AICommon::PollLoop Class Reference

A wrapper around epoll that allows for adding, modifying & deleting of source events. More...

#include <PollLoop.h>

Inheritance diagram for AICommon::PollLoop:

Collaboration diagram for AICommon::PollLoop:

Classes
struct	tagPollSourceWrapper

Public Member Functions
	PollLoop (const std::string &name, int maxSources=512, long deferredTimeInterval=20)
	Constructs a poll loop with the given name and restrictions. More...
virtual	~PollLoop ()
	Destructs the poll loop, tears down the thread if the loop is running.
virtual bool	start (int priority=-1) override
	Starts the poll thread. More...
virtual void	stop () override
	Stops the poll loop thread. More...
virtual bool	addSource (const std::shared_ptr< IPollSource > &source, int fd, uint32_t events) override
	Adds a new event source to the poll loop. More...
virtual bool	modSource (const std::shared_ptr< IPollSource > &source, uint32_t events) override
virtual void	delSource (const std::shared_ptr< IPollSource > &source, int fd=-1) override
virtual bool	hasSource (const std::shared_ptr< IPollSource > &source) override
	Returns true if the specified source is currently installed in the pollLoop. More...
virtual std::thread::id	threadId () const override
	Returns the thread id of the poll loop thread. More...
virtual pid_t	gettid () const override
	Returns the linux thread id of the poll loop thread. More...

Private Types
typedef struct AICommon::PollLoop::tagPollSourceWrapper	PollSourceWrapper

Private Member Functions
void	init ()
void	run (const std::string &name, int priority)
	The poll loop thread function. More...
void	enableDeferredTimer ()
	Enables the deferred timer event source. More...
void	disableDeferredTimer ()
	Disables the deferred timer event source.

Private Attributes
const std::string	mName
std::thread	mEPollThread
std::atomic< pid_t >	mEPollThreadId
int	mEPollFd
int	mDeathEventFd
int	mDeferTimerFd
const struct itimerspec	mDeferTimerSpec
Spinlock	mLock
const int	mMaxSources
int	mDeferredSources
std::list< PollSourceWrapper >	mSources

Detailed Description

A wrapper around epoll that allows for adding, modifying & deleting of source events.

Poll loop sources are a tuple of a shared_ptr<IPollSource>, an fd and a bitmask of events to listen on. PollSource objects are store as weak_ptrs and only locked when they have been triggered and their process() function is to be called.

This should make the race conditions with calling an object that has been destroy safe, however it does means that PollSource objects shouldn't assume that their process() methods won't be called after they've been removed from the poll loop.

Constructor & Destructor Documentation

PollLoop()

PollLoop::PollLoop	(	const std::string &	name,
		int	maxSources = 512,
		long	deferredTimeInterval = 20
	)

Constructs a poll loop with the given name and restrictions.

A constructed poll loop is not automatically started, rather the caller should call start to spawn a thread and run the poll loop inside it.

Parameters

[in]	name	The name to give the poll loop thread (nb: thread names are limited to 16 characters).
[in]	maxSources	The maximum number of event sources that can be installed on the poll loop.
[in]	deferredTimeInterval	The time interval in milliseconds of the deferred timer

Member Function Documentation

addSource()

bool PollLoop::addSource ( const std::shared_ptr< IPollSource > &  source, int  fd, uint32_t  events  )

overridevirtual

Adds a new event source to the poll loop.

A source is a file descriptor, a bitmask of events to wait for and a IPollSource object that will be called when any of the events in the bitmask occur on the file descriptor.

This method may fail if the number of sources installed exceeds the maximum allowed.

Parameters

[in]	source	The source object to call process() on when an event occurs
[in]	fd	The file descriptor to poll on
[in]	events	A bitmask of events to listen on

Returns

true on success, false on failure.

Implements AICommon::IPollLoop.

enableDeferredTimer()

void PollLoop::enableDeferredTimer ( )

inlineprivate

Enables the deferred timer event source.

This is an internal function that is called when a source event has been 'deferred', i.e. a client has called modSource(..., EPOLLDEFERRED).

gettid()

pid_t PollLoop::gettid ( ) const

overridevirtual

Returns the linux thread id of the poll loop thread.

If the poll loop /threa is not current running -1 will be returned.

Implements AICommon::IPollLoop.

hasSource()

bool PollLoop::hasSource ( const std::shared_ptr< IPollSource > &  source )

overridevirtual

Returns true if the specified source is currently installed in the pollLoop.

Parameters

[in]

source

The source object to search for in the pollLoop

Returns

True if source installed

Implements AICommon::IPollLoop.

run()

void PollLoop::run ( const std::string &  name, int  priority  )

private

The poll loop thread function.

This is the thread that does all the epoll stuff.

start()

bool PollLoop::start ( int  priority = -1 )

overridevirtual

Starts the poll thread.

If the poll loop was already running it is stopped and restarted.

Parameters

[in]

priority

The SCRED_RR priority in which to run the poll loop, if -1 the priority is inherited from the calling thread

Returns

true on success, false on failure.

Implements AICommon::IPollLoop.

stop()

void PollLoop::stop ( )

overridevirtual

Stops the poll loop thread.

Stops the poll loop and cleans up all the resources associated with it.

Implements AICommon::IPollLoop.

threadId()

std::thread::id PollLoop::threadId ( ) const

overridevirtual

Returns the thread id of the poll loop thread.

If the poll loop /threa is not current running, a default constructed std::thread::id is returned.

Implements AICommon::IPollLoop.

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

• AppInfrastructure/Common/include/PollLoop.h
• AppInfrastructure/Common/source/PollLoop.cpp