3 * Copyright (c) 2001, Larry Wall
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.
8 * "Hand any two wizards a piece of rope and they would instinctively pull in
9 * opposite directions."
12 * Contributed by Arthur Bergman arthur@contiller.se
13 * pulled in the (an)other direction by Nick Ing-Simmons nick@ing-simmons.net
16 #define PERL_NO_GET_CONTEXT
23 #define SHAREDSvPTR(a) ((a)->sv)
26 * The shared things need an intepreter to live in ...
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 #define SHARED_CONTEXT PERL_SET_CONTEXT((aTHX = PL_sharedsv_space))
32 /* So we need a way to switch back to the caller's context... */
33 /* So we declare _another_ copy of the aTHX variable ... */
34 #define dTHXc PerlInterpreter *caller_perl = aTHX
35 /* and use it to switch back */
36 #define CALLER_CONTEXT PERL_SET_CONTEXT((aTHX = caller_perl))
39 * Only one thread at a time is allowed to mess with shared space.
45 PerlInterpreter *owner;
54 recursive_lock_t PL_sharedsv_lock; /* Mutex protecting the shared sv space */
57 recursive_lock_init(pTHX_ recursive_lock_t *lock)
59 Zero(lock,1,recursive_lock_t);
60 MUTEX_INIT(&lock->mutex);
61 COND_INIT(&lock->cond);
65 recursive_lock_release(pTHX_ recursive_lock_t *lock)
67 MUTEX_LOCK(&lock->mutex);
68 if (lock->owner != aTHX) {
69 MUTEX_UNLOCK(&lock->mutex);
72 if (--lock->locks == 0) {
74 COND_SIGNAL(&lock->cond);
77 MUTEX_UNLOCK(&lock->mutex);
81 recursive_lock_acquire(pTHX_ recursive_lock_t *lock,char *file,int line)
84 MUTEX_LOCK(&lock->mutex);
85 if (lock->owner == aTHX) {
91 Perl_warn(aTHX_ " %p waiting - owned by %p %s:%d\n",
92 aTHX, lock->owner, lock->file, lock->line);
94 COND_WAIT(&lock->cond,&lock->mutex);
103 MUTEX_UNLOCK(&lock->mutex);
104 SAVEDESTRUCTOR_X(recursive_lock_release,lock);
107 #define ENTER_LOCK STMT_START { \
109 recursive_lock_acquire(aTHX_ &PL_sharedsv_lock, __FILE__, __LINE__); \
112 #define LEAVE_LOCK LEAVE
115 /* A common idiom is to acquire access and switch in ... */
116 #define SHARED_EDIT STMT_START { \
121 /* then switch out and release access. */
122 #define SHARED_RELEASE STMT_START { \
132 Shared SV is a structure for keeping the backend storage
135 Shared-ness really only needs the SV * - the rest is for locks.
136 (Which suggests further space optimization ... )
141 SV *sv; /* The actual SV - in shared space */
142 recursive_lock_t lock;
143 perl_cond user_cond; /* For user-level conditions */
146 /* The SV in shared-space has a back-pointer to the shared_sv
147 struct associated with it PERL_MAGIC_ext.
149 The vtable used has just one entry - when the SV goes away
150 we free the memory for the above.
155 sharedsv_shared_mg_free(pTHX_ SV *sv, MAGIC *mg)
157 shared_sv *shared = (shared_sv *) mg->mg_ptr;
158 assert( aTHX == PL_sharedsv_space );
160 PerlMemShared_free(shared);
166 MGVTBL sharedsv_shared_vtbl = {
171 sharedsv_shared_mg_free, /* free */
176 /* Access to shared things is heavily based on MAGIC - in mg.h/mg.c/sv.c sense */
178 /* In any thread that has access to a shared thing there is a "proxy"
179 for it in its own space which has 'MAGIC' associated which accesses
183 MGVTBL sharedsv_scalar_vtbl; /* scalars have this vtable */
184 MGVTBL sharedsv_array_vtbl; /* hashes and arrays have this - like 'tie' */
185 MGVTBL sharedsv_elem_vtbl; /* elements of hashes and arrays have this
186 _AS WELL AS_ the scalar magic */
188 /* The sharedsv_elem_vtbl associates the element with the array/hash and
189 the sharedsv_scalar_vtbl associates it with the value
193 /* Accessor to convert threads::shared::tie objects back shared_sv * */
195 SV_to_sharedsv(pTHX_ SV *sv)
197 shared_sv *shared = 0;
200 shared = INT2PTR(shared_sv *, SvIV(SvRV(sv)));
205 =for apidoc sharedsv_find
207 Given a private side SV tries to find if the SV has a shared backend,
208 by looking for the magic.
213 Perl_sharedsv_find(pTHX_ SV *sv)
216 if (SvTYPE(sv) >= SVt_PVMG) {
220 if ((mg = mg_find(sv, PERL_MAGIC_tied))
221 && mg->mg_virtual == &sharedsv_array_vtbl) {
222 return (shared_sv *) mg->mg_ptr;
226 /* This should work for elements as well as they
227 * have scalar magic as well as their element magic
229 if ((mg = mg_find(sv, PERL_MAGIC_shared_scalar))
230 && mg->mg_virtual == &sharedsv_scalar_vtbl) {
231 return (shared_sv *) mg->mg_ptr;
236 /* Just for tidyness of API also handle tie objects */
237 if (SvROK(sv) && sv_derived_from(sv, "threads::shared::tie")) {
238 return SV_to_sharedsv(aTHX_ sv);
244 * Almost all the pain is in this routine.
249 Perl_sharedsv_associate(pTHX_ SV **psv, SV *ssv, shared_sv *data)
253 SV *sv = (psv) ? *psv : Nullsv;
255 /* If we are asked for an private ops we need a thread */
256 assert ( aTHX != PL_sharedsv_space );
258 /* To avoid need for recursive locks require caller to hold lock */
259 assert ( PL_sharedsv_lock.owner == aTHX );
261 /* First try and get existing global data structure */
263 /* Try shared SV as 1st choice */
264 if (!data && ssv && SvTYPE(ssv) >= SVt_PVMG) {
265 if (mg = mg_find(ssv, PERL_MAGIC_ext)) {
266 data = (shared_sv *) mg->mg_ptr;
270 /* Next see if private SV is associated with something */
272 data = Perl_sharedsv_find(aTHX_ sv);
275 /* If neither of those then create a new one */
280 data = PerlMemShared_malloc(sizeof(shared_sv));
281 Zero(data,1,shared_sv);
282 SHAREDSvPTR(data) = ssv;
283 /* Tag shared side SV with data pointer */
284 sv_magicext(ssv, ssv, PERL_MAGIC_ext, &sharedsv_shared_vtbl,
286 recursive_lock_init(aTHX_ &data->lock);
287 COND_INIT(&data->user_cond);
292 ssv = SHAREDSvPTR(data);
293 if (!SHAREDSvPTR(data))
294 SHAREDSvPTR(data) = ssv;
296 /* If we know type upgrade shared side SV */
297 if (sv && SvTYPE(ssv) < SvTYPE(sv)) {
299 sv_upgrade(ssv, SvTYPE(*psv));
303 /* Now if requested allocate private SV */
305 *psv = sv = newSV(0);
308 /* Finally if private SV exists check and add magic */
311 if (SvTYPE(sv) < SvTYPE(ssv)) {
312 sv_upgrade(sv, SvTYPE(ssv));
317 if (!(mg = mg_find(sv, PERL_MAGIC_tied))
318 || mg->mg_virtual != &sharedsv_array_vtbl
319 || (shared_sv *) mg->mg_ptr != data) {
321 sv_setref_iv(obj, "threads::shared::tie",PTR2IV(data));
323 sv_unmagic(sv, PERL_MAGIC_tied);
325 mg = sv_magicext(sv, obj, PERL_MAGIC_tied, &sharedsv_array_vtbl,
327 mg->mg_flags |= (MGf_COPY|MGf_DUP);
334 if ((SvTYPE(sv) < SVt_PVMG)
335 || !(mg = mg_find(sv, PERL_MAGIC_shared_scalar))
336 || mg->mg_virtual != &sharedsv_scalar_vtbl
337 || (shared_sv *) mg->mg_ptr != data) {
339 sv_unmagic(sv, PERL_MAGIC_shared_scalar);
341 mg = sv_magicext(sv, Nullsv, PERL_MAGIC_shared_scalar,
342 &sharedsv_scalar_vtbl, (char *)data, 0);
343 mg->mg_flags |= (MGf_COPY|MGf_DUP);
348 assert ( Perl_sharedsv_find(aTHX_ *psv) == data );
354 Perl_sharedsv_free(pTHX_ shared_sv *shared)
359 SvREFCNT_dec(SHAREDSvPTR(shared));
365 Perl_sharedsv_share(pTHX_ SV *sv)
369 Perl_croak(aTHX_ "Cannot share globs yet");
373 Perl_croak(aTHX_ "Cannot share subs yet");
378 Perl_sharedsv_associate(aTHX_ &sv, 0, 0);
385 /* MAGIC (in mg.h sense) hooks */
388 sharedsv_scalar_mg_get(pTHX_ SV *sv, MAGIC *mg)
390 shared_sv *shared = (shared_sv *) mg->mg_ptr;
394 if (SHAREDSvPTR(shared)) {
395 if (SvROK(SHAREDSvPTR(shared))) {
397 Perl_sharedsv_associate(aTHX_ &obj, SvRV(SHAREDSvPTR(shared)), NULL);
398 sv_setsv_nomg(sv, &PL_sv_undef);
403 sv_setsv_nomg(sv, SHAREDSvPTR(shared));
411 sharedsv_scalar_store(pTHX_ SV *sv, shared_sv *shared)
416 shared_sv* target = Perl_sharedsv_find(aTHX_ SvRV(sv));
420 tmp = newRV(SHAREDSvPTR(target));
421 sv_setsv_nomg(SHAREDSvPTR(shared), tmp);
432 sv_setsv_nomg(SHAREDSvPTR(shared), sv);
436 Perl_croak(aTHX_ "Invalid value for shared scalar");
441 sharedsv_scalar_mg_set(pTHX_ SV *sv, MAGIC *mg)
445 /* We call associate to potentially upgrade shared side SV */
446 shared = Perl_sharedsv_associate(aTHX_ &sv, Nullsv, (shared_sv *) mg->mg_ptr);
448 sharedsv_scalar_store(aTHX_ sv, shared);
454 sharedsv_scalar_mg_free(pTHX_ SV *sv, MAGIC *mg)
456 shared_sv *shared = (shared_sv *) mg->mg_ptr;
458 assert (SvREFCNT(SHAREDSvPTR(shared)) < 1000);
460 Perl_sharedsv_free(aTHX_ shared);
465 sharedsv_scalar_mg_clear(pTHX_ SV *sv, MAGIC *mg)
471 * Called during cloning of new threads
474 sharedsv_scalar_mg_dup(pTHX_ MAGIC *mg, CLONE_PARAMS *param)
476 shared_sv *shared = (shared_sv *) mg->mg_ptr;
478 SvREFCNT_inc(SHAREDSvPTR(shared));
483 MGVTBL sharedsv_scalar_vtbl = {
484 sharedsv_scalar_mg_get, /* get */
485 sharedsv_scalar_mg_set, /* set */
487 sharedsv_scalar_mg_clear, /* clear */
488 sharedsv_scalar_mg_free, /* free */
490 sharedsv_scalar_mg_dup /* dup */
493 /* Now the arrays/hashes stuff */
495 sharedsv_elem_mg_FETCH(pTHX_ SV *sv, MAGIC *mg)
498 shared_sv *shared = SV_to_sharedsv(aTHX_ mg->mg_obj);
499 shared_sv *target = Perl_sharedsv_find(aTHX_ sv);
503 assert ( SHAREDSvPTR(shared) );
507 if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
508 assert ( mg->mg_ptr == 0 );
510 svp = av_fetch((AV*) SHAREDSvPTR(shared), mg->mg_len, 0);
513 char *key = mg->mg_ptr;
514 STRLEN len = mg->mg_len;
515 assert ( mg->mg_ptr != 0 );
516 if (mg->mg_len == HEf_SVKEY) {
517 key = SvPV((SV *) mg->mg_ptr, len);
520 svp = hv_fetch((HV*) SHAREDSvPTR(shared), key, len, 0);
524 /* Exists in the array */
525 target = Perl_sharedsv_associate(aTHX_ &sv, *svp, target);
529 /* Not in the array */
530 sv_setsv(sv, &PL_sv_undef);
537 sharedsv_elem_mg_STORE(pTHX_ SV *sv, MAGIC *mg)
540 shared_sv *shared = SV_to_sharedsv(aTHX_ mg->mg_obj);
543 /* Theory - SV itself is magically shared - and we have ordered the
544 magic such that by the time we get here it has been stored
545 to its shared counterpart
549 assert(SHAREDSvPTR(shared));
550 if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
551 assert ( mg->mg_ptr == 0 );
553 svp = av_fetch((AV*) SHAREDSvPTR(shared), mg->mg_len, 1);
556 char *key = mg->mg_ptr;
557 STRLEN len = mg->mg_len;
558 assert ( mg->mg_ptr != 0 );
559 if (mg->mg_len == HEf_SVKEY)
560 key = SvPV((SV *) mg->mg_ptr, len);
562 svp = hv_fetch((HV*) SHAREDSvPTR(shared), key, len, 1);
565 target = Perl_sharedsv_associate(aTHX_ &sv, *svp, 0);
566 sharedsv_scalar_store(aTHX_ sv, target);
572 sharedsv_elem_mg_DELETE(pTHX_ SV *sv, MAGIC *mg)
575 shared_sv *shared = SV_to_sharedsv(aTHX_ mg->mg_obj);
577 sharedsv_elem_mg_FETCH(aTHX_ sv, mg);
578 if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
580 av_delete((AV*) SHAREDSvPTR(shared), mg->mg_len, G_DISCARD);
583 char *key = mg->mg_ptr;
584 STRLEN len = mg->mg_len;
585 assert ( mg->mg_ptr != 0 );
586 if (mg->mg_len == HEf_SVKEY)
587 key = SvPV((SV *) mg->mg_ptr, len);
589 hv_delete((HV*) SHAREDSvPTR(shared), key, len, G_DISCARD);
597 sharedsv_elem_mg_free(pTHX_ SV *sv, MAGIC *mg)
599 Perl_sharedsv_free(aTHX_ SV_to_sharedsv(aTHX_ mg->mg_obj));
604 sharedsv_elem_mg_dup(pTHX_ MAGIC *mg, CLONE_PARAMS *param)
606 shared_sv *shared = SV_to_sharedsv(aTHX_ mg->mg_obj);
607 SvREFCNT_inc(SHAREDSvPTR(shared));
608 mg->mg_flags |= MGf_DUP;
612 MGVTBL sharedsv_elem_vtbl = {
613 sharedsv_elem_mg_FETCH, /* get */
614 sharedsv_elem_mg_STORE, /* set */
616 sharedsv_elem_mg_DELETE, /* clear */
617 sharedsv_elem_mg_free, /* free */
619 sharedsv_elem_mg_dup /* dup */
623 sharedsv_array_mg_FETCHSIZE(pTHX_ SV *sv, MAGIC *mg)
626 shared_sv *shared = (shared_sv *) mg->mg_ptr;
629 if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
630 val = av_len((AV*) SHAREDSvPTR(shared));
633 /* not actually defined by tie API but ... */
634 val = HvKEYS((HV*) SHAREDSvPTR(shared));
641 sharedsv_array_mg_CLEAR(pTHX_ SV *sv, MAGIC *mg)
644 shared_sv *shared = (shared_sv *) mg->mg_ptr;
646 if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
647 av_clear((AV*) SHAREDSvPTR(shared));
650 hv_clear((HV*) SHAREDSvPTR(shared));
657 sharedsv_array_mg_free(pTHX_ SV *sv, MAGIC *mg)
659 Perl_sharedsv_free(aTHX_ (shared_sv *) mg->mg_ptr);
664 * This is called when perl is about to access an element of
668 sharedsv_array_mg_copy(pTHX_ SV *sv, MAGIC* mg,
669 SV *nsv, const char *name, int namlen)
671 shared_sv *shared = (shared_sv *) mg->mg_ptr;
672 MAGIC *nmg = sv_magicext(nsv,mg->mg_obj,
673 toLOWER(mg->mg_type),&sharedsv_elem_vtbl,
675 SvREFCNT_inc(SHAREDSvPTR(shared));
676 nmg->mg_flags |= MGf_DUP;
681 sharedsv_array_mg_dup(pTHX_ MAGIC *mg, CLONE_PARAMS *param)
683 shared_sv *shared = (shared_sv *) mg->mg_ptr;
684 SvREFCNT_inc(SHAREDSvPTR(shared));
685 mg->mg_flags |= MGf_DUP;
689 MGVTBL sharedsv_array_vtbl = {
692 sharedsv_array_mg_FETCHSIZE, /* len */
693 sharedsv_array_mg_CLEAR, /* clear */
694 sharedsv_array_mg_free, /* free */
695 sharedsv_array_mg_copy, /* copy */
696 sharedsv_array_mg_dup /* dup */
699 =for apidoc sharedsv_unlock
701 Recursively unlocks a shared sv.
706 Perl_sharedsv_unlock(pTHX_ shared_sv* ssv)
708 recursive_lock_release(aTHX_ &ssv->lock);
711 =for apidoc sharedsv_lock
713 Recursive locks on a sharedsv.
714 Locks are dynamically scoped at the level of the first lock.
719 Perl_sharedsv_lock(pTHX_ shared_sv* ssv)
723 recursive_lock_acquire(aTHX_ &ssv->lock, __FILE__, __LINE__);
727 Perl_sharedsv_locksv(pTHX_ SV *sv)
729 Perl_sharedsv_lock(aTHX_ Perl_sharedsv_find(aTHX_ sv));
732 =head1 Shared SV Functions
734 =for apidoc sharedsv_init
736 Saves a space for keeping SVs wider than an interpreter,
737 currently only stores a pointer to the first interpreter.
742 Perl_sharedsv_init(pTHX)
745 /* This pair leaves us in shared context ... */
746 PL_sharedsv_space = perl_alloc();
747 perl_construct(PL_sharedsv_space);
749 recursive_lock_init(aTHX_ &PL_sharedsv_lock);
750 PL_lockhook = &Perl_sharedsv_locksv;
751 PL_sharehook = &Perl_sharedsv_share;
754 #endif /* USE_ITHREADS */
756 MODULE = threads::shared PACKAGE = threads::shared::tie
763 PUSH(shared_sv *shared, ...)
767 for(i = 1; i < items; i++) {
768 SV* tmp = newSVsv(ST(i));
771 target = Perl_sharedsv_associate(aTHX_ &tmp, Nullsv, 0);
772 sharedsv_scalar_store(aTHX_ tmp, target);
774 av_push((AV*) SHAREDSvPTR(shared), SHAREDSvPTR(target));
780 UNSHIFT(shared_sv *shared, ...)
786 av_unshift((AV*)SHAREDSvPTR(shared), items - 1);
788 for(i = 1; i < items; i++) {
789 SV* tmp = newSVsv(ST(i));
790 shared_sv *target = Perl_sharedsv_associate(aTHX_ &tmp, Nullsv, 0);
791 sharedsv_scalar_store(aTHX_ tmp, target);
793 av_store((AV*) SHAREDSvPTR(shared), i - 1, SHAREDSvPTR(target));
800 POP(shared_sv *shared)
806 sv = av_pop((AV*)SHAREDSvPTR(shared));
809 Perl_sharedsv_associate(aTHX_ &ST(0), sv, 0);
814 SHIFT(shared_sv *shared)
820 sv = av_shift((AV*)SHAREDSvPTR(shared));
823 Perl_sharedsv_associate(aTHX_ &ST(0), sv, 0);
828 EXTEND(shared_sv *shared, IV count)
832 av_extend((AV*)SHAREDSvPTR(shared), count);
836 STORESIZE(shared_sv *shared,IV count)
840 av_fill((AV*) SHAREDSvPTR(shared), count);
847 EXISTS(shared_sv *shared, SV *index)
852 if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
853 exists = av_exists((AV*) SHAREDSvPTR(shared), SvIV(index));
857 char *key = SvPV(index,len);
858 exists = hv_exists((HV*) SHAREDSvPTR(shared), key, len);
861 ST(0) = (exists) ? &PL_sv_yes : &PL_sv_no;
866 FIRSTKEY(shared_sv *shared)
874 hv_iterinit((HV*) SHAREDSvPTR(shared));
875 entry = hv_iternext((HV*) SHAREDSvPTR(shared));
877 key = hv_iterkey(entry,&len);
879 ST(0) = sv_2mortal(newSVpv(key, len));
882 ST(0) = &PL_sv_undef;
888 NEXTKEY(shared_sv *shared, SV *oldkey)
896 entry = hv_iternext((HV*) SHAREDSvPTR(shared));
898 key = hv_iterkey(entry,&len);
900 ST(0) = sv_2mortal(newSVpv(key, len));
903 ST(0) = &PL_sv_undef;
908 MODULE = threads::shared PACKAGE = threads::shared
919 if (shared = Perl_sharedsv_find(aTHX_ ref)) {
920 ST(0) = sv_2mortal(newSViv(PTR2IV(shared)));
933 if (shared = Perl_sharedsv_find(aTHX_ ref)) {
934 if (SHAREDSvPTR(shared)) {
935 ST(0) = sv_2mortal(newSViv(SvREFCNT(SHAREDSvPTR(shared))));
939 Perl_warn(aTHX_ "%_ s=%p has no shared SV",ST(0),shared);
943 Perl_warn(aTHX_ "%_ is not shared",ST(0));
953 Perl_sharedsv_share(aTHX, ref);
956 lock_enabled(SV *ref)
962 shared = Perl_sharedsv_find(aTHX, ref);
964 croak("lock can only be used on shared values");
965 Perl_sharedsv_lock(aTHX_ shared);
968 cond_wait_enabled(SV *ref)
975 shared = Perl_sharedsv_find(aTHX_ ref);
977 croak("cond_wait can only be used on shared values");
978 if(shared->lock.owner != aTHX)
979 croak("You need a lock before you can cond_wait");
980 /* Stealing the members of the lock object worries me - NI-S */
981 MUTEX_LOCK(&shared->lock.mutex);
982 shared->lock.owner = NULL;
983 locks = shared->lock.locks;
984 shared->lock.locks = 0;
986 /* since we are releasing the lock here we need to tell other
987 people that is ok to go ahead and use it */
988 COND_SIGNAL(&shared->lock.cond);
989 COND_WAIT(&shared->user_cond, &shared->lock.mutex);
990 while(shared->lock.owner != NULL) {
991 COND_WAIT(&shared->lock.cond,&shared->lock.mutex);
993 shared->lock.owner = aTHX;
994 shared->lock.locks = locks;
995 MUTEX_UNLOCK(&shared->lock.mutex);
998 cond_signal_enabled(SV *ref)
1004 shared = Perl_sharedsv_find(aTHX_ ref);
1006 croak("cond_signal can only be used on shared values");
1007 COND_SIGNAL(&shared->user_cond);
1010 cond_broadcast_enabled(SV *ref)
1016 shared = Perl_sharedsv_find(aTHX_ ref);
1018 croak("cond_broadcast can only be used on shared values");
1019 COND_BROADCAST(&shared->user_cond);
1021 #endif /* USE_ITHREADS */
1026 Perl_sharedsv_init(aTHX);
1027 #endif /* USE_ITHREADS */