On Sep 12, 2012 8:06 PM, "Andrew Sandoval" <sandoval@netwaysglobal.com> wrote:
I'd like to propose a new Boost library for RAII wrapper classes that I think could be standardized to help promote the use of RAII. Though shared_ptr, scoped_ptr, etc. greatly enhance the use of RAII, I propose two additional classes.
The first of these is RAIIFunction
[snip] I remember proposing something like this a few years back. My proposal was not based on boost:: or std::function for efficiency reasons. It used capturing the scope guard object by reference to a base class. The general idea is shown in the end of my post. I think, performance is a critical factor for tools like this. Also, have you looked at Boost.ScopeExit? It provides same functionality.
The other one I call just RAIIWrapper
[snip] I can't say I like the macro but the general idea looks interesting. I think the reference to base class trick can be used to hide the deleter type. Below is a code snippet (incomplete) illustrating the general idea I have. struct scope_guard_base { scope_guard_base() : active(true) {} bool active; }; template< typename F, typename Base = scope_guard_base > struct scope_guard_impl : Base { ~scope_guard_impl() { if (this->active) m_fun(); } private: F m_fun; }; typedef scope_guard_base const& scope_guard; template< typename F > scope_guard_impl< F > make_scope_guard(F fun) { return scope_guard_impl< F >(fun); } template< typename T > struct raii : scope_guard_base { T const& get() const { return m_obj; } private: T m_obj; }; template< typename T, typename F > scope_guard_impl< F, raii< T > > make_raii(T obj, F fun) { return scope_guard_impl< F, raii< T > >(fun, obj); } int main() { scope_guard guard = make_scope_guard(...); raii< HANDLE > const& handle = make_raii(CreateHandle(...), bind(CloseHandle, _1)); } With a little more work CloseHandle can be specified without bind (i.e. if you detect that the function accepts a single argument of type T).