[pclasses-devel] SharedLibDispatcher?

[stephan b. <st...@s1...>]

How about this idea:

Dispatch DLL loads based on the extension of the actual file. Platforms 
which support more than one loader/binary format could use this to load 
different lib formats. Also, client code could subclasses SharedLib to 
provide DLL-like interfaces into non-DLL structures, like XML files or 
app-specific plugin interfaces.

The implementation for this is trivial:

SharedLibDispatcher : public PluginManager<SharedLib>
{
// this class inherits:
//	void registerFactory( const string & extension,
//				SharedLib * (*factory_func)() );
  virtual SharedLib * create(const string &);
 // ^^^ overridden, assuming string is a file name, loads
 // the proper extension handler, and returns that handler
...
// plus convenience funcs for finding DLLs via
// path searching.
};


One implication is that we would need to:

a) change SharedLib to be default constructable (so we can instantiate 
it via a generic factory) and add API to be able to open the lib 
post-ctor. We should do this, anyway.
or
b) refactor the factory support ("refactorying") to somehow support 
passing args to ctors via factories. So far i don't have an idea for 
how to generically pass args to ctors via factories.
or
c) It wouldn't be hard to implement a custom factory interface which 
forces passing one argument to the ctor. In this case we would pass a 
string (the file name):
class Factory<InterfaceT,[ContextT,?]KeyT,Arg1T> {

  void registerFactory( const KeyT & key, InterfaceT * (*fac_func)
(Arg1T) );

  InterfaceT * create( const KeyT & key, Arg1T arg );

...
};


???

-- 
----- st...@s1...   http://s11n.net
"...pleasure is a grace and is not obedient to the commands
of the will." -- Alan W. Watts