Structure to poll for a set of file descriptors and timeouts. More...

#include <pollset.h>

Inheritance diagram for xdr::pollset:

Classes
class	Timeout
	Abstract class used to represent a pending timeout. More...

Public Types
enum	op_t { Read = kReadFlag, Write = kWriteFlag, ReadWrite = kReadFlag \| kWriteFlag, ReadOnce = kReadFlag \| kOnceFlag, WriteOnce = kWriteFlag \| kOnceFlag }

using	cb_t = std::function< void()>

Public Member Functions
	pollset (const pollset &)=delete

void	poll (int timeout=-1)
	Go through one round of checking all file descriptors. More...

virtual bool	pending () const
	Returns `false` if no file descriptor callbacks are registered and no timeouts or asynchronous events are pending. More...

void	run ()
	Continously poll and only return on exception or when there is no more work to do. More...

template<typename CB >
void	fd_cb (sock_t s, op_t op, CB &&cb)
	Set a read or write callback on a particular file descriptor. More...

void	fd_cb (sock_t s, op_t op, std::nullptr_t=nullptr)
	Remove a callback on a file descriptor. More...

template<typename CB >
Timeout	timeout (std::int64_t ms, CB &&cb)
	Set a callback to run a certain number of milliseconds from now. More...

template<typename CB >
Timeout	timeout_at (std::int64_t ms, CB &&cb)
	Set a callback to run at a specific time (as returned by PollSet::now_ms()). More...

void	timeout_cancel (Timeout &t)
	Cancel a pending timeout. More...

std::int64_t	timeout_time (Timeout t) const
	Returns the absolute time (in milliseconds) at which a timeout will run. More...

void	timeout_reschedule_at (Timeout &t, std::int64_t ms)
	Reschedule a timeout to run at a specific time. More...

void	timeout_reschedule (Timeout &t, std::int64_t ms)
	Reschedule a timeout some number of milliseconds in the future.

Static Public Member Functions
static std::int64_t	now_ms ()
	Number of milliseconds since an arbitrary but fixed time, used as the basis of all timeouts. More...

static Timeout	timeout_null ()
	An invalid timeout, useful for initializing PollSet::Timeout values before a timeout has been scheduled. More...

Protected Member Functions
std::size_t	num_cbs () const
	Number of registered file decriptor and timeout callbacks.

Static Protected Attributes
static constexpr int	kReadFlag = 0x1

static constexpr int	kWriteFlag = 0x2

static constexpr int	kOnceFlag = 0x4

Detailed Description

Structure to poll for a set of file descriptors and timeouts.

Definition at line 23 of file pollset.h.

Member Enumeration Documentation

◆ op_t

enum xdr::pollset::op_t

Enumerator
Read	Specify interest in read-ready condition.
Write	Specify interest in write-ready condition.
ReadWrite	Valid only when removing callbacks.
ReadOnce	Like `Read`, but the callback only executes once.
WriteOnce	Like `Write`, but the callback only executes once.

Definition at line 32 of file pollset.h.

Member Function Documentation

◆ poll()

void xdr::pollset::poll ( int timeout = -1 )

Go through one round of checking all file descriptors.

timeout is a timeout in milliseconds (or -1 to wait forever).

Typical usage:

PollSet ps;
// ... register some callbacks or asynchronous events ...
while(ps.pending())
  ps.poll();

Definition at line 217 of file pollset.cc.

◆ pending()

virtual bool xdr::pollset::pending ( ) const

inlinevirtual

Returns false if no file descriptor callbacks are registered and no timeouts or asynchronous events are pending.

If it returns false, then PollSet::poll will pause forever in the absence of a signal or a call to PollSet::inject_cb in a different thread.

Reimplemented in xdr::pollset_plus.

Definition at line 93 of file pollset.h.

◆ run()

void xdr::pollset::run ( )

inline

Continously poll and only return on exception or when there is no more work to do.

Definition at line 97 of file pollset.h.

◆ fd_cb() [1/2]

template<typename CB >

void xdr::pollset::fd_cb	(	sock_t	s,
		op_t	op,
		CB &&	cb
	)

inline

Set a read or write callback on a particular file descriptor.

fd is the file descriptor.
op specifies the condition on which to invoke the callback. Only one Read and one Write callback are permitted per file descriptor. E.g., calling set_cb with ReadOnce overwrites a previous Read callback on the same file descriptor. The value ReadWrite is illegal when adding a callback (you must set Read and Write callbacks separately).
cb is the callback, which must be convertible to PollSet::cb_t.

Definition at line 108 of file pollset.h.

◆ fd_cb() [2/2]

void xdr::pollset::fd_cb	(	sock_t	s,
		op_t	op,
		std::nullptr_t	= `nullptr`
	)

Remove a callback on a file descriptor.

If op is ReadWrite, removes both read and write callbacks on the descriptor.

Definition at line 170 of file pollset.cc.

◆ now_ms()

std::int64_t xdr::pollset::now_ms ( )

static

Number of milliseconds since an arbitrary but fixed time, used as the basis of all timeouts.

Time zero is std::chrono::steady_clock's epoch, which in some implementations is the time a machine was booted.

Definition at line 409 of file pollset.cc.

◆ timeout()

template<typename CB >

Timeout xdr::pollset::timeout	(	std::int64_t	ms,
		CB &&	cb
	)

inline

Set a callback to run a certain number of milliseconds from now.

ms is the delay in milliseconds before running the callback.
cb must be convertible to PollSet::cb_t.
Returns
an object on which you can call the method PollSet::timeout_cancel to cancel the timeout.

Definition at line 148 of file pollset.h.

◆ timeout_at()

template<typename CB >

Timeout xdr::pollset::timeout_at	(	std::int64_t	ms,
		CB &&	cb
	)

inline

Set a callback to run at a specific time (as returned by PollSet::now_ms()).

Definition at line 153 of file pollset.h.

◆ timeout_null()

pollset::Timeout xdr::pollset::timeout_null ( )

static

An invalid timeout, useful for initializing PollSet::Timeout values before a timeout has been scheduled.

Definition at line 21 of file pollset.cc.

◆ timeout_cancel()

void xdr::pollset::timeout_cancel ( Timeout & t )

Cancel a pending timeout.

Sets the PollSet::Timeout argument t to PollSet::timeout_null(), but obviously does not not affect other copies of t that will now be invalid.

Definition at line 417 of file pollset.cc.

◆ timeout_time()

std::int64_t xdr::pollset::timeout_time ( Timeout t ) const

inline

Returns the absolute time (in milliseconds) at which a timeout will run.

Definition at line 168 of file pollset.h.

◆ timeout_reschedule_at()

void xdr::pollset::timeout_reschedule_at	(	Timeout &	t,
		std::int64_t	ms
	)

Reschedule a timeout to run at a specific time.

Updates the argument t, but invalidates any other copies of t.

Definition at line 427 of file pollset.cc.

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

xdrpp/pollset.h
xdrpp/pollset.cc

Classes

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Static Protected Attributes

Detailed Description

Member Enumeration Documentation

◆ op_t

Member Function Documentation

◆ poll()

◆ pending()

◆ run()

◆ fd_cb() [1/2]

◆ fd_cb() [2/2]

◆ now_ms()

◆ timeout()

◆ timeout_at()

◆ timeout_null()

◆ timeout_cancel()

◆ timeout_time()

◆ timeout_reschedule_at()