ola::plugin::usbdmx::ThreadedUsbSender Class Reference

Detailed Description

Send DMX data using libusb, from a separate thread.

The synchronous libusb calls can sometimes take a while to complete, I've seen cases of up to 21ms.

To avoid blocking the main thread, we need to perform the libusb transfer calls in a separate thread. This class contains all the thread management code, leaving the subclass to implement TransmitBuffer(), which performs the actual transfer.

ThreadedUsbSender can be used as a building block for synchronous widgets.

Inheritance diagram for ola::plugin::usbdmx::ThreadedUsbSender:

Collaboration diagram for ola::plugin::usbdmx::ThreadedUsbSender:

Public Member Functions
	ThreadedUsbSender (libusb_device *usb_device, libusb_device_handle *usb_handle, int interface_number=0)
	Create a new ThreadedUsbSender. More...
bool	Start ()
	Start the new thread. More...
void *	Run ()
	Entry point for the new thread. More...
bool	SendDMX (const DmxBuffer &buffer)
	Buffer a DMX frame for sending. More...

Protected Member Functions
virtual bool	TransmitBuffer (libusb_device_handle *handle, const DmxBuffer &buffer)=0
	Perform the DMX transfer. More...

Constructor & Destructor Documentation

ola::plugin::usbdmx::ThreadedUsbSender::ThreadedUsbSender	(	libusb_device *	usb_device,
		libusb_device_handle *	usb_handle,
		int	interface_number = 0
	)

Create a new ThreadedUsbSender.

Parameters

usb_device	The usb_device to use. The ThreadedUsbSender takes a ref on the device, while the ThreadedUsbSender object exists.
usb_handle	The handle to use for the DMX transfer.
interface_number	the USB interface number of the widget. Defaults to 0.

Member Function Documentation

void * ola::plugin::usbdmx::ThreadedUsbSender::Run ( )

virtual

Entry point for the new thread.

Returns

NULL.

Implements ola::thread::Thread.

bool ola::plugin::usbdmx::ThreadedUsbSender::SendDMX

(

const DmxBuffer &

buffer

)

Buffer a DMX frame for sending.

Parameters

buffer

the DmxBuffer to send.

This should be called in the main thread.

bool ola::plugin::usbdmx::ThreadedUsbSender::Start ( )

virtual

Start the new thread.

Returns

true if the thread is running, false otherwise.

Reimplemented from ola::thread::Thread.

virtual bool ola::plugin::usbdmx::ThreadedUsbSender::TransmitBuffer ( libusb_device_handle *  handle, const DmxBuffer &  buffer  )

protectedpure virtual

Perform the DMX transfer.

Parameters

handle	the libusb_device_handle to use for the transfer.
buffer	The DmxBuffer to transfer.

Returns

true if the transfer was completed, false otherwise.

This is called from the sender thread.

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The documentation for this class was generated from the following files:

• plugins/usbdmx/ThreadedUsbSender.h
• plugins/usbdmx/ThreadedUsbSender.cpp