Localized nonexistant array elements should be deleted when their time comes, so...

[perl/modules/Scope-Upper.git] / Upper.xs

diff --git a/Upper.xs b/Upper.xs
index 7e386a3be3250e63c55f71415eb039e62bd075cd..e9228f1ae9a5a675750bf6e6b4489b969ac5b039 100644 (file)
--- a/Upper.xs
+++ b/Upper.xs
@@ -135,23 +135,81 @@ typedef struct {
  SV *elem;
 } su_ud_localize;
 
-/* Those two functions are courtesy of pp_hot.c:pp_helem */
+#ifndef SvCANEXISTDELETE
+# define SvCANEXISTDELETE(sv) \
+  (!SvRMAGICAL(sv)            \
+   || ((mg = mg_find((SV *) sv, PERL_MAGIC_tied))            \
+       && (stash = SvSTASH(SvRV(SvTIED_obj((SV *) sv, mg)))) \
+       && gv_fetchmethod_autoload(stash, "EXISTS", TRUE)     \
+       && gv_fetchmethod_autoload(stash, "DELETE", TRUE)     \
+      )                       \
+   )
+#endif
+
+STATIC I32 su_av_preeminent(pTHX_ AV *av, I32 key) {
+#define su_av_preeminent(A, K) su_av_preeminent(aTHX_ (A), (K))
+ MAGIC *mg;
+ HV *stash;
+
+ if (!av)
+  return 0;
+ if (SvCANEXISTDELETE(av))
+  return av_exists(av, key);
+
+ return 1;
+}
+
+#ifndef SAVEADELETE
+
+typedef struct {
+ AV *av;
+ I32 key;
+} su_ud_adelete;
+
+STATIC void su_adelete(pTHX_ void *ud_) {
+ su_ud_adelete *ud = ud_;
+
+ av_delete(ud->av, ud->key, G_DISCARD);
+ SvREFCNT_dec(ud->av);
+
+ Safefree(ud);
+}
+
+STATIC void su_save_adelete(pTHX_ AV *av, I32 key) {
+#define su_save_adelete(A, K) su_save_adelete(aTHX_ (A), (K))
+ su_ud_adelete *ud;
+
+ Newx(ud, 1, su_ud_adelete);
+ ud->av  = av;
+ ud->key = key;
+ SvREFCNT_inc(av);
+
+ SAVEDESTRUCTOR_X(su_adelete, ud);
+}
+
+#define SAVEADELETE(A, K) su_save_adelete((A), (K))
+
+#endif /* SAVEADELETE */
+
+STATIC void su_save_aelem(pTHX_ AV *av, I32 key, SV **svp, I32 preeminent) {
+#define su_save_aelem(A, K, S, P) su_save_aelem(aTHX_ (A), (K), (S), (P))
+ if (preeminent)
+  save_aelem(av, key, svp);
+ else
+  SAVEADELETE(av, key);
+}
 
 STATIC I32 su_hv_preeminent(pTHX_ HV *hv, SV *keysv) {
 #define su_hv_preeminent(H, K) su_hv_preeminent(aTHX_ (H), (K))
  MAGIC *mg;
  HV *stash;
- return (!SvRMAGICAL(hv)
-         || mg_find((SV *) hv, PERL_MAGIC_env)
-         || ((mg = mg_find((SV *) hv, PERL_MAGIC_tied))
-                   /* Try to preserve the existenceness of a tied hash
-                    * element by using EXISTS and DELETE if possible.
-                    * Fallback to FETCH and STORE otherwise */
-             && (stash = SvSTASH(SvRV(SvTIED_obj((SV *) hv, mg))))
-             && gv_fetchmethod_autoload(stash, "EXISTS", TRUE)
-             && gv_fetchmethod_autoload(stash, "DELETE", TRUE)
-            )
-        ) ? hv_exists_ent(hv, keysv, 0) : 1;
+
+ if (!hv)
+  return 0;
+ if (SvCANEXISTDELETE(hv) || mg_find((SV *) hv, PERL_MAGIC_env))
+  return hv_exists_ent(hv, keysv, 0);
+
+ return 1;
 }
 
 STATIC void su_save_helem(pTHX_ HV *hv, SV *keysv, SV **svp, I32 preeminent) {
@@ -229,9 +287,10 @@ STATIC void su_localize(pTHX_ void *ud_) {
    if (elem) {
     I32 idx  = SvIV(elem);
     AV *av   = GvAV(gv);
+    I32 preeminent = su_av_preeminent(av, idx);
     SV **svp = av_fetch(av, idx, 1);
     if (!*svp || *svp == &PL_sv_undef) croak(PL_no_aelem, idx);
-    save_aelem(av, idx, svp);
+    su_save_aelem(av, idx, svp, preeminent);
     gv = (GV *) *svp;
     goto maybe_deref;
    } else
@@ -240,7 +299,7 @@ STATIC void su_localize(pTHX_ void *ud_) {
   case SVt_PVHV:
    if (elem) {
     HV *hv   = GvHV(gv);
-    I32 preeminent = hv ? su_hv_preeminent(hv, elem) : 0;
+    I32 preeminent = su_hv_preeminent(hv, elem);
     HE *he   = hv_fetch_ent(hv, elem, 1, 0);
     SV **svp = he ? &HeVAL(he) : NULL;
     if (!svp || *svp == &PL_sv_undef) croak("Modification of non-creatable hash value attempted, subscript \"%s\"", SvPV_nolen_const(*svp));