The Mini Shell Extension Framework – Part III

//
// (C) Copyright by Victor Derks <vba64@xs4all.nl>
//
// See README.TXT for the details of the software licence.
//
#pragma once


#include <shobjidl.h>
#include "olestring.h"


// Visual C++ doesn't like exception handlers that are optimized away in release mode.
#ifdef NDEBUG
#pragma warning(push)
#pragma warning(disable: 4702) // disable unreachable code
#endif


namespace MSF
{

class IItemNameLimitsImplDefault
{
public:
	// Purpose: Override this function to control which chars are valid.
	static const TCHAR* GetValidChars()
	{
		return NULL;
	}


	// Purpose: Override this function to control which chars are invalid.
	static const TCHAR* GetInvalidChars()
	{
		return NULL;
	}
};

template <typename T, typename TItem,
          typename TItemV = IItemNameLimitsImplDefault, typename TItemI = IItemNameLimitsImplDefault>
class ATL_NO_VTABLE IItemNameLimitsImpl :
	public IItemNameLimits
{
public:
	// IItemNameLimits
	STDMETHOD(GetValidCharacters)(LPWSTR* ppwszValidChars, LPWSTR* ppwszInvalidChars)
	{
		try
		{
			ATLTRACE2(atlTraceCOM, 0, _T("IItemNameLimitsImpl::GetValidCharacters\n"));

			const TCHAR* pszValidChars = TItemV::GetValidChars();
			if (pszValidChars == NULL)
			{
				*ppwszValidChars = NULL;

				const TCHAR* pszInvalidChars = TItemI::GetInvalidChars();
				if (pszInvalidChars == NULL)
				{
					*ppwszInvalidChars = NULL;
				}
				else
				{
					*ppwszInvalidChars = COleString::Dup(pszInvalidChars);
				}
			}
			else
			{
				*ppwszValidChars   = COleString::Dup(pszValidChars);
				*ppwszInvalidChars = NULL;
			}
			return S_OK;
		}
		MSF_COM_CATCH_HANDLER()
	}


	// Purpose: called by the shell to retrieve the max length.
	//          Lenght can depend on the current string. (UNC pathname has
	//          different length then local path, etc).
	//
	STDMETHOD(GetMaxLength)(LPCWSTR pszName, int* piMaxNameLen)
	{
		try
		{
			ATLTRACE2(atlTraceCOM, 0, _T("IItemNameLimitsImpl::GetMaxLength, name=%s\n"), pszName);

			// The TItem must implement the static function GetMaxItemNameLength.
			*piMaxNameLen = TItem::GetMaxNameLength(pszName);

			ATLASSERT(*piMaxNameLen >= 0 && "negative length?");
			return S_OK;
		}
		MSF_COM_CATCH_HANDLER()
	}
 };

} // namespace MSF