
861 sub _request_index_sector { shift->_request_sector( 2, @_ ) }
863 sub _request_sector {
865 my ($multiple, $size) = @_;
867 my $chains_offset = $multiple * $self->byte_size;
869 my $old_head = $self->storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
870 my $loc = unpack( $StP{$self->byte_size}, $old_head );
872 # We don't have any free sectors of the right size, so allocate a new one.
874 my $offset = $self->storage->request_space( $size );
876 # Zero out the new sector. This also guarantees correct increases
878 $self->storage->print_at( $offset, chr(0) x $size );
883 # Read the new head after the signature and the staleness counter
884 my $new_head = $self->storage->read_at( $loc + SIG_SIZE + $STALE_SIZE, $self->byte_size );
885 $self->storage->print_at( $self->chains_loc + $chains_offset, $new_head );
886 $self->storage->print_at(
887 $loc + SIG_SIZE + $STALE_SIZE,
888 pack( $StP{$self->byte_size}, 0 ),
894 ################################################################################
896 sub storage { $_[0]{storage} }
897 sub byte_size { $_[0]{byte_size} }
898 sub hash_size { $_[0]{hash_size} }
899 sub hash_chars { $_[0]{hash_chars} }
900 sub num_txns { $_[0]{num_txns} }
901 sub max_buckets { $_[0]{max_buckets} }
902 sub blank_md5 { chr(0) x $_[0]->hash_size }
903 sub data_sector_size { $_[0]{data_sector_size} }
905 # This is a calculated value
906 sub txn_bitfield_len {
908 unless ( exists $self->{txn_bitfield_len} ) {
909 my $temp = ($self->num_txns) / 8;
910 if ( $temp > int( $temp ) ) {
911 $temp = int( $temp ) + 1;
913 $self->{txn_bitfield_len} = $temp;
915 return $self->{txn_bitfield_len};
918 sub trans_id { $_[0]{trans_id} }
919 sub set_trans_id { $_[0]{trans_id} = $_[1] }
921 sub trans_loc { $_[0]{trans_loc} }
922 sub set_trans_loc { $_[0]{trans_loc} = $_[1] }
924 sub chains_loc { $_[0]{chains_loc} }
925 sub set_chains_loc { $_[0]{chains_loc} = $_[1] }
927 sub cache { $_[0]{cache} ||= {} }
928 sub clear_cache { %{$_[0]->cache} = () }
934 my $spot = $self->_read_file_header();
943 'D' => $self->data_sector_size,
944 'B' => DBM::Deep::Engine::Sector::BucketList->new({engine=>$self,offset=>1})->size,
945 'I' => DBM::Deep::Engine::Sector::Index->new({engine=>$self,offset=>1})->size,
951 $return .= "NumTxns: " . $self->num_txns . $/;
953 # Read the free sector chains
955 foreach my $multiple ( 0 .. 2 ) {
956 $return .= "Chains($types{$multiple}):";
957 my $old_loc = $self->chains_loc + $multiple * $self->byte_size;
960 $StP{$self->byte_size},
961 $self->storage->read_at( $old_loc, $self->byte_size ),
964 # We're now out of free sectors of this kind.
969 $sectors{ $types{$multiple} }{ $loc } = undef;
970 $old_loc = $loc + SIG_SIZE + $STALE_SIZE;
977 while ( $spot < $self->storage->{end} ) {
978 # Read each sector in order.
979 my $sector = $self->_load_sector( $spot );
981 # Find it in the free-sectors that were found already
982 foreach my $type ( keys %sectors ) {
983 if ( exists $sectors{$type}{$spot} ) {
984 my $size = $sizes{$type};
985 $return .= sprintf "%08d: %s %04d\n", $spot, 'F' . $type, $size;
991 die "********\n$return\nDidn't find free sector for $spot in chains\n********\n";
994 $return .= sprintf "%08d: %s %04d", $spot, $sector->type, $sector->size;
995 if ( $sector->type eq 'D' ) {
996 $return .= ' ' . $sector->data;
998 elsif ( $sector->type eq 'A' || $sector->type eq 'H' ) {
999 $return .= ' REF: ' . $sector->get_refcount;
1001 elsif ( $sector->type eq 'B' ) {
1002 foreach my $bucket ( $sector->chopped_up ) {
1004 $return .= sprintf "%08d", unpack($StP{$self->byte_size},
1005 substr( $bucket->[-1], $self->hash_size, $self->byte_size),
1007 my $l = unpack( $StP{$self->byte_size},
1008 substr( $bucket->[-1],
1009 $self->hash_size + $self->byte_size,
1013 $return .= sprintf " %08d", $l;
1014 foreach my $txn ( 0 .. $self->num_txns - 2 ) {
1015 my $l = unpack( $StP{$self->byte_size},
1016 substr( $bucket->[-1],
1017 $self->hash_size + 2 * $self->byte_size + $txn * ($self->byte_size + $STALE_SIZE),
1021 $return .= sprintf " %08d", $l;
1027 $spot += $sector->size;
1034 ################################################################################
1036 package DBM::Deep::Iterator;
1044 engine => $args->{engine},
1045 base_offset => $args->{base_offset},
1048 Scalar::Util::weaken( $self->{engine} );
1053 sub reset { $_[0]{breadcrumbs} = [] }
1055 sub get_sector_iterator {
1059 my $sector = $self->{engine}->_load_sector( $loc )
1062 if ( $sector->isa( 'DBM::Deep::Engine::Sector::Index' ) ) {
1063 return DBM::Deep::Iterator::Index->new({
1068 elsif ( $sector->isa( 'DBM::Deep::Engine::Sector::BucketList' ) ) {
1069 return DBM::Deep::Iterator::BucketList->new({
1075 DBM::Deep->_throw_error( "get_sector_iterator(): Why did $loc make a $sector?" );
1082 my $crumbs = $self->{breadcrumbs};
1083 my $e = $self->{engine};
1085 unless ( @$crumbs ) {
1086 # This will be a Reference sector
1087 my $sector = $e->_load_sector( $self->{base_offset} )
1088 # If no sector is found, thist must have been deleted from under us.
1091 if ( $sector->staleness != $obj->_staleness ) {
1095 my $loc = $sector->get_blist_loc
1098 push @$crumbs, $self->get_sector_iterator( $loc );
1103 unless ( @$crumbs ) {
1108 my $iterator = $crumbs->[-1];
1110 # This level is done.
1111 if ( $iterator->at_end ) {
1116 if ( $iterator->isa( 'DBM::Deep::Iterator::Index' ) ) {
1117 # If we don't have any more, it will be caught at the
1119 if ( my $next = $iterator->get_next_iterator ) {
1120 push @$crumbs, $next;
1125 unless ( $iterator->isa( 'DBM::Deep::Iterator::BucketList' ) ) {
1126 DBM::Deep->_throw_error(
1127 "Should have a bucketlist iterator here - instead have $iterator"
1131 # At this point, we have a BucketList iterator
1132 my $key = $iterator->get_next_key;
1133 if ( defined $key ) {
1136 #XXX else { $iterator->set_to_end() } ?
1138 # We hit the end of the bucketlist iterator, so redo
1142 DBM::Deep->_throw_error( "get_next_key(): How did we get here?" );
1145 package DBM::Deep::Iterator::Index;
1148 my $self = bless $_[1] => $_[0];
1149 $self->{curr_index} = 0;
1155 return $self->{curr_index} >= $self->{iterator}{engine}->hash_chars;
1158 sub get_next_iterator {
1163 return if $self->at_end;
1164 $loc = $self->{sector}->get_entry( $self->{curr_index}++ );
1167 return $self->{iterator}->get_sector_iterator( $loc );
1170 package DBM::Deep::Iterator::BucketList;
1173 my $self = bless $_[1] => $_[0];
1174 $self->{curr_index} = 0;
1180 return $self->{curr_index} >= $self->{iterator}{engine}->max_buckets;
1186 return if $self->at_end;
1188 my $idx = $self->{curr_index}++;
1190 my $data_loc = $self->{sector}->get_data_location_for({
1195 #XXX Do we want to add corruption checks here?
1196 return $self->{sector}->get_key_for( $idx )->data;
1199 package DBM::Deep::Engine::Sector;
1202 my $self = bless $_[1], $_[0];
1203 Scalar::Util::weaken( $self->{engine} );
1209 #sub clone { DBM::Deep->_throw_error( "Must be implemented in the child class" ); }
1211 sub engine { $_[0]{engine} }
1212 sub offset { $_[0]{offset} }
1213 sub type { $_[0]{type} }
1217 return $self->engine->SIG_SIZE + $STALE_SIZE;
1223 my $e = $self->engine;
1225 $e->storage->print_at( $self->offset, $e->SIG_FREE );
1226 # Skip staleness counter
1227 $e->storage->print_at( $self->offset + $self->base_size,
1228 chr(0) x ($self->size - $self->base_size),
1231 my $free_meth = $self->free_meth;
1232 $e->$free_meth( $self->offset, $self->size );
1237 package DBM::Deep::Engine::Sector::Data;
1239 our @ISA = qw( DBM::Deep::Engine::Sector );
1242 sub size { $_[0]{engine}->data_sector_size }
1243 sub free_meth { return '_add_free_data_sector' }
1247 return ref($self)->new({
1248 engine => $self->engine,
1249 type => $self->type,
1250 data => $self->data,
1254 package DBM::Deep::Engine::Sector::Scalar;
1256 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1261 my $chain_loc = $self->chain_loc;
1263 $self->SUPER::free();
1266 $self->engine->_load_sector( $chain_loc )->free;
1272 sub type { $_[0]{engine}->SIG_DATA }
1276 my $engine = $self->engine;
1278 unless ( $self->offset ) {
1279 my $data_section = $self->size - $self->base_size - $engine->byte_size - 1;
1281 $self->{offset} = $engine->_request_data_sector( $self->size );
1283 my $data = delete $self->{data};
1284 my $dlen = length $data;
1286 my $curr_offset = $self->offset;
1287 while ( $continue ) {
1289 my $next_offset = 0;
1291 my ($leftover, $this_len, $chunk);
1292 if ( $dlen > $data_section ) {
1294 $this_len = $data_section;
1295 $chunk = substr( $data, 0, $this_len );
1297 $dlen -= $data_section;
1298 $next_offset = $engine->_request_data_sector( $self->size );
1299 $data = substr( $data, $this_len );
1302 $leftover = $data_section - $dlen;
1309 $engine->storage->print_at( $curr_offset, $self->type ); # Sector type
1311 $engine->storage->print_at( $curr_offset + $self->base_size,
1312 pack( $StP{$engine->byte_size}, $next_offset ), # Chain loc
1313 pack( $StP{1}, $this_len ), # Data length
1314 $chunk, # Data to be stored in this sector
1315 chr(0) x $leftover, # Zero-fill the rest
1318 $curr_offset = $next_offset;
1328 my $buffer = $self->engine->storage->read_at(
1329 $self->offset + $self->base_size + $self->engine->byte_size, 1
1332 return unpack( $StP{1}, $buffer );
1338 $StP{$self->engine->byte_size},
1339 $self->engine->storage->read_at(
1340 $self->offset + $self->base_size,
1341 $self->engine->byte_size,
1351 my $chain_loc = $self->chain_loc;
1353 $data .= $self->engine->storage->read_at(
1354 $self->offset + $self->base_size + $self->engine->byte_size + 1, $self->data_length,
1357 last unless $chain_loc;
1359 $self = $self->engine->_load_sector( $chain_loc );
1365 package DBM::Deep::Engine::Sector::Null;
1367 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1369 sub type { $_[0]{engine}->SIG_NULL }
1370 sub data_length { 0 }
1376 my $engine = $self->engine;
1378 unless ( $self->offset ) {
1379 my $leftover = $self->size - $self->base_size - 1 * $engine->byte_size - 1;
1381 $self->{offset} = $engine->_request_data_sector( $self->size );
1382 $engine->storage->print_at( $self->offset, $self->type ); # Sector type
1383 # Skip staleness counter
1384 $engine->storage->print_at( $self->offset + $self->base_size,
1385 pack( $StP{$engine->byte_size}, 0 ), # Chain loc
1386 pack( $StP{1}, $self->data_length ), # Data length
1387 chr(0) x $leftover, # Zero-fill the rest
1394 package DBM::Deep::Engine::Sector::Reference;
1396 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1401 my $e = $self->engine;
1403 unless ( $self->offset ) {
1404 my $classname = Scalar::Util::blessed( delete $self->{data} );
1405 my $leftover = $self->size - $self->base_size - 3 * $e->byte_size;
1407 my $class_offset = 0;
1408 if ( defined $classname ) {
1409 my $class_sector = DBM::Deep::Engine::Sector::Scalar->new({
1413 $class_offset = $class_sector->offset;
1416 $self->{offset} = $e->_request_data_sector( $self->size );
1417 $e->storage->print_at( $self->offset, $self->type ); # Sector type
1418 # Skip staleness counter
1419 $e->storage->print_at( $self->offset + $self->base_size,
1420 pack( $StP{$e->byte_size}, 0 ), # Index/BList loc
1421 pack( $StP{$e->byte_size}, $class_offset ), # Classname loc
1422 pack( $StP{$e->byte_size}, 1 ), # Initial refcount
1423 chr(0) x $leftover, # Zero-fill the rest
1427 $self->{type} = $e->storage->read_at( $self->offset, 1 );
1430 $self->{staleness} = unpack(
1432 $e->storage->read_at( $self->offset + $e->SIG_SIZE, $STALE_SIZE ),
1438 sub staleness { $_[0]{staleness} }
1444 # Assume that the head is not allowed unless otherwise specified.
1445 $args->{allow_head} = 0 unless exists $args->{allow_head};
1447 # Assume we don't create a new blist location unless otherwise specified.
1448 $args->{create} = 0 unless exists $args->{create};
1450 my $blist = $self->get_bucket_list({
1451 key_md5 => $args->{key_md5},
1452 key => $args->{key},
1453 create => $args->{create},
1455 return unless $blist && $blist->{found};
1457 # At this point, $blist knows where the md5 is. What it -doesn't- know yet
1458 # is whether or not this transaction has this key. That's part of the next
1460 my $location = $blist->get_data_location_for({
1461 allow_head => $args->{allow_head},
1464 return $self->engine->_load_sector( $location );
1471 my $blist = $self->get_bucket_list({
1472 key_md5 => $args->{key_md5},
1473 key => $args->{key},
1475 }) or DBM::Deep->_throw_error( "How did write_data fail (no blist)?!" );
1477 # Handle any transactional bookkeeping.
1478 if ( $self->engine->trans_id ) {
1479 if ( ! $blist->has_md5 ) {
1480 $blist->mark_deleted({
1486 my @trans_ids = $self->engine->get_running_txn_ids;
1487 if ( $blist->has_md5 ) {
1489 my $old_value = $blist->get_data_for;
1490 foreach my $other_trans_id ( @trans_ids ) {
1491 next if $blist->get_data_location_for({
1492 trans_id => $other_trans_id,
1496 trans_id => $other_trans_id,
1497 key => $args->{key},
1498 key_md5 => $args->{key_md5},
1499 value => $old_value->clone,
1506 foreach my $other_trans_id ( @trans_ids ) {
1507 #XXX This doesn't seem to possible to ever happen . . .
1508 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1509 $blist->mark_deleted({
1510 trans_id => $other_trans_id,
1517 #XXX Is this safe to do transactionally?
1518 # Free the place we're about to write to.
1519 if ( $blist->get_data_location_for({ allow_head => 0 }) ) {
1520 $blist->get_data_for({ allow_head => 0 })->free;
1524 key => $args->{key},
1525 key_md5 => $args->{key_md5},
1526 value => $args->{value},
1534 # XXX What should happen if this fails?
1535 my $blist = $self->get_bucket_list({
1536 key_md5 => $args->{key_md5},
1537 }) or DBM::Deep->_throw_error( "How did delete_key fail (no blist)?!" );
1539 # Save the location so that we can free the data
1540 my $location = $blist->get_data_location_for({
1543 my $old_value = $location && $self->engine->_load_sector( $location );
1545 my @trans_ids = $self->engine->get_running_txn_ids;
1547 # If we're the HEAD and there are running txns, then we need to clone this value to the other
1548 # transactions to preserve Isolation.
1549 if ( $self->engine->trans_id == 0 ) {
1551 foreach my $other_trans_id ( @trans_ids ) {
1552 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1554 trans_id => $other_trans_id,
1555 key => $args->{key},
1556 key_md5 => $args->{key_md5},
1557 value => $old_value->clone,
1565 $blist->mark_deleted( $args );
1568 $data = $old_value->data;
1573 $data = $blist->delete_md5( $args );
1582 my $e = $self->engine;
1583 my $blist_loc = $e->storage->read_at( $self->offset + $self->base_size, $e->byte_size );
1584 return unpack( $StP{$e->byte_size}, $blist_loc );
1587 sub get_bucket_list {
1592 # XXX Add in check here for recycling?
1594 my $engine = $self->engine;
1596 my $blist_loc = $self->get_blist_loc;
1598 # There's no index or blist yet
1599 unless ( $blist_loc ) {
1600 return unless $args->{create};
1602 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1604 key_md5 => $args->{key_md5},
1607 $engine->storage->print_at( $self->offset + $self->base_size,
1608 pack( $StP{$engine->byte_size}, $blist->offset ),
1614 my $sector = $engine->_load_sector( $blist_loc )
1615 or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
1617 my $last_sector = undef;
1618 while ( $sector->isa( 'DBM::Deep::Engine::Sector::Index' ) ) {
1619 $blist_loc = $sector->get_entry( ord( substr( $args->{key_md5}, $i++, 1 ) ) );
1620 $last_sector = $sector;
1622 $sector = $engine->_load_sector( $blist_loc )
1623 or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
1631 # This means we went through the Index sector(s) and found an empty slot
1632 unless ( $sector ) {
1633 return unless $args->{create};
1635 DBM::Deep->_throw_error( "No last_sector when attempting to build a new entry" )
1636 unless $last_sector;
1638 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1640 key_md5 => $args->{key_md5},
1643 $last_sector->set_entry( ord( substr( $args->{key_md5}, $i - 1, 1 ) ) => $blist->offset );
1648 $sector->find_md5( $args->{key_md5} );
1650 # See whether or not we need to reindex the bucketlist
1651 # Yes, the double-braces are there for a reason. if() doesn't create a redo-able block,
1652 # so we have to create a bare block within the if() for redo-purposes. Patch and idea
1653 # submitted by sprout@cpan.org. -RobK, 2008-01-09
1654 if ( !$sector->has_md5 && $args->{create} && $sector->{idx} == -1 ) {{
1657 my $new_index = DBM::Deep::Engine::Sector::Index->new({
1662 #XXX q.v. the comments for this function.
1663 foreach my $entry ( $sector->chopped_up ) {
1664 my ($spot, $md5) = @{$entry};
1665 my $idx = ord( substr( $md5, $i, 1 ) );
1667 # XXX This is inefficient
1668 my $blist = $blist_cache{$idx}
1669 ||= DBM::Deep::Engine::Sector::BucketList->new({
1673 $new_index->set_entry( $idx => $blist->offset );
1675 my $new_spot = $blist->write_at_next_open( $md5 );
1676 $engine->reindex_entry( $spot => $new_spot );
1679 # Handle the new item separately.
1681 my $idx = ord( substr( $args->{key_md5}, $i, 1 ) );
1683 # If all the previous blist's items have been thrown into one
1684 # blist and the new item belongs in there too, we need
1686 if ( keys %blist_cache == 1 and each %blist_cache == $idx ) {
1689 my $blist = $blist_cache{$idx}
1690 ||= DBM::Deep::Engine::Sector::BucketList->new({
1694 $new_index->set_entry( $idx => $blist->offset );
1697 $blist->find_md5( $args->{key_md5} );
1699 key => $args->{key},
1700 key_md5 => $args->{key_md5},
1701 value => DBM::Deep::Engine::Sector::Null->new({
1707 # my $blist = $blist_cache{$idx}
1708 # ||= DBM::Deep::Engine::Sector::BucketList->new({
1709 # engine => $engine,
1712 # $new_index->set_entry( $idx => $blist->offset );
1714 # #XXX THIS IS HACKY!
1715 # $blist->find_md5( $args->{key_md5} );
1716 # $blist->write_md5({
1717 # key => $args->{key},
1718 # key_md5 => $args->{key_md5},
1719 # value => DBM::Deep::Engine::Sector::Null->new({
1720 # engine => $engine,
1726 if ( $last_sector ) {
1727 $last_sector->set_entry(
1728 ord( substr( $args->{key_md5}, $i - 1, 1 ) ),
1732 $engine->storage->print_at( $self->offset + $self->base_size,
1733 pack( $StP{$engine->byte_size}, $new_index->offset ),
1741 (undef, $sector) = %blist_cache;
1742 $last_sector = $new_index;
1746 $sector = $blist_cache{ ord( substr( $args->{key_md5}, $i, 1 ) ) };
1747 $sector->find_md5( $args->{key_md5} );
1753 sub get_class_offset {
1756 my $e = $self->engine;
1758 $StP{$e->byte_size},
1759 $e->storage->read_at(
1760 $self->offset + $self->base_size + 1 * $e->byte_size, $e->byte_size,
1768 my $class_offset = $self->get_class_offset;
1770 return unless $class_offset;
1772 return $self->engine->_load_sector( $class_offset )->data;
1778 unless ( $self->engine->cache->{ $self->offset } ) {
1779 my $new_obj = DBM::Deep->new({
1780 type => $self->type,
1781 base_offset => $self->offset,
1782 staleness => $self->staleness,
1783 storage => $self->engine->storage,
1784 engine => $self->engine,
1787 if ( $self->engine->storage->{autobless} ) {
1788 my $classname = $self->get_classname;
1789 if ( defined $classname ) {
1790 bless $new_obj, $classname;
1794 $self->engine->cache->{$self->offset} = $new_obj;
1796 return $self->engine->cache->{$self->offset};
1802 # We're not ready to be removed yet.
1803 if ( $self->decrement_refcount > 0 ) {
1807 # Rebless the object into DBM::Deep::Null.
1808 eval { %{ $self->engine->cache->{ $self->offset } } = (); };
1809 eval { @{ $self->engine->cache->{ $self->offset } } = (); };
1810 bless $self->engine->cache->{ $self->offset }, 'DBM::Deep::Null';
1811 delete $self->engine->cache->{ $self->offset };
1813 my $blist_loc = $self->get_blist_loc;
1814 $self->engine->_load_sector( $blist_loc )->free if $blist_loc;
1816 my $class_loc = $self->get_class_offset;
1817 $self->engine->_load_sector( $class_loc )->free if $class_loc;
1819 $self->SUPER::free();
1822 sub increment_refcount {
1825 my $refcount = $self->get_refcount;
1829 $self->write_refcount( $refcount );
1834 sub decrement_refcount {
1837 my $refcount = $self->get_refcount;
1841 $self->write_refcount( $refcount );
1849 my $e = $self->engine;
1851 $StP{$e->byte_size},
1852 $e->storage->read_at(
1853 $self->offset + $self->base_size + 2 * $e->byte_size, $e->byte_size,
1858 sub write_refcount {
1862 my $e = $self->engine;
1863 $e->storage->print_at(
1864 $self->offset + $self->base_size + 2 * $e->byte_size,
1865 pack( $StP{$e->byte_size}, $num ),
1869 package DBM::Deep::Engine::Sector::BucketList;
1871 our @ISA = qw( DBM::Deep::Engine::Sector );
1876 my $engine = $self->engine;
1878 unless ( $self->offset ) {
1879 my $leftover = $self->size - $self->base_size;
1881 $self->{offset} = $engine->_request_blist_sector( $self->size );
1882 $engine->storage->print_at( $self->offset, $engine->SIG_BLIST ); # Sector type
1883 # Skip staleness counter
1884 $engine->storage->print_at( $self->offset + $self->base_size,
1885 chr(0) x $leftover, # Zero-fill the data
1889 if ( $self->{key_md5} ) {
1898 $self->engine->storage->print_at( $self->offset + $self->base_size,
1899 chr(0) x ($self->size - $self->base_size), # Zero-fill the data
1905 unless ( $self->{size} ) {
1906 my $e = $self->engine;
1907 # Base + numbuckets * bucketsize
1908 $self->{size} = $self->base_size + $e->max_buckets * $self->bucket_size;
1910 return $self->{size};
1913 sub free_meth { return '_add_free_blist_sector' }
1918 my $e = $self->engine;
1919 foreach my $bucket ( $self->chopped_up ) {
1920 my $rest = $bucket->[-1];
1922 # Delete the keysector
1923 my $l = unpack( $StP{$e->byte_size}, substr( $rest, $e->hash_size, $e->byte_size ) );
1924 my $s = $e->_load_sector( $l ); $s->free if $s;
1926 # Delete the HEAD sector
1927 $l = unpack( $StP{$e->byte_size},
1929 $e->hash_size + $e->byte_size,
1933 $s = $e->_load_sector( $l ); $s->free if $s;
1935 foreach my $txn ( 0 .. $e->num_txns - 2 ) {
1936 my $l = unpack( $StP{$e->byte_size},
1938 $e->hash_size + 2 * $e->byte_size + $txn * ($e->byte_size + $STALE_SIZE),
1942 my $s = $e->_load_sector( $l ); $s->free if $s;
1946 $self->SUPER::free();
1951 unless ( $self->{bucket_size} ) {
1952 my $e = $self->engine;
1953 # Key + head (location) + transactions (location + staleness-counter)
1954 my $location_size = $e->byte_size + $e->byte_size + ($e->num_txns - 1) * ($e->byte_size + $STALE_SIZE);
1955 $self->{bucket_size} = $e->hash_size + $location_size;
1957 return $self->{bucket_size};
1960 # XXX This is such a poor hack. I need to rethink this code.
1964 my $e = $self->engine;
1967 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
1968 my $spot = $self->offset + $self->base_size + $idx * $self->bucket_size;
1969 my $md5 = $e->storage->read_at( $spot, $e->hash_size );
1971 #XXX If we're chopping, why would we ever have the blank_md5?
1972 last if $md5 eq $e->blank_md5;
1974 my $rest = $e->storage->read_at( undef, $self->bucket_size - $e->hash_size );
1975 push @buckets, [ $spot, $md5 . $rest ];
1981 sub write_at_next_open {
1985 #XXX This is such a hack!
1986 $self->{_next_open} = 0 unless exists $self->{_next_open};
1988 my $spot = $self->offset + $self->base_size + $self->{_next_open}++ * $self->bucket_size;
1989 $self->engine->storage->print_at( $spot, $entry );
1996 unless ( exists $self->{found} ) {
1999 return $self->{found};
2005 $self->{found} = undef;
2009 $self->{key_md5} = shift;
2012 # If we don't have an MD5, then what are we supposed to do?
2013 unless ( exists $self->{key_md5} ) {
2014 DBM::Deep->_throw_error( "Cannot find_md5 without a key_md5 set" );
2017 my $e = $self->engine;
2018 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
2019 my $potential = $e->storage->read_at(
2020 $self->offset + $self->base_size + $idx * $self->bucket_size, $e->hash_size,
2023 if ( $potential eq $e->blank_md5 ) {
2024 $self->{idx} = $idx;
2028 if ( $potential eq $self->{key_md5} ) {
2030 $self->{idx} = $idx;
2042 DBM::Deep->_throw_error( "write_md5: no key" ) unless exists $args->{key};
2043 DBM::Deep->_throw_error( "write_md5: no key_md5" ) unless exists $args->{key_md5};
2044 DBM::Deep->_throw_error( "write_md5: no value" ) unless exists $args->{value};
2046 my $engine = $self->engine;
2048 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
2050 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
2051 $engine->add_entry( $args->{trans_id}, $spot );
2053 unless ($self->{found}) {
2054 my $key_sector = DBM::Deep::Engine::Sector::Scalar->new({
2056 data => $args->{key},
2059 $engine->storage->print_at( $spot,
2061 pack( $StP{$engine->byte_size}, $key_sector->offset ),
2066 + $engine->hash_size
2067 + $engine->byte_size;
2069 if ( $args->{trans_id} ) {
2070 $loc += $engine->byte_size + ($args->{trans_id} - 1) * ( $engine->byte_size + $STALE_SIZE );
2072 $engine->storage->print_at( $loc,
2073 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
2074 pack( $StP{$STALE_SIZE}, $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
2078 $engine->storage->print_at( $loc,
2079 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
2089 my $engine = $self->engine;
2091 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
2093 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
2094 $engine->add_entry( $args->{trans_id}, $spot );
2097 + $engine->hash_size
2098 + $engine->byte_size;
2100 if ( $args->{trans_id} ) {
2101 $loc += $engine->byte_size + ($args->{trans_id} - 1) * ( $engine->byte_size + $STALE_SIZE );
2103 $engine->storage->print_at( $loc,
2104 pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
2105 pack( $StP{$STALE_SIZE}, $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
2109 $engine->storage->print_at( $loc,
2110 pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
2120 my $engine = $self->engine;
2121 return undef unless $self->{found};
2123 # Save the location so that we can free the data
2124 my $location = $self->get_data_location_for({
2127 my $key_sector = $self->get_key_for;
2129 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
2130 $engine->storage->print_at( $spot,
2131 $engine->storage->read_at(
2132 $spot + $self->bucket_size,
2133 $self->bucket_size * ( $engine->max_buckets - $self->{idx} - 1 ),
2135 chr(0) x $self->bucket_size,
2140 my $data_sector = $self->engine->_load_sector( $location );
2141 my $data = $data_sector->data;
2147 sub get_data_location_for {
2152 $args->{allow_head} = 0 unless exists $args->{allow_head};
2153 $args->{trans_id} = $self->engine->trans_id unless exists $args->{trans_id};
2154 $args->{idx} = $self->{idx} unless exists $args->{idx};
2156 my $e = $self->engine;
2158 my $spot = $self->offset + $self->base_size
2159 + $args->{idx} * $self->bucket_size
2163 if ( $args->{trans_id} ) {
2164 $spot += $e->byte_size + ($args->{trans_id} - 1) * ( $e->byte_size + $STALE_SIZE );
2167 my $buffer = $e->storage->read_at(
2169 $e->byte_size + $STALE_SIZE,
2171 my ($loc, $staleness) = unpack( $StP{$e->byte_size} . ' ' . $StP{$STALE_SIZE}, $buffer );
2173 # XXX Merge the two if-clauses below
2174 if ( $args->{trans_id} ) {
2175 # We have found an entry that is old, so get rid of it
2176 if ( $staleness != (my $s = $e->get_txn_staleness_counter( $args->{trans_id} ) ) ) {
2177 $e->storage->print_at(
2179 pack( $StP{$e->byte_size} . ' ' . $StP{$STALE_SIZE}, (0) x 2 ),
2185 # If we're in a transaction and we never wrote to this location, try the
2187 if ( $args->{trans_id} && !$loc && $args->{allow_head} ) {
2188 return $self->get_data_location_for({
2191 idx => $args->{idx},
2195 return $loc <= 1 ? 0 : $loc;
2203 return unless $self->{found};
2204 my $location = $self->get_data_location_for({
2205 allow_head => $args->{allow_head},
2207 return $self->engine->_load_sector( $location );
2213 $idx = $self->{idx} unless defined $idx;
2215 if ( $idx >= $self->engine->max_buckets ) {
2216 DBM::Deep->_throw_error( "get_key_for(): Attempting to retrieve $idx" );
2219 my $location = $self->engine->storage->read_at(
2220 $self->offset + $self->base_size + $idx * $self->bucket_size + $self->engine->hash_size,
2221 $self->engine->byte_size,
2223 $location = unpack( $StP{$self->engine->byte_size}, $location );
2224 DBM::Deep->_throw_error( "get_key_for: No location?" ) unless $location;
2226 return $self->engine->_load_sector( $location );
2229 package DBM::Deep::Engine::Sector::Index;
2231 our @ISA = qw( DBM::Deep::Engine::Sector );
2236 my $engine = $self->engine;
2238 unless ( $self->offset ) {
2239 my $leftover = $self->size - $self->base_size;
2241 $self->{offset} = $engine->_request_index_sector( $self->size );
2242 $engine->storage->print_at( $self->offset, $engine->SIG_INDEX ); # Sector type
2243 # Skip staleness counter
2244 $engine->storage->print_at( $self->offset + $self->base_size,
2245 chr(0) x $leftover, # Zero-fill the rest
2255 unless ( $self->{size} ) {
2256 my $e = $self->engine;
2257 $self->{size} = $self->base_size + $e->byte_size * $e->hash_chars;
2259 return $self->{size};
2262 sub free_meth { return '_add_free_index_sector' }
2266 my $e = $self->engine;
2268 for my $i ( 0 .. $e->hash_chars - 1 ) {
2269 my $l = $self->get_entry( $i ) or next;
2270 $e->_load_sector( $l )->free;
2273 $self->SUPER::free();
2279 return $self->offset + $self->base_size + $idx * $self->engine->byte_size;
2286 my $e = $self->engine;
2288 DBM::Deep->_throw_error( "get_entry: Out of range ($idx)" )
2289 if $idx < 0 || $idx >= $e->hash_chars;
2292 $StP{$e->byte_size},
2293 $e->storage->read_at( $self->_loc_for( $idx ), $e->byte_size ),
2299 my ($idx, $loc) = @_;
2301 my $e = $self->engine;
2303 DBM::Deep->_throw_error( "set_entry: Out of range ($idx)" )
2304 if $idx < 0 || $idx >= $e->hash_chars;
2306 $self->engine->storage->print_at(
2307 $self->_loc_for( $idx ),
2308 pack( $StP{$e->byte_size}, $loc ),
2312 # This was copied from MARCEL's Class::Null. However, I couldn't use it because
2313 # I need an undef value, not an implementation of the Null Class pattern.
2314 package DBM::Deep::Null;
2317 'bool' => sub { undef },
2318 '""' => sub { undef },
2319 '0+' => sub { undef },
2321 nomethod => 'AUTOLOAD';
2323 sub AUTOLOAD { return; }