ext/threads/shared/shared.xs

   1 /*    shared.xs
   2  *
   3  *    Copyright (c) 2001-2002, Larry Wall
   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  * "Hand any two wizards a piece of rope and they would instinctively pull in
   9  * opposite directions."
  10  *                         --Sourcery
  11  *
  12  * Contributed by Arthur Bergman arthur@contiller.se
  13  * pulled in the (an)other direction by Nick Ing-Simmons nick@ing-simmons.net
  14  */
  15
  16 #define PERL_NO_GET_CONTEXT
  17 #include "EXTERN.h"
  18 #include "perl.h"
  19 #include "XSUB.h"
  20
  21 #ifdef USE_ITHREADS
  22
  23 #define SHAREDSvPTR(a)      ((a)->sv)
  24
  25 /*
  26  * The shared things need an intepreter to live in ...
  27  */
  28 PerlInterpreter *PL_sharedsv_space;             /* The shared sv space */
  29 /* To access shared space we fake aTHX in this scope and thread's context */
  30
  31 /* bug #24255: we include ENTER+SAVETMPS/FREETMPS+LEAVE with
  32  * SHARED_CONTEXT/CALLER_CONTEXT macros, so that any mortals etc created
  33  * while in the shared interpreter context don't languish */
  34
  35 #define SHARED_CONTEXT \
  36     STMT_START {                                        \
  37         PERL_SET_CONTEXT((aTHX = PL_sharedsv_space));   \
  38         ENTER;                                          \
  39         SAVETMPS;                                       \
  40     } STMT_END
  41
  42 /* So we need a way to switch back to the caller's context... */
  43 /* So we declare _another_ copy of the aTHX variable ... */
  44 #define dTHXc PerlInterpreter *caller_perl = aTHX
  45
  46 /* and use it to switch back */
  47 #define CALLER_CONTEXT                                  \
  48     STMT_START {                                        \
  49         FREETMPS;                                       \
  50         LEAVE;                                          \
  51         PERL_SET_CONTEXT((aTHX = caller_perl));         \
  52     } STMT_END
  53
  54 /*
  55  * Only one thread at a time is allowed to mess with shared space.
  56  */
  57
  58 typedef struct
  59 {
  60  perl_mutex              mutex;
  61  PerlInterpreter        *owner;
  62  I32                     locks;
  63  perl_cond               cond;
  64 #ifdef DEBUG_LOCKS
  65  char *                  file;
  66  int                     line;
  67 #endif
  68 } recursive_lock_t;
  69
  70 recursive_lock_t PL_sharedsv_lock;       /* Mutex protecting the shared sv space */
  71
  72 void
  73 recursive_lock_init(pTHX_ recursive_lock_t *lock)
  74 {
  75     Zero(lock,1,recursive_lock_t);
  76     MUTEX_INIT(&lock->mutex);
  77     COND_INIT(&lock->cond);
  78 }
  79
  80 void
  81 recursive_lock_destroy(pTHX_ recursive_lock_t *lock)
  82 {
  83     MUTEX_DESTROY(&lock->mutex);
  84     COND_DESTROY(&lock->cond);
  85 }
  86
  87 void
  88 recursive_lock_release(pTHX_ recursive_lock_t *lock)
  89 {
  90     MUTEX_LOCK(&lock->mutex);
  91     if (lock->owner != aTHX) {
  92         MUTEX_UNLOCK(&lock->mutex);
  93     }
  94     else {
  95         if (--lock->locks == 0) {
  96             lock->owner = NULL;
  97             COND_SIGNAL(&lock->cond);
  98         }
  99     }
 100     MUTEX_UNLOCK(&lock->mutex);
 101 }
 102
 103 void
 104 recursive_lock_acquire(pTHX_ recursive_lock_t *lock,char *file,int line)
 105 {
 106     assert(aTHX);
 107     MUTEX_LOCK(&lock->mutex);
 108     if (lock->owner == aTHX) {
 109         lock->locks++;
 110     }
 111     else {
 112         while (lock->owner) {
 113 #ifdef DEBUG_LOCKS
 114             Perl_warn(aTHX_ " %p waiting - owned by %p %s:%d\n",
 115                       aTHX, lock->owner, lock->file, lock->line);
 116 #endif
 117             COND_WAIT(&lock->cond,&lock->mutex);
 118         }
 119         lock->locks = 1;
 120         lock->owner = aTHX;
 121 #ifdef DEBUG_LOCKS
 122         lock->file  = file;
 123         lock->line  = line;
 124 #endif
 125     }
 126     MUTEX_UNLOCK(&lock->mutex);
 127     SAVEDESTRUCTOR_X(recursive_lock_release,lock);
 128 }
 129
 130 #define ENTER_LOCK         STMT_START { \
 131                               ENTER; \
 132                               recursive_lock_acquire(aTHX_ &PL_sharedsv_lock, __FILE__, __LINE__);   \
 133                             } STMT_END
 134
 135 #define LEAVE_LOCK       LEAVE
 136
 137
 138 /* A common idiom is to acquire access and switch in ... */
 139 #define SHARED_EDIT         STMT_START {        \
 140                                 ENTER_LOCK;     \
 141                                 SHARED_CONTEXT; \
 142                             } STMT_END
 143
 144 /* then switch out and release access. */
 145 #define SHARED_RELEASE     STMT_START { \
 146                                 CALLER_CONTEXT; \
 147                                 LEAVE_LOCK;     \
 148                             } STMT_END
 149
 150
 151 /*
 152
 153   Shared SV
 154
 155   Shared SV is a structure for keeping the backend storage
 156   of shared svs.
 157
 158   Shared-ness really only needs the SV * - the rest is for locks.
 159   (Which suggests further space optimization ... )
 160
 161 */
 162
 163 typedef struct {
 164     SV                 *sv;             /* The actual SV - in shared space */
 165     recursive_lock_t    lock;
 166     perl_cond           user_cond;      /* For user-level conditions */
 167 } shared_sv;
 168
 169 /* The SV in shared-space has a back-pointer to the shared_sv
 170    struct associated with it PERL_MAGIC_ext.
 171
 172    The vtable used has just one entry - when the SV goes away
 173    we free the memory for the above.
 174
 175  */
 176
 177 int
 178 sharedsv_shared_mg_free(pTHX_ SV *sv, MAGIC *mg)
 179 {
 180     shared_sv *shared = (shared_sv *) mg->mg_ptr;
 181     assert( aTHX == PL_sharedsv_space );
 182     if (shared) {
 183         recursive_lock_destroy(aTHX_ &shared->lock);
 184         COND_DESTROY(&shared->user_cond);
 185         PerlMemShared_free(shared);
 186         mg->mg_ptr = NULL;
 187     }
 188     return 0;
 189 }
 190
 191 MGVTBL sharedsv_shared_vtbl = {
 192  0,                             /* get */
 193  0,                             /* set */
 194  0,                             /* len */
 195  0,                             /* clear */
 196  sharedsv_shared_mg_free,       /* free */
 197  0,                             /* copy */
 198  0,                             /* dup */
 199 };
 200
 201 /* Access to shared things is heavily based on MAGIC - in mg.h/mg.c/sv.c sense */
 202
 203 /* In any thread that has access to a shared thing there is a "proxy"
 204    for it in its own space which has 'MAGIC' associated which accesses
 205    the shared thing.
 206  */
 207
 208 MGVTBL sharedsv_scalar_vtbl;    /* scalars have this vtable */
 209 MGVTBL sharedsv_array_vtbl;     /* hashes and arrays have this - like 'tie' */
 210 MGVTBL sharedsv_elem_vtbl;      /* elements of hashes and arrays have this
 211                                    _AS WELL AS_ the scalar magic */
 212
 213 /* The sharedsv_elem_vtbl associates the element with the array/hash and
 214    the sharedsv_scalar_vtbl associates it with the value
 215  */
 216
 217
 218 /* Accessor to convert threads::shared::tie objects back shared_sv * */
 219 shared_sv *
 220 SV_to_sharedsv(pTHX_ SV *sv)
 221 {
 222     shared_sv *shared = 0;
 223     if (SvROK(sv))
 224      {
 225       shared = INT2PTR(shared_sv *, SvIV(SvRV(sv)));
 226      }
 227     return shared;
 228 }
 229
 230 =for apidoc sharedsv_find
 231
 232 Given a private side SV tries to find if the SV has a shared backend,
 233 by looking for the magic.
 234
 235 =cut
 236
 237 shared_sv *
 238 Perl_sharedsv_find(pTHX_ SV *sv)
 239 {
 240     MAGIC *mg;
 241     if (SvTYPE(sv) >= SVt_PVMG) {
 242         switch(SvTYPE(sv)) {
 243         case SVt_PVAV:
 244         case SVt_PVHV:
 245             if ((mg = mg_find(sv, PERL_MAGIC_tied))
 246                 && mg->mg_virtual == &sharedsv_array_vtbl) {
 247                 return (shared_sv *) mg->mg_ptr;
 248             }
 249             break;
 250         default:
 251             /* This should work for elements as well as they
 252              * have scalar magic as well as their element magic
 253              */
 254             if ((mg = mg_find(sv, PERL_MAGIC_shared_scalar))
 255                 && mg->mg_virtual == &sharedsv_scalar_vtbl) {
 256                 return (shared_sv *) mg->mg_ptr;
 257             }
 258             break;
 259         }
 260     }
 261     /* Just for tidyness of API also handle tie objects */
 262     if (SvROK(sv) && sv_derived_from(sv, "threads::shared::tie")) {
 263         return SV_to_sharedsv(aTHX_ sv);
 264     }
 265     return NULL;
 266 }
 267
 268 /*
 269  *  Almost all the pain is in this routine.
 270  *
 271  */
 272
 273 shared_sv *
 274 Perl_sharedsv_associate(pTHX_ SV **psv, SV *ssv, shared_sv *data)
 275 {
 276     dTHXc;
 277     MAGIC *mg = 0;
 278     SV *sv    = (psv) ? *psv : Nullsv;
 279
 280     /* If we are asked for an private ops we need a thread */
 281     assert ( aTHX !=  PL_sharedsv_space );
 282
 283     /* To avoid need for recursive locks require caller to hold lock */
 284     assert ( PL_sharedsv_lock.owner == aTHX );
 285
 286     /* First try and get existing global data structure */
 287
 288     /* Try shared SV as 1st choice */
 289     if (!data && ssv && SvTYPE(ssv) >= SVt_PVMG) {
 290         if( (mg = mg_find(ssv, PERL_MAGIC_ext)) ){
 291             data = (shared_sv *) mg->mg_ptr;
 292         }
 293     }
 294
 295     /* Next see if private SV is associated with something */
 296     if (!data && sv) {
 297         data = Perl_sharedsv_find(aTHX_ sv);
 298     }
 299
 300     /* If neither of those then create a new one */
 301     if (!data) {
 302             SHARED_CONTEXT;
 303             if (!ssv) {
 304                 ssv = newSV(0);
 305                 SvREFCNT(ssv) = 0;
 306             }
 307             data = PerlMemShared_malloc(sizeof(shared_sv));
 308             Zero(data,1,shared_sv);
 309             SHAREDSvPTR(data) = ssv;
 310             /* Tag shared side SV with data pointer */
 311             sv_magicext(ssv, ssv, PERL_MAGIC_ext, &sharedsv_shared_vtbl,
 312                    (char *)data, 0);
 313             recursive_lock_init(aTHX_ &data->lock);
 314             COND_INIT(&data->user_cond);
 315             CALLER_CONTEXT;
 316     }
 317
 318     if (!ssv)
 319         ssv = SHAREDSvPTR(data);
 320     if (!SHAREDSvPTR(data))
 321         SHAREDSvPTR(data) = ssv;
 322
 323     /* If we know type upgrade shared side SV */
 324     if (sv && SvTYPE(ssv) < SvTYPE(sv)) {
 325         SHARED_CONTEXT;
 326         sv_upgrade(ssv, SvTYPE(*psv));
 327         if (SvTYPE(ssv) == SVt_PVAV)    /* #24061 */
 328             AvREAL_on(ssv);
 329         CALLER_CONTEXT;
 330     }
 331
 332     /* Now if requested allocate private SV */
 333     if (psv && !sv) {
 334         *psv = sv = newSV(0);
 335     }
 336
 337     /* Finally if private SV exists check and add magic */
 338     if (sv) {
 339         MAGIC *mg = 0;
 340         if (SvTYPE(sv) < SvTYPE(ssv)) {
 341             sv_upgrade(sv, SvTYPE(ssv));
 342         }
 343         switch(SvTYPE(sv)) {
 344         case SVt_PVAV:
 345         case SVt_PVHV:
 346             if (!(mg = mg_find(sv, PERL_MAGIC_tied))
 347                 || mg->mg_virtual != &sharedsv_array_vtbl
 348                 || (shared_sv *) mg->mg_ptr != data) {
 349                 SV *obj = newSV(0);
 350                 sv_setref_iv(obj, "threads::shared::tie",PTR2IV(data));
 351                 if (mg) {
 352                     sv_unmagic(sv, PERL_MAGIC_tied);
 353                 }
 354                 mg = sv_magicext(sv, obj, PERL_MAGIC_tied, &sharedsv_array_vtbl,
 355                                 (char *) data, 0);
 356                 mg->mg_flags |= (MGf_COPY|MGf_DUP);
 357                 SvREFCNT_inc(ssv);
 358                 SvREFCNT_dec(obj);
 359                 if(SvOBJECT(ssv)) {
 360                   STRLEN len;
 361                   char* stash_ptr = SvPV((SV*) SvSTASH(ssv), len);
 362                   HV* stash = gv_stashpvn(stash_ptr, len, TRUE);
 363                   SvOBJECT_on(sv);
 364                   SvSTASH(sv) = (HV*)SvREFCNT_inc(stash);
 365                 }
 366             }
 367             break;
 368
 369         default:
 370             if ((SvTYPE(sv) < SVt_PVMG)
 371                 || !(mg = mg_find(sv, PERL_MAGIC_shared_scalar))
 372                 || mg->mg_virtual != &sharedsv_scalar_vtbl
 373                 || (shared_sv *) mg->mg_ptr != data) {
 374                 if (mg) {
 375                     sv_unmagic(sv, PERL_MAGIC_shared_scalar);
 376                 }
 377                 mg = sv_magicext(sv, Nullsv, PERL_MAGIC_shared_scalar,
 378                                 &sharedsv_scalar_vtbl, (char *)data, 0);
 379                 mg->mg_flags |= (MGf_COPY|MGf_DUP);
 380                 SvREFCNT_inc(ssv);
 381             }
 382             break;
 383         }
 384         assert ( Perl_sharedsv_find(aTHX_ *psv) == data );
 385     }
 386     return data;
 387 }
 388
 389 void
 390 Perl_sharedsv_free(pTHX_ shared_sv *shared)
 391 {
 392     if (shared) {
 393         dTHXc;
 394         SHARED_EDIT;
 395         SvREFCNT_dec(SHAREDSvPTR(shared));
 396         SHARED_RELEASE;
 397     }
 398 }
 399
 400 void
 401 Perl_sharedsv_share(pTHX_ SV *sv)
 402 {
 403     switch(SvTYPE(sv)) {
 404     case SVt_PVGV:
 405         Perl_croak(aTHX_ "Cannot share globs yet");
 406         break;
 407
 408     case SVt_PVCV:
 409         Perl_croak(aTHX_ "Cannot share subs yet");
 410         break;
 411
 412     default:
 413         ENTER_LOCK;
 414         Perl_sharedsv_associate(aTHX_ &sv, 0, 0);
 415         LEAVE_LOCK;
 416         SvSETMAGIC(sv);
 417         break;
 418     }
 419 }
 420
 421 /* MAGIC (in mg.h sense) hooks */
 422
 423 int
 424 sharedsv_scalar_mg_get(pTHX_ SV *sv, MAGIC *mg)
 425 {
 426     shared_sv *shared = (shared_sv *) mg->mg_ptr;
 427     assert(shared);
 428
 429     ENTER_LOCK;
 430     if (SHAREDSvPTR(shared)) {
 431         if (SvROK(SHAREDSvPTR(shared))) {
 432             SV *obj = Nullsv;
 433             Perl_sharedsv_associate(aTHX_ &obj, SvRV(SHAREDSvPTR(shared)), NULL);
 434             sv_setsv_nomg(sv, &PL_sv_undef);
 435             SvRV(sv) = obj;
 436             SvROK_on(sv);
 437
 438         }
 439         else {
 440             sv_setsv_nomg(sv, SHAREDSvPTR(shared));
 441         }
 442     }
 443     LEAVE_LOCK;
 444     return 0;
 445 }
 446
 447 void
 448 sharedsv_scalar_store(pTHX_ SV *sv, shared_sv *shared)
 449 {
 450     dTHXc;
 451     bool allowed = TRUE;
 452     if (SvROK(sv)) {
 453         shared_sv* target = Perl_sharedsv_find(aTHX_ SvRV(sv));
 454         if (target) {
 455             SV *tmp;
 456             SHARED_CONTEXT;
 457             tmp = newRV(SHAREDSvPTR(target));
 458             sv_setsv_nomg(SHAREDSvPTR(shared), tmp);
 459             SvREFCNT_dec(tmp);
 460             if(SvOBJECT(SvRV(sv))) {
 461               SV* fake_stash = newSVpv(HvNAME(SvSTASH(SvRV(sv))),0);
 462               SvOBJECT_on(SHAREDSvPTR(target));
 463               SvSTASH(SHAREDSvPTR(target)) = (HV*)fake_stash;
 464             }
 465             CALLER_CONTEXT;
 466         }
 467         else {
 468             allowed = FALSE;
 469         }
 470     }
 471     else {
 472         SvTEMP_off(sv);
 473         SHARED_CONTEXT;
 474         sv_setsv_nomg(SHAREDSvPTR(shared), sv);
 475         if(SvOBJECT(sv)) {
 476           SV* fake_stash = newSVpv(HvNAME(SvSTASH(sv)),0);
 477           SvOBJECT_on(SHAREDSvPTR(shared));
 478           SvSTASH(SHAREDSvPTR(shared)) = (HV*)fake_stash;
 479         }
 480         CALLER_CONTEXT;
 481     }
 482     if (!allowed) {
 483         Perl_croak(aTHX_ "Invalid value for shared scalar");
 484     }
 485 }
 486
 487 int
 488 sharedsv_scalar_mg_set(pTHX_ SV *sv, MAGIC *mg)
 489 {
 490     shared_sv *shared;
 491     ENTER_LOCK;
 492     /* We call associate to potentially upgrade shared side SV */
 493     shared = Perl_sharedsv_associate(aTHX_ &sv, Nullsv, (shared_sv *) mg->mg_ptr);
 494     assert(shared);
 495     sharedsv_scalar_store(aTHX_ sv, shared);
 496     LEAVE_LOCK;
 497     return 0;
 498 }
 499
 500 int
 501 sharedsv_scalar_mg_free(pTHX_ SV *sv, MAGIC *mg)
 502 {
 503     shared_sv *shared = (shared_sv *) mg->mg_ptr;
 504 #if 0
 505     assert (SvREFCNT(SHAREDSvPTR(shared)) < 1000);
 506 #endif
 507     Perl_sharedsv_free(aTHX_ shared);
 508     return 0;
 509 }
 510
 511 int
 512 sharedsv_scalar_mg_clear(pTHX_ SV *sv, MAGIC *mg)
 513 {
 514     return 0;
 515 }
 516
 517 /*
 518  * Called during cloning of new threads
 519  */
 520 int
 521 sharedsv_scalar_mg_dup(pTHX_ MAGIC *mg, CLONE_PARAMS *param)
 522 {
 523     shared_sv *shared = (shared_sv *) mg->mg_ptr;
 524     if (shared) {
 525         SvREFCNT_inc(SHAREDSvPTR(shared));
 526     }
 527     return 0;
 528 }
 529
 530 MGVTBL sharedsv_scalar_vtbl = {
 531  sharedsv_scalar_mg_get,        /* get */
 532  sharedsv_scalar_mg_set,        /* set */
 533  0,                             /* len */
 534  sharedsv_scalar_mg_clear,      /* clear */
 535  sharedsv_scalar_mg_free,       /* free */
 536  0,                             /* copy */
 537  sharedsv_scalar_mg_dup         /* dup */
 538 };
 539
 540 /* Now the arrays/hashes stuff */
 541 int
 542 sharedsv_elem_mg_FETCH(pTHX_ SV *sv, MAGIC *mg)
 543 {
 544     dTHXc;
 545     shared_sv *shared = SV_to_sharedsv(aTHX_ mg->mg_obj);
 546     shared_sv *target = Perl_sharedsv_find(aTHX_ sv);
 547     SV** svp;
 548
 549     assert ( shared );
 550     assert ( SHAREDSvPTR(shared) );
 551
 552     ENTER_LOCK;
 553     if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
 554         assert ( mg->mg_ptr == 0 );
 555         SHARED_CONTEXT;
 556         svp = av_fetch((AV*) SHAREDSvPTR(shared), mg->mg_len, 0);
 557     }
 558     else {
 559         char *key = mg->mg_ptr;
 560         STRLEN len = mg->mg_len;
 561         assert ( mg->mg_ptr != 0 );
 562         if (mg->mg_len == HEf_SVKEY) {
 563            key = SvPV((SV *) mg->mg_ptr, len);
 564         }
 565         SHARED_CONTEXT;
 566         svp = hv_fetch((HV*) SHAREDSvPTR(shared), key, len, 0);
 567     }
 568     CALLER_CONTEXT;
 569     if (svp) {
 570         /* Exists in the array */
 571         target = Perl_sharedsv_associate(aTHX_ &sv, *svp, target);
 572         sv_setsv(sv, *svp);
 573     }
 574     else {
 575         /* Not in the array */
 576         sv_setsv(sv, &PL_sv_undef);
 577     }
 578     LEAVE_LOCK;
 579     return 0;
 580 }
 581
 582 int
 583 sharedsv_elem_mg_STORE(pTHX_ SV *sv, MAGIC *mg)
 584 {
 585     dTHXc;
 586     shared_sv *shared = SV_to_sharedsv(aTHX_ mg->mg_obj);
 587     shared_sv *target;
 588     SV **svp;
 589     /* Theory - SV itself is magically shared - and we have ordered the
 590        magic such that by the time we get here it has been stored
 591        to its shared counterpart
 592      */
 593     ENTER_LOCK;
 594     assert(shared);
 595     assert(SHAREDSvPTR(shared));
 596     if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
 597         assert ( mg->mg_ptr == 0 );
 598         SHARED_CONTEXT;
 599         svp = av_fetch((AV*) SHAREDSvPTR(shared), mg->mg_len, 1);
 600     }
 601     else {
 602         char *key = mg->mg_ptr;
 603         STRLEN len = mg->mg_len;
 604         assert ( mg->mg_ptr != 0 );
 605         if (mg->mg_len == HEf_SVKEY)
 606            key = SvPV((SV *) mg->mg_ptr, len);
 607         SHARED_CONTEXT;
 608         svp = hv_fetch((HV*) SHAREDSvPTR(shared), key, len, 1);
 609     }
 610     CALLER_CONTEXT;
 611     target = Perl_sharedsv_associate(aTHX_ &sv, *svp, 0);
 612     sharedsv_scalar_store(aTHX_ sv, target);
 613     LEAVE_LOCK;
 614     return 0;
 615 }
 616
 617 int
 618 sharedsv_elem_mg_DELETE(pTHX_ SV *sv, MAGIC *mg)
 619 {
 620     dTHXc;
 621     MAGIC *shmg;
 622     shared_sv *shared = SV_to_sharedsv(aTHX_ mg->mg_obj);
 623     ENTER_LOCK;
 624     sharedsv_elem_mg_FETCH(aTHX_ sv, mg);
 625     if ((shmg = mg_find(sv, PERL_MAGIC_shared_scalar)))
 626         sharedsv_scalar_mg_get(aTHX_ sv, shmg);
 627     if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
 628         SHARED_CONTEXT;
 629         av_delete((AV*) SHAREDSvPTR(shared), mg->mg_len, G_DISCARD);
 630     }
 631     else {
 632         char *key = mg->mg_ptr;
 633         STRLEN len = mg->mg_len;
 634         assert ( mg->mg_ptr != 0 );
 635         if (mg->mg_len == HEf_SVKEY)
 636            key = SvPV((SV *) mg->mg_ptr, len);
 637         SHARED_CONTEXT;
 638         hv_delete((HV*) SHAREDSvPTR(shared), key, len, G_DISCARD);
 639     }
 640     CALLER_CONTEXT;
 641     LEAVE_LOCK;
 642     return 0;
 643 }
 644
 645 int
 646 sharedsv_elem_mg_free(pTHX_ SV *sv, MAGIC *mg)
 647 {
 648     Perl_sharedsv_free(aTHX_ SV_to_sharedsv(aTHX_ mg->mg_obj));
 649     return 0;
 650 }
 651
 652 int
 653 sharedsv_elem_mg_dup(pTHX_ MAGIC *mg, CLONE_PARAMS *param)
 654 {
 655     shared_sv *shared = SV_to_sharedsv(aTHX_ mg->mg_obj);
 656     SvREFCNT_inc(SHAREDSvPTR(shared));
 657     mg->mg_flags |= MGf_DUP;
 658     return 0;
 659 }
 660
 661 MGVTBL sharedsv_elem_vtbl = {
 662  sharedsv_elem_mg_FETCH,        /* get */
 663  sharedsv_elem_mg_STORE,        /* set */
 664  0,                             /* len */
 665  sharedsv_elem_mg_DELETE,       /* clear */
 666  sharedsv_elem_mg_free,         /* free */
 667  0,                             /* copy */
 668  sharedsv_elem_mg_dup           /* dup */
 669 };
 670
 671 U32
 672 sharedsv_array_mg_FETCHSIZE(pTHX_ SV *sv, MAGIC *mg)
 673 {
 674     dTHXc;
 675     shared_sv *shared = (shared_sv *) mg->mg_ptr;
 676     U32 val;
 677     SHARED_EDIT;
 678     if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
 679         val = av_len((AV*) SHAREDSvPTR(shared));
 680     }
 681     else {
 682         /* not actually defined by tie API but ... */
 683         val = HvKEYS((HV*) SHAREDSvPTR(shared));
 684     }
 685     SHARED_RELEASE;
 686     return val;
 687 }
 688
 689 int
 690 sharedsv_array_mg_CLEAR(pTHX_ SV *sv, MAGIC *mg)
 691 {
 692     dTHXc;
 693     shared_sv *shared = (shared_sv *) mg->mg_ptr;
 694     SHARED_EDIT;
 695     if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
 696         av_clear((AV*) SHAREDSvPTR(shared));
 697     }
 698     else {
 699         hv_clear((HV*) SHAREDSvPTR(shared));
 700     }
 701     SHARED_RELEASE;
 702     return 0;
 703 }
 704
 705 int
 706 sharedsv_array_mg_free(pTHX_ SV *sv, MAGIC *mg)
 707 {
 708     Perl_sharedsv_free(aTHX_ (shared_sv *) mg->mg_ptr);
 709     return 0;
 710 }
 711
 712 /*
 713  * This is called when perl is about to access an element of
 714  * the array -
 715  */
 716 int
 717 sharedsv_array_mg_copy(pTHX_ SV *sv, MAGIC* mg,
 718                        SV *nsv, const char *name, int namlen)
 719 {
 720     shared_sv *shared = (shared_sv *) mg->mg_ptr;
 721     MAGIC *nmg = sv_magicext(nsv,mg->mg_obj,
 722                             toLOWER(mg->mg_type),&sharedsv_elem_vtbl,
 723                             name, namlen);
 724     ENTER_LOCK;
 725     SvREFCNT_inc(SHAREDSvPTR(shared));
 726     LEAVE_LOCK;
 727     nmg->mg_flags |= MGf_DUP;
 728     return 1;
 729 }
 730
 731 int
 732 sharedsv_array_mg_dup(pTHX_ MAGIC *mg, CLONE_PARAMS *param)
 733 {
 734     shared_sv *shared = (shared_sv *) mg->mg_ptr;
 735     SvREFCNT_inc(SHAREDSvPTR(shared));
 736     mg->mg_flags |= MGf_DUP;
 737     return 0;
 738 }
 739
 740 MGVTBL sharedsv_array_vtbl = {
 741  0,                             /* get */
 742  0,                             /* set */
 743  sharedsv_array_mg_FETCHSIZE,   /* len */
 744  sharedsv_array_mg_CLEAR,       /* clear */
 745  sharedsv_array_mg_free,        /* free */
 746  sharedsv_array_mg_copy,        /* copy */
 747  sharedsv_array_mg_dup          /* dup */
 748 };
 749
 750 =for apidoc sharedsv_unlock
 751
 752 Recursively unlocks a shared sv.
 753
 754 =cut
 755
 756 void
 757 Perl_sharedsv_unlock(pTHX_ shared_sv* ssv)
 758 {
 759     recursive_lock_release(aTHX_ &ssv->lock);
 760 }
 761
 762 =for apidoc sharedsv_lock
 763
 764 Recursive locks on a sharedsv.
 765 Locks are dynamically scoped at the level of the first lock.
 766
 767 =cut
 768
 769 void
 770 Perl_sharedsv_lock(pTHX_ shared_sv* ssv)
 771 {
 772     if (!ssv)
 773         return;
 774     recursive_lock_acquire(aTHX_ &ssv->lock, __FILE__, __LINE__);
 775 }
 776
 777 /* handles calls from lock() builtin via PL_lockhook */
 778
 779 void
 780 Perl_sharedsv_locksv(pTHX_ SV *sv)
 781 {
 782     shared_sv* shared;
 783
 784     if(SvROK(sv))
 785         sv = SvRV(sv);
 786     shared = Perl_sharedsv_find(aTHX_ sv);
 787     if(!shared)
 788        croak("lock can only be used on shared values");
 789     Perl_sharedsv_lock(aTHX_ shared);
 790 }
 791
 792 =head1 Shared SV Functions
 793
 794 =for apidoc sharedsv_init
 795
 796 Saves a space for keeping SVs wider than an interpreter,
 797
 798 =cut
 799
 800 void
 801 Perl_sharedsv_init(pTHX)
 802 {
 803   dTHXc;
 804   /* This pair leaves us in shared context ... */
 805   PL_sharedsv_space = perl_alloc();
 806   perl_construct(PL_sharedsv_space);
 807   CALLER_CONTEXT;
 808   recursive_lock_init(aTHX_ &PL_sharedsv_lock);
 809   PL_lockhook = &Perl_sharedsv_locksv;
 810   PL_sharehook = &Perl_sharedsv_share;
 811 }
 812
 813 #endif /* USE_ITHREADS */
 814
 815 MODULE = threads::shared        PACKAGE = threads::shared::tie
 816
 817 PROTOTYPES: DISABLE
 818
 819 #ifdef USE_ITHREADS
 820
 821 void
 822 PUSH(shared_sv *shared, ...)
 823 CODE:
 824         dTHXc;
 825         int i;
 826         for(i = 1; i < items; i++) {
 827             SV* tmp = newSVsv(ST(i));
 828             shared_sv *target;
 829             ENTER_LOCK;
 830             target = Perl_sharedsv_associate(aTHX_ &tmp, Nullsv, 0);
 831             sharedsv_scalar_store(aTHX_ tmp, target);
 832             SHARED_CONTEXT;
 833             av_push((AV*) SHAREDSvPTR(shared), SHAREDSvPTR(target));
 834             SvREFCNT_inc(SHAREDSvPTR(target));
 835             SHARED_RELEASE;
 836             SvREFCNT_dec(tmp);
 837         }
 838
 839 void
 840 UNSHIFT(shared_sv *shared, ...)
 841 CODE:
 842         dTHXc;
 843         int i;
 844         ENTER_LOCK;
 845         SHARED_CONTEXT;
 846         av_unshift((AV*)SHAREDSvPTR(shared), items - 1);
 847         CALLER_CONTEXT;
 848         for(i = 1; i < items; i++) {
 849             SV* tmp = newSVsv(ST(i));
 850             shared_sv *target = Perl_sharedsv_associate(aTHX_ &tmp, Nullsv, 0);
 851             sharedsv_scalar_store(aTHX_ tmp, target);
 852             SHARED_CONTEXT;
 853             av_store((AV*) SHAREDSvPTR(shared), i - 1, SHAREDSvPTR(target));
 854             SvREFCNT_inc(SHAREDSvPTR(target));
 855             CALLER_CONTEXT;
 856             SvREFCNT_dec(tmp);
 857         }
 858         LEAVE_LOCK;
 859
 860 void
 861 POP(shared_sv *shared)
 862 CODE:
 863         dTHXc;
 864         SV* sv;
 865         ENTER_LOCK;
 866         SHARED_CONTEXT;
 867         sv = av_pop((AV*)SHAREDSvPTR(shared));
 868         CALLER_CONTEXT;
 869         ST(0) = sv_newmortal();
 870         Perl_sharedsv_associate(aTHX_ &ST(0), sv, 0);
 871         SvREFCNT_dec(sv);
 872         LEAVE_LOCK;
 873         XSRETURN(1);
 874
 875 void
 876 SHIFT(shared_sv *shared)
 877 CODE:
 878         dTHXc;
 879         SV* sv;
 880         ENTER_LOCK;
 881         SHARED_CONTEXT;
 882         sv = av_shift((AV*)SHAREDSvPTR(shared));
 883         CALLER_CONTEXT;
 884         ST(0) = sv_newmortal();
 885         Perl_sharedsv_associate(aTHX_ &ST(0), sv, 0);
 886         SvREFCNT_dec(sv);
 887         LEAVE_LOCK;
 888         XSRETURN(1);
 889
 890 void
 891 EXTEND(shared_sv *shared, IV count)
 892 CODE:
 893         dTHXc;
 894         SHARED_EDIT;
 895         av_extend((AV*)SHAREDSvPTR(shared), count);
 896         SHARED_RELEASE;
 897
 898 void
 899 STORESIZE(shared_sv *shared,IV count)
 900 CODE:
 901         dTHXc;
 902         SHARED_EDIT;
 903         av_fill((AV*) SHAREDSvPTR(shared), count);
 904         SHARED_RELEASE;
 905
 906
 907
 908
 909 void
 910 EXISTS(shared_sv *shared, SV *index)
 911 CODE:
 912         dTHXc;
 913         bool exists;
 914         SHARED_EDIT;
 915         if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
 916             exists = av_exists((AV*) SHAREDSvPTR(shared), SvIV(index));
 917         }
 918         else {
 919             STRLEN len;
 920             char *key = SvPV(index,len);
 921             exists = hv_exists((HV*) SHAREDSvPTR(shared), key, len);
 922         }
 923         SHARED_RELEASE;
 924         ST(0) = (exists) ? &PL_sv_yes : &PL_sv_no;
 925         XSRETURN(1);
 926
 927
 928 void
 929 FIRSTKEY(shared_sv *shared)
 930 CODE:
 931         dTHXc;
 932         char* key = NULL;
 933         I32 len = 0;
 934         HE* entry;
 935         ENTER_LOCK;
 936         SHARED_CONTEXT;
 937         hv_iterinit((HV*) SHAREDSvPTR(shared));
 938         entry = hv_iternext((HV*) SHAREDSvPTR(shared));
 939         if (entry) {
 940                 key = hv_iterkey(entry,&len);
 941                 CALLER_CONTEXT;
 942                 ST(0) = sv_2mortal(newSVpv(key, len));
 943         } else {
 944              CALLER_CONTEXT;
 945              ST(0) = &PL_sv_undef;
 946         }
 947         LEAVE_LOCK;
 948         XSRETURN(1);
 949
 950 void
 951 NEXTKEY(shared_sv *shared, SV *oldkey)
 952 CODE:
 953         dTHXc;
 954         char* key = NULL;
 955         I32 len = 0;
 956         HE* entry;
 957         ENTER_LOCK;
 958         SHARED_CONTEXT;
 959         entry = hv_iternext((HV*) SHAREDSvPTR(shared));
 960         if (entry) {
 961                 key = hv_iterkey(entry,&len);
 962                 CALLER_CONTEXT;
 963                 ST(0) = sv_2mortal(newSVpv(key, len));
 964         } else {
 965              CALLER_CONTEXT;
 966              ST(0) = &PL_sv_undef;
 967         }
 968         LEAVE_LOCK;
 969         XSRETURN(1);
 970
 971 MODULE = threads::shared                PACKAGE = threads::shared
 972
 973 PROTOTYPES: ENABLE
 974
 975 void
 976 _id(SV *ref)
 977         PROTOTYPE: \[$@%]
 978 CODE:
 979         shared_sv *shared;
 980         ref = SvRV(ref);
 981         if(SvROK(ref))
 982             ref = SvRV(ref);
 983         if( (shared = Perl_sharedsv_find(aTHX_ ref)) ){
 984             ST(0) = sv_2mortal(newSViv(PTR2IV(shared)));
 985             XSRETURN(1);
 986         }
 987         XSRETURN_UNDEF;
 988
 989
 990 void
 991 _refcnt(SV *ref)
 992         PROTOTYPE: \[$@%]
 993 CODE:
 994         shared_sv *shared;
 995         ref = SvRV(ref);
 996         if(SvROK(ref))
 997             ref = SvRV(ref);
 998         if( (shared = Perl_sharedsv_find(aTHX_ ref)) ){
 999           if (SHAREDSvPTR(shared)) {
1000             ST(0) = sv_2mortal(newSViv(SvREFCNT(SHAREDSvPTR(shared))));
1001             XSRETURN(1);
1002           }
1003           else {
1004              Perl_warn(aTHX_ "%" SVf " s=%p has no shared SV",ST(0),shared);
1005           }
1006         }
1007         else {
1008              Perl_warn(aTHX_ "%" SVf " is not shared",ST(0));
1009         }
1010         XSRETURN_UNDEF;
1011
1012 SV*
1013 share(SV *ref)
1014         PROTOTYPE: \[$@%]
1015         CODE:
1016         if(!SvROK(ref))
1017             Perl_croak(aTHX_ "Argument to share needs to be passed as ref");
1018         ref = SvRV(ref);
1019         if(SvROK(ref))
1020             ref = SvRV(ref);
1021         Perl_sharedsv_share(aTHX_ ref);
1022         RETVAL = newRV(ref);
1023         OUTPUT:
1024         RETVAL
1025
1026 void
1027 lock_enabled(SV *ref)
1028         PROTOTYPE: \[$@%]
1029         CODE:
1030         shared_sv* shared;
1031         if(!SvROK(ref))
1032             Perl_croak(aTHX_ "Argument to lock needs to be passed as ref");
1033         ref = SvRV(ref);
1034         if(SvROK(ref))
1035             ref = SvRV(ref);
1036         shared = Perl_sharedsv_find(aTHX_ ref);
1037         if(!shared)
1038            croak("lock can only be used on shared values");
1039         Perl_sharedsv_lock(aTHX_ shared);
1040
1041 void
1042 cond_wait_enabled(SV *ref)
1043         PROTOTYPE: \[$@%]
1044         CODE:
1045         shared_sv* shared;
1046         int locks;
1047         if(!SvROK(ref))
1048             Perl_croak(aTHX_ "Argument to cond_wait needs to be passed as ref");
1049         ref = SvRV(ref);
1050         if(SvROK(ref))
1051             ref = SvRV(ref);
1052         shared = Perl_sharedsv_find(aTHX_ ref);
1053         if(!shared)
1054             croak("cond_wait can only be used on shared values");
1055         if(shared->lock.owner != aTHX)
1056             croak("You need a lock before you can cond_wait");
1057         /* Stealing the members of the lock object worries me - NI-S */
1058         MUTEX_LOCK(&shared->lock.mutex);
1059         shared->lock.owner = NULL;
1060         locks = shared->lock.locks;
1061         shared->lock.locks = 0;
1062
1063         /* since we are releasing the lock here we need to tell other
1064         people that is ok to go ahead and use it */
1065         COND_SIGNAL(&shared->lock.cond);
1066         COND_WAIT(&shared->user_cond, &shared->lock.mutex);
1067         while(shared->lock.owner != NULL) {
1068                 COND_WAIT(&shared->lock.cond,&shared->lock.mutex);
1069         }
1070         shared->lock.owner = aTHX;
1071         shared->lock.locks = locks;
1072         MUTEX_UNLOCK(&shared->lock.mutex);
1073
1074 void
1075 cond_signal_enabled(SV *ref)
1076         PROTOTYPE: \[$@%]
1077         CODE:
1078         shared_sv* shared;
1079         if(!SvROK(ref))
1080             Perl_croak(aTHX_ "Argument to cond_signal needs to be passed as ref");
1081         ref = SvRV(ref);
1082         if(SvROK(ref))
1083             ref = SvRV(ref);
1084         shared = Perl_sharedsv_find(aTHX_ ref);
1085         if (ckWARN(WARN_THREADS) && shared->lock.owner != aTHX)
1086             Perl_warner(aTHX_ packWARN(WARN_THREADS),
1087                             "cond_signal() called on unlocked variable");
1088         if(!shared)
1089             croak("cond_signal can only be used on shared values");
1090         COND_SIGNAL(&shared->user_cond);
1091
1092 void
1093 cond_broadcast_enabled(SV *ref)
1094         PROTOTYPE: \[$@%]
1095         CODE:
1096         shared_sv* shared;
1097         if(!SvROK(ref))
1098             Perl_croak(aTHX_ "Argument to cond_broadcast needs to be passed as ref");
1099         ref = SvRV(ref);
1100         if(SvROK(ref))
1101             ref = SvRV(ref);
1102         shared = Perl_sharedsv_find(aTHX_ ref);
1103         if(!shared)
1104             croak("cond_broadcast can only be used on shared values");
1105         if (ckWARN(WARN_THREADS) && shared->lock.owner != aTHX)
1106             Perl_warner(aTHX_ packWARN(WARN_THREADS),
1107                             "cond_broadcast() called on unlocked variable");
1108         COND_BROADCAST(&shared->user_cond);
1109
1110
1111 SV*
1112 bless(SV* ref, ...);
1113         PROTOTYPE: $;$
1114         CODE:
1115         {
1116           HV* stash;
1117           shared_sv* shared;
1118           if (items == 1)
1119             stash = CopSTASH(PL_curcop);
1120           else {
1121             SV* ssv = ST(1);
1122             STRLEN len;
1123             char *ptr;
1124
1125             if (ssv && !SvGMAGICAL(ssv) && !SvAMAGIC(ssv) && SvROK(ssv))
1126               Perl_croak(aTHX_ "Attempt to bless into a reference");
1127             ptr = SvPV(ssv,len);
1128             if (ckWARN(WARN_MISC) && len == 0)
1129               Perl_warner(aTHX_ packWARN(WARN_MISC),
1130                           "Explicit blessing to '' (assuming package main)");
1131             stash = gv_stashpvn(ptr, len, TRUE);
1132           }
1133           SvREFCNT_inc(ref);
1134           (void)sv_bless(ref, stash);
1135           RETVAL = ref;
1136           shared = Perl_sharedsv_find(aTHX_ ref);
1137           if(shared) {
1138             dTHXc;
1139             ENTER_LOCK;
1140             SHARED_CONTEXT;
1141             {
1142               SV* fake_stash = newSVpv(HvNAME(stash),0);
1143               (void)sv_bless(SHAREDSvPTR(shared),(HV*)fake_stash);
1144             }
1145             CALLER_CONTEXT;
1146             LEAVE_LOCK;
1147           }
1148         }
1149         OUTPUT:
1150         RETVAL
1151
1152 #endif /* USE_ITHREADS */
1153
1154 BOOT:
1155 {
1156 #ifdef USE_ITHREADS
1157      Perl_sharedsv_init(aTHX);
1158 #endif /* USE_ITHREADS */
1159 }
1160
1161
1162