MStatus ParameterisedHolder<B>::createOrUpdateAttribute( IECore::ParameterPtr parameter, const MString &attributeName, bool callRestore )
{
MObject node = B::thisMObject();
MFnDependencyNode fnDN( node );
MPlugArray connectionsFromMe, connectionsToMe;
// try to reuse an old plug if we can
MPlug plug = fnDN.findPlug( attributeName, false /* no networked plugs please */ );
if( !plug.isNull() )
{
MStatus s = MS::kSuccess;
if( callRestore )
{
ParameterHandler::restore( plug, parameter );
}
if( s )
{
s = IECoreMaya::ParameterHandler::update( parameter, plug );
if( s )
{
return MS::kSuccess;
}
}
// failed to restore and/or update (parameter type probably changed).
// remove the current attribute and fall through to the create
// code
// remember connections so we can remake them for the new
// attribute. we have to be careful to only store non-networked plugs as
// networked plugs are invalidated by the removal of the attribute.
nonNetworkedConnections( plug, connectionsFromMe, connectionsToMe );
fnDN.removeAttribute( plug.attribute() );
}
// reuse failed - create a new attribute
/// \todo: update ParameterisedHolder to accept null plugs when the todo in ParameterHandler::create is addressed
plug = IECoreMaya::ParameterHandler::create( parameter, attributeName, node );
if( plug.isNull() )
{
msg( Msg::Error, "ParameterisedHolder::createOrUpdateAttribute", boost::format( "Failed to create attribute to represent parameter \"%s\" of type \"%s\"" ) % parameter->name() % parameter->typeName() );
return MS::kFailure;
}
// restore any existing connections
if( connectionsFromMe.length() || connectionsToMe.length() )
{
MDGModifier dgMod;
for (unsigned i = 0; i < connectionsFromMe.length(); i++)
{
dgMod.connect( plug, connectionsFromMe[i] );
}
for (unsigned i = 0; i < connectionsToMe.length(); i++)
{
dgMod.connect( connectionsToMe[i], plug );
}
dgMod.doIt();
}
/// and set the value of the attribute, in case it differs from the default
return IECoreMaya::ParameterHandler::setValue( parameter, plug );
}
