1 package DBM::Deep::Engine;
8 our $VERSION = q(1.0001);
13 # * Every method in here assumes that the storage has been appropriately
14 # safeguarded. This can be anything from flock() to some sort of manual
15 # mutex. But, it's the caller's responsability to make sure that this has
18 # Setup file and tag signatures. These should never change.
19 sub SIG_FILE () { 'DPDB' }
20 sub SIG_HEADER () { 'h' }
21 sub SIG_HASH () { 'H' }
22 sub SIG_ARRAY () { 'A' }
23 sub SIG_NULL () { 'N' }
24 sub SIG_DATA () { 'D' }
25 sub SIG_INDEX () { 'I' }
26 sub SIG_BLIST () { 'B' }
27 sub SIG_FREE () { 'F' }
32 # Please refer to the pack() documentation for further information
34 1 => 'C', # Unsigned char value (no order needed as it's just one byte)
35 2 => 'n', # Unsigned short in "network" (big-endian) order
36 4 => 'N', # Unsigned long in "network" (big-endian) order
37 8 => 'Q', # Usigned quad (no order specified, presumably machine-dependent)
40 ################################################################################
50 hash_size => 16, # In bytes
51 hash_chars => 256, # Number of chars the algorithm uses per byte
53 num_txns => 1, # The HEAD
54 trans_id => 0, # Default to the HEAD
56 data_sector_size => 64, # Size in bytes of each data sector
58 entries => {}, # This is the list of entries for transactions
62 # Never allow byte_size to be set directly.
63 delete $args->{byte_size};
64 if ( defined $args->{pack_size} ) {
65 if ( lc $args->{pack_size} eq 'small' ) {
66 $args->{byte_size} = 2;
68 elsif ( lc $args->{pack_size} eq 'medium' ) {
69 $args->{byte_size} = 4;
71 elsif ( lc $args->{pack_size} eq 'large' ) {
72 $args->{byte_size} = 8;
75 DBM::Deep->_throw_error( "Unknown pack_size value: '$args->{pack_size}'" );
79 # Grab the parameters we want to use
80 foreach my $param ( keys %$self ) {
81 next unless exists $args->{$param};
82 $self->{$param} = $args->{$param};
86 max_buckets => { floor => 16, ceil => 256 },
87 num_txns => { floor => 1, ceil => 255 },
88 data_sector_size => { floor => 32, ceil => 256 },
91 while ( my ($attr, $c) = each %validations ) {
92 if ( !defined $self->{$attr}
93 || !length $self->{$attr}
94 || $self->{$attr} =~ /\D/
95 || $self->{$attr} < $c->{floor}
97 $self->{$attr} = '(undef)' if !defined $self->{$attr};
98 warn "Floor of $attr is $c->{floor}. Setting it to $c->{floor} from '$self->{$attr}'\n";
99 $self->{$attr} = $c->{floor};
101 elsif ( $self->{$attr} > $c->{ceil} ) {
102 warn "Ceiling of $attr is $c->{ceil}. Setting it to $c->{ceil} from '$self->{$attr}'\n";
103 $self->{$attr} = $c->{ceil};
107 if ( !$self->{digest} ) {
109 $self->{digest} = \&Digest::MD5::md5;
115 ################################################################################
119 my ($obj, $key) = @_;
121 # This will be a Reference sector
122 my $sector = $self->_load_sector( $obj->_base_offset )
125 if ( $sector->staleness != $obj->_staleness ) {
129 my $key_md5 = $self->_apply_digest( $key );
131 my $value_sector = $sector->get_data_for({
136 unless ( $value_sector ) {
137 $value_sector = DBM::Deep::Engine::Sector::Null->new({
142 $sector->write_data({
145 value => $value_sector,
149 return $value_sector->data;
156 # This will be a Reference sector
157 my $sector = $self->_load_sector( $obj->_base_offset )
158 or DBM::Deep->_throw_error( "How did get_classname fail (no sector for '$obj')?!" );
160 if ( $sector->staleness != $obj->_staleness ) {
164 return $sector->get_classname;
169 my ($obj, $key) = @_;
171 # This will be a Reference sector
172 my $sector = $self->_load_sector( $obj->_base_offset )
175 if ( $sector->staleness != $obj->_staleness ) {
179 my $data = $sector->get_data_for({
180 key_md5 => $self->_apply_digest( $key ),
184 # exists() returns 1 or '' for true/false.
185 return $data ? 1 : '';
190 my ($obj, $key) = @_;
192 my $sector = $self->_load_sector( $obj->_base_offset )
195 if ( $sector->staleness != $obj->_staleness ) {
199 return $sector->delete_key({
200 key_md5 => $self->_apply_digest( $key ),
207 my ($obj, $key, $value) = @_;
209 my $r = Scalar::Util::reftype( $value ) || '';
212 last if $r eq 'HASH';
213 last if $r eq 'ARRAY';
215 DBM::Deep->_throw_error(
216 "Storage of references of type '$r' is not supported."
221 if ( !defined $value ) {
222 $class = 'DBM::Deep::Engine::Sector::Null';
224 elsif ( $r eq 'ARRAY' || $r eq 'HASH' ) {
225 if ( $r eq 'ARRAY' && tied(@$value) ) {
226 DBM::Deep->_throw_error( "Cannot store something that is tied." );
228 if ( $r eq 'HASH' && tied(%$value) ) {
229 DBM::Deep->_throw_error( "Cannot store something that is tied." );
231 $class = 'DBM::Deep::Engine::Sector::Reference';
232 $type = substr( $r, 0, 1 );
235 $class = 'DBM::Deep::Engine::Sector::Scalar';
238 # This will be a Reference sector
239 my $sector = $self->_load_sector( $obj->_base_offset )
240 or DBM::Deep->_throw_error( "Cannot write to a deleted spot in DBM::Deep." );
242 if ( $sector->staleness != $obj->_staleness ) {
243 DBM::Deep->_throw_error( "Cannot write to a deleted spot in DBM::Deep.n" );
246 # Create this after loading the reference sector in case something bad happens.
247 # This way, we won't allocate value sector(s) needlessly.
248 my $value_sector = $class->new({
254 $sector->write_data({
256 key_md5 => $self->_apply_digest( $key ),
257 value => $value_sector,
260 # This code is to make sure we write all the values in the $value to the disk
261 # and to make sure all changes to $value after the assignment are reflected
262 # on disk. This may be counter-intuitive at first, but it is correct dwimmery.
263 # NOTE - simply tying $value won't perform a STORE on each value. Hence, the
264 # copy to a temp value.
265 if ( $r eq 'ARRAY' ) {
267 tie @$value, 'DBM::Deep', {
268 base_offset => $value_sector->offset,
269 staleness => $value_sector->staleness,
270 storage => $self->storage,
274 bless $value, 'DBM::Deep::Array' unless Scalar::Util::blessed( $value );
276 elsif ( $r eq 'HASH' ) {
278 tie %$value, 'DBM::Deep', {
279 base_offset => $value_sector->offset,
280 staleness => $value_sector->staleness,
281 storage => $self->storage,
286 bless $value, 'DBM::Deep::Hash' unless Scalar::Util::blessed( $value );
292 # XXX Add staleness here
295 my ($obj, $prev_key) = @_;
297 # XXX Need to add logic about resetting the iterator if any key in the reference has changed
298 unless ( $prev_key ) {
299 $obj->{iterator} = DBM::Deep::Iterator->new({
300 base_offset => $obj->_base_offset,
305 return $obj->{iterator}->get_next_key( $obj );
308 ################################################################################
314 # We're opening the file.
315 unless ( $obj->_base_offset ) {
316 my $bytes_read = $self->_read_file_header;
318 # Creating a new file
319 unless ( $bytes_read ) {
320 $self->_write_file_header;
322 # 1) Create Array/Hash entry
323 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
327 $obj->{base_offset} = $initial_reference->offset;
328 $obj->{staleness} = $initial_reference->staleness;
330 $self->storage->flush;
332 # Reading from an existing file
334 $obj->{base_offset} = $bytes_read;
335 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
337 offset => $obj->_base_offset,
339 unless ( $initial_reference ) {
340 DBM::Deep->_throw_error("Corrupted file, no master index record");
343 unless ($obj->_type eq $initial_reference->type) {
344 DBM::Deep->_throw_error("File type mismatch");
347 $obj->{staleness} = $initial_reference->staleness;
358 if ( $self->trans_id ) {
359 DBM::Deep->_throw_error( "Cannot begin_work within an active transaction" );
362 my @slots = $self->read_txn_slots;
364 for my $i ( 0 .. $#slots ) {
368 $self->set_trans_id( $i + 1 );
373 DBM::Deep->_throw_error( "Cannot allocate transaction ID" );
375 $self->write_txn_slots( @slots );
377 if ( !$self->trans_id ) {
378 DBM::Deep->_throw_error( "Cannot begin_work - no available transactions" );
388 if ( !$self->trans_id ) {
389 DBM::Deep->_throw_error( "Cannot rollback without an active transaction" );
392 # Each entry is the file location for a bucket that has a modification for
393 # this transaction. The entries need to be expunged.
394 foreach my $entry (@{ $self->get_entries } ) {
395 # Remove the entry here
396 my $read_loc = $entry
400 + ($self->trans_id - 1) * ( $self->byte_size + $STALE_SIZE );
402 my $data_loc = $self->storage->read_at( $read_loc, $self->byte_size );
403 $data_loc = unpack( $StP{$self->byte_size}, $data_loc );
404 $self->storage->print_at( $read_loc, pack( $StP{$self->byte_size}, 0 ) );
406 if ( $data_loc > 1 ) {
407 $self->_load_sector( $data_loc )->free;
411 $self->clear_entries;
413 my @slots = $self->read_txn_slots;
414 $slots[$self->trans_id-1] = 0;
415 $self->write_txn_slots( @slots );
416 $self->inc_txn_staleness_counter( $self->trans_id );
417 $self->set_trans_id( 0 );
426 if ( !$self->trans_id ) {
427 DBM::Deep->_throw_error( "Cannot commit without an active transaction" );
430 foreach my $entry (@{ $self->get_entries } ) {
431 # Overwrite the entry in head with the entry in trans_id
436 my $head_loc = $self->storage->read_at( $base, $self->byte_size );
437 $head_loc = unpack( $StP{$self->byte_size}, $head_loc );
439 my $spot = $base + $self->byte_size + ($self->trans_id - 1) * ( $self->byte_size + $STALE_SIZE );
440 my $trans_loc = $self->storage->read_at(
441 $spot, $self->byte_size,
444 $self->storage->print_at( $base, $trans_loc );
445 $self->storage->print_at(
447 pack( $StP{$self->byte_size} . ' ' . $StP{$STALE_SIZE}, (0) x 2 ),
450 if ( $head_loc > 1 ) {
451 $self->_load_sector( $head_loc )->free;
455 $self->clear_entries;
457 my @slots = $self->read_txn_slots;
458 $slots[$self->trans_id-1] = 0;
459 $self->write_txn_slots( @slots );
460 $self->inc_txn_staleness_counter( $self->trans_id );
461 $self->set_trans_id( 0 );
468 my $bl = $self->txn_bitfield_len;
469 my $num_bits = $bl * 8;
470 return split '', unpack( 'b'.$num_bits,
471 $self->storage->read_at(
472 $self->trans_loc, $bl,
477 sub write_txn_slots {
479 my $num_bits = $self->txn_bitfield_len * 8;
480 $self->storage->print_at( $self->trans_loc,
481 pack( 'b'.$num_bits, join('', @_) ),
485 sub get_running_txn_ids {
487 my @transactions = $self->read_txn_slots;
488 my @trans_ids = map { $_+1} grep { $transactions[$_] } 0 .. $#transactions;
491 sub get_txn_staleness_counter {
495 # Hardcode staleness of 0 for the HEAD
496 return 0 unless $trans_id;
498 return unpack( $StP{$STALE_SIZE},
499 $self->storage->read_at(
500 $self->trans_loc + 4 + $STALE_SIZE * ($trans_id - 1),
506 sub inc_txn_staleness_counter {
510 # Hardcode staleness of 0 for the HEAD
511 return unless $trans_id;
513 $self->storage->print_at(
514 $self->trans_loc + 4 + $STALE_SIZE * ($trans_id - 1),
515 pack( $StP{$STALE_SIZE}, $self->get_txn_staleness_counter( $trans_id ) + 1 ),
521 return [ keys %{ $self->{entries}{$self->trans_id} ||= {} } ];
526 my ($trans_id, $loc) = @_;
528 $self->{entries}{$trans_id} ||= {};
529 $self->{entries}{$trans_id}{$loc} = undef;
532 # If the buckets are being relocated because of a reindexing, the entries
533 # mechanism needs to be made aware of it.
536 my ($old_loc, $new_loc) = @_;
539 while ( my ($trans_id, $locs) = each %{ $self->{entries} } ) {
540 foreach my $orig_loc ( keys %{ $locs } ) {
541 if ( $orig_loc == $old_loc ) {
542 delete $locs->{orig_loc};
543 $locs->{$new_loc} = undef;
552 delete $self->{entries}{$self->trans_id};
555 ################################################################################
558 my $header_fixed = length( SIG_FILE ) + 1 + 4 + 4;
559 my $this_file_version = 2;
561 sub _write_file_header {
564 my $nt = $self->num_txns;
565 my $bl = $self->txn_bitfield_len;
567 my $header_var = 1 + 1 + 1 + 1 + $bl + $STALE_SIZE * ($nt - 1) + 3 * $self->byte_size;
569 my $loc = $self->storage->request_space( $header_fixed + $header_var );
571 $self->storage->print_at( $loc,
574 pack('N', $this_file_version), # At this point, we're at 9 bytes
575 pack('N', $header_var), # header size
576 # --- Above is $header_fixed. Below is $header_var
577 pack('C', $self->byte_size),
579 # These shenanigans are to allow a 256 within a C
580 pack('C', $self->max_buckets - 1),
581 pack('C', $self->data_sector_size - 1),
584 pack('C' . $bl, 0 ), # Transaction activeness bitfield
585 pack($StP{$STALE_SIZE}.($nt-1), 0 x ($nt-1) ), # Transaction staleness counters
586 pack($StP{$self->byte_size}, 0), # Start of free chain (blist size)
587 pack($StP{$self->byte_size}, 0), # Start of free chain (data size)
588 pack($StP{$self->byte_size}, 0), # Start of free chain (index size)
591 #XXX Set these less fragilely
592 $self->set_trans_loc( $header_fixed + 4 );
593 $self->set_chains_loc( $header_fixed + 4 + $bl + $STALE_SIZE * ($nt-1) );
598 sub _read_file_header {
601 my $buffer = $self->storage->read_at( 0, $header_fixed );
602 return unless length($buffer);
604 my ($file_signature, $sig_header, $file_version, $size) = unpack(
608 unless ( $file_signature eq SIG_FILE ) {
609 $self->storage->close;
610 DBM::Deep->_throw_error( "Signature not found -- file is not a Deep DB" );
613 unless ( $sig_header eq SIG_HEADER ) {
614 $self->storage->close;
615 DBM::Deep->_throw_error( "Pre-1.00 file version found" );
618 unless ( $file_version == $this_file_version ) {
619 $self->storage->close;
620 DBM::Deep->_throw_error(
621 "Wrong file version found - " . $file_version .
622 " - expected " . $this_file_version
626 my $buffer2 = $self->storage->read_at( undef, $size );
627 my @values = unpack( 'C C C C', $buffer2 );
629 if ( @values != 4 || grep { !defined } @values ) {
630 $self->storage->close;
631 DBM::Deep->_throw_error("Corrupted file - bad header");
634 #XXX Add warnings if values weren't set right
635 @{$self}{qw(byte_size max_buckets data_sector_size num_txns)} = @values;
637 # These shenangians are to allow a 256 within a C
638 $self->{max_buckets} += 1;
639 $self->{data_sector_size} += 1;
641 my $bl = $self->txn_bitfield_len;
643 my $header_var = scalar(@values) + $bl + $STALE_SIZE * ($self->num_txns - 1) + 3 * $self->byte_size;
644 unless ( $size == $header_var ) {
645 $self->storage->close;
646 DBM::Deep->_throw_error( "Unexpected size found ($size <-> $header_var)." );
649 $self->set_trans_loc( $header_fixed + scalar(@values) );
650 $self->set_chains_loc( $header_fixed + scalar(@values) + $bl + $STALE_SIZE * ($self->num_txns - 1) );
652 return length($buffer) + length($buffer2);
660 # Add a catch for offset of 0 or 1
661 return if $offset <= 1;
663 my $type = $self->storage->read_at( $offset, 1 );
664 return if $type eq chr(0);
666 if ( $type eq $self->SIG_ARRAY || $type eq $self->SIG_HASH ) {
667 return DBM::Deep::Engine::Sector::Reference->new({
673 # XXX Don't we need key_md5 here?
674 elsif ( $type eq $self->SIG_BLIST ) {
675 return DBM::Deep::Engine::Sector::BucketList->new({
681 elsif ( $type eq $self->SIG_INDEX ) {
682 return DBM::Deep::Engine::Sector::Index->new({
688 elsif ( $type eq $self->SIG_NULL ) {
689 return DBM::Deep::Engine::Sector::Null->new({
695 elsif ( $type eq $self->SIG_DATA ) {
696 return DBM::Deep::Engine::Sector::Scalar->new({
702 # This was deleted from under us, so just return and let the caller figure it out.
703 elsif ( $type eq $self->SIG_FREE ) {
707 DBM::Deep->_throw_error( "'$offset': Don't know what to do with type '$type'" );
712 return $self->{digest}->(@_);
715 sub _add_free_blist_sector { shift->_add_free_sector( 0, @_ ) }
716 sub _add_free_data_sector { shift->_add_free_sector( 1, @_ ) }
717 sub _add_free_index_sector { shift->_add_free_sector( 2, @_ ) }
719 sub _add_free_sector {
721 my ($multiple, $offset, $size) = @_;
723 my $chains_offset = $multiple * $self->byte_size;
725 my $storage = $self->storage;
727 # Increment staleness.
728 # XXX Can this increment+modulo be done by "&= 0x1" ?
729 my $staleness = unpack( $StP{$STALE_SIZE}, $storage->read_at( $offset + SIG_SIZE, $STALE_SIZE ) );
730 $staleness = ($staleness + 1 ) % ( 2 ** ( 8 * $STALE_SIZE ) );
731 $storage->print_at( $offset + SIG_SIZE, pack( $StP{$STALE_SIZE}, $staleness ) );
733 my $old_head = $storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
735 $storage->print_at( $self->chains_loc + $chains_offset,
736 pack( $StP{$self->byte_size}, $offset ),
739 # Record the old head in the new sector after the signature and staleness counter
740 $storage->print_at( $offset + SIG_SIZE + $STALE_SIZE, $old_head );
743 sub _request_blist_sector { shift->_request_sector( 0, @_ ) }
744 sub _request_data_sector { shift->_request_sector( 1, @_ ) }
745 sub _request_index_sector { shift->_request_sector( 2, @_ ) }
747 sub _request_sector {
749 my ($multiple, $size) = @_;
751 my $chains_offset = $multiple * $self->byte_size;
753 my $old_head = $self->storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
754 my $loc = unpack( $StP{$self->byte_size}, $old_head );
756 # We don't have any free sectors of the right size, so allocate a new one.
758 my $offset = $self->storage->request_space( $size );
760 # Zero out the new sector. This also guarantees correct increases
762 $self->storage->print_at( $offset, chr(0) x $size );
767 # Read the new head after the signature and the staleness counter
768 my $new_head = $self->storage->read_at( $loc + SIG_SIZE + $STALE_SIZE, $self->byte_size );
769 $self->storage->print_at( $self->chains_loc + $chains_offset, $new_head );
770 $self->storage->print_at(
771 $loc + SIG_SIZE + $STALE_SIZE,
772 pack( $StP{$self->byte_size}, 0 ),
778 ################################################################################
780 sub storage { $_[0]{storage} }
781 sub byte_size { $_[0]{byte_size} }
782 sub hash_size { $_[0]{hash_size} }
783 sub hash_chars { $_[0]{hash_chars} }
784 sub num_txns { $_[0]{num_txns} }
785 sub max_buckets { $_[0]{max_buckets} }
786 sub blank_md5 { chr(0) x $_[0]->hash_size }
787 sub data_sector_size { $_[0]{data_sector_size} }
789 # This is a calculated value
790 sub txn_bitfield_len {
792 unless ( exists $self->{txn_bitfield_len} ) {
793 my $temp = ($self->num_txns) / 8;
794 if ( $temp > int( $temp ) ) {
795 $temp = int( $temp ) + 1;
797 $self->{txn_bitfield_len} = $temp;
799 return $self->{txn_bitfield_len};
802 sub trans_id { $_[0]{trans_id} }
803 sub set_trans_id { $_[0]{trans_id} = $_[1] }
805 sub trans_loc { $_[0]{trans_loc} }
806 sub set_trans_loc { $_[0]{trans_loc} = $_[1] }
808 sub chains_loc { $_[0]{chains_loc} }
809 sub set_chains_loc { $_[0]{chains_loc} = $_[1] }
811 ################################################################################
813 package DBM::Deep::Iterator;
821 engine => $args->{engine},
822 base_offset => $args->{base_offset},
825 Scalar::Util::weaken( $self->{engine} );
830 sub reset { $_[0]{breadcrumbs} = [] }
832 sub get_sector_iterator {
836 my $sector = $self->{engine}->_load_sector( $loc )
839 if ( $sector->isa( 'DBM::Deep::Engine::Sector::Index' ) ) {
840 return DBM::Deep::Iterator::Index->new({
845 elsif ( $sector->isa( 'DBM::Deep::Engine::Sector::BucketList' ) ) {
846 return DBM::Deep::Iterator::BucketList->new({
852 DBM::Deep->_throw_error( "get_sector_iterator(): Why did $loc make a $sector?" );
859 my $crumbs = $self->{breadcrumbs};
860 my $e = $self->{engine};
862 unless ( @$crumbs ) {
863 # This will be a Reference sector
864 my $sector = $e->_load_sector( $self->{base_offset} )
865 # If no sector is found, thist must have been deleted from under us.
868 if ( $sector->staleness != $obj->_staleness ) {
872 my $loc = $sector->get_blist_loc
875 push @$crumbs, $self->get_sector_iterator( $loc );
880 unless ( @$crumbs ) {
885 my $iterator = $crumbs->[-1];
887 # This level is done.
888 if ( $iterator->at_end ) {
893 if ( $iterator->isa( 'DBM::Deep::Iterator::Index' ) ) {
894 # If we don't have any more, it will be caught at the
896 if ( my $next = $iterator->get_next_iterator ) {
897 push @$crumbs, $next;
902 unless ( $iterator->isa( 'DBM::Deep::Iterator::BucketList' ) ) {
903 DBM::Deep->_throw_error(
904 "Should have a bucketlist iterator here - instead have $iterator"
908 # At this point, we have a BucketList iterator
909 my $key = $iterator->get_next_key;
910 if ( defined $key ) {
913 #XXX else { $iterator->set_to_end() } ?
915 # We hit the end of the bucketlist iterator, so redo
919 DBM::Deep->_throw_error( "get_next_key(): How did we get here?" );
922 package DBM::Deep::Iterator::Index;
925 my $self = bless $_[1] => $_[0];
926 $self->{curr_index} = 0;
932 return $self->{curr_index} >= $self->{iterator}{engine}->hash_chars;
935 sub get_next_iterator {
940 return if $self->at_end;
941 $loc = $self->{sector}->get_entry( $self->{curr_index}++ );
944 return $self->{iterator}->get_sector_iterator( $loc );
947 package DBM::Deep::Iterator::BucketList;
950 my $self = bless $_[1] => $_[0];
951 $self->{curr_index} = 0;
957 return $self->{curr_index} >= $self->{iterator}{engine}->max_buckets;
963 return if $self->at_end;
965 my $idx = $self->{curr_index}++;
967 my $data_loc = $self->{sector}->get_data_location_for({
972 #XXX Do we want to add corruption checks here?
973 return $self->{sector}->get_key_for( $idx )->data;
976 package DBM::Deep::Engine::Sector;
979 my $self = bless $_[1], $_[0];
980 Scalar::Util::weaken( $self->{engine} );
986 #sub clone { DBM::Deep->_throw_error( "Must be implemented in the child class" ); }
988 sub engine { $_[0]{engine} }
989 sub offset { $_[0]{offset} }
990 sub type { $_[0]{type} }
994 return $self->engine->SIG_SIZE + $STALE_SIZE;
1000 my $e = $self->engine;
1002 $e->storage->print_at( $self->offset, $e->SIG_FREE );
1003 # Skip staleness counter
1004 $e->storage->print_at( $self->offset + $self->base_size,
1005 chr(0) x ($self->size - $self->base_size),
1008 my $free_meth = $self->free_meth;
1009 $e->$free_meth( $self->offset, $self->size );
1014 package DBM::Deep::Engine::Sector::Data;
1016 our @ISA = qw( DBM::Deep::Engine::Sector );
1019 sub size { $_[0]{engine}->data_sector_size }
1020 sub free_meth { return '_add_free_data_sector' }
1024 return ref($self)->new({
1025 engine => $self->engine,
1026 type => $self->type,
1027 data => $self->data,
1031 package DBM::Deep::Engine::Sector::Scalar;
1033 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1038 my $chain_loc = $self->chain_loc;
1040 $self->SUPER::free();
1043 $self->engine->_load_sector( $chain_loc )->free;
1049 sub type { $_[0]{engine}->SIG_DATA }
1053 my $engine = $self->engine;
1055 unless ( $self->offset ) {
1056 my $data_section = $self->size - $self->base_size - $engine->byte_size - 1;
1058 $self->{offset} = $engine->_request_data_sector( $self->size );
1060 my $data = delete $self->{data};
1061 my $dlen = length $data;
1063 my $curr_offset = $self->offset;
1064 while ( $continue ) {
1066 my $next_offset = 0;
1068 my ($leftover, $this_len, $chunk);
1069 if ( $dlen > $data_section ) {
1071 $this_len = $data_section;
1072 $chunk = substr( $data, 0, $this_len );
1074 $dlen -= $data_section;
1075 $next_offset = $engine->_request_data_sector( $self->size );
1076 $data = substr( $data, $this_len );
1079 $leftover = $data_section - $dlen;
1086 $engine->storage->print_at( $curr_offset, $self->type ); # Sector type
1088 $engine->storage->print_at( $curr_offset + $self->base_size,
1089 pack( $StP{$engine->byte_size}, $next_offset ), # Chain loc
1090 pack( $StP{1}, $this_len ), # Data length
1091 $chunk, # Data to be stored in this sector
1092 chr(0) x $leftover, # Zero-fill the rest
1095 $curr_offset = $next_offset;
1105 my $buffer = $self->engine->storage->read_at(
1106 $self->offset + $self->base_size + $self->engine->byte_size, 1
1109 return unpack( $StP{1}, $buffer );
1115 $StP{$self->engine->byte_size},
1116 $self->engine->storage->read_at(
1117 $self->offset + $self->base_size,
1118 $self->engine->byte_size,
1128 my $chain_loc = $self->chain_loc;
1130 $data .= $self->engine->storage->read_at(
1131 $self->offset + $self->base_size + $self->engine->byte_size + 1, $self->data_length,
1134 last unless $chain_loc;
1136 $self = $self->engine->_load_sector( $chain_loc );
1142 package DBM::Deep::Engine::Sector::Null;
1144 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1146 sub type { $_[0]{engine}->SIG_NULL }
1147 sub data_length { 0 }
1153 my $engine = $self->engine;
1155 unless ( $self->offset ) {
1156 my $leftover = $self->size - $self->base_size - 1 * $engine->byte_size - 1;
1158 $self->{offset} = $engine->_request_data_sector( $self->size );
1159 $engine->storage->print_at( $self->offset, $self->type ); # Sector type
1160 # Skip staleness counter
1161 $engine->storage->print_at( $self->offset + $self->base_size,
1162 pack( $StP{$engine->byte_size}, 0 ), # Chain loc
1163 pack( $StP{1}, $self->data_length ), # Data length
1164 chr(0) x $leftover, # Zero-fill the rest
1171 package DBM::Deep::Engine::Sector::Reference;
1173 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1178 my $e = $self->engine;
1180 unless ( $self->offset ) {
1181 my $classname = Scalar::Util::blessed( delete $self->{data} );
1182 my $leftover = $self->size - $self->base_size - 2 * $e->byte_size;
1184 my $class_offset = 0;
1185 if ( defined $classname ) {
1186 my $class_sector = DBM::Deep::Engine::Sector::Scalar->new({
1190 $class_offset = $class_sector->offset;
1193 $self->{offset} = $e->_request_data_sector( $self->size );
1194 $e->storage->print_at( $self->offset, $self->type ); # Sector type
1195 # Skip staleness counter
1196 $e->storage->print_at( $self->offset + $self->base_size,
1197 pack( $StP{$e->byte_size}, 0 ), # Index/BList loc
1198 pack( $StP{$e->byte_size}, $class_offset ), # Classname loc
1199 chr(0) x $leftover, # Zero-fill the rest
1203 $self->{type} = $e->storage->read_at( $self->offset, 1 );
1206 $self->{staleness} = unpack(
1208 $e->storage->read_at( $self->offset + $e->SIG_SIZE, $STALE_SIZE ),
1217 my $blist_loc = $self->get_blist_loc;
1218 $self->engine->_load_sector( $blist_loc )->free if $blist_loc;
1220 my $class_loc = $self->get_class_offset;
1221 $self->engine->_load_sector( $class_loc )->free if $class_loc;
1223 $self->SUPER::free();
1226 sub staleness { $_[0]{staleness} }
1232 # Assume that the head is not allowed unless otherwise specified.
1233 $args->{allow_head} = 0 unless exists $args->{allow_head};
1235 # Assume we don't create a new blist location unless otherwise specified.
1236 $args->{create} = 0 unless exists $args->{create};
1238 my $blist = $self->get_bucket_list({
1239 key_md5 => $args->{key_md5},
1240 key => $args->{key},
1241 create => $args->{create},
1243 return unless $blist && $blist->{found};
1245 # At this point, $blist knows where the md5 is. What it -doesn't- know yet
1246 # is whether or not this transaction has this key. That's part of the next
1248 my $location = $blist->get_data_location_for({
1249 allow_head => $args->{allow_head},
1252 return $self->engine->_load_sector( $location );
1259 my $blist = $self->get_bucket_list({
1260 key_md5 => $args->{key_md5},
1261 key => $args->{key},
1263 }) or DBM::Deep->_throw_error( "How did write_data fail (no blist)?!" );
1265 # Handle any transactional bookkeeping.
1266 if ( $self->engine->trans_id ) {
1267 if ( ! $blist->has_md5 ) {
1268 $blist->mark_deleted({
1274 my @trans_ids = $self->engine->get_running_txn_ids;
1275 if ( $blist->has_md5 ) {
1277 my $old_value = $blist->get_data_for;
1278 foreach my $other_trans_id ( @trans_ids ) {
1279 next if $blist->get_data_location_for({
1280 trans_id => $other_trans_id,
1284 trans_id => $other_trans_id,
1285 key => $args->{key},
1286 key_md5 => $args->{key_md5},
1287 value => $old_value->clone,
1294 foreach my $other_trans_id ( @trans_ids ) {
1295 #XXX This doesn't seem to possible to ever happen . . .
1296 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1297 $blist->mark_deleted({
1298 trans_id => $other_trans_id,
1305 #XXX Is this safe to do transactionally?
1306 # Free the place we're about to write to.
1307 if ( $blist->get_data_location_for({ allow_head => 0 }) ) {
1308 $blist->get_data_for({ allow_head => 0 })->free;
1312 key => $args->{key},
1313 key_md5 => $args->{key_md5},
1314 value => $args->{value},
1322 # XXX What should happen if this fails?
1323 my $blist = $self->get_bucket_list({
1324 key_md5 => $args->{key_md5},
1325 }) or DBM::Deep->_throw_error( "How did delete_key fail (no blist)?!" );
1327 # Save the location so that we can free the data
1328 my $location = $blist->get_data_location_for({
1331 my $old_value = $location && $self->engine->_load_sector( $location );
1333 my @trans_ids = $self->engine->get_running_txn_ids;
1335 if ( $self->engine->trans_id == 0 ) {
1337 foreach my $other_trans_id ( @trans_ids ) {
1338 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1340 trans_id => $other_trans_id,
1341 key => $args->{key},
1342 key_md5 => $args->{key_md5},
1343 value => $old_value->clone,
1351 $blist->mark_deleted( $args );
1354 $data = $old_value->data;
1359 $data = $blist->delete_md5( $args );
1368 my $e = $self->engine;
1369 my $blist_loc = $e->storage->read_at( $self->offset + $self->base_size, $e->byte_size );
1370 return unpack( $StP{$e->byte_size}, $blist_loc );
1373 sub get_bucket_list {
1378 # XXX Add in check here for recycling?
1380 my $engine = $self->engine;
1382 my $blist_loc = $self->get_blist_loc;
1384 # There's no index or blist yet
1385 unless ( $blist_loc ) {
1386 return unless $args->{create};
1388 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1390 key_md5 => $args->{key_md5},
1393 $engine->storage->print_at( $self->offset + $self->base_size,
1394 pack( $StP{$engine->byte_size}, $blist->offset ),
1400 my $sector = $engine->_load_sector( $blist_loc )
1401 or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
1403 my $last_sector = undef;
1404 while ( $sector->isa( 'DBM::Deep::Engine::Sector::Index' ) ) {
1405 $blist_loc = $sector->get_entry( ord( substr( $args->{key_md5}, $i++, 1 ) ) );
1406 $last_sector = $sector;
1408 $sector = $engine->_load_sector( $blist_loc )
1409 or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
1417 # This means we went through the Index sector(s) and found an empty slot
1418 unless ( $sector ) {
1419 return unless $args->{create};
1421 DBM::Deep->_throw_error( "No last_sector when attempting to build a new entry" )
1422 unless $last_sector;
1424 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1426 key_md5 => $args->{key_md5},
1429 $last_sector->set_entry( ord( substr( $args->{key_md5}, $i - 1, 1 ) ) => $blist->offset );
1434 $sector->find_md5( $args->{key_md5} );
1436 # See whether or not we need to reindex the bucketlist
1437 if ( !$sector->has_md5 && $args->{create} && $sector->{idx} == -1 ) {
1438 my $new_index = DBM::Deep::Engine::Sector::Index->new({
1443 #XXX q.v. the comments for this function.
1444 foreach my $entry ( $sector->chopped_up ) {
1445 my ($spot, $md5) = @{$entry};
1446 my $idx = ord( substr( $md5, $i, 1 ) );
1448 # XXX This is inefficient
1449 my $blist = $blist_cache{$idx}
1450 ||= DBM::Deep::Engine::Sector::BucketList->new({
1454 $new_index->set_entry( $idx => $blist->offset );
1456 my $new_spot = $blist->write_at_next_open( $md5 );
1457 $engine->reindex_entry( $spot => $new_spot );
1460 # Handle the new item separately.
1462 my $idx = ord( substr( $args->{key_md5}, $i, 1 ) );
1463 my $blist = $blist_cache{$idx}
1464 ||= DBM::Deep::Engine::Sector::BucketList->new({
1468 $new_index->set_entry( $idx => $blist->offset );
1471 $blist->find_md5( $args->{key_md5} );
1473 key => $args->{key},
1474 key_md5 => $args->{key_md5},
1475 value => DBM::Deep::Engine::Sector::Null->new({
1482 if ( $last_sector ) {
1483 $last_sector->set_entry(
1484 ord( substr( $args->{key_md5}, $i - 1, 1 ) ),
1488 $engine->storage->print_at( $self->offset + $self->base_size,
1489 pack( $StP{$engine->byte_size}, $new_index->offset ),
1495 $sector = $blist_cache{ ord( substr( $args->{key_md5}, $i, 1 ) ) };
1496 $sector->find_md5( $args->{key_md5} );
1502 sub get_class_offset {
1505 my $e = $self->engine;
1507 $StP{$e->byte_size},
1508 $e->storage->read_at(
1509 $self->offset + $self->base_size + 1 * $e->byte_size, $e->byte_size,
1517 my $class_offset = $self->get_class_offset;
1519 return unless $class_offset;
1521 return $self->engine->_load_sector( $class_offset )->data;
1524 #XXX Add singleton handling here
1528 my $new_obj = DBM::Deep->new({
1529 type => $self->type,
1530 base_offset => $self->offset,
1531 staleness => $self->staleness,
1532 storage => $self->engine->storage,
1533 engine => $self->engine,
1536 if ( $self->engine->storage->{autobless} ) {
1537 my $classname = $self->get_classname;
1538 if ( defined $classname ) {
1539 bless $new_obj, $classname;
1546 package DBM::Deep::Engine::Sector::BucketList;
1548 our @ISA = qw( DBM::Deep::Engine::Sector );
1553 my $engine = $self->engine;
1555 unless ( $self->offset ) {
1556 my $leftover = $self->size - $self->base_size;
1558 $self->{offset} = $engine->_request_blist_sector( $self->size );
1559 $engine->storage->print_at( $self->offset, $engine->SIG_BLIST ); # Sector type
1560 # Skip staleness counter
1561 $engine->storage->print_at( $self->offset + $self->base_size,
1562 chr(0) x $leftover, # Zero-fill the data
1566 if ( $self->{key_md5} ) {
1575 unless ( $self->{size} ) {
1576 my $e = $self->engine;
1577 # Base + numbuckets * bucketsize
1578 $self->{size} = $self->base_size + $e->max_buckets * $self->bucket_size;
1580 return $self->{size};
1583 sub free_meth { return '_add_free_blist_sector' }
1587 unless ( $self->{bucket_size} ) {
1588 my $e = $self->engine;
1589 # Key + head (location) + transactions (location + staleness-counter)
1590 my $location_size = $e->byte_size + $e->byte_size + ($e->num_txns - 1) * ($e->byte_size + $STALE_SIZE);
1591 $self->{bucket_size} = $e->hash_size + $location_size;
1593 return $self->{bucket_size};
1596 # XXX This is such a poor hack. I need to rethink this code.
1600 my $e = $self->engine;
1603 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
1604 my $spot = $self->offset + $self->base_size + $idx * $self->bucket_size;
1605 my $md5 = $e->storage->read_at( $spot, $e->hash_size );
1607 #XXX If we're chopping, why would we ever have the blank_md5?
1608 last if $md5 eq $e->blank_md5;
1610 my $rest = $e->storage->read_at( undef, $self->bucket_size - $e->hash_size );
1611 push @buckets, [ $spot, $md5 . $rest ];
1617 sub write_at_next_open {
1621 #XXX This is such a hack!
1622 $self->{_next_open} = 0 unless exists $self->{_next_open};
1624 my $spot = $self->offset + $self->base_size + $self->{_next_open}++ * $self->bucket_size;
1625 $self->engine->storage->print_at( $spot, $entry );
1632 unless ( exists $self->{found} ) {
1635 return $self->{found};
1641 $self->{found} = undef;
1645 $self->{key_md5} = shift;
1648 # If we don't have an MD5, then what are we supposed to do?
1649 unless ( exists $self->{key_md5} ) {
1650 DBM::Deep->_throw_error( "Cannot find_md5 without a key_md5 set" );
1653 my $e = $self->engine;
1654 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
1655 my $potential = $e->storage->read_at(
1656 $self->offset + $self->base_size + $idx * $self->bucket_size, $e->hash_size,
1659 if ( $potential eq $e->blank_md5 ) {
1660 $self->{idx} = $idx;
1664 if ( $potential eq $self->{key_md5} ) {
1666 $self->{idx} = $idx;
1678 DBM::Deep->_throw_error( "write_md5: no key" ) unless exists $args->{key};
1679 DBM::Deep->_throw_error( "write_md5: no key_md5" ) unless exists $args->{key_md5};
1680 DBM::Deep->_throw_error( "write_md5: no value" ) unless exists $args->{value};
1682 my $engine = $self->engine;
1684 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
1686 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1687 $engine->add_entry( $args->{trans_id}, $spot );
1689 unless ($self->{found}) {
1690 my $key_sector = DBM::Deep::Engine::Sector::Scalar->new({
1692 data => $args->{key},
1695 $engine->storage->print_at( $spot,
1697 pack( $StP{$engine->byte_size}, $key_sector->offset ),
1702 + $engine->hash_size
1703 + $engine->byte_size;
1705 if ( $args->{trans_id} ) {
1706 $loc += $engine->byte_size + ($args->{trans_id} - 1) * ( $engine->byte_size + $STALE_SIZE );
1708 $engine->storage->print_at( $loc,
1709 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
1710 pack( $StP{$STALE_SIZE}, $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
1714 $engine->storage->print_at( $loc,
1715 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
1725 my $engine = $self->engine;
1727 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
1729 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1730 $engine->add_entry( $args->{trans_id}, $spot );
1733 + $engine->hash_size
1734 + $engine->byte_size;
1736 if ( $args->{trans_id} ) {
1737 $loc += $engine->byte_size + ($args->{trans_id} - 1) * ( $engine->byte_size + $STALE_SIZE );
1739 $engine->storage->print_at( $loc,
1740 pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
1741 pack( $StP{$STALE_SIZE}, $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
1745 $engine->storage->print_at( $loc,
1746 pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
1756 my $engine = $self->engine;
1757 return undef unless $self->{found};
1759 # Save the location so that we can free the data
1760 my $location = $self->get_data_location_for({
1763 my $key_sector = $self->get_key_for;
1765 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1766 $engine->storage->print_at( $spot,
1767 $engine->storage->read_at(
1768 $spot + $self->bucket_size,
1769 $self->bucket_size * ( $engine->max_buckets - $self->{idx} - 1 ),
1771 chr(0) x $self->bucket_size,
1776 my $data_sector = $self->engine->_load_sector( $location );
1777 my $data = $data_sector->data;
1783 sub get_data_location_for {
1788 $args->{allow_head} = 0 unless exists $args->{allow_head};
1789 $args->{trans_id} = $self->engine->trans_id unless exists $args->{trans_id};
1790 $args->{idx} = $self->{idx} unless exists $args->{idx};
1792 my $e = $self->engine;
1794 my $spot = $self->offset + $self->base_size
1795 + $args->{idx} * $self->bucket_size
1799 if ( $args->{trans_id} ) {
1800 $spot += $e->byte_size + ($args->{trans_id} - 1) * ( $e->byte_size + $STALE_SIZE );
1803 my $buffer = $e->storage->read_at(
1805 $e->byte_size + $STALE_SIZE,
1807 my ($loc, $staleness) = unpack( $StP{$e->byte_size} . ' ' . $StP{$STALE_SIZE}, $buffer );
1809 if ( $args->{trans_id} ) {
1810 # We have found an entry that is old, so get rid of it
1811 if ( $staleness != (my $s = $e->get_txn_staleness_counter( $args->{trans_id} ) ) ) {
1812 $e->storage->print_at(
1814 pack( $StP{$e->byte_size} . ' ' . $StP{$STALE_SIZE}, (0) x 2 ),
1820 # If we're in a transaction and we never wrote to this location, try the
1822 if ( $args->{trans_id} && !$loc && $args->{allow_head} ) {
1823 return $self->get_data_location_for({
1826 idx => $args->{idx},
1829 return $loc <= 1 ? 0 : $loc;
1837 return unless $self->{found};
1838 my $location = $self->get_data_location_for({
1839 allow_head => $args->{allow_head},
1841 return $self->engine->_load_sector( $location );
1847 $idx = $self->{idx} unless defined $idx;
1849 if ( $idx >= $self->engine->max_buckets ) {
1850 DBM::Deep->_throw_error( "get_key_for(): Attempting to retrieve $idx" );
1853 my $location = $self->engine->storage->read_at(
1854 $self->offset + $self->base_size + $idx * $self->bucket_size + $self->engine->hash_size,
1855 $self->engine->byte_size,
1857 $location = unpack( $StP{$self->engine->byte_size}, $location );
1858 DBM::Deep->_throw_error( "get_key_for: No location?" ) unless $location;
1860 return $self->engine->_load_sector( $location );
1863 package DBM::Deep::Engine::Sector::Index;
1865 our @ISA = qw( DBM::Deep::Engine::Sector );
1870 my $engine = $self->engine;
1872 unless ( $self->offset ) {
1873 my $leftover = $self->size - $self->base_size;
1875 $self->{offset} = $engine->_request_index_sector( $self->size );
1876 $engine->storage->print_at( $self->offset, $engine->SIG_INDEX ); # Sector type
1877 # Skip staleness counter
1878 $engine->storage->print_at( $self->offset + $self->base_size,
1879 chr(0) x $leftover, # Zero-fill the rest
1889 unless ( $self->{size} ) {
1890 my $e = $self->engine;
1891 $self->{size} = $self->base_size + $e->byte_size * $e->hash_chars;
1893 return $self->{size};
1896 sub free_meth { return '_add_free_index_sector' }
1900 my $e = $self->engine;
1902 for my $i ( 0 .. $e->hash_chars - 1 ) {
1903 my $l = $self->get_entry( $i ) or next;
1904 $e->_load_sector( $l )->free;
1907 $self->SUPER::free();
1913 return $self->offset + $self->base_size + $idx * $self->engine->byte_size;
1920 my $e = $self->engine;
1922 DBM::Deep->_throw_error( "get_entry: Out of range ($idx)" )
1923 if $idx < 0 || $idx >= $e->hash_chars;
1926 $StP{$e->byte_size},
1927 $e->storage->read_at( $self->_loc_for( $idx ), $e->byte_size ),
1933 my ($idx, $loc) = @_;
1935 my $e = $self->engine;
1937 DBM::Deep->_throw_error( "set_entry: Out of range ($idx)" )
1938 if $idx < 0 || $idx >= $e->hash_chars;
1940 $self->engine->storage->print_at(
1941 $self->_loc_for( $idx ),
1942 pack( $StP{$e->byte_size}, $loc ),