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util/BindMethod: simplify MakeBindFunctionWrapper()

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Max Kellermann 2021-12-02 23:25:40 +01:00 committed by Max Kellermann
parent 7e4ba3cb72
commit acab731fef
1 changed files with 21 additions and 41 deletions
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62
src/util/BindMethod.hxx
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@ -125,14 +125,16 @@ struct MethodSignatureHelper<R (T::*)(Args...) noexcept(NoExcept)> {
};
/**
* Helper class which converts a plain function signature type to a
* wrapper function pointer type.
* Helper class which converts a function pointer to a wrapper
* function pointer type.
*/
template<typename S>
struct MethodWrapperWithSignature;
struct FunctionSignatureHelper;
template<typename R, bool NoExcept, typename... Args>
struct MethodWrapperWithSignature<R(Args...) noexcept(NoExcept)> {
struct FunctionSignatureHelper<R (*)(Args...) noexcept(NoExcept)> {
typedef R plain_signature(Args...) noexcept(NoExcept);
typedef R (*function_pointer)(void *instance,
Args...) noexcept(NoExcept);
};
@ -161,52 +163,27 @@ MakeBindMethodWrapper() noexcept
return BindMethodWrapperGenerator<decltype(method), method>::Invoke;
}
/**
* Helper class which introspects a function pointer type.
*
* @param S the function type
*/
template<typename S>
struct FunctionTraits;
template<typename R, bool NoExcept, typename... Args>
struct FunctionTraits<R(Args...) noexcept(NoExcept)> {
/**
* A function type which describes the "plain" function
* signature.
*/
typedef R function_type(Args...) noexcept(NoExcept);
/**
* A function pointer type which describes the "plain"
* function signature.
*/
typedef R (*pointer)(Args...) noexcept(NoExcept);
};
/**
* Generate a wrapper function.
*
* @param S the plain function signature type
* @param P the plain function pointer type
* @param F the function pointer type
* @param function the function pointer
*/
template<typename S, auto function>
template<typename F, auto function>
struct BindFunctionWrapperGenerator;
template<auto function, bool NoExcept, typename R, typename... Args>
struct BindFunctionWrapperGenerator<R(Args...) noexcept(NoExcept), function> {
struct BindFunctionWrapperGenerator<R (*)(Args...) noexcept(NoExcept), function> {
static R Invoke(void *, Args... args) noexcept(NoExcept) {
return function(std::forward<Args>(args)...);
}
};
template<typename T, typename T::pointer function>
typename MethodWrapperWithSignature<typename T::function_type>::function_pointer
template<auto function>
typename FunctionSignatureHelper<decltype(function)>::function_pointer
MakeBindFunctionWrapper() noexcept
{
return BindFunctionWrapperGenerator<typename T::function_type,
function>::Invoke;
return BindFunctionWrapperGenerator<decltype(function), function>::Invoke;
}
} /* namespace BindMethodDetail */
@ -245,15 +222,18 @@ BindMethod(typename BindMethodDetail::MethodSignatureHelper<decltype(method)>::c
/**
* Construct a #BoundMethod instance for a plain function.
*
* @param T the #FunctionTraits class
* @param function the function pointer
*/
template<typename T, typename T::pointer function>
constexpr BoundMethod<typename T::function_type>
template<auto function>
constexpr auto
BindFunction() noexcept
{
return BoundMethod<typename T::function_type>(nullptr,
BindMethodDetail::MakeBindFunctionWrapper<T, function>());
using H = BindMethodDetail::FunctionSignatureHelper<decltype(function)>;
using plain_signature = typename H::plain_signature;
return BoundMethod<plain_signature>{
nullptr,
BindMethodDetail::MakeBindFunctionWrapper<function>(),
};
}
/**
@ -261,4 +241,4 @@ BindFunction() noexcept
* #BoundMethod instance.
*/
#define BIND_FUNCTION(function) \
BindFunction<typename BindMethodDetail::FunctionTraits<decltype(function)>, &function>()
BindFunction<&function>()