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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
#ifndef nsFunctionInterfaceUtils_h
#define nsFunctionInterfaceUtils_h
#include "mozilla/RefPtr.h"
#include "nsINamed.h"
#include "nsISupports.h"
#include "nsString.h"
class nsFunctionInterfaceBase : public nsINamed {
public:
NS_DECL_THREADSAFE_ISUPPORTS
NS_DECL_NSINAMED
explicit nsFunctionInterfaceBase(const nsLiteralCString& aName)
: mName(aName) {}
protected:
virtual ~nsFunctionInterfaceBase() = default;
private:
const nsLiteralCString mName;
};
template <class F, class I>
class nsFunctionInterface : public nsFunctionInterfaceBase, public I {
public:
explicit nsFunctionInterface(const nsLiteralCString& aName, F&& aInvocable)
: nsFunctionInterfaceBase(aName),
mInvocable(std::forward<F>(aInvocable)) {}
NS_IMETHOD_(MozExternalRefCountType) AddRef(void) final {
return nsFunctionInterfaceBase::AddRef();
}
NS_IMETHOD_(MozExternalRefCountType) Release(void) final {
return nsFunctionInterfaceBase::Release();
}
NS_IMETHOD QueryInterface(REFNSIID aIID, void** aPtr) final {
if (aIID.Equals(NS_GET_IID(I))) {
*aPtr = do_AddRef(static_cast<I*>(this)).take();
return NS_OK;
}
return nsFunctionInterfaceBase::QueryInterface(aIID, aPtr);
}
protected:
virtual ~nsFunctionInterface() = default;
// Wrapper around std::invoke which converts `void` return types to `NS_OK`,
// as a small QOL improvement for infallible callback implementations.
template <class... Args>
nsresult Invoke(Args&&... aArgs) {
using ReturnType = std::invoke_result_t<std::decay_t<F>&, Args...>;
if constexpr (std::is_void_v<ReturnType>) {
std::invoke(mInvocable, std::forward<Args>(aArgs)...);
return NS_OK;
} else {
return std::invoke(mInvocable, std::forward<Args>(aArgs)...);
}
}
MOZ_NO_UNIQUE_ADDRESS std::decay_t<F> mInvocable;
};
#endif // nsFunctionInterfaceUtils_h