1 package DBM::Deep::Engine;
8 our $VERSION = q(1.0013);
10 # Never import symbols into our namespace. We are a class, not a library.
17 # * Every method in here assumes that the storage has been appropriately
18 # safeguarded. This can be anything from flock() to some sort of manual
19 # mutex. But, it's the caller's responsability to make sure that this has
22 # Setup file and tag signatures. These should never change.
23 sub SIG_FILE () { 'DPDB' }
24 sub SIG_HEADER () { 'h' }
25 sub SIG_HASH () { 'H' }
26 sub SIG_ARRAY () { 'A' }
27 sub SIG_NULL () { 'N' }
28 sub SIG_DATA () { 'D' }
29 sub SIG_INDEX () { 'I' }
30 sub SIG_BLIST () { 'B' }
31 sub SIG_FREE () { 'F' }
36 # Please refer to the pack() documentation for further information
38 1 => 'C', # Unsigned char value (no order needed as it's just one byte)
39 2 => 'n', # Unsigned short in "network" (big-endian) order
40 4 => 'N', # Unsigned long in "network" (big-endian) order
41 8 => 'Q', # Usigned quad (no order specified, presumably machine-dependent)
44 ################################################################################
54 hash_size => 16, # In bytes
55 hash_chars => 256, # Number of chars the algorithm uses per byte
57 num_txns => 1, # The HEAD
58 trans_id => 0, # Default to the HEAD
60 data_sector_size => 64, # Size in bytes of each data sector
62 entries => {}, # This is the list of entries for transactions
66 # Never allow byte_size to be set directly.
67 delete $args->{byte_size};
68 if ( defined $args->{pack_size} ) {
69 if ( lc $args->{pack_size} eq 'small' ) {
70 $args->{byte_size} = 2;
72 elsif ( lc $args->{pack_size} eq 'medium' ) {
73 $args->{byte_size} = 4;
75 elsif ( lc $args->{pack_size} eq 'large' ) {
76 $args->{byte_size} = 8;
79 DBM::Deep->_throw_error( "Unknown pack_size value: '$args->{pack_size}'" );
83 # Grab the parameters we want to use
84 foreach my $param ( keys %$self ) {
85 next unless exists $args->{$param};
86 $self->{$param} = $args->{$param};
90 max_buckets => { floor => 16, ceil => 256 },
91 num_txns => { floor => 1, ceil => 255 },
92 data_sector_size => { floor => 32, ceil => 256 },
95 while ( my ($attr, $c) = each %validations ) {
96 if ( !defined $self->{$attr}
97 || !length $self->{$attr}
98 || $self->{$attr} =~ /\D/
99 || $self->{$attr} < $c->{floor}
101 $self->{$attr} = '(undef)' if !defined $self->{$attr};
102 warn "Floor of $attr is $c->{floor}. Setting it to $c->{floor} from '$self->{$attr}'\n";
103 $self->{$attr} = $c->{floor};
105 elsif ( $self->{$attr} > $c->{ceil} ) {
106 warn "Ceiling of $attr is $c->{ceil}. Setting it to $c->{ceil} from '$self->{$attr}'\n";
107 $self->{$attr} = $c->{ceil};
111 if ( !$self->{digest} ) {
113 $self->{digest} = \&Digest::MD5::md5;
119 ################################################################################
123 my ($obj, $key) = @_;
125 # This will be a Reference sector
126 my $sector = $self->_load_sector( $obj->_base_offset )
129 if ( $sector->staleness != $obj->_staleness ) {
133 my $key_md5 = $self->_apply_digest( $key );
135 my $value_sector = $sector->get_data_for({
140 unless ( $value_sector ) {
141 $value_sector = DBM::Deep::Engine::Sector::Null->new({
146 $sector->write_data({
149 value => $value_sector,
153 return $value_sector->data;
160 # This will be a Reference sector
161 my $sector = $self->_load_sector( $obj->_base_offset )
162 or DBM::Deep->_throw_error( "How did get_classname fail (no sector for '$obj')?!" );
164 if ( $sector->staleness != $obj->_staleness ) {
168 return $sector->get_classname;
173 my ($obj, $old_key, $new_key) = @_;
175 # This will be a Reference sector
176 my $sector = $self->_load_sector( $obj->_base_offset )
177 or DBM::Deep->_throw_error( "How did get_classname fail (no sector for '$obj')?!" );
179 if ( $sector->staleness != $obj->_staleness ) {
183 my $old_md5 = $self->_apply_digest( $old_key );
185 my $value_sector = $sector->get_data_for({
190 unless ( $value_sector ) {
191 $value_sector = DBM::Deep::Engine::Sector::Null->new({
196 $sector->write_data({
199 value => $value_sector,
203 if ( $value_sector->isa( 'DBM::Deep::Engine::Sector::Reference' ) ) {
204 $sector->write_data({
206 key_md5 => $self->_apply_digest( $new_key ),
207 value => $value_sector,
209 $value_sector->increment_refcount;
212 $sector->write_data({
214 key_md5 => $self->_apply_digest( $new_key ),
215 value => $value_sector->clone,
222 my ($obj, $key) = @_;
224 # This will be a Reference sector
225 my $sector = $self->_load_sector( $obj->_base_offset )
228 if ( $sector->staleness != $obj->_staleness ) {
232 my $data = $sector->get_data_for({
233 key_md5 => $self->_apply_digest( $key ),
237 # exists() returns 1 or '' for true/false.
238 return $data ? 1 : '';
243 my ($obj, $key) = @_;
245 my $sector = $self->_load_sector( $obj->_base_offset )
248 if ( $sector->staleness != $obj->_staleness ) {
252 return $sector->delete_key({
253 key_md5 => $self->_apply_digest( $key ),
260 my ($obj, $key, $value) = @_;
262 my $r = Scalar::Util::reftype( $value ) || '';
265 last if $r eq 'HASH';
266 last if $r eq 'ARRAY';
268 DBM::Deep->_throw_error(
269 "Storage of references of type '$r' is not supported."
273 # This will be a Reference sector
274 my $sector = $self->_load_sector( $obj->_base_offset )
275 or DBM::Deep->_throw_error( "Cannot write to a deleted spot in DBM::Deep." );
277 if ( $sector->staleness != $obj->_staleness ) {
278 DBM::Deep->_throw_error( "Cannot write to a deleted spot in DBM::Deep." );
282 if ( !defined $value ) {
283 $class = 'DBM::Deep::Engine::Sector::Null';
285 elsif ( $r eq 'ARRAY' || $r eq 'HASH' ) {
287 if ( $r eq 'ARRAY' ) {
288 $tmpvar = tied @$value;
289 } elsif ( $r eq 'HASH' ) {
290 $tmpvar = tied %$value;
294 my $is_dbm_deep = eval { local $SIG{'__DIE__'}; $tmpvar->isa( 'DBM::Deep' ); };
296 unless ( $is_dbm_deep ) {
297 DBM::Deep->_throw_error( "Cannot store something that is tied." );
300 unless ( $tmpvar->_engine->storage == $self->storage ) {
301 DBM::Deep->_throw_error( "Cannot store values across DBM::Deep files. Please use export() instead." );
304 # First, verify if we're storing the same thing to this spot. If we are, then
305 # this should be a no-op. -EJS, 2008-05-19
306 my $loc = $sector->get_data_location_for({
307 key_md5 => $self->_apply_digest( $key ),
311 if ( defined($loc) && $loc == $tmpvar->_base_offset ) {
315 #XXX Can this use $loc?
316 my $value_sector = $self->_load_sector( $tmpvar->_base_offset );
317 $sector->write_data({
319 key_md5 => $self->_apply_digest( $key ),
320 value => $value_sector,
322 $value_sector->increment_refcount;
327 $class = 'DBM::Deep::Engine::Sector::Reference';
328 $type = substr( $r, 0, 1 );
331 if ( tied($value) ) {
332 DBM::Deep->_throw_error( "Cannot store something that is tied." );
334 $class = 'DBM::Deep::Engine::Sector::Scalar';
337 # Create this after loading the reference sector in case something bad happens.
338 # This way, we won't allocate value sector(s) needlessly.
339 my $value_sector = $class->new({
345 $sector->write_data({
347 key_md5 => $self->_apply_digest( $key ),
348 value => $value_sector,
351 # This code is to make sure we write all the values in the $value to the disk
352 # and to make sure all changes to $value after the assignment are reflected
353 # on disk. This may be counter-intuitive at first, but it is correct dwimmery.
354 # NOTE - simply tying $value won't perform a STORE on each value. Hence, the
355 # copy to a temp value.
356 if ( $r eq 'ARRAY' ) {
358 tie @$value, 'DBM::Deep', {
359 base_offset => $value_sector->offset,
360 staleness => $value_sector->staleness,
361 storage => $self->storage,
365 bless $value, 'DBM::Deep::Array' unless Scalar::Util::blessed( $value );
367 elsif ( $r eq 'HASH' ) {
369 tie %$value, 'DBM::Deep', {
370 base_offset => $value_sector->offset,
371 staleness => $value_sector->staleness,
372 storage => $self->storage,
377 bless $value, 'DBM::Deep::Hash' unless Scalar::Util::blessed( $value );
383 # XXX Add staleness here
386 my ($obj, $prev_key) = @_;
388 # XXX Need to add logic about resetting the iterator if any key in the reference has changed
389 unless ( $prev_key ) {
390 $obj->{iterator} = DBM::Deep::Iterator->new({
391 base_offset => $obj->_base_offset,
396 return $obj->{iterator}->get_next_key( $obj );
399 ################################################################################
405 # We're opening the file.
406 unless ( $obj->_base_offset ) {
407 my $bytes_read = $self->_read_file_header;
409 # Creating a new file
410 unless ( $bytes_read ) {
411 $self->_write_file_header;
413 # 1) Create Array/Hash entry
414 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
418 $obj->{base_offset} = $initial_reference->offset;
419 $obj->{staleness} = $initial_reference->staleness;
421 $self->storage->flush;
423 # Reading from an existing file
425 $obj->{base_offset} = $bytes_read;
426 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
428 offset => $obj->_base_offset,
430 unless ( $initial_reference ) {
431 DBM::Deep->_throw_error("Corrupted file, no master index record");
434 unless ($obj->_type eq $initial_reference->type) {
435 DBM::Deep->_throw_error("File type mismatch");
438 $obj->{staleness} = $initial_reference->staleness;
449 if ( $self->trans_id ) {
450 DBM::Deep->_throw_error( "Cannot begin_work within an active transaction" );
453 my @slots = $self->read_txn_slots;
455 for my $i ( 0 .. $#slots ) {
459 $self->set_trans_id( $i + 1 );
464 DBM::Deep->_throw_error( "Cannot allocate transaction ID" );
466 $self->write_txn_slots( @slots );
468 if ( !$self->trans_id ) {
469 DBM::Deep->_throw_error( "Cannot begin_work - no available transactions" );
479 if ( !$self->trans_id ) {
480 DBM::Deep->_throw_error( "Cannot rollback without an active transaction" );
483 # Each entry is the file location for a bucket that has a modification for
484 # this transaction. The entries need to be expunged.
485 foreach my $entry (@{ $self->get_entries } ) {
486 # Remove the entry here
487 my $read_loc = $entry
491 + ($self->trans_id - 1) * ( $self->byte_size + $STALE_SIZE );
493 my $data_loc = $self->storage->read_at( $read_loc, $self->byte_size );
494 $data_loc = unpack( $StP{$self->byte_size}, $data_loc );
495 $self->storage->print_at( $read_loc, pack( $StP{$self->byte_size}, 0 ) );
497 if ( $data_loc > 1 ) {
498 $self->_load_sector( $data_loc )->free;
502 $self->clear_entries;
504 my @slots = $self->read_txn_slots;
505 $slots[$self->trans_id-1] = 0;
506 $self->write_txn_slots( @slots );
507 $self->inc_txn_staleness_counter( $self->trans_id );
508 $self->set_trans_id( 0 );
517 if ( !$self->trans_id ) {
518 DBM::Deep->_throw_error( "Cannot commit without an active transaction" );
521 foreach my $entry (@{ $self->get_entries } ) {
522 # Overwrite the entry in head with the entry in trans_id
527 my $head_loc = $self->storage->read_at( $base, $self->byte_size );
528 $head_loc = unpack( $StP{$self->byte_size}, $head_loc );
530 my $spot = $base + $self->byte_size + ($self->trans_id - 1) * ( $self->byte_size + $STALE_SIZE );
531 my $trans_loc = $self->storage->read_at(
532 $spot, $self->byte_size,
535 $self->storage->print_at( $base, $trans_loc );
536 $self->storage->print_at(
538 pack( $StP{$self->byte_size} . ' ' . $StP{$STALE_SIZE}, (0) x 2 ),
541 if ( $head_loc > 1 ) {
542 $self->_load_sector( $head_loc )->free;
546 $self->clear_entries;
548 my @slots = $self->read_txn_slots;
549 $slots[$self->trans_id-1] = 0;
550 $self->write_txn_slots( @slots );
551 $self->inc_txn_staleness_counter( $self->trans_id );
552 $self->set_trans_id( 0 );
559 my $bl = $self->txn_bitfield_len;
560 my $num_bits = $bl * 8;
561 return split '', unpack( 'b'.$num_bits,
562 $self->storage->read_at(
563 $self->trans_loc, $bl,
568 sub write_txn_slots {
570 my $num_bits = $self->txn_bitfield_len * 8;
571 $self->storage->print_at( $self->trans_loc,
572 pack( 'b'.$num_bits, join('', @_) ),
576 sub get_running_txn_ids {
578 my @transactions = $self->read_txn_slots;
579 my @trans_ids = map { $_+1} grep { $transactions[$_] } 0 .. $#transactions;
582 sub get_txn_staleness_counter {
586 # Hardcode staleness of 0 for the HEAD
587 return 0 unless $trans_id;
589 return unpack( $StP{$STALE_SIZE},
590 $self->storage->read_at(
591 $self->trans_loc + $self->txn_bitfield_len + $STALE_SIZE * ($trans_id - 1),
597 sub inc_txn_staleness_counter {
601 # Hardcode staleness of 0 for the HEAD
602 return 0 unless $trans_id;
604 $self->storage->print_at(
605 $self->trans_loc + $self->txn_bitfield_len + $STALE_SIZE * ($trans_id - 1),
606 pack( $StP{$STALE_SIZE}, $self->get_txn_staleness_counter( $trans_id ) + 1 ),
612 return [ keys %{ $self->{entries}{$self->trans_id} ||= {} } ];
617 my ($trans_id, $loc) = @_;
619 $self->{entries}{$trans_id} ||= {};
620 $self->{entries}{$trans_id}{$loc} = undef;
623 # If the buckets are being relocated because of a reindexing, the entries
624 # mechanism needs to be made aware of it.
627 my ($old_loc, $new_loc) = @_;
630 while ( my ($trans_id, $locs) = each %{ $self->{entries} } ) {
631 if ( exists $locs->{$old_loc} ) {
632 delete $locs->{$old_loc};
633 $locs->{$new_loc} = undef;
641 delete $self->{entries}{$self->trans_id};
644 ################################################################################
647 my $header_fixed = length( SIG_FILE ) + 1 + 4 + 4;
648 my $this_file_version = 3;
650 sub _write_file_header {
653 my $nt = $self->num_txns;
654 my $bl = $self->txn_bitfield_len;
656 my $header_var = 1 + 1 + 1 + 1 + $bl + $STALE_SIZE * ($nt - 1) + 3 * $self->byte_size;
658 my $loc = $self->storage->request_space( $header_fixed + $header_var );
660 $self->storage->print_at( $loc,
663 pack('N', $this_file_version), # At this point, we're at 9 bytes
664 pack('N', $header_var), # header size
665 # --- Above is $header_fixed. Below is $header_var
666 pack('C', $self->byte_size),
668 # These shenanigans are to allow a 256 within a C
669 pack('C', $self->max_buckets - 1),
670 pack('C', $self->data_sector_size - 1),
673 pack('C' . $bl, 0 ), # Transaction activeness bitfield
674 pack($StP{$STALE_SIZE}.($nt-1), 0 x ($nt-1) ), # Transaction staleness counters
675 pack($StP{$self->byte_size}, 0), # Start of free chain (blist size)
676 pack($StP{$self->byte_size}, 0), # Start of free chain (data size)
677 pack($StP{$self->byte_size}, 0), # Start of free chain (index size)
680 #XXX Set these less fragilely
681 $self->set_trans_loc( $header_fixed + 4 );
682 $self->set_chains_loc( $header_fixed + 4 + $bl + $STALE_SIZE * ($nt-1) );
687 sub _read_file_header {
690 my $buffer = $self->storage->read_at( 0, $header_fixed );
691 return unless length($buffer);
693 my ($file_signature, $sig_header, $file_version, $size) = unpack(
697 unless ( $file_signature eq SIG_FILE ) {
698 $self->storage->close;
699 DBM::Deep->_throw_error( "Signature not found -- file is not a Deep DB" );
702 unless ( $sig_header eq SIG_HEADER ) {
703 $self->storage->close;
704 DBM::Deep->_throw_error( "Pre-1.00 file version found" );
707 unless ( $file_version == $this_file_version ) {
708 $self->storage->close;
709 DBM::Deep->_throw_error(
710 "Wrong file version found - " . $file_version .
711 " - expected " . $this_file_version
715 my $buffer2 = $self->storage->read_at( undef, $size );
716 my @values = unpack( 'C C C C', $buffer2 );
718 if ( @values != 4 || grep { !defined } @values ) {
719 $self->storage->close;
720 DBM::Deep->_throw_error("Corrupted file - bad header");
723 #XXX Add warnings if values weren't set right
724 @{$self}{qw(byte_size max_buckets data_sector_size num_txns)} = @values;
726 # These shenangians are to allow a 256 within a C
727 $self->{max_buckets} += 1;
728 $self->{data_sector_size} += 1;
730 my $bl = $self->txn_bitfield_len;
732 my $header_var = scalar(@values) + $bl + $STALE_SIZE * ($self->num_txns - 1) + 3 * $self->byte_size;
733 unless ( $size == $header_var ) {
734 $self->storage->close;
735 DBM::Deep->_throw_error( "Unexpected size found ($size <-> $header_var)." );
738 $self->set_trans_loc( $header_fixed + scalar(@values) );
739 $self->set_chains_loc( $header_fixed + scalar(@values) + $bl + $STALE_SIZE * ($self->num_txns - 1) );
741 return length($buffer) + length($buffer2);
749 # Add a catch for offset of 0 or 1
750 return if !$offset || $offset <= 1;
752 my $type = $self->storage->read_at( $offset, 1 );
753 return if $type eq chr(0);
755 if ( $type eq $self->SIG_ARRAY || $type eq $self->SIG_HASH ) {
756 return DBM::Deep::Engine::Sector::Reference->new({
762 # XXX Don't we need key_md5 here?
763 elsif ( $type eq $self->SIG_BLIST ) {
764 return DBM::Deep::Engine::Sector::BucketList->new({
770 elsif ( $type eq $self->SIG_INDEX ) {
771 return DBM::Deep::Engine::Sector::Index->new({
777 elsif ( $type eq $self->SIG_NULL ) {
778 return DBM::Deep::Engine::Sector::Null->new({
784 elsif ( $type eq $self->SIG_DATA ) {
785 return DBM::Deep::Engine::Sector::Scalar->new({
791 # This was deleted from under us, so just return and let the caller figure it out.
792 elsif ( $type eq $self->SIG_FREE ) {
796 DBM::Deep->_throw_error( "'$offset': Don't know what to do with type '$type'" );
801 return $self->{digest}->(@_);
804 sub _add_free_blist_sector { shift->_add_free_sector( 0, @_ ) }
805 sub _add_free_data_sector { shift->_add_free_sector( 1, @_ ) }
806 sub _add_free_index_sector { shift->_add_free_sector( 2, @_ ) }
808 sub _add_free_sector {
810 my ($multiple, $offset, $size) = @_;
812 my $chains_offset = $multiple * $self->byte_size;
814 my $storage = $self->storage;
816 # Increment staleness.
817 # XXX Can this increment+modulo be done by "&= 0x1" ?
818 my $staleness = unpack( $StP{$STALE_SIZE}, $storage->read_at( $offset + SIG_SIZE, $STALE_SIZE ) );
819 $staleness = ($staleness + 1 ) % ( 2 ** ( 8 * $STALE_SIZE ) );
820 $storage->print_at( $offset + SIG_SIZE, pack( $StP{$STALE_SIZE}, $staleness ) );
822 my $old_head = $storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
824 $storage->print_at( $self->chains_loc + $chains_offset,
825 pack( $StP{$self->byte_size}, $offset ),
828 # Record the old head in the new sector after the signature and staleness counter
829 $storage->print_at( $offset + SIG_SIZE + $STALE_SIZE, $old_head );
832 sub _request_blist_sector { shift->_request_sector( 0, @_ ) }
833 sub _request_data_sector { shift->_request_sector( 1, @_ ) }
834 sub _request_index_sector { shift->_request_sector( 2, @_ ) }
836 sub _request_sector {
838 my ($multiple, $size) = @_;
840 my $chains_offset = $multiple * $self->byte_size;
842 my $old_head = $self->storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
843 my $loc = unpack( $StP{$self->byte_size}, $old_head );
845 # We don't have any free sectors of the right size, so allocate a new one.
847 my $offset = $self->storage->request_space( $size );
849 # Zero out the new sector. This also guarantees correct increases
851 $self->storage->print_at( $offset, chr(0) x $size );
856 # Read the new head after the signature and the staleness counter
857 my $new_head = $self->storage->read_at( $loc + SIG_SIZE + $STALE_SIZE, $self->byte_size );
858 $self->storage->print_at( $self->chains_loc + $chains_offset, $new_head );
859 $self->storage->print_at(
860 $loc + SIG_SIZE + $STALE_SIZE,
861 pack( $StP{$self->byte_size}, 0 ),
867 ################################################################################
869 sub storage { $_[0]{storage} }
870 sub byte_size { $_[0]{byte_size} }
871 sub hash_size { $_[0]{hash_size} }
872 sub hash_chars { $_[0]{hash_chars} }
873 sub num_txns { $_[0]{num_txns} }
874 sub max_buckets { $_[0]{max_buckets} }
875 sub blank_md5 { chr(0) x $_[0]->hash_size }
876 sub data_sector_size { $_[0]{data_sector_size} }
878 # This is a calculated value
879 sub txn_bitfield_len {
881 unless ( exists $self->{txn_bitfield_len} ) {
882 my $temp = ($self->num_txns) / 8;
883 if ( $temp > int( $temp ) ) {
884 $temp = int( $temp ) + 1;
886 $self->{txn_bitfield_len} = $temp;
888 return $self->{txn_bitfield_len};
891 sub trans_id { $_[0]{trans_id} }
892 sub set_trans_id { $_[0]{trans_id} = $_[1] }
894 sub trans_loc { $_[0]{trans_loc} }
895 sub set_trans_loc { $_[0]{trans_loc} = $_[1] }
897 sub chains_loc { $_[0]{chains_loc} }
898 sub set_chains_loc { $_[0]{chains_loc} = $_[1] }
900 sub cache { $_[0]{cache} ||= {} }
901 sub clear_cache { %{$_[0]->cache} = () }
907 my $spot = $self->_read_file_header();
916 'D' => $self->data_sector_size,
917 'B' => DBM::Deep::Engine::Sector::BucketList->new({engine=>$self,offset=>1})->size,
918 'I' => DBM::Deep::Engine::Sector::Index->new({engine=>$self,offset=>1})->size,
924 $return .= "NumTxns: " . $self->num_txns . $/;
926 # Read the free sector chains
928 foreach my $multiple ( 0 .. 2 ) {
929 $return .= "Chains($types{$multiple}):";
930 my $old_loc = $self->chains_loc + $multiple * $self->byte_size;
933 $StP{$self->byte_size},
934 $self->storage->read_at( $old_loc, $self->byte_size ),
937 # We're now out of free sectors of this kind.
942 $sectors{ $types{$multiple} }{ $loc } = undef;
943 $old_loc = $loc + SIG_SIZE + $STALE_SIZE;
950 while ( $spot < $self->storage->{end} ) {
951 # Read each sector in order.
952 my $sector = $self->_load_sector( $spot );
954 # Find it in the free-sectors that were found already
955 foreach my $type ( keys %sectors ) {
956 if ( exists $sectors{$type}{$spot} ) {
957 my $size = $sizes{$type};
958 $return .= sprintf "%08d: %s %04d\n", $spot, 'F' . $type, $size;
964 die "********\n$return\nDidn't find free sector for $spot in chains\n********\n";
967 $return .= sprintf "%08d: %s %04d", $spot, $sector->type, $sector->size;
968 if ( $sector->type eq 'D' ) {
969 $return .= ' ' . $sector->data;
971 elsif ( $sector->type eq 'A' || $sector->type eq 'H' ) {
972 $return .= ' REF: ' . $sector->get_refcount;
974 elsif ( $sector->type eq 'B' ) {
975 foreach my $bucket ( $sector->chopped_up ) {
977 $return .= sprintf "%08d", unpack($StP{$self->byte_size},
978 substr( $bucket->[-1], $self->hash_size, $self->byte_size),
980 my $l = unpack( $StP{$self->byte_size},
981 substr( $bucket->[-1],
982 $self->hash_size + $self->byte_size,
986 $return .= sprintf " %08d", $l;
987 foreach my $txn ( 0 .. $self->num_txns - 2 ) {
988 my $l = unpack( $StP{$self->byte_size},
989 substr( $bucket->[-1],
990 $self->hash_size + 2 * $self->byte_size + $txn * ($self->byte_size + $STALE_SIZE),
994 $return .= sprintf " %08d", $l;
1000 $spot += $sector->size;
1007 ################################################################################
1009 package DBM::Deep::Iterator;
1017 engine => $args->{engine},
1018 base_offset => $args->{base_offset},
1021 Scalar::Util::weaken( $self->{engine} );
1026 sub reset { $_[0]{breadcrumbs} = [] }
1028 sub get_sector_iterator {
1032 my $sector = $self->{engine}->_load_sector( $loc )
1035 if ( $sector->isa( 'DBM::Deep::Engine::Sector::Index' ) ) {
1036 return DBM::Deep::Iterator::Index->new({
1041 elsif ( $sector->isa( 'DBM::Deep::Engine::Sector::BucketList' ) ) {
1042 return DBM::Deep::Iterator::BucketList->new({
1048 DBM::Deep->_throw_error( "get_sector_iterator(): Why did $loc make a $sector?" );
1055 my $crumbs = $self->{breadcrumbs};
1056 my $e = $self->{engine};
1058 unless ( @$crumbs ) {
1059 # This will be a Reference sector
1060 my $sector = $e->_load_sector( $self->{base_offset} )
1061 # If no sector is found, thist must have been deleted from under us.
1064 if ( $sector->staleness != $obj->_staleness ) {
1068 my $loc = $sector->get_blist_loc
1071 push @$crumbs, $self->get_sector_iterator( $loc );
1076 unless ( @$crumbs ) {
1081 my $iterator = $crumbs->[-1];
1083 # This level is done.
1084 if ( $iterator->at_end ) {
1089 if ( $iterator->isa( 'DBM::Deep::Iterator::Index' ) ) {
1090 # If we don't have any more, it will be caught at the
1092 if ( my $next = $iterator->get_next_iterator ) {
1093 push @$crumbs, $next;
1098 unless ( $iterator->isa( 'DBM::Deep::Iterator::BucketList' ) ) {
1099 DBM::Deep->_throw_error(
1100 "Should have a bucketlist iterator here - instead have $iterator"
1104 # At this point, we have a BucketList iterator
1105 my $key = $iterator->get_next_key;
1106 if ( defined $key ) {
1109 #XXX else { $iterator->set_to_end() } ?
1111 # We hit the end of the bucketlist iterator, so redo
1115 DBM::Deep->_throw_error( "get_next_key(): How did we get here?" );
1118 package DBM::Deep::Iterator::Index;
1121 my $self = bless $_[1] => $_[0];
1122 $self->{curr_index} = 0;
1128 return $self->{curr_index} >= $self->{iterator}{engine}->hash_chars;
1131 sub get_next_iterator {
1136 return if $self->at_end;
1137 $loc = $self->{sector}->get_entry( $self->{curr_index}++ );
1140 return $self->{iterator}->get_sector_iterator( $loc );
1143 package DBM::Deep::Iterator::BucketList;
1146 my $self = bless $_[1] => $_[0];
1147 $self->{curr_index} = 0;
1153 return $self->{curr_index} >= $self->{iterator}{engine}->max_buckets;
1159 return if $self->at_end;
1161 my $idx = $self->{curr_index}++;
1163 my $data_loc = $self->{sector}->get_data_location_for({
1168 #XXX Do we want to add corruption checks here?
1169 return $self->{sector}->get_key_for( $idx )->data;
1172 package DBM::Deep::Engine::Sector;
1175 my $self = bless $_[1], $_[0];
1176 Scalar::Util::weaken( $self->{engine} );
1182 #sub clone { DBM::Deep->_throw_error( "Must be implemented in the child class" ); }
1184 sub engine { $_[0]{engine} }
1185 sub offset { $_[0]{offset} }
1186 sub type { $_[0]{type} }
1190 return $self->engine->SIG_SIZE + $STALE_SIZE;
1196 my $e = $self->engine;
1198 $e->storage->print_at( $self->offset, $e->SIG_FREE );
1199 # Skip staleness counter
1200 $e->storage->print_at( $self->offset + $self->base_size,
1201 chr(0) x ($self->size - $self->base_size),
1204 my $free_meth = $self->free_meth;
1205 $e->$free_meth( $self->offset, $self->size );
1210 package DBM::Deep::Engine::Sector::Data;
1212 our @ISA = qw( DBM::Deep::Engine::Sector );
1215 sub size { $_[0]{engine}->data_sector_size }
1216 sub free_meth { return '_add_free_data_sector' }
1220 return ref($self)->new({
1221 engine => $self->engine,
1222 type => $self->type,
1223 data => $self->data,
1227 package DBM::Deep::Engine::Sector::Scalar;
1229 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1234 my $chain_loc = $self->chain_loc;
1236 $self->SUPER::free();
1239 $self->engine->_load_sector( $chain_loc )->free;
1245 sub type { $_[0]{engine}->SIG_DATA }
1249 my $engine = $self->engine;
1251 unless ( $self->offset ) {
1252 my $data_section = $self->size - $self->base_size - $engine->byte_size - 1;
1254 $self->{offset} = $engine->_request_data_sector( $self->size );
1256 my $data = delete $self->{data};
1257 my $dlen = length $data;
1259 my $curr_offset = $self->offset;
1260 while ( $continue ) {
1262 my $next_offset = 0;
1264 my ($leftover, $this_len, $chunk);
1265 if ( $dlen > $data_section ) {
1267 $this_len = $data_section;
1268 $chunk = substr( $data, 0, $this_len );
1270 $dlen -= $data_section;
1271 $next_offset = $engine->_request_data_sector( $self->size );
1272 $data = substr( $data, $this_len );
1275 $leftover = $data_section - $dlen;
1282 $engine->storage->print_at( $curr_offset, $self->type ); # Sector type
1284 $engine->storage->print_at( $curr_offset + $self->base_size,
1285 pack( $StP{$engine->byte_size}, $next_offset ), # Chain loc
1286 pack( $StP{1}, $this_len ), # Data length
1287 $chunk, # Data to be stored in this sector
1288 chr(0) x $leftover, # Zero-fill the rest
1291 $curr_offset = $next_offset;
1301 my $buffer = $self->engine->storage->read_at(
1302 $self->offset + $self->base_size + $self->engine->byte_size, 1
1305 return unpack( $StP{1}, $buffer );
1311 $StP{$self->engine->byte_size},
1312 $self->engine->storage->read_at(
1313 $self->offset + $self->base_size,
1314 $self->engine->byte_size,
1326 my $chain_loc = $self->chain_loc;
1328 $data .= $self->engine->storage->read_at(
1329 $self->offset + $self->base_size + $self->engine->byte_size + 1, $self->data_length,
1332 last unless $chain_loc;
1334 $self = $self->engine->_load_sector( $chain_loc );
1340 package DBM::Deep::Engine::Sector::Null;
1342 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1344 sub type { $_[0]{engine}->SIG_NULL }
1345 sub data_length { 0 }
1351 my $engine = $self->engine;
1353 unless ( $self->offset ) {
1354 my $leftover = $self->size - $self->base_size - 1 * $engine->byte_size - 1;
1356 $self->{offset} = $engine->_request_data_sector( $self->size );
1357 $engine->storage->print_at( $self->offset, $self->type ); # Sector type
1358 # Skip staleness counter
1359 $engine->storage->print_at( $self->offset + $self->base_size,
1360 pack( $StP{$engine->byte_size}, 0 ), # Chain loc
1361 pack( $StP{1}, $self->data_length ), # Data length
1362 chr(0) x $leftover, # Zero-fill the rest
1369 package DBM::Deep::Engine::Sector::Reference;
1371 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1376 my $e = $self->engine;
1378 unless ( $self->offset ) {
1379 my $classname = Scalar::Util::blessed( delete $self->{data} );
1380 my $leftover = $self->size - $self->base_size - 3 * $e->byte_size;
1382 my $class_offset = 0;
1383 if ( defined $classname ) {
1384 my $class_sector = DBM::Deep::Engine::Sector::Scalar->new({
1388 $class_offset = $class_sector->offset;
1391 $self->{offset} = $e->_request_data_sector( $self->size );
1392 $e->storage->print_at( $self->offset, $self->type ); # Sector type
1393 # Skip staleness counter
1394 $e->storage->print_at( $self->offset + $self->base_size,
1395 pack( $StP{$e->byte_size}, 0 ), # Index/BList loc
1396 pack( $StP{$e->byte_size}, $class_offset ), # Classname loc
1397 pack( $StP{$e->byte_size}, 1 ), # Initial refcount
1398 chr(0) x $leftover, # Zero-fill the rest
1402 $self->{type} = $e->storage->read_at( $self->offset, 1 );
1405 $self->{staleness} = unpack(
1407 $e->storage->read_at( $self->offset + $e->SIG_SIZE, $STALE_SIZE ),
1413 sub staleness { $_[0]{staleness} }
1415 sub get_data_location_for {
1419 # Assume that the head is not allowed unless otherwise specified.
1420 $args->{allow_head} = 0 unless exists $args->{allow_head};
1422 # Assume we don't create a new blist location unless otherwise specified.
1423 $args->{create} = 0 unless exists $args->{create};
1425 my $blist = $self->get_bucket_list({
1426 key_md5 => $args->{key_md5},
1427 key => $args->{key},
1428 create => $args->{create},
1430 return unless $blist && $blist->{found};
1432 # At this point, $blist knows where the md5 is. What it -doesn't- know yet
1433 # is whether or not this transaction has this key. That's part of the next
1435 my $location = $blist->get_data_location_for({
1436 allow_head => $args->{allow_head},
1446 my $location = $self->get_data_location_for( $args )
1449 return $self->engine->_load_sector( $location );
1456 my $blist = $self->get_bucket_list({
1457 key_md5 => $args->{key_md5},
1458 key => $args->{key},
1460 }) or DBM::Deep->_throw_error( "How did write_data fail (no blist)?!" );
1462 # Handle any transactional bookkeeping.
1463 if ( $self->engine->trans_id ) {
1464 if ( ! $blist->has_md5 ) {
1465 $blist->mark_deleted({
1471 my @trans_ids = $self->engine->get_running_txn_ids;
1472 if ( $blist->has_md5 ) {
1474 my $old_value = $blist->get_data_for;
1475 foreach my $other_trans_id ( @trans_ids ) {
1476 next if $blist->get_data_location_for({
1477 trans_id => $other_trans_id,
1481 trans_id => $other_trans_id,
1482 key => $args->{key},
1483 key_md5 => $args->{key_md5},
1484 value => $old_value->clone,
1491 foreach my $other_trans_id ( @trans_ids ) {
1492 #XXX This doesn't seem to possible to ever happen . . .
1493 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1494 $blist->mark_deleted({
1495 trans_id => $other_trans_id,
1502 #XXX Is this safe to do transactionally?
1503 # Free the place we're about to write to.
1504 if ( $blist->get_data_location_for({ allow_head => 0 }) ) {
1505 $blist->get_data_for({ allow_head => 0 })->free;
1509 key => $args->{key},
1510 key_md5 => $args->{key_md5},
1511 value => $args->{value},
1519 # XXX What should happen if this fails?
1520 my $blist = $self->get_bucket_list({
1521 key_md5 => $args->{key_md5},
1522 }) or DBM::Deep->_throw_error( "How did delete_key fail (no blist)?!" );
1524 # Save the location so that we can free the data
1525 my $location = $blist->get_data_location_for({
1528 my $old_value = $location && $self->engine->_load_sector( $location );
1530 my @trans_ids = $self->engine->get_running_txn_ids;
1532 # If we're the HEAD and there are running txns, then we need to clone this value to the other
1533 # transactions to preserve Isolation.
1534 if ( $self->engine->trans_id == 0 ) {
1536 foreach my $other_trans_id ( @trans_ids ) {
1537 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1539 trans_id => $other_trans_id,
1540 key => $args->{key},
1541 key_md5 => $args->{key_md5},
1542 value => $old_value->clone,
1550 $blist->mark_deleted( $args );
1553 $data = $old_value->data({ export => 1 });
1558 $data = $blist->delete_md5( $args );
1567 my $e = $self->engine;
1568 my $blist_loc = $e->storage->read_at( $self->offset + $self->base_size, $e->byte_size );
1569 return unpack( $StP{$e->byte_size}, $blist_loc );
1572 sub get_bucket_list {
1577 # XXX Add in check here for recycling?
1579 my $engine = $self->engine;
1581 my $blist_loc = $self->get_blist_loc;
1583 # There's no index or blist yet
1584 unless ( $blist_loc ) {
1585 return unless $args->{create};
1587 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1589 key_md5 => $args->{key_md5},
1592 $engine->storage->print_at( $self->offset + $self->base_size,
1593 pack( $StP{$engine->byte_size}, $blist->offset ),
1599 my $sector = $engine->_load_sector( $blist_loc )
1600 or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
1602 my $last_sector = undef;
1603 while ( $sector->isa( 'DBM::Deep::Engine::Sector::Index' ) ) {
1604 $blist_loc = $sector->get_entry( ord( substr( $args->{key_md5}, $i++, 1 ) ) );
1605 $last_sector = $sector;
1607 $sector = $engine->_load_sector( $blist_loc )
1608 or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
1616 # This means we went through the Index sector(s) and found an empty slot
1617 unless ( $sector ) {
1618 return unless $args->{create};
1620 DBM::Deep->_throw_error( "No last_sector when attempting to build a new entry" )
1621 unless $last_sector;
1623 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1625 key_md5 => $args->{key_md5},
1628 $last_sector->set_entry( ord( substr( $args->{key_md5}, $i - 1, 1 ) ) => $blist->offset );
1633 $sector->find_md5( $args->{key_md5} );
1635 # See whether or not we need to reindex the bucketlist
1636 # Yes, the double-braces are there for a reason. if() doesn't create a redo-able block,
1637 # so we have to create a bare block within the if() for redo-purposes. Patch and idea
1638 # submitted by sprout@cpan.org. -RobK, 2008-01-09
1639 if ( !$sector->has_md5 && $args->{create} && $sector->{idx} == -1 ) {{
1642 my $new_index = DBM::Deep::Engine::Sector::Index->new({
1647 #XXX q.v. the comments for this function.
1648 foreach my $entry ( $sector->chopped_up ) {
1649 my ($spot, $md5) = @{$entry};
1650 my $idx = ord( substr( $md5, $i, 1 ) );
1652 # XXX This is inefficient
1653 my $blist = $blist_cache{$idx}
1654 ||= DBM::Deep::Engine::Sector::BucketList->new({
1658 $new_index->set_entry( $idx => $blist->offset );
1660 my $new_spot = $blist->write_at_next_open( $md5 );
1661 $engine->reindex_entry( $spot => $new_spot );
1664 # Handle the new item separately.
1666 my $idx = ord( substr( $args->{key_md5}, $i, 1 ) );
1668 # If all the previous blist's items have been thrown into one
1669 # blist and the new item belongs in there too, we need
1671 if ( keys %blist_cache == 1 and each %blist_cache == $idx ) {
1674 my $blist = $blist_cache{$idx}
1675 ||= DBM::Deep::Engine::Sector::BucketList->new({
1679 $new_index->set_entry( $idx => $blist->offset );
1682 $blist->find_md5( $args->{key_md5} );
1684 key => $args->{key},
1685 key_md5 => $args->{key_md5},
1686 value => DBM::Deep::Engine::Sector::Null->new({
1692 # my $blist = $blist_cache{$idx}
1693 # ||= DBM::Deep::Engine::Sector::BucketList->new({
1694 # engine => $engine,
1697 # $new_index->set_entry( $idx => $blist->offset );
1699 # #XXX THIS IS HACKY!
1700 # $blist->find_md5( $args->{key_md5} );
1701 # $blist->write_md5({
1702 # key => $args->{key},
1703 # key_md5 => $args->{key_md5},
1704 # value => DBM::Deep::Engine::Sector::Null->new({
1705 # engine => $engine,
1711 if ( $last_sector ) {
1712 $last_sector->set_entry(
1713 ord( substr( $args->{key_md5}, $i - 1, 1 ) ),
1717 $engine->storage->print_at( $self->offset + $self->base_size,
1718 pack( $StP{$engine->byte_size}, $new_index->offset ),
1726 (undef, $sector) = %blist_cache;
1727 $last_sector = $new_index;
1731 $sector = $blist_cache{ ord( substr( $args->{key_md5}, $i, 1 ) ) };
1732 $sector->find_md5( $args->{key_md5} );
1738 sub get_class_offset {
1741 my $e = $self->engine;
1743 $StP{$e->byte_size},
1744 $e->storage->read_at(
1745 $self->offset + $self->base_size + 1 * $e->byte_size, $e->byte_size,
1753 my $class_offset = $self->get_class_offset;
1755 return unless $class_offset;
1757 return $self->engine->_load_sector( $class_offset )->data;
1766 unless ( $obj = $self->engine->cache->{ $self->offset } ) {
1767 $obj = DBM::Deep->new({
1768 type => $self->type,
1769 base_offset => $self->offset,
1770 staleness => $self->staleness,
1771 storage => $self->engine->storage,
1772 engine => $self->engine,
1775 if ( $self->engine->storage->{autobless} ) {
1776 my $classname = $self->get_classname;
1777 if ( defined $classname ) {
1778 bless $obj, $classname;
1782 $self->engine->cache->{$self->offset} = $obj;
1785 # We're not exporting, so just return.
1786 unless ( $args->{export} ) {
1790 # We shouldn't export if this is still referred to.
1791 if ( $self->get_refcount > 1 ) {
1795 return $obj->export;
1801 # We're not ready to be removed yet.
1802 if ( $self->decrement_refcount > 0 ) {
1806 # Rebless the object into DBM::Deep::Null.
1807 eval { %{ $self->engine->cache->{ $self->offset } } = (); };
1808 eval { @{ $self->engine->cache->{ $self->offset } } = (); };
1809 bless $self->engine->cache->{ $self->offset }, 'DBM::Deep::Null';
1810 delete $self->engine->cache->{ $self->offset };
1812 my $blist_loc = $self->get_blist_loc;
1813 $self->engine->_load_sector( $blist_loc )->free if $blist_loc;
1815 my $class_loc = $self->get_class_offset;
1816 $self->engine->_load_sector( $class_loc )->free if $class_loc;
1818 $self->SUPER::free();
1821 sub increment_refcount {
1824 my $refcount = $self->get_refcount;
1828 $self->write_refcount( $refcount );
1833 sub decrement_refcount {
1836 my $refcount = $self->get_refcount;
1840 $self->write_refcount( $refcount );
1848 my $e = $self->engine;
1850 $StP{$e->byte_size},
1851 $e->storage->read_at(
1852 $self->offset + $self->base_size + 2 * $e->byte_size, $e->byte_size,
1857 sub write_refcount {
1861 my $e = $self->engine;
1862 $e->storage->print_at(
1863 $self->offset + $self->base_size + 2 * $e->byte_size,
1864 pack( $StP{$e->byte_size}, $num ),
1868 package DBM::Deep::Engine::Sector::BucketList;
1870 our @ISA = qw( DBM::Deep::Engine::Sector );
1875 my $engine = $self->engine;
1877 unless ( $self->offset ) {
1878 my $leftover = $self->size - $self->base_size;
1880 $self->{offset} = $engine->_request_blist_sector( $self->size );
1881 $engine->storage->print_at( $self->offset, $engine->SIG_BLIST ); # Sector type
1882 # Skip staleness counter
1883 $engine->storage->print_at( $self->offset + $self->base_size,
1884 chr(0) x $leftover, # Zero-fill the data
1888 if ( $self->{key_md5} ) {
1897 $self->engine->storage->print_at( $self->offset + $self->base_size,
1898 chr(0) x ($self->size - $self->base_size), # Zero-fill the data
1904 unless ( $self->{size} ) {
1905 my $e = $self->engine;
1906 # Base + numbuckets * bucketsize
1907 $self->{size} = $self->base_size + $e->max_buckets * $self->bucket_size;
1909 return $self->{size};
1912 sub free_meth { return '_add_free_blist_sector' }
1917 my $e = $self->engine;
1918 foreach my $bucket ( $self->chopped_up ) {
1919 my $rest = $bucket->[-1];
1921 # Delete the keysector
1922 my $l = unpack( $StP{$e->byte_size}, substr( $rest, $e->hash_size, $e->byte_size ) );
1923 my $s = $e->_load_sector( $l ); $s->free if $s;
1925 # Delete the HEAD sector
1926 $l = unpack( $StP{$e->byte_size},
1928 $e->hash_size + $e->byte_size,
1932 $s = $e->_load_sector( $l ); $s->free if $s;
1934 foreach my $txn ( 0 .. $e->num_txns - 2 ) {
1935 my $l = unpack( $StP{$e->byte_size},
1937 $e->hash_size + 2 * $e->byte_size + $txn * ($e->byte_size + $STALE_SIZE),
1941 my $s = $e->_load_sector( $l ); $s->free if $s;
1945 $self->SUPER::free();
1950 unless ( $self->{bucket_size} ) {
1951 my $e = $self->engine;
1952 # Key + head (location) + transactions (location + staleness-counter)
1953 my $location_size = $e->byte_size + $e->byte_size + ($e->num_txns - 1) * ($e->byte_size + $STALE_SIZE);
1954 $self->{bucket_size} = $e->hash_size + $location_size;
1956 return $self->{bucket_size};
1959 # XXX This is such a poor hack. I need to rethink this code.
1963 my $e = $self->engine;
1966 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
1967 my $spot = $self->offset + $self->base_size + $idx * $self->bucket_size;
1968 my $md5 = $e->storage->read_at( $spot, $e->hash_size );
1970 #XXX If we're chopping, why would we ever have the blank_md5?
1971 last if $md5 eq $e->blank_md5;
1973 my $rest = $e->storage->read_at( undef, $self->bucket_size - $e->hash_size );
1974 push @buckets, [ $spot, $md5 . $rest ];
1980 sub write_at_next_open {
1984 #XXX This is such a hack!
1985 $self->{_next_open} = 0 unless exists $self->{_next_open};
1987 my $spot = $self->offset + $self->base_size + $self->{_next_open}++ * $self->bucket_size;
1988 $self->engine->storage->print_at( $spot, $entry );
1995 unless ( exists $self->{found} ) {
1998 return $self->{found};
2004 $self->{found} = undef;
2008 $self->{key_md5} = shift;
2011 # If we don't have an MD5, then what are we supposed to do?
2012 unless ( exists $self->{key_md5} ) {
2013 DBM::Deep->_throw_error( "Cannot find_md5 without a key_md5 set" );
2016 my $e = $self->engine;
2017 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
2018 my $potential = $e->storage->read_at(
2019 $self->offset + $self->base_size + $idx * $self->bucket_size, $e->hash_size,
2022 if ( $potential eq $e->blank_md5 ) {
2023 $self->{idx} = $idx;
2027 if ( $potential eq $self->{key_md5} ) {
2029 $self->{idx} = $idx;
2041 DBM::Deep->_throw_error( "write_md5: no key" ) unless exists $args->{key};
2042 DBM::Deep->_throw_error( "write_md5: no key_md5" ) unless exists $args->{key_md5};
2043 DBM::Deep->_throw_error( "write_md5: no value" ) unless exists $args->{value};
2045 my $engine = $self->engine;
2047 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
2049 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
2050 $engine->add_entry( $args->{trans_id}, $spot );
2052 unless ($self->{found}) {
2053 my $key_sector = DBM::Deep::Engine::Sector::Scalar->new({
2055 data => $args->{key},
2058 $engine->storage->print_at( $spot,
2060 pack( $StP{$engine->byte_size}, $key_sector->offset ),
2065 + $engine->hash_size
2066 + $engine->byte_size;
2068 if ( $args->{trans_id} ) {
2069 $loc += $engine->byte_size + ($args->{trans_id} - 1) * ( $engine->byte_size + $STALE_SIZE );
2071 $engine->storage->print_at( $loc,
2072 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
2073 pack( $StP{$STALE_SIZE}, $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
2077 $engine->storage->print_at( $loc,
2078 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
2088 my $engine = $self->engine;
2090 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
2092 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
2093 $engine->add_entry( $args->{trans_id}, $spot );
2096 + $engine->hash_size
2097 + $engine->byte_size;
2099 if ( $args->{trans_id} ) {
2100 $loc += $engine->byte_size + ($args->{trans_id} - 1) * ( $engine->byte_size + $STALE_SIZE );
2102 $engine->storage->print_at( $loc,
2103 pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
2104 pack( $StP{$STALE_SIZE}, $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
2108 $engine->storage->print_at( $loc,
2109 pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
2119 my $engine = $self->engine;
2120 return undef unless $self->{found};
2122 # Save the location so that we can free the data
2123 my $location = $self->get_data_location_for({
2126 my $key_sector = $self->get_key_for;
2128 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
2129 $engine->storage->print_at( $spot,
2130 $engine->storage->read_at(
2131 $spot + $self->bucket_size,
2132 $self->bucket_size * ( $engine->max_buckets - $self->{idx} - 1 ),
2134 chr(0) x $self->bucket_size,
2139 my $data_sector = $self->engine->_load_sector( $location );
2140 my $data = $data_sector->data({ export => 1 });
2146 sub get_data_location_for {
2151 $args->{allow_head} = 0 unless exists $args->{allow_head};
2152 $args->{trans_id} = $self->engine->trans_id unless exists $args->{trans_id};
2153 $args->{idx} = $self->{idx} unless exists $args->{idx};
2155 my $e = $self->engine;
2157 my $spot = $self->offset + $self->base_size
2158 + $args->{idx} * $self->bucket_size
2162 if ( $args->{trans_id} ) {
2163 $spot += $e->byte_size + ($args->{trans_id} - 1) * ( $e->byte_size + $STALE_SIZE );
2166 my $buffer = $e->storage->read_at(
2168 $e->byte_size + $STALE_SIZE,
2170 my ($loc, $staleness) = unpack( $StP{$e->byte_size} . ' ' . $StP{$STALE_SIZE}, $buffer );
2172 # XXX Merge the two if-clauses below
2173 if ( $args->{trans_id} ) {
2174 # We have found an entry that is old, so get rid of it
2175 if ( $staleness != (my $s = $e->get_txn_staleness_counter( $args->{trans_id} ) ) ) {
2176 $e->storage->print_at(
2178 pack( $StP{$e->byte_size} . ' ' . $StP{$STALE_SIZE}, (0) x 2 ),
2184 # If we're in a transaction and we never wrote to this location, try the
2186 if ( $args->{trans_id} && !$loc && $args->{allow_head} ) {
2187 return $self->get_data_location_for({
2190 idx => $args->{idx},
2194 return $loc <= 1 ? 0 : $loc;
2202 return unless $self->{found};
2203 my $location = $self->get_data_location_for({
2204 allow_head => $args->{allow_head},
2206 return $self->engine->_load_sector( $location );
2212 $idx = $self->{idx} unless defined $idx;
2214 if ( $idx >= $self->engine->max_buckets ) {
2215 DBM::Deep->_throw_error( "get_key_for(): Attempting to retrieve $idx" );
2218 my $location = $self->engine->storage->read_at(
2219 $self->offset + $self->base_size + $idx * $self->bucket_size + $self->engine->hash_size,
2220 $self->engine->byte_size,
2222 $location = unpack( $StP{$self->engine->byte_size}, $location );
2223 DBM::Deep->_throw_error( "get_key_for: No location?" ) unless $location;
2225 return $self->engine->_load_sector( $location );
2228 package DBM::Deep::Engine::Sector::Index;
2230 our @ISA = qw( DBM::Deep::Engine::Sector );
2235 my $engine = $self->engine;
2237 unless ( $self->offset ) {
2238 my $leftover = $self->size - $self->base_size;
2240 $self->{offset} = $engine->_request_index_sector( $self->size );
2241 $engine->storage->print_at( $self->offset, $engine->SIG_INDEX ); # Sector type
2242 # Skip staleness counter
2243 $engine->storage->print_at( $self->offset + $self->base_size,
2244 chr(0) x $leftover, # Zero-fill the rest
2254 unless ( $self->{size} ) {
2255 my $e = $self->engine;
2256 $self->{size} = $self->base_size + $e->byte_size * $e->hash_chars;
2258 return $self->{size};
2261 sub free_meth { return '_add_free_index_sector' }
2265 my $e = $self->engine;
2267 for my $i ( 0 .. $e->hash_chars - 1 ) {
2268 my $l = $self->get_entry( $i ) or next;
2269 $e->_load_sector( $l )->free;
2272 $self->SUPER::free();
2278 return $self->offset + $self->base_size + $idx * $self->engine->byte_size;
2285 my $e = $self->engine;
2287 DBM::Deep->_throw_error( "get_entry: Out of range ($idx)" )
2288 if $idx < 0 || $idx >= $e->hash_chars;
2291 $StP{$e->byte_size},
2292 $e->storage->read_at( $self->_loc_for( $idx ), $e->byte_size ),
2298 my ($idx, $loc) = @_;
2300 my $e = $self->engine;
2302 DBM::Deep->_throw_error( "set_entry: Out of range ($idx)" )
2303 if $idx < 0 || $idx >= $e->hash_chars;
2305 $self->engine->storage->print_at(
2306 $self->_loc_for( $idx ),
2307 pack( $StP{$e->byte_size}, $loc ),
2311 # This was copied from MARCEL's Class::Null. However, I couldn't use it because
2312 # I need an undef value, not an implementation of the Null Class pattern.
2313 package DBM::Deep::Null;
2316 'bool' => sub { undef },
2317 '""' => sub { undef },
2318 '0+' => sub { undef },
2320 nomethod => 'AUTOLOAD';
2322 sub AUTOLOAD { return; }