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Fix a warning (that spotted a potential mro bug that I could not produce)
[perl5.git] / mro.c
CommitLineData
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1/* mro.c
2 *
3 * Copyright (c) 2007 Brandon L Black
1129b882 4 * Copyright (c) 2007, 2008 Larry Wall and others
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5 *
6 * You may distribute under the terms of either the GNU General Public
7 * License or the Artistic License, as specified in the README file.
8 *
9 */
10
11/*
4ac71550
TC
12 * 'Which order shall we go in?' said Frodo. 'Eldest first, or quickest first?
13 * You'll be last either way, Master Peregrin.'
14 *
15 * [p.101 of _The Lord of the Rings_, I/iii: "A Conspiracy Unmasked"]
cac98860
RGS
16 */
17
18/*
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19=head1 MRO Functions
20
21These functions are related to the method resolution order of perl classes
22
23=cut
24*/
25
26#include "EXTERN.h"
4befac30 27#define PERL_IN_MRO_C
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28#include "perl.h"
29
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30static const struct mro_alg dfs_alg =
31 {S_mro_get_linear_isa_dfs, "dfs", 3, 0, 0};
3d76853f 32
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33SV *
34Perl_mro_get_private_data(pTHX_ struct mro_meta *const smeta,
35 const struct mro_alg *const which)
36{
37 SV **data;
38 PERL_ARGS_ASSERT_MRO_GET_PRIVATE_DATA;
39
5844ac76
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40 data = (SV **)Perl_hv_common(aTHX_ smeta->mro_linear_all, NULL,
41 which->name, which->length, which->kflags,
42 HV_FETCH_JUST_SV, NULL, which->hash);
fa60396f
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43 if (!data)
44 return NULL;
45
46 /* If we've been asked to look up the private data for the current MRO, then
47 cache it. */
48 if (smeta->mro_which == which)
3a6fa573 49 smeta->mro_linear_current = *data;
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50
51 return *data;
52}
53
54SV *
55Perl_mro_set_private_data(pTHX_ struct mro_meta *const smeta,
56 const struct mro_alg *const which, SV *const data)
57{
58 PERL_ARGS_ASSERT_MRO_SET_PRIVATE_DATA;
59
9953ff72 60 if (!smeta->mro_linear_all) {
553e831a
NC
61 if (smeta->mro_which == which) {
62 /* If all we need to store is the current MRO's data, then don't use
63 memory on a hash with 1 element - store it direct, and signal
64 this by leaving the would-be-hash NULL. */
3a6fa573 65 smeta->mro_linear_current = data;
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66 return data;
67 } else {
68 HV *const hv = newHV();
69 /* Start with 2 buckets. It's unlikely we'll need more. */
70 HvMAX(hv) = 1;
9953ff72 71 smeta->mro_linear_all = hv;
553e831a 72
3a6fa573 73 if (smeta->mro_linear_current) {
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74 /* If we were storing something directly, put it in the hash
75 before we lose it. */
76 Perl_mro_set_private_data(aTHX_ smeta, smeta->mro_which,
3a6fa573 77 smeta->mro_linear_current);
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78 }
79 }
80 }
81
82 /* We get here if we're storing more than one linearisation for this stash,
83 or the linearisation we are storing is not that if its current MRO. */
84
85 if (smeta->mro_which == which) {
86 /* If we've been asked to store the private data for the current MRO,
87 then cache it. */
3a6fa573 88 smeta->mro_linear_current = data;
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89 }
90
9953ff72 91 if (!Perl_hv_common(aTHX_ smeta->mro_linear_all, NULL,
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92 which->name, which->length, which->kflags,
93 HV_FETCH_ISSTORE, data, which->hash)) {
94 Perl_croak(aTHX_ "panic: hv_store() failed in set_mro_private_data() "
95 "for '%.*s' %d", (int) which->length, which->name,
96 which->kflags);
97 }
98
99 return data;
100}
101
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102const struct mro_alg *
103Perl_mro_get_from_name(pTHX_ SV *name) {
104 SV **data;
105
106 PERL_ARGS_ASSERT_MRO_GET_FROM_NAME;
107
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108 data = (SV **)Perl_hv_common(aTHX_ PL_registered_mros, name, NULL, 0, 0,
109 HV_FETCH_JUST_SV, NULL, 0);
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110 if (!data)
111 return NULL;
112 assert(SvTYPE(*data) == SVt_IV);
113 assert(SvIOK(*data));
114 return INT2PTR(const struct mro_alg *, SvUVX(*data));
115}
116
117void
118Perl_mro_register(pTHX_ const struct mro_alg *mro) {
119 SV *wrapper = newSVuv(PTR2UV(mro));
120
121 PERL_ARGS_ASSERT_MRO_REGISTER;
122
123
124 if (!Perl_hv_common(aTHX_ PL_registered_mros, NULL,
125 mro->name, mro->length, mro->kflags,
126 HV_FETCH_ISSTORE, wrapper, mro->hash)) {
127 SvREFCNT_dec(wrapper);
128 Perl_croak(aTHX_ "panic: hv_store() failed in mro_register() "
129 "for '%.*s' %d", (int) mro->length, mro->name, mro->kflags);
3d76853f 130 }
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131}
132
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133struct mro_meta*
134Perl_mro_meta_init(pTHX_ HV* stash)
135{
9fe4aecf 136 struct mro_meta* newmeta;
e1a479c5 137
7918f24d 138 PERL_ARGS_ASSERT_MRO_META_INIT;
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139 assert(HvAUX(stash));
140 assert(!(HvAUX(stash)->xhv_mro_meta));
183086be 141 Newxz(newmeta, 1, struct mro_meta);
9fe4aecf 142 HvAUX(stash)->xhv_mro_meta = newmeta;
dd69841b 143 newmeta->cache_gen = 1;
70cd14a1 144 newmeta->pkg_gen = 1;
a3e6e81e 145 newmeta->mro_which = &dfs_alg;
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146
147 return newmeta;
148}
149
150#if defined(USE_ITHREADS)
151
152/* for sv_dup on new threads */
153struct mro_meta*
154Perl_mro_meta_dup(pTHX_ struct mro_meta* smeta, CLONE_PARAMS* param)
155{
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156 struct mro_meta* newmeta;
157
7918f24d 158 PERL_ARGS_ASSERT_MRO_META_DUP;
e1a479c5 159
33e12d9d
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160 Newx(newmeta, 1, struct mro_meta);
161 Copy(smeta, newmeta, 1, struct mro_meta);
162
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163 if (newmeta->mro_linear_all) {
164 newmeta->mro_linear_all
a09252eb 165 = MUTABLE_HV(sv_dup_inc((const SV *)newmeta->mro_linear_all, param));
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166 /* This is just acting as a shortcut pointer, and will be automatically
167 updated on the first get. */
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168 newmeta->mro_linear_current = NULL;
169 } else if (newmeta->mro_linear_current) {
553e831a 170 /* Only the current MRO is stored, so this owns the data. */
3a6fa573 171 newmeta->mro_linear_current
a09252eb 172 = sv_dup_inc((const SV *)newmeta->mro_linear_current, param);
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173 }
174
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175 if (newmeta->mro_nextmethod)
176 newmeta->mro_nextmethod
a09252eb 177 = MUTABLE_HV(sv_dup_inc((const SV *)newmeta->mro_nextmethod, param));
a49ba3fc
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178 if (newmeta->isa)
179 newmeta->isa
a09252eb 180 = MUTABLE_HV(sv_dup_inc((const SV *)newmeta->isa, param));
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181
182 return newmeta;
183}
184
185#endif /* USE_ITHREADS */
186
187/*
188=for apidoc mro_get_linear_isa_dfs
189
190Returns the Depth-First Search linearization of @ISA
191the given stash. The return value is a read-only AV*.
192C<level> should be 0 (it is used internally in this
193function's recursion).
194
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195You are responsible for C<SvREFCNT_inc()> on the
196return value if you plan to store it anywhere
197semi-permanently (otherwise it might be deleted
198out from under you the next time the cache is
199invalidated).
200
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201=cut
202*/
4befac30 203static AV*
94d1e706 204S_mro_get_linear_isa_dfs(pTHX_ HV *stash, U32 level)
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205{
206 AV* retval;
207 GV** gvp;
208 GV* gv;
209 AV* av;
190d0b22 210 const HEK* stashhek;
e1a479c5 211 struct mro_meta* meta;
a49ba3fc 212 SV *our_name;
73519bd0 213 HV *stored = NULL;
e1a479c5 214
7918f24d 215 PERL_ARGS_ASSERT_MRO_GET_LINEAR_ISA_DFS;
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216 assert(HvAUX(stash));
217
00169e2c 218 stashhek
15d9236d 219 = HvAUX(stash)->xhv_name_u.xhvnameu_name && HvENAME_HEK_NN(stash)
00169e2c
FC
220 ? HvENAME_HEK_NN(stash)
221 : HvNAME_HEK(stash);
222
190d0b22 223 if (!stashhek)
1e05feb3 224 Perl_croak(aTHX_ "Can't linearize anonymous symbol table");
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225
226 if (level > 100)
227 Perl_croak(aTHX_ "Recursive inheritance detected in package '%s'",
190d0b22 228 HEK_KEY(stashhek));
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229
230 meta = HvMROMETA(stash);
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231
232 /* return cache if valid */
a3e6e81e 233 if((retval = MUTABLE_AV(MRO_GET_PRIVATE_DATA(meta, &dfs_alg)))) {
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234 return retval;
235 }
236
237 /* not in cache, make a new one */
1c908217 238
ad64d0ec 239 retval = MUTABLE_AV(sv_2mortal(MUTABLE_SV(newAV())));
a49ba3fc
NC
240 /* We use this later in this function, but don't need a reference to it
241 beyond the end of this function, so reference count is fine. */
242 our_name = newSVhek(stashhek);
243 av_push(retval, our_name); /* add ourselves at the top */
e1a479c5 244
1c908217 245 /* fetch our @ISA */
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246 gvp = (GV**)hv_fetchs(stash, "ISA", FALSE);
247 av = (gvp && (gv = *gvp) && isGV_with_GP(gv)) ? GvAV(gv) : NULL;
248
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249 /* "stored" is used to keep track of all of the classnames we have added to
250 the MRO so far, so we can do a quick exists check and avoid adding
251 duplicate classnames to the MRO as we go.
252 It's then retained to be re-used as a fast lookup for ->isa(), by adding
253 our own name and "UNIVERSAL" to it. */
254
a49ba3fc 255 if(av && AvFILLp(av) >= 0) {
1c908217 256
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257 SV **svp = AvARRAY(av);
258 I32 items = AvFILLp(av) + 1;
1c908217
RGS
259
260 /* foreach(@ISA) */
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261 while (items--) {
262 SV* const sv = *svp++;
263 HV* const basestash = gv_stashsv(sv, 0);
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264 SV *const *subrv_p;
265 I32 subrv_items;
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266
267 if (!basestash) {
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268 /* if no stash exists for this @ISA member,
269 simply add it to the MRO and move on */
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270 subrv_p = &sv;
271 subrv_items = 1;
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272 }
273 else {
1c908217 274 /* otherwise, recurse into ourselves for the MRO
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275 of this @ISA member, and append their MRO to ours.
276 The recursive call could throw an exception, which
277 has memory management implications here, hence the use of
278 the mortal. */
ffd8da72
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279 const AV *const subrv
280 = mro_get_linear_isa_dfs(basestash, level + 1);
281
282 subrv_p = AvARRAY(subrv);
283 subrv_items = AvFILLp(subrv) + 1;
284 }
73519bd0
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285 if (stored) {
286 while(subrv_items--) {
287 SV *const subsv = *subrv_p++;
288 /* LVALUE fetch will create a new undefined SV if necessary
289 */
290 HE *const he = hv_fetch_ent(stored, subsv, 1, 0);
291 assert(he);
292 if(HeVAL(he) != &PL_sv_undef) {
293 /* It was newly created. Steal it for our new SV, and
294 replace it in the hash with the "real" thing. */
295 SV *const val = HeVAL(he);
296 HEK *const key = HeKEY_hek(he);
297
298 HeVAL(he) = &PL_sv_undef;
299 /* Save copying by making a shared hash key scalar. We
300 inline this here rather than calling
301 Perl_newSVpvn_share because we already have the
302 scalar, and we already have the hash key. */
303 assert(SvTYPE(val) == SVt_NULL);
304 sv_upgrade(val, SVt_PV);
305 SvPV_set(val, HEK_KEY(share_hek_hek(key)));
306 SvCUR_set(val, HEK_LEN(key));
307 SvREADONLY_on(val);
308 SvFAKE_on(val);
309 SvPOK_on(val);
310 if (HEK_UTF8(key))
311 SvUTF8_on(val);
312
313 av_push(retval, val);
314 }
ffd8da72 315 }
73519bd0
NC
316 } else {
317 /* We are the first (or only) parent. We can short cut the
318 complexity above, because our @ISA is simply us prepended
319 to our parent's @ISA, and our ->isa cache is simply our
320 parent's, with our name added. */
321 /* newSVsv() is slow. This code is only faster if we can avoid
322 it by ensuring that SVs in the arrays are shared hash key
323 scalar SVs, because we can "copy" them very efficiently.
324 Although to be fair, we can't *ensure* this, as a reference
325 to the internal array is returned by mro::get_linear_isa(),
326 so we'll have to be defensive just in case someone faffed
327 with it. */
328 if (basestash) {
329 SV **svp;
17eef65c 330 stored = MUTABLE_HV(sv_2mortal((SV*)newHVhv(HvMROMETA(basestash)->isa)));
73519bd0
NC
331 av_extend(retval, subrv_items);
332 AvFILLp(retval) = subrv_items;
333 svp = AvARRAY(retval);
334 while(subrv_items--) {
335 SV *const val = *subrv_p++;
336 *++svp = SvIsCOW_shared_hash(val)
337 ? newSVhek(SvSHARED_HEK_FROM_PV(SvPVX(val)))
338 : newSVsv(val);
339 }
340 } else {
341 /* They have no stash. So create ourselves an ->isa cache
342 as if we'd copied it from what theirs should be. */
343 stored = MUTABLE_HV(sv_2mortal(MUTABLE_SV(newHV())));
344 (void) hv_store(stored, "UNIVERSAL", 9, &PL_sv_undef, 0);
345 av_push(retval,
346 newSVhek(HeKEY_hek(hv_store_ent(stored, sv,
347 &PL_sv_undef, 0))));
348 }
349 }
e1a479c5 350 }
73519bd0
NC
351 } else {
352 /* We have no parents. */
353 stored = MUTABLE_HV(sv_2mortal(MUTABLE_SV(newHV())));
354 (void) hv_store(stored, "UNIVERSAL", 9, &PL_sv_undef, 0);
e1a479c5
BB
355 }
356
ed09b296 357 (void) hv_store_ent(stored, our_name, &PL_sv_undef, 0);
ed09b296
NC
358
359 SvREFCNT_inc_simple_void_NN(stored);
360 SvTEMP_off(stored);
361 SvREADONLY_on(stored);
362
363 meta->isa = stored;
364
0fd7ece8
NC
365 /* now that we're past the exception dangers, grab our own reference to
366 the AV we're about to use for the result. The reference owned by the
367 mortals' stack will be released soon, so everything will balance. */
368 SvREFCNT_inc_simple_void_NN(retval);
369 SvTEMP_off(retval);
fdef73f9 370
1c908217
RGS
371 /* we don't want anyone modifying the cache entry but us,
372 and we do so by replacing it completely */
e1a479c5 373 SvREADONLY_on(retval);
1c908217 374
a3e6e81e 375 return MUTABLE_AV(Perl_mro_set_private_data(aTHX_ meta, &dfs_alg,
fa60396f 376 MUTABLE_SV(retval)));
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BB
377}
378
379/*
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380=for apidoc mro_get_linear_isa
381
382Returns either C<mro_get_linear_isa_c3> or
383C<mro_get_linear_isa_dfs> for the given stash,
384dependant upon which MRO is in effect
385for that stash. The return value is a
386read-only AV*.
387
1c908217
RGS
388You are responsible for C<SvREFCNT_inc()> on the
389return value if you plan to store it anywhere
390semi-permanently (otherwise it might be deleted
391out from under you the next time the cache is
392invalidated).
393
e1a479c5
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394=cut
395*/
396AV*
397Perl_mro_get_linear_isa(pTHX_ HV *stash)
398{
399 struct mro_meta* meta;
7311f41d 400 AV *isa;
2c7f4b87 401
7918f24d 402 PERL_ARGS_ASSERT_MRO_GET_LINEAR_ISA;
2c7f4b87
BB
403 if(!SvOOK(stash))
404 Perl_croak(aTHX_ "Can't linearize anonymous symbol table");
e1a479c5
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405
406 meta = HvMROMETA(stash);
3d76853f 407 if (!meta->mro_which)
14f97ce6 408 Perl_croak(aTHX_ "panic: invalid MRO!");
7311f41d
FC
409 isa = meta->mro_which->resolve(aTHX_ stash, 0);
410
411 if (!meta->isa) {
412 HV *const isa_hash = newHV();
413 /* Linearisation didn't build it for us, so do it here. */
414 SV *const *svp = AvARRAY(isa);
415 SV *const *const svp_end = svp + AvFILLp(isa) + 1;
416 const HEK *canon_name = HvENAME_HEK(stash);
417 if (!canon_name) canon_name = HvNAME_HEK(stash);
418
419 while (svp < svp_end) {
420 (void) hv_store_ent(isa_hash, *svp++, &PL_sv_undef, 0);
421 }
422
423 (void) hv_common(isa_hash, NULL, HEK_KEY(canon_name),
424 HEK_LEN(canon_name), HEK_FLAGS(canon_name),
425 HV_FETCH_ISSTORE, &PL_sv_undef,
426 HEK_HASH(canon_name));
427 (void) hv_store(isa_hash, "UNIVERSAL", 9, &PL_sv_undef, 0);
428
429 SvREADONLY_on(isa_hash);
430
431 meta->isa = isa_hash;
432 }
433
434 return isa;
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435}
436
437/*
438=for apidoc mro_isa_changed_in
439
1c908217 440Takes the necessary steps (cache invalidations, mostly)
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441when the @ISA of the given package has changed. Invoked
442by the C<setisa> magic, should not need to invoke directly.
443
444=cut
445*/
f7afb547 446
beeda143 447/* Macro to avoid repeating the code five times. */
f7afb547
FC
448#define CLEAR_LINEAR(mEta) \
449 if (mEta->mro_linear_all) { \
450 SvREFCNT_dec(MUTABLE_SV(mEta->mro_linear_all)); \
451 mEta->mro_linear_all = NULL; \
452 /* This is just acting as a shortcut pointer. */ \
453 mEta->mro_linear_current = NULL; \
454 } else if (mEta->mro_linear_current) { \
455 /* Only the current MRO is stored, so this owns the data. */ \
456 SvREFCNT_dec(mEta->mro_linear_current); \
457 mEta->mro_linear_current = NULL; \
458 }
459
e1a479c5 460void
4df35a07 461Perl_mro_isa_changed_in(pTHX_ HV* stash)
e1a479c5
BB
462{
463 dVAR;
464 HV* isarev;
465 AV* linear_mro;
466 HE* iter;
467 SV** svp;
468 I32 items;
1e05feb3 469 bool is_universal;
4df35a07 470 struct mro_meta * meta;
80ebaca2 471 HV *isa = NULL;
e1a479c5 472
4df35a07
FC
473 const char * const stashname = HvENAME_get(stash);
474 const STRLEN stashname_len = HvENAMELEN_get(stash);
475
476 PERL_ARGS_ASSERT_MRO_ISA_CHANGED_IN;
7918f24d 477
2c7f4b87
BB
478 if(!stashname)
479 Perl_croak(aTHX_ "Can't call mro_isa_changed_in() on anonymous symbol table");
480
4df35a07
FC
481
482 /* wipe out the cached linearizations for this stash */
483 meta = HvMROMETA(stash);
f7afb547 484 CLEAR_LINEAR(meta);
4df35a07 485 if (meta->isa) {
80ebaca2
FC
486 /* Steal it for our own purposes. */
487 isa = (HV *)sv_2mortal((SV *)meta->isa);
5782d502 488 meta->isa = NULL;
6f86b615 489 }
70cd14a1 490
4df35a07
FC
491 /* Inc the package generation, since our @ISA changed */
492 meta->pkg_gen++;
493
e1a479c5
BB
494 /* Wipe the global method cache if this package
495 is UNIVERSAL or one of its parents */
dd69841b
BB
496
497 svp = hv_fetch(PL_isarev, stashname, stashname_len, 0);
85fbaab2 498 isarev = svp ? MUTABLE_HV(*svp) : NULL;
dd69841b
BB
499
500 if((stashname_len == 9 && strEQ(stashname, "UNIVERSAL"))
501 || (isarev && hv_exists(isarev, "UNIVERSAL", 9))) {
e1a479c5 502 PL_sub_generation++;
dd69841b
BB
503 is_universal = TRUE;
504 }
1e05feb3 505 else { /* Wipe the local method cache otherwise */
4df35a07 506 meta->cache_gen++;
1e05feb3
AL
507 is_universal = FALSE;
508 }
e1a479c5
BB
509
510 /* wipe next::method cache too */
4df35a07 511 if(meta->mro_nextmethod) hv_clear(meta->mro_nextmethod);
1e05feb3 512
e1a479c5 513 /* Iterate the isarev (classes that are our children),
80ebaca2
FC
514 wiping out their linearization, method and isa caches
515 and upating PL_isarev. */
dd69841b 516 if(isarev) {
80ebaca2
FC
517 HV *isa_hashes = NULL;
518
519 /* We have to iterate through isarev twice to avoid a chicken and
520 * egg problem: if A inherits from B and both are in isarev, A might
521 * be processed before B and use B’s previous linearisation.
522 */
523
524 /* First iteration: Wipe everything, but stash away the isa hashes
525 * since we still need them for updating PL_isarev.
526 */
527
528 if(hv_iterinit(isarev)) {
529 /* Only create the hash if we need it; i.e., if isarev has
530 any elements. */
531 isa_hashes = (HV *)sv_2mortal((SV *)newHV());
532 }
e1a479c5 533 while((iter = hv_iternext(isarev))) {
ec49eb61
NC
534 I32 len;
535 const char* const revkey = hv_iterkey(iter, &len);
536 HV* revstash = gv_stashpvn(revkey, len, 0);
bc2cbbac
BB
537 struct mro_meta* revmeta;
538
539 if(!revstash) continue;
540 revmeta = HvMROMETA(revstash);
f7afb547 541 CLEAR_LINEAR(revmeta);
dd69841b
BB
542 if(!is_universal)
543 revmeta->cache_gen++;
e1a479c5
BB
544 if(revmeta->mro_nextmethod)
545 hv_clear(revmeta->mro_nextmethod);
80ebaca2
FC
546
547 (void)
548 hv_store(
549 isa_hashes, (const char*)&revstash, sizeof(HV *),
550 revmeta->isa ? (SV *)revmeta->isa : &PL_sv_undef, 0
551 );
552 revmeta->isa = NULL;
553 }
554
555 /* Second pass: Update PL_isarev. We can just use isa_hashes to
556 * avoid another round of stash lookups. */
557
558 /* isarev might be deleted from PL_isarev during this loop, so hang
559 * on to it. */
560 SvREFCNT_inc_simple_void_NN(sv_2mortal((SV *)isarev));
561
562 if(isa_hashes) {
563 hv_iterinit(isa_hashes);
564 while((iter = hv_iternext(isa_hashes))) {
565 HV* const revstash = *(HV **)HEK_KEY(HeKEY_hek(iter));
566 HV * const isa = (HV *)HeVAL(iter);
567 const HEK *namehek;
568
80ebaca2
FC
569 /* We're starting at the 2nd element, skipping revstash */
570 linear_mro = mro_get_linear_isa(revstash);
571 svp = AvARRAY(linear_mro) + 1;
572 items = AvFILLp(linear_mro);
573
574 namehek = HvENAME_HEK(revstash);
575 if (!namehek) namehek = HvNAME_HEK(revstash);
576
577 while (items--) {
578 SV* const sv = *svp++;
579 HV* mroisarev;
580
581 HE *he = hv_fetch_ent(PL_isarev, sv, TRUE, 0);
582
583 /* That fetch should not fail. But if it had to create
584 a new SV for us, then will need to upgrade it to an
585 HV (which sv_upgrade() can now do for us). */
586
587 mroisarev = MUTABLE_HV(HeVAL(he));
588
589 SvUPGRADE(MUTABLE_SV(mroisarev), SVt_PVHV);
590
591 /* This hash only ever contains PL_sv_yes. Storing it
592 over itself is almost as cheap as calling hv_exists,
593 so on aggregate we expect to save time by not making
594 two calls to the common HV code for the case where
595 it doesn't exist. */
596
597 (void)
598 hv_store(
599 mroisarev, HEK_KEY(namehek), HEK_LEN(namehek),
600 &PL_sv_yes, 0
601 );
602 }
603
604 if((SV *)isa != &PL_sv_undef)
605 mro_clean_isarev(
606 isa, HEK_KEY(namehek), HEK_LEN(namehek),
607 HvMROMETA(revstash)->isa
608 );
609 }
e1a479c5
BB
610 }
611 }
612
c9143745
FC
613 /* Now iterate our MRO (parents), adding ourselves and everything from
614 our isarev to their isarev.
1c908217
RGS
615 */
616
617 /* We're starting at the 2nd element, skipping ourselves here */
e1a479c5
BB
618 linear_mro = mro_get_linear_isa(stash);
619 svp = AvARRAY(linear_mro) + 1;
620 items = AvFILLp(linear_mro);
1c908217 621
e1a479c5
BB
622 while (items--) {
623 SV* const sv = *svp++;
e1a479c5
BB
624 HV* mroisarev;
625
117b69ca
NC
626 HE *he = hv_fetch_ent(PL_isarev, sv, TRUE, 0);
627
628 /* That fetch should not fail. But if it had to create a new SV for
4ea50411
NC
629 us, then will need to upgrade it to an HV (which sv_upgrade() can
630 now do for us. */
117b69ca 631
85fbaab2 632 mroisarev = MUTABLE_HV(HeVAL(he));
e1a479c5 633
ad64d0ec 634 SvUPGRADE(MUTABLE_SV(mroisarev), SVt_PVHV);
117b69ca 635
25270bc0
NC
636 /* This hash only ever contains PL_sv_yes. Storing it over itself is
637 almost as cheap as calling hv_exists, so on aggregate we expect to
638 save time by not making two calls to the common HV code for the
639 case where it doesn't exist. */
640
04fe65b0 641 (void)hv_store(mroisarev, stashname, stashname_len, &PL_sv_yes, 0);
80ebaca2
FC
642 }
643
80ebaca2
FC
644 /* Delete our name from our former parents’ isarevs. */
645 if(isa && HvARRAY(isa))
646 mro_clean_isarev(isa, stashname, stashname_len, meta->isa);
647}
648
649/* Deletes name from all the isarev entries listed in isa */
650STATIC void
651S_mro_clean_isarev(pTHX_ HV * const isa, const char * const name,
652 const STRLEN len, HV * const exceptions)
653{
654 HE* iter;
e1a479c5 655
80ebaca2
FC
656 PERL_ARGS_ASSERT_MRO_CLEAN_ISAREV;
657
658 /* Delete our name from our former parents’ isarevs. */
659 if(isa && HvARRAY(isa) && hv_iterinit(isa)) {
660 SV **svp;
661 while((iter = hv_iternext(isa))) {
662 I32 klen;
663 const char * const key = hv_iterkey(iter, &klen);
664 if(exceptions && hv_exists(exceptions, key, klen)) continue;
665 svp = hv_fetch(PL_isarev, key, klen, 0);
666 if(svp) {
667 HV * const isarev = (HV *)*svp;
668 (void)hv_delete(isarev, name, len, G_DISCARD);
669 if(!HvARRAY(isarev) || !HvKEYS(isarev))
670 (void)hv_delete(PL_isarev, key, klen, G_DISCARD);
e1a479c5
BB
671 }
672 }
673 }
674}
675
676/*
c8bbf675
FC
677=for apidoc mro_package_moved
678
d056e33c
FC
679Call this function to signal to a stash that it has been assigned to
680another spot in the stash hierarchy. C<stash> is the stash that has been
681assigned. C<oldstash> is the stash it replaces, if any. C<gv> is the glob
afdbe55d 682that is actually being assigned to.
d056e33c 683
35759254 684This can also be called with a null first argument to
d056e33c
FC
685indicate that C<oldstash> has been deleted.
686
687This function invalidates isa caches on the old stash, on all subpackages
688nested inside it, and on the subclasses of all those, including
689non-existent packages that have corresponding entries in C<stash>.
c8bbf675 690
80ebaca2
FC
691It also sets the effective names (C<HvENAME>) on all the stashes as
692appropriate.
693
0290c710 694If the C<gv> is present and is not in the symbol table, then this function
afdbe55d 695simply returns. This checked will be skipped if C<flags & 1>.
0290c710 696
c8bbf675
FC
697=cut
698*/
699void
35759254 700Perl_mro_package_moved(pTHX_ HV * const stash, HV * const oldstash,
afdbe55d 701 const GV * const gv, U32 flags)
c8bbf675 702{
d7879cf0
FC
703 SV *namesv;
704 HEK **namep;
705 I32 name_count;
80ebaca2
FC
706 HV *stashes;
707 HE* iter;
62c1e33f 708
afdbe55d 709 PERL_ARGS_ASSERT_MRO_PACKAGE_MOVED;
35759254 710 assert(stash || oldstash);
35759254 711
d7879cf0 712 /* Determine the name(s) of the location that stash was assigned to
35759254
FC
713 * or from which oldstash was removed.
714 *
928eb066 715 * We cannot reliably use the name in oldstash, because it may have
35759254
FC
716 * been deleted from the location in the symbol table that its name
717 * suggests, as in this case:
718 *
719 * $globref = \*foo::bar::;
720 * Symbol::delete_package("foo");
721 * *$globref = \%baz::;
722 * *$globref = *frelp::;
723 * # calls mro_package_moved(%frelp::, %baz::, *$globref, NULL, 0)
724 *
d7879cf0
FC
725 * So we get it from the gv. But, since the gv may no longer be in the
726 * symbol table, we check that first. The only reliable way to tell is
727 * to see whether its stash has an effective name and whether the gv
728 * resides in that stash under its name. That effective name may be
729 * different from what gv_fullname4 would use.
730 * If flags & 1, the caller has asked us to skip the check.
35759254 731 */
d7879cf0
FC
732 if(!(flags & 1)) {
733 SV **svp;
734 if(
735 !GvSTASH(gv) || !HvENAME(GvSTASH(gv)) ||
736 !(svp = hv_fetch(GvSTASH(gv), GvNAME(gv), GvNAMELEN(gv), 0)) ||
737 *svp != (SV *)gv
738 ) return;
739 }
740 assert(SvOOK(GvSTASH(gv)));
741 assert(GvNAMELEN(gv) > 1);
742 assert(GvNAME(gv)[GvNAMELEN(gv) - 1] == ':');
743 assert(GvNAME(gv)[GvNAMELEN(gv) - 2] == ':');
744 name_count = HvAUX(GvSTASH(gv))->xhv_name_count;
745 if (!name_count) {
746 name_count = 1;
15d9236d 747 namep = &HvAUX(GvSTASH(gv))->xhv_name_u.xhvnameu_name;
d7879cf0
FC
748 }
749 else {
15d9236d 750 namep = HvAUX(GvSTASH(gv))->xhv_name_u.xhvnameu_names;
d7879cf0
FC
751 if (name_count < 0) ++namep, name_count = -name_count - 1;
752 }
753 if (name_count == 1) {
754 if (HEK_LEN(*namep) == 4 && strnEQ(HEK_KEY(*namep), "main", 4)) {
a3179684 755 namesv = newSVpvs_flags("", SVs_TEMP);
d7879cf0
FC
756 }
757 else {
758 namesv = sv_2mortal(newSVhek(*namep));
759 sv_catpvs(namesv, "::");
760 }
761 sv_catpvn(namesv, GvNAME(gv), GvNAMELEN(gv) - 2);
762 /* skip trailing :: */
763 }
764 else {
765 SV *aname;
766 namesv = sv_2mortal((SV *)newAV());
767 while (name_count--) {
768 if(HEK_LEN(*namep) == 4 && strnEQ(HEK_KEY(*namep), "main", 4)){
769 aname = newSVpvs(""); namep++;
770 }
771 else {
772 aname = newSVhek(*namep++);
773 sv_catpvs(aname, "::");
774 }
775 sv_catpvn(aname, GvNAME(gv), GvNAMELEN(gv) - 2);
776 /* skip trailing :: */
777 av_push((AV *)namesv, aname);
778 }
779 }
c8bbf675 780
80ebaca2
FC
781 /* Get a list of all the affected classes. */
782 /* We cannot simply pass them all to mro_isa_changed_in to avoid
783 the list, as that function assumes that only one package has
784 changed. It does not work with:
785
786 @foo::ISA = qw( B B::B );
787 *B:: = delete $::{"A::"};
788
789 as neither B nor B::B can be updated before the other, since they
790 will reset caches on foo, which will see either B or B::B with the
791 wrong name. The names must be set on *all* affected stashes before
beeda143 792 we do anything else. (And linearisations must be cleared, too.)
80ebaca2
FC
793 */
794 stashes = (HV *) sv_2mortal((SV *)newHV());
b89cdb22
FC
795 mro_gather_and_rename(
796 stashes, (HV *) sv_2mortal((SV *)newHV()),
d7879cf0 797 stash, oldstash, namesv
b89cdb22 798 );
80ebaca2 799
80ebaca2
FC
800 /* Once the caches have been wiped on all the classes, call
801 mro_isa_changed_in on each. */
802 hv_iterinit(stashes);
803 while((iter = hv_iternext(stashes))) {
90ba1f34
FC
804 HV * const stash = *(HV **)HEK_KEY(HeKEY_hek(iter));
805 if(HvENAME(stash)) {
806 /* We have to restore the original meta->isa (that
807 mro_gather_and_rename set aside for us) this way, in case
808 one class in this list is a superclass of a another class
809 that we have already encountered. In such a case, meta->isa
810 will have been overwritten without old entries being deleted
811 from PL_isarev. */
812 struct mro_meta * const meta = HvMROMETA(stash);
813 if(meta->isa != (HV *)HeVAL(iter)){
814 SvREFCNT_dec(meta->isa);
815 meta->isa
816 = HeVAL(iter) == &PL_sv_yes
817 ? NULL
818 : (HV *)HeVAL(iter);
819 HeVAL(iter) = NULL; /* We donated our reference count. */
820 }
821 mro_isa_changed_in(stash);
822 }
80ebaca2
FC
823 }
824}
825
826void
b89cdb22 827S_mro_gather_and_rename(pTHX_ HV * const stashes, HV * const seen_stashes,
d7879cf0 828 HV *stash, HV *oldstash, SV *namesv)
80ebaca2
FC
829{
830 register XPVHV* xhv;
831 register HE *entry;
832 I32 riter = -1;
d7879cf0 833 I32 items;
80ebaca2 834 const bool stash_had_name = stash && HvENAME(stash);
d7879cf0 835 bool fetched_isarev = FALSE;
80ebaca2
FC
836 HV *seen = NULL;
837 HV *isarev = NULL;
d7879cf0 838 SV **svp = NULL;
80ebaca2
FC
839
840 PERL_ARGS_ASSERT_MRO_GATHER_AND_RENAME;
841
b89cdb22
FC
842 /* We use the seen_stashes hash to keep track of which packages have
843 been encountered so far. This must be separate from the main list of
844 stashes, as we need to distinguish between stashes being assigned
845 and stashes being replaced/deleted. (A nested stash can be on both
846 sides of an assignment. We cannot simply skip iterating through a
847 stash on the right if we have seen it on the left, as it will not
848 get its ename assigned to it.)
849
850 To avoid allocating extra SVs, instead of a bitfield we can make
851 bizarre use of immortals:
852
853 &PL_sv_undef: seen on the left (oldstash)
854 &PL_sv_no : seen on the right (stash)
855 &PL_sv_yes : seen on both sides
856
857 */
858
80ebaca2
FC
859 if(oldstash) {
860 /* Add to the big list. */
90ba1f34 861 struct mro_meta * meta;
80ebaca2
FC
862 HE * const entry
863 = (HE *)
864 hv_common(
b89cdb22 865 seen_stashes, NULL, (const char *)&oldstash, sizeof(HV *), 0,
df5f182b 866 HV_FETCH_LVALUE|HV_FETCH_EMPTY_HE, NULL, 0
80ebaca2 867 );
b89cdb22 868 if(HeVAL(entry) == &PL_sv_undef || HeVAL(entry) == &PL_sv_yes) {
80ebaca2
FC
869 oldstash = NULL;
870 goto check_stash;
871 }
b89cdb22
FC
872 HeVAL(entry)
873 = HeVAL(entry) == &PL_sv_no ? &PL_sv_yes : &PL_sv_undef;
90ba1f34 874 meta = HvMROMETA(oldstash);
b89cdb22
FC
875 (void)
876 hv_store(
877 stashes, (const char *)&oldstash, sizeof(HV *),
90ba1f34
FC
878 meta->isa
879 ? SvREFCNT_inc_simple_NN((SV *)meta->isa)
880 : &PL_sv_yes,
881 0
b89cdb22 882 );
beeda143 883 CLEAR_LINEAR(meta);
80ebaca2
FC
884
885 /* Update the effective name. */
886 if(HvENAME_get(oldstash)) {
d7879cf0
FC
887 const HEK * const enamehek = HvENAME_HEK(oldstash);
888 if(SvTYPE(namesv) == SVt_PVAV) {
889 items = AvFILLp((AV *)namesv) + 1;
890 svp = AvARRAY((AV *)namesv);
891 }
892 else {
893 items = 1;
894 svp = &namesv;
895 }
896 while (items--) {
897 STRLEN len;
898 const char *name = SvPVx_const(*svp++, len);
899 if(PL_stashcache)
900 (void)hv_delete(PL_stashcache, name, len, G_DISCARD);
901 hv_ename_delete(oldstash, name, len, 0);
902
903 if (!fetched_isarev) {
904 /* If the name deletion caused a name change, then we
905 * are not going to call mro_isa_changed_in with this
906 * name (and not at all if it has become anonymous) so
907 * we need to delete old isarev entries here, both
908 * those in the superclasses and this class’s own list
909 * of subclasses. We simply delete the latter from
910 * PL_isarev, since we still need it. hv_delete morti-
911 * fies it for us, so sv_2mortal is not necessary. */
912 if(HvENAME_HEK(oldstash) != enamehek) {
913 if(meta->isa && HvARRAY(meta->isa))
914 mro_clean_isarev(meta->isa, name, len, NULL);
915 isarev = (HV *)hv_delete(PL_isarev, name, len, 0);
916 fetched_isarev=TRUE;
917 }
918 }
919 }
80ebaca2 920 }
d7fbb1de 921 }
80ebaca2 922 check_stash:
8b9e80a3 923 if(stash) {
d7879cf0
FC
924 if(SvTYPE(namesv) == SVt_PVAV) {
925 items = AvFILLp((AV *)namesv) + 1;
926 svp = AvARRAY((AV *)namesv);
927 }
928 else {
929 items = 1;
930 svp = &namesv;
931 }
932 while (items--) {
933 STRLEN len;
934 const char *name = SvPVx_const(*svp++, len);
935 hv_ename_add(stash, name, len, 0);
936 }
80ebaca2 937
b89cdb22
FC
938 /* Add it to the big list if it needs
939 * mro_isa_changed_in called on it. That happens if it was
80ebaca2
FC
940 * detached from the symbol table (so it had no HvENAME) before
941 * being assigned to the spot named by the ‘name’ variable, because
942 * its cached isa linerisation is now stale (the effective name
943 * having changed), and subclasses will then use that cache when
944 * mro_package_moved calls mro_isa_changed_in. (See
8b9e80a3 945 * [perl #77358].)
80ebaca2 946 *
8b9e80a3 947 * If it did have a name, then its previous name is still
80ebaca2
FC
948 * used in isa caches, and there is no need for
949 * mro_package_moved to call mro_isa_changed_in.
8b9e80a3 950 */
80ebaca2
FC
951
952 entry
953 = (HE *)
954 hv_common(
b89cdb22 955 seen_stashes, NULL, (const char *)&stash, sizeof(HV *), 0,
df5f182b 956 HV_FETCH_LVALUE|HV_FETCH_EMPTY_HE, NULL, 0
80ebaca2 957 );
b89cdb22 958 if(HeVAL(entry) == &PL_sv_yes || HeVAL(entry) == &PL_sv_no)
80ebaca2 959 stash = NULL;
b89cdb22
FC
960 else {
961 HeVAL(entry)
962 = HeVAL(entry) == &PL_sv_undef ? &PL_sv_yes : &PL_sv_no;
963 if(!stash_had_name)
90ba1f34
FC
964 {
965 struct mro_meta * const meta = HvMROMETA(stash);
b89cdb22
FC
966 (void)
967 hv_store(
968 stashes, (const char *)&stash, sizeof(HV *),
90ba1f34
FC
969 meta->isa
970 ? SvREFCNT_inc_simple_NN((SV *)meta->isa)
971 : &PL_sv_yes,
972 0
b89cdb22 973 );
beeda143 974 CLEAR_LINEAR(meta);
90ba1f34 975 }
b89cdb22 976 }
8b9e80a3 977 }
d7fbb1de 978
80ebaca2
FC
979 if(!stash && !oldstash)
980 /* Both stashes have been encountered already. */
981 return;
982
983 /* Add all the subclasses to the big list. */
d7879cf0
FC
984 if(!fetched_isarev) {
985 /* If oldstash is not null, then we can use its HvENAME to look up
986 the isarev hash, since all its subclasses will be listed there.
987
a51ee39b
RGS
988 If oldstash is null or is no longer in the symbol table, then
989 this is an empty spot with no stash in it, so subclasses could
990 be listed in isarev hashes belonging to any of the names, so we
991 have to check all of them. */
992 char *hvename = oldstash ? HvENAME(oldstash) : NULL;
993 if (hvename) {
d7879cf0 994 fetched_isarev = TRUE;
a51ee39b 995 svp = hv_fetch(PL_isarev, hvename, HvENAMELEN_get(oldstash), 0);
d7879cf0
FC
996 if (svp) isarev = MUTABLE_HV(*svp);
997 }
998 else if(SvTYPE(namesv) == SVt_PVAV) {
999 items = AvFILLp((AV *)namesv) + 1;
1000 svp = AvARRAY((AV *)namesv);
1001 }
1002 else {
1003 items = 1;
1004 svp = &namesv;
1005 }
1006 }
80ebaca2 1007 if(
d7879cf0 1008 isarev || !fetched_isarev
80ebaca2 1009 ) {
d7879cf0 1010 while (fetched_isarev || items--) {
80ebaca2 1011 HE *iter;
d7879cf0
FC
1012
1013 if (!fetched_isarev) {
1014 HE * const he = hv_fetch_ent(PL_isarev, *svp++, 0, 0);
1015 if (!he || !(isarev = MUTABLE_HV(HeVAL(he)))) continue;
1016 }
1017
80ebaca2
FC
1018 hv_iterinit(isarev);
1019 while((iter = hv_iternext(isarev))) {
1020 I32 len;
1021 const char* const revkey = hv_iterkey(iter, &len);
1022 HV* revstash = gv_stashpvn(revkey, len, 0);
90ba1f34 1023 struct mro_meta * meta;
80ebaca2
FC
1024
1025 if(!revstash) continue;
90ba1f34 1026 meta = HvMROMETA(revstash);
b89cdb22
FC
1027 (void)
1028 hv_store(
1029 stashes, (const char *)&revstash, sizeof(HV *),
90ba1f34
FC
1030 meta->isa
1031 ? SvREFCNT_inc_simple_NN((SV *)meta->isa)
1032 : &PL_sv_yes,
1033 0
b89cdb22 1034 );
beeda143 1035 CLEAR_LINEAR(meta);
80ebaca2 1036 }
d7879cf0
FC
1037
1038 if (fetched_isarev) break;
1039 }
80ebaca2 1040 }
d056e33c 1041
c8bbf675
FC
1042 /* This is partly based on code in hv_iternext_flags. We are not call-
1043 ing that here, as we want to avoid resetting the hash iterator. */
1044
d056e33c
FC
1045 /* Skip the entire loop if the hash is empty. */
1046 if(oldstash && HvUSEDKEYS(oldstash)) {
1047 xhv = (XPVHV*)SvANY(oldstash);
dbe2fffc 1048 seen = (HV *) sv_2mortal((SV *)newHV());
d056e33c 1049
80ebaca2
FC
1050 /* Iterate through entries in the oldstash, adding them to the
1051 list, meanwhile doing the equivalent of $seen{$key} = 1.
d056e33c
FC
1052 */
1053
1054 while (++riter <= (I32)xhv->xhv_max) {
1055 entry = (HvARRAY(oldstash))[riter];
1056
1057 /* Iterate through the entries in this list */
1058 for(; entry; entry = HeNEXT(entry)) {
1059 const char* key;
1060 I32 len;
1061
1062 /* If this entry is not a glob, ignore it.
1063 Try the next. */
1064 if (!isGV(HeVAL(entry))) continue;
1065
1066 key = hv_iterkey(entry, &len);
1067 if(len > 1 && key[len-2] == ':' && key[len-1] == ':') {
1068 HV * const oldsubstash = GvHV(HeVAL(entry));
1069 SV ** const stashentry
1070 = stash ? hv_fetch(stash, key, len, 0) : NULL;
35759254 1071 HV *substash = NULL;
62c1e33f
FC
1072
1073 /* Avoid main::main::main::... */
1074 if(oldsubstash == oldstash) continue;
1075
d056e33c 1076 if(
35759254
FC
1077 (
1078 stashentry && *stashentry
1079 && (substash = GvHV(*stashentry))
1080 )
00169e2c 1081 || (oldsubstash && HvENAME_get(oldsubstash))
d056e33c 1082 )
35759254
FC
1083 {
1084 /* Add :: and the key (minus the trailing ::)
d7879cf0
FC
1085 to each name. */
1086 SV *subname;
1087 if(SvTYPE(namesv) == SVt_PVAV) {
1088 SV *aname;
1089 items = AvFILLp((AV *)namesv) + 1;
1090 svp = AvARRAY((AV *)namesv);
1091 subname = sv_2mortal((SV *)newAV());
1092 while (items--) {
1093 aname = newSVsv(*svp++);
1094 sv_catpvs(aname, "::");
1095 sv_catpvn(aname, key, len-2);
1096 av_push((AV *)subname, aname);
1097 }
80ebaca2 1098 }
d7879cf0
FC
1099 else {
1100 subname = sv_2mortal(newSVsv(namesv));
1101 sv_catpvs(subname, "::");
1102 sv_catpvn(subname, key, len-2);
1103 }
1104 mro_gather_and_rename(
1105 stashes, seen_stashes,
1106 substash, oldsubstash, subname
1107 );
35759254 1108 }
d056e33c
FC
1109
1110 (void)hv_store(seen, key, len, &PL_sv_yes, 0);
1111 }
1112 }
1113 }
1114 }
c8bbf675
FC
1115
1116 /* Skip the entire loop if the hash is empty. */
d056e33c
FC
1117 if (stash && HvUSEDKEYS(stash)) {
1118 xhv = (XPVHV*)SvANY(stash);
b89cdb22 1119 riter = -1;
d056e33c
FC
1120
1121 /* Iterate through the new stash, skipping $seen{$key} items,
b89cdb22 1122 calling mro_gather_and_rename(stashes,seen,entry,NULL, ...). */
c8bbf675
FC
1123 while (++riter <= (I32)xhv->xhv_max) {
1124 entry = (HvARRAY(stash))[riter];
1125
1126 /* Iterate through the entries in this list */
1127 for(; entry; entry = HeNEXT(entry)) {
1128 const char* key;
1129 I32 len;
1130
1131 /* If this entry is not a glob, ignore it.
1132 Try the next. */
1133 if (!isGV(HeVAL(entry))) continue;
1134
1135 key = hv_iterkey(entry, &len);
1136 if(len > 1 && key[len-2] == ':' && key[len-1] == ':') {
d056e33c
FC
1137 HV *substash;
1138
1139 /* If this entry was seen when we iterated through the
1140 oldstash, skip it. */
1141 if(seen && hv_exists(seen, key, len)) continue;
1142
1143 /* We get here only if this stash has no corresponding
1144 entry in the stash being replaced. */
1145
1146 substash = GvHV(HeVAL(entry));
35759254 1147 if(substash) {
d7879cf0 1148 SV *subname;
62c1e33f
FC
1149
1150 /* Avoid checking main::main::main::... */
1151 if(substash == stash) continue;
1152
d056e33c 1153 /* Add :: and the key (minus the trailing ::)
d7879cf0
FC
1154 to each name. */
1155 if(SvTYPE(namesv) == SVt_PVAV) {
1156 SV *aname;
1157 items = AvFILLp((AV *)namesv) + 1;
1158 svp = AvARRAY((AV *)namesv);
1159 subname = sv_2mortal((SV *)newAV());
1160 while (items--) {
1161 aname = newSVsv(*svp++);
1162 sv_catpvs(aname, "::");
1163 sv_catpvn(aname, key, len-2);
1164 av_push((AV *)subname, aname);
1165 }
1166 }
1167 else {
1168 subname = sv_2mortal(newSVsv(namesv));
1169 sv_catpvs(subname, "::");
1170 sv_catpvn(subname, key, len-2);
1171 }
80ebaca2 1172 mro_gather_and_rename(
b89cdb22 1173 stashes, seen_stashes,
d7879cf0 1174 substash, NULL, subname
d056e33c
FC
1175 );
1176 }
c8bbf675
FC
1177 }
1178 }
1179 }
1180 }
1181}
1182
1183/*
e1a479c5
BB
1184=for apidoc mro_method_changed_in
1185
47c9dd14
BB
1186Invalidates method caching on any child classes
1187of the given stash, so that they might notice
1188the changes in this one.
e1a479c5
BB
1189
1190Ideally, all instances of C<PL_sub_generation++> in
dd69841b
BB
1191perl source outside of C<mro.c> should be
1192replaced by calls to this.
1193
1194Perl automatically handles most of the common
1195ways a method might be redefined. However, there
1196are a few ways you could change a method in a stash
1197without the cache code noticing, in which case you
1198need to call this method afterwards:
e1a479c5 1199
dd69841b
BB
12001) Directly manipulating the stash HV entries from
1201XS code.
e1a479c5 1202
dd69841b
BB
12032) Assigning a reference to a readonly scalar
1204constant into a stash entry in order to create
1205a constant subroutine (like constant.pm
1206does).
1207
1208This same method is available from pure perl
1209via, C<mro::method_changed_in(classname)>.
e1a479c5
BB
1210
1211=cut
1212*/
1213void
1214Perl_mro_method_changed_in(pTHX_ HV *stash)
1215{
00169e2c
FC
1216 const char * const stashname = HvENAME_get(stash);
1217 const STRLEN stashname_len = HvENAMELEN_get(stash);
dd69841b 1218
1e05feb3 1219 SV ** const svp = hv_fetch(PL_isarev, stashname, stashname_len, 0);
85fbaab2 1220 HV * const isarev = svp ? MUTABLE_HV(*svp) : NULL;
e1a479c5 1221
7918f24d
NC
1222 PERL_ARGS_ASSERT_MRO_METHOD_CHANGED_IN;
1223
2c7f4b87
BB
1224 if(!stashname)
1225 Perl_croak(aTHX_ "Can't call mro_method_changed_in() on anonymous symbol table");
1226
70cd14a1
CB
1227 /* Inc the package generation, since a local method changed */
1228 HvMROMETA(stash)->pkg_gen++;
1229
e1a479c5
BB
1230 /* If stash is UNIVERSAL, or one of UNIVERSAL's parents,
1231 invalidate all method caches globally */
dd69841b
BB
1232 if((stashname_len == 9 && strEQ(stashname, "UNIVERSAL"))
1233 || (isarev && hv_exists(isarev, "UNIVERSAL", 9))) {
e1a479c5
BB
1234 PL_sub_generation++;
1235 return;
1236 }
1237
1238 /* else, invalidate the method caches of all child classes,
1239 but not itself */
dd69841b 1240 if(isarev) {
1e05feb3
AL
1241 HE* iter;
1242
e1a479c5
BB
1243 hv_iterinit(isarev);
1244 while((iter = hv_iternext(isarev))) {
ec49eb61
NC
1245 I32 len;
1246 const char* const revkey = hv_iterkey(iter, &len);
1247 HV* const revstash = gv_stashpvn(revkey, len, 0);
bc2cbbac
BB
1248 struct mro_meta* mrometa;
1249
1250 if(!revstash) continue;
1251 mrometa = HvMROMETA(revstash);
dd69841b 1252 mrometa->cache_gen++;
e1a479c5
BB
1253 if(mrometa->mro_nextmethod)
1254 hv_clear(mrometa->mro_nextmethod);
1255 }
1256 }
1257}
1258
31b9005d
NC
1259void
1260Perl_mro_set_mro(pTHX_ struct mro_meta *const meta, SV *const name)
1261{
1262 const struct mro_alg *const which = Perl_mro_get_from_name(aTHX_ name);
1263
1264 PERL_ARGS_ASSERT_MRO_SET_MRO;
1265
1266 if (!which)
1267 Perl_croak(aTHX_ "Invalid mro name: '%"SVf"'", name);
1268
1269 if(meta->mro_which != which) {
9953ff72 1270 if (meta->mro_linear_current && !meta->mro_linear_all) {
31b9005d
NC
1271 /* If we were storing something directly, put it in the hash before
1272 we lose it. */
1273 Perl_mro_set_private_data(aTHX_ meta, meta->mro_which,
3a6fa573 1274 MUTABLE_SV(meta->mro_linear_current));
31b9005d
NC
1275 }
1276 meta->mro_which = which;
1277 /* Scrub our cached pointer to the private data. */
3a6fa573 1278 meta->mro_linear_current = NULL;
31b9005d
NC
1279 /* Only affects local method cache, not
1280 even child classes */
1281 meta->cache_gen++;
1282 if(meta->mro_nextmethod)
1283 hv_clear(meta->mro_nextmethod);
1284 }
1285}
1286
e1a479c5
BB
1287#include "XSUB.h"
1288
e1a479c5 1289XS(XS_mro_method_changed_in);
e1a479c5
BB
1290
1291void
1292Perl_boot_core_mro(pTHX)
1293{
1294 dVAR;
1295 static const char file[] = __FILE__;
1296
a3e6e81e 1297 Perl_mro_register(aTHX_ &dfs_alg);
a3e6e81e 1298
e1a479c5 1299 newXSproto("mro::method_changed_in", XS_mro_method_changed_in, file, "$");
e1a479c5
BB
1300}
1301
e1a479c5
BB
1302XS(XS_mro_method_changed_in)
1303{
1304 dVAR;
1305 dXSARGS;
1306 SV* classname;
1307 HV* class_stash;
1308
e1a479c5 1309 if(items != 1)
afa74d42 1310 croak_xs_usage(cv, "classname");
e1a479c5
BB
1311
1312 classname = ST(0);
1313
1314 class_stash = gv_stashsv(classname, 0);
1315 if(!class_stash) Perl_croak(aTHX_ "No such class: '%"SVf"'!", SVfARG(classname));
1316
1317 mro_method_changed_in(class_stash);
1318
1319 XSRETURN_EMPTY;
1320}
1321
e1a479c5
BB
1322/*
1323 * Local variables:
1324 * c-indentation-style: bsd
1325 * c-basic-offset: 4
1326 * indent-tabs-mode: t
1327 * End:
1328 *
1329 * ex: set ts=8 sts=4 sw=4 noet:
1330 */