/* Extracted from perl-5.004/universal.c, contributed by Graham Barr */
static SV *
isa_lookup(stash, name, len, level)
HV *stash;
char *name;
int len;
int level;
{
AV* av;
GV* gv;
GV** gvp;
HV* hv = Nullhv;
if (!stash)
return &sv_undef;
if(strEQ(HvNAME(stash), name))
return &sv_yes;
if (level > 100)
croak("Recursive inheritance detected");
gvp = (GV**)hv_fetch(stash, "::ISA::CACHE::", 14, FALSE);
if (gvp && (gv = *gvp) != (GV*)&sv_undef && (hv = GvHV(gv))) {
SV* sv;
SV** svp = (SV**)hv_fetch(hv, name, len, FALSE);
if (svp && (sv = *svp) != (SV*)&sv_undef)
return sv;
}
gvp = (GV**)hv_fetch(stash,"ISA",3,FALSE);
if (gvp && (gv = *gvp) != (GV*)&sv_undef && (av = GvAV(gv))) {
if(!hv) {
gvp = (GV**)hv_fetch(stash, "::ISA::CACHE::", 14, TRUE);
gv = *gvp;
if (SvTYPE(gv) != SVt_PVGV)
gv_init(gv, stash, "::ISA::CACHE::", 14, TRUE);
hv = GvHVn(gv);
}
if(hv) {
SV** svp = AvARRAY(av);
I32 items = AvFILL(av) + 1;
while (items--) {
SV* sv = *svp++;
HV* basestash = gv_stashsv(sv, FALSE);
if (!basestash) {
if (dowarn)
warn("Can't locate package %s for @%s::ISA",
SvPVX(sv), HvNAME(stash));
continue;
}
if(&sv_yes == isa_lookup(basestash, name, len, level + 1)) {
(void)hv_store(hv,name,len,&sv_yes,0);
return &sv_yes;
}
}
(void)hv_store(hv,name,len,&sv_no,0);
}
}
return &sv_no;
}
static bool
sv_derived_from(sv, name)
SV * sv ;
char * name ;
{
SV *rv;
char *type;
HV *stash;
stash = Nullhv;
type = Nullch;
if (SvGMAGICAL(sv))
mg_get(sv) ;
if (SvROK(sv)) {
sv = SvRV(sv);
type = sv_reftype(sv,0);
if(SvOBJECT(sv))
stash = SvSTASH(sv);
}
else {
stash = gv_stashsv(sv, FALSE);
}
return (type && strEQ(type,name)) ||
(stash && isa_lookup(stash, name, strlen(name), 0) == &sv_yes)
? TRUE
: FALSE ;
}