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.
11 * Contributed by Arthur Bergman arthur@contiller.se
13 * "Hand any two wizards a piece of rope and they would instinctively pull in
14 * opposite directions."
20 #define PERL_IN_SHAREDSV_C
30 Shared SV is a structure for keeping the backend storage
36 =for apidoc sharedsv_init
38 Saves a space for keeping SVs wider than an interpreter,
39 currently only stores a pointer to the first interpreter.
45 Perl_sharedsv_init(pTHX)
47 PerlInterpreter* old_context = PERL_GET_CONTEXT;
48 PL_sharedsv_space = perl_alloc();
49 perl_construct(PL_sharedsv_space);
50 PERL_SET_CONTEXT(old_context);
51 MUTEX_INIT(&PL_sharedsv_space_mutex);
55 =for apidoc sharedsv_new
57 Allocates a new shared sv struct, you must yourself create the SV/AV/HV.
62 Perl_sharedsv_new(pTHX)
65 New(2555,ssv,1,shared_sv);
66 MUTEX_INIT(&ssv->mutex);
67 COND_INIT(&ssv->cond);
68 COND_INIT(&ssv->user_cond);
77 =for apidoc sharedsv_find
79 Tries to find if a given SV has a shared backend, either by
80 looking at magic, or by checking if it is tied again threads::shared.
86 Perl_sharedsv_find(pTHX_ SV* sv)
88 /* does all it can to find a shared_sv struct, returns NULL otherwise */
89 shared_sv* ssv = NULL;
92 {MAGIC* mg = mg_find(sv, PERL_MAGIC_ext);
94 if(strcmp(mg->mg_ptr,"threads::shared"))
96 ssv = (shared_sv*) SvIV(mg->mg_obj);
103 =for apidoc sharedsv_lock
105 Recursive locks on a sharedsv.
106 Locks are dynamicly scoped at the level of the first lock.
110 Perl_sharedsv_lock(pTHX_ shared_sv* ssv)
114 MUTEX_LOCK(&ssv->mutex);
115 if(ssv->owner && ssv->owner == my_perl) {
117 MUTEX_UNLOCK(&ssv->mutex);
121 COND_WAIT(&ssv->cond,&ssv->mutex);
123 ssv->owner = my_perl;
125 SAVEDESTRUCTOR_X(Perl_sharedsv_unlock_scope,ssv);
126 MUTEX_UNLOCK(&ssv->mutex);
130 =for apidoc sharedsv_unlock
132 Recursively unlocks a shared sv.
138 Perl_sharedsv_unlock(pTHX_ shared_sv* ssv)
140 MUTEX_LOCK(&ssv->mutex);
141 if(ssv->owner != my_perl) {
142 Perl_croak(aTHX_ "panic: Perl_sharedsv_unlock unlocking mutex that we don't own");
143 MUTEX_UNLOCK(&ssv->mutex);
147 if(--ssv->locks == 0) {
149 COND_SIGNAL(&ssv->cond);
151 MUTEX_UNLOCK(&ssv->mutex);
155 Perl_sharedsv_unlock_scope(pTHX_ shared_sv* ssv)
157 MUTEX_LOCK(&ssv->mutex);
158 if(ssv->owner != my_perl) {
159 MUTEX_UNLOCK(&ssv->mutex);
164 COND_SIGNAL(&ssv->cond);
165 MUTEX_UNLOCK(&ssv->mutex);
169 =for apidoc sharedsv_thrcnt_inc
171 Increments the threadcount of a sharedsv.
175 Perl_sharedsv_thrcnt_inc(pTHX_ shared_sv* ssv)
178 SvREFCNT_inc(ssv->sv);
183 =for apidoc sharedsv_thrcnt_dec
185 Decrements the threadcount of a shared sv. When a threads frontend is freed
186 this function should be called.
192 Perl_sharedsv_thrcnt_dec(pTHX_ shared_sv* ssv)
196 sv = SHAREDSvGET(ssv);
197 if (SvREFCNT(sv) == 1) {
198 switch (SvTYPE(sv)) {
201 Perl_sharedsv_thrcnt_dec(aTHX_ INT2PTR(shared_sv *, SvIV(SvRV(sv))));
204 SV **src_ary = AvARRAY((AV *)sv);
205 SSize_t items = AvFILLp((AV *)sv) + 1;
207 while (items-- > 0) {
209 Perl_sharedsv_thrcnt_dec(aTHX_ INT2PTR(shared_sv *, SvIV(*src_ary++)));
215 (void)hv_iterinit((HV *)sv);
216 while ((entry = hv_iternext((HV *)sv)))
217 Perl_sharedsv_thrcnt_dec(
218 aTHX_ INT2PTR(shared_sv *, SvIV(hv_iterval((HV *)sv, entry)))
224 Perl_sv_free(PL_sharedsv_space,SHAREDSvGET(ssv));
228 #endif /* USE_ITHREADS */