STATIC void
S_mro_gather_and_rename(pTHX_ HV * const stashes, HV * const seen_stashes,
HV *stash, HV *oldstash, SV *namesv)
{
XPVHV* xhv;
HE *entry;
I32 riter = -1;
I32 items = 0;
const bool stash_had_name = stash && HvENAME(stash);
bool fetched_isarev = FALSE;
HV *seen = NULL;
HV *isarev = NULL;
SV **svp = NULL;
PERL_ARGS_ASSERT_MRO_GATHER_AND_RENAME;
/* We use the seen_stashes hash to keep track of which packages have
been encountered so far. This must be separate from the main list of
stashes, as we need to distinguish between stashes being assigned
and stashes being replaced/deleted. (A nested stash can be on both
sides of an assignment. We cannot simply skip iterating through a
stash on the right if we have seen it on the left, as it will not
get its ename assigned to it.)
To avoid allocating extra SVs, instead of a bitfield we can make
bizarre use of immortals:
&PL_sv_undef: seen on the left (oldstash)
&PL_sv_no : seen on the right (stash)
&PL_sv_yes : seen on both sides
*/
if(oldstash) {
/* Add to the big list. */
struct mro_meta * meta;
HE * const entry
= (HE *)
hv_common(
seen_stashes, NULL, (const char *)&oldstash, sizeof(HV *), 0,
HV_FETCH_LVALUE|HV_FETCH_EMPTY_HE, NULL, 0
);
if(HeVAL(entry) == &PL_sv_undef || HeVAL(entry) == &PL_sv_yes) {
oldstash = NULL;
goto check_stash;
}
HeVAL(entry)
= HeVAL(entry) == &PL_sv_no ? &PL_sv_yes : &PL_sv_undef;
meta = HvMROMETA(oldstash);
(void)
hv_store(
stashes, (const char *)&oldstash, sizeof(HV *),
meta->isa
? SvREFCNT_inc_simple_NN((SV *)meta->isa)
: &PL_sv_yes,
0
);
CLEAR_LINEAR(meta);
/* Update the effective name. */
if(HvENAME_get(oldstash)) {
const HEK * const enamehek = HvENAME_HEK(oldstash);
if(SvTYPE(namesv) == SVt_PVAV) {
items = AvFILLp((AV *)namesv) + 1;
svp = AvARRAY((AV *)namesv);
}
else {
items = 1;
svp = &namesv;
}
while (items--) {
const U32 name_utf8 = SvUTF8(*svp);
STRLEN len;
const char *name = SvPVx_const(*svp, len);
if(PL_stashcache) {
DEBUG_o(Perl_deb(aTHX_ "mro_gather_and_rename clearing PL_stashcache for '%"SVf"'\n",
SVfARG(*svp)));
(void)hv_delete(PL_stashcache, name, name_utf8 ? -(I32)len : (I32)len, G_DISCARD);
}
++svp;
hv_ename_delete(oldstash, name, len, name_utf8);
if (!fetched_isarev) {
/* If the name deletion caused a name change, then we
* are not going to call mro_isa_changed_in with this
* name (and not at all if it has become anonymous) so
* we need to delete old isarev entries here, both
* those in the superclasses and this class's own list
* of subclasses. We simply delete the latter from
* PL_isarev, since we still need it. hv_delete morti-
* fies it for us, so sv_2mortal is not necessary. */
if(HvENAME_HEK(oldstash) != enamehek) {
if(meta->isa && HvARRAY(meta->isa))
mro_clean_isarev(meta->isa, name, len, 0, 0,
name_utf8 ? HVhek_UTF8 : 0);
isarev = (HV *)hv_delete(PL_isarev, name,
name_utf8 ? -(I32)len : (I32)len, 0);
fetched_isarev=TRUE;
}
}
}
}
}
check_stash:
if(stash) {
if(SvTYPE(namesv) == SVt_PVAV) {
items = AvFILLp((AV *)namesv) + 1;
svp = AvARRAY((AV *)namesv);
}
else {
items = 1;
svp = &namesv;
}
while (items--) {
const U32 name_utf8 = SvUTF8(*svp);
STRLEN len;
const char *name = SvPVx_const(*svp++, len);
hv_ename_add(stash, name, len, name_utf8);
}
/* Add it to the big list if it needs
* mro_isa_changed_in called on it. That happens if it was
* detached from the symbol table (so it had no HvENAME) before
* being assigned to the spot named by the 'name' variable, because
* its cached isa linearisation is now stale (the effective name
* having changed), and subclasses will then use that cache when
* mro_package_moved calls mro_isa_changed_in. (See
* [perl #77358].)
*
* If it did have a name, then its previous name is still
* used in isa caches, and there is no need for
* mro_package_moved to call mro_isa_changed_in.
*/
entry
= (HE *)
hv_common(
seen_stashes, NULL, (const char *)&stash, sizeof(HV *), 0,
HV_FETCH_LVALUE|HV_FETCH_EMPTY_HE, NULL, 0
);
if(HeVAL(entry) == &PL_sv_yes || HeVAL(entry) == &PL_sv_no)
stash = NULL;
else {
HeVAL(entry)
= HeVAL(entry) == &PL_sv_undef ? &PL_sv_yes : &PL_sv_no;
if(!stash_had_name)
{
struct mro_meta * const meta = HvMROMETA(stash);
(void)
hv_store(
stashes, (const char *)&stash, sizeof(HV *),
meta->isa
? SvREFCNT_inc_simple_NN((SV *)meta->isa)
: &PL_sv_yes,
0
);
CLEAR_LINEAR(meta);
}
}
}
if(!stash && !oldstash)
/* Both stashes have been encountered already. */
return;
/* Add all the subclasses to the big list. */
if(!fetched_isarev) {
/* If oldstash is not null, then we can use its HvENAME to look up
the isarev hash, since all its subclasses will be listed there.
It will always have an HvENAME. It the HvENAME was removed
above, then fetch_isarev will be true, and this code will not be
reached.
If oldstash is null, then this is an empty spot with no stash in
it, so subclasses could be listed in isarev hashes belonging to
any of the names, so we have to check all of them.
*/
assert(!oldstash || HvENAME(oldstash));
if (oldstash) {
/* Extra variable to avoid a compiler warning */
const HEK * const hvename = HvENAME_HEK(oldstash);
fetched_isarev = TRUE;
svp = hv_fetchhek(PL_isarev, hvename, 0);
if (svp) isarev = MUTABLE_HV(*svp);
}
else if(SvTYPE(namesv) == SVt_PVAV) {
items = AvFILLp((AV *)namesv) + 1;
svp = AvARRAY((AV *)namesv);
}
else {
items = 1;
svp = &namesv;
}
}
if(
isarev || !fetched_isarev
) {
while (fetched_isarev || items--) {
HE *iter;
if (!fetched_isarev) {
HE * const he = hv_fetch_ent(PL_isarev, *svp++, 0, 0);
if (!he || !(isarev = MUTABLE_HV(HeVAL(he)))) continue;
}
hv_iterinit(isarev);
while((iter = hv_iternext(isarev))) {
HV* revstash = gv_stashsv(hv_iterkeysv(iter), 0);
struct mro_meta * meta;
if(!revstash) continue;
meta = HvMROMETA(revstash);
(void)
hv_store(
stashes, (const char *)&revstash, sizeof(HV *),
meta->isa
? SvREFCNT_inc_simple_NN((SV *)meta->isa)
: &PL_sv_yes,
0
);
CLEAR_LINEAR(meta);
}
if (fetched_isarev) break;
}
}
/* This is partly based on code in hv_iternext_flags. We are not call-
ing that here, as we want to avoid resetting the hash iterator. */
/* Skip the entire loop if the hash is empty. */
if(oldstash && HvUSEDKEYS(oldstash)) {
xhv = (XPVHV*)SvANY(oldstash);
seen = (HV *) sv_2mortal((SV *)newHV());
/* Iterate through entries in the oldstash, adding them to the
list, meanwhile doing the equivalent of $seen{$key} = 1.
*/
while (++riter <= (I32)xhv->xhv_max) {
entry = (HvARRAY(oldstash))[riter];
/* Iterate through the entries in this list */
for(; entry; entry = HeNEXT(entry)) {
const char* key;
I32 len;
/* If this entry is not a glob, ignore it.
Try the next. */
if (!isGV(HeVAL(entry))) continue;
key = hv_iterkey(entry, &len);
if ((len > 1 && key[len-2] == ':' && key[len-1] == ':')
|| (len == 1 && key[0] == ':')) {
HV * const oldsubstash = GvHV(HeVAL(entry));
SV ** const stashentry
= stash ? hv_fetch(stash, key, HeUTF8(entry) ? -(I32)len : (I32)len, 0) : NULL;
HV *substash = NULL;
/* Avoid main::main::main::... */
if(oldsubstash == oldstash) continue;
if(
(
stashentry && *stashentry && isGV(*stashentry)
&& (substash = GvHV(*stashentry))
)
|| (oldsubstash && HvENAME_get(oldsubstash))
)
{
/* Add :: and the key (minus the trailing ::)
to each name. */
SV *subname;
if(SvTYPE(namesv) == SVt_PVAV) {
SV *aname;
items = AvFILLp((AV *)namesv) + 1;
svp = AvARRAY((AV *)namesv);
subname = sv_2mortal((SV *)newAV());
while (items--) {
aname = newSVsv(*svp++);
if (len == 1)
sv_catpvs(aname, ":");
else {
sv_catpvs(aname, "::");
sv_catpvn_flags(
aname, key, len-2,
HeUTF8(entry)
? SV_CATUTF8 : SV_CATBYTES
);
}
av_push((AV *)subname, aname);
}
}
else {
subname = sv_2mortal(newSVsv(namesv));
if (len == 1) sv_catpvs(subname, ":");
else {
sv_catpvs(subname, "::");
sv_catpvn_flags(
subname, key, len-2,
HeUTF8(entry) ? SV_CATUTF8 : SV_CATBYTES
);
}
}
mro_gather_and_rename(
stashes, seen_stashes,
substash, oldsubstash, subname
);
}
(void)hv_store(seen, key, HeUTF8(entry) ? -(I32)len : (I32)len, &PL_sv_yes, 0);
}
}
}
}
/* Skip the entire loop if the hash is empty. */
if (stash && HvUSEDKEYS(stash)) {
xhv = (XPVHV*)SvANY(stash);
riter = -1;
/* Iterate through the new stash, skipping $seen{$key} items,
calling mro_gather_and_rename(stashes,seen,entry,NULL, ...). */
while (++riter <= (I32)xhv->xhv_max) {
entry = (HvARRAY(stash))[riter];
/* Iterate through the entries in this list */
for(; entry; entry = HeNEXT(entry)) {
const char* key;
I32 len;
/* If this entry is not a glob, ignore it.
Try the next. */
if (!isGV(HeVAL(entry))) continue;
key = hv_iterkey(entry, &len);
if ((len > 1 && key[len-2] == ':' && key[len-1] == ':')
|| (len == 1 && key[0] == ':')) {
HV *substash;
/* If this entry was seen when we iterated through the
oldstash, skip it. */
if(seen && hv_exists(seen, key, HeUTF8(entry) ? -(I32)len : (I32)len)) continue;
/* We get here only if this stash has no corresponding
entry in the stash being replaced. */
substash = GvHV(HeVAL(entry));
if(substash) {
SV *subname;
/* Avoid checking main::main::main::... */
if(substash == stash) continue;
/* Add :: and the key (minus the trailing ::)
to each name. */
if(SvTYPE(namesv) == SVt_PVAV) {
SV *aname;
items = AvFILLp((AV *)namesv) + 1;
svp = AvARRAY((AV *)namesv);
subname = sv_2mortal((SV *)newAV());
while (items--) {
aname = newSVsv(*svp++);
if (len == 1)
sv_catpvs(aname, ":");
else {
sv_catpvs(aname, "::");
sv_catpvn_flags(
aname, key, len-2,
HeUTF8(entry)
? SV_CATUTF8 : SV_CATBYTES
);
}
av_push((AV *)subname, aname);
}
}
else {
subname = sv_2mortal(newSVsv(namesv));
if (len == 1) sv_catpvs(subname, ":");
else {
sv_catpvs(subname, "::");
sv_catpvn_flags(
subname, key, len-2,
HeUTF8(entry) ? SV_CATUTF8 : SV_CATBYTES
);
}
}
mro_gather_and_rename(
stashes, seen_stashes,
substash, NULL, subname
);
}
}
}
}
}
}
OP *
Perl_scalarvoid(pTHX_ OP *o)
{
dVAR;
OP *kid;
const char* useless = NULL;
SV* sv;
U8 want;
PERL_ARGS_ASSERT_SCALARVOID;
/* trailing mad null ops don't count as "there" for void processing */
if (PL_madskills &&
o->op_type != OP_NULL &&
o->op_sibling &&
o->op_sibling->op_type == OP_NULL)
{
OP *sib;
for (sib = o->op_sibling;
sib && sib->op_type == OP_NULL;
sib = sib->op_sibling) ;
if (!sib)
return o;
}
if (o->op_type == OP_NEXTSTATE
|| o->op_type == OP_DBSTATE
|| (o->op_type == OP_NULL && (o->op_targ == OP_NEXTSTATE
|| o->op_targ == OP_DBSTATE)))
PL_curcop = (COP*)o; /* for warning below */
/* assumes no premature commitment */
want = o->op_flags & OPf_WANT;
if ((want && want != OPf_WANT_SCALAR)
|| (PL_parser && PL_parser->error_count)
|| o->op_type == OP_RETURN)
{
return o;
}
if ((o->op_flags & OPf_TARGET_MY)
&& (PL_opargs[o->op_type] & OA_TARGLEX))/* OPp share the meaning */
{
return scalar(o); /* As if inside SASSIGN */
}
o->op_flags = (o->op_flags & ~OPf_WANT) | OPf_WANT_VOID;
switch (o->op_type) {
default:
if (!(PL_opargs[o->op_type] & OA_FOLDCONST))
break;
/* FALL THROUGH */
case OP_REPEAT:
if (o->op_flags & OPf_STACKED)
break;
goto func_ops;
case OP_SUBSTR:
case OP_VEC:
if (o->op_private == 4)
break;
/* FALL THROUGH */
case OP_GVSV:
case OP_GV:
case OP_PADSV:
case OP_REF:
case OP_SREFGEN:
case OP_DEFINED:
case OP_HEX:
case OP_OCT:
case OP_LENGTH:
case OP_INDEX:
case OP_RINDEX:
case OP_SPRINTF:
case OP_ASLICE:
case OP_HSLICE:
case OP_UNPACK:
case OP_PACK:
case OP_JOIN:
case OP_LSLICE:
case OP_SORT:
case OP_REVERSE:
case OP_RANGE:
case OP_CALLER:
case OP_FILENO:
case OP_EOF:
case OP_TELL:
case OP_GETSOCKNAME:
case OP_GETPEERNAME:
case OP_READLINK:
case OP_TELLDIR:
case OP_GETPPID:
case OP_GETPGRP:
case OP_GETPRIORITY:
case OP_TIME:
case OP_TMS:
case OP_LOCALTIME:
case OP_GMTIME:
case OP_GHBYNAME:
case OP_GHBYADDR:
case OP_GHOSTENT:
case OP_GNBYNAME:
case OP_GNBYADDR:
case OP_GNETENT:
case OP_GPBYNAME:
case OP_GPBYNUMBER:
case OP_GPROTOENT:
case OP_GSBYNAME:
case OP_GSBYPORT:
case OP_GSERVENT:
case OP_GPWNAM:
case OP_GPWUID:
case OP_GGRNAM:
case OP_GGRGID:
case OP_GETLOGIN:
case OP_PROTOTYPE:
func_ops:
if (!(o->op_private & (OPpLVAL_INTRO|OPpOUR_INTRO)))
/* Otherwise it's "Useless use of grep iterator" */
useless = OP_DESC(o);
break;
case OP_HELEM:
case OP_AELEM:
case OP_AELEMFAST:
if (!(o->op_private & (OPpLVAL_INTRO|OPpOUR_INTRO|OPpELEM_ADD)))
/* Otherwise it's "Useless use of grep iterator" */
useless = OP_DESC(o);
break;
case OP_ANONARRAY:
case OP_ANONHASH:
useless = OP_DESC(o);
break;
case OP_NOT:
kid = cUNOPo->op_first;
if (kid->op_type != OP_MATCH && kid->op_type != OP_SUBST) {
goto func_ops;
}
useless = "negative pattern binding (!~)";
break;
case OP_RV2GV:
case OP_RV2SV:
case OP_RV2AV:
case OP_RV2HV:
if (!(o->op_private & (OPpLVAL_INTRO|OPpOUR_INTRO)) &&
(!o->op_sibling || o->op_sibling->op_type != OP_READLINE))
useless = "a variable";
break;
case OP_CONST:
sv = cSVOPo_sv;
if (cSVOPo->op_private & OPpCONST_STRICT)
Perl_croak_at(aTHX_
o->op_location,
"Bareword \"%"SVf"\" not allowed while \"strict subs\" in use",
SVfARG(cSVOPo_sv));
else {
if (ckWARN(WARN_VOID)) {
useless = "a constant";
/* don't warn on optimised away booleans, eg
* use constant Foo, 5; Foo || print; */
if (cSVOPo->op_private & OPpCONST_SHORTCIRCUIT)
useless = NULL;
/* the constants 0 and 1 are permitted as they are
conventionally used as dummies in constructs like
1 while some_condition_with_side_effects; */
else if (SvNIOK(sv) && (SvNV(sv) == 0.0 || SvNV(sv) == 1.0))
useless = NULL;
else if (SvPOK(sv)) {
/* perl4's way of mixing documentation and code
(before the invention of POD) was based on a
trick to mix nroff and perl code. The trick was
built upon these three nroff macros being used in
void context. The pink camel has the details in
the script wrapman near page 319. */
const char * const maybe_macro = SvPVX_const(sv);
if (strnEQ(maybe_macro, "di", 2) ||
strnEQ(maybe_macro, "ds", 2) ||
strnEQ(maybe_macro, "ig", 2))
useless = NULL;
}
}
}
op_null(o); /* don't execute or even remember it */
break;
#ifndef PERL_MAD
case OP_POSTINC:
o->op_type = OP_PREINC; /* pre-increment is faster */
o->op_ppaddr = PL_ppaddr[OP_PREINC];
break;
case OP_POSTDEC:
o->op_type = OP_PREDEC; /* pre-decrement is faster */
o->op_ppaddr = PL_ppaddr[OP_PREDEC];
break;
case OP_I_POSTINC:
o->op_type = OP_I_PREINC; /* pre-increment is faster */
o->op_ppaddr = PL_ppaddr[OP_I_PREINC];
break;
case OP_I_POSTDEC:
o->op_type = OP_I_PREDEC; /* pre-decrement is faster */
o->op_ppaddr = PL_ppaddr[OP_I_PREDEC];
break;
#endif /* MAD */
case OP_OR:
case OP_AND:
case OP_DOR:
case OP_COND_EXPR:
for (kid = cUNOPo->op_first->op_sibling; kid; kid = kid->op_sibling)
scalarvoid(kid);
break;
case OP_NULL:
if (o->op_flags & OPf_STACKED)
break;
/* FALL THROUGH */
case OP_NEXTSTATE:
case OP_DBSTATE:
case OP_ENTERTRY:
case OP_ENTER:
if (!(o->op_flags & OPf_KIDS))
break;
/* FALL THROUGH */
case OP_SCOPE:
case OP_LEAVE:
case OP_LEAVETRY:
case OP_LEAVELOOP:
case OP_LINESEQ:
case OP_LIST:
case OP_LISTLAST:
case OP_LISTFIRST:
for (kid = cLISTOPo->op_first; kid; kid = kid->op_sibling)
scalarvoid(kid);
break;
case OP_SASSIGN:
scalarvoid(cBINOPo->op_last);
break;
case OP_ENTEREVAL:
scalarkids(o);
break;
case OP_REQUIRE:
/* all requires must return a boolean value */
o->op_flags &= ~OPf_WANT;
/* FALL THROUGH */
case OP_SCALAR:
return scalar(o);
case OP_SPLIT:
if ((kid = cLISTOPo->op_first) && kid->op_type == OP_PUSHRE) {
if (!kPMOP->op_pmreplrootu.op_pmreplroot)
deprecate_old("implicit split to @_");
}
break;
}
if (useless && !(o->op_flags & OPf_ASSIGN)
&& ckWARN(WARN_VOID))
Perl_warner_at(aTHX_ o->op_location, packWARN(WARN_VOID), "Useless use of %s in void context", useless);
return o;
}
static AV*
S_mro_get_linear_isa_c3(pTHX_ HV* stash, U32 level)
{
AV* retval;
GV** gvp;
GV* gv;
AV* isa;
const HEK* stashhek;
struct mro_meta* meta;
PERL_ARGS_ASSERT_MRO_GET_LINEAR_ISA_C3;
assert(HvAUX(stash));
stashhek = HvNAME_HEK(stash);
if (!stashhek)
Perl_croak(aTHX_ "Can't linearize anonymous symbol table");
if (level > 100)
Perl_croak(aTHX_ "Recursive inheritance detected in package '%s'",
HEK_KEY(stashhek));
meta = HvMROMETA(stash);
/* return cache if valid */
if((retval = meta->mro_linear_c3)) {
return retval;
}
/* not in cache, make a new one */
gvp = (GV**)hv_fetchs(stash, "ISA", FALSE);
isa = (gvp && (gv = *gvp) && isGV_with_GP(gv)) ? GvAV(gv) : NULL;
if ( isa && ! SvAVOK(isa) ) {
Perl_croak(aTHX_ "@ISA is not an array but %s", Ddesc((SV*)isa));
}
/* For a better idea how the rest of this works, see the much clearer
pure perl version in Algorithm::C3 0.01:
http://search.cpan.org/src/STEVAN/Algorithm-C3-0.01/lib/Algorithm/C3.pm
(later versions go about it differently than this code for speed reasons)
*/
if(isa && AvFILLp(isa) >= 0) {
SV** seqs_ptr;
I32 seqs_items;
HV* const tails = MUTABLE_HV(sv_2mortal(MUTABLE_SV(newHV())));
AV *const seqs = MUTABLE_AV(sv_2mortal(MUTABLE_SV(newAV())));
I32* heads;
/* This builds @seqs, which is an array of arrays.
The members of @seqs are the MROs of
the members of @ISA, followed by @ISA itself.
*/
I32 items = AvFILLp(isa) + 1;
SV** isa_ptr = AvARRAY(isa);
while(items--) {
SV* const isa_item = *isa_ptr++;
if ( ! SvPVOK(isa_item) ) {
Perl_croak(aTHX_ "@ISA element which is not an plain value");
}
{
HV* const isa_item_stash = gv_stashsv(isa_item, 0);
if(!isa_item_stash) {
/* if no stash, make a temporary fake MRO
containing just itself */
AV* const isa_lin = newAV();
av_push(isa_lin, newSVsv(isa_item));
av_push(seqs, (SV*)isa_lin);
}
else {
/* recursion */
AV* const isa_lin = mro_get_linear_isa_c3(isa_item_stash, level + 1);
av_push(seqs, SvREFCNT_inc_NN((SV*)isa_lin));
}
}
}
av_push(seqs, SvREFCNT_inc_NN((SV*)isa));
/* This builds "heads", which as an array of integer array
indices, one per seq, which point at the virtual "head"
of the seq (initially zero) */
Newxz(heads, AvFILLp(seqs)+1, I32);
/* This builds %tails, which has one key for every class
mentioned in the tail of any sequence in @seqs (tail meaning
everything after the first class, the "head"). The value
is how many times this key appears in the tails of @seqs.
*/
seqs_ptr = AvARRAY(seqs);
seqs_items = AvFILLp(seqs) + 1;
while(seqs_items--) {
AV *const seq = MUTABLE_AV(*seqs_ptr++);
I32 seq_items = AvFILLp(seq);
if(seq_items > 0) {
SV** seq_ptr = AvARRAY(seq) + 1;
while(seq_items--) {
SV* const seqitem = *seq_ptr++;
/* LVALUE fetch will create a new undefined SV if necessary
*/
HE* const he = hv_fetch_ent(tails, seqitem, 1, 0);
if(he) {
SV* const val = HeVAL(he);
/* This will increment undef to 1, which is what we
want for a newly created entry. */
sv_inc(val);
}
}
}
}
/* Initialize retval to build the return value in */
retval = newAV();
av_push(retval, newSVhek(stashhek)); /* us first */
/* This loop won't terminate until we either finish building
the MRO, or get an exception. */
while(1) {
SV* cand = NULL;
SV* winner = NULL;
int s;
/* "foreach $seq (@seqs)" */
SV** const avptr = AvARRAY(seqs);
for(s = 0; s <= AvFILLp(seqs); s++) {
SV** svp;
AV * const seq = MUTABLE_AV(avptr[s]);
SV* seqhead;
if(!seq) continue; /* skip empty seqs */
svp = av_fetch(seq, heads[s], 0);
seqhead = *svp; /* seqhead = head of this seq */
if(!winner) {
HE* tail_entry;
SV* val;
/* if we haven't found a winner for this round yet,
and this seqhead is not in tails (or the count
for it in tails has dropped to zero), then this
seqhead is our new winner, and is added to the
final MRO immediately */
cand = seqhead;
if((tail_entry = hv_fetch_ent(tails, cand, 0, 0))
&& (val = HeVAL(tail_entry))
&& (SvIV(val) > 0))
continue;
winner = newSVsv(cand);
av_push(retval, winner);
/* note however that even when we find a winner,
we continue looping over @seqs to do housekeeping */
}
if(!sv_cmp(seqhead, winner)) {
/* Once we have a winner (including the iteration
where we first found him), inc the head ptr
for any seq which had the winner as a head,
NULL out any seq which is now empty,
and adjust tails for consistency */
const int new_head = ++heads[s];
if(new_head > AvFILLp(seq)) {
SvREFCNT_dec(avptr[s]);
avptr[s] = NULL;
}
else {
HE* tail_entry;
SV* val;
/* Because we know this new seqhead used to be
a tail, we can assume it is in tails and has
a positive value, which we need to dec */
svp = av_fetch(seq, new_head, 0);
seqhead = *svp;
tail_entry = hv_fetch_ent(tails, seqhead, 0, 0);
val = HeVAL(tail_entry);
sv_dec(val);
}
}
}
/* if we found no candidates, we are done building the MRO.
!cand means no seqs have any entries left to check */
if(!cand) {
Safefree(heads);
break;
}
/* If we had candidates, but nobody won, then the @ISA
hierarchy is not C3-incompatible */
if(!winner) {
SV *errmsg;
I32 i;
errmsg = newSVpvf(aTHX_ "Inconsistent hierarchy during C3 merge of class '%s':\n\t"
"current merge results [\n", HEK_KEY(stashhek));
for (i = 0; i <= av_len(retval); i++) {
SV **elem = av_fetch(retval, i, 0);
sv_catpvf(aTHX_ errmsg, "\t\t%"SVf",\n", SVfARG(*elem));
}
sv_catpvf(aTHX_ errmsg, "\t]\n\tmerging failed on '%"SVf"'", SVfARG(cand));
/* we have to do some cleanup before we croak */
AvREFCNT_dec(retval);
Safefree(heads);
croak(aTHX_ "%"SVf, SVfARG(errmsg));
}
}
}
else { /* @ISA was undefined or empty */
/* build a retval containing only ourselves */
retval = newAV();
av_push(retval, newSVhek(stashhek));
}
/* we don't want anyone modifying the cache entry but us,
and we do so by replacing it completely */
SvREADONLY_on(retval);
meta->mro_linear_c3 = retval;
return retval;
}
