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:

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

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

Additional Inherited Members
Private Member Functions inherited from ola::thread::Thread
	Thread (const Options &options=Options())
	Create a new thread with the specified thread options.
virtual	~Thread ()
	Destructor.
virtual bool	Start ()
	Start the thread and wait for the thread to be running.
virtual bool	FastStart ()
	Start the thread and return immediately.
virtual bool	Join (void *ptr=NULL)
	Join this thread.
bool	IsRunning ()
	Check if the thread is running.
ThreadId	Id () const
	Return the thread id.
std::string	Name () const
	Return the thread name.
virtual void *	Run ()=0
	The entry point for the new thread.
Static Private Member Functions inherited from ola::thread::Thread
static ThreadId	Self ()
	Returns the current thread's id.

Constructor & Destructor Documentation

ola::plugin::usbdmx::ThreadedUsbSender::ThreadedUsbSender	(	libusb_device *	usb_device,
		libusb_device_handle *	usb_handle
	)

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.

Member Function Documentation

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

(

)

Entry point for the new thread.

Returns

NULL.

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

(

)

Start the new thread.

Returns

true if the thread is running, false otherwise.

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.

---

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

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