Commit | Line | Data |
fb451ba6 |
1 | package DBM::Deep::Engine2; |
2 | |
3 | use base 'DBM::Deep::Engine'; |
4 | |
5 | use 5.6.0; |
6 | |
7 | use strict; |
8 | use warnings; |
9 | |
10 | our $VERSION = q(0.99_03); |
11 | |
12 | use Fcntl qw( :DEFAULT :flock ); |
13 | use Scalar::Util (); |
14 | |
15 | # File-wide notes: |
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 |
19 | # been done. |
20 | |
21 | # Setup file and tag signatures. These should never change. |
22 | sub SIG_FILE () { 'DPDB' } |
23 | sub SIG_HEADER () { 'h' } |
24 | sub SIG_INTERNAL () { 'i' } |
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' } |
32 | sub SIG_KEYS () { 'K' } |
33 | sub SIG_SIZE () { 1 } |
34 | |
35 | # This is the transaction ID for the HEAD |
36 | sub HEAD () { 0 } |
37 | |
38 | sub read_value { |
39 | my $self = shift; |
40 | my ($trans_id, $base_offset, $key) = @_; |
41 | |
42 | my ($_val_offset, $_is_del) = $self->_find_value_offset({ |
43 | offset => $base_offset, |
44 | trans_id => $trans_id, |
45 | allow_head => 1, |
46 | }); |
47 | die "Attempt to use a deleted value" if $_is_del; |
48 | die "Internal error!" if !$_val_offset; |
49 | |
50 | my ($key_offset) = $self->_find_key_offset({ |
51 | offset => $_val_offset, |
52 | key_md5 => $self->_apply_digest( $key ), |
53 | }); |
54 | return if !$key_offset; |
55 | |
56 | my ($val_offset, $is_del) = $self->_find_value_offset({ |
57 | offset => $key_offset, |
58 | trans_id => $trans_id, |
59 | allow_head => 1, |
60 | }); |
61 | return if $is_del; |
62 | die "Internal error!" if !$val_offset; |
63 | |
64 | return $self->_read_value({ |
65 | offset => $val_offset, |
66 | }); |
67 | } |
68 | |
69 | sub key_exists { |
70 | my $self = shift; |
71 | my ($trans_id, $base_offset, $key) = @_; |
72 | |
73 | my ($_val_offset, $_is_del) = $self->_find_value_offset({ |
74 | offset => $base_offset, |
75 | trans_id => $trans_id, |
76 | allow_head => 1, |
77 | }); |
78 | die "Attempt to use a deleted value" if $_is_del; |
79 | die "Internal error!" if !$_val_offset; |
80 | |
81 | my ($key_offset) = $self->_find_key_offset({ |
82 | offset => $_val_offset, |
83 | key_md5 => $self->_apply_digest( $key ), |
84 | }); |
85 | return if !$key_offset; |
86 | |
87 | my ($val_offset, $is_del) = $self->_find_value_offset({ |
88 | offset => $key_offset, |
89 | trans_id => $trans_id, |
90 | allow_head => 1, |
91 | }); |
92 | |
93 | return 1 if $is_del; |
94 | |
95 | die "Internal error!" if !$_val_offset; |
96 | return ''; |
97 | } |
98 | |
99 | sub get_next_key { |
100 | my $self = shift; |
101 | my ($offset) = @_; |
102 | |
103 | # If the previous key was not specifed, start at the top and |
104 | # return the first one found. |
105 | my $temp; |
106 | if ( @_ > 1 ) { |
107 | $temp = { |
108 | prev_md5 => $self->apply_digest($_[1]), |
109 | return_next => 0, |
110 | }; |
111 | } |
112 | else { |
113 | $temp = { |
114 | prev_md5 => chr(0) x $self->{hash_size}, |
115 | return_next => 1, |
116 | }; |
117 | } |
118 | |
119 | return $self->traverse_index( $temp, $offset, 0 ); |
120 | } |
121 | |
122 | sub delete_key { |
123 | my $self = shift; |
124 | my ($trans_id, $base_offset, $key) = @_; |
125 | |
126 | my ($_val_offset, $_is_del) = $self->_find_value_offset({ |
127 | offset => $base_offset, |
128 | trans_id => $trans_id, |
129 | allow_head => 1, |
130 | }); |
131 | die "Attempt to use a deleted value" if $_is_del; |
132 | die "Internal error!" if !$_val_offset; |
133 | |
134 | my ($key_offset, $bucket_tag) = $self->_find_key_offset({ |
135 | offset => $_val_offset, |
136 | key_md5 => $self->_apply_digest( $key ), |
137 | }); |
138 | return if !$key_offset; |
139 | |
140 | my $key_tag = $self->load_tag( $key_offset ); |
141 | |
142 | if ( $trans_id ) { |
143 | $self->_mark_as_deleted({ |
144 | tag => $key_tag, |
145 | trans_id => $trans_id, |
146 | }); |
147 | } |
148 | else { |
149 | my $value = $self->read_value( $trans_id, $base_offset, $key ); |
150 | if ( my @transactions = $self->_storage->current_transactions ) { |
151 | foreach my $other_trans_id ( @transactions ) { |
152 | next if $self->_has_keyloc_entry({ |
153 | tag => $key_tag, |
154 | trans_id => $other_trans_id, |
155 | }); |
156 | $self->write_value( $other_trans_id, $base_offset, $key, $value ); |
157 | } |
158 | } |
159 | else { |
160 | $self->_remove_key_offset({ |
161 | offset => $_val_offset, |
162 | key_md5 => $self->_apply_digest( $key ), |
163 | }); |
164 | } |
165 | } |
166 | |
167 | return 1; |
168 | } |
169 | |
170 | sub write_value { |
171 | my $self = shift; |
172 | my ($trans_id, $base_offset, $key, $value) = @_; |
173 | |
174 | # This verifies that only supported values will be stored. |
175 | { |
176 | my $r = Scalar::Util::reftype( $value ); |
177 | |
178 | last if !defined $r; |
179 | last if $r eq 'HASH'; |
180 | last if $r eq 'ARRAY'; |
181 | |
182 | $self->_throw_error( |
183 | "Storage of references of type '$r' is not supported." |
184 | ); |
185 | } |
186 | |
187 | my ($_val_offset, $_is_del) = $self->_find_value_offset({ |
188 | offset => $base_offset, |
189 | trans_id => $trans_id, |
190 | allow_head => 1, |
191 | }); |
192 | die "Attempt to use a deleted value" if $_is_del; |
193 | die "Internal error!" if !$_val_offset; |
194 | |
195 | my ($key_offset, $bucket_tag) = $self->_find_key_offset({ |
196 | offset => $_val_offset, |
197 | key_md5 => $self->_apply_digest( $key ), |
198 | create => 1, |
199 | }); |
200 | die "Cannot find/create new key offset!" if !$key_offset; |
201 | |
202 | my $key_tag = $self->load_tag( $key_offset ); |
203 | |
204 | if ( $trans_id ) { |
205 | if ( $bucket_tag->{is_new} ) { |
206 | # Must mark the HEAD as deleted because it doesn't exist |
207 | $self->_mark_as_deleted({ |
208 | tag => $key_tag, |
209 | trans_id => HEAD, |
210 | }); |
211 | } |
212 | } |
213 | else { |
214 | # If the HEAD isn't new, then we must take other transactions |
215 | # into account. If it is, then there can be no other transactions. |
216 | if ( !$bucket_tag->{is_new} ) { |
217 | my $old_value = $self->read_value( $trans_id, $base_offset, $key ); |
218 | if ( my @transactions = $self->_storage->current_transactions ) { |
219 | foreach my $other_trans_id ( @transactions ) { |
220 | next if $self->_has_keyloc_entry({ |
221 | tag => $key_tag, |
222 | trans_id => $other_trans_id, |
223 | }); |
224 | $self->write_value( $other_trans_id, $base_offset, $key, $old_value ); |
225 | } |
226 | } |
227 | } |
228 | } |
229 | |
40956c06 |
230 | my $value_loc = $self->_storage->request_space( |
231 | $self->_length_needed( $value, $key ), |
232 | ); |
233 | |
234 | $self->_add_key_offset({ |
235 | tag => $key_tag, |
236 | trans_id => $trans_id, |
237 | loc => $value_loc, |
fb451ba6 |
238 | }); |
239 | |
40956c06 |
240 | $self->_write_value( $value_loc, $key, $value, $key ); |
241 | |
fb451ba6 |
242 | return 1; |
243 | } |
244 | |
245 | sub _find_value_offset { |
246 | my $self = shift; |
247 | my ($args) = @_; |
248 | |
40956c06 |
249 | use Data::Dumper;warn Dumper $args; |
250 | |
fb451ba6 |
251 | my $key_tag = $self->load_tag( $args->{offset} ); |
252 | |
253 | my @head; |
254 | for ( my $i = 0; $i < $self->{max_buckets}; $i++ ) { |
255 | my ($loc, $trans_id, $is_deleted) = unpack( |
256 | "$self->{long_pack} C C", |
257 | substr( $key_tag->{content}, $i * $self->{key_size}, $self->{key_size} ), |
258 | ); |
259 | |
260 | if ( $trans_id == HEAD ) { |
261 | @head = ($loc, $is_deleted); |
262 | } |
263 | |
264 | next if $loc && $args->{trans_id} != $trans_id; |
265 | return( $loc, $is_deleted ); |
266 | } |
267 | |
268 | return @head if $args->{allow_head}; |
269 | return; |
270 | } |
271 | |
272 | #XXX Need to keep track of $bucket_tag->(ref_loc} and $bucket_tag->{ch} |
273 | sub _find_key_offset { |
274 | my $self = shift; |
275 | my ($args) = @_; |
276 | |
277 | my $bucket_tag = $self->load_tag( $args->{offset} ) |
278 | or $self->_throw_error( "INTERNAL ERROR - Cannot find tag" ); |
279 | |
fb451ba6 |
280 | #XXX What happens when $ch >= $self->{hash_size} ?? |
281 | for (my $ch = 0; $bucket_tag->{signature} ne SIG_BLIST; $ch++) { |
282 | my $num = ord substr($args->{key_md5}, $ch, 1); |
283 | |
284 | my $ref_loc = $bucket_tag->{offset} + ($num * $self->{long_size}); |
285 | $bucket_tag = $self->index_lookup( $bucket_tag, $num ); |
286 | |
287 | if (!$bucket_tag) { |
288 | return if !$args->{create}; |
289 | |
290 | my $loc = $self->_storage->request_space( |
291 | $self->tag_size( $self->{bucket_list_size} ), |
292 | ); |
293 | |
294 | $self->_storage->print_at( $ref_loc, pack($self->{long_pack}, $loc) ); |
295 | |
296 | $bucket_tag = $self->write_tag( |
297 | $loc, SIG_BLIST, |
298 | chr(0)x$self->{bucket_list_size}, |
299 | ); |
300 | |
301 | $bucket_tag->{ref_loc} = $ref_loc; |
302 | $bucket_tag->{ch} = $ch; |
303 | $bucket_tag->{is_new} = 1; |
304 | |
305 | last; |
306 | } |
307 | |
308 | $bucket_tag->{ch} = $ch; |
309 | $bucket_tag->{ref_loc} = $ref_loc; |
310 | } |
311 | |
312 | # Need to create a new keytag, too |
313 | if ( $bucket_tag->{is_new} ) { |
314 | my $keytag_loc = $self->_storage->request_space( |
315 | $self->tag_size( $self->{keyloc_size} ), |
316 | ); |
317 | |
318 | substr( $bucket_tag->{content}, 0, $self->{key_size} ) = |
319 | $args->{key_md5} . pack( "$self->{long_pack}", $keytag_loc ); |
320 | |
321 | $self->_storage->print_at( $bucket_tag->{offset}, $bucket_tag->{content} ); |
322 | |
323 | $self->write_tag( |
324 | $keytag_loc, SIG_KEYS, |
325 | chr(0)x$self->{keyloc_size}, |
326 | ); |
327 | |
328 | return( $keytag_loc, $bucket_tag ); |
329 | } |
330 | else { |
40956c06 |
331 | my ($key, $subloc, $index); |
fb451ba6 |
332 | BUCKET: |
333 | for ( my $i = 0; $i < $self->{max_buckets}; $i++ ) { |
40956c06 |
334 | ($key, $subloc) = $self->_get_key_subloc( |
fb451ba6 |
335 | $bucket_tag->{content}, $i, |
336 | ); |
337 | |
338 | next BUCKET if $subloc && $key ne $args->{key_md5}; |
40956c06 |
339 | |
340 | # Keep track of where we are, in case we need to create a new |
341 | # entry. |
342 | $index = $i; |
343 | last; |
fb451ba6 |
344 | } |
40956c06 |
345 | |
346 | # Either we have a subloc to return or we don't want to create a new |
347 | # entry. Either way, we need to return now. |
348 | return ($subloc, $bucket_tag) if $subloc || !$args->{create}; |
349 | |
350 | my $keytag_loc = $self->_storage->request_space( |
351 | $self->tag_size( $self->{keyloc_size} ), |
352 | ); |
353 | |
354 | # There's space left in this bucket |
355 | if ( defined $index ) { |
356 | substr( $bucket_tag->{content}, $index * $self->{key_size}, $self->{key_size} ) = |
357 | $args->{key_md5} . pack( "$self->{long_pack}", $keytag_loc ); |
358 | |
359 | $self->_storage->print_at( $bucket_tag->{offset}, $bucket_tag->{content} ); |
360 | } |
361 | # We need to split the index |
362 | else { |
363 | $self->split_index( $bucket_tag, $args->{key_md5}, $keytag_loc ); |
364 | } |
365 | |
366 | $self->write_tag( |
367 | $keytag_loc, SIG_KEYS, |
368 | chr(0)x$self->{keyloc_size}, |
369 | ); |
370 | |
371 | return( $keytag_loc, $bucket_tag ); |
fb451ba6 |
372 | } |
373 | |
374 | return; |
375 | } |
376 | |
377 | sub _read_value { |
378 | my $self = shift; |
379 | my ($args) = @_; |
380 | |
381 | return $self->read_from_loc( $args->{offset} ); |
382 | } |
383 | |
384 | sub _mark_as_deleted { |
385 | my $self = shift; |
386 | my ($args) = @_; |
387 | |
388 | my $is_changed; |
389 | for ( my $i = 0; $i < $self->{max_buckets}; $i++ ) { |
390 | my ($loc, $trans_id, $is_deleted) = unpack( |
391 | "$self->{long_pack} C C", |
392 | substr( $args->{tag}{content}, $i * $self->{key_size}, $self->{key_size} ), |
393 | ); |
394 | |
395 | |
396 | if ( $trans_id == $args->{trans_id} ) { |
397 | substr( $args->{tag}{content}, $i * $self->{key_size}, $self->{key_size} ) = pack( |
398 | "$self->{long_pack} C C", |
399 | $loc, $trans_id, 1, |
40956c06 |
400 | ); |
fb451ba6 |
401 | } |
402 | } |
403 | |
404 | if ( $is_changed ) { |
405 | $self->_storage->print_at( |
406 | $args->{tag}{offset}, $args->{tag}{content}, |
407 | ); |
408 | } |
409 | |
410 | return 1; |
411 | } |
412 | |
413 | sub _has_keyloc_entry { |
414 | my $self = shift; |
415 | my ($args) = @_; |
416 | |
417 | for ( my $i = 0; $i < $self->{max_buckets}; $i++ ) { |
418 | my ($loc, $trans_id, $is_deleted) = unpack( |
419 | "$self->{long_pack} C C", |
420 | substr( $args->{tag}{content}, $i * $self->{key_size}, $self->{key_size} ), |
421 | ); |
422 | |
423 | return 1 if $trans_id == $args->{trans_id}; |
424 | } |
425 | |
426 | return; |
427 | } |
428 | |
429 | sub _remove_key_offset { |
430 | my $self = shift; |
431 | my ($args) = @_; |
432 | |
433 | my $is_changed; |
434 | for ( my $i = 0; $i < $self->{max_buckets}; $i++ ) { |
435 | my ($loc, $trans_id, $is_deleted) = unpack( |
436 | "$self->{long_pack} C C", |
437 | substr( $args->{tag}{content}, $i * $self->{key_size}, $self->{key_size} ), |
438 | ); |
439 | |
440 | if ( $trans_id == $args->{trans_id} ) { |
441 | substr( $args->{tag}{content}, $i * $self->{key_size}, $self->{key_size} ) = ''; |
442 | $args->{tag}{content} .= chr(0) x $self->{key_size}; |
443 | $is_changed = 1; |
444 | redo; |
445 | } |
446 | } |
447 | |
448 | if ( $is_changed ) { |
449 | $self->_storage->print_at( |
450 | $args->{tag}{offset}, $args->{tag}{content}, |
451 | ); |
452 | } |
453 | |
454 | return 1; |
455 | } |
456 | |
40956c06 |
457 | sub _add_key_offset { |
fb451ba6 |
458 | my $self = shift; |
459 | my ($args) = @_; |
460 | |
40956c06 |
461 | my $is_changed; |
462 | for ( my $i = 0; $i < $self->{max_buckets}; $i++ ) { |
463 | my ($loc, $trans_id, $is_deleted) = unpack( |
464 | "$self->{long_pack} C C", |
465 | substr( $args->{tag}{content}, $i * $self->{key_size}, $self->{key_size} ), |
466 | ); |
fb451ba6 |
467 | |
40956c06 |
468 | if ( $trans_id == $args->{trans_id} || (!$loc && !$is_deleted) ) { |
469 | substr( $args->{tag}{content}, $i * $self->{key_size}, $self->{key_size} ) = pack( |
470 | "$self->{long_pack} C C", |
471 | $args->{loc}, $args->{trans_id}, 0, |
472 | ); |
473 | $is_changed = 1; |
474 | last; |
475 | } |
476 | } |
477 | |
478 | if ( $is_changed ) { |
479 | $self->_storage->print_at( |
480 | $args->{tag}{offset}, $args->{tag}{content}, |
481 | ); |
482 | } |
483 | else { |
484 | die "Why didn't _add_key_offset() change something?!\n"; |
485 | } |
486 | |
487 | return 1; |
fb451ba6 |
488 | } |
489 | |
490 | sub setup_fh { |
491 | my $self = shift; |
492 | my ($obj) = @_; |
493 | |
494 | # Need to remove use of $fh here |
495 | my $fh = $self->_storage->{fh}; |
496 | flock $fh, LOCK_EX; |
497 | |
498 | #XXX The duplication of calculate_sizes needs to go away |
499 | unless ( $obj->{base_offset} ) { |
500 | my $bytes_read = $self->read_file_header; |
501 | |
502 | $self->calculate_sizes; |
503 | |
504 | ## |
505 | # File is empty -- write header and master index |
506 | ## |
507 | if (!$bytes_read) { |
508 | $self->_storage->audit( "# Database created on" ); |
509 | |
510 | $self->write_file_header; |
511 | |
512 | $obj->{base_offset} = $self->_storage->request_space( |
513 | $self->tag_size( $self->{keyloc_size} ), |
514 | ); |
515 | |
516 | my $value_spot = $self->_storage->request_space( |
517 | $self->tag_size( $self->{index_size} ), |
518 | ); |
519 | |
520 | $self->write_tag( |
521 | $obj->{base_offset}, SIG_KEYS, |
522 | pack( "$self->{long_pack} C C", $obj->{base_offset}, 0, 0 ), |
523 | chr(0) x ($self->{index_size} - $self->{long_size} + 2), |
524 | ); |
525 | |
526 | $self->write_tag( |
527 | $value_spot, $obj->_type, |
528 | chr(0)x$self->{index_size}, |
529 | ); |
530 | |
531 | # Flush the filehandle |
532 | my $old_fh = select $fh; |
533 | my $old_af = $|; $| = 1; $| = $old_af; |
534 | select $old_fh; |
535 | } |
536 | else { |
537 | $obj->{base_offset} = $bytes_read; |
538 | |
539 | ## |
540 | # Get our type from master index header |
541 | ## |
542 | my $tag = $self->load_tag($obj->_base_offset); |
543 | unless ( $tag ) { |
544 | flock $fh, LOCK_UN; |
545 | $self->_throw_error("Corrupted file, no master index record"); |
546 | } |
547 | |
548 | unless ($obj->_type eq $tag->{signature}) { |
549 | flock $fh, LOCK_UN; |
550 | $self->_throw_error("File type mismatch"); |
551 | } |
552 | } |
553 | } |
554 | else { |
555 | $self->calculate_sizes; |
556 | } |
557 | |
558 | #XXX We have to make sure we don't mess up when autoflush isn't turned on |
559 | $self->_storage->set_inode; |
560 | |
561 | flock $fh, LOCK_UN; |
562 | |
563 | return 1; |
564 | } |
565 | |
566 | 1; |
567 | __END__ |