Global Interface Tableのラッパー

git_ptr.hpp

/*
git_ptr.hpp: Copyright 2014 Egtra

Boost Software License - Version 1.0 - August 17th, 2003

Permission is hereby granted, free of charge, to any person or organization
obtaining a copy of the software and accompanying documentation covered by
this license (the "Software") to use, reproduce, display, distribute,
execute, and transmit the Software, and to prepare derivative works of the
Software, and to permit third-parties to whom the Software is furnished to
do so, all subject to the following:

The copyright notices in the Software and this entire statement, including
the above license grant, this restriction and the following disclaimer,
must be included in all copies of the Software, in whole or in part, and
all derivative works of the Software, unless such copies or derivative
works are solely in the form of machine-executable object code generated by
a source language processor.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
*/

#include <atomic>
#include <system_error>

#include <utility> // swap
#include <comdef.h>

class git_ptr_base
{
protected:
	static void throw_if_failed(HRESULT hr)
	{
		if (FAILED(hr))
			throw std::system_error(static_cast<int>(hr), std::system_category());
	}

	static IGlobalInterfaceTablePtr get_git()
	{
		IGlobalInterfaceTablePtr ret;
		throw_if_failed(CoCreateInstance(CLSID_StdGlobalInterfaceTable, nullptr, CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&ret)));
		return ret;
	}

	template<typename T>
	static DWORD register_git(T* p)
	{
		if (p == nullptr)
			return 0;
		DWORD ret;
		throw_if_failed(get_git()->RegisterInterfaceInGlobal(p, __uuidof(T), &ret));
		return ret;
	}

	static void revoke_git(DWORD cookie)
	{
		if (cookie == 0)
			return;
		(void)get_git()->RevokeInterfaceFromGlobal(cookie);
	}

	template<typename T>
	static T* get_from_git(DWORD cookie)
	{
		if (cookie == 0)
			return nullptr;
		T* ret;
		throw_if_failed(get_git()->GetInterfaceFromGlobal(cookie, IID_PPV_ARGS(&ret)));
		return ret;
	}

	template<typename Interface>
	struct com_smart_ptr
	{
		_COM_SMARTPTR_TYPEDEF(Interface, __uuidof(Interface));
		typedef InterfacePtr type;
	};
};

template<typename T>
class git_ptr : protected git_ptr_base
{
public:
	git_ptr() throw() : m_cookie() {}
	git_ptr(_In_opt_ T* p) : m_cookie(register_git(p)) {}
	explicit git_ptr(DWORD cookie) throw() : m_cookie(cookie) {}

#if _MSC_VER >= 1600
	git_ptr(git_ptr&& y) throw() : m_cookie(y.release()) {}

	git_ptr& operator=(git_ptr&& y) throw()
	{
		reset(y.release());
		return *this;
	}
#endif

	git_ptr& operator=(_In_opt_ T* p)
	{
		reset(p);
		return *this;
	}

#if _MSC_VER >= 1800
	git_ptr(const git_ptr&) = delete;
	git_ptr& operator=(const git_ptr&) = delete;
#endif

	~git_ptr() { revoke_git(m_cookie); }

	void reset() throw() { revoke_git(release()); }
	void reset(_In_opt_ T* p) { reset(register_git(p)); }
	void reset(DWORD cookie) { git_ptr(cookie).swap(*this); }
	void swap(git_ptr& y) { std::swap(m_cookie, y.m_cookie); }

	DWORD release() throw()
	{
		DWORD ret = m_cookie;
		m_cookie = 0;
		return ret;
	}

#if _MSC_VER >= 1800
	explicit operator bool() const throw() { return m_cookie != 0; }
#endif
	typename com_smart_ptr<T>::type get() const throw() { return get_from_git<T>(m_cookie); }
	DWORD get_cookie() const throw() { return m_cookie; }

private:
	DWORD m_cookie;
};

template<typename T>
class atomic_git_ptr : protected git_ptr_base
{
public:
	atomic_git_ptr() throw() : m_cookie() {}
	atomic_git_ptr(_In_opt_ T* p) : m_cookie(register_git(p)) {}
	explicit atomic_git_ptr(DWORD cookie) throw() : m_cookie(cookie) {}
#if _MSC_VER >= 1600
	atomic_git_ptr(git_ptr<T>&& y) throw() : m_cookie(y.release()) {}

	atomic_git_ptr& operator=(git_ptr<T>&& y) throw()
	{
		reset(y.release());
		return *this;
	}
#endif

	atomic_git_ptr& operator=(_In_opt_ T* p)
	{
		reset(p);
		return *this;
	}

#if _MSC_VER >= 1800
	atomic_git_ptr(atomic_git_ptr&&) = delete;
	atomic_git_ptr(const atomic_git_ptr&) = delete;
	atomic_git_ptr& operator=(atomic_git_ptr&&) = delete;
	atomic_git_ptr& operator=(const atomic_git_ptr&) = delete;
#endif

	~atomic_git_ptr()
	{
		//revoke_git(m_cookie.non_atomic_load());
		revoke_git(m_cookie.load(std::memory_order_relaxed));
	}

	void reset() throw() { revoke_git(release()); }
	void reset(_In_opt_ T* p) { reset(register_git(p)); }
	void reset(DWORD cookie) { revoke_git(m_cookie.exchange(cookie)); }
	
#if _MSC_VER >= 1600
	git_ptr<T> exchange(git_ptr<T>&& desired) throw()
	{
		return git_ptr<T>(m_cookie.exchange(desired.release()));
	}
#endif

	DWORD release() throw() { return m_cookie.exchange(0); }

#if _MSC_VER >= 1800
	explicit operator bool() const throw() { return m_cookie != 0; }
#endif
	typename com_smart_ptr<T>::type get() const throw() { return get_from_git<T>(m_cookie); }
	DWORD get_cookie() const throw() { return m_cookie; }
	bool is_lock_free() const throw() { return m_cookie.is_lock_free(); }

private:
	std::atomic<DWORD> m_cookie;
};

template<typename T>
git_ptr<T> make_git(_In_ T* p)
{
	return git_ptr<T>(p);
}