ola::usb::LibUsbThread Class Reference

Detailed Description

The base class for the dedicated libusb thread.

Asynchronous I/O for libusb requires either i) a dedicated thread ii) integration with the i/o event loop. From the libusb documentation, i) has the advantage that it works on Windows, so we do that.

However, there is no easy way to interrupt libusb_handle_events(). Instead we use either libusb_close (for the non-hotplug case) or libusb_hotplug_deregister_callback() (for the hotplug case) to wake libusb_handle_events().

Both these techniques have require care to avoid deadlocks / race conditions. For the non-hotplug case, it's imperative that libusb_open() and libusb_close() are paired with calls to OpenHandle() and CloseHandle().

http://libusb.sourceforge.net/api-1.0/group__asyncio.html covers both approaches.

Inheritance diagram for ola::usb::LibUsbThread:

Collaboration diagram for ola::usb::LibUsbThread:

Public Member Functions
	LibUsbThread (libusb_context *context)
	Base constructor. More...
virtual	~LibUsbThread ()
	Destructor.
virtual bool	Init ()
	Initialize the thread.
virtual void	Shutdown ()
	Shutdown the thread.
void *	Run ()
	The entry point to the libusb thread. More...
virtual void	OpenHandle ()=0
	This must be called whenever libusb_open() is called.
virtual void	CloseHandle (libusb_device_handle *handle)=0
	This must be called whenever libusb_close() is called.

Protected Member Functions
void	SetTerminate ()
	Indicate that the libusb thread should terminate. More...
void	LaunchThread ()
	Start the libusb thread.
void	JoinThread ()
	Join the libusb thread.
libusb_context *	Context () const
	Return the libusb_context this thread uses. More...

Constructor & Destructor Documentation

LibUsbThread()

ola::usb::LibUsbThread::LibUsbThread ( libusb_context *  context )

inlineexplicit

Base constructor.

Parameters

context

the libusb context to use.

Member Function Documentation

Context()

libusb_context* ola::usb::LibUsbThread::Context ( ) const

inlineprotected

Return the libusb_context this thread uses.

Returns

A libusb_context.

Run()

void * ola::usb::LibUsbThread::Run ( )

virtual

The entry point to the libusb thread.

Don't call this directly. It's executed when the thread starts.

Implements ola::thread::Thread.

SetTerminate()

void ola::usb::LibUsbThread::SetTerminate ( )

inlineprotected

Indicate that the libusb thread should terminate.

This doesn't wake up libusb_handle_events(), it simply sets m_term to true.

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

• libs/usb/LibUsbThread.h
• libs/usb/LibUsbThread.cpp