DUK_INTERNAL duk_bool_t duk_js_instanceof(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y) {
duk_context *ctx = (duk_context *) thr;
duk_hobject *func;
duk_hobject *val;
duk_hobject *proto;
duk_uint_t sanity;
/*
* Get the values onto the stack first. It would be possible to cover
* some normal cases without resorting to the value stack.
*
* The right hand side could be a light function (as they generally
* behave like objects). Light functions never have a 'prototype'
* property so E5.1 Section 15.3.5.3 step 3 always throws a TypeError.
* Using duk_require_hobject() is thus correct (except for error msg).
*/
duk_push_tval(ctx, tv_x);
duk_push_tval(ctx, tv_y);
func = duk_require_hobject(ctx, -1);
/*
* For bound objects, [[HasInstance]] just calls the target function
* [[HasInstance]]. If that is again a bound object, repeat until
* we find a non-bound Function object.
*/
/* XXX: this bound function resolution also happens elsewhere,
* move into a shared helper.
*/
sanity = DUK_HOBJECT_BOUND_CHAIN_SANITY;
do {
/* check func supports [[HasInstance]] (this is checked for every function
* in the bound chain, including the final one)
*/
if (!DUK_HOBJECT_IS_CALLABLE(func)) {
/*
* Note: of native Ecmascript objects, only Function instances
* have a [[HasInstance]] internal property. Custom objects might
* also have it, but not in current implementation.
*
* XXX: add a separate flag, DUK_HOBJECT_FLAG_ALLOW_INSTANCEOF?
*/
DUK_ERROR_TYPE(thr, "invalid instanceof rval");
}
if (!DUK_HOBJECT_HAS_BOUND(func)) {
break;
}
/* [ ... lval rval ] */
duk_get_prop_stridx(ctx, -1, DUK_STRIDX_INT_TARGET); /* -> [ ... lval rval new_rval ] */
duk_replace(ctx, -1); /* -> [ ... lval new_rval ] */
func = duk_require_hobject(ctx, -1);
/* func support for [[HasInstance]] checked in the beginning of the loop */
} while (--sanity > 0);
if (sanity == 0) {
DUK_ERROR_RANGE(thr, DUK_STR_BOUND_CHAIN_LIMIT);
}
/*
* 'func' is now a non-bound object which supports [[HasInstance]]
* (which here just means DUK_HOBJECT_FLAG_CALLABLE). Move on
* to execute E5 Section 15.3.5.3.
*/
DUK_ASSERT(!DUK_HOBJECT_HAS_BOUND(func));
DUK_ASSERT(DUK_HOBJECT_IS_CALLABLE(func));
/* [ ... lval rval(func) ] */
/* Handle lightfuncs through object coercion for now. */
/* XXX: direct implementation */
val = duk_get_hobject_or_lfunc_coerce(ctx, -2);
if (!val) {
goto pop_and_false;
}
duk_get_prop_stridx(ctx, -1, DUK_STRIDX_PROTOTYPE); /* -> [ ... lval rval rval.prototype ] */
proto = duk_require_hobject(ctx, -1);
duk_pop(ctx); /* -> [ ... lval rval ] */
DUK_ASSERT(val != NULL);
#if defined(DUK_USE_ES6_PROXY)
val = duk_hobject_resolve_proxy_target(thr, val);
DUK_ASSERT(val != NULL);
#endif
sanity = DUK_HOBJECT_PROTOTYPE_CHAIN_SANITY;
do {
/*
* Note: prototype chain is followed BEFORE first comparison. This
* means that the instanceof lval is never itself compared to the
* rval.prototype property. This is apparently intentional, see E5
* Section 15.3.5.3, step 4.a.
*
* Also note:
*
* js> (function() {}) instanceof Function
* true
* js> Function instanceof Function
* true
*
* For the latter, h_proto will be Function.prototype, which is the
* built-in Function prototype. Because Function.[[Prototype]] is
* also the built-in Function prototype, the result is true.
*/
DUK_ASSERT(val != NULL);
val = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, val);
if (!val) {
goto pop_and_false;
}
DUK_ASSERT(val != NULL);
#if defined(DUK_USE_ES6_PROXY)
val = duk_hobject_resolve_proxy_target(thr, val);
#endif
if (val == proto) {
goto pop_and_true;
}
/* follow prototype chain */
} while (--sanity > 0);
if (sanity == 0) {
DUK_ERROR_RANGE(thr, DUK_STR_PROTOTYPE_CHAIN_LIMIT);
}
DUK_UNREACHABLE();
pop_and_false:
duk_pop_2(ctx);
return 0;
pop_and_true:
duk_pop_2(ctx);
return 1;
}
DUK_LOCAL void duk__refcount_finalize_hobject(duk_hthread *thr, duk_hobject *h) {
duk_uint_fast32_t i;
DUK_ASSERT(h);
DUK_ASSERT(DUK_HEAPHDR_GET_TYPE((duk_heaphdr *) h) == DUK_HTYPE_OBJECT);
/* XXX: better to get base and walk forwards? */
for (i = 0; i < (duk_uint_fast32_t) DUK_HOBJECT_GET_ENEXT(h); i++) {
duk_hstring *key = DUK_HOBJECT_E_GET_KEY(thr->heap, h, i);
if (!key) {
continue;
}
duk_heaphdr_decref(thr, (duk_heaphdr *) key);
if (DUK_HOBJECT_E_SLOT_IS_ACCESSOR(thr->heap, h, i)) {
duk_heaphdr_decref_allownull(thr, (duk_heaphdr *) DUK_HOBJECT_E_GET_VALUE_GETTER(thr->heap, h, i));
duk_heaphdr_decref_allownull(thr, (duk_heaphdr *) DUK_HOBJECT_E_GET_VALUE_SETTER(thr->heap, h, i));
} else {
duk_tval_decref(thr, DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, h, i));
}
}
for (i = 0; i < (duk_uint_fast32_t) DUK_HOBJECT_GET_ASIZE(h); i++) {
duk_tval_decref(thr, DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, h, i));
}
/* hash part is a 'weak reference' and does not contribute */
duk_heaphdr_decref_allownull(thr, (duk_heaphdr *) DUK_HOBJECT_GET_PROTOTYPE(thr->heap, h));
if (DUK_HOBJECT_IS_COMPILEDFUNCTION(h)) {
duk_hcompiledfunction *f = (duk_hcompiledfunction *) h;
duk_tval *tv, *tv_end;
duk_hobject **funcs, **funcs_end;
DUK_ASSERT(DUK_HCOMPILEDFUNCTION_GET_DATA(thr->heap, f) != NULL); /* compiled functions must be created 'atomically' */
tv = DUK_HCOMPILEDFUNCTION_GET_CONSTS_BASE(thr->heap, f);
tv_end = DUK_HCOMPILEDFUNCTION_GET_CONSTS_END(thr->heap, f);
while (tv < tv_end) {
duk_tval_decref(thr, tv);
tv++;
}
funcs = DUK_HCOMPILEDFUNCTION_GET_FUNCS_BASE(thr->heap, f);
funcs_end = DUK_HCOMPILEDFUNCTION_GET_FUNCS_END(thr->heap, f);
while (funcs < funcs_end) {
duk_heaphdr_decref(thr, (duk_heaphdr *) *funcs);
funcs++;
}
duk_heaphdr_decref(thr, (duk_heaphdr *) DUK_HCOMPILEDFUNCTION_GET_DATA(thr->heap, f));
} else if (DUK_HOBJECT_IS_NATIVEFUNCTION(h)) {
duk_hnativefunction *f = (duk_hnativefunction *) h;
DUK_UNREF(f);
/* nothing to finalize */
} else if (DUK_HOBJECT_IS_BUFFEROBJECT(h)) {
duk_hbufferobject *b = (duk_hbufferobject *) h;
if (b->buf) {
duk_heaphdr_decref(thr, (duk_heaphdr *) b->buf);
}
} else if (DUK_HOBJECT_IS_THREAD(h)) {
duk_hthread *t = (duk_hthread *) h;
duk_tval *tv;
tv = t->valstack;
while (tv < t->valstack_top) {
duk_tval_decref(thr, tv);
tv++;
}
for (i = 0; i < (duk_uint_fast32_t) t->callstack_top; i++) {
duk_activation *act = t->callstack + i;
duk_heaphdr_decref_allownull(thr, (duk_heaphdr *) DUK_ACT_GET_FUNC(act));
duk_heaphdr_decref_allownull(thr, (duk_heaphdr *) act->var_env);
duk_heaphdr_decref_allownull(thr, (duk_heaphdr *) act->lex_env);
#ifdef DUK_USE_NONSTD_FUNC_CALLER_PROPERTY
duk_heaphdr_decref_allownull(thr, (duk_heaphdr *) act->prev_caller);
#endif
}
#if 0 /* nothing now */
for (i = 0; i < (duk_uint_fast32_t) t->catchstack_top; i++) {
duk_catcher *cat = t->catchstack + i;
}
#endif
for (i = 0; i < DUK_NUM_BUILTINS; i++) {
duk_heaphdr_decref_allownull(thr, (duk_heaphdr *) t->builtins[i]);
}
duk_heaphdr_decref_allownull(thr, (duk_heaphdr *) t->resumer);
}
}
