X-Git-Url: http://git.vpit.fr/?a=blobdiff_plain;f=Upper.xs;h=92f9e65b4f0e09573b28c7dd9e8ab6bf54b44607;hb=a06eb7aacdd80daabe3b1565c15b37096ea2b57c;hp=07b97414f531f9310757d97b281bfab3886d7f0c;hpb=84566b6479d4169e7c76ea33ca3885be70735303;p=perl%2Fmodules%2FScope-Upper.git

diff --git a/Upper.xs b/Upper.xs
index 07b9741..92f9e65 100644
--- a/Upper.xs
+++ b/Upper.xs
@@ -6,12 +6,18 @@
 #include "perl.h" 
 #include "XSUB.h"
 
+#define __PACKAGE__ "Scope::Upper"
+
 #ifndef SU_DEBUG
 # define SU_DEBUG 0
 #endif
 
 /* --- Compatibility ------------------------------------------------------- */
 
+#ifndef PERL_UNUSED_VAR
+# define PERL_UNUSED_VAR(V)
+#endif
+
 #ifndef STMT_START
 # define STMT_START do
 #endif
@@ -38,6 +44,10 @@
 # define SvPV_nolen_const(S) SvPV_nolen(S)
 #endif
 
+#ifndef SvREFCNT_inc_simple_void
+# define SvREFCNT_inc_simple_void(sv) SvREFCNT_inc(sv)
+#endif
+
 #ifndef HvNAME_get
 # define HvNAME_get(H) HvNAME(H)
 #endif
@@ -54,10 +64,75 @@
 # define PERL_MAGIC_env 'E'
 #endif
 
+#ifndef NEGATIVE_INDICES_VAR
+# define NEGATIVE_INDICES_VAR "NEGATIVE_INDICES"
+#endif
+
 #define SU_HAS_PERL(R, V, S) (PERL_REVISION > (R) || (PERL_REVISION == (R) && (PERL_VERSION > (V) || (PERL_VERSION == (V) && (PERL_SUBVERSION >= (S))))))
 
+/* --- Threads and multiplicity -------------------------------------------- */
+
+#ifndef NOOP
+# define NOOP
+#endif
+
+#ifndef dNOOP
+# define dNOOP
+#endif
+
+#ifndef SU_MULTIPLICITY
+# if defined(MULTIPLICITY) || defined(PERL_IMPLICIT_CONTEXT)
+#  define SU_MULTIPLICITY 1
+# else
+#  define SU_MULTIPLICITY 0
+# endif
+#endif
+#if SU_MULTIPLICITY && !defined(tTHX)
+# define tTHX PerlInterpreter*
+#endif
+
+#if SU_MULTIPLICITY && defined(USE_ITHREADS) && defined(dMY_CXT) && defined(MY_CXT) && defined(START_MY_CXT) && defined(MY_CXT_INIT) && (defined(MY_CXT_CLONE) || defined(dMY_CXT_SV))
+# define SU_THREADSAFE 1
+# ifndef MY_CXT_CLONE
+#  define MY_CXT_CLONE \
+    dMY_CXT_SV;                                                      \
+    my_cxt_t *my_cxtp = (my_cxt_t*)SvPVX(newSV(sizeof(my_cxt_t)-1)); \
+    Copy(INT2PTR(my_cxt_t*, SvUV(my_cxt_sv)), my_cxtp, 1, my_cxt_t); \
+    sv_setuv(my_cxt_sv, PTR2UV(my_cxtp))
+# endif
+#else
+# define SU_THREADSAFE 0
+# undef  dMY_CXT
+# define dMY_CXT      dNOOP
+# undef  MY_CXT
+# define MY_CXT       su_globaldata
+# undef  START_MY_CXT
+# define START_MY_CXT STATIC my_cxt_t MY_CXT;
+# undef  MY_CXT_INIT
+# define MY_CXT_INIT  NOOP
+# undef  MY_CXT_CLONE
+# define MY_CXT_CLONE NOOP
+#endif
+
+/* --- Global data --------------------------------------------------------- */
+
+#define MY_CXT_KEY __PACKAGE__ "::_guts" XS_VERSION
+
+typedef struct {
+ int stack_placeholder;
+ I32 cxix;
+ I32 items;
+ SV  **savesp;
+ OP  fakeop;
+} my_cxt_t;
+
+START_MY_CXT
+
 /* --- Stack manipulations ------------------------------------------------- */
 
+#define SU_SAVE_DESTRUCTOR_SIZE 3
+#define SU_SAVE_INT_SIZE        3
+
 #ifndef SvCANEXISTDELETE
 # define SvCANEXISTDELETE(sv) \
   (!SvRMAGICAL(sv)            \
@@ -71,30 +146,58 @@
 
 /* ... Saving array elements ............................................... */
 
+STATIC I32 su_av_key2idx(pTHX_ AV *av, I32 key) {
+#define su_av_key2idx(A, K) su_av_key2idx(aTHX_ (A), (K))
+ I32 idx;
+
+ if (key >= 0)
+  return key;
+
+/* Added by MJD in perl-5.8.1 with 6f12eb6d2a1dfaf441504d869b27d2e40ef4966a */
+#if SU_HAS_PERL(5, 8, 1)
+ if (SvRMAGICAL(av)) {
+  const MAGIC * const tied_magic = mg_find((SV *) av, PERL_MAGIC_tied);
+  if (tied_magic) {
+   SV * const * const negative_indices_glob =
+                    hv_fetch(SvSTASH(SvRV(SvTIED_obj((SV *) (av), tied_magic))),
+                             NEGATIVE_INDICES_VAR, 16, 0);
+   if (negative_indices_glob && SvTRUE(GvSV(*negative_indices_glob)))
+    return key;
+  }
+ }
+#endif
+
+ idx = key + av_len(av) + 1;
+ if (idx < 0)
+  return key;
+
+ return idx;
+}
+
 #ifndef SAVEADELETE
 
 typedef struct {
  AV *av;
- I32 key;
+ I32 idx;
 } su_ud_adelete;
 
 STATIC void su_adelete(pTHX_ void *ud_) {
- su_ud_adelete *ud = ud_;
+ su_ud_adelete *ud = (su_ud_adelete *) ud_;
 
- av_delete(ud->av, ud->key, G_DISCARD);
+ av_delete(ud->av, ud->idx, G_DISCARD);
  SvREFCNT_dec(ud->av);
 
  Safefree(ud);
 }
 
-STATIC void su_save_adelete(pTHX_ AV *av, I32 key) {
+STATIC void su_save_adelete(pTHX_ AV *av, I32 idx) {
 #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);
+ ud->idx = idx;
+ SvREFCNT_inc_simple_void(av);
 
  SAVEDESTRUCTOR_X(su_adelete, ud);
 }
@@ -105,17 +208,19 @@ STATIC void su_save_adelete(pTHX_ AV *av, I32 key) {
 
 STATIC void su_save_aelem(pTHX_ AV *av, SV *key, SV *val) {
 #define su_save_aelem(A, K, V) su_save_aelem(aTHX_ (A), (K), (V))
- I32 idx = SvIV(key);
+ I32 idx;
  I32 preeminent = 1;
  SV **svp;
  HV *stash;
  MAGIC *mg;
 
+ idx = su_av_key2idx(av, SvIV(key));
+
  if (SvCANEXISTDELETE(av))
   preeminent = av_exists(av, idx);
 
  svp = av_fetch(av, idx, 1);
- if (!*svp || *svp == &PL_sv_undef) croak(PL_no_aelem, idx);
+ if (!svp || *svp == &PL_sv_undef) croak(PL_no_aelem, idx);
 
  if (preeminent)
   save_aelem(av, idx, svp);
@@ -163,7 +268,7 @@ STATIC void su_save_helem(pTHX_ HV *hv, SV *keysv, SV *val) {
  if (val) { /* local $x{$keysv} = $val; */
   SvSetMagicSV(*svp, val);
  } else {   /* local $x{$keysv}; delete $x{$keysv}; */
-  hv_delete_ent(hv, keysv, G_DISCARD, HeHASH(he));
+  (void)hv_delete_ent(hv, keysv, G_DISCARD, HeHASH(he));
  }
 }
 
@@ -171,11 +276,13 @@ STATIC void su_save_helem(pTHX_ HV *hv, SV *keysv, SV *val) {
 
 typedef struct {
  I32 depth;
+ I32 pad;
  I32 *origin;
  void (*handler)(pTHX_ void *);
 } su_ud_common;
 
 #define SU_UD_DEPTH(U)   (((su_ud_common *) (U))->depth)
+#define SU_UD_PAD(U)     (((su_ud_common *) (U))->pad)
 #define SU_UD_ORIGIN(U)  (((su_ud_common *) (U))->origin)
 #define SU_UD_HANDLER(U) (((su_ud_common *) (U))->handler)
 
@@ -193,39 +300,42 @@ typedef struct {
 
 STATIC void su_call(pTHX_ void *ud_) {
  su_ud_reap *ud = (su_ud_reap *) ud_;
-#if SU_HAS_PERL(5, 10, 0)
- I32 dieing = PL_op->op_type == OP_DIE;
+#if SU_HAS_PERL(5, 9, 5)
+ PERL_CONTEXT saved_cx;
+ I32 cxix;
 #endif
 
  dSP;
 
- SU_D(PerlIO_printf(Perl_debug_log, "%p: @@@ call at %d (save is %d)\n",
-                                     ud, PL_scopestack_ix, PL_savestack_ix));
+ SU_D({
+  PerlIO_printf(Perl_debug_log,
+                "%p: @@@ call\n%p: depth=%2d scope_ix=%2d save_ix=%2d\n",
+                 ud, ud, SU_UD_DEPTH(ud), PL_scopestack_ix, PL_savestack_ix);
+ });
+
  ENTER;
  SAVETMPS;
 
  PUSHMARK(SP);
  PUTBACK;
 
- /* If cxstack_ix isn't incremented there, the eval context will be overwritten
-  * when the new sub scope will be created in call_sv. */
+ /* If the recently popped context isn't saved there, it will be overwritten by
+  * the sub scope from call_sv, although it's still needed in our caller. */
 
-#if SU_HAS_PERL(5, 10, 0)
- if (dieing)
-  if (cxstack_ix < cxstack_max)
-   ++cxstack_ix;
-  else
-   cxstack_ix = Perl_cxinc(aTHX);
+#if SU_HAS_PERL(5, 9, 5)
+ if (cxstack_ix < cxstack_max)
+  cxix = cxstack_ix + 1;
+ else
+  cxix = Perl_cxinc(aTHX);
+ saved_cx = cxstack[cxix];
 #endif
 
  call_sv(ud->cb, G_VOID);
 
-#if SU_HAS_PERL(5, 10, 0)
- if (dieing && cxstack_ix > 0)
-  --cxstack_ix;
+#if SU_HAS_PERL(5, 9, 5)
+ cxstack[cxix] = saved_cx;
 #endif
 
- SPAGAIN;
  PUTBACK;
 
  FREETMPS;
@@ -237,43 +347,42 @@ STATIC void su_call(pTHX_ void *ud_) {
 
 STATIC void su_reap(pTHX_ void *ud) {
 #define su_reap(U) su_reap(aTHX_ (U))
- SU_D(PerlIO_printf(Perl_debug_log, "%p: === reap at %d (save is %d)\n",
-                                     ud, PL_scopestack_ix, PL_savestack_ix));
+ SU_D({
+  PerlIO_printf(Perl_debug_log,
+                "%p: === reap\n%p: depth=%2d scope_ix=%2d save_ix=%2d\n",
+                 ud, ud, SU_UD_DEPTH(ud), PL_scopestack_ix, PL_savestack_ix);
+ });
+
  SAVEDESTRUCTOR_X(su_call, ud);
- SU_D(PerlIO_printf(Perl_debug_log, "%p: savestack is now at %d, base at %d\n",
-                                     ud, PL_savestack_ix,
-                                         PL_scopestack[PL_scopestack_ix]));
 }
 
 /* ... Localize & localize array/hash element .............................. */
 
 typedef struct {
  su_ud_common ci;
- SV *sv;
- SV *val;
- SV *elem;
+ SV    *sv;
+ SV    *val;
+ SV    *elem;
+ svtype type;
 } su_ud_localize;
 
-STATIC void su_localize(pTHX_ void *ud_) {
-#define su_localize(U) su_localize(aTHX_ (U))
- su_ud_localize *ud = (su_ud_localize *) ud_;
- SV *sv   = ud->sv;
- SV *val  = ud->val;
- SV *elem = ud->elem;
- GV *gv;
+STATIC void su_ud_localize_init(pTHX_ su_ud_localize *ud, SV *sv, SV *val, SV *elem) {
+#define su_ud_localize_init(UD, S, V, E) su_ud_localize_init(aTHX_ (UD), (S), (V), (E))
  UV deref = 0;
  svtype t = SVt_NULL;
 
+ SvREFCNT_inc_simple_void(sv);
+
  if (SvTYPE(sv) >= SVt_PVGV) {
-  gv = (GV *) sv;
-  if (!val) {               /* local *x; */
+  if (!val || !SvROK(val)) { /* local *x; or local *x = $val; */
    t = SVt_PVGV;
-  } else if (!SvROK(val)) { /* local *x = $val; */
-   goto assign;
-  } else {                  /* local *x = \$val; */
+  } else {                   /* local *x = \$val; */
    t = SvTYPE(SvRV(val));
    deref = 1;
   }
+ } else if (SvROK(sv)) {
+  croak("Invalid %s reference as the localization target",
+                 sv_reftype(SvRV(sv), 0));
  } else {
   STRLEN len, l;
   const char *p = SvPV_const(sv, len), *s;
@@ -300,14 +409,55 @@ STATIC void su_localize(pTHX_ void *ud_) {
     t = SvTYPE(val);
    }
   }
-  gv = gv_fetchpvn_flags(s, l, GV_ADDMULTI, SVt_PVGV);
+  SvREFCNT_dec(sv);
+  sv = newSVpvn(s, l);
+ }
+
+ switch (t) {
+  case SVt_PVAV:
+  case SVt_PVHV:
+  case SVt_PVCV:
+  case SVt_PVGV:
+   deref = 0;
+  default:
+   break;
+ }
+ /* When deref is set, val isn't NULL */
+
+ ud->sv   = sv;
+ ud->val  = val ? newSVsv(deref ? SvRV(val) : val) : NULL;
+ ud->elem = SvREFCNT_inc(elem);
+ ud->type = t;
+}
+
+STATIC void su_localize(pTHX_ void *ud_) {
+#define su_localize(U) su_localize(aTHX_ (U))
+ su_ud_localize *ud = (su_ud_localize *) ud_;
+ SV *sv   = ud->sv;
+ SV *val  = ud->val;
+ SV *elem = ud->elem;
+ svtype t = ud->type;
+ GV *gv;
+
+ if (SvTYPE(sv) >= SVt_PVGV) {
+  gv = (GV *) sv;
+ } else {
+#ifdef gv_fetchsv
+  gv = gv_fetchsv(sv, GV_ADDMULTI, t);
+#else
+  STRLEN len;
+  const char *name = SvPV_const(sv, len);
+  gv = gv_fetchpvn_flags(name, len, GV_ADDMULTI, t);
+#endif
  }
 
  SU_D({
-  SV *z = newSV_type(t);
-  PerlIO_printf(Perl_debug_log, "%p: === localize a %s at %d (save is %d)\n",
-                                 ud, sv_reftype(z, 0),
-                                     PL_scopestack_ix, PL_savestack_ix);
+  SV *z = newSV(0);
+  SvUPGRADE(z, t);
+  PerlIO_printf(Perl_debug_log, "%p: === localize a %s\n",ud, sv_reftype(z, 0));
+  PerlIO_printf(Perl_debug_log,
+                "%p: depth=%2d scope_ix=%2d save_ix=%2d\n",
+                 ud, SU_UD_DEPTH(ud), PL_scopestack_ix, PL_savestack_ix);
   SvREFCNT_dec(z);
  });
 
@@ -315,16 +465,14 @@ STATIC void su_localize(pTHX_ void *ud_) {
  switch (t) {
   case SVt_PVAV:
    if (elem) {
-    AV *av = GvAV(gv);
-    su_save_aelem(av, elem, val);
+    su_save_aelem(GvAV(gv), elem, val);
     goto done;
    } else
     save_ary(gv);
    break;
   case SVt_PVHV:
    if (elem) {
-    HV *hv = GvHV(gv);
-    su_save_helem(hv, elem, val);
+    su_save_helem(GvHV(gv), elem, val);
     goto done;
    } else
     save_hash(gv);
@@ -338,17 +486,9 @@ STATIC void su_localize(pTHX_ void *ud_) {
    break;
   default:
    gv = (GV *) save_scalar(gv);
-maybe_deref:
-   if (deref) /* val != NULL */
-    val = SvRV(val);
    break;
  }
 
- SU_D(PerlIO_printf(Perl_debug_log, "%p: savestack is now at %d, base at %d\n",
-                                     ud, PL_savestack_ix,
-                                         PL_scopestack[PL_scopestack_ix]));
-
-assign:
  if (val)
   SvSetMagicSV((SV *) gv, val);
 
@@ -374,55 +514,92 @@ STATIC void su_pop(pTHX_ void *ud) {
  I32 depth, base, mark, *origin;
  depth = SU_UD_DEPTH(ud);
 
- SU_D(PerlIO_printf(Perl_debug_log, "%p: --- pop %s at %d from %d to %d [%d]\n",
-                                     ud, SU_CXNAME,
-                                         PL_scopestack_ix, PL_savestack_ix,
-                                         PL_scopestack[PL_scopestack_ix],
-                                         depth));
+ SU_D(
+  PerlIO_printf(Perl_debug_log,
+   "%p: --- pop a %s\n"
+   "%p: leave scope     at depth=%2d scope_ix=%2d cur_top=%2d cur_base=%2d\n",
+    ud, SU_CXNAME,
+    ud, depth, PL_scopestack_ix,PL_savestack_ix,PL_scopestack[PL_scopestack_ix])
+ );
 
  origin = SU_UD_ORIGIN(ud);
  mark   = origin[depth];
  base   = origin[depth - 1];
 
- SU_D(PerlIO_printf(Perl_debug_log, "%p: clean from %d down to %d\n",
-                                     ud, mark, base));
+ SU_D(PerlIO_printf(Perl_debug_log,
+                    "%p: original scope was %*c top=%2d     base=%2d\n",
+                     ud,                24, ' ',    mark,        base));
 
  if (base < mark) {
+  SU_D(PerlIO_printf(Perl_debug_log, "%p: clear leftovers\n", ud));
   PL_savestack_ix = mark;
   leave_scope(base);
  }
  PL_savestack_ix = base;
- if (--depth > 0) {
-  SU_UD_DEPTH(ud) = depth;
-  SU_D(PerlIO_printf(Perl_debug_log, "%p: save new destructor at %d [%d]\n",
-                                      ud, PL_savestack_ix, depth));
+
+ SU_UD_DEPTH(ud) = --depth;
+
+ if (depth > 0) {
+  I32 pad;
+
+  if ((pad = SU_UD_PAD(ud))) {
+   dMY_CXT;
+   do {
+    SU_D(PerlIO_printf(Perl_debug_log,
+          "%p: push a pad slot at depth=%2d scope_ix=%2d save_ix=%2d\n",
+           ud,                       depth, PL_scopestack_ix, PL_savestack_ix));
+    save_int(&MY_CXT.stack_placeholder);
+   } while (--pad);
+  }
+
+  SU_D(PerlIO_printf(Perl_debug_log,
+          "%p: push destructor at depth=%2d scope_ix=%2d save_ix=%2d\n",
+           ud,                       depth, PL_scopestack_ix, PL_savestack_ix));
   SAVEDESTRUCTOR_X(su_pop, ud);
-  SU_D(PerlIO_printf(Perl_debug_log, "%p: pop end at at %d [%d]\n",
-                                      ud, PL_savestack_ix, depth));
  } else {
   SU_UD_HANDLER(ud)(aTHX_ ud);
  }
+
+ SU_D(PerlIO_printf(Perl_debug_log,
+                    "%p: --- end pop: cur_top=%2d == cur_base=%2d\n",
+                     ud, PL_savestack_ix, PL_scopestack[PL_scopestack_ix]));
 }
 
 /* --- Initialize the stack and the action userdata ------------------------ */
 
-STATIC I32 su_init(pTHX_ I32 level, void *ud, I32 size) {
+STATIC I32 su_init(pTHX_ I32 cxix, void *ud, I32 size) {
 #define su_init(L, U, S) su_init(aTHX_ (L), (U), (S))
- I32 i, depth = 0, *origin;
- I32 cur, last, step;
+ I32 i, depth = 1, pad, offset, *origin;
 
- LEAVE;
+ SU_D(PerlIO_printf(Perl_debug_log, "%p: ### init for cx %d\n", ud, cxix));
 
- if (level <= 0) {
-  SU_UD_HANDLER(ud)(aTHX_ ud);
-  goto done;
+ if (size <= SU_SAVE_DESTRUCTOR_SIZE)
+  pad = 0;
+ else {
+  I32 extra = size - SU_SAVE_DESTRUCTOR_SIZE;
+  pad = extra / SU_SAVE_INT_SIZE + ((extra % SU_SAVE_INT_SIZE) ? 1 : 0);
  }
+ offset = SU_SAVE_DESTRUCTOR_SIZE + SU_SAVE_INT_SIZE * pad;
 
- SU_D(PerlIO_printf(Perl_debug_log, "%p: ### init for level %d\n", ud, level));
+ SU_D(PerlIO_printf(Perl_debug_log, "%p: size=%d pad=%d offset=%d\n",
+                                     ud,    size,   pad,   offset));
 
- for (i = 0; i < level; ++i) {
-  PERL_CONTEXT *cx = &cxstack[cxstack_ix - i];
+ for (i = cxstack_ix; i > cxix; --i) {
+  PERL_CONTEXT *cx = cxstack + i;
   switch (CxTYPE(cx)) {
+#if SU_HAS_PERL(5, 10, 0)
+   case CXt_BLOCK:
+    SU_D(PerlIO_printf(Perl_debug_log, "%p: cx %d is block\n", ud, i));
+    /* Given and when blocks are actually followed by a simple block, so skip
+     * it if needed. */
+    if (cxix > 0) { /* Implies i > 0 */
+     PERL_CONTEXT *next = cx - 1;
+     if (CxTYPE(next) == CXt_GIVEN || CxTYPE(next) == CXt_WHEN)
+      --cxix;
+    }
+    depth++;
+    break;
+#endif
 #if SU_HAS_PERL(5, 11, 0)
    case CXt_LOOP_FOR:
    case CXt_LOOP_PLAIN:
@@ -435,12 +612,12 @@ STATIC I32 su_init(pTHX_ I32 level, void *ud, I32 size) {
     depth += 2;
     break;
    default:
-    SU_D(PerlIO_printf(Perl_debug_log, "%p: cx %d is normal\n", ud, i));
+    SU_D(PerlIO_printf(Perl_debug_log, "%p: cx %d is other\n", ud, i));
     depth++;
     break;
   }
  }
- SU_D(PerlIO_printf(Perl_debug_log, "%p: depth is %d\n", ud, depth));
+ SU_D(PerlIO_printf(Perl_debug_log, "%p: going down to depth %d\n", ud, depth));
 
  Newx(origin, depth + 1, I32);
  origin[0] = PL_scopestack[PL_scopestack_ix - depth];
@@ -448,122 +625,429 @@ STATIC I32 su_init(pTHX_ I32 level, void *ud, I32 size) {
  for (i = depth - 1; i >= 1; --i) {
   I32 j = PL_scopestack_ix - i;
   origin[depth - i] = PL_scopestack[j];
-  PL_scopestack[j] += 3;
+  PL_scopestack[j] += offset;
  }
  origin[depth] = PL_savestack_ix;
 
+ SU_UD_ORIGIN(ud) = origin;
+ SU_UD_DEPTH(ud)  = depth;
+ SU_UD_PAD(ud)    = pad;
+
+ /* Make sure the first destructor fires by pushing enough fake slots on the
+  * stack. */
+ if (PL_savestack_ix + SU_SAVE_DESTRUCTOR_SIZE
+                                       <= PL_scopestack[PL_scopestack_ix - 1]) {
+  dMY_CXT;
+  do {
+   SU_D(PerlIO_printf(Perl_debug_log,
+                  "%p: push a fake slot      at scope_ix=%2d  save_ix=%2d\n",
+                   ud,                      PL_scopestack_ix, PL_savestack_ix));
+   save_int(&MY_CXT.stack_placeholder);
+  } while (PL_savestack_ix + SU_SAVE_DESTRUCTOR_SIZE
+                                        <= PL_scopestack[PL_scopestack_ix - 1]);
+ }
+ SU_D(PerlIO_printf(Perl_debug_log,
+                  "%p: push first destructor at scope_ix=%2d  save_ix=%2d\n",
+                   ud,                      PL_scopestack_ix, PL_savestack_ix));
+ SAVEDESTRUCTOR_X(su_pop, ud);
+
  SU_D({
-  PerlIO_printf(Perl_debug_log, "%p: d=%d s=%d x=%d c=%d o=%d\n", ud,
-                depth, 0, PL_scopestack_ix - 1, PL_savestack_ix, origin[depth]);
-  for (i = depth - 1; i >= 0; --i) {
-   I32 x = PL_scopestack_ix  - depth + i;
-   PerlIO_printf(Perl_debug_log, "%p: d=%d s=%d x=%d c=%d o=%d\n", ud,
-                                  i, depth - i, x, PL_scopestack[x], origin[i]);
+  for (i = 0; i <= depth; ++i) {
+   I32 j = PL_scopestack_ix  - i;
+   PerlIO_printf(Perl_debug_log,
+                 "%p: depth=%2d scope_ix=%2d saved_floor=%2d new_floor=%2d\n",
+                  ud,        i, j, origin[depth - i],
+                                   i == 0 ? PL_savestack_ix : PL_scopestack[j]);
   }
  });
 
- SU_UD_ORIGIN(ud) = origin;
- SU_UD_DEPTH(ud)  = depth;
+ return depth;
+}
 
- SU_D(PerlIO_printf(Perl_debug_log, "%p: set original destructor at %d [%d]\n",
-                                     ud, PL_savestack_ix, depth));
+/* --- Unwind stack -------------------------------------------------------- */
 
- SAVEDESTRUCTOR_X(su_pop, ud);
+STATIC void su_unwind(pTHX_ void *ud_) {
+ dMY_CXT;
+ I32 cxix    = MY_CXT.cxix;
+ I32 items   = MY_CXT.items - 1;
+ SV **savesp = MY_CXT.savesp;
+ I32 mark;
 
-done:
- ENTER;
+ PERL_UNUSED_VAR(ud_);
 
- return depth;
-}
+ if (savesp)
+  PL_stack_sp = savesp;
+
+ if (cxstack_ix > cxix)
+  dounwind(cxix);
+
+ /* Hide the level */
+ if (items >= 0)
+  PL_stack_sp--;
+
+ mark = PL_markstack[cxstack[cxix].blk_oldmarksp];
+ *PL_markstack_ptr = PL_stack_sp - PL_stack_base - items;
+
+ SU_D({
+  I32 gimme = GIMME_V;
+  PerlIO_printf(Perl_debug_log,
+                "%p: cx=%d gimme=%s items=%d sp=%d oldmark=%d mark=%d\n",
+                &MY_CXT, cxix,
+                gimme == G_VOID ? "void" : gimme == G_ARRAY ? "list" : "scalar",
+                items, PL_stack_sp - PL_stack_base, *PL_markstack_ptr, mark);
+ });
+
+ PL_op = PL_ppaddr[OP_RETURN](aTHX);
+ *PL_markstack_ptr = mark;
 
-#define SU_GET_LEVEL(A)  \
- if (items > A) {        \
-  SV *lsv = ST(A);       \
-  if (SvOK(lsv))         \
-   level = SvUV(lsv);    \
-  if (level < 0)         \
-   XSRETURN(0);          \
- }                       \
- if (level > cxstack_ix) \
-  level = cxstack_ix;
+ MY_CXT.fakeop.op_next = PL_op;
+ PL_op = &(MY_CXT.fakeop);
+}
 
 /* --- XS ------------------------------------------------------------------ */
 
+#if SU_HAS_PERL(5, 8, 9)
+# define SU_SKIP_DB_MAX 2
+#else
+# define SU_SKIP_DB_MAX 3
+#endif
+
+/* Skip context sequences of 1 to SU_SKIP_DB_MAX (included) block contexts
+ * followed by a DB sub */
+
+#define SU_SKIP_DB(C) \
+ STMT_START {         \
+  I32 skipped = 0;    \
+  PERL_CONTEXT *base = cxstack;      \
+  PERL_CONTEXT *cx   = base + (C);   \
+  while (cx >= base && (C) > skipped && CxTYPE(cx) == CXt_BLOCK) \
+   --cx, ++skipped;                  \
+  if (cx >= base && (C) > skipped) { \
+   switch (CxTYPE(cx)) {  \
+    case CXt_SUB:         \
+     if (skipped <= SU_SKIP_DB_MAX && cx->blk_sub.cv == GvCV(PL_DBsub)) \
+      (C) -= skipped + 1; \
+      break;              \
+    default:              \
+     break;               \
+   }                      \
+  }                       \
+ } STMT_END
+
+#define SU_GET_CONTEXT(A, B)   \
+ STMT_START {                  \
+  if (items > A) {             \
+   SV *csv = ST(B);            \
+   if (!SvOK(csv))             \
+    goto default_cx;           \
+   cxix = SvIV(csv);           \
+   if (cxix < 0)               \
+    cxix = 0;                  \
+   else if (cxix > cxstack_ix) \
+    cxix = cxstack_ix;         \
+  } else {                     \
+default_cx:                    \
+   cxix = cxstack_ix;          \
+   if (PL_DBsub)               \
+    SU_SKIP_DB(cxix);          \
+  }                            \
+ } STMT_END
+
+#define SU_GET_LEVEL(A, B) \
+ STMT_START {              \
+  level = 0;               \
+  if (items > 0) {         \
+   SV *lsv = ST(B);        \
+   if (SvOK(lsv)) {        \
+    level = SvIV(lsv);     \
+    if (level < 0)         \
+     level = 0;            \
+   }                       \
+  }                        \
+ } STMT_END
+
+XS(XS_Scope__Upper_unwind); /* prototype to pass -Wmissing-prototypes */
+
+XS(XS_Scope__Upper_unwind) {
+#ifdef dVAR
+ dVAR; dXSARGS;
+#else
+ dXSARGS;
+#endif
+ dMY_CXT;
+ I32 cxix;
+
+ PERL_UNUSED_VAR(cv); /* -W */
+ PERL_UNUSED_VAR(ax); /* -Wall */
+
+ SU_GET_CONTEXT(0, items - 1);
+ do {
+  PERL_CONTEXT *cx = cxstack + cxix;
+  switch (CxTYPE(cx)) {
+   case CXt_SUB:
+    if (PL_DBsub && cx->blk_sub.cv == GvCV(PL_DBsub))
+     continue;
+   case CXt_EVAL:
+   case CXt_FORMAT:
+    MY_CXT.cxix  = cxix;
+    MY_CXT.items = items;
+    /* pp_entersub will want to sanitize the stack after returning from there
+     * Screw that, we're insane */
+    if (GIMME_V == G_SCALAR) {
+     MY_CXT.savesp = PL_stack_sp;
+     /* dXSARGS calls POPMARK, so we need to match PL_markstack_ptr[1] */
+     PL_stack_sp = PL_stack_base + PL_markstack_ptr[1] + 1;
+    } else {
+     MY_CXT.savesp = NULL;
+    }
+    SAVEDESTRUCTOR_X(su_unwind, NULL);
+    return;
+   default:
+    break;
+  }
+ } while (--cxix >= 0);
+ croak("Can't return outside a subroutine");
+}
+
 MODULE = Scope::Upper            PACKAGE = Scope::Upper
 
 PROTOTYPES: ENABLE
 
+BOOT:
+{
+ HV *stash;
+
+ MY_CXT_INIT;
+ MY_CXT.stack_placeholder = 0;
+
+ stash = gv_stashpv(__PACKAGE__, 1);
+ newCONSTSUB(stash, "TOP",           newSViv(0));
+ newCONSTSUB(stash, "SU_THREADSAFE", newSVuv(SU_THREADSAFE));
+
+ newXSproto("Scope::Upper::unwind", XS_Scope__Upper_unwind, file, NULL);
+}
+
+#if SU_THREADSAFE
+
+void
+CLONE(...)
+PROTOTYPE: DISABLE
+CODE:
+ PERL_UNUSED_VAR(items);
+ {
+  MY_CXT_CLONE;
+ }
+
+#endif /* SU_THREADSAFE */
+
 SV *
-TOPLEVEL()
+HERE()
 PROTOTYPE:
+PREINIT:
+ I32 cxix = cxstack_ix;
+CODE:
+ if (PL_DBsub)
+  SU_SKIP_DB(cxix);
+ RETVAL = newSViv(cxix);
+OUTPUT:
+ RETVAL
+
+SV *
+UP(...)
+PROTOTYPE: ;$
+PREINIT:
+ I32 cxix;
 CODE:
- RETVAL = newSViv(cxstack_ix);
+ SU_GET_CONTEXT(0, 0);
+ if (--cxix < 0)
+  cxix = 0;
+ if (PL_DBsub)
+  SU_SKIP_DB(cxix);
+ RETVAL = newSViv(cxix);
 OUTPUT:
  RETVAL
 
+void
+SUB(...)
+PROTOTYPE: ;$
+PREINIT:
+ I32 cxix;
+PPCODE:
+ SU_GET_CONTEXT(0, 0);
+ for (; cxix >= 0; --cxix) {
+  PERL_CONTEXT *cx = cxstack + cxix;
+  switch (CxTYPE(cx)) {
+   default:
+    continue;
+   case CXt_SUB:
+    if (PL_DBsub && cx->blk_sub.cv == GvCV(PL_DBsub))
+     continue;
+    ST(0) = sv_2mortal(newSViv(cxix));
+    XSRETURN(1);
+  }
+ }
+ XSRETURN_UNDEF;
+
+void
+EVAL(...)
+PROTOTYPE: ;$
+PREINIT:
+ I32 cxix;
+PPCODE:
+ SU_GET_CONTEXT(0, 0);
+ for (; cxix >= 0; --cxix) {
+  PERL_CONTEXT *cx = cxstack + cxix;
+  switch (CxTYPE(cx)) {
+   default:
+    continue;
+   case CXt_EVAL:
+    ST(0) = sv_2mortal(newSViv(cxix));
+    XSRETURN(1);
+  }
+ }
+ XSRETURN_UNDEF;
+
+void
+SCOPE(...)
+PROTOTYPE: ;$
+PREINIT:
+ I32 cxix, level;
+PPCODE:
+ SU_GET_LEVEL(0, 0);
+ cxix = cxstack_ix;
+ if (PL_DBsub) {
+  SU_SKIP_DB(cxix);
+  while (cxix > 0) {
+   if (--level < 0)
+    break;
+   --cxix;
+   SU_SKIP_DB(cxix);
+  }
+ } else {
+  cxix -= level;
+  if (cxix < 0)
+   cxix = 0;
+ }
+ ST(0) = sv_2mortal(newSViv(cxix));
+ XSRETURN(1);
+
+void
+CALLER(...)
+PROTOTYPE: ;$
+PREINIT:
+ I32 cxix, level;
+PPCODE:
+ SU_GET_LEVEL(0, 0);
+ for (cxix = cxstack_ix; cxix > 0; --cxix) {
+  PERL_CONTEXT *cx = cxstack + cxix;
+  switch (CxTYPE(cx)) {
+   case CXt_SUB:
+    if (PL_DBsub && cx->blk_sub.cv == GvCV(PL_DBsub))
+     continue;
+   case CXt_EVAL:
+   case CXt_FORMAT:
+    if (--level < 0)
+     goto done;
+    break;
+  }
+ }
+done:
+ ST(0) = sv_2mortal(newSViv(cxix));
+ XSRETURN(1);
+
+void
+want_at(...)
+PROTOTYPE: ;$
+PREINIT:
+ I32 cxix;
+PPCODE:
+ SU_GET_CONTEXT(0, 0);
+ while (cxix > 0) {
+  PERL_CONTEXT *cx = cxstack + cxix--;
+  switch (CxTYPE(cx)) {
+   case CXt_SUB:
+   case CXt_EVAL:
+   case CXt_FORMAT: {
+    I32 gimme = cx->blk_gimme;
+    switch (gimme) {
+     case G_VOID:   XSRETURN_UNDEF; break;
+     case G_SCALAR: XSRETURN_NO;    break;
+     case G_ARRAY:  XSRETURN_YES;   break;
+    }
+    break;
+   }
+  }
+ }
+ XSRETURN_UNDEF;
+
 void
 reap(SV *hook, ...)
 PROTOTYPE: &;$
 PREINIT:
- I32 level = 0;
+ I32 cxix;
  su_ud_reap *ud;
 CODE:
- SU_GET_LEVEL(1);
+ SU_GET_CONTEXT(1, 1);
  Newx(ud, 1, su_ud_reap);
  SU_UD_ORIGIN(ud)  = NULL;
  SU_UD_HANDLER(ud) = su_reap;
  ud->cb = newSVsv(hook);
- su_init(level, ud, 3);
+ su_init(cxix, ud, 3);
 
 void
 localize(SV *sv, SV *val, ...)
 PROTOTYPE: $$;$
 PREINIT:
- I32 level = 0;
+ I32 cxix;
+ I32 size = 3;
  su_ud_localize *ud;
 CODE:
- SU_GET_LEVEL(2);
+ SU_GET_CONTEXT(2, 2);
  Newx(ud, 1, su_ud_localize);
  SU_UD_ORIGIN(ud)  = NULL;
  SU_UD_HANDLER(ud) = su_localize;
- SvREFCNT_inc(sv);
- ud->sv   = sv;
- ud->val  = newSVsv(val);
- ud->elem = NULL;
- su_init(level, ud, 3);
+ su_ud_localize_init(ud, sv, val, NULL);
+#if !SU_HAS_PERL(5, 8, 9)
+ if (ud->type >= SVt_PVGV)
+  size = 6;
+#endif
+ su_init(cxix, ud, size);
 
 void
 localize_elem(SV *sv, SV *elem, SV *val, ...)
 PROTOTYPE: $$$;$
 PREINIT:
- I32 level = 0;
+ I32 cxix;
  su_ud_localize *ud;
 CODE:
- SU_GET_LEVEL(3);
+ if (SvTYPE(sv) >= SVt_PVGV)
+  croak("Can't infer the element localization type from a glob and the value");
+ SU_GET_CONTEXT(3, 3);
  Newx(ud, 1, su_ud_localize);
  SU_UD_ORIGIN(ud)  = NULL;
  SU_UD_HANDLER(ud) = su_localize;
- SvREFCNT_inc(sv);
- ud->sv   = sv;
- ud->val  = newSVsv(val);
- SvREFCNT_inc(elem);
- ud->elem = elem;
- su_init(level, ud, 4);
+ su_ud_localize_init(ud, sv, val, elem);
+ if (ud->type != SVt_PVAV && ud->type != SVt_PVHV) {
+  Safefree(ud);
+  croak("Can't localize an element of something that isn't an array or a hash");
+ }
+ su_init(cxix, ud, 4);
 
 void
 localize_delete(SV *sv, SV *elem, ...)
 PROTOTYPE: $$;$
 PREINIT:
- I32 level = 0;
+ I32 cxix;
+ I32 size = 4;
  su_ud_localize *ud;
 CODE:
- SU_GET_LEVEL(2);
+ SU_GET_CONTEXT(2, 2);
  Newx(ud, 1, su_ud_localize);
  SU_UD_ORIGIN(ud)  = NULL;
  SU_UD_HANDLER(ud) = su_localize;
- SvREFCNT_inc(sv);
- ud->sv   = sv;
- ud->val  = NULL;
- SvREFCNT_inc(elem);
- ud->elem = elem;
- su_init(level, ud, 4);
+ su_ud_localize_init(ud, sv, NULL, elem);
+#if !SU_HAS_PERL(5, 8, 9)
+ if (ud->type >= SVt_PVGV)
+  size = 6;
+#endif
+ su_init(cxix, ud, size);