Refactor rdpdr client

[ibeckermayer]

This is primarily a refactor. Before, all the logic for handling each major function was in the match statement in handle_device_io_request, now the relevant bit of code looks like

        match major_function {
            MajorFunction::IRP_MJ_DEVICE_CONTROL => {
                self.process_irp_device_control(device_io_request, payload)
            }
            MajorFunction::IRP_MJ_CREATE => self.process_irp_create(device_io_request, payload),
            MajorFunction::IRP_MJ_QUERY_INFORMATION => {
                self.process_irp_query_information(device_io_request, payload)
            }
            MajorFunction::IRP_MJ_CLOSE => self.process_irp_close(device_io_request),
            _ => Err(invalid_data_error(&format!(
                // TODO(isaiah): send back a not implemented response(?)
                "got unsupported major_function in DeviceIoRequest: {:?}",
                &major_function
            ))),
        }

with the bulk of the logic copied into the process_irp_*'s. Also adds some more consistent debugging logging.

[zmb3]

Approving as all of my comments are stylistic, but I hope you'll address them 😄

[zmb3]

What error is this checking?

[zmb3]

What to these x --> y comments mean?

[ibeckermayer]

The line above them points to the corollary code in FreeRDP where x is set (as a FreeRDP-type error), and the line itself points to the code in RDP where x is converted to y, the actual RDP code that's sent by FreeRDP. Its basically documenting how I determined which NTSTATUS to send back. Probably unnecessary to leave in, deleted.

[zmb3]

I tend to prefer match over a large if/else chain