eudora-mac/Include/MachOWrapper.h

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/*
	A template class that holds a pointer to a Mach-O framework entry point.

Author: Marshall Clow

Change Log:
		13-Aug-2002		mc			Initial Version
		
*/

#ifndef	__MACHOWRAPPER__
#define	__MACHOWRAPPER__

#include <MacTypes.h>
#include <CFBundle.h>

#if !TARGET_RT_MAC_CFM
#error	"This code only works for CFM Targets!"
#endif

OSStatus LoadFrameworkBundle ( CFStringRef framework, CFBundleRef *bundlePtr );

template <typename Proc>
class MachOWrapper {
private:
	CFBundleRef 	fBundle;		//	The reference to the framework pointer
	Proc			fProcPtr;		//	The actual procedure pointer

public:
	MachOWrapper ( CFStringRef framework, CFStringRef routine ) : fBundle ( NULL ), fProcPtr ( NULL ) {
	//	Get the framework bundle
		OSStatus err = ::LoadFrameworkBundle ( framework, &fBundle );
	//	Don't call "CFBundleGetFunctionPointerForName" with an invalid bundle - it will crash.
		if ( err != noErr )
			fBundle = NULL;
		else {
			fProcPtr = (Proc) CFBundleGetFunctionPointerForName ( fBundle, routine );
			if ( fProcPtr == nil )
				err = cfragNoSymbolErr;
			}
	//	Have to throw something if we don't link up!
		}

	MachOWrapper ( CFBundleRef 	aBundle, CFStringRef routine ) : fBundle ( aBundle ), fProcPtr ( NULL ) {
		OSStatus err = noErr;
		CFRetain ( fBundle );
		fProcPtr = (Proc) CFBundleGetFunctionPointerForName ( fBundle, routine );
		if ( fProcPtr == nil )
			err = cfragNoSymbolErr;
	//	Have to throw something if we don't link up!
		}

	~MachOWrapper () { if ( fBundle != NULL ) CFRelease ( fBundle ); }

	Boolean IsValid () const { return fProcPtr != NULL; }
	
//	Marshall dreams:
//	A whole set of templates for different numbers of arguments
//	The beauty of this is that only one will be instantiated by the compiler
//	for each specialization of this template.

#if 0
	template <typename R>
	R operator () () const
		{ return fProcPtr (); }
	
	template <typename R, typename A1>
	R operator () (A1 arg1) const
		{ return fProcPtr (arg1); }

	template <typename R, typename A1, typename A2>
	R operator () (A1 arg1, A2 arg2) const
		{ return fProcPtr (arg1, arg2); }

	template <typename R, typename A1, typename A2, typename A3>
	R operator () (A1 arg1, A2 arg2, A3 arg3) const
		{ return fProcPtr (arg1, arg2, arg3); }

	template <typename R, typename A1, typename A2, typename A3, typename A4>
	R operator () (A1 arg1, A2 arg2, A3 arg3, A4 arg4) const
		{ return fProcPtr (arg1, arg2, arg3, arg4); }

	template