sync

Documentation

Index

• Variables
• type Exchanger
  • func NewExchanger[T any]() *Exchanger[T]
  • func (e *Exchanger[T]) Exchange(value T) T
• type Listener
  • func (l *Listener[T]) Chan() <-chan T
  • func (l *Listener[T]) Stop()
• type Map
  • func (m *Map[K, V]) CompareAndDelete(key K, old V) (deleted bool)
  • func (m *Map[K, V]) CompareAndSwap(key K, old, new V) bool
  • func (m *Map[K, V]) Delete(key K)
  • func (m *Map[K, V]) Load(key K) (value V, ok bool)
  • func (m *Map[K, V]) LoadAndDelete(key K) (value V, loaded bool)
  • func (m *Map[K, V]) LoadOrStore(key K, value V) (actual V, loaded bool)
  • func (m *Map[K, V]) Range(f func(key K, value V) bool)
  • func (m *Map[K, V]) Store(key K, value V)
  • func (m *Map[K, V]) Swap(key K, value V) (previous V, loaded bool)
• type Notifier
  • func NewNotifier[T any](n int) *Notifier[T]
  • func (h *Notifier[T]) Close()
  • func (h *Notifier[T]) Listen() *Listener[T]
  • func (h *Notifier[T]) Send(v T) error
  • func (h *Notifier[T]) SendNonblocking(v T) error
• type Phaser
  • func NewPhaser(parties int32) *Phaser
  • func NewPhaserWithAction(parties int32, arriveAction func(parties int32) error) *Phaser
  • func (p *Phaser) Arrive() int32
  • func (p *Phaser) ArriveAndLeave() int32
  • func (p *Phaser) ArriveAndWait() int32
  • func (p *Phaser) Arrived() int32
  • func (p *Phaser) BulkJoin(parties int32) int32
  • func (p *Phaser) ForceTermination()
  • func (p *Phaser) IsTerminated() bool
  • func (p *Phaser) Join() int32
  • func (p *Phaser) Leave() int32
  • func (p *Phaser) Parties() int32
  • func (p *Phaser) Phase() int32
  • func (p *Phaser) Wait(phase int) int32
• type Shard
  • func NewShard[T any]() *Shard[T]
  • func (s *Shard[T]) Get() *T
  • func (s *Shard[T]) Range(f func(*T))
• type TaskGroup
  • func NewTaskGroup(ctx context.Context) (*TaskGroup, context.Context)
  • func (g *TaskGroup) CancelOnFirstError(flag bool)
  • func (g *TaskGroup) Go(f func() error)
  • func (g *TaskGroup) SetLimit(n int)
  • func (g *TaskGroup) TryGo(f func() error) bool
  • func (g *TaskGroup) Wait() error
  • func (g *TaskGroup) WaitTimeout(timeout time.Duration) error

Variables

var ErrClosedChannel = errors.New("send after close")

ErrClosedChannel is returned when a send is attempted on a closed channel.

Types

type Exchanger

type Exchanger[T any] struct {
	// contains filtered or unexported fields
}

Exchanger is a synchronization primitive that allows two goroutines to exchange values. It is similar to a rendezvous point or barrier at which two goroutines swap values and proceed. It consists of two channels and each goroutine owns one channel. Each goroutine calls Exchange with the value to give to the other goroutine and receives the value from the other goroutine. It is a rendezvous because both goroutines wait for the other before exchanging values. It is a barrier because both goroutines block until both have called Exchange.

func NewExchanger

func NewExchanger[T any]() *Exchanger[T]

NewExchanger creates a new exchanger.

func (*Exchanger[T]) Exchange

func (e *Exchanger[T]) Exchange(value T) T

Exchange exchanges value between two goroutines. It returns the value received from the other goroutine.

It panics if called from neither left nor right goroutine.

If the other goroutine has not called Exchange yet, it blocks.

type Listener

type Listener[T any] struct {
	// contains filtered or unexported fields
}

Listener is a handle to a horn listener.

func (*Listener[T]) Chan

func (l *Listener[T]) Chan() <-chan T

Chan returns the channel that can be used to receive values from the horn.

func (*Listener[T]) Stop

func (l *Listener[T]) Stop()

Stop will stop listening to the horn.

type Map

type Map[K comparable, V any] struct {
	// contains filtered or unexported fields
}

Map is like a Go map[interface{}]interface{} but is safe for concurrent use by multiple goroutines without additional locking or coordination. Loads, stores, and deletes run in amortized constant time.

The Map type is specialized. Most code should use a plain Go map instead, with separate locking or coordination, for better type safety and to make it easier to maintain other invariants along with the map content.

The Map type is optimized for two common use cases: (1) when the entry for a given key is only ever written once but read many times, as in caches that only grow, or (2) when multiple goroutines read, write, and overwrite entries for disjoint sets of keys. In these two cases, use of a Map may significantly reduce lock contention compared to a Go map paired with a separate Mutex or RWMutex.

The zero Map is empty and ready for use. A Map must not be copied after first use.

In the terminology of the Go memory model, Map arranges that a write operation “synchronizes before” any read operation that observes the effect of the write, where read and write operations are defined as follows. Load, LoadAndDelete, LoadOrStore, Swap, CompareAndSwap, and CompareAndDelete are read operations; Delete, LoadAndDelete, Store, and Swap are write operations; LoadOrStore is a write operation when it returns loaded set to false; CompareAndSwap is a write operation when it returns swapped set to true; and CompareAndDelete is a write operation when it returns deleted set to true.

func (*Map[K, V]) CompareAndDelete

func (m *Map[K, V]) CompareAndDelete(key K, old V) (deleted bool)

CompareAndDelete deletes the entry for key if its value is equal to old. The old value must be of a comparable type.

If there is no current value for key in the map, CompareAndDelete returns false (even if the old value is the nil interface value).

func (*Map[K, V]) CompareAndSwap

func (m *Map[K, V]) CompareAndSwap(key K, old, new V) bool

CompareAndSwap swaps the old and new values for key if the value stored in the map is equal to old. The old value must be of a comparable type.

func (*Map[K, V]) Delete

func (m *Map[K, V]) Delete(key K)

Delete deletes the value for a key.

func (*Map[K, V]) Load

func (m *Map[K, V]) Load(key K) (value V, ok bool)

Load returns the value stored in the map for a key, or nil if no value is present. The ok result indicates whether value was found in the map.

func (*Map[K, V]) LoadAndDelete

func (m *Map[K, V]) LoadAndDelete(key K) (value V, loaded bool)

LoadAndDelete deletes the value for a key, returning the previous value if any. The loaded result reports whether the key was present.

func (*Map[K, V]) LoadOrStore

func (m *Map[K, V]) LoadOrStore(key K, value V) (actual V, loaded bool)

LoadOrStore returns the existing value for the key if present. Otherwise, it stores and returns the given value. The loaded result is true if the value was loaded, false if stored.

func (*Map[K, V]) Range

func (m *Map[K, V]) Range(f func(key K, value V) bool)

Range calls f sequentially for each key and value present in the map. If f returns false, range stops the iteration.

Range does not necessarily correspond to any consistent snapshot of the Map's contents: no key will be visited more than once, but if the value for any key is stored or deleted concurrently (including by f), Range may reflect any mapping for that key from any point during the Range call. Range does not block other methods on the receiver; even f itself may call any method on m.

Range may be O(N) with the number of elements in the map even if f returns false after a constant number of calls.

func (*Map[K, V]) Store

func (m *Map[K, V]) Store(key K, value V)

Store sets the value for a key.

func (*Map[K, V]) Swap

func (m *Map[K, V]) Swap(key K, value V) (previous V, loaded bool)

Swap swaps the value for a key and returns the previous value if any. The loaded result reports whether the key was present.

type Notifier

type Notifier[T any] struct {
	// contains filtered or unexported fields
}

func NewNotifier

func NewNotifier[T any](n int) *Notifier[T]

func (*Notifier[T]) Close

func (h *Notifier[T]) Close()

Close will close the horn and all listeners will be closed. Any subsequent calls to Send will return an error.

func (*Notifier[T]) Listen

func (h *Notifier[T]) Listen() *Listener[T]

Listen will return a new listener that can be used to receive values from the horn. The listener will be closed when the horn is closed.

func (*Notifier[T]) Send

func (h *Notifier[T]) Send(v T) error

Send will send the value to all listeners. If a listener is not ready to receive the value, it will be blocked. If the horn is closed, an error will be returned.

func (*Notifier[T]) SendNonblocking

func (h *Notifier[T]) SendNonblocking(v T) error

SendNonblocking will send the value to all listeners. If a listener is not ready to receive the value, it will be skipped. If the horn is closed, an error will be returned.

type Phaser

type Phaser struct {
	// contains filtered or unexported fields
}

Phaser is a reusable synchronization barrier, similar in functionality to java Phaser.

func NewPhaser

func NewPhaser(parties int32) *Phaser

NewPhaser creates a new Phaser instance.

func NewPhaserWithAction

func NewPhaserWithAction(parties int32, arriveAction func(parties int32) error) *Phaser

func (*Phaser) Arrive

func (p *Phaser) Arrive() int32

Arrive arrives at this phaser, without waiting for others to arrive.

func (*Phaser) ArriveAndLeave

func (p *Phaser) ArriveAndLeave() int32

ArriveAndLeave arrives at this phaser and leaves from it without waiting for others to arrive. Just like java.util.concurrent.Phaser's arriveAndDeregister() method.

func (*Phaser) ArriveAndWait

func (p *Phaser) ArriveAndWait() int32

ArriveAndWait arrives at this phaser and waits others. Just like java.util.concurrent.Phaser's arriveAndAwaitAdvance() method.

func (*Phaser) Arrived

func (p *Phaser) Arrived() int32

Phase returns the current phase number.

func (*Phaser) BulkJoin

func (p *Phaser) BulkJoin(parties int32) int32

BulkJoin adds a number of new parties to this phaser. Just like java.util.concurrent.Phaser's bulkRegister(int parties) method.

func (*Phaser) ForceTermination

func (p *Phaser) ForceTermination()

ForceTermination forces this phaser to enter termination state.

func (*Phaser) IsTerminated

func (p *Phaser) IsTerminated() bool

IsTerminated returns true if this phaser has been terminated.

func (*Phaser) Join

func (p *Phaser) Join() int32

Join adds a new party to this phaser. Just like java.util.concurrent.Phaser's register() method.

func (*Phaser) Leave

func (p *Phaser) Leave() int32

Leave leaves from this phaser without waiting for others to arrive. Just like java.util.concurrent.Phaser's deregister() method.

func (*Phaser) Parties

func (p *Phaser) Parties() int32

Parties returns the number of parties joined in this phaser.

func (*Phaser) Phase

func (p *Phaser) Phase() int32

Phase returns the current phase number.

func (*Phaser) Wait

func (p *Phaser) Wait(phase int) int32

Wait awaits the phase of this phaser to advance from the given phase value, returning immediately if the current phase is not equal to the given phase value or this phaser is terminated. Just like java.util.concurrent.Phaser's awaitAdvance(int phase) method.

type Shard

type Shard[T any] struct {
	// contains filtered or unexported fields
}

Shard is a container of values of the same type have n data of type T. Each P has a shard of n data.

func NewShard

func NewShard[T any]() *Shard[T]

NewShard creates a new Shard and initializes it with runtime.GOMAXPROCS.

func (*Shard[T]) Get

func (s *Shard[T]) Get() *T

Get gets the shard of current goroutine's P.

func (*Shard[T]) Range

func (s *Shard[T]) Range(f func(*T))

Range calls f for all data of type T in Shard.

It is not goroutine-safe to modify the Shard while iterating.

type TaskGroup

type TaskGroup struct {
	// contains filtered or unexported fields
}

A TaskGroup is a collection of goroutines working on subtasks that are part of the same overall task.

A zero TaskGroup is valid, has no limit on the number of active goroutines, and does not cancel on error.

func NewTaskGroup

func NewTaskGroup(ctx context.Context) (*TaskGroup, context.Context)

NewTaskGroup returns a new Group and an associated Context derived from ctx.

The derived Context is canceled the first time a function passed to Go returns a non-nil error in case of cancelOnErr==true or the first time Wait returns, whichever occurs first.

func (*TaskGroup) CancelOnFirstError

func (g *TaskGroup) CancelOnFirstError(flag bool)

CancelOnFirstError configures the group to cancel its context (if any) as soon as any of goutines returns a non-nil error.

Not like errgroup.Group, TaskGroup can decide whether to cancel this group or not immediately when any of goutines returns a non-nil error.

func (*TaskGroup) Go

func (g *TaskGroup) Go(f func() error)

Go calls the given function in a new goroutine. It blocks until the new goroutine can be added without the number of active goroutines in the group exceeding the configured limit.

The first call to return a non-nil error cancels the group's context, if the group was created by calling WithContext. The error will be returned by Wait.

func (*TaskGroup) SetLimit

func (g *TaskGroup) SetLimit(n int)

SetLimit limits the number of active goroutines in this group to at most n. A negative value indicates no limit.

Any subsequent call to the Go method will block until it can add an active goroutine without exceeding the configured limit.

The limit must not be modified while any goroutines in the group are active.

func (*TaskGroup) TryGo

func (g *TaskGroup) TryGo(f func() error) bool

TryGo calls the given function in a new goroutine only if the number of active goroutines in the group is currently below the configured limit.

The return value reports whether the goroutine was started.

func (*TaskGroup) Wait

func (g *TaskGroup) Wait() error

Wait blocks until all function calls from the Go method have returned, then returns the all error (if any) from them.

func (*TaskGroup) WaitTimeout

func (g *TaskGroup) WaitTimeout(timeout time.Duration) error

WaitTimeout blocks until all function calls from the Go method have returned, then returns the all error (if any) from them. Or it will return context.DeadlineExceeded if timeout. Or it will return the first error if cancelOnFirstError is true.