vlink::DeadlineTimer Class Reference

Atomic absolute-deadline timer for lock-free timeout detection. More...

#include <deadline_timer.h>

Collaboration diagram for vlink::DeadlineTimer:

Public Types
using	Accuracy = ElapsedTimer::Accuracy
	Time precision. Aliases ElapsedTimer::Accuracy for convenience.

Public Member Functions
	DeadlineTimer () noexcept
	Default constructor. Creates an invalid (unset) deadline.
	DeadlineTimer (int64_t interval, Accuracy accuracy=ElapsedTimer::kMilli) noexcept
	Constructs a DeadlineTimer that expires interval time units from now.
	DeadlineTimer (const DeadlineTimer &other) noexcept
	Copy constructor.
	DeadlineTimer (DeadlineTimer &&other) noexcept
	Move constructor.
	~DeadlineTimer () noexcept
	Destructor.
DeadlineTimer &	operator= (const DeadlineTimer &other) noexcept
	Copy-assignment operator.
DeadlineTimer &	operator= (DeadlineTimer &&other) noexcept
	Move-assignment operator.
void	set_deadline (int64_t interval) noexcept
	Sets the deadline to interval time units from now.
void	set_deadline_abs (uint64_t abs_deadline) noexcept
	Sets an explicit absolute deadline timestamp.
void	reset () noexcept
	Resets the deadline to 0, making the timer invalid again.
uint64_t	deadline () const noexcept
	Returns the stored absolute deadline timestamp.
int64_t	remaining_time () const noexcept
	Returns the time remaining until the deadline.
bool	has_expired () const noexcept
	Returns true if the current time is past the stored deadline.
bool	is_valid () const noexcept
	Returns true if the deadline has been explicitly set (non-zero).
Accuracy	get_accuracy () const noexcept
	Returns the time precision configured for this timer.

Detailed Description

Atomic absolute-deadline timer for lock-free timeout detection.

Stores an absolute expiry time (monotonic CPU timestamp) in a 64-bit atomic. Concurrent has_expired() / remaining_time() reads from multiple threads are safe without external locking.

Member Typedef Documentation

Accuracy

using vlink::DeadlineTimer::Accuracy = ElapsedTimer::Accuracy

Time precision. Aliases ElapsedTimer::Accuracy for convenience.

Constructor & Destructor Documentation

DeadlineTimer() [1/4]

vlink::DeadlineTimer::DeadlineTimer ( )

noexcept

Default constructor. Creates an invalid (unset) deadline.

is_valid() returns false and has_expired() returns false until set_deadline() or set_deadline_abs() is called.

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DeadlineTimer() [2/4]

vlink::DeadlineTimer::DeadlineTimer ( int64_t interval, Accuracy accuracy = ElapsedTimer::kMilli )

explicitnoexcept

Constructs a DeadlineTimer that expires interval time units from now.

The absolute deadline is computed as the current monotonic timestamp plus interval. If interval <= 0 the timer is reset to the invalid state (equivalent to reset()).

Parameters

interval	Duration until expiry, in accuracy units.
accuracy	Time precision (default: ElapsedTimer::kMilli).

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DeadlineTimer() [3/4]

vlink::DeadlineTimer::DeadlineTimer ( const DeadlineTimer & other )

noexcept

Copy constructor.

Parameters

other

The source timer.

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DeadlineTimer() [4/4]

vlink::DeadlineTimer::DeadlineTimer ( DeadlineTimer && other )

noexcept

Move constructor.

Parameters

other

The source timer (moved from).

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~DeadlineTimer()

vlink::DeadlineTimer::~DeadlineTimer ( )

noexcept

Destructor.

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Member Function Documentation

deadline()

uint64_t vlink::DeadlineTimer::deadline ( ) const

nodiscardnoexcept

Returns the stored absolute deadline timestamp.

A value of 0 means the timer has not been set (see is_valid()).

Returns

Absolute deadline in the configured accuracy units.

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get_accuracy()

Accuracy vlink::DeadlineTimer::get_accuracy ( ) const

nodiscardnoexcept

Returns the time precision configured for this timer.

Returns

The Accuracy value set at construction.

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has_expired()

bool vlink::DeadlineTimer::has_expired ( ) const

nodiscardnoexcept

Returns true if the current time is past the stored deadline.

Equivalent to remaining_time() <= 0 when is_valid() is true. Always returns false for an unset (invalid) timer.

Returns

true if expired, false otherwise.

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is_valid()

bool vlink::DeadlineTimer::is_valid ( ) const

nodiscardnoexcept

Returns true if the deadline has been explicitly set (non-zero).

Returns

true if the timer is valid (deadline != 0).

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operator=() [1/2]

DeadlineTimer & vlink::DeadlineTimer::operator= ( const DeadlineTimer & other )

noexcept

Copy-assignment operator.

Parameters

other

The source timer.

Returns

A reference to *this.

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operator=() [2/2]

DeadlineTimer & vlink::DeadlineTimer::operator= ( DeadlineTimer && other )

noexcept

Move-assignment operator.

Parameters

other

The source timer.

Returns

A reference to *this.

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remaining_time()

int64_t vlink::DeadlineTimer::remaining_time ( ) const

nodiscardnoexcept

Returns the time remaining until the deadline.

Computed as (deadline - current_cpu_timestamp). Returns 0 when the timer is invalid or already expired.

Returns

Remaining time in the configured accuracy units. A return value of 0 means invalid or expired.

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reset()

void vlink::DeadlineTimer::reset ( )

noexcept

Resets the deadline to 0, making the timer invalid again.

After reset(), is_valid() returns false.

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set_deadline()

void vlink::DeadlineTimer::set_deadline ( int64_t interval )

noexcept

Sets the deadline to interval time units from now.

Reads the current monotonic timestamp and adds interval to produce the absolute deadline. A value of 0 or less clears the timer and makes it invalid.

Parameters

interval

Duration until expiry in the configured accuracy units.

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set_deadline_abs()

void vlink::DeadlineTimer::set_deadline_abs ( uint64_t abs_deadline )

noexcept

Sets an explicit absolute deadline timestamp.

The value must be in the same unit and time base as the Accuracy configured for this timer. Typically obtain it via ElapsedTimer::get_cpu_timestamp(accuracy).

Parameters

abs_deadline

Absolute monotonic timestamp of the deadline.

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

• include/vlink/base/deadline_timer.h