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/* You may distribute under the terms of either the GNU General Public License
* or the Artistic License (the same terms as Perl itself)
*
* (C) Paul Evans, 2021-2022 -- leonerd@leonerd.org.uk
*/
#define PERL_NO_GET_CONTEXT
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#include "object_pad.h"
static SV *unassigned_val;
#ifndef mg_freeext
# define mg_freeext(sv, how, vtbl) S_mg_freeext(aTHX_ sv, how, vtbl)
static void S_mg_freeext(pTHX_ SV *sv, int how, const MGVTBL *vtbl)
{
MAGIC *mg, *prevmg, *moremg;
assert(how == PERL_MAGIC_ext);
for(prevmg = NULL, mg = SvMAGIC(sv); mg; prevmg = mg, mg = moremg) {
moremg = mg->mg_moremagic;
if(mg->mg_type == how && mg->mg_virtual == vtbl) {
if(prevmg) {
prevmg->mg_moremagic = moremg;
}
else {
SvMAGIC_set(sv, moremg);
}
/* mg_free_struct(sv, mg) */
if(vtbl->svt_free)
vtbl->svt_free(aTHX_ sv, mg);
if(mg->mg_ptr) {
if(mg->mg_len > 0)
Safefree(mg->mg_ptr);
else if(mg->mg_len == HEf_SVKEY)
SvREFCNT_dec(MUTABLE_SV(mg->mg_ptr));
}
if(mg->mg_flags & MGf_REFCOUNTED)
SvREFCNT_dec(mg->mg_obj);
}
}
}
#endif
static int magic_get(pTHX_ SV *sv, MAGIC *mg);
static int magic_set(pTHX_ SV *sv, MAGIC *mg);
static const MGVTBL vtbl = {
.svt_get = &magic_get,
.svt_set = &magic_set,
};
static int magic_get(pTHX_ SV *sv, MAGIC *mg)
{
SV *self = mg->mg_obj;
SV *methodname = (SV *)mg->mg_ptr;
dSP;
ENTER;
SAVETMPS;
PUSHMARK(SP);
PUSHs(self);
PUTBACK;
call_method(SvPV_nolen(methodname), G_SCALAR);
SPAGAIN;
SV *value = POPs;
sv_setsv_nomg(sv, value);
FREETMPS;
LEAVE;
/* Now disarm the magic so it won't run again */
mg_freeext(sv, PERL_MAGIC_ext, &vtbl);
return 1;
}
static int magic_set(pTHX_ SV *sv, MAGIC *mg)
{
if(SvROK(sv) && SvRV(sv) == unassigned_val)
/* This is just the constructor applying the default unassigned value;
* don't disarm the magic yet
*/
return 1;
/* Now disarm the magic so it won't run again */
mg_freeext(sv, PERL_MAGIC_ext, &vtbl);
return 1;
}
static bool lazyinit_apply(pTHX_ FieldMeta *fieldmeta, SV *value, SV **attrdata_ptr, void *_funcdata)
{
mop_field_set_default_sv(fieldmeta, newRV_inc(unassigned_val));
return TRUE;
}
static void lazyinit_post_makefield(pTHX_ FieldMeta *fieldmeta, SV *attrdata, void *_funcdata, SV *field)
{
SV *weakself = newSVsv(PAD_SVl(PADIX_SELF));
sv_rvweaken(weakself);
sv_magicext(field, weakself, PERL_MAGIC_ext, &vtbl, (char *)attrdata, HEf_SVKEY);
SvREFCNT_dec(weakself);
}
static const struct FieldHookFuncs lazyinit_hooks = {
.ver = OBJECTPAD_ABIVERSION,
.flags = OBJECTPAD_FLAG_ATTR_MUST_VALUE,
.permit_hintkey = "Object::Pad::FieldAttr::LazyInit/LazyInit",
.apply = &lazyinit_apply,
.post_makefield = &lazyinit_post_makefield,
};
MODULE = Object::Pad::FieldAttr::LazyInit PACKAGE = Object::Pad::FieldAttr::LazyInit
BOOT:
register_field_attribute("LazyInit", &lazyinit_hooks, NULL);
unassigned_val = newSV(0);
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