NNet::TUring Class Reference

Poller implementation based on io_uring. More...

#include <uring.hpp>

Inheritance diagram for NNet::TUring:

Public Types
using	TSocket = NNet::TPollerDrivenSocket<TUring>
	Alias for the poller-driven socket type.
using	TFileHandle = NNet::TPollerDrivenFileHandle<TUring>
	Alias for the poller-driven file handle type.

Public Member Functions
	TUring (int queueSize=256)
	Constructs a TUring instance.
	~TUring ()
	Destructor cleans up the io_uring and related resources.
void	Read (int fd, void *buf, int size, std::coroutine_handle<> handle)
	Posts an asynchronous read operation.
void	Write (int fd, const void *buf, int size, std::coroutine_handle<> handle)
	Posts an asynchronous write operation.
void	Recv (int fd, void *buf, int size, std::coroutine_handle<> handle)
	Posts an asynchronous receive operation.
void	Send (int fd, const void *buf, int size, std::coroutine_handle<> handle)
	Posts an asynchronous send operation.
void	Accept (int fd, struct sockaddr *addr, socklen_t *len, std::coroutine_handle<> handle)
	Posts an asynchronous accept operation.
void	Connect (int fd, const sockaddr *addr, socklen_t len, std::coroutine_handle<> handle)
	Posts an asynchronous connect operation.
void	Cancel (int fd)
	Cancels pending operations on the specified file descriptor.
void	Cancel (std::coroutine_handle<> h)
	Cancels pending operations associated with a specific coroutine handle.
void	Register (int fd)
	Registers a file descriptor with the IO_uring poller.
int	Wait (timespec ts={10, 0})
	Waits for I/O completions.
void	Poll ()
	Polls for I/O completions.
int	Result ()
	Retrieves the result of the last completed I/O completion.
void	Submit ()
	Submits queued I/O requests to the kernel.
std::tuple< int, int, int >	Kernel () const
	For testing: retrieves kernel version.
const std::string &	KernelStr () const
	For testing: retrieves a string describing kernel.
Public Member Functions inherited from NNet::TPollerBase
	TPollerBase ()=default
	Default constructor.
	TPollerBase (const TPollerBase &)=delete
	Copying is disabled.
TPollerBase &	operator= (const TPollerBase &)=delete
unsigned	AddTimer (TTime deadline, THandle h)
	Schedules a timer.
bool	RemoveTimer (unsigned timerId, TTime deadline)
	Removes or cancels a timer.
void	AddRead (int fd, THandle h)
	Registers a read event on a file descriptor.
void	AddWrite (int fd, THandle h)
	Registers a write event on a file descriptor.
void	AddRemoteHup (int fd, THandle h)
	Registers a remote hang-up (RHUP) event.
void	RemoveEvent (int fd)
	Removes registered events for a specific file descriptor.
void	RemoveEvent (THandle)
	Removes events associated with a given coroutine handle.
auto	Sleep (TTime until)
	Suspends execution until the specified time.
template<typename Rep, typename Period>
auto	Sleep (std::chrono::duration< Rep, Period > duration)
	Overload of Sleep() accepting a duration.
auto	Yield ()
	Yields execution to the next event loop iteration.
void	Wakeup (TEvent &&change)
	Wakes up a coroutine waiting on an event.
void	WakeupReadyHandles ()
	Wakes up all coroutines waiting on ready events.
void	SetMaxDuration (std::chrono::milliseconds maxDuration)
	Sets the maximum polling duration.
auto	TimersSize () const
	Returns the number of scheduled timers.

Additional Inherited Members
Protected Member Functions inherited from NNet::TPollerBase
timespec	GetTimeout () const
	Computes the poll timeout based on scheduled timers.
void	Reset ()
	Clears the lists of ready events and pending changes.
void	ProcessTimers ()
	Processes scheduled timers.
Static Protected Member Functions inherited from NNet::TPollerBase
static constexpr timespec	GetMaxDuration (std::chrono::milliseconds duration)
	Computes a timespec from a duration.
Protected Attributes inherited from NNet::TPollerBase
int	MaxFd_ = -1
	Highest file descriptor in use.
std::vector< TEvent >	Changes_
	Pending changes (registered events).
std::vector< TEvent >	ReadyEvents_
	Events ready to wake up their coroutines.
unsigned	TimerId_ = 0
	Counter for generating unique timer IDs.
std::priority_queue< TTimer >	Timers_
	Priority queue for scheduled timers.
TTime	LastTimersProcessTime_
	Last time timers were processed.
unsigned	LastFiredTimer_ = (unsigned)(-1)
	ID of the last fired timer.
std::chrono::milliseconds	MaxDuration_ = std::chrono::milliseconds(100)
	Maximum poll duration.
timespec	MaxDurationTs_ = GetMaxDuration(MaxDuration_)
	Max duration represented as timespec.

Detailed Description

Poller implementation based on io_uring.

TUring inherits from TPollerBase and implements asynchronous I/O operations using the Linux io_uring API. It provides methods for performing asynchronous read, write, receive, send, accept, and connect operations.

Key features:

• Uses io_uring to queue and submit asynchronous I/O operations.
• Provides operations such as Read(), Write(), Recv(), Send(), Accept() and Connect().
• Offers additional methods for cancelling pending operations, registering file descriptors, waiting for completions, and submitting queued requests.

Type aliases:

• TSocket is defined as NNet::TPollerDrivenSocket<TUring>.
• TFileHandle is defined as NNet::TPollerDrivenFileHandle<TUring>.

Example usage:

// Create an io_uring poller with a queue size of 256.
TUring uringPoller(256);
 
// Register a socket or file descriptor.
uringPoller.Register(socketFd);
 
// Post an asynchronous read.
uringPoller.Read(socketFd, buffer, bufferSize, coroutineHandle);
 
// Submit queued operations.
uringPoller.Submit();
 
// Poll for I/O completions.
int ret = uringPoller.Wait();
 
// Process the result of the completed operations.
int result = uringPoller.Result();

Additional methods for testing:

• Kernel() returns a tuple of kernel-provided statistics.
• KernelStr() returns a descriptive string with kernel statistics.

Constructor & Destructor Documentation

TUring()

NNet::TUring::TUring

(

int

queueSize = 256

)

Constructs a TUring instance.

Parameters

queueSize

The desired size of the io_uring submission queue (default is 256).

Member Function Documentation

Accept()

void NNet::TUring::Accept	(	int	fd,
		struct sockaddr *	addr,
		socklen_t *	len,
		std::coroutine_handle<>	handle )

Posts an asynchronous accept operation.

Parameters

fd	The listening socket descriptor.
addr	Pointer to a sockaddr structure where the client address is stored.
len	Pointer to the length of the address structure.
handle	Coroutine handle to resume upon acceptance.

Cancel() [1/2]

void NNet::TUring::Cancel

(

int

fd

)

Cancels pending operations on the specified file descriptor.

Parameters

fd	The file descriptor.

Cancel() [2/2]

void NNet::TUring::Cancel

(

std::coroutine_handle<>

h

)

Cancels pending operations associated with a specific coroutine handle.

Parameters

h	The coroutine handle.

Connect()

void NNet::TUring::Connect	(	int	fd,
		const sockaddr *	addr,
		socklen_t	len,
		std::coroutine_handle<>	handle )

Posts an asynchronous connect operation.

Parameters

fd	The socket descriptor.
addr	Pointer to the destination address.
len	Size of the destination address structure.
handle	Coroutine handle to resume upon connection.

Kernel()

std::tuple< int, int, int > NNet::TUring::Kernel

(

)

const

For testing: retrieves kernel version.

Returns

A tuple of integers representing kernel version.

KernelStr()

const std::string & NNet::TUring::KernelStr

(

)

const

For testing: retrieves a string describing kernel.

Returns

A descriptive string with kernel version.

Poll()

void NNet::TUring::Poll ( )

inline

Polls for I/O completions.

This method simply calls Wait() with a computed timeout.

Read()

void NNet::TUring::Read	(	int	fd,
		void *	buf,
		int	size,
		std::coroutine_handle<>	handle )

Posts an asynchronous read operation.

Parameters

fd	The file descriptor.
buf	Buffer where data is to be stored.
size	Number of bytes to read.
handle	Coroutine handle to resume upon completion.

Recv()

void NNet::TUring::Recv	(	int	fd,
		void *	buf,
		int	size,
		std::coroutine_handle<>	handle )

Posts an asynchronous receive operation.

Parameters

fd	The file descriptor.
buf	Buffer where received data will be stored.
size	Maximum number of bytes to receive.
handle	Coroutine handle to resume upon completion.

Register()

void NNet::TUring::Register

(

int

fd

)

Registers a file descriptor with the IO_uring poller.

Parameters

fd	The file descriptor to register.

Result()

int NNet::TUring::Result

(

)

Retrieves the result of the last completed I/O completion.

Returns

An integer result, such as the number of bytes transferred.

Send()

void NNet::TUring::Send	(	int	fd,
		const void *	buf,
		int	size,
		std::coroutine_handle<>	handle )

Posts an asynchronous send operation.

Parameters

fd	The file descriptor.
buf	Buffer containing data to send.
size	Number of bytes to send.
handle	Coroutine handle to resume upon completion.

Wait()

int NNet::TUring::Wait

(

timespec

ts = {10, 0}

)

Waits for I/O completions.

Parameters

ts	Optional timeout (default is 10 seconds, expressed as {10, 0}).

Returns

The number of completed events (or a negative value on error).

Write()

void NNet::TUring::Write	(	int	fd,
		const void *	buf,
		int	size,
		std::coroutine_handle<>	handle )

Posts an asynchronous write operation.

Parameters

fd	The file descriptor.
buf	Buffer with data to write.
size	Number of bytes to write.
handle	Coroutine handle to resume upon completion.

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

• coroio/uring.hpp