/*
- * Copyright 2017-present Facebook, Inc.
+ * Copyright 2016-present Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include <folly/CppAttributes.h>
#include <folly/Portability.h>
#include <folly/Traits.h>
+#include <folly/functional/Invoke.h>
namespace folly {
Function<ReturnType(Args...) const> constCastFunction(
Function<ReturnType(Args...)>&&) noexcept;
+#if FOLLY_HAVE_NOEXCEPT_FUNCTION_TYPE
+template <typename ReturnType, typename... Args>
+Function<ReturnType(Args...) const noexcept> constCastFunction(
+ Function<ReturnType(Args...) noexcept>&&) noexcept;
+#endif
+
namespace detail {
namespace function {
std::aligned_storage<6 * sizeof(void*)>::type tiny;
};
-template <typename Fun, typename FunT = typename std::decay<Fun>::type>
+template <typename Fun, typename = Fun*>
using IsSmall = Conjunction<
- std::integral_constant<bool, (sizeof(FunT) <= sizeof(Data::tiny))>,
- std::is_nothrow_move_constructible<FunT>>;
+ std::integral_constant<bool, (sizeof(Fun) <= sizeof(Data::tiny))>,
+ std::is_nothrow_move_constructible<Fun>>;
using SmallTag = std::true_type;
using HeapTag = std::false_type;
-template <class T>
+template <typename T>
struct NotFunction : std::true_type {};
-template <class T>
+template <typename T>
struct NotFunction<Function<T>> : std::false_type {};
-template <typename Fun, typename FunT = typename std::decay<Fun>::type>
-using DecayIfConstructible = typename std::enable_if<
- Conjunction<NotFunction<FunT>, std::is_constructible<FunT, Fun>>::value,
- FunT>::type;
+template <typename T>
+using EnableIfNotFunction =
+ typename std::enable_if<NotFunction<T>::value>::type;
struct CoerceTag {};
return false;
}
+template <typename F, typename... Args>
+using CallableResult = decltype(std::declval<F>()(std::declval<Args>()...));
+
+template <
+ typename From,
+ typename To,
+ typename = typename std::enable_if<
+ !std::is_reference<To>::value || std::is_reference<From>::value>::type>
+using SafeResultOf = decltype(static_cast<To>(std::declval<From>()));
+
template <typename FunctionType>
struct FunctionTraits;
using NonConstSignature = ReturnType(Args...);
using OtherSignature = ConstSignature;
- template <typename F, typename G = typename std::decay<F>::type>
- using ResultOf = decltype(
- static_cast<ReturnType>(std::declval<G&>()(std::declval<Args>()...)));
+ template <typename F>
+ using ResultOf =
+ SafeResultOf<CallableResult<_t<std::decay<F>>&, Args...>, ReturnType>;
template <typename Fun>
static ReturnType callSmall(Data& p, Args&&... args) {
}
ReturnType operator()(Args... args) {
- auto& fn = *static_cast<Function<ReturnType(Args...)>*>(this);
+ auto& fn = *static_cast<Function<NonConstSignature>*>(this);
return fn.call_(fn.data_, static_cast<Args&&>(args)...);
}
class SharedProxy {
- std::shared_ptr<Function<ReturnType(Args...)>> sp_;
+ std::shared_ptr<Function<NonConstSignature>> sp_;
public:
- explicit SharedProxy(Function<ReturnType(Args...)>&& func)
- : sp_(std::make_shared<Function<ReturnType(Args...)>>(
- std::move(func))) {}
+ explicit SharedProxy(Function<NonConstSignature>&& func)
+ : sp_(std::make_shared<Function<NonConstSignature>>(std::move(func))) {}
ReturnType operator()(Args&&... args) const {
return (*sp_)(static_cast<Args&&>(args)...);
}
using NonConstSignature = ReturnType(Args...);
using OtherSignature = NonConstSignature;
- template <typename F, typename G = typename std::decay<F>::type>
- using ResultOf = decltype(static_cast<ReturnType>(
- std::declval<const G&>()(std::declval<Args>()...)));
+ template <typename F>
+ using ResultOf = SafeResultOf<
+ CallableResult<const _t<std::decay<F>>&, Args...>,
+ ReturnType>;
template <typename Fun>
static ReturnType callSmall(Data& p, Args&&... args) {
}
ReturnType operator()(Args... args) const {
- auto& fn = *static_cast<const Function<ReturnType(Args...) const>*>(this);
+ auto& fn = *static_cast<const Function<ConstSignature>*>(this);
+ return fn.call_(fn.data_, static_cast<Args&&>(args)...);
+ }
+
+ class SharedProxy {
+ std::shared_ptr<Function<ConstSignature>> sp_;
+
+ public:
+ explicit SharedProxy(Function<ConstSignature>&& func)
+ : sp_(std::make_shared<Function<ConstSignature>>(std::move(func))) {}
+ ReturnType operator()(Args&&... args) const {
+ return (*sp_)(static_cast<Args&&>(args)...);
+ }
+ };
+};
+
+#if FOLLY_HAVE_NOEXCEPT_FUNCTION_TYPE
+template <typename ReturnType, typename... Args>
+struct FunctionTraits<ReturnType(Args...) noexcept> {
+ using Call = ReturnType (*)(Data&, Args&&...) noexcept;
+ using IsConst = std::false_type;
+ using ConstSignature = ReturnType(Args...) const noexcept;
+ using NonConstSignature = ReturnType(Args...) noexcept;
+ using OtherSignature = ConstSignature;
+
+ template <typename F>
+ using ResultOf =
+ SafeResultOf<CallableResult<_t<std::decay<F>>&, Args...>, ReturnType>;
+
+ template <typename Fun>
+ static ReturnType callSmall(Data& p, Args&&... args) noexcept {
+ return static_cast<ReturnType>((*static_cast<Fun*>(
+ static_cast<void*>(&p.tiny)))(static_cast<Args&&>(args)...));
+ }
+
+ template <typename Fun>
+ static ReturnType callBig(Data& p, Args&&... args) noexcept {
+ return static_cast<ReturnType>(
+ (*static_cast<Fun*>(p.big))(static_cast<Args&&>(args)...));
+ }
+
+ static ReturnType uninitCall(Data&, Args&&...) noexcept {
+ throw std::bad_function_call();
+ }
+
+ ReturnType operator()(Args... args) noexcept {
+ auto& fn = *static_cast<Function<NonConstSignature>*>(this);
+ return fn.call_(fn.data_, static_cast<Args&&>(args)...);
+ }
+
+ class SharedProxy {
+ std::shared_ptr<Function<NonConstSignature>> sp_;
+
+ public:
+ explicit SharedProxy(Function<NonConstSignature>&& func)
+ : sp_(std::make_shared<Function<NonConstSignature>>(std::move(func))) {}
+ ReturnType operator()(Args&&... args) const {
+ return (*sp_)(static_cast<Args&&>(args)...);
+ }
+ };
+};
+
+template <typename ReturnType, typename... Args>
+struct FunctionTraits<ReturnType(Args...) const noexcept> {
+ using Call = ReturnType (*)(Data&, Args&&...) noexcept;
+ using IsConst = std::true_type;
+ using ConstSignature = ReturnType(Args...) const noexcept;
+ using NonConstSignature = ReturnType(Args...) noexcept;
+ using OtherSignature = NonConstSignature;
+
+ template <typename F>
+ using ResultOf = SafeResultOf<
+ CallableResult<const _t<std::decay<F>>&, Args...>,
+ ReturnType>;
+
+ template <typename Fun>
+ static ReturnType callSmall(Data& p, Args&&... args) noexcept {
+ return static_cast<ReturnType>((*static_cast<const Fun*>(
+ static_cast<void*>(&p.tiny)))(static_cast<Args&&>(args)...));
+ }
+
+ template <typename Fun>
+ static ReturnType callBig(Data& p, Args&&... args) noexcept {
+ return static_cast<ReturnType>(
+ (*static_cast<const Fun*>(p.big))(static_cast<Args&&>(args)...));
+ }
+
+ static ReturnType uninitCall(Data&, Args&&...) noexcept {
+ throw std::bad_function_call();
+ }
+
+ ReturnType operator()(Args... args) const noexcept {
+ auto& fn = *static_cast<const Function<ConstSignature>*>(this);
return fn.call_(fn.data_, static_cast<Args&&>(args)...);
}
class SharedProxy {
- std::shared_ptr<Function<ReturnType(Args...) const>> sp_;
+ std::shared_ptr<Function<ConstSignature>> sp_;
public:
- explicit SharedProxy(Function<ReturnType(Args...) const>&& func)
- : sp_(std::make_shared<Function<ReturnType(Args...) const>>(
- std::move(func))) {}
+ explicit SharedProxy(Function<ConstSignature>&& func)
+ : sp_(std::make_shared<Function<ConstSignature>>(std::move(func))) {}
ReturnType operator()(Args&&... args) const {
return (*sp_)(static_cast<Args&&>(args)...);
}
};
};
+#endif
template <typename Fun>
bool execSmall(Op o, Data* src, Data* dst) {
return true;
}
-// Invoke helper
-template <typename F, typename... Args>
-inline auto invoke(F&& f, Args&&... args)
- -> decltype(std::forward<F>(f)(std::forward<Args>(args)...)) {
- return std::forward<F>(f)(std::forward<Args>(args)...);
-}
-
-template <typename M, typename C, typename... Args>
-inline auto invoke(M(C::*d), Args&&... args)
- -> decltype(std::mem_fn(d)(std::forward<Args>(args)...)) {
- return std::mem_fn(d)(std::forward<Args>(args)...);
-}
-
} // namespace function
} // namespace detail
// invoking undefined behavior. Const-correctness is only violated when
// `FunctionType` is a const function type (e.g., `int() const`) and `*this`
// is the result of calling `constCastFunction`.
- mutable Data data_;
+ mutable Data data_{};
Call call_{&Traits::uninitCall};
Exec exec_{&detail::function::uninitNoop};
// not copyable
Function(const Function&) = delete;
+#if __OBJC__
+ // Make sure Objective C blocks are copied
+ template <class ReturnType, class... Args>
+ /*implicit*/ Function(ReturnType (^objCBlock)(Args... args))
+ : Function([blockCopy = (ReturnType (^)(Args...))[objCBlock copy]](
+ Args... args) { return blockCopy(args...); }){};
+#endif
+
/**
* Move constructor
*/
* signature matches (i.e. it returns an object convertible to `R` when called
* with `Args...`).
*
- * \note `typename = ResultOf<Fun>` prevents this overload from being
- * selected by overload resolution when `fun` is not a compatible function.
+ * \note `typename Traits::template ResultOf<Fun>` prevents this overload
+ * from being selected by overload resolution when `fun` is not a compatible
+ * function.
*
- * \note The noexcept requires some explanation. IsSmall is true when the
+ * \note The noexcept requires some explanation. `IsSmall` is true when the
* decayed type fits within the internal buffer and is noexcept-movable. But
* this ctor might copy, not move. What we need here, if this ctor does a
* copy, is that this ctor be noexcept when the copy is noexcept. That is not
- * checked in IsSmall, and shouldn't be, because once the Function is
+ * checked in `IsSmall`, and shouldn't be, because once the `Function` is
* constructed, the contained object is never copied. This check is for this
* ctor only, in the case that this ctor does a copy.
*/
template <
typename Fun,
- typename FunT = detail::function::DecayIfConstructible<Fun>,
+ typename = detail::function::EnableIfNotFunction<Fun>,
typename = typename Traits::template ResultOf<Fun>>
- /* implicit */ Function(Fun&& fun) noexcept(
- IsSmall<Fun>::value && noexcept(FunT(std::declval<Fun>())))
- : Function(static_cast<Fun&&>(fun), IsSmall<Fun>{}) {}
+ /* implicit */ Function(Fun fun) noexcept(
+ IsSmall<Fun>::value && noexcept(Fun(std::declval<Fun>())))
+ : Function(std::move(fun), IsSmall<Fun>{}) {}
/**
* For move-constructing from a `folly::Function<X(Ys...) [const?]>`.
Function& operator=(const Function&) = delete;
+#if __OBJC__
+ // Make sure Objective C blocks are copied
+ template <class ReturnType, class... Args>
+ /* implicit */ Function &operator=(ReturnType (^objCBlock)(Args... args)) {
+ (*this) = [blockCopy = (ReturnType (^)(Args...))[objCBlock copy]](
+ Args... args) { return blockCopy(args...); };
+ return *this;
+ }
+#endif
+
/**
* Move assignment operator
*
* then `*this` is left in a valid but unspecified state.
*/
Function& operator=(Function&& that) noexcept {
- // Q: Why is is safe to destroy and reconstruct this object in place?
+ // Q: Why is it safe to destroy and reconstruct this object in place?
// A: Two reasons: First, `Function` is a final class, so in doing this
// we aren't slicing off any derived parts. And second, the move
// operation is guaranteed not to throw so we always leave the object
* Assigns a callable object to this `Function`. If the operation fails,
* `*this` is left unmodified.
*
- * \note `typename = ResultOf<Fun>` prevents this overload from being
- * selected by overload resolution when `fun` is not a compatible function.
+ * \note `typename = decltype(Function(std::declval<Fun>()))` prevents this
+ * overload from being selected by overload resolution when `fun` is not a
+ * compatible function.
*/
template <typename Fun, typename = decltype(Function(std::declval<Fun>()))>
- Function& operator=(Fun&& fun) noexcept(
+ Function& operator=(Fun fun) noexcept(
noexcept(/* implicit */ Function(std::declval<Fun>()))) {
// Doing this in place is more efficient when we can do so safely.
if (noexcept(/* implicit */ Function(std::declval<Fun>()))) {
// Q: Why is is safe to destroy and reconstruct this object in place?
// A: See the explanation in the move assignment operator.
this->~Function();
- ::new (this) Function(static_cast<Fun&&>(fun));
+ ::new (this) Function(std::move(fun));
} else {
// Construct a temporary and (nothrow) swap.
- Function(static_cast<Fun&&>(fun)).swap(*this);
+ Function(std::move(fun)).swap(*this);
}
return *this;
}
return std::move(that);
}
+#if FOLLY_HAVE_NOEXCEPT_FUNCTION_TYPE
+template <typename ReturnType, typename... Args>
+Function<ReturnType(Args...) const noexcept> constCastFunction(
+ Function<ReturnType(Args...) noexcept>&& that) noexcept {
+ return Function<ReturnType(Args...) const noexcept>{
+ std::move(that), detail::function::CoerceTag{}};
+}
+
+template <typename ReturnType, typename... Args>
+Function<ReturnType(Args...) const noexcept> constCastFunction(
+ Function<ReturnType(Args...) const noexcept>&& that) noexcept {
+ return std::move(that);
+}
+#endif
+
+namespace detail {
+namespace function {
+template <typename Fun, typename FunctionType, typename = void>
+struct IsCallableAsImpl : std::false_type {};
+
+template <typename Fun, typename ReturnType, typename... Args>
+struct IsCallableAsImpl<
+ Fun,
+ ReturnType(Args...),
+ void_t<typename std::result_of<Fun && (Args && ...)>::type>>
+ : std::is_convertible<
+ typename std::result_of<Fun && (Args && ...)>::type,
+ ReturnType> {};
+
+template <typename Fun, typename FunctionType>
+struct IsCallableAs : IsCallableAsImpl<Fun, FunctionType> {};
+} // namespace function
+} // namespace detail
+
/**
* @class FunctionRef
*
class FunctionRef<ReturnType(Args...)> final {
using Call = ReturnType (*)(void*, Args&&...);
- void* object_{nullptr};
- Call call_{&FunctionRef::uninitCall};
-
static ReturnType uninitCall(void*, Args&&...) {
throw std::bad_function_call();
}
template <typename Fun>
static ReturnType call(void* object, Args&&... args) {
- return static_cast<ReturnType>(detail::function::invoke(
- *static_cast<Fun*>(object), static_cast<Args&&>(args)...));
+ using Pointer = _t<std::add_pointer<Fun>>;
+ return static_cast<ReturnType>(invoke(
+ static_cast<Fun&&>(*static_cast<Pointer>(object)),
+ static_cast<Args&&>(args)...));
}
+ void* object_{nullptr};
+ Call call_{&FunctionRef::uninitCall};
+
public:
/**
* Default constructor. Constructs an empty FunctionRef.
template <
typename Fun,
typename std::enable_if<
- !std::is_same<FunctionRef, typename std::decay<Fun>::type>::value,
+ Conjunction<
+ Negation<std::is_same<FunctionRef, _t<std::decay<Fun>>>>,
+ detail::function::IsCallableAs<Fun, ReturnType(Args...)>>::value,
int>::type = 0>
- /* implicit */ FunctionRef(Fun&& fun) noexcept {
- using ReferencedType = typename std::remove_reference<Fun>::type;
-
- static_assert(
- std::is_convertible<
- typename std::result_of<ReferencedType&(Args && ...)>::type,
- ReturnType>::value,
- "FunctionRef cannot be constructed from object with "
- "incompatible function signature");
-
- // `Fun` may be a const type, in which case we have to do a const_cast
- // to store the address in a `void*`. This is safe because the `void*`
- // will be cast back to `Fun*` (which is a const pointer whenever `Fun`
- // is a const type) inside `FunctionRef::call`
- object_ = const_cast<void*>(static_cast<void const*>(std::addressof(fun)));
- call_ = &FunctionRef::call<ReferencedType>;
- }
+ constexpr /* implicit */ FunctionRef(Fun&& fun) noexcept
+ // `Fun` may be a const type, in which case we have to do a const_cast
+ // to store the address in a `void*`. This is safe because the `void*`
+ // will be cast back to `Fun*` (which is a const pointer whenever `Fun`
+ // is a const type) inside `FunctionRef::call`
+ : object_(
+ const_cast<void*>(static_cast<void const*>(std::addressof(fun)))),
+ call_(&FunctionRef::call<Fun>) {}
ReturnType operator()(Args... args) const {
return call_(object_, static_cast<Args&&>(args)...);
}
- explicit operator bool() const {
+ constexpr explicit operator bool() const {
return object_;
}
};
projects / folly.git / blobdiff