DUK_INTERNAL void duk_resolve_nonbound_function(duk_context *ctx) {
duk_uint_t sanity;
duk_tval *tv;
sanity = DUK_HOBJECT_BOUND_CHAIN_SANITY;
do {
tv = DUK_GET_TVAL_NEGIDX(ctx, -1);
if (DUK_TVAL_IS_LIGHTFUNC(tv)) {
/* Lightweight function: never bound, so terminate. */
break;
} else if (DUK_TVAL_IS_OBJECT(tv)) {
duk_hobject *func;
func = DUK_TVAL_GET_OBJECT(tv);
DUK_ASSERT(func != NULL);
if (!DUK_HOBJECT_IS_CALLABLE(func) || !DUK_HOBJECT_HAS_BOUNDFUNC(func)) {
break;
}
duk_get_prop_stridx_short(ctx, -1, DUK_STRIDX_INT_TARGET);
duk_replace(ctx, -2);
} else {
break;
}
} while (--sanity > 0);
}
DUK_INTERNAL duk_hstring *duk_js_typeof(duk_hthread *thr, duk_tval *tv_x) {
duk_small_int_t stridx = 0;
switch (DUK_TVAL_GET_TAG(tv_x)) {
case DUK_TAG_UNDEFINED: {
stridx = DUK_STRIDX_LC_UNDEFINED;
break;
}
case DUK_TAG_NULL: {
/* Note: not a typo, "object" is returned for a null value */
stridx = DUK_STRIDX_LC_OBJECT;
break;
}
case DUK_TAG_BOOLEAN: {
stridx = DUK_STRIDX_LC_BOOLEAN;
break;
}
case DUK_TAG_POINTER: {
/* implementation specific */
stridx = DUK_STRIDX_LC_POINTER;
break;
}
case DUK_TAG_STRING: {
stridx = DUK_STRIDX_LC_STRING;
break;
}
case DUK_TAG_OBJECT: {
duk_hobject *obj = DUK_TVAL_GET_OBJECT(tv_x);
DUK_ASSERT(obj != NULL);
if (DUK_HOBJECT_IS_CALLABLE(obj)) {
stridx = DUK_STRIDX_LC_FUNCTION;
} else {
stridx = DUK_STRIDX_LC_OBJECT;
}
break;
}
case DUK_TAG_BUFFER: {
/* implementation specific */
stridx = DUK_STRIDX_LC_BUFFER;
break;
}
case DUK_TAG_LIGHTFUNC: {
stridx = DUK_STRIDX_LC_FUNCTION;
break;
}
#if defined(DUK_USE_FASTINT)
case DUK_TAG_FASTINT:
#endif
default: {
/* number */
DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_x));
stridx = DUK_STRIDX_LC_NUMBER;
break;
}
}
DUK_ASSERT(stridx >= 0 && stridx < DUK_HEAP_NUM_STRINGS);
return DUK_HTHREAD_GET_STRING(thr, stridx);
}
/*
* IsCallable() (E5 Section 9.11)
*
* XXX: API equivalent is a separate implementation now, and this has
* currently no callers.
*/
#if 0 /* unused */
DUK_INTERNAL duk_bool_t duk_js_iscallable(duk_tval *tv_x) {
duk_hobject *obj;
if (!DUK_TVAL_IS_OBJECT(tv_x)) {
return 0;
}
obj = DUK_TVAL_GET_OBJECT(tv_x);
DUK_ASSERT(obj != NULL);
return DUK_HOBJECT_IS_CALLABLE(obj);
}
duk_hstring *duk_js_typeof(duk_hthread *thr, duk_tval *tv_x) {
int idx = 0;
switch (DUK_TVAL_GET_TAG(tv_x)) {
case DUK_TAG_UNDEFINED: {
idx = DUK_STRIDX_LC_UNDEFINED;
break;
}
case DUK_TAG_NULL: {
/* Note: not a typo, "object" is returned for a null value */
idx = DUK_STRIDX_LC_OBJECT;
break;
}
case DUK_TAG_BOOLEAN: {
idx = DUK_STRIDX_LC_BOOLEAN;
break;
}
case DUK_TAG_POINTER: {
/* implementation specific */
idx = DUK_STRIDX_LC_POINTER;
break;
}
case DUK_TAG_STRING: {
idx = DUK_STRIDX_LC_STRING;
break;
}
case DUK_TAG_OBJECT: {
duk_hobject *obj = DUK_TVAL_GET_OBJECT(tv_x);
DUK_ASSERT(obj != NULL);
if (DUK_HOBJECT_IS_CALLABLE(obj)) {
idx = DUK_STRIDX_LC_FUNCTION;
} else {
idx = DUK_STRIDX_LC_OBJECT;
}
break;
}
case DUK_TAG_BUFFER: {
/* implementation specific */
idx = DUK_STRIDX_LC_BUFFER;
break;
}
default: {
/* number */
DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_x));
idx = DUK_STRIDX_LC_NUMBER;
break;
}
}
DUK_ASSERT(idx >= 0 && idx < DUK_HEAP_NUM_STRINGS);
return thr->strs[idx];
}
/* Object.defineProperty() equivalent C binding. */
DUK_EXTERNAL void duk_def_prop(duk_context *ctx, duk_idx_t obj_index, duk_uint_t flags) {
duk_hthread *thr = (duk_hthread *) ctx;
duk_idx_t idx_base;
duk_hobject *obj;
duk_hstring *key;
duk_idx_t idx_value;
duk_hobject *get;
duk_hobject *set;
duk_uint_t is_data_desc;
duk_uint_t is_acc_desc;
DUK_ASSERT_CTX_VALID(ctx);
obj = duk_require_hobject(ctx, obj_index);
is_data_desc = flags & (DUK_DEFPROP_HAVE_VALUE | DUK_DEFPROP_HAVE_WRITABLE);
is_acc_desc = flags & (DUK_DEFPROP_HAVE_GETTER | DUK_DEFPROP_HAVE_SETTER);
if (is_data_desc && is_acc_desc) {
/* "Have" flags must not be conflicting so that they would
* apply to both a plain property and an accessor at the same
* time.
*/
goto fail_invalid_desc;
}
idx_base = duk_get_top_index(ctx);
if (flags & DUK_DEFPROP_HAVE_SETTER) {
duk_require_type_mask(ctx, idx_base, DUK_TYPE_MASK_UNDEFINED |
DUK_TYPE_MASK_OBJECT |
DUK_TYPE_MASK_LIGHTFUNC);
set = duk_get_hobject_or_lfunc_coerce(ctx, idx_base);
if (set != NULL && !DUK_HOBJECT_IS_CALLABLE(set)) {
goto fail_not_callable;
}
idx_base--;
} else {
set = NULL;
}
if (flags & DUK_DEFPROP_HAVE_GETTER) {
duk_require_type_mask(ctx, idx_base, DUK_TYPE_MASK_UNDEFINED |
DUK_TYPE_MASK_OBJECT |
DUK_TYPE_MASK_LIGHTFUNC);
get = duk_get_hobject_or_lfunc_coerce(ctx, idx_base);
if (get != NULL && !DUK_HOBJECT_IS_CALLABLE(get)) {
goto fail_not_callable;
}
idx_base--;
} else {
get = NULL;
}
if (flags & DUK_DEFPROP_HAVE_VALUE) {
idx_value = idx_base;
idx_base--;
} else {
idx_value = (duk_idx_t) -1;
}
key = duk_require_hstring(ctx, idx_base);
duk_require_valid_index(ctx, idx_base);
duk_hobject_define_property_helper(ctx,
flags /*defprop_flags*/,
obj,
key,
idx_value,
get,
set);
/* Clean up stack */
duk_set_top(ctx, idx_base);
/* [ ... obj ... ] */
return;
fail_invalid_desc:
DUK_ERROR(thr, DUK_ERR_TYPE_ERROR, DUK_STR_INVALID_DESCRIPTOR);
return;
fail_not_callable:
DUK_ERROR(thr, DUK_ERR_TYPE_ERROR, DUK_STR_NOT_CALLABLE);
return;
}
DUK_EXTERNAL void duk_new(duk_context *ctx, duk_idx_t nargs) {
/*
* There are two [[Construct]] operations in the specification:
*
* - E5 Section 13.2.2: for Function objects
* - E5 Section 15.3.4.5.2: for "bound" Function objects
*
* The chain of bound functions is resolved in Section 15.3.4.5.2,
* with arguments "piling up" until the [[Construct]] internal
* method is called on the final, actual Function object. Note
* that the "prototype" property is looked up *only* from the
* final object, *before* calling the constructor.
*
* Currently we follow the bound function chain here to get the
* "prototype" property value from the final, non-bound function.
* However, we let duk_handle_call() handle the argument "piling"
* when the constructor is called. The bound function chain is
* thus now processed twice.
*
* When constructing new Array instances, an unnecessary object is
* created and discarded now: the standard [[Construct]] creates an
* object, and calls the Array constructor. The Array constructor
* returns an Array instance, which is used as the result value for
* the "new" operation; the object created before the Array constructor
* call is discarded.
*
* This would be easy to fix, e.g. by knowing that the Array constructor
* will always create a replacement object and skip creating the fallback
* object in that case.
*
* Note: functions called via "new" need to know they are called as a
* constructor. For instance, built-in constructors behave differently
* depending on how they are called.
*/
/* XXX: merge this with duk_js_call.c, as this function implements
* core semantics (or perhaps merge the two files altogether).
*/
duk_hthread *thr = (duk_hthread *) ctx;
duk_hobject *proto;
duk_hobject *cons;
duk_hobject *fallback;
duk_idx_t idx_cons;
duk_small_uint_t call_flags;
DUK_ASSERT_CTX_VALID(ctx);
/* [... constructor arg1 ... argN] */
idx_cons = duk_require_normalize_index(ctx, -nargs - 1);
DUK_DDD(DUK_DDDPRINT("top=%ld, nargs=%ld, idx_cons=%ld",
(long) duk_get_top(ctx), (long) nargs, (long) idx_cons));
/* XXX: code duplication */
/*
* Figure out the final, non-bound constructor, to get "prototype"
* property.
*/
duk_dup(ctx, idx_cons);
for (;;) {
duk_tval *tv;
tv = DUK_GET_TVAL_NEGIDX(ctx, -1);
DUK_ASSERT(tv != NULL);
if (DUK_TVAL_IS_OBJECT(tv)) {
cons = DUK_TVAL_GET_OBJECT(tv);
DUK_ASSERT(cons != NULL);
if (!DUK_HOBJECT_IS_CALLABLE(cons) || !DUK_HOBJECT_HAS_CONSTRUCTABLE(cons)) {
/* Checking callability of the immediate target
* is important, same for constructability.
* Checking it for functions down the bound
* function chain is not strictly necessary
* because .bind() should normally reject them.
* But it's good to check anyway because it's
* technically possible to edit the bound function
* chain via internal keys.
*/
goto not_constructable;
}
if (!DUK_HOBJECT_HAS_BOUNDFUNC(cons)) {
break;
}
} else if (DUK_TVAL_IS_LIGHTFUNC(tv)) {
/* Lightfuncs cannot be bound. */
break;
} else {
/* Anything else is not constructable. */
goto not_constructable;
}
duk_get_prop_stridx_short(ctx, -1, DUK_STRIDX_INT_TARGET); /* -> [... cons target] */
duk_remove_m2(ctx); /* -> [... target] */
}
DUK_ASSERT(duk_is_callable(ctx, -1));
DUK_ASSERT(duk_is_lightfunc(ctx, -1) ||
(duk_get_hobject(ctx, -1) != NULL && !DUK_HOBJECT_HAS_BOUNDFUNC(duk_get_hobject(ctx, -1))));
/* [... constructor arg1 ... argN final_cons] */
/*
* Create "fallback" object to be used as the object instance,
* unless the constructor returns a replacement value.
* Its internal prototype needs to be set based on "prototype"
* property of the constructor.
*/
duk_push_object(ctx); /* class Object, extensible */
/* [... constructor arg1 ... argN final_cons fallback] */
duk_get_prop_stridx_short(ctx, -2, DUK_STRIDX_PROTOTYPE);
proto = duk_get_hobject(ctx, -1);
if (!proto) {
DUK_DDD(DUK_DDDPRINT("constructor has no 'prototype' property, or value not an object "
"-> leave standard Object prototype as fallback prototype"));
} else {
DUK_DDD(DUK_DDDPRINT("constructor has 'prototype' property with object value "
"-> set fallback prototype to that value: %!iO", (duk_heaphdr *) proto));
fallback = duk_get_hobject(ctx, -2);
DUK_ASSERT(fallback != NULL);
DUK_HOBJECT_SET_PROTOTYPE_UPDREF(thr, fallback, proto);
}
duk_pop(ctx);
/* [... constructor arg1 ... argN final_cons fallback] */
/*
* Manipulate callstack for the call.
*/
duk_dup_top(ctx);
duk_insert(ctx, idx_cons + 1); /* use fallback as 'this' value */
duk_insert(ctx, idx_cons); /* also stash it before constructor,
* in case we need it (as the fallback value)
*/
duk_pop(ctx); /* pop final_cons */
/* [... fallback constructor fallback(this) arg1 ... argN];
* Note: idx_cons points to first 'fallback', not 'constructor'.
*/
DUK_DDD(DUK_DDDPRINT("before call, idx_cons+1 (constructor) -> %!T, idx_cons+2 (fallback/this) -> %!T, "
"nargs=%ld, top=%ld",
(duk_tval *) duk_get_tval(ctx, idx_cons + 1),
(duk_tval *) duk_get_tval(ctx, idx_cons + 2),
(long) nargs,
(long) duk_get_top(ctx)));
/*
* Call the constructor function (called in "constructor mode").
*/
call_flags = DUK_CALL_FLAG_CONSTRUCTOR_CALL; /* not protected, respect reclimit, is a constructor call */
duk_handle_call_unprotected(thr, /* thread */
nargs, /* num_stack_args */
call_flags); /* call_flags */
/* [... fallback retval] */
DUK_DDD(DUK_DDDPRINT("constructor call finished, fallback=%!iT, retval=%!iT",
(duk_tval *) duk_get_tval(ctx, -2),
(duk_tval *) duk_get_tval(ctx, -1)));
/*
* Determine whether to use the constructor return value as the created
* object instance or not.
*/
if (duk_check_type_mask(ctx, -1, DUK_TYPE_MASK_OBJECT |
DUK_TYPE_MASK_BUFFER |
DUK_TYPE_MASK_LIGHTFUNC)) {
duk_remove_m2(ctx);
} else {
duk_pop(ctx);
}
/*
* Augment created errors upon creation (not when they are thrown or
* rethrown). __FILE__ and __LINE__ are not desirable here; the call
* stack reflects the caller which is correct.
*/
#if defined(DUK_USE_AUGMENT_ERROR_CREATE)
duk_hthread_sync_currpc(thr);
duk_err_augment_error_create(thr, thr, NULL, 0, 1 /*noblame_fileline*/);
#endif
/* [... retval] */
return;
not_constructable:
#if defined(DUK_USE_VERBOSE_ERRORS)
#if defined(DUK_USE_PARANOID_ERRORS)
DUK_ERROR_FMT1(thr, DUK_ERR_TYPE_ERROR, "%s not constructable", duk_get_type_name(ctx, -1));
#else
DUK_ERROR_FMT1(thr, DUK_ERR_TYPE_ERROR, "%s not constructable", duk_push_string_readable(ctx, -1));
#endif
#else
DUK_ERROR_TYPE(thr, "not constructable");
#endif
}
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(thr, DUK_ERR_TYPE_ERROR, "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(thr, DUK_ERR_INTERNAL_ERROR, 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 ] */
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.
*/
val = DUK_HOBJECT_GET_PROTOTYPE(thr->heap, val);
if (!val) {
goto pop_and_false;
} else if (val == proto) {
goto pop_and_true;
}
/* follow prototype chain */
} while (--sanity > 0);
if (sanity == 0) {
DUK_ERROR(thr, DUK_ERR_INTERNAL_ERROR, 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;
}