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/*
* Copyright (C) 2016-2019 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <memory>
#include <wtf/FastMalloc.h>
#include <wtf/Forward.h>
namespace WTF {
namespace Detail {
template<typename Out, typename... In>
class CallableWrapperBase {
WTF_MAKE_FAST_ALLOCATED;
public:
virtual ~CallableWrapperBase() { }
virtual Out call(In...) = 0;
};
template<typename, typename, typename...> class CallableWrapper;
template<typename CallableType, typename Out, typename... In>
class CallableWrapper : public CallableWrapperBase<Out, In...> {
public:
explicit CallableWrapper(CallableType&& callable)
: m_callable(WTFMove(callable)) { }
CallableWrapper(const CallableWrapper&) = delete;
CallableWrapper& operator=(const CallableWrapper&) = delete;
Out call(In... in) final { return m_callable(std::forward<In>(in)...); }
private:
CallableType m_callable;
};
} // namespace Detail
template<typename Out, typename... In> Function<Out(In...)> adopt(Detail::CallableWrapperBase<Out, In...>*);
template <typename Out, typename... In>
class Function<Out(In...)> {
WTF_MAKE_FAST_ALLOCATED;
public:
using Impl = Detail::CallableWrapperBase<Out, In...>;
Function() = default;
Function(std::nullptr_t) { }
template<typename CallableType, class = typename std::enable_if<!(std::is_pointer<CallableType>::value && std::is_function<typename std::remove_pointer<CallableType>::type>::value) && std::is_rvalue_reference<CallableType&&>::value>::type>
Function(CallableType&& callable)
: m_callableWrapper(makeUnique<Detail::CallableWrapper<CallableType, Out, In...>>(std::forward<CallableType>(callable))) { }
template<typename FunctionType, class = typename std::enable_if<std::is_pointer<FunctionType>::value && std::is_function<typename std::remove_pointer<FunctionType>::type>::value>::type>
Function(FunctionType f)
: m_callableWrapper(makeUnique<Detail::CallableWrapper<FunctionType, Out, In...>>(std::forward<FunctionType>(f))) { }
Out operator()(In... in) const
{
ASSERT(m_callableWrapper);
return m_callableWrapper->call(std::forward<In>(in)...);
}
explicit operator bool() const { return !!m_callableWrapper; }
template<typename CallableType, class = typename std::enable_if<!(std::is_pointer<CallableType>::value && std::is_function<typename std::remove_pointer<CallableType>::type>::value) && std::is_rvalue_reference<CallableType&&>::value>::type>
Function& operator=(CallableType&& callable)
{
m_callableWrapper = makeUnique<Detail::CallableWrapper<CallableType, Out, In...>>(std::forward<CallableType>(callable));
return *this;
}
template<typename FunctionType, class = typename std::enable_if<std::is_pointer<FunctionType>::value && std::is_function<typename std::remove_pointer<FunctionType>::type>::value>::type>
Function& operator=(FunctionType f)
{
m_callableWrapper = makeUnique<Detail::CallableWrapper<FunctionType, Out, In...>>(std::forward<FunctionType>(f));
return *this;
}
Function& operator=(std::nullptr_t)
{
m_callableWrapper = nullptr;
return *this;
}
Impl* leak()
{
return m_callableWrapper.release();
}
private:
enum AdoptTag { Adopt };
Function(Impl* impl, AdoptTag)
: m_callableWrapper(impl)
{
}
friend Function adopt<Out, In...>(Impl*);
std::unique_ptr<Impl> m_callableWrapper;
};
template<typename Out, typename... In> Function<Out(In...)> adopt(Detail::CallableWrapperBase<Out, In...>* impl)
{
return Function<Out(In...)>(impl, Function<Out(In...)>::Adopt);
}
} // namespace WTF
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