Elfspy/HookImpl.h

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2016-09-16 17:45:35 +02:00
#ifndef ELFSPY_HOOKIMPL_H
#define ELFSPY_HOOKIMPL_H
#include "elfspy/HookBase.h"
namespace spy
{
/**
* @namespace spy
* @class HookImpl
* Part of the Hook implementation to distinguish between void and non-void
* return values.
*/
template <typename CRTP, typename ReturnType, typename... ArgTypes>
class HookImpl : public HookBase<CRTP, ReturnType, ArgTypes...>
{
public:
/// @return collection to register thunks that process return value
static std::vector<Thunk<ReturnType&&>*>& return_thunks();
protected:
static std::vector<Thunk<ReturnType&&>*> return_thunks_;
static ReturnType&& use_return(ReturnType&& result);
static ReturnType thunk(ArgTypes... args);
using Base = HookBase<CRTP, ReturnType, ArgTypes...>;
};
template <typename CRTP, typename ReturnType, typename... ArgTypes>
std::vector<Thunk<ReturnType&&>*>
HookImpl<CRTP, ReturnType, ArgTypes...>::return_thunks_;
template <typename CRTP, typename ReturnType, typename... ArgTypes>
inline std::vector<Thunk<ReturnType&&>*>&
HookImpl<CRTP, ReturnType, ArgTypes...>::return_thunks()
{
return return_thunks_;
}
template <typename CRTP, typename ReturnType, typename... ArgTypes>
ReturnType&&
HookImpl<CRTP, ReturnType, ArgTypes...>::use_return(ReturnType&& result)
{
for (auto trap : return_thunks_)
{
trap->invoke(std::forward<ReturnType>(result));
}
return std::forward<ReturnType>(result);
}
template <typename CRTP, typename ReturnType, typename... ArgTypes>
ReturnType HookImpl<CRTP, ReturnType, ArgTypes...>::thunk(ArgTypes... args)
{
Base::run_thunks(std::forward<ArgTypes>(args)...);
return use_return(
std::forward<ReturnType>((*Base::patch_)(std::forward<ArgTypes>(args)...)));
}
/// specialisation for void return
template <typename CRTP, typename... ArgTypes>
class HookImpl<CRTP, void, ArgTypes...>
: public HookBase<CRTP, void, ArgTypes...>
{
protected:
static void thunk(ArgTypes... args);
private:
using Base = HookBase<CRTP, void, ArgTypes...>;
};
template <typename CRTP, typename... ArgTypes>
void HookImpl<CRTP, void, ArgTypes...>::thunk(ArgTypes... args)
{
Base::run_thunks(std::forward<ArgTypes>(args)...);
(*Base::patch_)(std::forward<ArgTypes>(args)...);
}
} // namespace spy
#endif