1 files changed, 476 insertions, 0 deletions

diff --git a/src/civetweb/src/third_party/duktape-1.8.0/src-separate/duk_hthread_stacks.c b/src/civetweb/src/third_party/duktape-1.8.0/src-separate/duk_hthread_stacks.c
new file mode 100644
index 000000000..59b072d92
--- /dev/null
+++ b/src/civetweb/src/third_party/duktape-1.8.0/src-separate/duk_hthread_stacks.c
@@ -0,0 +1,476 @@
+/*
+ *  Manipulation of thread stacks (valstack, callstack, catchstack).
+ *
+ *  Ideally unwinding of stacks should have no side effects, which would
+ *  then favor separate unwinding and shrink check primitives for each
+ *  stack type.  A shrink check may realloc and thus have side effects.
+ *
+ *  However, currently callstack unwinding itself has side effects, as it
+ *  needs to DECREF multiple objects, close environment records, etc.
+ *  Stacks must thus be unwound in the correct order by the caller.
+ *
+ *  (XXX: This should be probably reworked so that there is a shared
+ *  unwind primitive which handles all stacks as requested, and knows
+ *  the proper order for unwinding.)
+ *
+ *  Valstack entries above 'top' are always kept initialized to
+ *  "undefined unused".  Callstack and catchstack entries above 'top'
+ *  are not zeroed and are left as garbage.
+ *
+ *  Value stack handling is mostly a part of the API implementation.
+ */
+
+#include "duk_internal.h"
+
+/* check that there is space for at least one new entry */
+DUK_INTERNAL void duk_hthread_callstack_grow(duk_hthread *thr) {
+	duk_activation *new_ptr;
+	duk_size_t old_size;
+	duk_size_t new_size;
+
+	DUK_ASSERT(thr != NULL);
+	DUK_ASSERT_DISABLE(thr->callstack_top >= 0);   /* avoid warning (unsigned) */
+	DUK_ASSERT(thr->callstack_size >= thr->callstack_top);
+
+	if (thr->callstack_top < thr->callstack_size) {
+		return;
+	}
+
+	old_size = thr->callstack_size;
+	new_size = old_size + DUK_CALLSTACK_GROW_STEP;
+
+	/* this is a bit approximate (errors out before max is reached); this is OK */
+	if (new_size >= thr->callstack_max) {
+		DUK_ERROR_RANGE(thr, DUK_STR_CALLSTACK_LIMIT);
+	}
+
+	DUK_DD(DUK_DDPRINT("growing callstack %ld -> %ld", (long) old_size, (long) new_size));
+
+	/*
+	 *  Note: must use indirect variant of DUK_REALLOC() because underlying
+	 *  pointer may be changed by mark-and-sweep.
+	 */
+
+	DUK_ASSERT(new_size > 0);
+	new_ptr = (duk_activation *) DUK_REALLOC_INDIRECT(thr->heap, duk_hthread_get_callstack_ptr, (void *) thr, sizeof(duk_activation) * new_size);
+	if (!new_ptr) {
+		/* No need for a NULL/zero-size check because new_size > 0) */
+		DUK_ERROR_ALLOC_DEFMSG(thr);
+	}
+	thr->callstack = new_ptr;
+	thr->callstack_size = new_size;
+
+	/* note: any entries above the callstack top are garbage and not zeroed */
+}
+
+DUK_INTERNAL void duk_hthread_callstack_shrink_check(duk_hthread *thr) {
+	duk_size_t new_size;
+	duk_activation *p;
+
+	DUK_ASSERT(thr != NULL);
+	DUK_ASSERT_DISABLE(thr->callstack_top >= 0);  /* avoid warning (unsigned) */
+	DUK_ASSERT(thr->callstack_size >= thr->callstack_top);
+
+	if (thr->callstack_size - thr->callstack_top < DUK_CALLSTACK_SHRINK_THRESHOLD) {
+		return;
+	}
+
+	new_size = thr->callstack_top + DUK_CALLSTACK_SHRINK_SPARE;
+	DUK_ASSERT(new_size >= thr->callstack_top);
+
+	DUK_DD(DUK_DDPRINT("shrinking callstack %ld -> %ld", (long) thr->callstack_size, (long) new_size));
+
+	/*
+	 *  Note: must use indirect variant of DUK_REALLOC() because underlying
+	 *  pointer may be changed by mark-and-sweep.
+	 */
+
+	/* shrink failure is not fatal */
+	p = (duk_activation *) DUK_REALLOC_INDIRECT(thr->heap, duk_hthread_get_callstack_ptr, (void *) thr, sizeof(duk_activation) * new_size);
+	if (p) {
+		thr->callstack = p;
+		thr->callstack_size = new_size;
+	} else {
+		/* Because new_size != 0, if condition doesn't need to be
+		 * (p != NULL || new_size == 0).
+		 */
+		DUK_ASSERT(new_size != 0);
+		DUK_D(DUK_DPRINT("callstack shrink failed, ignoring"));
+	}
+
+	/* note: any entries above the callstack top are garbage and not zeroed */
+}
+
+DUK_INTERNAL void duk_hthread_callstack_unwind(duk_hthread *thr, duk_size_t new_top) {
+	duk_size_t idx;
+
+	DUK_DDD(DUK_DDDPRINT("unwind callstack top of thread %p from %ld to %ld",
+	                     (void *) thr,
+	                     (thr != NULL ? (long) thr->callstack_top : (long) -1),
+	                     (long) new_top));
+
+	DUK_ASSERT(thr);
+	DUK_ASSERT(thr->heap);
+	DUK_ASSERT_DISABLE(new_top >= 0);  /* unsigned */
+	DUK_ASSERT((duk_size_t) new_top <= thr->callstack_top);  /* cannot grow */
+
+	/*
+	 *  The loop below must avoid issues with potential callstack
+	 *  reallocations.  A resize (and other side effects) may happen
+	 *  e.g. due to finalizer/errhandler calls caused by a refzero or
+	 *  mark-and-sweep.  Arbitrary finalizers may run, because when
+	 *  an environment record is refzero'd, it may refer to arbitrary
+	 *  values which also become refzero'd.
+	 *
+	 *  So, the pointer 'p' is re-looked-up below whenever a side effect
+	 *  might have changed it.
+	 */
+
+	idx = thr->callstack_top;
+	while (idx > new_top) {
+		duk_activation *act;
+		duk_hobject *func;
+#ifdef DUK_USE_REFERENCE_COUNTING
+		duk_hobject *tmp;
+#endif
+#ifdef DUK_USE_DEBUGGER_SUPPORT
+		duk_heap *heap;
+#endif
+
+		idx--;
+		DUK_ASSERT_DISABLE(idx >= 0);  /* unsigned */
+		DUK_ASSERT((duk_size_t) idx < thr->callstack_size);  /* true, despite side effect resizes */
+
+		act = thr->callstack + idx;
+		/* With lightfuncs, act 'func' may be NULL */
+
+#ifdef DUK_USE_NONSTD_FUNC_CALLER_PROPERTY
+		/*
+		 *  Restore 'caller' property for non-strict callee functions.
+		 */
+
+		func = DUK_ACT_GET_FUNC(act);
+		if (func != NULL && !DUK_HOBJECT_HAS_STRICT(func)) {
+			duk_tval *tv_caller;
+			duk_tval tv_tmp;
+			duk_hobject *h_tmp;
+
+			tv_caller = duk_hobject_find_existing_entry_tval_ptr(thr->heap, func, DUK_HTHREAD_STRING_CALLER(thr));
+
+			/* The act->prev_caller should only be set if the entry for 'caller'
+			 * exists (as it is only set in that case, and the property is not
+			 * configurable), but handle all the cases anyway.
+			 */
+
+			if (tv_caller) {
+				DUK_TVAL_SET_TVAL(&tv_tmp, tv_caller);
+				if (act->prev_caller) {
+					/* Just transfer the refcount from act->prev_caller to tv_caller,
+					 * so no need for a refcount update.  This is the expected case.
+					 */
+					DUK_TVAL_SET_OBJECT(tv_caller, act->prev_caller);
+					act->prev_caller = NULL;
+				} else {
+					DUK_TVAL_SET_NULL(tv_caller);   /* no incref needed */
+					DUK_ASSERT(act->prev_caller == NULL);
+				}
+				DUK_TVAL_DECREF(thr, &tv_tmp);  /* side effects */
+			} else {
+				h_tmp = act->prev_caller;
+				if (h_tmp) {
+					act->prev_caller = NULL;
+					DUK_HOBJECT_DECREF(thr, h_tmp);  /* side effects */
+				}
+			}
+			act = thr->callstack + idx;  /* avoid side effects */
+			DUK_ASSERT(act->prev_caller == NULL);
+		}
+#endif
+
+		/*
+		 *  Unwind debugger state.  If we unwind while stepping
+		 *  (either step over or step into), pause execution.
+		 */
+
+#if defined(DUK_USE_DEBUGGER_SUPPORT)
+		heap = thr->heap;
+		if (heap->dbg_step_thread == thr &&
+		    heap->dbg_step_csindex == idx) {
+			/* Pause for all step types: step into, step over, step out.
+			 * This is the only place explicitly handling a step out.
+			 */
+			DUK_HEAP_SET_PAUSED(heap);
+			DUK_ASSERT(heap->dbg_step_thread == NULL);
+		}
+#endif
+
+		/*
+		 *  Close environment record(s) if they exist.
+		 *
+		 *  Only variable environments are closed.  If lex_env != var_env, it
+		 *  cannot currently contain any register bound declarations.
+		 *
+		 *  Only environments created for a NEWENV function are closed.  If an
+		 *  environment is created for e.g. an eval call, it must not be closed.
+		 */
+
+		func = DUK_ACT_GET_FUNC(act);
+		if (func != NULL && !DUK_HOBJECT_HAS_NEWENV(func)) {
+			DUK_DDD(DUK_DDDPRINT("skip closing environments, envs not owned by this activation"));
+			goto skip_env_close;
+		}
+		/* func is NULL for lightfunc */
+
+		DUK_ASSERT(act->lex_env == act->var_env);
+		if (act->var_env != NULL) {
+			DUK_DDD(DUK_DDDPRINT("closing var_env record %p -> %!O",
+			                     (void *) act->var_env, (duk_heaphdr *) act->var_env));
+			duk_js_close_environment_record(thr, act->var_env, func, act->idx_bottom);
+			act = thr->callstack + idx;  /* avoid side effect issues */
+		}
+
+#if 0
+		if (act->lex_env != NULL) {
+			if (act->lex_env == act->var_env) {
+				/* common case, already closed, so skip */
+				DUK_DD(DUK_DDPRINT("lex_env and var_env are the same and lex_env "
+				                   "already closed -> skip closing lex_env"));
+				;
+			} else {
+				DUK_DD(DUK_DDPRINT("closing lex_env record %p -> %!O",
+				                   (void *) act->lex_env, (duk_heaphdr *) act->lex_env));
+				duk_js_close_environment_record(thr, act->lex_env, DUK_ACT_GET_FUNC(act), act->idx_bottom);
+				act = thr->callstack + idx;  /* avoid side effect issues */
+			}
+		}
+#endif
+
+		DUK_ASSERT((act->lex_env == NULL) ||
+		           ((duk_hobject_find_existing_entry_tval_ptr(thr->heap, act->lex_env, DUK_HTHREAD_STRING_INT_CALLEE(thr)) == NULL) &&
+		            (duk_hobject_find_existing_entry_tval_ptr(thr->heap, act->lex_env, DUK_HTHREAD_STRING_INT_VARMAP(thr)) == NULL) &&
+		            (duk_hobject_find_existing_entry_tval_ptr(thr->heap, act->lex_env, DUK_HTHREAD_STRING_INT_THREAD(thr)) == NULL) &&
+		            (duk_hobject_find_existing_entry_tval_ptr(thr->heap, act->lex_env, DUK_HTHREAD_STRING_INT_REGBASE(thr)) == NULL)));
+
+		DUK_ASSERT((act->var_env == NULL) ||
+		           ((duk_hobject_find_existing_entry_tval_ptr(thr->heap, act->var_env, DUK_HTHREAD_STRING_INT_CALLEE(thr)) == NULL) &&
+		            (duk_hobject_find_existing_entry_tval_ptr(thr->heap, act->var_env, DUK_HTHREAD_STRING_INT_VARMAP(thr)) == NULL) &&
+		            (duk_hobject_find_existing_entry_tval_ptr(thr->heap, act->var_env, DUK_HTHREAD_STRING_INT_THREAD(thr)) == NULL) &&
+		            (duk_hobject_find_existing_entry_tval_ptr(thr->heap, act->var_env, DUK_HTHREAD_STRING_INT_REGBASE(thr)) == NULL)));
+
+	 skip_env_close:
+
+		/*
+		 *  Update preventcount
+		 */
+
+		if (act->flags & DUK_ACT_FLAG_PREVENT_YIELD) {
+			DUK_ASSERT(thr->callstack_preventcount >= 1);
+			thr->callstack_preventcount--;
+		}
+
+		/*
+		 *  Reference count updates
+		 *
+		 *  Note: careful manipulation of refcounts.  The top is
+		 *  not updated yet, so all the activations are reachable
+		 *  for mark-and-sweep (which may be triggered by decref).
+		 *  However, the pointers are NULL so this is not an issue.
+		 */
+
+#ifdef DUK_USE_REFERENCE_COUNTING
+		tmp = act->var_env;
+#endif
+		act->var_env = NULL;
+#ifdef DUK_USE_REFERENCE_COUNTING
+		DUK_HOBJECT_DECREF_ALLOWNULL(thr, tmp);
+		act = thr->callstack + idx;  /* avoid side effect issues */
+#endif
+
+#ifdef DUK_USE_REFERENCE_COUNTING
+		tmp = act->lex_env;
+#endif
+		act->lex_env = NULL;
+#ifdef DUK_USE_REFERENCE_COUNTING
+		DUK_HOBJECT_DECREF_ALLOWNULL(thr, tmp);
+		act = thr->callstack + idx;  /* avoid side effect issues */
+#endif
+
+		/* Note: this may cause a corner case situation where a finalizer
+		 * may see a currently reachable activation whose 'func' is NULL.
+		 */
+#ifdef DUK_USE_REFERENCE_COUNTING
+		tmp = DUK_ACT_GET_FUNC(act);
+#endif
+		act->func = NULL;
+#ifdef DUK_USE_REFERENCE_COUNTING
+		DUK_HOBJECT_DECREF_ALLOWNULL(thr, tmp);
+		act = thr->callstack + idx;  /* avoid side effect issues */
+		DUK_UNREF(act);
+#endif
+	}
+
+	thr->callstack_top = new_top;
+
+	/*
+	 *  We could clear the book-keeping variables for the topmost activation,
+	 *  but don't do so now.
+	 */
+#if 0
+	if (thr->callstack_top > 0) {
+		duk_activation *act = thr->callstack + thr->callstack_top - 1;
+		act->idx_retval = 0;
+	}
+#endif
+
+	/* Note: any entries above the callstack top are garbage and not zeroed.
+	 * Also topmost activation idx_retval is garbage (not zeroed), and must
+	 * be ignored.
+	 */
+}
+
+DUK_INTERNAL void duk_hthread_catchstack_grow(duk_hthread *thr) {
+	duk_catcher *new_ptr;
+	duk_size_t old_size;
+	duk_size_t new_size;
+
+	DUK_ASSERT(thr != NULL);
+	DUK_ASSERT_DISABLE(thr->catchstack_top);  /* avoid warning (unsigned) */
+	DUK_ASSERT(thr->catchstack_size >= thr->catchstack_top);
+
+	if (thr->catchstack_top < thr->catchstack_size) {
+		return;
+	}
+
+	old_size = thr->catchstack_size;
+	new_size = old_size + DUK_CATCHSTACK_GROW_STEP;
+
+	/* this is a bit approximate (errors out before max is reached); this is OK */
+	if (new_size >= thr->catchstack_max) {
+		DUK_ERROR_RANGE(thr, DUK_STR_CATCHSTACK_LIMIT);
+	}
+
+	DUK_DD(DUK_DDPRINT("growing catchstack %ld -> %ld", (long) old_size, (long) new_size));
+
+	/*
+	 *  Note: must use indirect variant of DUK_REALLOC() because underlying
+	 *  pointer may be changed by mark-and-sweep.
+	 */
+
+	DUK_ASSERT(new_size > 0);
+	new_ptr = (duk_catcher *) DUK_REALLOC_INDIRECT(thr->heap, duk_hthread_get_catchstack_ptr, (void *) thr, sizeof(duk_catcher) * new_size);
+	if (!new_ptr) {
+		/* No need for a NULL/zero-size check because new_size > 0) */
+		DUK_ERROR_ALLOC_DEFMSG(thr);
+	}
+	thr->catchstack = new_ptr;
+	thr->catchstack_size = new_size;
+
+	/* note: any entries above the catchstack top are garbage and not zeroed */
+}
+
+DUK_INTERNAL void duk_hthread_catchstack_shrink_check(duk_hthread *thr) {
+	duk_size_t new_size;
+	duk_catcher *p;
+
+	DUK_ASSERT(thr != NULL);
+	DUK_ASSERT_DISABLE(thr->catchstack_top >= 0);  /* avoid warning (unsigned) */
+	DUK_ASSERT(thr->catchstack_size >= thr->catchstack_top);
+
+	if (thr->catchstack_size - thr->catchstack_top < DUK_CATCHSTACK_SHRINK_THRESHOLD) {
+		return;
+	}
+
+	new_size = thr->catchstack_top + DUK_CATCHSTACK_SHRINK_SPARE;
+	DUK_ASSERT(new_size >= thr->catchstack_top);
+
+	DUK_DD(DUK_DDPRINT("shrinking catchstack %ld -> %ld", (long) thr->catchstack_size, (long) new_size));
+
+	/*
+	 *  Note: must use indirect variant of DUK_REALLOC() because underlying
+	 *  pointer may be changed by mark-and-sweep.
+	 */
+
+	/* shrink failure is not fatal */
+	p = (duk_catcher *) DUK_REALLOC_INDIRECT(thr->heap, duk_hthread_get_catchstack_ptr, (void *) thr, sizeof(duk_catcher) * new_size);
+	if (p) {
+		thr->catchstack = p;
+		thr->catchstack_size = new_size;
+	} else {
+		/* Because new_size != 0, if condition doesn't need to be
+		 * (p != NULL || new_size == 0).
+		 */
+		DUK_ASSERT(new_size != 0);
+		DUK_D(DUK_DPRINT("catchstack shrink failed, ignoring"));
+	}
+
+	/* note: any entries above the catchstack top are garbage and not zeroed */
+}
+
+DUK_INTERNAL void duk_hthread_catchstack_unwind(duk_hthread *thr, duk_size_t new_top) {
+	duk_size_t idx;
+
+	DUK_DDD(DUK_DDDPRINT("unwind catchstack top of thread %p from %ld to %ld",
+	                     (void *) thr,
+	                     (thr != NULL ? (long) thr->catchstack_top : (long) -1),
+	                     (long) new_top));
+
+	DUK_ASSERT(thr);
+	DUK_ASSERT(thr->heap);
+	DUK_ASSERT_DISABLE(new_top >= 0);  /* unsigned */
+	DUK_ASSERT((duk_size_t) new_top <= thr->catchstack_top);  /* cannot grow */
+
+	/*
+	 *  Since there are no references in the catcher structure,
+	 *  unwinding is quite simple.  The only thing we need to
+	 *  look out for is popping a possible lexical environment
+	 *  established for an active catch clause.
+	 */
+
+	idx = thr->catchstack_top;
+	while (idx > new_top) {
+		duk_catcher *p;
+		duk_activation *act;
+		duk_hobject *env;
+
+		idx--;
+		DUK_ASSERT_DISABLE(idx >= 0);  /* unsigned */
+		DUK_ASSERT((duk_size_t) idx < thr->catchstack_size);
+
+		p = thr->catchstack + idx;
+
+		if (DUK_CAT_HAS_LEXENV_ACTIVE(p)) {
+			DUK_DDD(DUK_DDDPRINT("unwinding catchstack idx %ld, callstack idx %ld, callstack top %ld: lexical environment active",
+			                     (long) idx, (long) p->callstack_index, (long) thr->callstack_top));
+
+			/* XXX: Here we have a nasty dependency: the need to manipulate
+			 * the callstack means that catchstack must always be unwound by
+			 * the caller before unwinding the callstack.  This should be fixed
+			 * later.
+			 */
+
+			/* Note that multiple catchstack entries may refer to the same
+			 * callstack entry.
+			 */
+			act = thr->callstack + p->callstack_index;
+			DUK_ASSERT(act >= thr->callstack);
+			DUK_ASSERT(act < thr->callstack + thr->callstack_top);
+
+			DUK_DDD(DUK_DDDPRINT("catchstack_index=%ld, callstack_index=%ld, lex_env=%!iO",
+			                     (long) idx, (long) p->callstack_index,
+			                     (duk_heaphdr *) act->lex_env));
+
+			env = act->lex_env;             /* current lex_env of the activation (created for catcher) */
+			DUK_ASSERT(env != NULL);        /* must be, since env was created when catcher was created */
+			act->lex_env = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, env);  /* prototype is lex_env before catcher created */
+			DUK_HOBJECT_DECREF(thr, env);
+
+			/* There is no need to decref anything else than 'env': if 'env'
+			 * becomes unreachable, refzero will handle decref'ing its prototype.
+			 */
+		}
+	}
+
+	thr->catchstack_top = new_top;
+
+	/* note: any entries above the catchstack top are garbage and not zeroed */
+}