tempname_if_on_network.m

function temp_fn = tempname_if_on_network(fn)
    persistent isNetworkDrive isNetworkDriveBackup
    
%     temp_fn=[];
%     return;
%     
    
    switch(fn)
        case 'on'
            isNetworkDrive=isNetworkDriveBackup;
        case 'off'
            isNetworkDrive = false;
        otherwise 
            if(islogical(isNetworkDrive)&&~isNetworkDrive)
                temp_fn=[];
                return;
            end
            temp_fn = '';
            if(isunix && ~ismac)
                temp_fn = tempname('/dev/shm/');
            elseif(ispc)
                if(isempty(isNetworkDrive))
                    isNetworkDrive = containers.Map('KeyType','char','ValueType','logical');
                    drives = java.io.File('').listRoots();
                    for i=1:numel(drives)
                        isNetworkDrive(char(drives(i))) = ...
                           strcmp('Network Drive',char(javax.swing.filechooser.FileSystemView.getFileSystemView().getSystemTypeDescription(drives(i)))); 
                    end
                    isNetworkDriveBackup=isNetworkDrive;
                end
                ffn = upper(char(java.io.File(fn).getAbsoluteFile()));
                if(length(ffn)>2 && (strcmp(ffn(1:2),'\\') || isNetworkDrive.isKey(ffn(1:3)) && isNetworkDrive(ffn(1:3))))
                    temp_fn = tempname;
                end
            end
    end
end