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e1a479c5 |
1 | /* mro.c |
2 | * |
3 | * Copyright (c) 2007 Brandon L Black |
4 | * |
5 | * You may distribute under the terms of either the GNU General Public |
6 | * License or the Artistic License, as specified in the README file. |
7 | * |
8 | */ |
9 | |
10 | /* |
cac98860 |
11 | * "Which order shall we go in?" said Frodo. "Eldest first, or quickest first? |
12 | * You'll be last either way, Master Peregrin." |
13 | */ |
14 | |
15 | /* |
e1a479c5 |
16 | =head1 MRO Functions |
17 | |
18 | These functions are related to the method resolution order of perl classes |
19 | |
20 | =cut |
21 | */ |
22 | |
23 | #include "EXTERN.h" |
24 | #include "perl.h" |
25 | |
26 | struct mro_meta* |
27 | Perl_mro_meta_init(pTHX_ HV* stash) |
28 | { |
9fe4aecf |
29 | struct mro_meta* newmeta; |
e1a479c5 |
30 | |
31 | assert(stash); |
32 | assert(HvAUX(stash)); |
33 | assert(!(HvAUX(stash)->xhv_mro_meta)); |
183086be |
34 | Newxz(newmeta, 1, struct mro_meta); |
9fe4aecf |
35 | HvAUX(stash)->xhv_mro_meta = newmeta; |
dd69841b |
36 | newmeta->cache_gen = 1; |
e1a479c5 |
37 | |
38 | return newmeta; |
39 | } |
40 | |
41 | #if defined(USE_ITHREADS) |
42 | |
43 | /* for sv_dup on new threads */ |
44 | struct mro_meta* |
45 | Perl_mro_meta_dup(pTHX_ struct mro_meta* smeta, CLONE_PARAMS* param) |
46 | { |
e1a479c5 |
47 | struct mro_meta* newmeta; |
48 | |
49 | assert(smeta); |
50 | |
33e12d9d |
51 | Newx(newmeta, 1, struct mro_meta); |
52 | Copy(smeta, newmeta, 1, struct mro_meta); |
53 | |
54 | if (newmeta->mro_linear_dfs) |
55 | newmeta->mro_linear_dfs |
56 | = (AV*) SvREFCNT_inc(sv_dup((SV*)newmeta->mro_linear_dfs, param)); |
57 | if (newmeta->mro_linear_c3) |
58 | newmeta->mro_linear_c3 |
59 | = (AV*) SvREFCNT_inc(sv_dup((SV*)newmeta->mro_linear_c3, param)); |
33e12d9d |
60 | if (newmeta->mro_nextmethod) |
61 | newmeta->mro_nextmethod |
62 | = (HV*) SvREFCNT_inc(sv_dup((SV*)newmeta->mro_nextmethod, param)); |
e1a479c5 |
63 | |
64 | return newmeta; |
65 | } |
66 | |
67 | #endif /* USE_ITHREADS */ |
68 | |
69 | /* |
70 | =for apidoc mro_get_linear_isa_dfs |
71 | |
72 | Returns the Depth-First Search linearization of @ISA |
73 | the given stash. The return value is a read-only AV*. |
74 | C<level> should be 0 (it is used internally in this |
75 | function's recursion). |
76 | |
1c908217 |
77 | You are responsible for C<SvREFCNT_inc()> on the |
78 | return value if you plan to store it anywhere |
79 | semi-permanently (otherwise it might be deleted |
80 | out from under you the next time the cache is |
81 | invalidated). |
82 | |
e1a479c5 |
83 | =cut |
84 | */ |
85 | AV* |
86 | Perl_mro_get_linear_isa_dfs(pTHX_ HV *stash, I32 level) |
87 | { |
88 | AV* retval; |
89 | GV** gvp; |
90 | GV* gv; |
91 | AV* av; |
e1a479c5 |
92 | const char* stashname; |
93 | struct mro_meta* meta; |
94 | |
95 | assert(stash); |
96 | assert(HvAUX(stash)); |
97 | |
98 | stashname = HvNAME_get(stash); |
99 | if (!stashname) |
1e05feb3 |
100 | Perl_croak(aTHX_ "Can't linearize anonymous symbol table"); |
e1a479c5 |
101 | |
102 | if (level > 100) |
103 | Perl_croak(aTHX_ "Recursive inheritance detected in package '%s'", |
104 | stashname); |
105 | |
106 | meta = HvMROMETA(stash); |
1c908217 |
107 | |
108 | /* return cache if valid */ |
e1a479c5 |
109 | if((retval = meta->mro_linear_dfs)) { |
e1a479c5 |
110 | return retval; |
111 | } |
112 | |
113 | /* not in cache, make a new one */ |
1c908217 |
114 | |
e1a479c5 |
115 | retval = newAV(); |
116 | av_push(retval, newSVpv(stashname, 0)); /* add ourselves at the top */ |
117 | |
1c908217 |
118 | /* fetch our @ISA */ |
e1a479c5 |
119 | gvp = (GV**)hv_fetchs(stash, "ISA", FALSE); |
120 | av = (gvp && (gv = *gvp) && isGV_with_GP(gv)) ? GvAV(gv) : NULL; |
121 | |
640da897 |
122 | if(av && AvFILLp(av) >= 0) { |
1c908217 |
123 | |
124 | /* "stored" is used to keep track of all of the classnames |
125 | we have added to the MRO so far, so we can do a quick |
126 | exists check and avoid adding duplicate classnames to |
127 | the MRO as we go. */ |
128 | |
1e05feb3 |
129 | HV* const stored = (HV*)sv_2mortal((SV*)newHV()); |
ffd8da72 |
130 | SV **svp = AvARRAY(av); |
131 | I32 items = AvFILLp(av) + 1; |
1c908217 |
132 | |
133 | /* foreach(@ISA) */ |
e1a479c5 |
134 | while (items--) { |
135 | SV* const sv = *svp++; |
136 | HV* const basestash = gv_stashsv(sv, 0); |
ffd8da72 |
137 | SV *const *subrv_p; |
138 | I32 subrv_items; |
e1a479c5 |
139 | |
140 | if (!basestash) { |
1c908217 |
141 | /* if no stash exists for this @ISA member, |
142 | simply add it to the MRO and move on */ |
ffd8da72 |
143 | subrv_p = &sv; |
144 | subrv_items = 1; |
e1a479c5 |
145 | } |
146 | else { |
1c908217 |
147 | /* otherwise, recurse into ourselves for the MRO |
148 | of this @ISA member, and append their MRO to ours */ |
ffd8da72 |
149 | const AV *const subrv |
150 | = mro_get_linear_isa_dfs(basestash, level + 1); |
151 | |
152 | subrv_p = AvARRAY(subrv); |
153 | subrv_items = AvFILLp(subrv) + 1; |
154 | } |
155 | while(subrv_items--) { |
156 | SV *const subsv = *subrv_p++; |
157 | if(!hv_exists_ent(stored, subsv, 0)) { |
ffd8da72 |
158 | hv_store_ent(stored, subsv, &PL_sv_undef, 0); |
25270bc0 |
159 | av_push(retval, newSVsv(subsv)); |
ffd8da72 |
160 | } |
e1a479c5 |
161 | } |
162 | } |
163 | } |
164 | |
1c908217 |
165 | /* we don't want anyone modifying the cache entry but us, |
166 | and we do so by replacing it completely */ |
e1a479c5 |
167 | SvREADONLY_on(retval); |
1c908217 |
168 | |
e1a479c5 |
169 | meta->mro_linear_dfs = retval; |
170 | return retval; |
171 | } |
172 | |
173 | /* |
174 | =for apidoc mro_get_linear_isa_c3 |
175 | |
176 | Returns the C3 linearization of @ISA |
177 | the given stash. The return value is a read-only AV*. |
178 | C<level> should be 0 (it is used internally in this |
179 | function's recursion). |
180 | |
1c908217 |
181 | You are responsible for C<SvREFCNT_inc()> on the |
182 | return value if you plan to store it anywhere |
183 | semi-permanently (otherwise it might be deleted |
184 | out from under you the next time the cache is |
185 | invalidated). |
186 | |
e1a479c5 |
187 | =cut |
188 | */ |
189 | |
190 | AV* |
191 | Perl_mro_get_linear_isa_c3(pTHX_ HV* stash, I32 level) |
192 | { |
193 | AV* retval; |
194 | GV** gvp; |
195 | GV* gv; |
196 | AV* isa; |
197 | const char* stashname; |
198 | STRLEN stashname_len; |
199 | struct mro_meta* meta; |
200 | |
201 | assert(stash); |
202 | assert(HvAUX(stash)); |
203 | |
204 | stashname = HvNAME_get(stash); |
205 | stashname_len = HvNAMELEN_get(stash); |
206 | if (!stashname) |
1e05feb3 |
207 | Perl_croak(aTHX_ "Can't linearize anonymous symbol table"); |
e1a479c5 |
208 | |
209 | if (level > 100) |
210 | Perl_croak(aTHX_ "Recursive inheritance detected in package '%s'", |
211 | stashname); |
212 | |
213 | meta = HvMROMETA(stash); |
1c908217 |
214 | |
215 | /* return cache if valid */ |
e1a479c5 |
216 | if((retval = meta->mro_linear_c3)) { |
e1a479c5 |
217 | return retval; |
218 | } |
219 | |
220 | /* not in cache, make a new one */ |
221 | |
e1a479c5 |
222 | gvp = (GV**)hv_fetchs(stash, "ISA", FALSE); |
223 | isa = (gvp && (gv = *gvp) && isGV_with_GP(gv)) ? GvAV(gv) : NULL; |
224 | |
1c908217 |
225 | /* For a better idea how the rest of this works, see the much clearer |
226 | pure perl version in Algorithm::C3 0.01: |
227 | http://search.cpan.org/src/STEVAN/Algorithm-C3-0.01/lib/Algorithm/C3.pm |
228 | (later versions go about it differently than this code for speed reasons) |
229 | */ |
8638e433 |
230 | |
e1a479c5 |
231 | if(isa && AvFILLp(isa) >= 0) { |
232 | SV** seqs_ptr; |
233 | I32 seqs_items; |
1e05feb3 |
234 | HV* const tails = (HV*)sv_2mortal((SV*)newHV()); |
235 | AV* const seqs = (AV*)sv_2mortal((SV*)newAV()); |
8638e433 |
236 | I32* heads; |
237 | |
238 | /* This builds @seqs, which is an array of arrays. |
239 | The members of @seqs are the MROs of |
240 | the members of @ISA, followed by @ISA itself. |
241 | */ |
e1a479c5 |
242 | I32 items = AvFILLp(isa) + 1; |
243 | SV** isa_ptr = AvARRAY(isa); |
244 | while(items--) { |
245 | AV* isa_lin; |
1e05feb3 |
246 | SV* const isa_item = *isa_ptr++; |
247 | HV* const isa_item_stash = gv_stashsv(isa_item, 0); |
e1a479c5 |
248 | if(!isa_item_stash) { |
8638e433 |
249 | /* if no stash, make a temporary fake MRO |
250 | containing just itself */ |
251 | isa_lin = (AV*)sv_2mortal((SV*)newAV()); |
e1a479c5 |
252 | av_push(isa_lin, newSVsv(isa_item)); |
253 | } |
254 | else { |
255 | isa_lin = mro_get_linear_isa_c3(isa_item_stash, level + 1); /* recursion */ |
256 | } |
1dcae283 |
257 | av_push(seqs, SvREFCNT_inc_simple_NN((SV*)isa_lin)); |
e1a479c5 |
258 | } |
1dcae283 |
259 | av_push(seqs, SvREFCNT_inc_simple_NN((SV*)isa)); |
8638e433 |
260 | |
261 | /* This builds "heads", which as an array of integer array |
262 | indices, one per seq, which point at the virtual "head" |
263 | of the seq (initially zero) */ |
264 | Newxz(heads, AvFILLp(seqs)+1, I32); |
265 | |
266 | /* This builds %tails, which has one key for every class |
267 | mentioned in the tail of any sequence in @seqs (tail meaning |
268 | everything after the first class, the "head"). The value |
269 | is how many times this key appears in the tails of @seqs. |
270 | */ |
e1a479c5 |
271 | seqs_ptr = AvARRAY(seqs); |
272 | seqs_items = AvFILLp(seqs) + 1; |
273 | while(seqs_items--) { |
1e05feb3 |
274 | AV* const seq = (AV*)*seqs_ptr++; |
e1a479c5 |
275 | I32 seq_items = AvFILLp(seq); |
276 | if(seq_items > 0) { |
277 | SV** seq_ptr = AvARRAY(seq) + 1; |
278 | while(seq_items--) { |
1e05feb3 |
279 | SV* const seqitem = *seq_ptr++; |
280 | HE* const he = hv_fetch_ent(tails, seqitem, 0, 0); |
e1a479c5 |
281 | if(!he) { |
282 | hv_store_ent(tails, seqitem, newSViv(1), 0); |
283 | } |
284 | else { |
1e05feb3 |
285 | SV* const val = HeVAL(he); |
e1a479c5 |
286 | sv_inc(val); |
287 | } |
288 | } |
289 | } |
290 | } |
291 | |
1dcae283 |
292 | /* Initialize retval to build the return value in */ |
293 | retval = newAV(); |
294 | av_push(retval, newSVpvn(stashname, stashname_len)); /* us first */ |
295 | |
8638e433 |
296 | /* This loop won't terminate until we either finish building |
297 | the MRO, or get an exception. */ |
e1a479c5 |
298 | while(1) { |
e1a479c5 |
299 | SV* cand = NULL; |
300 | SV* winner = NULL; |
8638e433 |
301 | int s; |
302 | |
303 | /* "foreach $seq (@seqs)" */ |
1e05feb3 |
304 | SV** const avptr = AvARRAY(seqs); |
8638e433 |
305 | for(s = 0; s <= AvFILLp(seqs); s++) { |
e1a479c5 |
306 | SV** svp; |
1e05feb3 |
307 | AV * const seq = (AV*)(avptr[s]); |
308 | SV* seqhead; |
8638e433 |
309 | if(!seq) continue; /* skip empty seqs */ |
310 | svp = av_fetch(seq, heads[s], 0); |
311 | seqhead = *svp; /* seqhead = head of this seq */ |
e1a479c5 |
312 | if(!winner) { |
1e05feb3 |
313 | HE* tail_entry; |
314 | SV* val; |
8638e433 |
315 | /* if we haven't found a winner for this round yet, |
316 | and this seqhead is not in tails (or the count |
317 | for it in tails has dropped to zero), then this |
318 | seqhead is our new winner, and is added to the |
319 | final MRO immediately */ |
e1a479c5 |
320 | cand = seqhead; |
321 | if((tail_entry = hv_fetch_ent(tails, cand, 0, 0)) |
322 | && (val = HeVAL(tail_entry)) |
25270bc0 |
323 | && (SvIVX(val) > 0)) |
e1a479c5 |
324 | continue; |
325 | winner = newSVsv(cand); |
326 | av_push(retval, winner); |
8638e433 |
327 | /* note however that even when we find a winner, |
328 | we continue looping over @seqs to do housekeeping */ |
e1a479c5 |
329 | } |
330 | if(!sv_cmp(seqhead, winner)) { |
8638e433 |
331 | /* Once we have a winner (including the iteration |
332 | where we first found him), inc the head ptr |
333 | for any seq which had the winner as a head, |
334 | NULL out any seq which is now empty, |
335 | and adjust tails for consistency */ |
336 | |
1e05feb3 |
337 | const int new_head = ++heads[s]; |
8638e433 |
338 | if(new_head > AvFILLp(seq)) { |
1dcae283 |
339 | SvREFCNT_dec(avptr[s]); |
8638e433 |
340 | avptr[s] = NULL; |
341 | } |
342 | else { |
1e05feb3 |
343 | HE* tail_entry; |
344 | SV* val; |
8638e433 |
345 | /* Because we know this new seqhead used to be |
346 | a tail, we can assume it is in tails and has |
347 | a positive value, which we need to dec */ |
348 | svp = av_fetch(seq, new_head, 0); |
349 | seqhead = *svp; |
350 | tail_entry = hv_fetch_ent(tails, seqhead, 0, 0); |
351 | val = HeVAL(tail_entry); |
352 | sv_dec(val); |
353 | } |
e1a479c5 |
354 | } |
355 | } |
8638e433 |
356 | |
357 | /* if we found no candidates, we are done building the MRO. |
358 | !cand means no seqs have any entries left to check */ |
359 | if(!cand) { |
360 | Safefree(heads); |
361 | break; |
362 | } |
363 | |
364 | /* If we had candidates, but nobody won, then the @ISA |
365 | hierarchy is not C3-incompatible */ |
e1a479c5 |
366 | if(!winner) { |
8638e433 |
367 | /* we have to do some cleanup before we croak */ |
8638e433 |
368 | |
e1a479c5 |
369 | SvREFCNT_dec(retval); |
8638e433 |
370 | Safefree(heads); |
371 | |
e1a479c5 |
372 | Perl_croak(aTHX_ "Inconsistent hierarchy during C3 merge of class '%s': " |
373 | "merging failed on parent '%"SVf"'", stashname, SVfARG(cand)); |
374 | } |
375 | } |
376 | } |
1dcae283 |
377 | else { /* @ISA was undefined or empty */ |
378 | /* build a retval containing only ourselves */ |
379 | retval = newAV(); |
380 | av_push(retval, newSVpvn(stashname, stashname_len)); |
381 | } |
e1a479c5 |
382 | |
1c908217 |
383 | /* we don't want anyone modifying the cache entry but us, |
384 | and we do so by replacing it completely */ |
e1a479c5 |
385 | SvREADONLY_on(retval); |
1c908217 |
386 | |
e1a479c5 |
387 | meta->mro_linear_c3 = retval; |
388 | return retval; |
389 | } |
390 | |
391 | /* |
392 | =for apidoc mro_get_linear_isa |
393 | |
394 | Returns either C<mro_get_linear_isa_c3> or |
395 | C<mro_get_linear_isa_dfs> for the given stash, |
396 | dependant upon which MRO is in effect |
397 | for that stash. The return value is a |
398 | read-only AV*. |
399 | |
1c908217 |
400 | You are responsible for C<SvREFCNT_inc()> on the |
401 | return value if you plan to store it anywhere |
402 | semi-permanently (otherwise it might be deleted |
403 | out from under you the next time the cache is |
404 | invalidated). |
405 | |
e1a479c5 |
406 | =cut |
407 | */ |
408 | AV* |
409 | Perl_mro_get_linear_isa(pTHX_ HV *stash) |
410 | { |
411 | struct mro_meta* meta; |
412 | assert(stash); |
413 | assert(HvAUX(stash)); |
414 | |
415 | meta = HvMROMETA(stash); |
416 | if(meta->mro_which == MRO_DFS) { |
417 | return mro_get_linear_isa_dfs(stash, 0); |
418 | } else if(meta->mro_which == MRO_C3) { |
419 | return mro_get_linear_isa_c3(stash, 0); |
420 | } else { |
14f97ce6 |
421 | Perl_croak(aTHX_ "panic: invalid MRO!"); |
e1a479c5 |
422 | } |
7caa839c |
423 | return NULL; /* NOT REACHED */ |
e1a479c5 |
424 | } |
425 | |
426 | /* |
427 | =for apidoc mro_isa_changed_in |
428 | |
1c908217 |
429 | Takes the necessary steps (cache invalidations, mostly) |
e1a479c5 |
430 | when the @ISA of the given package has changed. Invoked |
431 | by the C<setisa> magic, should not need to invoke directly. |
432 | |
433 | =cut |
434 | */ |
435 | void |
436 | Perl_mro_isa_changed_in(pTHX_ HV* stash) |
437 | { |
438 | dVAR; |
439 | HV* isarev; |
440 | AV* linear_mro; |
441 | HE* iter; |
442 | SV** svp; |
443 | I32 items; |
1e05feb3 |
444 | bool is_universal; |
e1a479c5 |
445 | |
1e05feb3 |
446 | const char * const stashname = HvNAME_get(stash); |
447 | const STRLEN stashname_len = HvNAMELEN_get(stash); |
e1a479c5 |
448 | |
449 | /* wipe out the cached linearizations for this stash */ |
1e05feb3 |
450 | struct mro_meta * const meta = HvMROMETA(stash); |
e1a479c5 |
451 | SvREFCNT_dec((SV*)meta->mro_linear_dfs); |
452 | SvREFCNT_dec((SV*)meta->mro_linear_c3); |
453 | meta->mro_linear_dfs = NULL; |
454 | meta->mro_linear_c3 = NULL; |
455 | |
456 | /* Wipe the global method cache if this package |
457 | is UNIVERSAL or one of its parents */ |
dd69841b |
458 | |
459 | svp = hv_fetch(PL_isarev, stashname, stashname_len, 0); |
460 | isarev = svp ? (HV*)*svp : NULL; |
461 | |
462 | if((stashname_len == 9 && strEQ(stashname, "UNIVERSAL")) |
463 | || (isarev && hv_exists(isarev, "UNIVERSAL", 9))) { |
e1a479c5 |
464 | PL_sub_generation++; |
dd69841b |
465 | is_universal = TRUE; |
466 | } |
1e05feb3 |
467 | else { /* Wipe the local method cache otherwise */ |
dd69841b |
468 | meta->cache_gen++; |
1e05feb3 |
469 | is_universal = FALSE; |
470 | } |
e1a479c5 |
471 | |
472 | /* wipe next::method cache too */ |
473 | if(meta->mro_nextmethod) hv_clear(meta->mro_nextmethod); |
1e05feb3 |
474 | |
e1a479c5 |
475 | /* Iterate the isarev (classes that are our children), |
476 | wiping out their linearization and method caches */ |
dd69841b |
477 | if(isarev) { |
e1a479c5 |
478 | hv_iterinit(isarev); |
479 | while((iter = hv_iternext(isarev))) { |
1e05feb3 |
480 | SV* const revkey = hv_iterkeysv(iter); |
e1a479c5 |
481 | HV* revstash = gv_stashsv(revkey, 0); |
bc2cbbac |
482 | struct mro_meta* revmeta; |
483 | |
484 | if(!revstash) continue; |
485 | revmeta = HvMROMETA(revstash); |
e1a479c5 |
486 | SvREFCNT_dec((SV*)revmeta->mro_linear_dfs); |
487 | SvREFCNT_dec((SV*)revmeta->mro_linear_c3); |
488 | revmeta->mro_linear_dfs = NULL; |
489 | revmeta->mro_linear_c3 = NULL; |
dd69841b |
490 | if(!is_universal) |
491 | revmeta->cache_gen++; |
e1a479c5 |
492 | if(revmeta->mro_nextmethod) |
493 | hv_clear(revmeta->mro_nextmethod); |
494 | } |
495 | } |
496 | |
1c908217 |
497 | /* Now iterate our MRO (parents), and do a few things: |
498 | 1) instantiate with the "fake" flag if they don't exist |
499 | 2) flag them as universal if we are universal |
500 | 3) Add everything from our isarev to their isarev |
501 | */ |
502 | |
503 | /* We're starting at the 2nd element, skipping ourselves here */ |
e1a479c5 |
504 | linear_mro = mro_get_linear_isa(stash); |
505 | svp = AvARRAY(linear_mro) + 1; |
506 | items = AvFILLp(linear_mro); |
1c908217 |
507 | |
e1a479c5 |
508 | while (items--) { |
509 | SV* const sv = *svp++; |
e1a479c5 |
510 | HV* mroisarev; |
511 | |
1e05feb3 |
512 | HE *he = hv_fetch_ent(PL_isarev, sv, 0, 0); |
dd69841b |
513 | if(!he) { |
514 | he = hv_store_ent(PL_isarev, sv, (SV*)newHV(), 0); |
e1a479c5 |
515 | } |
dd69841b |
516 | mroisarev = (HV*)HeVAL(he); |
e1a479c5 |
517 | |
25270bc0 |
518 | /* This hash only ever contains PL_sv_yes. Storing it over itself is |
519 | almost as cheap as calling hv_exists, so on aggregate we expect to |
520 | save time by not making two calls to the common HV code for the |
521 | case where it doesn't exist. */ |
522 | |
dd69841b |
523 | hv_store(mroisarev, stashname, stashname_len, &PL_sv_yes, 0); |
e1a479c5 |
524 | |
525 | if(isarev) { |
526 | hv_iterinit(isarev); |
527 | while((iter = hv_iternext(isarev))) { |
dd69841b |
528 | I32 revkeylen; |
1e05feb3 |
529 | char* const revkey = hv_iterkey(iter, &revkeylen); |
dd69841b |
530 | hv_store(mroisarev, revkey, revkeylen, &PL_sv_yes, 0); |
e1a479c5 |
531 | } |
532 | } |
533 | } |
534 | } |
535 | |
536 | /* |
537 | =for apidoc mro_method_changed_in |
538 | |
47c9dd14 |
539 | Invalidates method caching on any child classes |
540 | of the given stash, so that they might notice |
541 | the changes in this one. |
e1a479c5 |
542 | |
543 | Ideally, all instances of C<PL_sub_generation++> in |
dd69841b |
544 | perl source outside of C<mro.c> should be |
545 | replaced by calls to this. |
546 | |
547 | Perl automatically handles most of the common |
548 | ways a method might be redefined. However, there |
549 | are a few ways you could change a method in a stash |
550 | without the cache code noticing, in which case you |
551 | need to call this method afterwards: |
e1a479c5 |
552 | |
dd69841b |
553 | 1) Directly manipulating the stash HV entries from |
554 | XS code. |
e1a479c5 |
555 | |
dd69841b |
556 | 2) Assigning a reference to a readonly scalar |
557 | constant into a stash entry in order to create |
558 | a constant subroutine (like constant.pm |
559 | does). |
560 | |
561 | This same method is available from pure perl |
562 | via, C<mro::method_changed_in(classname)>. |
e1a479c5 |
563 | |
564 | =cut |
565 | */ |
566 | void |
567 | Perl_mro_method_changed_in(pTHX_ HV *stash) |
568 | { |
1e05feb3 |
569 | const char * const stashname = HvNAME_get(stash); |
570 | const STRLEN stashname_len = HvNAMELEN_get(stash); |
dd69841b |
571 | |
1e05feb3 |
572 | SV ** const svp = hv_fetch(PL_isarev, stashname, stashname_len, 0); |
573 | HV * const isarev = svp ? (HV*)*svp : NULL; |
e1a479c5 |
574 | |
575 | /* If stash is UNIVERSAL, or one of UNIVERSAL's parents, |
576 | invalidate all method caches globally */ |
dd69841b |
577 | if((stashname_len == 9 && strEQ(stashname, "UNIVERSAL")) |
578 | || (isarev && hv_exists(isarev, "UNIVERSAL", 9))) { |
e1a479c5 |
579 | PL_sub_generation++; |
580 | return; |
581 | } |
582 | |
583 | /* else, invalidate the method caches of all child classes, |
584 | but not itself */ |
dd69841b |
585 | if(isarev) { |
1e05feb3 |
586 | HE* iter; |
587 | |
e1a479c5 |
588 | hv_iterinit(isarev); |
589 | while((iter = hv_iternext(isarev))) { |
1e05feb3 |
590 | SV* const revkey = hv_iterkeysv(iter); |
591 | HV* const revstash = gv_stashsv(revkey, 0); |
bc2cbbac |
592 | struct mro_meta* mrometa; |
593 | |
594 | if(!revstash) continue; |
595 | mrometa = HvMROMETA(revstash); |
dd69841b |
596 | mrometa->cache_gen++; |
e1a479c5 |
597 | if(mrometa->mro_nextmethod) |
598 | hv_clear(mrometa->mro_nextmethod); |
599 | } |
600 | } |
601 | } |
602 | |
603 | /* These two are static helpers for next::method and friends, |
604 | and re-implement a bunch of the code from pp_caller() in |
605 | a more efficient manner for this particular usage. |
606 | */ |
607 | |
608 | STATIC I32 |
609 | __dopoptosub_at(const PERL_CONTEXT *cxstk, I32 startingblock) { |
610 | I32 i; |
611 | for (i = startingblock; i >= 0; i--) { |
612 | if(CxTYPE((PERL_CONTEXT*)(&cxstk[i])) == CXt_SUB) return i; |
613 | } |
614 | return i; |
615 | } |
616 | |
617 | STATIC SV* |
618 | __nextcan(pTHX_ SV* self, I32 throw_nomethod) |
619 | { |
620 | register I32 cxix; |
621 | register const PERL_CONTEXT *ccstack = cxstack; |
622 | const PERL_SI *top_si = PL_curstackinfo; |
623 | HV* selfstash; |
e1a479c5 |
624 | SV *stashname; |
625 | const char *fq_subname; |
626 | const char *subname; |
e1a479c5 |
627 | STRLEN stashname_len; |
628 | STRLEN subname_len; |
629 | SV* sv; |
630 | GV** gvp; |
631 | AV* linear_av; |
632 | SV** linear_svp; |
e1a479c5 |
633 | const char *hvname; |
634 | I32 items; |
635 | struct mro_meta* selfmeta; |
636 | HV* nmcache; |
e1a479c5 |
637 | |
638 | if(sv_isobject(self)) |
639 | selfstash = SvSTASH(SvRV(self)); |
640 | else |
641 | selfstash = gv_stashsv(self, 0); |
642 | |
643 | assert(selfstash); |
644 | |
645 | hvname = HvNAME_get(selfstash); |
646 | if (!hvname) |
647 | Perl_croak(aTHX_ "Can't use anonymous symbol table for method lookup"); |
648 | |
649 | cxix = __dopoptosub_at(cxstack, cxstack_ix); |
650 | |
651 | /* This block finds the contextually-enclosing fully-qualified subname, |
652 | much like looking at (caller($i))[3] until you find a real sub that |
653 | isn't ANON, etc */ |
654 | for (;;) { |
1e05feb3 |
655 | GV* cvgv; |
656 | STRLEN fq_subname_len; |
657 | |
e1a479c5 |
658 | /* we may be in a higher stacklevel, so dig down deeper */ |
659 | while (cxix < 0) { |
660 | if(top_si->si_type == PERLSI_MAIN) |
661 | Perl_croak(aTHX_ "next::method/next::can/maybe::next::method must be used in method context"); |
662 | top_si = top_si->si_prev; |
663 | ccstack = top_si->si_cxstack; |
664 | cxix = __dopoptosub_at(ccstack, top_si->si_cxix); |
665 | } |
666 | |
667 | if(CxTYPE((PERL_CONTEXT*)(&ccstack[cxix])) != CXt_SUB |
668 | || (PL_DBsub && GvCV(PL_DBsub) && ccstack[cxix].blk_sub.cv == GvCV(PL_DBsub))) { |
669 | cxix = __dopoptosub_at(ccstack, cxix - 1); |
670 | continue; |
671 | } |
672 | |
673 | { |
674 | const I32 dbcxix = __dopoptosub_at(ccstack, cxix - 1); |
675 | if (PL_DBsub && GvCV(PL_DBsub) && dbcxix >= 0 && ccstack[dbcxix].blk_sub.cv == GvCV(PL_DBsub)) { |
676 | if(CxTYPE((PERL_CONTEXT*)(&ccstack[dbcxix])) != CXt_SUB) { |
677 | cxix = dbcxix; |
678 | continue; |
679 | } |
680 | } |
681 | } |
682 | |
683 | cvgv = CvGV(ccstack[cxix].blk_sub.cv); |
684 | |
685 | if(!isGV(cvgv)) { |
686 | cxix = __dopoptosub_at(ccstack, cxix - 1); |
687 | continue; |
688 | } |
689 | |
690 | /* we found a real sub here */ |
691 | sv = sv_2mortal(newSV(0)); |
692 | |
693 | gv_efullname3(sv, cvgv, NULL); |
694 | |
695 | fq_subname = SvPVX(sv); |
696 | fq_subname_len = SvCUR(sv); |
697 | |
698 | subname = strrchr(fq_subname, ':'); |
699 | if(!subname) |
700 | Perl_croak(aTHX_ "next::method/next::can/maybe::next::method cannot find enclosing method"); |
701 | |
702 | subname++; |
703 | subname_len = fq_subname_len - (subname - fq_subname); |
704 | if(subname_len == 8 && strEQ(subname, "__ANON__")) { |
705 | cxix = __dopoptosub_at(ccstack, cxix - 1); |
706 | continue; |
707 | } |
708 | break; |
709 | } |
710 | |
711 | /* If we made it to here, we found our context */ |
712 | |
1c908217 |
713 | /* Initialize the next::method cache for this stash |
714 | if necessary */ |
e1a479c5 |
715 | selfmeta = HvMROMETA(selfstash); |
716 | if(!(nmcache = selfmeta->mro_nextmethod)) { |
717 | nmcache = selfmeta->mro_nextmethod = newHV(); |
718 | } |
1e05feb3 |
719 | else { /* Use the cached coderef if it exists */ |
720 | HE* cache_entry = hv_fetch_ent(nmcache, sv, 0, 0); |
721 | if (cache_entry) { |
722 | SV* const val = HeVAL(cache_entry); |
723 | if(val == &PL_sv_undef) { |
724 | if(throw_nomethod) |
725 | Perl_croak(aTHX_ "No next::method '%s' found for %s", subname, hvname); |
726 | } |
727 | return val; |
728 | } |
e1a479c5 |
729 | } |
730 | |
731 | /* beyond here is just for cache misses, so perf isn't as critical */ |
732 | |
733 | stashname_len = subname - fq_subname - 2; |
734 | stashname = sv_2mortal(newSVpvn(fq_subname, stashname_len)); |
735 | |
736 | linear_av = mro_get_linear_isa_c3(selfstash, 0); /* has ourselves at the top of the list */ |
737 | |
738 | linear_svp = AvARRAY(linear_av); |
739 | items = AvFILLp(linear_av) + 1; |
740 | |
1c908217 |
741 | /* Walk down our MRO, skipping everything up |
742 | to the contextually enclosing class */ |
e1a479c5 |
743 | while (items--) { |
1e05feb3 |
744 | SV * const linear_sv = *linear_svp++; |
e1a479c5 |
745 | assert(linear_sv); |
746 | if(sv_eq(linear_sv, stashname)) |
747 | break; |
748 | } |
749 | |
1c908217 |
750 | /* Now search the remainder of the MRO for the |
751 | same method name as the contextually enclosing |
752 | method */ |
e1a479c5 |
753 | if(items > 0) { |
754 | while (items--) { |
1e05feb3 |
755 | SV * const linear_sv = *linear_svp++; |
756 | HV* curstash; |
757 | GV* candidate; |
758 | CV* cand_cv; |
759 | |
e1a479c5 |
760 | assert(linear_sv); |
761 | curstash = gv_stashsv(linear_sv, FALSE); |
762 | |
dd69841b |
763 | if (!curstash) { |
b0c482e3 |
764 | if (ckWARN(WARN_SYNTAX)) |
765 | Perl_warner(aTHX_ packWARN(WARN_SYNTAX), "Can't locate package %"SVf" for @%s::ISA", |
e1a479c5 |
766 | (void*)linear_sv, hvname); |
767 | continue; |
768 | } |
769 | |
770 | assert(curstash); |
771 | |
772 | gvp = (GV**)hv_fetch(curstash, subname, subname_len, 0); |
773 | if (!gvp) continue; |
774 | |
775 | candidate = *gvp; |
776 | assert(candidate); |
777 | |
778 | if (SvTYPE(candidate) != SVt_PVGV) |
779 | gv_init(candidate, curstash, subname, subname_len, TRUE); |
1c908217 |
780 | |
781 | /* Notably, we only look for real entries, not method cache |
782 | entries, because in C3 the method cache of a parent is not |
783 | valid for the child */ |
e1a479c5 |
784 | if (SvTYPE(candidate) == SVt_PVGV && (cand_cv = GvCV(candidate)) && !GvCVGEN(candidate)) { |
785 | SvREFCNT_inc_simple_void_NN((SV*)cand_cv); |
786 | hv_store_ent(nmcache, newSVsv(sv), (SV*)cand_cv, 0); |
787 | return (SV*)cand_cv; |
788 | } |
789 | } |
790 | } |
791 | |
792 | hv_store_ent(nmcache, newSVsv(sv), &PL_sv_undef, 0); |
793 | if(throw_nomethod) |
794 | Perl_croak(aTHX_ "No next::method '%s' found for %s", subname, hvname); |
795 | return &PL_sv_undef; |
796 | } |
797 | |
798 | #include "XSUB.h" |
799 | |
800 | XS(XS_mro_get_linear_isa); |
801 | XS(XS_mro_set_mro); |
802 | XS(XS_mro_get_mro); |
803 | XS(XS_mro_get_isarev); |
804 | XS(XS_mro_is_universal); |
c5860d66 |
805 | XS(XS_mro_invalidate_method_caches); |
e1a479c5 |
806 | XS(XS_mro_method_changed_in); |
807 | XS(XS_next_can); |
808 | XS(XS_next_method); |
809 | XS(XS_maybe_next_method); |
810 | |
811 | void |
812 | Perl_boot_core_mro(pTHX) |
813 | { |
814 | dVAR; |
815 | static const char file[] = __FILE__; |
816 | |
817 | newXSproto("mro::get_linear_isa", XS_mro_get_linear_isa, file, "$;$"); |
818 | newXSproto("mro::set_mro", XS_mro_set_mro, file, "$$"); |
819 | newXSproto("mro::get_mro", XS_mro_get_mro, file, "$"); |
820 | newXSproto("mro::get_isarev", XS_mro_get_isarev, file, "$"); |
821 | newXSproto("mro::is_universal", XS_mro_is_universal, file, "$"); |
c5860d66 |
822 | newXSproto("mro::invalidate_all_method_caches", XS_mro_invalidate_method_caches, file, ""); |
e1a479c5 |
823 | newXSproto("mro::method_changed_in", XS_mro_method_changed_in, file, "$"); |
824 | newXS("next::can", XS_next_can, file); |
825 | newXS("next::method", XS_next_method, file); |
826 | newXS("maybe::next::method", XS_maybe_next_method, file); |
827 | } |
828 | |
829 | XS(XS_mro_get_linear_isa) { |
830 | dVAR; |
831 | dXSARGS; |
832 | AV* RETVAL; |
833 | HV* class_stash; |
834 | SV* classname; |
835 | |
836 | PERL_UNUSED_ARG(cv); |
837 | |
838 | if(items < 1 || items > 2) |
839 | Perl_croak(aTHX_ "Usage: mro::get_linear_isa(classname [, type ])"); |
840 | |
841 | classname = ST(0); |
842 | class_stash = gv_stashsv(classname, 0); |
843 | if(!class_stash) Perl_croak(aTHX_ "No such class: '%"SVf"'!", SVfARG(classname)); |
844 | |
845 | if(items > 1) { |
1e05feb3 |
846 | const char* const which = SvPV_nolen(ST(1)); |
e1a479c5 |
847 | if(strEQ(which, "dfs")) |
848 | RETVAL = mro_get_linear_isa_dfs(class_stash, 0); |
849 | else if(strEQ(which, "c3")) |
850 | RETVAL = mro_get_linear_isa_c3(class_stash, 0); |
851 | else |
852 | Perl_croak(aTHX_ "Invalid mro name: '%s'", which); |
853 | } |
854 | else { |
855 | RETVAL = mro_get_linear_isa(class_stash); |
856 | } |
857 | |
858 | ST(0) = newRV_inc((SV*)RETVAL); |
859 | sv_2mortal(ST(0)); |
860 | XSRETURN(1); |
861 | } |
862 | |
863 | XS(XS_mro_set_mro) |
864 | { |
865 | dVAR; |
866 | dXSARGS; |
867 | SV* classname; |
868 | char* whichstr; |
869 | mro_alg which; |
870 | HV* class_stash; |
871 | struct mro_meta* meta; |
872 | |
873 | PERL_UNUSED_ARG(cv); |
874 | |
875 | if (items != 2) |
876 | Perl_croak(aTHX_ "Usage: mro::set_mro(classname, type)"); |
877 | |
878 | classname = ST(0); |
879 | whichstr = SvPV_nolen(ST(1)); |
880 | class_stash = gv_stashsv(classname, GV_ADD); |
881 | if(!class_stash) Perl_croak(aTHX_ "Cannot create class: '%"SVf"'!", SVfARG(classname)); |
882 | meta = HvMROMETA(class_stash); |
883 | |
884 | if(strEQ(whichstr, "dfs")) |
885 | which = MRO_DFS; |
886 | else if(strEQ(whichstr, "c3")) |
887 | which = MRO_C3; |
888 | else |
889 | Perl_croak(aTHX_ "Invalid mro name: '%s'", whichstr); |
890 | |
891 | if(meta->mro_which != which) { |
892 | meta->mro_which = which; |
893 | /* Only affects local method cache, not |
894 | even child classes */ |
dd69841b |
895 | meta->cache_gen++; |
e1a479c5 |
896 | if(meta->mro_nextmethod) |
897 | hv_clear(meta->mro_nextmethod); |
898 | } |
899 | |
900 | XSRETURN_EMPTY; |
901 | } |
902 | |
903 | |
904 | XS(XS_mro_get_mro) |
905 | { |
906 | dVAR; |
907 | dXSARGS; |
908 | SV* classname; |
909 | HV* class_stash; |
910 | struct mro_meta* meta; |
911 | |
912 | PERL_UNUSED_ARG(cv); |
913 | |
914 | if (items != 1) |
915 | Perl_croak(aTHX_ "Usage: mro::get_mro(classname)"); |
916 | |
917 | classname = ST(0); |
918 | class_stash = gv_stashsv(classname, 0); |
919 | if(!class_stash) Perl_croak(aTHX_ "No such class: '%"SVf"'!", SVfARG(classname)); |
920 | meta = HvMROMETA(class_stash); |
921 | |
922 | if(meta->mro_which == MRO_DFS) |
923 | ST(0) = sv_2mortal(newSVpvn("dfs", 3)); |
924 | else |
925 | ST(0) = sv_2mortal(newSVpvn("c3", 2)); |
926 | |
927 | XSRETURN(1); |
928 | } |
929 | |
930 | XS(XS_mro_get_isarev) |
931 | { |
932 | dVAR; |
933 | dXSARGS; |
934 | SV* classname; |
935 | HV* class_stash; |
dd69841b |
936 | SV** svp; |
e1a479c5 |
937 | HV* isarev; |
dd69841b |
938 | char* stashname; |
939 | STRLEN stashname_len; |
e1a479c5 |
940 | |
941 | PERL_UNUSED_ARG(cv); |
942 | |
943 | if (items != 1) |
944 | Perl_croak(aTHX_ "Usage: mro::get_isarev(classname)"); |
945 | |
946 | classname = ST(0); |
947 | |
948 | class_stash = gv_stashsv(classname, 0); |
1e05feb3 |
949 | if(!class_stash) |
950 | Perl_croak(aTHX_ "No such class: '%"SVf"'!", SVfARG(classname)); |
e1a479c5 |
951 | |
952 | SP -= items; |
dd69841b |
953 | |
954 | stashname = HvNAME_get(class_stash); |
955 | stashname_len = HvNAMELEN_get(class_stash); |
956 | svp = hv_fetch(PL_isarev, stashname, stashname_len, 0); |
957 | isarev = svp ? (HV*)*svp : NULL; |
958 | if(isarev) { |
e1a479c5 |
959 | HE* iter; |
960 | hv_iterinit(isarev); |
961 | while((iter = hv_iternext(isarev))) |
962 | XPUSHs(hv_iterkeysv(iter)); |
963 | } |
964 | |
965 | PUTBACK; |
966 | return; |
967 | } |
968 | |
969 | XS(XS_mro_is_universal) |
970 | { |
971 | dVAR; |
972 | dXSARGS; |
973 | SV* classname; |
974 | HV* class_stash; |
dd69841b |
975 | HV* isarev; |
976 | char* stashname; |
977 | STRLEN stashname_len; |
978 | SV** svp; |
e1a479c5 |
979 | |
980 | PERL_UNUSED_ARG(cv); |
981 | |
982 | if (items != 1) |
dd69841b |
983 | Perl_croak(aTHX_ "Usage: mro::is_universal(classname)"); |
e1a479c5 |
984 | |
985 | classname = ST(0); |
986 | class_stash = gv_stashsv(classname, 0); |
987 | if(!class_stash) Perl_croak(aTHX_ "No such class: '%"SVf"'!", SVfARG(classname)); |
988 | |
dd69841b |
989 | stashname = HvNAME_get(class_stash); |
990 | stashname_len = HvNAMELEN_get(class_stash); |
991 | |
992 | svp = hv_fetch(PL_isarev, stashname, stashname_len, 0); |
993 | isarev = svp ? (HV*)*svp : NULL; |
994 | |
995 | if((stashname_len == 9 && strEQ(stashname, "UNIVERSAL")) |
996 | || (isarev && hv_exists(isarev, "UNIVERSAL", 9))) |
9edc5bb8 |
997 | XSRETURN_YES; |
998 | else |
999 | XSRETURN_NO; |
e1a479c5 |
1000 | } |
1001 | |
c5860d66 |
1002 | XS(XS_mro_invalidate_method_caches) |
e1a479c5 |
1003 | { |
1004 | dVAR; |
1005 | dXSARGS; |
1006 | |
1007 | PERL_UNUSED_ARG(cv); |
1008 | |
1009 | if (items != 0) |
1010 | Perl_croak(aTHX_ "Usage: mro::invalidate_all_method_caches()"); |
1011 | |
1012 | PL_sub_generation++; |
1013 | |
1014 | XSRETURN_EMPTY; |
1015 | } |
1016 | |
e1a479c5 |
1017 | XS(XS_mro_method_changed_in) |
1018 | { |
1019 | dVAR; |
1020 | dXSARGS; |
1021 | SV* classname; |
1022 | HV* class_stash; |
1023 | |
1024 | PERL_UNUSED_ARG(cv); |
1025 | |
1026 | if(items != 1) |
1027 | Perl_croak(aTHX_ "Usage: mro::method_changed_in(classname)"); |
1028 | |
1029 | classname = ST(0); |
1030 | |
1031 | class_stash = gv_stashsv(classname, 0); |
1032 | if(!class_stash) Perl_croak(aTHX_ "No such class: '%"SVf"'!", SVfARG(classname)); |
1033 | |
1034 | mro_method_changed_in(class_stash); |
1035 | |
1036 | XSRETURN_EMPTY; |
1037 | } |
1038 | |
1039 | XS(XS_next_can) |
1040 | { |
1041 | dVAR; |
1042 | dXSARGS; |
1e05feb3 |
1043 | SV* const self = ST(0); |
1044 | SV* const methcv = __nextcan(aTHX_ self, 0); |
e1a479c5 |
1045 | |
1046 | PERL_UNUSED_ARG(cv); |
1047 | PERL_UNUSED_VAR(items); |
1048 | |
1049 | if(methcv == &PL_sv_undef) { |
1050 | ST(0) = &PL_sv_undef; |
1051 | } |
1052 | else { |
1053 | ST(0) = sv_2mortal(newRV_inc(methcv)); |
1054 | } |
1055 | |
1056 | XSRETURN(1); |
1057 | } |
1058 | |
1059 | XS(XS_next_method) |
1060 | { |
1061 | dMARK; |
1062 | dAX; |
1e05feb3 |
1063 | SV* const self = ST(0); |
1064 | SV* const methcv = __nextcan(aTHX_ self, 1); |
e1a479c5 |
1065 | |
1066 | PERL_UNUSED_ARG(cv); |
1067 | |
1068 | PL_markstack_ptr++; |
1069 | call_sv(methcv, GIMME_V); |
1070 | } |
1071 | |
1072 | XS(XS_maybe_next_method) |
1073 | { |
1074 | dMARK; |
1075 | dAX; |
1e05feb3 |
1076 | SV* const self = ST(0); |
1077 | SV* const methcv = __nextcan(aTHX_ self, 0); |
e1a479c5 |
1078 | |
1079 | PERL_UNUSED_ARG(cv); |
1080 | |
1081 | if(methcv == &PL_sv_undef) { |
1082 | ST(0) = &PL_sv_undef; |
1083 | XSRETURN(1); |
1084 | } |
1085 | |
1086 | PL_markstack_ptr++; |
1087 | call_sv(methcv, GIMME_V); |
1088 | } |
1089 | |
1090 | /* |
1091 | * Local variables: |
1092 | * c-indentation-style: bsd |
1093 | * c-basic-offset: 4 |
1094 | * indent-tabs-mode: t |
1095 | * End: |
1096 | * |
1097 | * ex: set ts=8 sts=4 sw=4 noet: |
1098 | */ |