lib/Class/C3/XS.xs

   1
   2 #include "EXTERN.h"
   3 #include "perl.h"
   4 #include "XSUB.h"
   5
   6 /* Most of this code is backported from the bleadperl patch's
   7    mro.c, and then modified to work with Class::C3's
   8    internals.
   9 */
  10
  11 AV*
  12 __mro_linear_isa_c3(pTHX_ HV* stash, HV* cache, I32 level)
  13 {
  14     AV* retval;
  15     GV** gvp;
  16     GV* gv;
  17     AV* isa;
  18     const char* stashname;
  19     STRLEN stashname_len;
  20
  21     assert(stash);
  22     assert(HvAUX(stash));
  23
  24     stashname = HvNAME(stash);
  25     stashname_len = strlen(stashname);
  26     if (!stashname)
  27       Perl_croak(aTHX_
  28                  "Can't linearize anonymous symbol table");
  29
  30     if (level > 100)
  31         Perl_croak(aTHX_ "Recursive inheritance detected in package '%s'",
  32               stashname);
  33
  34     if(!cache) {
  35         cache = sv_2mortal(newHV());
  36     }
  37     else {
  38 /*
  39         SV** cache_entry = hv_fetch(cache, stashname, stashname_len, 0);
  40         if(cache_entry)
  41             return (AV*)SvREFCNT_inc(*cache_entry);
  42 */
  43     }
  44
  45     /* not in cache, make a new one */
  46
  47     retval = (AV*)sv_2mortal((SV*)newAV());
  48     av_push(retval, newSVpvn(stashname, stashname_len)); /* us first */
  49
  50     gvp = (GV**)hv_fetch(stash, "ISA", 3, FALSE);
  51     isa = (gvp && (gv = *gvp) && gv != (GV*)&PL_sv_undef) ? GvAV(gv) : NULL;
  52
  53     if(isa && AvFILLp(isa) >= 0) {
  54         SV** seqs_ptr;
  55         I32 seqs_items;
  56         HV* tails = (HV*)sv_2mortal((SV*)newHV());
  57         AV* seqs = (AV*)sv_2mortal((SV*)newAV());
  58         I32 items = AvFILLp(isa) + 1;
  59         SV** isa_ptr = AvARRAY(isa);
  60         while(items--) {
  61             AV* isa_lin;
  62             SV* isa_item = *isa_ptr++;
  63             HV* isa_item_stash = gv_stashsv(isa_item, 0);
  64             if(!isa_item_stash) {
  65                 isa_lin = newAV();
  66                 av_push(isa_lin, newSVsv(isa_item));
  67             }
  68             else {
  69                 isa_lin = (AV*)sv_2mortal((SV*)__mro_linear_isa_c3(isa_item_stash, cache, level + 1)); /* recursion */
  70             }
  71             av_push(seqs, (SV*)av_make(AvFILLp(isa_lin)+1, AvARRAY(isa_lin)));
  72         }
  73         av_push(seqs, (SV*)av_make(AvFILLp(isa)+1, AvARRAY(isa)));
  74
  75         seqs_ptr = AvARRAY(seqs);
  76         seqs_items = AvFILLp(seqs) + 1;
  77         while(seqs_items--) {
  78             AV* seq = (AV*)*seqs_ptr++;
  79             I32 seq_items = AvFILLp(seq);
  80             if(seq_items > 0) {
  81                 SV** seq_ptr = AvARRAY(seq) + 1;
  82                 while(seq_items--) {
  83                     SV* seqitem = *seq_ptr++;
  84                     HE* he = hv_fetch_ent(tails, seqitem, 0, 0);
  85                     if(!he) {
  86                         hv_store_ent(tails, seqitem, newSViv(1), 0);
  87                     }
  88                     else {
  89                         SV* val = HeVAL(he);
  90                         sv_inc(val);
  91                     }
  92                 }
  93             }
  94         }
  95
  96         while(1) {
  97             SV* seqhead = NULL;
  98             SV* cand = NULL;
  99             SV* winner = NULL;
 100             SV* val;
 101             HE* tail_entry;
 102             AV* seq;
 103             SV** avptr = AvARRAY(seqs);
 104             items = AvFILLp(seqs)+1;
 105             while(items--) {
 106                 SV** svp;
 107                 seq = (AV*)*avptr++;
 108                 if(AvFILLp(seq) < 0) continue;
 109                 svp = av_fetch(seq, 0, 0);
 110                 seqhead = *svp;
 111                 if(!winner) {
 112                     cand = seqhead;
 113                     if((tail_entry = hv_fetch_ent(tails, cand, 0, 0))
 114                        && (val = HeVAL(tail_entry))
 115                        && (SvIVx(val) > 0))
 116                            continue;
 117                     winner = newSVsv(cand);
 118                     av_push(retval, winner);
 119                 }
 120                 if(!sv_cmp(seqhead, winner)) {
 121
 122                     /* this is basically shift(@seq) in void context */
 123                     SvREFCNT_dec(*AvARRAY(seq));
 124                     *AvARRAY(seq) = &PL_sv_undef;
 125                     AvARRAY(seq) = AvARRAY(seq) + 1;
 126                     AvMAX(seq)--;
 127                     AvFILLp(seq)--;
 128
 129                     if(AvFILLp(seq) < 0) continue;
 130                     svp = av_fetch(seq, 0, 0);
 131                     seqhead = *svp;
 132                     tail_entry = hv_fetch_ent(tails, seqhead, 0, 0);
 133                     val = HeVAL(tail_entry);
 134                     sv_dec(val);
 135                 }
 136             }
 137             if(!cand) break;
 138             if(!winner)
 139                 Perl_croak(aTHX_ "Inconsistent hierarchy during C3 merge of class '%s': "
 140                     "merging failed on parent '%s'", stashname, SvPV_nolen(cand));
 141         }
 142     }
 143
 144     SvREADONLY_on(retval);
 145     SvREFCNT_inc(retval); /* for cache storage */
 146     SvREFCNT_inc(retval); /* for return */
 147     /* hv_store(cache, stashname, stashname_len, (SV*)retval, 0); */
 148     return retval;
 149 }
 150
 151 STATIC I32
 152 __dopoptosub_at(const PERL_CONTEXT *cxstk, I32 startingblock) {
 153     I32 i;
 154     for (i = startingblock; i >= 0; i--) {
 155         if(CxTYPE((PERL_CONTEXT*)(&cxstk[i])) == CXt_SUB) return i;
 156     }
 157     return i;
 158 }
 159
 160 STATIC SV*
 161 __nextcan(pTHX_ SV* self, I32 throw_nomethod)
 162 {
 163     register I32 cxix;
 164     register const PERL_CONTEXT *ccstack = cxstack;
 165     const PERL_SI *top_si = PL_curstackinfo;
 166     HV* selfstash;
 167     GV* cvgv;
 168     SV *stashname;
 169     const char *fq_subname;
 170     const char *subname;
 171     STRLEN fq_subname_len;
 172     STRLEN stashname_len;
 173     STRLEN subname_len;
 174     SV* sv;
 175     GV** gvp;
 176     AV* linear_av;
 177     SV** linear_svp;
 178     SV* linear_sv;
 179     HV* cstash;
 180     GV* candidate = NULL;
 181     CV* cand_cv = NULL;
 182     const char *hvname;
 183     I32 items;
 184     struct mro_meta* selfmeta;
 185     HV* nmcache;
 186     HE* cache_entry;
 187
 188     if(sv_isobject(self))
 189         selfstash = SvSTASH(SvRV(self));
 190     else
 191         selfstash = gv_stashsv(self, 0);
 192
 193     assert(selfstash);
 194
 195     hvname = HvNAME(selfstash);
 196     if (!hvname)
 197         croak("Can't use anonymous symbol table for method lookup");
 198
 199     cxix = __dopoptosub_at(cxstack, cxstack_ix);
 200
 201     /* This block finds the contextually-enclosing fully-qualified subname,
 202        much like looking at (caller($i))[3] until you find a real sub that
 203        isn't ANON, etc */
 204     for (;;) {
 205         /* we may be in a higher stacklevel, so dig down deeper */
 206         while (cxix < 0) {
 207             if(top_si->si_type == PERLSI_MAIN)
 208                 croak("next::method/next::can/maybe::next::method must be used in method context");
 209             top_si = top_si->si_prev;
 210             ccstack = top_si->si_cxstack;
 211             cxix = __dopoptosub_at(ccstack, top_si->si_cxix);
 212         }
 213
 214         if(CxTYPE((PERL_CONTEXT*)(&ccstack[cxix])) != CXt_SUB
 215           || (PL_DBsub && GvCV(PL_DBsub) && ccstack[cxix].blk_sub.cv == GvCV(PL_DBsub))) {
 216             cxix = __dopoptosub_at(ccstack, cxix - 1);
 217             continue;
 218         }
 219
 220         {
 221             const I32 dbcxix = __dopoptosub_at(ccstack, cxix - 1);
 222             if (PL_DBsub && GvCV(PL_DBsub) && dbcxix >= 0 && ccstack[dbcxix].blk_sub.cv == GvCV(PL_DBsub)) {
 223                 if(CxTYPE((PERL_CONTEXT*)(&ccstack[dbcxix])) != CXt_SUB) {
 224                     cxix = dbcxix;
 225                     continue;
 226                 }
 227             }
 228         }
 229
 230         cvgv = CvGV(ccstack[cxix].blk_sub.cv);
 231
 232         if(!isGV(cvgv)) {
 233             cxix = __dopoptosub_at(ccstack, cxix - 1);
 234             continue;
 235         }
 236
 237         /* we found a real sub here */
 238         sv = sv_2mortal(newSV(0));
 239
 240         gv_efullname3(sv, cvgv, NULL);
 241
 242         fq_subname = SvPVX(sv);
 243         fq_subname_len = SvCUR(sv);
 244
 245         subname = strrchr(fq_subname, ':');
 246         if(!subname)
 247             croak("next::method/next::can/maybe::next::method cannot find enclosing method");
 248
 249         subname++;
 250         subname_len = fq_subname_len - (subname - fq_subname);
 251         if(subname_len == 8 && strEQ(subname, "__ANON__")) {
 252             cxix = __dopoptosub_at(ccstack, cxix - 1);
 253             continue;
 254         }
 255         break;
 256     }
 257
 258     /* If we made it to here, we found our context */
 259
 260     /*
 261     XXX check %next::METHOD_CACHE
 262
 263     selfmeta = HvMROMETA(selfstash);
 264     if(!(nmcache = selfmeta->mro_nextmethod)) {
 265         nmcache = selfmeta->mro_nextmethod = newHV();
 266     }
 267
 268     if((cache_entry = hv_fetch_ent(nmcache, sv, 0, 0))) {
 269         SV* val = HeVAL(cache_entry);
 270         if(val == &PL_sv_undef) {
 271             if(throw_nomethod)
 272                 croak("No next::method '%s' found for %s", subname, hvname);
 273             return &PL_sv_undef;
 274         }
 275         return SvREFCNT_inc(val);
 276     }
 277     */
 278
 279     /* beyond here is just for cache misses, so perf isn't as critical */
 280
 281     stashname_len = subname - fq_subname - 2;
 282     stashname = sv_2mortal(newSVpvn(fq_subname, stashname_len));
 283
 284     linear_av = (AV*)sv_2mortal((SV*)__mro_linear_isa_c3(selfstash, NULL, 0));
 285
 286     linear_svp = AvARRAY(linear_av);
 287     items = AvFILLp(linear_av) + 1;
 288
 289     while (items--) {
 290         linear_sv = *linear_svp++;
 291         assert(linear_sv);
 292         if(sv_eq(linear_sv, stashname))
 293             break;
 294     }
 295
 296     if(items > 0) {
 297         SV* sub_sv = sv_2mortal(newSVpv(subname, subname_len));
 298         HV* cc3_mro = get_hv("Class::C3::MRO", 0);
 299
 300         while (items--) {
 301             linear_sv = *linear_svp++;
 302             assert(linear_sv);
 303
 304             if(cc3_mro) {
 305                 HE* he_cc3_mro_class = hv_fetch_ent(cc3_mro, linear_sv, 0, 0);
 306                 if(he_cc3_mro_class) {
 307                     HV* cc3_mro_class = (HV*)SvRV(HeVAL(he_cc3_mro_class));
 308                     SV** svp_cc3_mro_class_methods = hv_fetch(cc3_mro_class, "methods", 7, 0);
 309                     if(svp_cc3_mro_class_methods) {
 310                         HV* cc3_mro_class_methods = (HV*)SvRV(*svp_cc3_mro_class_methods);
 311                         if(hv_exists_ent(cc3_mro_class_methods, sub_sv, 0))
 312                             continue;
 313                     }
 314                 }
 315             }
 316
 317             cstash = gv_stashsv(linear_sv, FALSE);
 318
 319             if (!cstash) {
 320                 if (ckWARN(WARN_MISC))
 321                     Perl_warner(aTHX_ packWARN(WARN_MISC), "Can't locate package %"SVf" for @%s::ISA",
 322                         (void*)linear_sv, hvname);
 323                 continue;
 324             }
 325
 326             assert(cstash);
 327
 328             gvp = (GV**)hv_fetch(cstash, subname, subname_len, 0);
 329             if (!gvp) continue;
 330
 331             candidate = *gvp;
 332             assert(candidate);
 333
 334             if (SvTYPE(candidate) != SVt_PVGV)
 335                 gv_init(candidate, cstash, subname, subname_len, TRUE);
 336             if (SvTYPE(candidate) == SVt_PVGV && (cand_cv = GvCV(candidate)) && !GvCVGEN(candidate)) {
 337                 SvREFCNT_inc((SV*)cand_cv);
 338                 /* XXX store result in cache */
 339                 /* hv_store_ent(nmcache, newSVsv(sv), (SV*)cand_cv, 0); */
 340                 return (SV*)cand_cv;
 341             }
 342         }
 343     }
 344
 345     /* XXX store undef in cache */
 346     /* hv_store_ent(nmcache, newSVsv(sv), &PL_sv_undef, 0); */
 347     if(throw_nomethod)
 348         croak("No next::method '%s' found for %s", subname, hvname);
 349     return &PL_sv_undef;
 350 }
 351
 352 XS(XS_Class_C3_XS_calculateMRO);
 353 XS(XS_Class_C3_XS_calculateMRO)
 354 {
 355 #ifdef dVAR
 356     dVAR; dXSARGS;
 357 #else
 358     dXSARGS;
 359 #endif
 360
 361     SV* classname;
 362     HV* class_stash;
 363     HV* cache = NULL;
 364     AV* res;
 365     I32 res_items;
 366     I32 ret_items;
 367     SV** res_ptr;
 368
 369     if(items < 1 || items > 2)
 370         croak("Usage: calculateMRO(classname[, cache])");
 371
 372     classname = ST(0);
 373     if(items == 2) cache = (HV*)ST(1);
 374
 375     class_stash = gv_stashsv(classname, 0);
 376     if(!class_stash) croak("No such class: '%s'!", SvPV_nolen(classname));
 377
 378     res = (AV*)sv_2mortal((SV*)__mro_linear_isa_c3(class_stash, cache, 0));
 379
 380     res_items = ret_items = AvFILLp(res) + 1;
 381     res_ptr = AvARRAY(res);
 382
 383     SP -= items;
 384
 385     while(res_items--) {
 386         SV* res_item = *res_ptr++;
 387         XPUSHs(res_item);
 388     }
 389
 390     PUTBACK;
 391
 392     return;
 393 }
 394
 395 XS(XS_next_can);
 396 XS(XS_next_can)
 397 {
 398 #ifdef dVAR
 399     dVAR; dXSARGS;
 400 #else
 401     dXSARGS;
 402 #endif
 403
 404     SV* self = ST(0);
 405     SV* methcv = __nextcan(self, 0);
 406
 407     PERL_UNUSED_VAR(items);
 408
 409     if(methcv == &PL_sv_undef) {
 410         ST(0) = &PL_sv_undef;
 411     }
 412     else {
 413         ST(0) = sv_2mortal(newRV_inc(methcv));
 414     }
 415
 416     XSRETURN(1);
 417 }
 418
 419 XS(XS_next_method);
 420 XS(XS_next_method)
 421 {
 422     dMARK;
 423     dAX;
 424     SV* self = ST(0);
 425     SV* methcv = __nextcan(self, 1);
 426
 427     PL_markstack_ptr++;
 428     call_sv(methcv, GIMME_V);
 429 }
 430
 431 XS(XS_maybe_next_method);
 432 XS(XS_maybe_next_method)
 433 {
 434     dMARK;
 435     dAX;
 436     SV* self = ST(0);
 437     SV* methcv = __nextcan(self, 0);
 438
 439     if(methcv == &PL_sv_undef) {
 440         ST(0) = &PL_sv_undef;
 441         XSRETURN(1);
 442     }
 443
 444     PL_markstack_ptr++;
 445     call_sv(methcv, GIMME_V);
 446 }
 447
 448 MODULE = Class::C3::XS  PACKAGE = Class::C3::XS
 449
 450 BOOT:
 451     newXS("Class::C3::XS::calculateMRO", XS_Class_C3_XS_calculateMRO, __FILE__);
 452     newXS("next::can", XS_next_can, __FILE__);
 453     newXS("next::method", XS_next_method, __FILE__);
 454     newXS("maybe::next::method", XS_maybe_next_method, __FILE__);