C++ DUK_ASSERT_TOP函数代码示例

int duk_builtin_number_prototype_to_exponential(duk_context *ctx) {
	int frac_undefined;
	int frac_digits;
	double d;
	int c;
	int n2s_flags;

	d = push_this_number_plain(ctx);

	frac_undefined = duk_is_undefined(ctx, 0);
	duk_to_int(ctx, 0);  /* for side effects */

	c = DUK_FPCLASSIFY(d);
	if (c == DUK_FP_NAN || c == DUK_FP_INFINITE) {
		goto use_to_string;
	}

	frac_digits = duk_to_int_check_range(ctx, 0, 0, 20);

	n2s_flags = DUK_N2S_FLAG_FORCE_EXP |
	           (frac_undefined ? 0 : DUK_N2S_FLAG_FIXED_FORMAT);

	duk_numconv_stringify(ctx,
	                      10 /*radix*/,
	                      frac_digits + 1 /*leading digit + fractions*/,
	                      n2s_flags /*flags*/);
	return 1;

 use_to_string:
	DUK_ASSERT_TOP(ctx, 2);
	duk_to_string(ctx, -1);
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_object_constructor_create(duk_hthread *thr) {
	duk_hobject *proto;

	DUK_ASSERT_TOP(thr, 2);

#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
	duk_hbufobj_promote_plain(thr, 0);
#endif
	proto = duk_require_hobject_accept_mask(thr, 0, DUK_TYPE_MASK_NULL);
	DUK_ASSERT(proto != NULL || duk_is_null(thr, 0));

	(void) duk_push_object_helper_proto(thr,
	                                    DUK_HOBJECT_FLAG_EXTENSIBLE |
	                                    DUK_HOBJECT_FLAG_FASTREFS |
	                                    DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJECT),
	                                    proto);

	if (!duk_is_undefined(thr, 1)) {
		/* [ O Properties obj ] */

		duk_replace(thr, 0);

		/* [ obj Properties ] */

		/* Just call the "original" Object.defineProperties() to
		 * finish up.
		 */

		return duk_bi_object_constructor_define_properties(thr);
	}

	/* [ O Properties obj ] */

	return 1;
}

duk_ret_t duk_bi_number_prototype_to_fixed(duk_context *ctx) {
	duk_small_int_t frac_digits;
	duk_double_t d;
	duk_small_int_t c;
	duk_small_uint_t n2s_flags;

	frac_digits = (duk_small_int_t) duk_to_int_check_range(ctx, 0, 0, 20);
	d = duk__push_this_number_plain(ctx);

	c = (duk_small_int_t) DUK_FPCLASSIFY(d);
	if (c == DUK_FP_NAN || c == DUK_FP_INFINITE) {
		goto use_to_string;
	}

	if (d >= 1.0e21 || d <= -1.0e21) {
		goto use_to_string;
	}

	n2s_flags = DUK_N2S_FLAG_FIXED_FORMAT |
	            DUK_N2S_FLAG_FRACTION_DIGITS;

	duk_numconv_stringify(ctx,
	                      10 /*radix*/,
	                      frac_digits /*digits*/,
	                      n2s_flags /*flags*/);
	return 1;

 use_to_string:
	DUK_ASSERT_TOP(ctx, 2);
	duk_to_string(ctx, -1);
	return 1;
}

DUK_LOCAL duk_ret_t duk__error_setter_helper(duk_context *ctx, duk_small_uint_t stridx_key) {
	/* Attempt to write 'stack', 'fileName', 'lineNumber' works as if
	 * user code called Object.defineProperty() to create an overriding
	 * own property.  This allows user code to overwrite .fileName etc
	 * intuitively as e.g. "err.fileName = 'dummy'" as one might expect.
	 * See https://github.com/svaarala/duktape/issues/387.
	 */

	DUK_ASSERT_TOP(ctx, 1);  /* fixed arg count: value */

	duk_push_this(ctx);
	duk_push_hstring_stridx(ctx, (duk_small_int_t) stridx_key);
	duk_dup_0(ctx);

	/* [ ... obj key value ] */

	DUK_DD(DUK_DDPRINT("error setter: %!T %!T %!T",
	                   duk_get_tval(ctx, -3), duk_get_tval(ctx, -2), duk_get_tval(ctx, -1)));

	duk_def_prop(ctx, -3, DUK_DEFPROP_HAVE_VALUE |
	                      DUK_DEFPROP_HAVE_WRITABLE | DUK_DEFPROP_WRITABLE |
	                      DUK_DEFPROP_HAVE_ENUMERABLE | /*not enumerable*/
	                      DUK_DEFPROP_HAVE_CONFIGURABLE | DUK_DEFPROP_CONFIGURABLE);
	return 0;
}

int duk_bi_error_prototype_nop_setter(duk_context *ctx) {
	/* Attempt to write 'stack', 'fileName', 'lineNumber' is a silent no-op.
	 * User can use Object.defineProperty() to override this behavior.
	 */
	DUK_ASSERT_TOP(ctx, 1);  /* fixed arg count */
	DUK_UNREF(ctx);
	return 0;
}

DUK_INTERNAL duk_ret_t duk_bi_array_prototype_reverse(duk_context *ctx) {
	duk_uint32_t len;
	duk_uint32_t middle;
	duk_uint32_t lower, upper;
	duk_bool_t have_lower, have_upper;

	len = duk__push_this_obj_len_u32(ctx);
	middle = len / 2;

	/* If len <= 1, middle will be 0 and for-loop bails out
	 * immediately (0 < 0 -> false).
	 */

	for (lower = 0; lower < middle; lower++) {
		DUK_ASSERT(len >= 2);
		DUK_ASSERT_TOP(ctx, 2);

		DUK_ASSERT(len >= lower + 1);
		upper = len - lower - 1;

		have_lower = duk_get_prop_index(ctx, -2, (duk_uarridx_t) lower);
		have_upper = duk_get_prop_index(ctx, -3, (duk_uarridx_t) upper);

		/* [ ToObject(this) ToUint32(length) lowerValue upperValue ] */

		if (have_upper) {
			duk_put_prop_index(ctx, -4, (duk_uarridx_t) lower);
		} else {
			duk_del_prop_index(ctx, -4, (duk_uarridx_t) lower);
			duk_pop(ctx);
		}

		if (have_lower) {
			duk_put_prop_index(ctx, -3, (duk_uarridx_t) upper);
		} else {
			duk_del_prop_index(ctx, -3, (duk_uarridx_t) upper);
			duk_pop(ctx);
		}

		DUK_ASSERT_TOP(ctx, 2);
	}

	DUK_ASSERT_TOP(ctx, 2);
	duk_pop(ctx);  /* -> [ ToObject(this) ] */
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_duktape_object_enc(duk_context *ctx) {
	duk_hthread *thr = (duk_hthread *) ctx;
	duk_hstring *h_str;

	DUK_UNREF(thr);

	/* Vararg function: must be careful to check/require arguments.
	 * The JSON helpers accept invalid indices and treat them like
	 * non-existent optional parameters.
	 */

	h_str = duk_require_hstring(ctx, 0);
	duk_require_valid_index(ctx, 1);

	if (h_str == DUK_HTHREAD_STRING_HEX(thr)) {
		duk_set_top(ctx, 2);
		duk_hex_encode(ctx, 1);
		DUK_ASSERT_TOP(ctx, 2);
	} else if (h_str == DUK_HTHREAD_STRING_BASE64(thr)) {
		duk_set_top(ctx, 2);
		duk_base64_encode(ctx, 1);
		DUK_ASSERT_TOP(ctx, 2);
#ifdef DUK_USE_JX
	} else if (h_str == DUK_HTHREAD_STRING_JX(thr)) {
		duk_bi_json_stringify_helper(ctx,
		                             1 /*idx_value*/,
		                             2 /*idx_replacer*/,
		                             3 /*idx_space*/,
		                             DUK_JSON_FLAG_EXT_CUSTOM |
		                             DUK_JSON_FLAG_ASCII_ONLY |
		                             DUK_JSON_FLAG_AVOID_KEY_QUOTES /*flags*/);
#endif
#ifdef DUK_USE_JC
	} else if (h_str == DUK_HTHREAD_STRING_JC(thr)) {
		duk_bi_json_stringify_helper(ctx,
		                             1 /*idx_value*/,
		                             2 /*idx_replacer*/,
		                             3 /*idx_space*/,
		                             DUK_JSON_FLAG_EXT_COMPATIBLE |
		                             DUK_JSON_FLAG_ASCII_ONLY /*flags*/);
#endif
	} else {
		return DUK_RET_TYPE_ERROR;
	}
	return 1;
}

duk_ret_t duk_bi_number_prototype_to_precision(duk_context *ctx) {
	/* The specification has quite awkward order of coercion and
	 * checks for toPrecision().  The operations below are a bit
	 * reordered, within constraints of observable side effects.
	 */

	duk_double_t d;
	duk_small_int_t prec;
	duk_small_int_t c;
	duk_small_uint_t n2s_flags;

	DUK_ASSERT_TOP(ctx, 1);

	d = duk__push_this_number_plain(ctx);
	if (duk_is_undefined(ctx, 0)) {
		goto use_to_string;
	}
	DUK_ASSERT_TOP(ctx, 2);

	duk_to_int(ctx, 0);  /* for side effects */

	c = (duk_small_int_t) DUK_FPCLASSIFY(d);
	if (c == DUK_FP_NAN || c == DUK_FP_INFINITE) {
		goto use_to_string;
	}

	prec = (duk_small_int_t) duk_to_int_check_range(ctx, 0, 1, 21);

	n2s_flags = DUK_N2S_FLAG_FIXED_FORMAT |
	            DUK_N2S_FLAG_NO_ZERO_PAD;

	duk_numconv_stringify(ctx,
	                      10 /*radix*/,
	                      prec /*digits*/,
	                      n2s_flags /*flags*/);
	return 1;

 use_to_string:
	/* Used when precision is undefined; also used for NaN (-> "NaN"),
	 * and +/- infinity (-> "Infinity", "-Infinity").
	 */

	DUK_ASSERT_TOP(ctx, 2);
	duk_to_string(ctx, -1);
	return 1;
}

int duk_builtin_duk_object_dec(duk_context *ctx) {
	duk_hthread *thr = (duk_hthread *) ctx;
	duk_hstring *h_str;

	h_str = duk_to_hstring(ctx, 0);
	if (h_str == DUK_HTHREAD_STRING_HEX(thr)) {
		duk_hex_decode(ctx, 1);
		DUK_ASSERT_TOP(ctx, 2);
		return 1;
	} else if (h_str == DUK_HTHREAD_STRING_BASE64(thr)) {
		duk_base64_decode(ctx, 1);
		DUK_ASSERT_TOP(ctx, 2);
		return 1;
	} else {
		return DUK_RET_TYPE_ERROR;
	}
}

void duk_hobject_run_finalizer(duk_hthread *thr, duk_hobject *obj) {
	duk_context *ctx = (duk_context *) thr;
	int rc;
#ifdef DUK_USE_ASSERTIONS
	int entry_top;
#endif

	DUK_DDDPRINT("running object finalizer for object: %p", (void *) obj);

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(ctx != NULL);
	DUK_ASSERT(obj != NULL);

	/* FIXME: assert stack space */

#ifdef DUK_USE_ASSERTIONS
	entry_top = duk_get_top(ctx);
#endif
	/*
	 *  Get and call the finalizer.  All of this must be wrapped
	 *  in a protected call, because even getting the finalizer
	 *  may trigger an error (getter may throw one, for instance).
	 */

	/* FIXME: use a NULL error handler for the finalizer call? */

	DUK_DDDPRINT("-> finalizer found, calling wrapped finalize helper");
	duk_push_hobject(ctx, obj);  /* this also increases refcount by one */
	rc = duk_safe_call(ctx, _finalize_helper, 0 /*nargs*/, 1 /*nrets*/, DUK_INVALID_INDEX);  /* -> [... obj retval/error] */
	DUK_ASSERT_TOP(ctx, entry_top + 2);  /* duk_safe_call discipline */

	if (rc != DUK_ERR_EXEC_SUCCESS) {
		/* Note: we ask for one return value from duk_safe_call to get this
		 * error debugging here.
		 */
		DUK_DPRINT("wrapped finalizer call failed for object %p (ignored); error: %!T",
		           (void *) obj, duk_get_tval(ctx, -1));
	}
	duk_pop_2(ctx);  /* -> [...] */

	DUK_ASSERT_TOP(ctx, entry_top);
}

DUK_INTERNAL duk_ret_t duk_bi_regexp_prototype_tostring(duk_hthread *thr) {
	/* This must be generic in ES2015 and later. */
	DUK_ASSERT_TOP(thr, 0);
	duk_push_this(thr);
	duk_push_literal(thr, "/");
	duk_get_prop_stridx(thr, 0, DUK_STRIDX_SOURCE);
	duk_dup_m2(thr);  /* another "/" */
	duk_get_prop_stridx(thr, 0, DUK_STRIDX_FLAGS);
	duk_concat(thr, 4);
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_object_constructor_seal_freeze_shared(duk_context *ctx) {
	duk_hthread *thr = (duk_hthread *) ctx;
	duk_hobject *h;
	duk_bool_t is_freeze;

	DUK_ASSERT_TOP(ctx, 1);

	is_freeze = (duk_bool_t) duk_get_current_magic(ctx);
	if (duk_is_buffer(ctx, 0)) {
		/* Plain buffer: already sealed, but not frozen (and can't be frozen
		 * because index properties can't be made non-writable.
		 */
		if (is_freeze) {
			goto fail_cannot_freeze;
		}
		return 1;
	} else if (duk_is_lightfunc(ctx, 0)) {
		/* Lightfunc: already sealed and frozen, success. */
		return 1;
	}
#if 0
	/* Seal/freeze are quite rare in practice so it'd be nice to get the
	 * correct behavior simply via automatic promotion (at the cost of some
	 * memory churn).  However, the promoted objects don't behave the same,
	 * e.g. promoted lightfuncs are extensible.
	 */
	h = duk_require_hobject_promote_mask(ctx, 0, DUK_TYPE_MASK_LIGHTFUNC | DUK_TYPE_MASK_BUFFER);
#endif

	h = duk_get_hobject(ctx, 0);
	if (h == NULL) {
		/* ES2015 Sections 19.1.2.5, 19.1.2.17 */
		return 1;
	}

	if (is_freeze && DUK_HOBJECT_IS_BUFOBJ(h)) {
		/* Buffer objects cannot be frozen because there's no internal
		 * support for making virtual array indices non-writable.
		 */
		DUK_DD(DUK_DDPRINT("cannot freeze a buffer object"));
		goto fail_cannot_freeze;
	}

	duk_hobject_object_seal_freeze_helper(thr, h, is_freeze);

	/* Sealed and frozen objects cannot gain any more properties,
	 * so this is a good time to compact them.
	 */
	duk_hobject_compact_props(thr, h);
	return 1;

 fail_cannot_freeze:
	DUK_DCERROR_TYPE_INVALID_ARGS(thr);  /* XXX: proper error message */
}

DUK_INTERNAL duk_ret_t duk_bi_object_prototype_to_locale_string(duk_context *ctx) {
	DUK_ASSERT_TOP(ctx, 0);
	(void) duk_push_this_coercible_to_object(ctx);
	duk_get_prop_stridx(ctx, 0, DUK_STRIDX_TO_STRING);
	if (!duk_is_callable(ctx, 1)) {
		return DUK_RET_TYPE_ERROR;
	}
	duk_dup(ctx, 0);  /* -> [ O toString O ] */
	duk_call_method(ctx, 0);  /* XXX: call method tailcall? */
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_object_prototype_to_locale_string(duk_hthread *thr) {
	DUK_ASSERT_TOP(thr, 0);
	(void) duk_push_this_coercible_to_object(thr);
	duk_get_prop_stridx_short(thr, 0, DUK_STRIDX_TO_STRING);
#if 0  /* This is mentioned explicitly in the E5.1 spec, but duk_call_method() checks for it in practice. */
	duk_require_callable(thr, 1);
#endif
	duk_dup_0(thr);  /* -> [ O toString O ] */
	duk_call_method(thr, 0);  /* XXX: call method tail call? */
	return 1;
}

DUK_INTERNAL duk_ret_t duk_bi_proxy_constructor(duk_context *ctx) {
	duk_hobject *h_target;
	duk_hobject *h_handler;

	if (!duk_is_constructor_call(ctx)) {
		return DUK_RET_TYPE_ERROR;
	}

	/* Reject a proxy object as the target because it would need
	 * special handler in property lookups.  (ES6 has no such restriction)
	 */
	h_target = duk_require_hobject_or_lfunc_coerce(ctx, 0);
	DUK_ASSERT(h_target != NULL);
	if (DUK_HOBJECT_HAS_EXOTIC_PROXYOBJ(h_target)) {
		return DUK_RET_TYPE_ERROR;
	}

	/* Reject a proxy object as the handler because it would cause
	 * potentially unbounded recursion.  (ES6 has no such restriction)
	 */
	h_handler = duk_require_hobject_or_lfunc_coerce(ctx, 1);
	DUK_ASSERT(h_handler != NULL);
	if (DUK_HOBJECT_HAS_EXOTIC_PROXYOBJ(h_handler)) {
		return DUK_RET_TYPE_ERROR;
	}

	/* XXX: the returned value is exotic in ES6, but we use a
	 * simple object here with no prototype.  Without a prototype,
	 * [[DefaultValue]] coercion fails which is abit confusing.
	 * No callable check/handling in the current Proxy subset.
	 */
	(void) duk_push_object_helper_proto(ctx,
	                                    DUK_HOBJECT_FLAG_EXTENSIBLE |
	                                    DUK_HOBJECT_FLAG_EXOTIC_PROXYOBJ |
	                                    DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJECT),
	                                    NULL);
	DUK_ASSERT_TOP(ctx, 3);

	/* Make _Target and _Handler non-configurable and non-writable.
	 * They can still be forcibly changed by C code (both user and
	 * Duktape internal), but not by Ecmascript code.
	 */

	/* Proxy target */
	duk_dup(ctx, 0);
	duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_INT_TARGET, DUK_PROPDESC_FLAGS_NONE);

	/* Proxy handler */
	duk_dup(ctx, 1);
	duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_INT_HANDLER, DUK_PROPDESC_FLAGS_NONE);

	return 1;  /* replacement handler */
}