Lock

#include <Ultralight/Lock.h>

Overview

Lightweight mutex optimized for short locking periods.

Uncontended lock and unlock are a single inline atomic operation. Contended waiters spin briefly, then block in the OS until the lock is released (no CPU is consumed while waiting).

Can be used in place of std::mutex since it implements the STL's Lockable interface.

Note

This lock is not recursive: locking it again from the thread that already holds it will deadlock. Debug builds assert when this is attempted.

Public Member Functions
constexpr	Lock ()=default
UL_ALWAYS_INLINE void	lock () noexcept
UL_ALWAYS_INLINE bool	try_lock () noexcept
UL_ALWAYS_INLINE void	unlock () noexcept

Protected Member Functions
	Lock (const Lock &)=delete
Lock &	operator= (const Lock &)=delete
void	contended_lock () noexcept
void	contended_unlock () noexcept

Static Protected Member Functions
static uint32_t	current_thread_id () noexcept

Protected Attributes
std::atomic< uint32_t >	state_ = { kUnlocked }
std::atomic< uint32_t >	owner_ = { 0 }

Static Protected Attributes
static constexpr uint32_t	kUnlocked = 0
static constexpr uint32_t	kLocked = 1
static constexpr uint32_t	kLockedContended = 2

Constructor & Destructor Documentation

Lock() [1/2]

Lock ( )

constexprdefault

Lock() [2/2]

Lock ( const Lock & )

protecteddelete

Member Function Documentation

contended_lock()

void contended_lock ( )

protectednoexcept

contended_unlock()

void contended_unlock ( )

protectednoexcept

current_thread_id()

uint32_t current_thread_id ( )

staticprotectednoexcept

lock()

UL_ALWAYS_INLINE void lock ( )

inlinenoexcept

operator=()

Lock & operator= ( const Lock & )

protecteddelete

try_lock()

UL_ALWAYS_INLINE bool try_lock ( )

inlinenoexcept

unlock()

UL_ALWAYS_INLINE void unlock ( )

inlinenoexcept

Member Data Documentation

kLocked

uint32_t kLocked = 1

staticconstexprprotected

kLockedContended

uint32_t kLockedContended = 2

staticconstexprprotected

kUnlocked

uint32_t kUnlocked = 0

staticconstexprprotected

owner_

std::atomic<uint32_t> owner_ = { 0 }

protected

state_

std::atomic<uint32_t> state_ = { kUnlocked }

protected

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

• Ultralight/Lock.h