ola::plugin::usbdmx::ThreadedUsbReceiver Class Reference

Detailed Description

Receive 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 ReceiveBuffer(), which performs the actual transfer.

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

Inheritance diagram for ola::plugin::usbdmx::ThreadedUsbReceiver:

Collaboration diagram for ola::plugin::usbdmx::ThreadedUsbReceiver:

Public Member Functions
	ThreadedUsbReceiver (libusb_device *usb_device, libusb_device_handle *usb_handle, PluginAdaptor *plugin_adaptor, int interface_number=0)
	Create a new ThreadedUsbReceiver. More...
bool	Start ()
	Start the new thread. More...
void *	Run ()
	Entry point for the new thread. More...
void	SetReceiveCallback (Callback0< void > *callback)
	Set the callback to be called when the receive buffer is updated. More...
const DmxBuffer &	GetDmxInBuffer () const
	Get DMX Buffer. More...

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

Constructor & Destructor Documentation

ThreadedUsbReceiver()

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

Create a new ThreadedUsbReceiver.

Parameters

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

Member Function Documentation

GetDmxInBuffer()

const DmxBuffer& ola::plugin::usbdmx::ThreadedUsbReceiver::GetDmxInBuffer ( ) const

inline

Get DMX Buffer.

Returns

DmxBuffer with current input values.

ReceiveBuffer()

virtual bool ola::plugin::usbdmx::ThreadedUsbReceiver::ReceiveBuffer ( libusb_device_handle *  handle, DmxBuffer *  buffer, bool *  buffer_updated  )

protectedpure virtual

Perform the DMX transfer.

Parameters

handle	the libusb_device_handle to use for the transfer.
buffer	The DmxBuffer to be updated.
buffer_updated	set to true when buffer was updated (=data received)

Returns

true if the transfer was completed, false otherwise.

This is called from the receiver thread.

Run()

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

virtual

Entry point for the new thread.

Returns

NULL.

Implements ola::thread::Thread.

SetReceiveCallback()

void ola::plugin::usbdmx::ThreadedUsbReceiver::SetReceiveCallback ( Callback0< void > *  callback )

inline

Set the callback to be called when the receive buffer is updated.

Parameters

callback

The callback to call.

Start()

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

virtual

Start the new thread.

Returns

true if the thread is running, false otherwise.

Reimplemented from ola::thread::Thread.

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

• plugins/usbdmx/ThreadedUsbReceiver.h
• plugins/usbdmx/ThreadedUsbReceiver.cpp