+/* --- Context operations -------------------------------------------------- */
+
+/* Remove sequences of BLOCKs having DB for stash, followed by a SUB context
+ * for the debugger callback. */
+
+static I32 su_context_skip_db(pTHX_ I32 cxix) {
+#define su_context_skip_db(C) su_context_skip_db(aTHX_ (C))
+ I32 i;
+
+ if (!PL_DBsub)
+ return cxix;
+
+ for (i = cxix; i > 0; --i) {
+ PERL_CONTEXT *cx = cxstack + i;
+
+ switch (CxTYPE(cx)) {
+#if SU_HAS_PERL(5, 17, 1)
+ case CXt_LOOP_PLAIN:
+#endif
+ case CXt_BLOCK:
+ if (cx->blk_oldcop && CopSTASH(cx->blk_oldcop) == GvSTASH(PL_DBgv))
+ continue;
+ break;
+ case CXt_SUB:
+ if (cx->blk_sub.cv == GvCV(PL_DBsub)) {
+ cxix = i - 1;
+ continue;
+ }
+ break;
+ default:
+ break;
+ }
+
+ break;
+ }
+
+ return cxix;
+}
+
+
+static I32 su_context_normalize_up(pTHX_ I32 cxix) {
+#define su_context_normalize_up(C) su_context_normalize_up(aTHX_ (C))
+ PERL_CONTEXT *cx;
+
+ if (cxix <= 0)
+ return 0;
+
+ cx = cxstack + cxix;
+ if (CxTYPE(cx) == CXt_BLOCK) {
+ PERL_CONTEXT *prev = cx - 1;
+
+ switch (CxTYPE(prev)) {
+#if SU_HAS_PERL(5, 10, 0)
+ case CXt_GIVEN:
+ case CXt_WHEN:
+#endif
+#if SU_HAS_PERL(5, 11, 0)
+ /* That's the only subcategory that can cause an extra BLOCK context */
+ case CXt_LOOP_PLAIN:
+#else
+ case CXt_LOOP:
+#endif
+ if (cx->blk_oldcop == prev->blk_oldcop)
+ return cxix - 1;
+ break;
+ case CXt_SUBST:
+ if (cx->blk_oldcop && OpSIBLING(cx->blk_oldcop)
+ && OpSIBLING(cx->blk_oldcop)->op_type == OP_SUBST)
+ return cxix - 1;
+ break;
+ }
+ }
+
+ return cxix;
+}
+
+static I32 su_context_normalize_down(pTHX_ I32 cxix) {
+#define su_context_normalize_down(C) su_context_normalize_down(aTHX_ (C))
+ PERL_CONTEXT *next;
+
+ if (cxix >= cxstack_ix)
+ return cxstack_ix;
+
+ next = cxstack + cxix + 1;
+ if (CxTYPE(next) == CXt_BLOCK) {
+ PERL_CONTEXT *cx = next - 1;
+
+ switch (CxTYPE(cx)) {
+#if SU_HAS_PERL(5, 10, 0)
+ case CXt_GIVEN:
+ case CXt_WHEN:
+#endif
+#if SU_HAS_PERL(5, 11, 0)
+ /* That's the only subcategory that can cause an extra BLOCK context */
+ case CXt_LOOP_PLAIN:
+#else
+ case CXt_LOOP:
+#endif
+ if (cx->blk_oldcop == next->blk_oldcop)
+ return cxix + 1;
+ break;
+ case CXt_SUBST:
+ if (next->blk_oldcop && OpSIBLING(next->blk_oldcop)
+ && OpSIBLING(next->blk_oldcop)->op_type == OP_SUBST)
+ return cxix + 1;
+ break;
+ }
+ }
+
+ return cxix;
+}
+
+#define su_context_here() su_context_normalize_up(su_context_skip_db(cxstack_ix))
+
+static I32 su_context_gimme(pTHX_ I32 cxix) {
+#define su_context_gimme(C) su_context_gimme(aTHX_ (C))
+ I32 i;
+
+ for (i = cxix; i >= 0; --i) {
+ PERL_CONTEXT *cx = cxstack + i;
+
+ switch (CxTYPE(cx)) {
+ /* gimme is always G_ARRAY for loop contexts. */
+#if SU_HAS_PERL(5, 11, 0)
+ case CXt_LOOP_FOR:
+ case CXt_LOOP_PLAIN:
+ case CXt_LOOP_LAZYSV:
+ case CXt_LOOP_LAZYIV:
+#else
+ case CXt_LOOP:
+#endif
+ case CXt_SUBST: {
+ const COP *cop = cx->blk_oldcop;
+ if (cop && OpSIBLING(cop)) {
+ switch (OpSIBLING(cop)->op_flags & OPf_WANT) {
+ case OPf_WANT_VOID:
+ return G_VOID;
+ case OPf_WANT_SCALAR:
+ return G_SCALAR;
+ case OPf_WANT_LIST:
+ return G_ARRAY;
+ default:
+ break;
+ }
+ }
+ break;
+ }
+ default:
+ return CxGIMME(cx);
+ break;
+ }
+ }
+
+ return G_VOID;
+}
+
+/* --- Global setup/teardown ----------------------------------------------- */
+
+static VOL U32 su_initialized = 0;
+
+static void su_global_teardown(pTHX_ void *root) {
+ if (!su_initialized)
+ return;
+
+#if SU_MULTIPLICITY
+ if (aTHX != root)
+ return;
+#endif
+
+ SU_LOCK(&su_uid_seq_counter_mutex);
+ PerlMemShared_free(su_uid_seq_counter.seqs);
+ su_uid_seq_counter.size = 0;
+ SU_UNLOCK(&su_uid_seq_counter_mutex);
+
+ MUTEX_DESTROY(&su_uid_seq_counter_mutex);
+
+ su_initialized = 0;
+
+ return;
+}
+
+XS(XS_Scope__Upper_unwind);
+XS(XS_Scope__Upper_yield);
+XS(XS_Scope__Upper_leave);
+
+#if SU_HAS_PERL(5, 9, 0)
+# define SU_XS_FILE_TYPE const char
+#else
+# define SU_XS_FILE_TYPE char
+#endif
+
+static void su_global_setup(pTHX_ SU_XS_FILE_TYPE *file) {
+#define su_global_setup(F) su_global_setup(aTHX_ (F))
+ HV *stash;
+
+ if (su_initialized)
+ return;
+
+ MUTEX_INIT(&su_uid_seq_counter_mutex);
+
+ SU_LOCK(&su_uid_seq_counter_mutex);
+ su_uid_seq_counter.seqs = NULL;
+ su_uid_seq_counter.size = 0;
+ SU_UNLOCK(&su_uid_seq_counter_mutex);
+
+ 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);
+ newXSproto("Scope::Upper::yield", XS_Scope__Upper_yield, file, NULL);
+ newXSproto("Scope::Upper::leave", XS_Scope__Upper_leave, file, NULL);
+
+#if SU_MULTIPLICITY
+ call_atexit(su_global_teardown, aTHX);
+#else
+ call_atexit(su_global_teardown, NULL);
+#endif
+
+ su_initialized = 1;
+
+ return;
+}
+