subconverter/include/quickjspp.hpp
2023-11-15 22:49:38 +08:00

2233 lines
72 KiB
C++

#pragma once
#include "quickjs/quickjs.h"
#include <vector>
#include <string_view>
#include <string>
#include <cassert>
#include <memory>
#include <cstddef>
#include <algorithm>
#include <tuple>
#include <functional>
#include <stdexcept>
#include <variant>
#include <optional>
#include <type_traits>
#include <unordered_map>
#include <fstream>
#include <ios>
#include <sstream>
#include <filesystem>
#if defined(__cpp_rtti)
#define QJSPP_TYPENAME(...) (typeid(__VA_ARGS__).name())
#else
#define QJSPP_TYPENAME(...) #__VA_ARGS__
#endif
namespace qjs {
class Context;
class Value;
/** Exception type.
* Indicates that exception has occured in JS context.
*/
class exception {
JSContext * ctx;
public:
exception(JSContext * ctx) : ctx(ctx) {}
Context & context() const;
/// Clears and returns the occurred exception.
Value get();
};
/** std::shared_ptr, for compatibility with quickjspp v2. */
template <class T> using shared_ptr = std::shared_ptr<T>;
/** std::make_shared, for compatibility with quickjspp v2. */
template <class T, typename... Args>
shared_ptr<T> make_shared(JSContext *, Args&&... args)
{
return std::make_shared<T>(std::forward<Args>(args)...);
}
/** Javascript conversion traits.
* Describes how to convert type R to/from JSValue. Second template argument can be used for SFINAE/enable_if type filters.
*/
template <typename R, typename /*_SFINAE*/ = void>
struct js_traits
{
/** Create an object of C++ type R given JSValue v and JSContext.
* This function is intentionally not implemented. User should implement this function for their own type.
* @param v This value is passed as JSValueConst so it should be freed by the caller.
* @throws exception in case of conversion error
*/
static R unwrap(JSContext * ctx, JSValueConst v) = delete;
/** Create JSValue from an object of type R and JSContext.
* This function is intentionally not implemented. User should implement this function for their own type.
* @return Returns JSValue which should be freed by the caller or JS_EXCEPTION in case of error.
*/
static JSValue wrap(JSContext * ctx, R value) = delete;
};
/** Conversion traits for JSValue (identity).
*/
template <>
struct js_traits<JSValue>
{
static JSValue unwrap(JSContext * ctx, JSValueConst v) noexcept
{
return JS_DupValue(ctx, v);
}
static JSValue wrap(JSContext * ctx, JSValue&& v) noexcept
{
return v;
}
};
/** Conversion traits for integers.
* Intentionally doesn't define traits for uint64_t since it can be typedefed to JSValue. (@see JS_NAN_BOXING)
*/
template <typename Int>
struct js_traits<Int, std::enable_if_t<std::is_integral_v<Int> && sizeof(Int) <= sizeof(int64_t) && !std::is_same_v<Int, uint64_t>>>
{
/// @throws exception
static Int unwrap(JSContext * ctx, JSValueConst v)
{
if constexpr (sizeof(Int) > sizeof(int32_t))
{
int64_t r;
if(JS_ToInt64(ctx, &r, v))
throw exception{ctx};
return static_cast<Int>(r);
}
else
{
int32_t r;
if(JS_ToInt32(ctx, &r, v))
throw exception{ctx};
return static_cast<Int>(r);
}
}
static JSValue wrap(JSContext * ctx, Int i) noexcept
{
if constexpr (std::is_same_v<Int, uint32_t> || sizeof(Int) > sizeof(int32_t))
return JS_NewInt64(ctx, static_cast<Int>(i));
else
return JS_NewInt32(ctx, static_cast<Int>(i));
}
};
/** Conversion traits for boolean.
*/
template <>
struct js_traits<bool>
{
static bool unwrap(JSContext * ctx, JSValueConst v) noexcept
{
// TODO: is this behaviour correct?
return JS_ToBool(ctx, v) > 0;
}
static JSValue wrap(JSContext * ctx, bool i) noexcept
{
return JS_NewBool(ctx, i);
}
};
/** Conversion trait for void.
*/
template <>
struct js_traits<void>
{
/// @throws exception if jsvalue is neither undefined nor null
static void unwrap(JSContext * ctx, JSValueConst value)
{
if(JS_IsException(value))
throw exception{ctx};
}
};
/** Conversion traits for float64/double.
*/
template <>
struct js_traits<double>
{
/// @throws exception
static double unwrap(JSContext * ctx, JSValueConst v)
{
double r;
if(JS_ToFloat64(ctx, &r, v))
throw exception{ctx};
return r;
}
static JSValue wrap(JSContext * ctx, double i) noexcept
{
return JS_NewFloat64(ctx, i);
}
};
namespace detail {
/** Fake std::string_view which frees the string on destruction.
*/
class js_string : public std::string_view
{
using Base = std::string_view;
JSContext * ctx = nullptr;
friend struct js_traits<std::string_view>;
js_string(JSContext * ctx, const char * ptr, std::size_t len) : Base(ptr, len), ctx(ctx) {}
public:
template <typename... Args>
js_string(Args&& ... args) : Base(std::forward<Args>(args)...), ctx(nullptr) {}
js_string(const js_string& other) = delete;
operator const char *() const
{
return this->data();
}
~js_string()
{
if(ctx)
JS_FreeCString(ctx, this->data());
}
};
} // namespace detail
/** Conversion traits from std::string_view and to detail::js_string. */
template <>
struct js_traits<std::string_view>
{
static detail::js_string unwrap(JSContext * ctx, JSValueConst v)
{
size_t plen;
const char * ptr = JS_ToCStringLen(ctx, &plen, v);
if(!ptr)
throw exception{ctx};
return detail::js_string{ctx, ptr, plen};
}
static JSValue wrap(JSContext * ctx, std::string_view str) noexcept
{
return JS_NewStringLen(ctx, str.data(), str.size());
}
};
/** Conversion traits for std::string */
template <> // slower
struct js_traits<std::string>
{
static std::string unwrap(JSContext * ctx, JSValueConst v)
{
auto str_view = js_traits<std::string_view>::unwrap(ctx, v);
return std::string{str_view.data(), str_view.size()};
}
static JSValue wrap(JSContext * ctx, const std::string& str) noexcept
{
return JS_NewStringLen(ctx, str.data(), str.size());
}
};
/** Conversion from const char * */
template <>
struct js_traits<const char *>
{
static JSValue wrap(JSContext * ctx, const char * str) noexcept
{
return JS_NewString(ctx, str);
}
static detail::js_string unwrap(JSContext * ctx, JSValueConst v)
{
return js_traits<std::string_view>::unwrap(ctx, v);
}
};
/** Conversion from const std::variant */
template <typename ... Ts>
struct js_traits<std::variant<Ts...>>
{
static JSValue wrap(JSContext * ctx, std::variant<Ts...> value) noexcept
{
return std::visit([ctx](auto&& value) {
using T = std::decay_t<decltype(value)>;
return js_traits<T>::wrap(ctx, value);
}, std::move(value));
}
/* Useful type traits */
template <typename T> struct is_shared_ptr : std::false_type {};
template <typename T> struct is_shared_ptr<std::shared_ptr<T>> : std::true_type {};
template <typename T> struct is_string
{
static constexpr bool value = std::is_same_v<T, const char *> || std::is_same_v<std::decay_t<T>, std::string> ||
std::is_same_v<std::decay_t<T>, std::string_view>;
};
template <typename T> struct is_boolean { static constexpr bool value = std::is_same_v<std::decay_t<T>, bool>; };
template <typename T> struct is_double { static constexpr bool value = std::is_same_v<std::decay_t<T>, double>; };
template <typename T> struct is_vector : std::false_type {};
template <typename T> struct is_vector<std::vector<T>> : std::true_type {};
template <typename T> struct is_pair : std::false_type {};
template <typename U, typename V> struct is_pair<std::pair<U, V>> : std::true_type {};
template <typename T> struct is_variant : std::false_type {};
template <typename ... Us> struct is_variant<std::variant<Us...>> : std::true_type {};
/** Attempt to match common types (integral, floating-point, string, etc.) */
template <template <typename R> typename Trait, typename U, typename ... Us>
static std::optional<std::variant<Ts...>> unwrapImpl(JSContext * ctx, JSValueConst v)
{
if constexpr (Trait<U>::value)
{
return js_traits<U>::unwrap(ctx, v);
}
if constexpr ((sizeof ... (Us)) > 0)
{
return unwrapImpl<Trait, Us...>(ctx, v);
}
return std::nullopt;
}
/** Attempt to match class ID with type */
template <typename U, typename ... Us>
static std::optional<std::variant<Ts...>> unwrapObj(JSContext * ctx, JSValueConst v, JSClassID class_id)
{
if constexpr (is_shared_ptr<U>::value)
{
if(class_id == js_traits<U>::QJSClassId)
{
return js_traits<U>::unwrap(ctx, v);
}
}
// try to unwrap embedded variant (variant<variant<...>>), might be slow
if constexpr (is_variant<U>::value)
{
if(auto opt = js_traits<std::optional<U>>::unwrap(ctx, v))
return *opt;
}
if constexpr (is_vector<U>::value)
{
if(JS_IsArray(ctx, v) == 1)
{
auto firstElement = JS_GetPropertyUint32(ctx, v, 0);
bool ok = isCompatible<std::decay_t<typename U::value_type>>(ctx, firstElement);
JS_FreeValue(ctx, firstElement);
if(ok)
{
return U{js_traits<U>::unwrap(ctx, v)};
}
}
}
if constexpr (is_pair<U>::value)
{
if(JS_IsArray(ctx, v) == 1)
{
// todo: check length?
auto firstElement = JS_GetPropertyUint32(ctx, v, 0);
auto secondElement = JS_GetPropertyUint32(ctx, v, 1);
bool ok = isCompatible<std::decay_t<typename U::first_type>>(ctx, firstElement)
&& isCompatible<std::decay_t<typename U::second_type>>(ctx, secondElement);
JS_FreeValue(ctx, firstElement);
JS_FreeValue(ctx, secondElement);
if(ok)
{
return U{js_traits<U>::unwrap(ctx, v)};
}
}
}
if constexpr ((sizeof ... (Us)) > 0)
{
return unwrapObj<Us...>(ctx, v, class_id);
}
return std::nullopt;
}
/** Attempt to cast to types satisfying traits, ordered in terms of priority */
template <template <typename T> typename Trait, template <typename T> typename ... Traits>
static std::variant<Ts...> unwrapPriority(JSContext * ctx, JSValueConst v)
{
if(auto result = unwrapImpl<Trait, Ts...>(ctx, v))
{
return *result;
}
if constexpr ((sizeof ... (Traits)) > 0)
{
return unwrapPriority<Traits...>(ctx, v);
}
JS_ThrowTypeError(ctx, "Expected type %s", QJSPP_TYPENAME(std::variant<Ts...>));
throw exception{ctx};
}
template <typename T>
static bool isCompatible(JSContext * ctx, JSValueConst v) noexcept
{
//const char * type_name = typeid(T).name();
switch(JS_VALUE_GET_TAG(v))
{
case JS_TAG_STRING:
return is_string<T>::value;
case JS_TAG_FUNCTION_BYTECODE:
return std::is_function<T>::value;
case JS_TAG_OBJECT:
if(JS_IsArray(ctx, v) == 1)
return is_vector<T>::value || is_pair<T>::value;
if constexpr (is_shared_ptr<T>::value)
{
if(JS_GetClassID(v) == js_traits<T>::QJSClassId)
return true;
}
return false;
case JS_TAG_INT:
[[fallthrough]];
case JS_TAG_BIG_INT:
return std::is_integral_v<T> || std::is_floating_point_v<T>;
case JS_TAG_BOOL:
return is_boolean<T>::value || std::is_integral_v<T> || std::is_floating_point_v<T>;
case JS_TAG_BIG_DECIMAL:
[[fallthrough]];
case JS_TAG_BIG_FLOAT:
[[fallthrough]];
case JS_TAG_FLOAT64:
default: // >JS_TAG_FLOAT64 (JS_NAN_BOXING)
return is_double<T>::value || std::is_floating_point_v<T>;
case JS_TAG_SYMBOL:
[[fallthrough]];
case JS_TAG_MODULE:
[[fallthrough]];
case JS_TAG_NULL:
[[fallthrough]];
case JS_TAG_UNDEFINED:
[[fallthrough]];
case JS_TAG_UNINITIALIZED:
[[fallthrough]];
case JS_TAG_CATCH_OFFSET:
[[fallthrough]];
case JS_TAG_EXCEPTION:
break;
}
return false;
}
static std::variant<Ts...> unwrap(JSContext * ctx, JSValueConst v)
{
const auto tag = JS_VALUE_GET_TAG(v);
switch(tag)
{
case JS_TAG_STRING:
return unwrapPriority<is_string>(ctx, v);
case JS_TAG_FUNCTION_BYTECODE:
return unwrapPriority<std::is_function>(ctx, v);
case JS_TAG_OBJECT:
if(auto result = unwrapObj<Ts...>(ctx, v, JS_GetClassID(v)))
{
return *result;
}
JS_ThrowTypeError(ctx, "Expected type %s, got object with classid %d",
QJSPP_TYPENAME(std::variant<Ts...>), JS_GetClassID(v));
break;
case JS_TAG_INT:
[[fallthrough]];
case JS_TAG_BIG_INT:
return unwrapPriority<std::is_integral, std::is_floating_point>(ctx, v);
case JS_TAG_BOOL:
return unwrapPriority<is_boolean, std::is_integral, std::is_floating_point>(ctx, v);
case JS_TAG_SYMBOL:
[[fallthrough]];
case JS_TAG_MODULE:
[[fallthrough]];
case JS_TAG_NULL:
[[fallthrough]];
case JS_TAG_UNDEFINED:
[[fallthrough]];
case JS_TAG_UNINITIALIZED:
[[fallthrough]];
case JS_TAG_CATCH_OFFSET:
JS_ThrowTypeError(ctx, "Expected type %s, got tag %d", QJSPP_TYPENAME(std::variant<Ts...>), tag);
[[fallthrough]];
case JS_TAG_EXCEPTION:
break;
case JS_TAG_BIG_DECIMAL:
[[fallthrough]];
case JS_TAG_BIG_FLOAT:
[[fallthrough]];
case JS_TAG_FLOAT64:
[[fallthrough]];
default: // more than JS_TAG_FLOAT64 (nan boxing)
return unwrapPriority<is_double, std::is_floating_point>(ctx, v);
}
throw exception{ctx};
}
};
template <typename T>
struct rest : std::vector<T>
{
using std::vector<T>::vector;
using std::vector<T>::operator=;
};
namespace detail {
/** Helper function to convert and then free JSValue. */
template <typename T>
T unwrap_free(JSContext * ctx, JSValue val)
{
if constexpr(std::is_same_v<T, void>)
{
JS_FreeValue(ctx, val);
return js_traits<T>::unwrap(ctx, val);
}
else
{
try
{
T result = js_traits<std::decay_t<T>>::unwrap(ctx, val);
JS_FreeValue(ctx, val);
return result;
}
catch(...)
{
JS_FreeValue(ctx, val);
throw;
}
}
}
template <typename T, size_t I, size_t NArgs>
struct unwrap_arg_impl {
static auto unwrap(JSContext * ctx, int argc, JSValueConst * argv)
{
if (size_t(argc) <= I) {
JS_ThrowTypeError(ctx, "Expected at least %lu arguments but received %d",
(unsigned long)NArgs, argc);
throw exception{ctx};
}
return js_traits<std::decay_t<T>>::unwrap(ctx, argv[I]);
}
};
template <typename T, size_t I, size_t NArgs>
struct unwrap_arg_impl<rest<T>, I, NArgs> {
static rest<T> unwrap(JSContext * ctx, int argc, JSValueConst * argv) {
static_assert(I == NArgs - 1, "The `rest` argument must be the last function argument.");
rest<T> result;
result.reserve(argc - I);
for (size_t i = I; i < size_t(argc); ++i)
result.push_back(js_traits<T>::unwrap(ctx, argv[i]));
return result;
}
};
template <class Tuple, std::size_t... I>
Tuple unwrap_args_impl(JSContext * ctx, int argc, JSValueConst * argv, std::index_sequence<I...>)
{
return Tuple{unwrap_arg_impl<std::tuple_element_t<I, Tuple>, I, sizeof...(I)>::unwrap(ctx, argc, argv)...};
}
/** Helper function to convert an array of JSValues to a tuple.
* @tparam Args C++ types of the argv array
*/
template <typename... Args>
std::tuple<std::decay_t<Args>...> unwrap_args(JSContext * ctx, int argc, JSValueConst * argv)
{
return unwrap_args_impl<std::tuple<std::decay_t<Args>...>>(ctx, argc, argv, std::make_index_sequence<sizeof...(Args)>());
}
/** Helper function to call f with an array of JSValues.
* @tparam R return type of f
* @tparam Args argument types of f
* @tparam Callable type of f (inferred)
* @param ctx JSContext
* @param f callable object
* @param argv array of JSValue's
* @return converted return value of f or JS_NULL if f returns void
*/
template <typename R, typename... Args, typename Callable>
JSValue wrap_call(JSContext * ctx, Callable&& f, int argc, JSValueConst * argv) noexcept
{
try
{
if constexpr(std::is_same_v<R, void>)
{
std::apply(std::forward<Callable>(f), unwrap_args<Args...>(ctx, argc, argv));
return JS_NULL;
}
else
{
return js_traits<std::decay_t<R>>::wrap(ctx,
std::apply(std::forward<Callable>(f),
unwrap_args<Args...>(ctx, argc, argv)));
}
}
catch(exception)
{
return JS_EXCEPTION;
}
catch (std::exception const & err)
{
JS_ThrowInternalError(ctx, "%s", err.what());
return JS_EXCEPTION;
}
catch (...)
{
JS_ThrowInternalError(ctx, "Unknown error");
return JS_EXCEPTION;
}
}
/** Same as wrap_call, but pass this_value as first argument.
* @tparam FirstArg type of this_value
*/
template <typename R, typename FirstArg, typename... Args, typename Callable>
JSValue wrap_this_call(JSContext * ctx, Callable&& f, JSValueConst this_value, int argc, JSValueConst * argv) noexcept
{
try
{
if constexpr(std::is_same_v<R, void>)
{
std::apply(std::forward<Callable>(f), std::tuple_cat(unwrap_args<FirstArg>(ctx, 1, &this_value),
unwrap_args<Args...>(ctx, argc, argv)));
return JS_NULL;
}
else
{
return js_traits<std::decay_t<R>>::wrap(ctx,
std::apply(std::forward<Callable>(f),
std::tuple_cat(
unwrap_args<FirstArg>(ctx, 1, &this_value),
unwrap_args<Args...>(ctx, argc, argv))));
}
}
catch(exception)
{
return JS_EXCEPTION;
}
catch (std::exception const & err)
{
JS_ThrowInternalError(ctx, "%s", err.what());
return JS_EXCEPTION;
}
catch (...)
{
JS_ThrowInternalError(ctx, "Unknown error");
return JS_EXCEPTION;
}
}
template <class Tuple, std::size_t... I>
void wrap_args_impl(JSContext * ctx, JSValue * argv, Tuple tuple, std::index_sequence<I...>)
{
((argv[I] = js_traits<std::decay_t<std::tuple_element_t<I, Tuple>>>::wrap(ctx, std::get<I>(tuple))), ...);
}
/** Converts C++ args to JSValue array.
* @tparam Args argument types
* @param argv array of size at least sizeof...(Args)
*/
template <typename... Args>
void wrap_args(JSContext * ctx, JSValue * argv, Args&& ... args)
{
wrap_args_impl(ctx, argv, std::make_tuple(std::forward<Args>(args)...),
std::make_index_sequence<sizeof...(Args)>());
}
// Helper trait to obtain `T` in `T::*` expressions
template<typename T> struct class_from_member_pointer { using type = void; };
template<typename T, typename U> struct class_from_member_pointer<T U::*> { using type = U; };
template<typename T> using class_from_member_pointer_t = typename class_from_member_pointer<T>::type;
} // namespace detail
/** A wrapper type for free and class member functions.
* Pointer to function F is a template argument.
* @tparam F either a pointer to free function or a pointer to class member function
* @tparam PassThis if true and F is a pointer to free function, passes Javascript "this" value as first argument:
*/
template <auto F, bool PassThis = false /* pass this as the first argument */>
struct fwrapper
{
/// "name" property of the JS function object (not defined if nullptr)
const char * name = nullptr;
};
/** Conversion to JSValue for free function in fwrapper. */
template <typename R, typename... Args, R (* F)(Args...), bool PassThis>
struct js_traits<fwrapper<F, PassThis>>
{
static JSValue wrap(JSContext * ctx, fwrapper<F, PassThis> fw) noexcept
{
return JS_NewCFunction(ctx, [](JSContext * ctx, JSValueConst this_value, int argc,
JSValueConst * argv) noexcept -> JSValue {
if constexpr(PassThis)
return detail::wrap_this_call<R, Args...>(ctx, F, this_value, argc, argv);
else
return detail::wrap_call<R, Args...>(ctx, F, argc, argv);
}, fw.name, sizeof...(Args));
}
};
/** Conversion to JSValue for class member function in fwrapper. PassThis is ignored and treated as true */
template <typename R, class T, typename... Args, R (T::*F)(Args...), bool PassThis/*=ignored*/>
struct js_traits<fwrapper<F, PassThis>>
{
static JSValue wrap(JSContext * ctx, fwrapper<F, PassThis> fw) noexcept
{
return JS_NewCFunction(ctx, [](JSContext * ctx, JSValueConst this_value, int argc,
JSValueConst * argv) noexcept -> JSValue {
return detail::wrap_this_call<R, std::shared_ptr<T>, Args...>(ctx, F, this_value, argc, argv);
}, fw.name, sizeof...(Args));
}
};
/** Conversion to JSValue for const class member function in fwrapper. PassThis is ignored and treated as true */
template <typename R, class T, typename... Args, R (T::*F)(Args...) const, bool PassThis/*=ignored*/>
struct js_traits<fwrapper<F, PassThis>>
{
static JSValue wrap(JSContext * ctx, fwrapper<F, PassThis> fw) noexcept
{
return JS_NewCFunction(ctx, [](JSContext * ctx, JSValueConst this_value, int argc,
JSValueConst * argv) noexcept -> JSValue {
return detail::wrap_this_call<R, std::shared_ptr<T>, Args...>(ctx, F, this_value, argc, argv);
}, fw.name, sizeof...(Args));
}
};
/** A wrapper type for constructor of type T with arguments Args.
* Compilation fails if no such constructor is defined.
* @tparam Args constructor arguments
*/
template <class T, typename... Args>
struct ctor_wrapper
{
static_assert(std::is_constructible<T, Args...>::value, "no such constructor!");
/// "name" property of JS constructor object
const char * name = nullptr;
};
namespace detail {
/// equivalent to JS_GetPropertyStr(ctx, this_value, "prototype");
inline JSValue GetPropertyPrototype(JSContext * ctx, JSValueConst this_value)
{
// constant atom: doesn't need to be freed and doesn't change with context
static const JSAtom JS_ATOM_prototype = JS_NewAtom(ctx, "prototype");
return JS_GetProperty(ctx, this_value, JS_ATOM_prototype);
}
} // namespace detail
/** Conversion to JSValue for ctor_wrapper. */
template <class T, typename... Args>
struct js_traits<ctor_wrapper<T, Args...>>
{
static JSValue wrap(JSContext * ctx, ctor_wrapper<T, Args...> cw) noexcept
{
return JS_NewCFunction2(ctx, [](JSContext * ctx, JSValueConst this_value, int argc,
JSValueConst * argv) noexcept -> JSValue {
if(js_traits<std::shared_ptr<T>>::QJSClassId == 0) // not registered
{
#if defined(__cpp_rtti)
// automatically register class on first use (no prototype)
js_traits<std::shared_ptr<T>>::register_class(ctx, typeid(T).name());
#else
JS_ThrowTypeError(ctx, "quickjspp ctor_wrapper<T>::wrap: Class is not registered");
return JS_EXCEPTION;
#endif
}
auto proto = detail::GetPropertyPrototype(ctx, this_value);
if(JS_IsException(proto))
return proto;
auto jsobj = JS_NewObjectProtoClass(ctx, proto, js_traits<std::shared_ptr<T>>::QJSClassId);
JS_FreeValue(ctx, proto);
if(JS_IsException(jsobj))
return jsobj;
try
{
std::shared_ptr<T> ptr = std::apply(std::make_shared<T, Args...>, detail::unwrap_args<Args...>(ctx, argc, argv));
JS_SetOpaque(jsobj, new std::shared_ptr<T>(std::move(ptr)));
return jsobj;
}
catch (exception)
{
JS_FreeValue(ctx, jsobj);
return JS_EXCEPTION;
}
catch (std::exception const & err)
{
JS_FreeValue(ctx, jsobj);
JS_ThrowInternalError(ctx, "%s", err.what());
return JS_EXCEPTION;
}
catch (...)
{
JS_FreeValue(ctx, jsobj);
JS_ThrowInternalError(ctx, "Unknown error");
return JS_EXCEPTION;
}
// return detail::wrap_call<std::shared_ptr<T>, Args...>(ctx, std::make_shared<T, Args...>, argv);
}, cw.name, sizeof...(Args), JS_CFUNC_constructor, 0);
}
};
/** Conversions for std::shared_ptr<T>. Empty shared_ptr corresponds to JS_NULL.
* T should be registered to a context before conversions.
* @tparam T class type
*/
template <class T>
struct js_traits<std::shared_ptr<T>>
{
/// Registered class id in QuickJS.
inline static JSClassID QJSClassId = 0;
/// Signature of the function to obtain the std::shared_ptr from the JSValue.
using ptr_cast_fcn_t = std::function<std::shared_ptr<T>(JSContext*, JSValueConst)>;
/// Used by registerDerivedClass to register new derived classes with this class' base type.
inline static std::function<void(JSClassID, ptr_cast_fcn_t)> registerWithBase;
/// Mapping between derived class' JSClassID and function to obtain the std::shared_ptr from the JSValue.
inline static std::unordered_map<JSClassID, ptr_cast_fcn_t> ptrCastFcnMap;
/** Register a class as a derived class.
*
* @tparam D type of the derived class
* @param derived_class_id class id of the derived class
* @param ptr_cast_fcn function to obtain a std::shared_ptr from the JSValue
*/
template<typename D>
static void registerDerivedClass(JSClassID derived_class_id, ptr_cast_fcn_t ptr_cast_fcn) {
static_assert(std::is_base_of<T,D>::value && !std::is_same<T,D>::value, "Type is not a derived class");
using derived_ptr_cast_fcn_t = typename js_traits<std::shared_ptr<D>>::ptr_cast_fcn_t;
// Register how to obtain the std::shared_ptr from the derived class.
ptrCastFcnMap[derived_class_id] = ptr_cast_fcn;
// Propagate the registration to our base class (if any).
if (registerWithBase) registerWithBase(derived_class_id, ptr_cast_fcn);
// Instrument the derived class so that it can propagate new derived classes to us.
auto old_registerWithBase = js_traits<std::shared_ptr<D>>::registerWithBase;
js_traits<std::shared_ptr<D>>::registerWithBase =
[old_registerWithBase = std::move(old_registerWithBase)]
(JSClassID derived_class_id, derived_ptr_cast_fcn_t derived_ptr_cast_fcn){
if (old_registerWithBase) old_registerWithBase(derived_class_id, derived_ptr_cast_fcn);
registerDerivedClass<D>(derived_class_id, [derived_cast_fcn = std::move(derived_ptr_cast_fcn)](JSContext * ctx, JSValueConst v) {
return std::shared_ptr<T>(derived_cast_fcn(ctx, v));
});
};
}
template <typename B>
static
std::enable_if_t<std::is_same_v<B, T> || std::is_same_v<B, void>>
ensureCanCastToBase() { }
template <typename B>
static
std::enable_if_t<!std::is_same_v<B, T> && !std::is_same_v<B, void>>
ensureCanCastToBase() {
static_assert(std::is_base_of_v<B, T>, "Type is not a derived class");
if(js_traits<std::shared_ptr<T>>::QJSClassId == 0)
JS_NewClassID(&js_traits<std::shared_ptr<T>>::QJSClassId);
js_traits<std::shared_ptr<B>>::template registerDerivedClass<T>(QJSClassId, unwrap);
}
template <auto M>
static void ensureCanCastToBase() {
ensureCanCastToBase<detail::class_from_member_pointer_t<decltype(M)>>();
}
/** Stores offsets to qjs::Value members of T.
* These values should be marked by class_registrar::mark for QuickJS garbage collector
* so that the cycle removal algorithm can find the other objects referenced by this object.
*/
static inline std::vector<Value T::*> markOffsets;
/** Register class in QuickJS context.
*
* @param ctx context
* @param name class name
* @param proto class prototype or JS_NULL
* @param call QJS call function. see quickjs doc
* @param exotic pointer to QJS exotic methods(static lifetime) which allow custom property handling. see quickjs doc
* @throws exception
*/
static void register_class(JSContext * ctx, const char * name, JSValue proto = JS_NULL,
JSClassCall * call = nullptr, JSClassExoticMethods * exotic = nullptr)
{
if(QJSClassId == 0)
{
JS_NewClassID(&QJSClassId);
}
auto rt = JS_GetRuntime(ctx);
if(!JS_IsRegisteredClass(rt, QJSClassId))
{
JSClassGCMark * marker = nullptr;
if(!markOffsets.empty())
{
marker = [](JSRuntime *rt, JSValueConst val, JS_MarkFunc *mark_func) {
auto pptr = static_cast<std::shared_ptr<T> *>(JS_GetOpaque(val, QJSClassId));
assert(pptr);
const T * ptr = pptr->get();
assert(ptr);
for(Value T::* member : markOffsets)
{
JS_MarkValue(rt, (*ptr.*member).v, mark_func);
}
};
}
JSClassDef def{
name,
// destructor (finalizer)
[](JSRuntime * rt, JSValue obj) noexcept {
auto pptr = static_cast<std::shared_ptr<T> *>(JS_GetOpaque(obj, QJSClassId));
delete pptr;
},
// mark
marker,
// call
call,
// exotic
exotic
};
int e = JS_NewClass(rt, QJSClassId, &def);
if(e < 0)
{
JS_ThrowInternalError(ctx, "Can't register class %s", name);
throw exception{ctx};
}
}
JS_SetClassProto(ctx, QJSClassId, proto);
}
/** Create a JSValue from std::shared_ptr<T>.
* Creates an object with class if #QJSClassId and sets its opaque pointer to a new copy of #ptr.
*/
static JSValue wrap(JSContext * ctx, std::shared_ptr<T> ptr)
{
if(!ptr)
return JS_NULL;
if(QJSClassId == 0) // not registered
{
#if defined(__cpp_rtti)
// automatically register class on first use (no prototype)
register_class(ctx, typeid(T).name());
#else
JS_ThrowTypeError(ctx, "quickjspp std::shared_ptr<T>::wrap: Class is not registered");
return JS_EXCEPTION;
#endif
}
auto jsobj = JS_NewObjectClass(ctx, QJSClassId);
if(JS_IsException(jsobj))
return jsobj;
auto pptr = new std::shared_ptr<T>(std::move(ptr));
JS_SetOpaque(jsobj, pptr);
return jsobj;
}
/// @throws exception if #v doesn't have the correct class id
static std::shared_ptr<T> unwrap(JSContext * ctx, JSValueConst v)
{
std::shared_ptr<T> ptr = nullptr;
if (JS_IsNull(v)) {
return ptr;
}
auto obj_class_id = JS_GetClassID(v);
if (obj_class_id == QJSClassId) {
// The JS object is of class T
void * opaque = JS_GetOpaque2(ctx, v, obj_class_id);
assert(opaque && "No opaque pointer in object");
ptr = *static_cast<std::shared_ptr<T> *>(opaque);
} else if (ptrCastFcnMap.count(obj_class_id)) {
// The JS object is of a class derived from T
ptr = ptrCastFcnMap[obj_class_id](ctx, v);
} else {
// The JS object does not derives from T
JS_ThrowTypeError(ctx, "Expected type %s, got object with classid %d",
QJSPP_TYPENAME(T), obj_class_id);
throw exception{ctx};
}
if(!ptr) {
JS_ThrowInternalError(ctx, "Object's opaque pointer is NULL");
throw exception{ctx};
}
return ptr;
}
};
/** Conversions for non-owning pointers to class T. nullptr corresponds to JS_NULL.
* @tparam T class type
*/
template <class T>
struct js_traits<T *, std::enable_if_t<std::is_class_v<T>>>
{
static JSValue wrap(JSContext * ctx, T * ptr)
{
if (ptr == nullptr) {
return JS_NULL;
}
if(js_traits<std::shared_ptr<T>>::QJSClassId == 0) // not registered
{
#if defined(__cpp_rtti)
// If you have an error here with T=JSValueConst
// it probably means you are passing JSValueConst to where JSValue is expected
js_traits<std::shared_ptr<T>>::register_class(ctx, typeid(T).name());
#else
JS_ThrowTypeError(ctx, "quickjspp js_traits<T *>::wrap: Class is not registered");
return JS_EXCEPTION;
#endif
}
auto jsobj = JS_NewObjectClass(ctx, js_traits<std::shared_ptr<T>>::QJSClassId);
if(JS_IsException(jsobj))
return jsobj;
// shared_ptr with empty deleter since we don't own T*
auto pptr = new std::shared_ptr<T>(ptr, [](T *) {});
JS_SetOpaque(jsobj, pptr);
return jsobj;
}
static T * unwrap(JSContext * ctx, JSValueConst v)
{
if (JS_IsNull(v)) {
return nullptr;
}
auto ptr = js_traits<std::shared_ptr<T>>::unwrap(ctx, v);
return ptr.get();
}
};
/** Conversions for enums. */
template <typename E>
struct js_traits<E, std::enable_if_t<std::is_enum_v<E>>> {
using T = std::underlying_type_t<E>;
static E unwrap(JSContext* ctx, JSValue v) noexcept {
return static_cast<E>(js_traits<T>::unwrap(ctx, v));
}
static JSValue wrap(JSContext* ctx, E t) noexcept {
return js_traits<T>::wrap(ctx, static_cast<T>(t));;
}
};
namespace detail {
/** A faster std::function-like object with type erasure.
* Used to convert any callable objects (including lambdas) to JSValue.
*/
struct function
{
JSValue
(* invoker)(function * self, JSContext * ctx, JSValueConst this_value, int argc, JSValueConst * argv) = nullptr;
void (* destroyer)(function * self) = nullptr;
alignas(std::max_align_t) char functor[];
template <typename Functor>
static function * create(JSRuntime * rt, Functor&& f)
{
using Functor_t = std::decay_t<Functor>;
auto fptr = static_cast<function *>(js_malloc_rt(rt, sizeof(function) + sizeof(Functor_t)));
if(!fptr)
throw std::bad_alloc{};
new(fptr) function;
auto functorptr = reinterpret_cast<Functor_t *>(fptr->functor);
new(functorptr) Functor_t(std::forward<Functor>(f));
fptr->destroyer = nullptr;
if constexpr(!std::is_trivially_destructible_v<Functor_t>)
{
fptr->destroyer = [](function * fptr) {
auto functorptr = reinterpret_cast<Functor_t *>(fptr->functor);
functorptr->~Functor_t();
};
}
return fptr;
}
};
static_assert(std::is_trivially_destructible_v<function>);
}
template <>
struct js_traits<detail::function>
{
inline static JSClassID QJSClassId = 0;
// TODO: replace ctx with rt
static void register_class(JSContext * ctx, const char * name)
{
if(QJSClassId == 0)
{
JS_NewClassID(&QJSClassId);
}
auto rt = JS_GetRuntime(ctx);
if(JS_IsRegisteredClass(rt, QJSClassId))
return;
JSClassDef def{
name,
// destructor
[](JSRuntime * rt, JSValue obj) noexcept {
auto fptr = static_cast<detail::function *>(JS_GetOpaque(obj, QJSClassId));
assert(fptr);
if(fptr->destroyer)
fptr->destroyer(fptr);
js_free_rt(rt, fptr);
},
nullptr, // mark
// call
[](JSContext * ctx, JSValueConst func_obj, JSValueConst this_val, int argc,
JSValueConst * argv, int flags) -> JSValue {
auto ptr = static_cast<detail::function *>(JS_GetOpaque2(ctx, func_obj, QJSClassId));
if(!ptr)
return JS_EXCEPTION;
return ptr->invoker(ptr, ctx, this_val, argc, argv);
},
nullptr
};
int e = JS_NewClass(rt, QJSClassId, &def);
if(e < 0)
throw std::runtime_error{"Cannot register C++ function class"};
}
};
/** Traits for accessing object properties.
* @tparam Key property key type (uint32 and strings are supported)
*/
template <typename Key>
struct js_property_traits
{
static void set_property(JSContext * ctx, JSValue this_obj, Key key, JSValue value);
static JSValue get_property(JSContext * ctx, JSValue this_obj, Key key);
};
template <>
struct js_property_traits<const char *>
{
static void set_property(JSContext * ctx, JSValue this_obj, const char * name, JSValue value)
{
int err = JS_SetPropertyStr(ctx, this_obj, name, value);
if(err < 0)
throw exception{ctx};
}
static JSValue get_property(JSContext * ctx, JSValue this_obj, const char * name) noexcept
{
return JS_GetPropertyStr(ctx, this_obj, name);
}
};
template <>
struct js_property_traits<uint32_t>
{
static void set_property(JSContext * ctx, JSValue this_obj, uint32_t idx, JSValue value)
{
int err = JS_SetPropertyUint32(ctx, this_obj, idx, value);
if(err < 0)
throw exception{ctx};
}
static JSValue get_property(JSContext * ctx, JSValue this_obj, uint32_t idx) noexcept
{
return JS_GetPropertyUint32(ctx, this_obj, idx);
}
};
template <>
struct js_property_traits<int> : js_property_traits<uint32_t> {};
namespace detail {
template <typename Key>
struct property_proxy
{
JSContext * ctx;
JSValue this_obj;
Key key;
/** Conversion helper function */
template <typename T>
T as() const
{
return unwrap_free<T>(ctx, js_property_traits<Key>::get_property(ctx, this_obj, key));
}
/** Explicit conversion operator (to any type) */
template <typename T>
explicit operator T() const { return as<T>(); }
/** Implicit converion to qjs::Value */
operator Value() const; // defined later due to Value being incomplete type
/// noncopyable
property_proxy& operator =(property_proxy) = delete;
template <typename T>
property_proxy& operator =(T&& value)
{
js_property_traits<Key>::set_property(ctx, this_obj, key,
js_traits<std::decay_t<T>>::wrap(ctx, std::forward<T>(value)));
return *this;
}
template <typename Key2>
property_proxy<Key2> operator[](Key2 key2) const
{
return {ctx, as<JSValue>(), std::move(key2)};
}
~property_proxy() noexcept { JS_FreeValue(ctx, this_obj); }
};
// class member variable getter/setter
template <auto M>
struct get_set {};
// M - member object
template <class T, typename R, R T::*M>
struct get_set<M>
{
using is_const = std::is_const<R>;
static const R& get(std::shared_ptr<T> ptr)
{
return *ptr.*M;
}
static R& set(std::shared_ptr<T> ptr, R value)
{
return *ptr.*M = std::move(value);
}
};
// M - static member object
template <typename R, R *M>
struct get_set<M>
{
using is_const = std::is_const<R>;
static const R& get(bool)
{
return *M;
}
static R& set(bool, R value)
{
return *M = std::move(value);
}
};
} // namespace detail
/** JSValue with RAAI semantics.
* A wrapper over (JSValue v, JSContext * ctx).
* Calls JS_FreeValue(ctx, v) on destruction. Can be copied and moved.
* A JSValue can be released by either JSValue x = std::move(value); or JSValue x = value.release(), then the Value becomes invalid and FreeValue won't be called
* Can be converted to C++ type, for example: auto string = value.as<std::string>(); qjs::exception would be thrown on error
* Properties can be accessed (read/write): value["property1"] = 1; value[2] = "2";
*/
class Value
{
public:
JSValue v;
JSContext * ctx = nullptr;
public:
/** Use context.newValue(val) instead */
template <typename T>
Value(JSContext * ctx, T&& val) : ctx(ctx)
{
v = js_traits<std::decay_t<T>>::wrap(ctx, std::forward<T>(val));
if(JS_IsException(v))
throw exception{ctx};
}
Value(JSValue&& v) noexcept : v(std::move(v)), ctx(nullptr) {}
Value(const Value& rhs) noexcept
{
ctx = rhs.ctx;
v = JS_DupValue(ctx, rhs.v);
}
Value(Value&& rhs) noexcept
{
std::swap(ctx, rhs.ctx);
v = rhs.v;
}
Value& operator =(Value rhs) noexcept
{
std::swap(ctx, rhs.ctx);
std::swap(v, rhs.v);
return *this;
}
bool operator ==(JSValueConst other) const
{
return JS_VALUE_GET_TAG(v) == JS_VALUE_GET_TAG(other) && JS_VALUE_GET_PTR(v) == JS_VALUE_GET_PTR(other);
}
bool operator !=(JSValueConst other) const { return !((*this) == other); }
/** Returns true if 2 values are the same (equality for arithmetic types or point to the same object) */
bool operator ==(const Value& rhs) const
{
return (*this == rhs.v);
}
bool operator !=(const Value& rhs) const { return !((*this) == rhs); }
~Value()
{
if(ctx) JS_FreeValue(ctx, v);
}
bool isError() const { return JS_IsError(ctx, v); }
/** Conversion helper function: value.as<T>()
* @tparam T type to convert to
* @return type returned by js_traits<std::decay_t<T>>::unwrap that should be implicitly convertible to T
* */
template <typename T>
auto as() const { return js_traits<std::decay_t<T>>::unwrap(ctx, v); }
/** Explicit conversion: static_cast<T>(value) or (T)value */
template <typename T>
explicit operator T() const { return as<T>(); }
JSValue release() noexcept// dont call freevalue
{
ctx = nullptr;
return v;
}
/** Implicit conversion to JSValue (rvalue only). Example: JSValue v = std::move(value); */
operator JSValue()&& noexcept { return release(); }
/** Access JS properties. Returns proxy type which is implicitly convertible to qjs::Value */
template <typename Key>
detail::property_proxy<Key> operator [](Key key)
{
assert(ctx && "Trying to access properties of Value with no JSContext");
return {ctx, JS_DupValue(ctx, v), std::move(key)};
}
// add("f", []() {...});
template <typename Function>
Value& add(const char * name, Function&& f)
{
(*this)[name] = js_traits<decltype(std::function{std::forward<Function>(f)})>::wrap(ctx,
std::forward<Function>(f));
return *this;
}
// add<&f>("f");
// add<&T::f>("f");
template <auto F>
std::enable_if_t<std::is_member_function_pointer_v<decltype(F)> || std::is_function_v<std::remove_pointer_t<decltype(F)>>, Value&>
add(const char * name)
{
(*this)[name] = fwrapper<F>{name};
return *this;
}
// add_getter_setter<&T::get_member, &T::set_member>("member");
template <auto FGet, auto FSet>
Value& add_getter_setter(const char * name)
{
auto prop = JS_NewAtom(ctx, name);
using fgetter = fwrapper<FGet, true>;
using fsetter = fwrapper<FSet, true>;
int ret = JS_DefinePropertyGetSet(ctx, v, prop,
js_traits<fgetter>::wrap(ctx, fgetter{name}),
js_traits<fsetter>::wrap(ctx, fsetter{name}),
JS_PROP_CONFIGURABLE | JS_PROP_WRITABLE | JS_PROP_ENUMERABLE
);
JS_FreeAtom(ctx, prop);
if(ret < 0)
throw exception{ctx};
return *this;
}
// add_getter<&T::get_member>("member");
template <auto FGet>
Value& add_getter(const char * name)
{
auto prop = JS_NewAtom(ctx, name);
using fgetter = fwrapper<FGet, true>;
int ret = JS_DefinePropertyGetSet(ctx, v, prop,
js_traits<fgetter>::wrap(ctx, fgetter{name}),
JS_UNDEFINED,
JS_PROP_CONFIGURABLE | JS_PROP_ENUMERABLE
);
JS_FreeAtom(ctx, prop);
if(ret < 0)
throw exception{ctx};
return *this;
}
// add<&T::member>("member");
template <auto M>
std::enable_if_t<std::is_member_object_pointer_v<decltype(M)>, Value&>
add(const char * name)
{
if constexpr (detail::get_set<M>::is_const::value)
return add_getter<detail::get_set<M>::get>(name);
else
return add_getter_setter<detail::get_set<M>::get, detail::get_set<M>::set>(name);
}
// add<&T::static_member>("static_member");
template <auto M>
std::enable_if_t<std::is_pointer_v<decltype(M)> && !std::is_function_v<std::remove_pointer_t<decltype(M)>> , Value&>
add(const char * name)
{
if constexpr (detail::get_set<M>::is_const::value)
return add_getter<detail::get_set<M>::get>(name);
else
return add_getter_setter<detail::get_set<M>::get, detail::get_set<M>::set>(name);
}
std::string
toJSON(const Value& replacer = JS_UNDEFINED, const Value& space = JS_UNDEFINED)
{
assert(ctx);
assert(!replacer.ctx || ctx == replacer.ctx);
assert(!space.ctx || ctx == space.ctx);
return (std::string) Value{ctx, JS_JSONStringify(ctx, v, replacer.v, space.v)};
}
/** same as Context::eval() but with this Value as 'this' */
Value evalThis(std::string_view buffer, const char * filename = "<evalThis>", int flags = 0)
{
assert(buffer.data()[buffer.size()] == '\0' && "eval buffer is not null-terminated"); // JS_Eval requirement
assert(ctx);
return Value{ctx, JS_EvalThis(ctx, v, buffer.data(), buffer.size(), filename, flags)};
}
};
/** Thin wrapper over JSRuntime * rt
* Calls JS_FreeRuntime on destruction. noncopyable.
*/
class Runtime
{
public:
JSRuntime * rt;
Runtime()
{
rt = JS_NewRuntime();
if(!rt)
throw std::runtime_error{"qjs: Cannot create runtime"};
JS_SetHostUnhandledPromiseRejectionTracker(rt, promise_unhandled_rejection_tracker, NULL);
JS_SetModuleLoaderFunc(rt, nullptr, module_loader, nullptr);
}
// noncopyable
Runtime(const Runtime&) = delete;
~Runtime()
{
JS_FreeRuntime(rt);
}
/// @return pointer to qjs::Context of the executed job or nullptr if no job is pending
Context * executePendingJob();
bool isJobPending() const {
return JS_IsJobPending(rt);
}
private:
static void promise_unhandled_rejection_tracker(JSContext *ctx, JSValueConst promise,
JSValueConst reason, JS_BOOL is_handled, void *opaque);
static JSModuleDef *module_loader(JSContext *ctx,
const char *module_name, void *opaque);
};
namespace detail {
inline std::optional<std::string> readFile(std::filesystem::path const & filepath)
{
if (!std::filesystem::exists(filepath)) return std::nullopt;
std::ifstream f(filepath, std::ios::in | std::ios::binary);
if (!f.is_open()) return std::nullopt;
std::stringstream sstream;
sstream << f.rdbuf();
return sstream.str();
}
inline std::string toUri(std::string_view filename) {
auto fname = std::string{filename};
if (fname.find("://") < fname.find("/")) return fname;
auto fpath = std::filesystem::path(fname);
if (!fpath.is_absolute()) {
fpath = "." / fpath;
}
fpath = std::filesystem::weakly_canonical(fpath);
fname = "file://" + fpath.generic_string();
return fname;
}
}
/** Wrapper over JSContext * ctx
* Calls JS_SetContextOpaque(ctx, this); on construction and JS_FreeContext on destruction
*/
class Context
{
public:
JSContext * ctx;
/** Module wrapper
* Workaround for lack of opaque pointer for module load function by keeping a list of modules in qjs::Context.
*/
class Module
{
friend class Context;
JSModuleDef * m;
JSContext * ctx;
const char * name;
using nvp = std::pair<const char *, Value>;
std::vector<nvp> exports;
public:
Module(JSContext * ctx, const char * name) : ctx(ctx), name(name)
{
m = JS_NewCModule(ctx, name, [](JSContext * ctx, JSModuleDef * m) noexcept {
auto& context = Context::get(ctx);
auto it = std::find_if(context.modules.begin(), context.modules.end(),
[m](const Module& module) { return module.m == m; });
if(it == context.modules.end())
return -1;
for(const auto& e : it->exports)
{
if(JS_SetModuleExport(ctx, m, e.first, JS_DupValue(ctx, e.second.v)) != 0)
return -1;
}
return 0;
});
if(!m)
throw exception{ctx};
}
Module& add(const char * name, JSValue&& value)
{
exports.push_back({name, {ctx, std::move(value)}});
JS_AddModuleExport(ctx, m, name);
return *this;
}
template <typename T>
Module& add(const char * name, T&& value)
{
return add(name, js_traits<T>::wrap(ctx, std::forward<T>(value)));
}
Module(const Module&) = delete;
Module(Module&&) = default;
//Module& operator=(Module&&) = default;
// function wrappers
/** Add free function F.
* Example:
* module.function<static_cast<double (*)(double)>(&::sin)>("sin");
*/
template <auto F>
Module& function(const char * name)
{
return add(name, qjs::fwrapper<F>{name});
}
/** Add function object f.
* Slower than template version.
* Example: module.function("sin", [](double x) { return ::sin(x); });
*/
template <typename F>
Module& function(const char * name, F&& f)
{
return add(name, js_traits<decltype(std::function{std::forward<F>(f)})>::wrap(ctx, std::forward<F>(f)));
}
// class register wrapper
private:
/** Helper class to register class members and constructors.
* See fun, constructor.
* Actual registration occurs at object destruction.
*/
template <class T>
class class_registrar
{
const char * name;
qjs::Value prototype;
qjs::Context::Module& module;
qjs::Context& context;
qjs::Value ctor; // last added constructor
public:
explicit class_registrar(const char * name, qjs::Context::Module& module, qjs::Context& context) :
name(name),
prototype(context.newObject()),
module(module),
context(context),
ctor(JS_NULL)
{
}
class_registrar(const class_registrar&) = delete;
/** Add functional object f
*/
template <typename F>
class_registrar& fun(const char * name, F&& f)
{
prototype[name] = std::forward<F>(f);
return *this;
}
/** Add class member function or class member variable F
* Example:
* struct T { int var; int func(); }
* auto& module = context.addModule("module");
* module.class_<T>("T").fun<&T::var>("var").fun<&T::func>("func");
*/
template <auto F>
class_registrar& fun(const char * name)
{
js_traits<std::shared_ptr<T>>::template ensureCanCastToBase<F>();
prototype.add<F>(name);
return *this;
}
/** Add a static member or function to the last added constructor.
* Example:
* struct T { static int var; static int func(); }
* module.class_<T>("T").contructor<>("T").static_fun<&T::var>("var").static_fun<&T::func>("func");
*/
template <auto F>
class_registrar& static_fun(const char * name)
{
assert(!JS_IsNull(ctor.v) && "You should call .constructor before .static_fun");
js_traits<qjs::shared_ptr<T>>::template ensureCanCastToBase<F>();
ctor.add<F>(name);
return *this;
}
/** Add a property with custom getter and setter.
* Example:
* module.class_<T>("T").property<&T::getX, &T::setX>("x");
*/
template <auto FGet, auto FSet = nullptr>
class_registrar& property(const char * name)
{
js_traits<std::shared_ptr<T>>::template ensureCanCastToBase<FGet>();
js_traits<std::shared_ptr<T>>::template ensureCanCastToBase<FSet>();
if constexpr (std::is_same_v<decltype(FSet), std::nullptr_t>)
prototype.add_getter<FGet>(name);
else
prototype.add_getter_setter<FGet, FSet>(name);
return *this;
}
/** Add class constructor
* @tparam Args contructor arguments
* @param name constructor name (if not specified class name will be used)
*/
template <typename... Args>
class_registrar& constructor(const char * name = nullptr)
{
if(!name)
name = this->name;
ctor = context.newValue(qjs::ctor_wrapper<T, Args...>{name});
JS_SetConstructor(context.ctx, ctor.v, prototype.v);
module.add(name, qjs::Value{ctor});
return *this;
}
/** Sets the base class
* @tparam B base class
*/
template <class B>
class_registrar& base()
{
static_assert(!std::is_same_v<B, T>, "Type cannot be a base of itself");
assert(js_traits<std::shared_ptr<B>>::QJSClassId && "base class is not registered");
js_traits<std::shared_ptr<T>>::template ensureCanCastToBase<B>();
auto base_proto = JS_GetClassProto(context.ctx, js_traits<std::shared_ptr<B>>::QJSClassId);
int err = JS_SetPrototype(context.ctx, prototype.v, base_proto);
JS_FreeValue(context.ctx, base_proto);
if(err < 0)
throw exception{context.ctx};
return *this;
}
/** All qjs::Value members of T should be marked by mark<> for QuickJS garbage collector
* so that the cycle removal algorithm can find the other objects referenced by this object.
*/
template <Value T::* V>
class_registrar& mark()
{
js_traits<std::shared_ptr<T>>::markOffsets.push_back(V);
return *this;
}
~class_registrar()
{
context.registerClass<T>(name, std::move(prototype));
}
};
public:
/** Add class to module.
* See \ref class_registrar.
*/
template <class T>
class_registrar<T> class_(const char * name)
{
return class_registrar<T>{name, *this, qjs::Context::get(ctx)};
}
};
std::vector<Module> modules;
private:
void init()
{
JS_SetContextOpaque(ctx, this);
js_traits<detail::function>::register_class(ctx, "C++ function");
}
public:
Context(Runtime& rt) : Context(rt.rt) {}
Context(JSRuntime * rt)
{
ctx = JS_NewContext(rt);
if(!ctx)
throw std::runtime_error{"qjs: Cannot create context"};
init();
}
Context(JSContext * ctx) : ctx{ctx}
{
init();
}
// noncopyable
Context(const Context&) = delete;
~Context()
{
modules.clear();
JS_FreeContext(ctx);
}
/** Callback triggered when a Promise rejection won't ever be handled */
std::function<void(Value)> onUnhandledPromiseRejection;
/** Data type returned by the moduleLoader function */
struct ModuleData {
std::optional<std::string> source, url;
ModuleData() : source(std::nullopt), url(std::nullopt) {}
ModuleData(std::optional<std::string> source) : source(std::move(source)), url(std::nullopt) {}
ModuleData(std::optional<std::string> url, std::optional<std::string> source) : source(std::move(source)), url(std::move(url)) {}
};
/** Function called to obtain the source of a module */
std::function<ModuleData(std::string_view)> moduleLoader =
[](std::string_view filename) -> ModuleData {
return ModuleData{ detail::toUri(filename), detail::readFile(filename) };
};
template <typename Function>
void enqueueJob(Function && job);
/** Create module and return a reference to it */
Module& addModule(const char * name)
{
modules.emplace_back(ctx, name);
return modules.back();
}
/** returns globalThis */
Value global() { return Value{ctx, JS_GetGlobalObject(ctx)}; }
/** returns new Object() */
Value newObject() { return Value{ctx, JS_NewObject(ctx)}; }
/** returns JS value converted from c++ object val */
template <typename T>
Value newValue(T&& val) { return Value{ctx, std::forward<T>(val)}; }
/** returns current exception associated with context and clears it. Should be called when qjs::exception is caught */
Value getException() { return Value{ctx, JS_GetException(ctx)}; }
/** Register class T for conversions to/from std::shared_ptr<T> to work.
* Wherever possible module.class_<T>("T")... should be used instead.
* @tparam T class type
* @param name class name in JS engine
* @param proto JS class prototype or JS_UNDEFINED
*/
template <class T>
void registerClass(const char * name, JSValue proto = JS_NULL)
{
js_traits<std::shared_ptr<T>>::register_class(ctx, name, proto);
}
/// @see JS_Eval
Value eval(std::string_view buffer, const char * filename = "<eval>", int flags = 0)
{
assert(buffer.data()[buffer.size()] == '\0' && "eval buffer is not null-terminated"); // JS_Eval requirement
JSValue v = JS_Eval(ctx, buffer.data(), buffer.size(), filename, flags);
return Value{ctx, std::move(v)};
}
Value evalFile(const char * filename, int flags = 0)
{
auto buf = detail::readFile(filename);
if (!buf)
throw std::runtime_error{std::string{"evalFile: can't read file: "} + filename};
return eval(*buf, filename, flags);
}
/// @see JS_ParseJSON2
Value fromJSON(std::string_view buffer, const char * filename = "<fromJSON>", int flags = 0)
{
assert(buffer.data()[buffer.size()] == '\0' &&
"fromJSON buffer is not null-terminated"); // JS_ParseJSON requirement
return Value{ctx, JS_ParseJSON2(ctx, buffer.data(), buffer.size(), filename, flags)};
}
/** Get qjs::Context from JSContext opaque pointer */
static Context& get(JSContext * ctx)
{
void * ptr = JS_GetContextOpaque(ctx);
assert(ptr);
return *static_cast<Context *>(ptr);
}
};
/** Conversion traits for Value.
*/
template <>
struct js_traits<Value>
{
static Value unwrap(JSContext * ctx, JSValueConst v)
{
return Value{ctx, JS_DupValue(ctx, v)};
}
static JSValue wrap(JSContext * ctx, Value v) noexcept
{
assert(JS_GetRuntime(ctx) == JS_GetRuntime(v.ctx));
return v.release();
}
};
/** Convert to/from std::function. Actually accepts/returns callable object that is compatible with function<R (Args...)>.
* @tparam R return type
* @tparam Args argument types
*/
template <typename R, typename... Args>
struct js_traits<std::function<R(Args...)>, int>
{
static auto unwrap(JSContext * ctx, JSValueConst fun_obj)
{
const int argc = sizeof...(Args);
if constexpr(argc == 0)
{
return [jsfun_obj = Value{ctx, JS_DupValue(ctx, fun_obj)}]() -> R {
JSValue result = JS_Call(jsfun_obj.ctx, jsfun_obj.v, JS_UNDEFINED, 0, nullptr);
if(JS_IsException(result))
throw exception{jsfun_obj.ctx};
return detail::unwrap_free<R>(jsfun_obj.ctx, result);
};
}
else
{
return [jsfun_obj = Value{ctx, JS_DupValue(ctx, fun_obj)}](Args ... args) -> R {
const int argc = sizeof...(Args);
JSValue argv[argc];
detail::wrap_args(jsfun_obj.ctx, argv, std::forward<Args>(args)...);
JSValue result = JS_Call(jsfun_obj.ctx, jsfun_obj.v, JS_UNDEFINED, argc,
const_cast<JSValueConst *>(argv));
for(int i = 0; i < argc; i++) JS_FreeValue(jsfun_obj.ctx, argv[i]);
if(JS_IsException(result))
throw exception{jsfun_obj.ctx};
return detail::unwrap_free<R>(jsfun_obj.ctx, result);
};
}
}
/** Convert from function object functor to JSValue.
* Uses detail::function for type-erasure.
*/
template <typename Functor>
static JSValue wrap(JSContext * ctx, Functor&& functor) noexcept
{
using detail::function;
assert(js_traits<function>::QJSClassId);
auto obj = JS_NewObjectClass(ctx, js_traits<function>::QJSClassId);
if(JS_IsException(obj))
return obj;
try
{
auto fptr = function::create(JS_GetRuntime(ctx), std::forward<Functor>(functor));
fptr->invoker = [](function * self, JSContext * ctx, JSValueConst this_value, int argc,
JSValueConst * argv) {
assert(self);
auto f = reinterpret_cast<std::decay_t<Functor> *>(&self->functor);
return detail::wrap_call<R, Args...>(ctx, *f, argc, argv);
};
JS_SetOpaque(obj, fptr);
return obj;
}
catch(const std::exception& e)
{
JS_ThrowInternalError(ctx, "%s", e.what());
return JS_EXCEPTION;
}
catch(...)
{
JS_ThrowInternalError(ctx, "Unknown errror");
return JS_EXCEPTION;
}
}
};
namespace detail {
template<typename T, typename = void>
struct is_callable : std::is_function<T> { };
template<typename T>
struct is_callable<T, std::enable_if_t<std::is_same_v<decltype(void(&T::operator())), void>>> : std::true_type { };
template<typename T>
inline constexpr bool is_callable_v = is_callable<T>::value;
}
template <typename Function>
struct js_traits<Function, std::enable_if_t<detail::is_callable_v<Function>>> {
static auto unwrap(JSContext * ctx, JSValueConst fun_obj)
{
return js_traits<
decltype(std::function{std::declval<Function>()}),
int
>::unwrap(ctx, fun_obj);
}
template <typename Functor>
static JSValue wrap(JSContext * ctx, Functor&& functor)
{
return js_traits<
decltype(std::function{std::declval<Function>()}),
int
>::wrap(ctx, std::forward<Functor>(functor));
}
};
/** Convert from std::vector<T> to Array and vice-versa. If Array holds objects that are non-convertible to T throws qjs::exception */
template <class T>
struct js_traits<std::vector<T>>
{
static JSValue wrap(JSContext * ctx, const std::vector<T>& arr) noexcept
{
try
{
auto jsarray = Value{ctx, JS_NewArray(ctx)};
for(uint32_t i = 0; i < (uint32_t) arr.size(); i++)
jsarray[i] = arr[i];
return jsarray.release();
}
catch(exception)
{
return JS_EXCEPTION;
}
catch (std::exception const & err)
{
JS_ThrowInternalError(ctx, "%s", err.what());
return JS_EXCEPTION;
}
catch (...)
{
JS_ThrowInternalError(ctx, "Unknown error");
return JS_EXCEPTION;
}
}
static std::vector<T> unwrap(JSContext * ctx, JSValueConst jsarr)
{
int e = JS_IsArray(ctx, jsarr);
if(e == 0)
JS_ThrowTypeError(ctx, "js_traits<std::vector<T>>::unwrap expects array");
if(e <= 0)
throw exception{ctx};
Value jsarray{ctx, JS_DupValue(ctx, jsarr)};
std::vector<T> arr;
auto len = static_cast<int32_t>(jsarray["length"]);
arr.reserve((uint32_t) len);
for(uint32_t i = 0; i < (uint32_t) len; i++)
arr.push_back(static_cast<T>(jsarray[i]));
return arr;
}
};
template <typename U, typename V>
struct js_traits<std::pair<U, V>>
{
static JSValue wrap(JSContext * ctx, std::pair<U, V> obj) noexcept
{
try
{
auto jsarray = Value{ctx, JS_NewArray(ctx)};
jsarray[uint32_t(0)] = std::move(obj.first);
jsarray[uint32_t(1)] = std::move(obj.second);
return jsarray.release();
}
catch(exception)
{
return JS_EXCEPTION;
}
catch (std::exception const & err)
{
JS_ThrowInternalError(ctx, "%s", err.what());
return JS_EXCEPTION;
}
catch (...)
{
JS_ThrowInternalError(ctx, "Unknown error");
return JS_EXCEPTION;
}
}
static std::pair<U, V> unwrap(JSContext * ctx, JSValueConst jsarr)
{
int e = JS_IsArray(ctx, jsarr);
if(e == 0)
JS_ThrowTypeError(ctx, "js_traits<%s>::unwrap expects array", QJSPP_TYPENAME(std::pair<U, V>));
if(e <= 0)
throw exception{ctx};
Value jsarray{ctx, JS_DupValue(ctx, jsarr)};
const auto len = static_cast<uint32_t>(jsarray["length"]);
if(len != 2)
{
JS_ThrowTypeError(ctx, "js_traits<%s>::unwrap expected array of length 2, got length %d",
QJSPP_TYPENAME(std::pair<U, V>), len);
throw exception{ctx};
}
return std::pair<U, V>{
static_cast<U>(jsarray[uint32_t(0)]),
static_cast<V>(jsarray[uint32_t(1)])
};
}
};
/** Conversions for std::optional.
* Unlike other types does not throw on unwrap but returns nullopt.
* Converts std::nullopt to null.
*/
template <typename T>
struct js_traits<std::optional<T>>
{
/** Wraps T or null. */
static JSValue wrap(JSContext * ctx, std::optional<T> obj) noexcept
{
if(obj)
return js_traits<std::decay_t<T>>::wrap(ctx, *obj);
return JS_NULL;
}
/** If conversion to T fails returns std::nullopt. */
static auto unwrap(JSContext * ctx, JSValueConst v) noexcept -> std::optional<decltype(js_traits<std::decay_t<T>>::unwrap(ctx, v))>
{
try
{
if(JS_IsNull(v))
return std::nullopt;
return js_traits<std::decay_t<T>>::unwrap(ctx, v);
}
catch(exception)
{
// ignore and clear exception
JS_FreeValue(ctx, JS_GetException(ctx));
}
return std::nullopt;
}
};
namespace detail {
template <typename Key>
property_proxy<Key>::operator Value() const
{
return as<Value>();
}
}
template <typename Function>
void Context::enqueueJob(Function && job) {
JSValue job_val = js_traits<std::function<void()>>::wrap(ctx, std::forward<Function>(job));
JSValueConst arg = job_val;
int err = JS_EnqueueJob(ctx, [](JSContext *ctx, int argc, JSValueConst *argv){
try
{
assert(argc >= 1);
js_traits<std::function<void()>>::unwrap(ctx, argv[0])();
}
catch (exception)
{
return JS_EXCEPTION;
}
catch (std::exception const & err)
{
JS_ThrowInternalError(ctx, "%s", err.what());
return JS_EXCEPTION;
}
catch (...)
{
JS_ThrowInternalError(ctx, "Unknown error");
return JS_EXCEPTION;
}
return JS_UNDEFINED;
}, 1, &arg);
JS_FreeValue(ctx, job_val);
if(err < 0)
throw exception{ctx};
}
inline Context & exception::context() const {
return Context::get(ctx);
}
inline Value exception::get() {
return context().getException();
}
inline void Runtime::promise_unhandled_rejection_tracker(JSContext *ctx, JSValueConst promise,
JSValueConst reason, JS_BOOL is_handled, void *opaque)
{
auto & context = Context::get(ctx);
if (context.onUnhandledPromiseRejection) {
context.onUnhandledPromiseRejection(context.newValue(JS_DupValue(ctx, reason)));
}
}
inline JSModuleDef * Runtime::module_loader(JSContext *ctx,
const char *module_name, void *opaque)
{
Context::ModuleData data;
auto & context = Context::get(ctx);
try {
if (context.moduleLoader) data = context.moduleLoader(module_name);
if (!data.source) {
JS_ThrowReferenceError(ctx, "could not load module filename '%s'", module_name);
return NULL;
}
if (!data.url) data.url = module_name;
// compile the module
auto func_val = context.eval(*data.source, module_name, JS_EVAL_TYPE_MODULE | JS_EVAL_FLAG_COMPILE_ONLY);
assert(JS_VALUE_GET_TAG(func_val.v) == JS_TAG_MODULE);
JSModuleDef * m = reinterpret_cast<JSModuleDef *>(JS_VALUE_GET_PTR(func_val.v));
// set import.meta
auto meta = context.newValue(JS_GetImportMeta(ctx, m));
meta["url"] = *data.url;
meta["main"] = false;
return m;
}
catch(exception)
{
return NULL;
}
catch (std::exception const & err)
{
JS_ThrowInternalError(ctx, "%s", err.what());
return NULL;
}
catch (...)
{
JS_ThrowInternalError(ctx, "Unknown error");
return NULL;
}
}
inline Context * Runtime::executePendingJob() {
JSContext * ctx;
auto err = JS_ExecutePendingJob(rt, &ctx);
if (err == 0) {
// There was no job to run
return nullptr;
} else if (err < 0) {
throw exception{ctx};
}
return &Context::get(ctx);
}
} // namespace qjs