godot/platform/javascript/javascript_eval.cpp

/*************************************************************************/
/*  javascript_eval.cpp                                                  */
/*************************************************************************/
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#ifdef JAVASCRIPT_EVAL_ENABLED

#include "api/javascript_eval.h"
#include "emscripten.h"

extern "C" {
union js_eval_ret {
	uint32_t b;
	double d;
	char *s;
};

extern int godot_js_eval(const char *p_js, int p_use_global_ctx, union js_eval_ret *p_union_ptr, void *p_byte_arr, void *p_byte_arr_write, void *(*p_callback)(void *p_ptr, void *p_ptr2, int p_len));
}

void *resize_PackedByteArray_and_open_write(void *p_arr, void *r_write, int p_len) {
	PackedByteArray *arr = (PackedByteArray *)p_arr;
	VectorWriteProxy<uint8_t> *write = (VectorWriteProxy<uint8_t> *)r_write;
	arr->resize(p_len);
	*write = arr->write;
	return arr->ptrw();
}

Variant JavaScript::eval(const String &p_code, bool p_use_global_exec_context) {
	union js_eval_ret js_data;
	PackedByteArray arr;
	VectorWriteProxy<uint8_t> arr_write;

	Variant::Type return_type = static_cast<Variant::Type>(godot_js_eval(p_code.utf8().get_data(), p_use_global_exec_context, &js_data, &arr, &arr_write, resize_PackedByteArray_and_open_write));

	switch (return_type) {
		case Variant::BOOL:
			return js_data.b;
		case Variant::FLOAT:
			return js_data.d;
		case Variant::STRING: {
			String str = String::utf8(js_data.s);
			free(js_data.s); // Must free the string allocated in JS.
			return str;
		}
		case Variant::PACKED_BYTE_ARRAY:
			arr_write = VectorWriteProxy<uint8_t>();
			return arr;
		default:
			return Variant();
	}
}

#endif // JAVASCRIPT_EVAL_ENABLED