Commit | Line | Data |
a20d9a3f |
1 | package DBM::Deep::Engine; |
2 | |
3 | use strict; |
4 | |
5 | use Fcntl qw( :DEFAULT :flock :seek ); |
6 | |
612969fb |
7 | sub precalc_sizes { |
beac1dff |
8 | ## |
9 | # Precalculate index, bucket and bucket list sizes |
10 | ## |
251dfd0e |
11 | my $self = shift; |
1bf65be7 |
12 | |
251dfd0e |
13 | $self->{index_size} = (2**8) * $self->{long_size}; |
14 | $self->{bucket_size} = $self->{hash_size} + $self->{long_size}; |
15 | $self->{bucket_list_size} = $self->{max_buckets} * $self->{bucket_size}; |
1bf65be7 |
16 | |
251dfd0e |
17 | return 1; |
1bf65be7 |
18 | } |
19 | |
20 | sub set_pack { |
beac1dff |
21 | ## |
22 | # Set pack/unpack modes (see file header for more) |
23 | ## |
251dfd0e |
24 | my $self = shift; |
1bf65be7 |
25 | my ($long_s, $long_p, $data_s, $data_p) = @_; |
26 | |
81d16922 |
27 | ## |
28 | # Set to 4 and 'N' for 32-bit offset tags (default). Theoretical limit of 4 GB per file. |
beac1dff |
29 | # (Perl must be compiled with largefile support for files > 2 GB) |
81d16922 |
30 | # |
31 | # Set to 8 and 'Q' for 64-bit offsets. Theoretical limit of 16 XB per file. |
beac1dff |
32 | # (Perl must be compiled with largefile and 64-bit long support) |
81d16922 |
33 | ## |
251dfd0e |
34 | $self->{long_size} = $long_s ? $long_s : 4; |
35 | $self->{long_pack} = $long_p ? $long_p : 'N'; |
1bf65be7 |
36 | |
81d16922 |
37 | ## |
38 | # Set to 4 and 'N' for 32-bit data length prefixes. Limit of 4 GB for each key/value. |
39 | # Upgrading this is possible (see above) but probably not necessary. If you need |
40 | # more than 4 GB for a single key or value, this module is really not for you :-) |
41 | ## |
251dfd0e |
42 | $self->{data_size} = $data_s ? $data_s : 4; |
43 | $self->{data_pack} = $data_p ? $data_p : 'N'; |
1bf65be7 |
44 | |
beac1dff |
45 | return $self->precalc_sizes(); |
1bf65be7 |
46 | } |
47 | |
48 | sub set_digest { |
beac1dff |
49 | ## |
50 | # Set key digest function (default is MD5) |
51 | ## |
251dfd0e |
52 | my $self = shift; |
1bf65be7 |
53 | my ($digest_func, $hash_size) = @_; |
54 | |
d0b74c17 |
55 | $self->{digest} = $digest_func ? $digest_func : \&Digest::MD5::md5; |
251dfd0e |
56 | $self->{hash_size} = $hash_size ? $hash_size : 16; |
612969fb |
57 | |
beac1dff |
58 | return $self->precalc_sizes(); |
612969fb |
59 | } |
60 | |
61 | sub new { |
62 | my $class = shift; |
63 | my ($args) = @_; |
64 | |
65 | my $self = bless { |
66 | long_size => 4, |
67 | long_pack => 'N', |
68 | data_size => 4, |
69 | data_pack => 'N', |
251dfd0e |
70 | |
612969fb |
71 | digest => \&Digest::MD5::md5, |
72 | hash_size => 16, |
251dfd0e |
73 | |
81d16922 |
74 | ## |
75 | # Maximum number of buckets per list before another level of indexing is done. |
76 | # Increase this value for slightly greater speed, but larger database files. |
77 | # DO NOT decrease this value below 16, due to risk of recursive reindex overrun. |
78 | ## |
612969fb |
79 | max_buckets => 16, |
80 | }, $class; |
81 | |
251dfd0e |
82 | $self->precalc_sizes; |
612969fb |
83 | |
84 | return $self; |
1bf65be7 |
85 | } |
86 | |
70b55428 |
87 | sub setup_fh { |
88 | my $self = shift; |
89 | my ($obj) = @_; |
90 | |
91 | $self->open( $obj ) if !defined $obj->_fh; |
92 | |
93 | #XXX Is {end} busted? Can't we just seek( $fh, 0, SEEK_END ) ? |
94 | unless ( $obj->_root->{inode} ) { |
95 | my @stats = stat($obj->_fh); |
96 | $obj->_root->{inode} = $stats[1]; |
97 | $obj->_root->{end} = $stats[7]; |
98 | } |
99 | |
100 | return 1; |
101 | } |
102 | |
a20d9a3f |
103 | sub open { |
20f7b20c |
104 | ## |
105 | # Open a fh to the database, create if nonexistent. |
106 | # Make sure file signature matches DBM::Deep spec. |
107 | ## |
a20d9a3f |
108 | my $self = shift; |
70b55428 |
109 | my ($obj) = @_; |
a20d9a3f |
110 | |
3d1b8be9 |
111 | if (defined($obj->_fh)) { $self->close_fh( $obj ); } |
20f7b20c |
112 | |
a20d9a3f |
113 | eval { |
114 | local $SIG{'__DIE__'}; |
115 | # Theoretically, adding O_BINARY should remove the need for the binmode |
116 | # Of course, testing it is going to be ... interesting. |
117 | my $flags = O_RDWR | O_CREAT | O_BINARY; |
118 | |
119 | my $fh; |
cd59cad8 |
120 | sysopen( $fh, $obj->_root->{file}, $flags ) |
a20d9a3f |
121 | or $fh = undef; |
cd59cad8 |
122 | $obj->_root->{fh} = $fh; |
123 | }; if ($@ ) { $obj->_throw_error( "Received error: $@\n" ); } |
20f7b20c |
124 | if (! defined($obj->_fh)) { |
125 | return $obj->_throw_error("Cannot sysopen file: " . $obj->_root->{file} . ": $!"); |
126 | } |
a20d9a3f |
127 | |
cd59cad8 |
128 | my $fh = $obj->_fh; |
a20d9a3f |
129 | |
130 | #XXX Can we remove this by using the right sysopen() flags? |
131 | # Maybe ... q.v. above |
132 | binmode $fh; # for win32 |
133 | |
cd59cad8 |
134 | if ($obj->_root->{autoflush}) { |
a20d9a3f |
135 | my $old = select $fh; |
136 | $|=1; |
137 | select $old; |
138 | } |
20f7b20c |
139 | |
cd59cad8 |
140 | seek($fh, 0 + $obj->_root->{file_offset}, SEEK_SET); |
a20d9a3f |
141 | |
142 | my $signature; |
143 | my $bytes_read = read( $fh, $signature, length(DBM::Deep->SIG_FILE)); |
20f7b20c |
144 | |
a20d9a3f |
145 | ## |
146 | # File is empty -- write signature and master index |
147 | ## |
148 | if (!$bytes_read) { |
cd59cad8 |
149 | seek($fh, 0 + $obj->_root->{file_offset}, SEEK_SET); |
a20d9a3f |
150 | print( $fh DBM::Deep->SIG_FILE); |
d0b74c17 |
151 | |
ec1bce6b |
152 | $self->create_tag($obj, $obj->_base_offset, $obj->_type, chr(0) x $self->{index_size}); |
a20d9a3f |
153 | |
154 | my $plain_key = "[base]"; |
251dfd0e |
155 | print( $fh pack($self->{data_pack}, length($plain_key)) . $plain_key ); |
a20d9a3f |
156 | |
157 | # Flush the filehandle |
158 | my $old_fh = select $fh; |
159 | my $old_af = $|; $| = 1; $| = $old_af; |
160 | select $old_fh; |
161 | |
a20d9a3f |
162 | return 1; |
163 | } |
20f7b20c |
164 | |
a20d9a3f |
165 | ## |
166 | # Check signature was valid |
167 | ## |
168 | unless ($signature eq DBM::Deep->SIG_FILE) { |
3d1b8be9 |
169 | $self->close_fh( $obj ); |
cd59cad8 |
170 | return $obj->_throw_error("Signature not found -- file is not a Deep DB"); |
a20d9a3f |
171 | } |
172 | |
a20d9a3f |
173 | ## |
174 | # Get our type from master index signature |
175 | ## |
d4b1166e |
176 | my $tag = $self->load_tag($obj, $obj->_base_offset); |
a20d9a3f |
177 | if (!$tag) { |
20f7b20c |
178 | return $obj->_throw_error("Corrupted file, no master index record"); |
a20d9a3f |
179 | } |
d0b74c17 |
180 | |
cd59cad8 |
181 | if ($obj->{type} ne $tag->{signature}) { |
20f7b20c |
182 | return $obj->_throw_error("File type mismatch"); |
a20d9a3f |
183 | } |
20f7b20c |
184 | |
d0b74c17 |
185 | #XXX We probably also want to store the hash algorithm name and not assume anything |
186 | #XXX The cool thing would be to allow a different hashing algorithm at every level |
187 | |
a20d9a3f |
188 | return 1; |
189 | } |
190 | |
3d1b8be9 |
191 | sub close_fh { |
cd59cad8 |
192 | my $self = shift; |
a21f2d90 |
193 | my ($obj) = @_; |
cd59cad8 |
194 | |
195 | if ( my $fh = $obj->_root->{fh} ) { |
196 | close $fh; |
197 | } |
198 | $obj->_root->{fh} = undef; |
199 | |
200 | return 1; |
201 | } |
202 | |
d4b1166e |
203 | sub create_tag { |
20f7b20c |
204 | ## |
205 | # Given offset, signature and content, create tag and write to disk |
206 | ## |
d4b1166e |
207 | my $self = shift; |
20f7b20c |
208 | my ($obj, $offset, $sig, $content) = @_; |
209 | my $size = length($content); |
210 | |
d4b1166e |
211 | my $fh = $obj->_fh; |
212 | |
20f7b20c |
213 | seek($fh, $offset + $obj->_root->{file_offset}, SEEK_SET); |
251dfd0e |
214 | print( $fh $sig . pack($self->{data_pack}, $size) . $content ); |
20f7b20c |
215 | |
216 | if ($offset == $obj->_root->{end}) { |
251dfd0e |
217 | $obj->_root->{end} += DBM::Deep->SIG_SIZE + $self->{data_size} + $size; |
20f7b20c |
218 | } |
219 | |
220 | return { |
221 | signature => $sig, |
222 | size => $size, |
251dfd0e |
223 | offset => $offset + DBM::Deep->SIG_SIZE + $self->{data_size}, |
20f7b20c |
224 | content => $content |
225 | }; |
d4b1166e |
226 | } |
227 | |
228 | sub load_tag { |
20f7b20c |
229 | ## |
230 | # Given offset, load single tag and return signature, size and data |
231 | ## |
d4b1166e |
232 | my $self = shift; |
20f7b20c |
233 | my ($obj, $offset) = @_; |
234 | |
d4b1166e |
235 | my $fh = $obj->_fh; |
236 | |
20f7b20c |
237 | seek($fh, $offset + $obj->_root->{file_offset}, SEEK_SET); |
238 | if (eof $fh) { return undef; } |
239 | |
d4b1166e |
240 | my $b; |
251dfd0e |
241 | read( $fh, $b, DBM::Deep->SIG_SIZE + $self->{data_size} ); |
242 | my ($sig, $size) = unpack( "A $self->{data_pack}", $b ); |
20f7b20c |
243 | |
244 | my $buffer; |
245 | read( $fh, $buffer, $size); |
246 | |
247 | return { |
248 | signature => $sig, |
249 | size => $size, |
251dfd0e |
250 | offset => $offset + DBM::Deep->SIG_SIZE + $self->{data_size}, |
20f7b20c |
251 | content => $buffer |
252 | }; |
d4b1166e |
253 | } |
254 | |
20f7b20c |
255 | sub add_bucket { |
256 | ## |
257 | # Adds one key/value pair to bucket list, given offset, MD5 digest of key, |
258 | # plain (undigested) key and value. |
259 | ## |
d4b1166e |
260 | my $self = shift; |
20f7b20c |
261 | my ($obj, $tag, $md5, $plain_key, $value) = @_; |
262 | my $keys = $tag->{content}; |
263 | my $location = 0; |
264 | my $result = 2; |
265 | |
266 | my $root = $obj->_root; |
267 | |
268 | my $is_dbm_deep = eval { local $SIG{'__DIE__'}; $value->isa( 'DBM::Deep' ) }; |
269 | my $internal_ref = $is_dbm_deep && ($value->_root eq $root); |
270 | |
271 | my $fh = $obj->_fh; |
272 | |
273 | ## |
274 | # Iterate through buckets, seeing if this is a new entry or a replace. |
275 | ## |
d0b74c17 |
276 | for (my $i = 0; $i < $self->{max_buckets}; $i++) { |
251dfd0e |
277 | my $subloc = unpack($self->{long_pack}, substr($keys, ($i * $self->{bucket_size}) + $self->{hash_size}, $self->{long_size})); |
20f7b20c |
278 | if (!$subloc) { |
279 | ## |
280 | # Found empty bucket (end of list). Populate and exit loop. |
281 | ## |
282 | $result = 2; |
283 | |
284 | $location = $internal_ref |
285 | ? $value->_base_offset |
286 | : $root->{end}; |
287 | |
251dfd0e |
288 | seek($fh, $tag->{offset} + ($i * $self->{bucket_size}) + $root->{file_offset}, SEEK_SET); |
289 | print( $fh $md5 . pack($self->{long_pack}, $location) ); |
20f7b20c |
290 | last; |
291 | } |
292 | |
251dfd0e |
293 | my $key = substr($keys, $i * $self->{bucket_size}, $self->{hash_size}); |
20f7b20c |
294 | if ($md5 eq $key) { |
295 | ## |
296 | # Found existing bucket with same key. Replace with new value. |
297 | ## |
298 | $result = 1; |
299 | |
300 | if ($internal_ref) { |
301 | $location = $value->_base_offset; |
251dfd0e |
302 | seek($fh, $tag->{offset} + ($i * $self->{bucket_size}) + $root->{file_offset}, SEEK_SET); |
303 | print( $fh $md5 . pack($self->{long_pack}, $location) ); |
20f7b20c |
304 | return $result; |
305 | } |
306 | |
307 | seek($fh, $subloc + DBM::Deep->SIG_SIZE + $root->{file_offset}, SEEK_SET); |
308 | my $size; |
251dfd0e |
309 | read( $fh, $size, $self->{data_size}); $size = unpack($self->{data_pack}, $size); |
20f7b20c |
310 | |
311 | ## |
312 | # If value is a hash, array, or raw value with equal or less size, we can |
313 | # reuse the same content area of the database. Otherwise, we have to create |
314 | # a new content area at the EOF. |
315 | ## |
316 | my $actual_length; |
317 | my $r = Scalar::Util::reftype( $value ) || ''; |
318 | if ( $r eq 'HASH' || $r eq 'ARRAY' ) { |
ec1bce6b |
319 | $actual_length = $self->{index_size}; |
20f7b20c |
320 | |
321 | # if autobless is enabled, must also take into consideration |
322 | # the class name, as it is stored along with key/value. |
323 | if ( $root->{autobless} ) { |
324 | my $value_class = Scalar::Util::blessed($value); |
325 | if ( defined $value_class && !$value->isa('DBM::Deep') ) { |
326 | $actual_length += length($value_class); |
327 | } |
328 | } |
329 | } |
330 | else { $actual_length = length($value); } |
331 | |
332 | if ($actual_length <= $size) { |
333 | $location = $subloc; |
334 | } |
335 | else { |
336 | $location = $root->{end}; |
251dfd0e |
337 | seek($fh, $tag->{offset} + ($i * $self->{bucket_size}) + $self->{hash_size} + $root->{file_offset}, SEEK_SET); |
338 | print( $fh pack($self->{long_pack}, $location) ); |
20f7b20c |
339 | } |
340 | |
341 | last; |
342 | } |
343 | } |
344 | |
345 | ## |
346 | # If this is an internal reference, return now. |
347 | # No need to write value or plain key |
348 | ## |
349 | if ($internal_ref) { |
350 | return $result; |
351 | } |
352 | |
353 | ## |
354 | # If bucket didn't fit into list, split into a new index level |
355 | ## |
356 | if (!$location) { |
357 | seek($fh, $tag->{ref_loc} + $root->{file_offset}, SEEK_SET); |
251dfd0e |
358 | print( $fh pack($self->{long_pack}, $root->{end}) ); |
20f7b20c |
359 | |
ec1bce6b |
360 | my $index_tag = $self->create_tag($obj, $root->{end}, DBM::Deep->SIG_INDEX, chr(0) x $self->{index_size}); |
20f7b20c |
361 | my @offsets = (); |
362 | |
251dfd0e |
363 | $keys .= $md5 . pack($self->{long_pack}, 0); |
20f7b20c |
364 | |
251dfd0e |
365 | for (my $i=0; $i<=$self->{max_buckets}; $i++) { |
366 | my $key = substr($keys, $i * $self->{bucket_size}, $self->{hash_size}); |
20f7b20c |
367 | if ($key) { |
251dfd0e |
368 | my $old_subloc = unpack($self->{long_pack}, substr($keys, ($i * $self->{bucket_size}) + |
369 | $self->{hash_size}, $self->{long_size})); |
20f7b20c |
370 | my $num = ord(substr($key, $tag->{ch} + 1, 1)); |
371 | |
372 | if ($offsets[$num]) { |
251dfd0e |
373 | my $offset = $offsets[$num] + DBM::Deep->SIG_SIZE + $self->{data_size}; |
20f7b20c |
374 | seek($fh, $offset + $root->{file_offset}, SEEK_SET); |
375 | my $subkeys; |
251dfd0e |
376 | read( $fh, $subkeys, $self->{bucket_list_size}); |
20f7b20c |
377 | |
251dfd0e |
378 | for (my $k=0; $k<$self->{max_buckets}; $k++) { |
379 | my $subloc = unpack($self->{long_pack}, substr($subkeys, ($k * $self->{bucket_size}) + |
380 | $self->{hash_size}, $self->{long_size})); |
20f7b20c |
381 | if (!$subloc) { |
251dfd0e |
382 | seek($fh, $offset + ($k * $self->{bucket_size}) + $root->{file_offset}, SEEK_SET); |
383 | print( $fh $key . pack($self->{long_pack}, $old_subloc || $root->{end}) ); |
20f7b20c |
384 | last; |
385 | } |
386 | } # k loop |
387 | } |
388 | else { |
389 | $offsets[$num] = $root->{end}; |
251dfd0e |
390 | seek($fh, $index_tag->{offset} + ($num * $self->{long_size}) + $root->{file_offset}, SEEK_SET); |
391 | print( $fh pack($self->{long_pack}, $root->{end}) ); |
20f7b20c |
392 | |
251dfd0e |
393 | my $blist_tag = $self->create_tag($obj, $root->{end}, DBM::Deep->SIG_BLIST, chr(0) x $self->{bucket_list_size}); |
20f7b20c |
394 | |
395 | seek($fh, $blist_tag->{offset} + $root->{file_offset}, SEEK_SET); |
251dfd0e |
396 | print( $fh $key . pack($self->{long_pack}, $old_subloc || $root->{end}) ); |
20f7b20c |
397 | } |
398 | } # key is real |
399 | } # i loop |
400 | |
401 | $location ||= $root->{end}; |
402 | } # re-index bucket list |
403 | |
404 | ## |
405 | # Seek to content area and store signature, value and plaintext key |
406 | ## |
407 | if ($location) { |
408 | my $content_length; |
409 | seek($fh, $location + $root->{file_offset}, SEEK_SET); |
410 | |
411 | ## |
412 | # Write signature based on content type, set content length and write actual value. |
413 | ## |
414 | my $r = Scalar::Util::reftype($value) || ''; |
415 | if ($r eq 'HASH') { |
416 | print( $fh DBM::Deep->TYPE_HASH ); |
251dfd0e |
417 | print( $fh pack($self->{data_pack}, $self->{index_size}) . chr(0) x $self->{index_size} ); |
ec1bce6b |
418 | $content_length = $self->{index_size}; |
20f7b20c |
419 | } |
420 | elsif ($r eq 'ARRAY') { |
421 | print( $fh DBM::Deep->TYPE_ARRAY ); |
251dfd0e |
422 | print( $fh pack($self->{data_pack}, $self->{index_size}) . chr(0) x $self->{index_size} ); |
ec1bce6b |
423 | $content_length = $self->{index_size}; |
20f7b20c |
424 | } |
425 | elsif (!defined($value)) { |
426 | print( $fh DBM::Deep->SIG_NULL ); |
251dfd0e |
427 | print( $fh pack($self->{data_pack}, 0) ); |
20f7b20c |
428 | $content_length = 0; |
429 | } |
430 | else { |
431 | print( $fh DBM::Deep->SIG_DATA ); |
251dfd0e |
432 | print( $fh pack($self->{data_pack}, length($value)) . $value ); |
20f7b20c |
433 | $content_length = length($value); |
434 | } |
435 | |
436 | ## |
437 | # Plain key is stored AFTER value, as keys are typically fetched less often. |
438 | ## |
251dfd0e |
439 | print( $fh pack($self->{data_pack}, length($plain_key)) . $plain_key ); |
20f7b20c |
440 | |
441 | ## |
442 | # If value is blessed, preserve class name |
443 | ## |
444 | if ( $root->{autobless} ) { |
445 | my $value_class = Scalar::Util::blessed($value); |
446 | if ( defined $value_class && $value_class ne 'DBM::Deep' ) { |
447 | ## |
448 | # Blessed ref -- will restore later |
449 | ## |
450 | print( $fh chr(1) ); |
251dfd0e |
451 | print( $fh pack($self->{data_pack}, length($value_class)) . $value_class ); |
20f7b20c |
452 | $content_length += 1; |
251dfd0e |
453 | $content_length += $self->{data_size} + length($value_class); |
20f7b20c |
454 | } |
455 | else { |
456 | print( $fh chr(0) ); |
457 | $content_length += 1; |
458 | } |
459 | } |
460 | |
461 | ## |
462 | # If this is a new content area, advance EOF counter |
463 | ## |
464 | if ($location == $root->{end}) { |
465 | $root->{end} += DBM::Deep->SIG_SIZE; |
251dfd0e |
466 | $root->{end} += $self->{data_size} + $content_length; |
467 | $root->{end} += $self->{data_size} + length($plain_key); |
20f7b20c |
468 | } |
469 | |
470 | ## |
471 | # If content is a hash or array, create new child DBM::Deep object and |
472 | # pass each key or element to it. |
473 | ## |
474 | if ($r eq 'HASH') { |
475 | my $branch = DBM::Deep->new( |
476 | type => DBM::Deep->TYPE_HASH, |
477 | base_offset => $location, |
478 | root => $root, |
479 | ); |
480 | foreach my $key (keys %{$value}) { |
481 | $branch->STORE( $key, $value->{$key} ); |
482 | } |
483 | } |
484 | elsif ($r eq 'ARRAY') { |
485 | my $branch = DBM::Deep->new( |
486 | type => DBM::Deep->TYPE_ARRAY, |
487 | base_offset => $location, |
488 | root => $root, |
489 | ); |
490 | my $index = 0; |
491 | foreach my $element (@{$value}) { |
492 | $branch->STORE( $index, $element ); |
493 | $index++; |
494 | } |
495 | } |
496 | |
497 | return $result; |
498 | } |
d4b1166e |
499 | |
20f7b20c |
500 | return $obj->_throw_error("Fatal error: indexing failed -- possibly due to corruption in file"); |
d4b1166e |
501 | } |
502 | |
9020ee8c |
503 | sub get_bucket_value { |
beac1dff |
504 | ## |
505 | # Fetch single value given tag and MD5 digested key. |
506 | ## |
507 | my $self = shift; |
508 | my ($obj, $tag, $md5) = @_; |
509 | my $keys = $tag->{content}; |
9020ee8c |
510 | |
511 | my $fh = $obj->_fh; |
512 | |
beac1dff |
513 | ## |
514 | # Iterate through buckets, looking for a key match |
515 | ## |
9020ee8c |
516 | BUCKET: |
beac1dff |
517 | for (my $i=0; $i<$self->{max_buckets}; $i++) { |
518 | my $key = substr($keys, $i * $self->{bucket_size}, $self->{hash_size}); |
519 | my $subloc = unpack($self->{long_pack}, substr($keys, ($i * $self->{bucket_size}) + $self->{hash_size}, $self->{long_size})); |
9020ee8c |
520 | |
beac1dff |
521 | if (!$subloc) { |
522 | ## |
523 | # Hit end of list, no match |
524 | ## |
525 | return; |
526 | } |
9020ee8c |
527 | |
528 | if ( $md5 ne $key ) { |
529 | next BUCKET; |
530 | } |
531 | |
532 | ## |
533 | # Found match -- seek to offset and read signature |
534 | ## |
535 | my $signature; |
536 | seek($fh, $subloc + $obj->_root->{file_offset}, SEEK_SET); |
537 | read( $fh, $signature, DBM::Deep->SIG_SIZE); |
d0b74c17 |
538 | |
9020ee8c |
539 | ## |
540 | # If value is a hash or array, return new DBM::Deep object with correct offset |
541 | ## |
542 | if (($signature eq DBM::Deep->TYPE_HASH) || ($signature eq DBM::Deep->TYPE_ARRAY)) { |
543 | my $obj = DBM::Deep->new( |
544 | type => $signature, |
545 | base_offset => $subloc, |
546 | root => $obj->_root, |
547 | ); |
d0b74c17 |
548 | |
9020ee8c |
549 | if ($obj->_root->{autobless}) { |
550 | ## |
551 | # Skip over value and plain key to see if object needs |
552 | # to be re-blessed |
553 | ## |
251dfd0e |
554 | seek($fh, $self->{data_size} + $self->{index_size}, SEEK_CUR); |
d0b74c17 |
555 | |
9020ee8c |
556 | my $size; |
251dfd0e |
557 | read( $fh, $size, $self->{data_size}); $size = unpack($self->{data_pack}, $size); |
9020ee8c |
558 | if ($size) { seek($fh, $size, SEEK_CUR); } |
d0b74c17 |
559 | |
9020ee8c |
560 | my $bless_bit; |
561 | read( $fh, $bless_bit, 1); |
562 | if (ord($bless_bit)) { |
563 | ## |
564 | # Yes, object needs to be re-blessed |
565 | ## |
566 | my $class_name; |
251dfd0e |
567 | read( $fh, $size, $self->{data_size}); $size = unpack($self->{data_pack}, $size); |
9020ee8c |
568 | if ($size) { read( $fh, $class_name, $size); } |
569 | if ($class_name) { $obj = bless( $obj, $class_name ); } |
570 | } |
571 | } |
d0b74c17 |
572 | |
9020ee8c |
573 | return $obj; |
574 | } |
d0b74c17 |
575 | |
9020ee8c |
576 | ## |
577 | # Otherwise return actual value |
578 | ## |
579 | elsif ($signature eq DBM::Deep->SIG_DATA) { |
580 | my $size; |
581 | my $value = ''; |
251dfd0e |
582 | read( $fh, $size, $self->{data_size}); $size = unpack($self->{data_pack}, $size); |
9020ee8c |
583 | if ($size) { read( $fh, $value, $size); } |
584 | return $value; |
585 | } |
d0b74c17 |
586 | |
9020ee8c |
587 | ## |
588 | # Key exists, but content is null |
589 | ## |
590 | else { return; } |
beac1dff |
591 | } # i loop |
9020ee8c |
592 | |
beac1dff |
593 | return; |
9020ee8c |
594 | } |
ab0e4957 |
595 | |
596 | sub delete_bucket { |
beac1dff |
597 | ## |
598 | # Delete single key/value pair given tag and MD5 digested key. |
599 | ## |
600 | my $self = shift; |
601 | my ($obj, $tag, $md5) = @_; |
602 | my $keys = $tag->{content}; |
ab0e4957 |
603 | |
604 | my $fh = $obj->_fh; |
d0b74c17 |
605 | |
beac1dff |
606 | ## |
607 | # Iterate through buckets, looking for a key match |
608 | ## |
ab0e4957 |
609 | BUCKET: |
beac1dff |
610 | for (my $i=0; $i<$self->{max_buckets}; $i++) { |
611 | my $key = substr($keys, $i * $self->{bucket_size}, $self->{hash_size}); |
612 | my $subloc = unpack($self->{long_pack}, substr($keys, ($i * $self->{bucket_size}) + $self->{hash_size}, $self->{long_size})); |
ab0e4957 |
613 | |
beac1dff |
614 | if (!$subloc) { |
615 | ## |
616 | # Hit end of list, no match |
617 | ## |
618 | return; |
619 | } |
ab0e4957 |
620 | |
621 | if ( $md5 ne $key ) { |
622 | next BUCKET; |
623 | } |
624 | |
625 | ## |
626 | # Matched key -- delete bucket and return |
627 | ## |
251dfd0e |
628 | seek($fh, $tag->{offset} + ($i * $self->{bucket_size}) + $obj->_root->{file_offset}, SEEK_SET); |
629 | print( $fh substr($keys, ($i+1) * $self->{bucket_size} ) ); |
630 | print( $fh chr(0) x $self->{bucket_size} ); |
d0b74c17 |
631 | |
ab0e4957 |
632 | return 1; |
beac1dff |
633 | } # i loop |
ab0e4957 |
634 | |
beac1dff |
635 | return; |
ab0e4957 |
636 | } |
637 | |
912d50b1 |
638 | sub bucket_exists { |
beac1dff |
639 | ## |
640 | # Check existence of single key given tag and MD5 digested key. |
641 | ## |
642 | my $self = shift; |
643 | my ($obj, $tag, $md5) = @_; |
644 | my $keys = $tag->{content}; |
d0b74c17 |
645 | |
beac1dff |
646 | ## |
647 | # Iterate through buckets, looking for a key match |
648 | ## |
912d50b1 |
649 | BUCKET: |
beac1dff |
650 | for (my $i=0; $i<$self->{max_buckets}; $i++) { |
651 | my $key = substr($keys, $i * $self->{bucket_size}, $self->{hash_size}); |
652 | my $subloc = unpack($self->{long_pack}, substr($keys, ($i * $self->{bucket_size}) + $self->{hash_size}, $self->{long_size})); |
912d50b1 |
653 | |
beac1dff |
654 | if (!$subloc) { |
655 | ## |
656 | # Hit end of list, no match |
657 | ## |
658 | return; |
659 | } |
912d50b1 |
660 | |
661 | if ( $md5 ne $key ) { |
662 | next BUCKET; |
663 | } |
664 | |
665 | ## |
666 | # Matched key -- return true |
667 | ## |
668 | return 1; |
beac1dff |
669 | } # i loop |
912d50b1 |
670 | |
beac1dff |
671 | return; |
912d50b1 |
672 | } |
673 | |
6736c116 |
674 | sub find_bucket_list { |
beac1dff |
675 | ## |
676 | # Locate offset for bucket list, given digested key |
677 | ## |
678 | my $self = shift; |
d0b74c17 |
679 | my ($obj, $md5, $args) = @_; |
680 | $args = {} unless $args; |
681 | |
beac1dff |
682 | ## |
683 | # Locate offset for bucket list using digest index system |
684 | ## |
685 | my $ch = 0; |
686 | my $tag = $self->load_tag($obj, $obj->_base_offset); |
d0b74c17 |
687 | if (!$tag) { |
688 | return $self->_throw_error( "INTERNAL ERROR - Cannot find tag" ); |
689 | } |
690 | |
beac1dff |
691 | while ($tag->{signature} ne DBM::Deep->SIG_BLIST) { |
d0b74c17 |
692 | my $num = ord substr($md5, $ch, 1); |
693 | |
694 | my $ref_loc = $tag->{offset} + ($num * $self->{long_size}); |
695 | $tag = $self->index_lookup( $obj, $tag, $num ); |
696 | |
697 | if (!$tag) { |
698 | if ( $args->{create} ) { |
699 | my $fh = $obj->_fh; |
700 | seek($fh, $ref_loc + $obj->_root->{file_offset}, SEEK_SET); |
701 | print( $fh pack($self->{long_pack}, $obj->_root->{end}) ); |
702 | |
703 | $tag = $self->create_tag( |
704 | $obj, $obj->_root->{end}, |
705 | DBM::Deep->SIG_BLIST, |
706 | chr(0) x $self->{bucket_list_size}, |
707 | ); |
708 | |
709 | $tag->{ref_loc} = $ref_loc; |
710 | $tag->{ch} = $ch; |
711 | |
712 | last; |
713 | } |
714 | else { |
715 | return; |
716 | } |
717 | } |
718 | |
719 | $tag->{ch} = $ch; |
720 | $tag->{ref_loc} = $ref_loc; |
721 | |
beac1dff |
722 | $ch++; |
723 | } |
d0b74c17 |
724 | |
beac1dff |
725 | return $tag; |
6736c116 |
726 | } |
727 | |
d0b74c17 |
728 | sub index_lookup { |
729 | ## |
730 | # Given index tag, lookup single entry in index and return . |
731 | ## |
732 | my $self = shift; |
733 | my ($obj, $tag, $index) = @_; |
734 | |
735 | my $location = unpack( |
736 | $self->{long_pack}, |
737 | substr( |
738 | $tag->{content}, |
739 | $index * $self->{long_size}, |
740 | $self->{long_size}, |
741 | ), |
742 | ); |
743 | |
744 | if (!$location) { return; } |
745 | |
746 | return $self->load_tag( $obj, $location ); |
747 | } |
748 | |
6736c116 |
749 | sub traverse_index { |
beac1dff |
750 | ## |
751 | # Scan index and recursively step into deeper levels, looking for next key. |
752 | ## |
6736c116 |
753 | my $self = shift; |
754 | my ($obj, $offset, $ch, $force_return_next) = @_; |
755 | $force_return_next = undef unless $force_return_next; |
d0b74c17 |
756 | |
beac1dff |
757 | my $tag = $self->load_tag($obj, $offset ); |
6736c116 |
758 | |
759 | my $fh = $obj->_fh; |
d0b74c17 |
760 | |
beac1dff |
761 | if ($tag->{signature} ne DBM::Deep->SIG_BLIST) { |
762 | my $content = $tag->{content}; |
763 | my $start; |
764 | if ($obj->{return_next}) { $start = 0; } |
765 | else { $start = ord(substr($obj->{prev_md5}, $ch, 1)); } |
d0b74c17 |
766 | |
beac1dff |
767 | for (my $index = $start; $index < 256; $index++) { |
768 | my $subloc = unpack($self->{long_pack}, substr($content, $index * $self->{long_size}, $self->{long_size}) ); |
769 | if ($subloc) { |
770 | my $result = $self->traverse_index( $obj, $subloc, $ch + 1, $force_return_next ); |
771 | if (defined($result)) { return $result; } |
772 | } |
773 | } # index loop |
d0b74c17 |
774 | |
beac1dff |
775 | $obj->{return_next} = 1; |
776 | } # tag is an index |
d0b74c17 |
777 | |
beac1dff |
778 | elsif ($tag->{signature} eq DBM::Deep->SIG_BLIST) { |
779 | my $keys = $tag->{content}; |
780 | if ($force_return_next) { $obj->{return_next} = 1; } |
d0b74c17 |
781 | |
beac1dff |
782 | ## |
783 | # Iterate through buckets, looking for a key match |
784 | ## |
785 | for (my $i=0; $i<$self->{max_buckets}; $i++) { |
786 | my $key = substr($keys, $i * $self->{bucket_size}, $self->{hash_size}); |
787 | my $subloc = unpack($self->{long_pack}, substr($keys, ($i * $self->{bucket_size}) + $self->{hash_size}, $self->{long_size})); |
d0b74c17 |
788 | |
beac1dff |
789 | if (!$subloc) { |
790 | ## |
791 | # End of bucket list -- return to outer loop |
792 | ## |
793 | $obj->{return_next} = 1; |
794 | last; |
795 | } |
796 | elsif ($key eq $obj->{prev_md5}) { |
797 | ## |
798 | # Located previous key -- return next one found |
799 | ## |
800 | $obj->{return_next} = 1; |
801 | next; |
802 | } |
803 | elsif ($obj->{return_next}) { |
804 | ## |
805 | # Seek to bucket location and skip over signature |
806 | ## |
807 | seek($fh, $subloc + DBM::Deep->SIG_SIZE + $obj->_root->{file_offset}, SEEK_SET); |
d0b74c17 |
808 | |
beac1dff |
809 | ## |
810 | # Skip over value to get to plain key |
811 | ## |
812 | my $size; |
813 | read( $fh, $size, $self->{data_size}); $size = unpack($self->{data_pack}, $size); |
814 | if ($size) { seek($fh, $size, SEEK_CUR); } |
d0b74c17 |
815 | |
beac1dff |
816 | ## |
817 | # Read in plain key and return as scalar |
818 | ## |
819 | my $plain_key; |
820 | read( $fh, $size, $self->{data_size}); $size = unpack($self->{data_pack}, $size); |
821 | if ($size) { read( $fh, $plain_key, $size); } |
d0b74c17 |
822 | |
beac1dff |
823 | return $plain_key; |
824 | } |
825 | } # bucket loop |
d0b74c17 |
826 | |
beac1dff |
827 | $obj->{return_next} = 1; |
828 | } # tag is a bucket list |
d0b74c17 |
829 | |
beac1dff |
830 | return; |
6736c116 |
831 | } |
832 | |
833 | sub get_next_key { |
beac1dff |
834 | ## |
835 | # Locate next key, given digested previous one |
836 | ## |
6736c116 |
837 | my $self = shift; |
838 | my ($obj) = @_; |
d0b74c17 |
839 | |
beac1dff |
840 | $obj->{prev_md5} = $_[1] ? $_[1] : undef; |
841 | $obj->{return_next} = 0; |
d0b74c17 |
842 | |
beac1dff |
843 | ## |
844 | # If the previous key was not specifed, start at the top and |
845 | # return the first one found. |
846 | ## |
847 | if (!$obj->{prev_md5}) { |
848 | $obj->{prev_md5} = chr(0) x $self->{hash_size}; |
849 | $obj->{return_next} = 1; |
850 | } |
d0b74c17 |
851 | |
beac1dff |
852 | return $self->traverse_index( $obj, $obj->_base_offset, 0 ); |
6736c116 |
853 | } |
854 | |
a20d9a3f |
855 | 1; |
856 | __END__ |