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 /* This is %next::METHOD_CACHE */
  12 STATIC HV* nmcache;
  13
  14 AV*
  15 __mro_linear_isa_c3(pTHX_ HV* stash, HV* cache, I32 level)
  16 {
  17     AV* retval;
  18     GV** gvp;
  19     GV* gv;
  20     AV* isa;
  21     const char* stashname;
  22     STRLEN stashname_len;
  23
  24     assert(stash);
  25     assert(HvAUX(stash));
  26
  27     stashname = HvNAME(stash);
  28     stashname_len = strlen(stashname);
  29     if (!stashname)
  30       Perl_croak(aTHX_
  31                  "Can't linearize anonymous symbol table");
  32
  33     if (level > 100)
  34         Perl_croak(aTHX_ "Recursive inheritance detected in package '%s'",
  35               stashname);
  36
  37     if(!cache) {
  38         cache = (HV*)sv_2mortal((SV*)newHV());
  39     }
  40     else {
  41         SV** cache_entry = hv_fetch(cache, stashname, stashname_len, 0);
  42         if(cache_entry)
  43             return (AV*)SvREFCNT_inc(*cache_entry);
  44     }
  45
  46     /* not in cache, make a new one */
  47
  48     retval = (AV*)sv_2mortal((SV*)newAV());
  49     av_push(retval, newSVpvn(stashname, stashname_len)); /* us first */
  50
  51     gvp = (GV**)hv_fetch(stash, "ISA", 3, FALSE);
  52     isa = (gvp && (gv = *gvp) && gv != (GV*)&PL_sv_undef) ? GvAV(gv) : NULL;
  53
  54     if(isa && AvFILLp(isa) >= 0) {
  55         SV** seqs_ptr;
  56         I32 seqs_items;
  57         HV* tails = (HV*)sv_2mortal((SV*)newHV());
  58         AV* seqs = (AV*)sv_2mortal((SV*)newAV());
  59         I32 items = AvFILLp(isa) + 1;
  60         SV** isa_ptr = AvARRAY(isa);
  61         while(items--) {
  62             AV* isa_lin;
  63             SV* isa_item = *isa_ptr++;
  64             HV* isa_item_stash = gv_stashsv(isa_item, 0);
  65             if(!isa_item_stash) {
  66                 isa_lin = newAV();
  67                 av_push(isa_lin, newSVsv(isa_item));
  68             }
  69             else {
  70                 isa_lin = (AV*)sv_2mortal((SV*)__mro_linear_isa_c3(aTHX_ isa_item_stash, cache, level + 1)); /* recursion */
  71             }
  72             av_push(seqs, (SV*)av_make(AvFILLp(isa_lin)+1, AvARRAY(isa_lin)));
  73         }
  74         av_push(seqs, (SV*)av_make(AvFILLp(isa)+1, AvARRAY(isa)));
  75
  76         seqs_ptr = AvARRAY(seqs);
  77         seqs_items = AvFILLp(seqs) + 1;
  78         while(seqs_items--) {
  79             AV* seq = (AV*)*seqs_ptr++;
  80             I32 seq_items = AvFILLp(seq);
  81             if(seq_items > 0) {
  82                 SV** seq_ptr = AvARRAY(seq) + 1;
  83                 while(seq_items--) {
  84                     SV* seqitem = *seq_ptr++;
  85                     HE* he = hv_fetch_ent(tails, seqitem, 0, 0);
  86                     if(!he) {
  87                         hv_store_ent(tails, seqitem, newSViv(1), 0);
  88                     }
  89                     else {
  90                         SV* val = HeVAL(he);
  91                         sv_inc(val);
  92                     }
  93                 }
  94             }
  95         }
  96
  97         while(1) {
  98             SV* seqhead = NULL;
  99             SV* cand = NULL;
 100             SV* winner = NULL;
 101             SV* val;
 102             HE* tail_entry;
 103             AV* seq;
 104             SV** avptr = AvARRAY(seqs);
 105             items = AvFILLp(seqs)+1;
 106             while(items--) {
 107                 SV** svp;
 108                 seq = (AV*)*avptr++;
 109                 if(AvFILLp(seq) < 0) continue;
 110                 svp = av_fetch(seq, 0, 0);
 111                 seqhead = *svp;
 112                 if(!winner) {
 113                     cand = seqhead;
 114                     if((tail_entry = hv_fetch_ent(tails, cand, 0, 0))
 115                        && (val = HeVAL(tail_entry))
 116                        && (SvIVx(val) > 0))
 117                            continue;
 118                     winner = newSVsv(cand);
 119                     av_push(retval, winner);
 120                 }
 121                 if(!sv_cmp(seqhead, winner)) {
 122
 123                     /* this is basically shift(@seq) in void context */
 124                     SvREFCNT_dec(*AvARRAY(seq));
 125                     *AvARRAY(seq) = &PL_sv_undef;
 126                     AvARRAY(seq) = AvARRAY(seq) + 1;
 127                     AvMAX(seq)--;
 128                     AvFILLp(seq)--;
 129
 130                     if(AvFILLp(seq) < 0) continue;
 131                     svp = av_fetch(seq, 0, 0);
 132                     seqhead = *svp;
 133                     tail_entry = hv_fetch_ent(tails, seqhead, 0, 0);
 134                     val = HeVAL(tail_entry);
 135                     sv_dec(val);
 136                 }
 137             }
 138             if(!cand) break;
 139             if(!winner)
 140                 Perl_croak(aTHX_ "Inconsistent hierarchy during C3 merge of class '%s': "
 141                     "merging failed on parent '%s'", stashname, SvPV_nolen(cand));
 142         }
 143     }
 144
 145     SvREADONLY_on(retval);
 146     SvREFCNT_inc(retval); /* for cache storage */
 147     SvREFCNT_inc(retval); /* for return */
 148     hv_store(cache, stashname, stashname_len, (SV*)retval, 0);
 149     return retval;
 150 }
 151
 152 STATIC I32
 153 __dopoptosub_at(const PERL_CONTEXT *cxstk, I32 startingblock) {
 154     I32 i;
 155     for (i = startingblock; i >= 0; i--) {
 156         if(CxTYPE((PERL_CONTEXT*)(&cxstk[i])) == CXt_SUB) return i;
 157     }
 158     return i;
 159 }
 160
 161 STATIC SV*
 162 __nextcan(pTHX_ SV* self, I32 throw_nomethod)
 163 {
 164     register I32 cxix;
 165     register const PERL_CONTEXT *ccstack = cxstack;
 166     const PERL_SI *top_si = PL_curstackinfo;
 167     HV* selfstash;
 168     GV* cvgv;
 169     SV *stashname;
 170     const char *fq_subname;
 171     const char *subname;
 172     STRLEN fq_subname_len;
 173     STRLEN stashname_len;
 174     STRLEN subname_len;
 175     SV* sv;
 176     GV** gvp;
 177     AV* linear_av;
 178     SV** linear_svp;
 179     SV* linear_sv;
 180     HV* cstash;
 181     GV* candidate = NULL;
 182     CV* cand_cv = NULL;
 183     const char *hvname;
 184     I32 items;
 185     HE* cache_entry;
 186     SV* cachekey;
 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     /* cachekey = "objpkg|context::method::name" */
 261     cachekey = sv_2mortal(newSVpv(hvname, 0));
 262     sv_catpvn(cachekey, "|", 1);
 263     sv_catsv(cachekey, sv);
 264
 265     if((cache_entry = hv_fetch_ent(nmcache, cachekey, 0, 0))) {
 266         SV* val = HeVAL(cache_entry);
 267         if(val == &PL_sv_undef) {
 268             if(throw_nomethod)
 269                 croak("No next::method '%s' found for %s", subname, hvname);
 270             return &PL_sv_undef;
 271         }
 272         return SvREFCNT_inc(val);
 273     }
 274
 275     /* beyond here is just for cache misses, so perf isn't as critical */
 276
 277     stashname_len = subname - fq_subname - 2;
 278     stashname = sv_2mortal(newSVpvn(fq_subname, stashname_len));
 279
 280     linear_av = (AV*)sv_2mortal((SV*)__mro_linear_isa_c3(aTHX_ selfstash, NULL, 0));
 281
 282     linear_svp = AvARRAY(linear_av);
 283     items = AvFILLp(linear_av) + 1;
 284
 285     while (items--) {
 286         linear_sv = *linear_svp++;
 287         assert(linear_sv);
 288         if(sv_eq(linear_sv, stashname))
 289             break;
 290     }
 291
 292     if(items > 0) {
 293         SV* sub_sv = sv_2mortal(newSVpv(subname, subname_len));
 294         HV* cc3_mro = get_hv("Class::C3::MRO", 0);
 295
 296         while (items--) {
 297             linear_sv = *linear_svp++;
 298             assert(linear_sv);
 299
 300             if(cc3_mro) {
 301                 HE* he_cc3_mro_class = hv_fetch_ent(cc3_mro, linear_sv, 0, 0);
 302                 if(he_cc3_mro_class) {
 303                     HV* cc3_mro_class = (HV*)SvRV(HeVAL(he_cc3_mro_class));
 304                     SV** svp_cc3_mro_class_methods = hv_fetch(cc3_mro_class, "methods", 7, 0);
 305                     if(svp_cc3_mro_class_methods) {
 306                         HV* cc3_mro_class_methods = (HV*)SvRV(*svp_cc3_mro_class_methods);
 307                         if(hv_exists_ent(cc3_mro_class_methods, sub_sv, 0))
 308                             continue;
 309                     }
 310                 }
 311             }
 312
 313             cstash = gv_stashsv(linear_sv, FALSE);
 314
 315             if (!cstash) {
 316                 if (ckWARN(WARN_MISC))
 317                     Perl_warner(aTHX_ packWARN(WARN_MISC), "Can't locate package %"SVf" for @%s::ISA",
 318                         (void*)linear_sv, hvname);
 319                 continue;
 320             }
 321
 322             assert(cstash);
 323
 324             gvp = (GV**)hv_fetch(cstash, subname, subname_len, 0);
 325             if (!gvp) continue;
 326
 327             candidate = *gvp;
 328             assert(candidate);
 329
 330             if (SvTYPE(candidate) != SVt_PVGV)
 331                 gv_init(candidate, cstash, subname, subname_len, TRUE);
 332             if (SvTYPE(candidate) == SVt_PVGV && (cand_cv = GvCV(candidate)) && !GvCVGEN(candidate)) {
 333                 SvREFCNT_inc((SV*)cand_cv);
 334                 hv_store_ent(nmcache, newSVsv(cachekey), (SV*)cand_cv, 0);
 335                 return (SV*)cand_cv;
 336             }
 337         }
 338     }
 339
 340     hv_store_ent(nmcache, newSVsv(cachekey), &PL_sv_undef, 0);
 341     if(throw_nomethod)
 342         croak("No next::method '%s' found for %s", subname, hvname);
 343     return &PL_sv_undef;
 344 }
 345
 346 XS(XS_Class_C3_XS_calculateMRO);
 347 XS(XS_Class_C3_XS_calculateMRO)
 348 {
 349 #ifdef dVAR
 350     dVAR; dXSARGS;
 351 #else
 352     dXSARGS;
 353 #endif
 354
 355     SV* classname;
 356     HV* class_stash;
 357     HV* cache = NULL;
 358     AV* res;
 359     I32 res_items;
 360     I32 ret_items;
 361     SV** res_ptr;
 362
 363     if(items < 1 || items > 2)
 364         croak("Usage: calculateMRO(classname[, cache])");
 365
 366     classname = ST(0);
 367     if(items == 2) cache = (HV*)SvRV(ST(1));
 368
 369     class_stash = gv_stashsv(classname, 0);
 370     if(!class_stash) croak("No such class: '%s'!", SvPV_nolen(classname));
 371
 372     res = (AV*)sv_2mortal((SV*)__mro_linear_isa_c3(aTHX_ class_stash, cache, 0));
 373
 374     res_items = ret_items = AvFILLp(res) + 1;
 375     res_ptr = AvARRAY(res);
 376
 377     SP -= items;
 378
 379     while(res_items--) {
 380         SV* res_item = *res_ptr++;
 381         XPUSHs(res_item);
 382     }
 383
 384     PUTBACK;
 385
 386     return;
 387 }
 388
 389 XS(XS_next_can);
 390 XS(XS_next_can)
 391 {
 392 #ifdef dVAR
 393     dVAR; dXSARGS;
 394 #else
 395     dXSARGS;
 396 #endif
 397
 398     SV* self = ST(0);
 399     SV* methcv = __nextcan(aTHX_ self, 0);
 400
 401     PERL_UNUSED_VAR(items);
 402
 403     if(methcv == &PL_sv_undef) {
 404         ST(0) = &PL_sv_undef;
 405     }
 406     else {
 407         ST(0) = sv_2mortal(newRV_inc(methcv));
 408     }
 409
 410     XSRETURN(1);
 411 }
 412
 413 XS(XS_next_method);
 414 XS(XS_next_method)
 415 {
 416     dMARK;
 417     dAX;
 418     SV* self = ST(0);
 419     SV* methcv = __nextcan(aTHX_ self, 1);
 420
 421     PL_markstack_ptr++;
 422     call_sv(methcv, GIMME_V);
 423 }
 424
 425 XS(XS_maybe_next_method);
 426 XS(XS_maybe_next_method)
 427 {
 428     dMARK;
 429     dAX;
 430     SV* self = ST(0);
 431     SV* methcv = __nextcan(aTHX_ self, 0);
 432
 433     if(methcv == &PL_sv_undef) {
 434         ST(0) = &PL_sv_undef;
 435         XSRETURN(1);
 436     }
 437
 438     PL_markstack_ptr++;
 439     call_sv(methcv, GIMME_V);
 440 }
 441
 442 MODULE = Class::C3::XS  PACKAGE = Class::C3::XS
 443
 444 BOOT:
 445     nmcache = get_hv("next::METHOD_CACHE", 1);
 446     newXS("Class::C3::XS::calculateMRO", XS_Class_C3_XS_calculateMRO, __FILE__);
 447     newXS("next::can", XS_next_can, __FILE__);
 448     newXS("next::method", XS_next_method, __FILE__);
 449     newXS("maybe::next::method", XS_maybe_next_method, __FILE__);