sync

Documentation

Index

• Constants
• Variables
• func Go(ctx Context, f func(ctx Context))
• func Select(ctx Context, cases ...SelectCase)
• func WithCancel(parent Context) (ctx Context, cancel CancelFunc)
• type CancelFunc
• type Channel
  • func NewBufferedChannel[T any](size int) Channel[T]
  • func NewChannel[T any]() Channel[T]
• type ChannelInternal
• type Context
  • func Background() Context
  • func NewDisconnectedContext(ctx Context) Context
  • func WithValue(parent Context, key, val interface{}) Context
• type Coroutine
  • func NewCoroutine(ctx Context, fn func(ctx Context) error) Coroutine
• type Future
• type Scheduler
  • func NewScheduler() Scheduler
• type SelectCase
  • func Await[T any](f Future[T], handler func(ctx Context, f Future[T])) SelectCase
  • func Default(handler func(ctx Context)) SelectCase
  • func Receive[T any](c Channel[T], handler func(ctx Context, v T, ok bool)) SelectCase
• type SettableFuture
  • func NewFuture[T any]() SettableFuture[T]
• type WaitGroup
  • func NewWaitGroup() WaitGroup

Constants

const DeadlockDetection = 40 * time.Second

Variables

var Canceled = errors.New("context canceled")

Canceled is the error returned by Context.Err when the context is canceled.

Functions

func Go

func Go(ctx Context, f func(ctx Context))

func Select

func Select(ctx Context, cases ...SelectCase)

func WithCancel

func WithCancel(parent Context) (ctx Context, cancel CancelFunc)

WithCancel returns a copy of parent with a new Done channel. The returned context's Done channel is closed when the returned cancel function is called or when the parent context's Done channel is closed, whichever happens first.

Canceling this context releases resources associated with it, so code should call cancel as soon as the operations running in this Context complete.

Types

type CancelFunc

type CancelFunc func()

A CancelFunc tells an operation to abandon its work. A CancelFunc does not wait for the work to stop. A CancelFunc may be called by multiple goroutines simultaneously. After the first call, subsequent calls to a CancelFunc do nothing.

type Channel

type Channel[T any] interface {
	Send(ctx Context, v T)

	SendNonblocking(ctx Context, v T) (ok bool)

	Receive(ctx Context) (v T, ok bool)

	ReceiveNonblocking(ctx Context) (v T, ok bool)

	Close()
}

func NewBufferedChannel

func NewBufferedChannel[T any](size int) Channel[T]

func NewChannel

func NewChannel[T any]() Channel[T]

type ChannelInternal

type ChannelInternal[T any] interface {
	Closed() bool

	ReceiveNonBlocking(ctx Context) (v T, ok bool)

	AddReceiveCallback(cb func(v T, ok bool))
}

type Context

type Context interface {
	// Done returns a channel that's closed when work done on behalf of this
	// context should be canceled. Done may return nil if this context can
	// never be canceled. Successive calls to Done return the same value.
	// The close of the Done channel may happen asynchronously,
	// after the cancel function returns.
	//
	// WithCancel arranges for Done to be closed when cancel is called;
	// WithDeadline arranges for Done to be closed when the deadline
	// expires; WithTimeout arranges for Done to be closed when the timeout
	// elapses.
	//
	// Done is provided for use in select statements:
	//
	//  // Stream generates values with DoSomething and sends them to out
	//  // until DoSomething returns an error or ctx.Done is closed.
	//  func Stream(ctx Context, out chan<- Value) error {
	//  	for {
	//  		v, err := DoSomething(ctx)
	//  		if err != nil {
	//  			return err
	//  		}
	//  		select {
	//  		case <-ctx.Done():
	//  			return ctx.Err()
	//  		case out <- v:
	//  		}
	//  	}
	//  }
	//
	// See https://blog.golang.org/pipelines for more examples of how to use
	// a Done channel for cancellation.
	Done() Channel[struct{}]

	// If Done is not yet closed, Err returns nil.
	// If Done is closed, Err returns a non-nil error explaining why:
	// Canceled if the context was canceled
	// or DeadlineExceeded if the context's deadline passed.
	// After Err returns a non-nil error, successive calls to Err return the same error.
	Err() error

	// Value returns the value associated with this context for key, or nil
	// if no value is associated with key. Successive calls to Value with
	// the same key returns the same result.
	//
	// Use context values only for request-scoped data that transits
	// processes and API boundaries, not for passing optional parameters to
	// functions.
	//
	// A key identifies a specific value in a Context. Functions that wish
	// to store values in Context typically allocate a key in a global
	// variable then use that key as the argument to context.WithValue and
	// Context.Value. A key can be any type that supports equality;
	// packages should define keys as an unexported type to avoid
	// collisions.
	//
	// Packages that define a Context key should provide type-safe accessors
	// for the values stored using that key:
	//
	// 	// Package user defines a User type that's stored in Contexts.
	// 	package user
	//
	// 	import "context"
	//
	// 	// User is the type of value stored in the Contexts.
	// 	type User struct {...}
	//
	// 	// key is an unexported type for keys defined in this package.
	// 	// This prevents collisions with keys defined in other packages.
	// 	type key int
	//
	// 	// userKey is the key for user.User values in Contexts. It is
	// 	// unexported; clients use user.NewContext and user.FromContext
	// 	// instead of using this key directly.
	// 	var userKey key
	//
	// 	// NewContext returns a new Context that carries value u.
	// 	func NewContext(ctx Context, u *User) Context {
	// 		return context.WithValue(ctx, userKey, u)
	// 	}
	//
	// 	// FromContext returns the User value stored in ctx, if any.
	// 	func FromContext(ctx Context) (*User, bool) {
	// 		u, ok := ctx.Value(userKey).(*User)
	// 		return u, ok
	// 	}
	Value(key interface{}) interface{}
}

A Context carries a deadline, a cancellation signal, and other values across API boundaries.

Context's methods may be called by multiple goroutines simultaneously.

func Background

func Background() Context

Background returns a non-nil, empty Context. It is never canceled, has no values, and has no deadline. It is typically used by the main function, initialization, and tests, and as the top-level Context for incoming requests.

func NewDisconnectedContext

func NewDisconnectedContext(ctx Context) Context

func WithValue

func WithValue(parent Context, key, val interface{}) Context

WithValue returns a copy of parent in which the value associated with key is val.

Use context Values only for request-scoped data that transits processes and APIs, not for passing optional parameters to functions.

The provided key must be comparable and should not be of type string or any other built-in type to avoid collisions between packages using context. Users of WithValue should define their own types for keys. To avoid allocating when assigning to an interface{}, context keys often have concrete type struct{}. Alternatively, exported context key variables' static type should be a pointer or interface.

type Coroutine

type Coroutine interface {
	// Execute continues execution of a blocked corouting and waits until
	// it is finished or blocked again
	Execute()

	// Yield yields execution and stops coroutine execution
	Yield()

	// Exit prevents a _blocked_ Coroutine from continuing
	Exit()

	Blocked() bool
	Finished() bool
	Progress() bool

	Error() error

	SetScheduler(s Scheduler)
}

func NewCoroutine

func NewCoroutine(ctx Context, fn func(ctx Context) error) Coroutine

type Future

type Future[T any] interface {
	// Get returns the value if set, blocks otherwise
	Get(ctx Context) (T, error)
}

type Scheduler

type Scheduler interface {
	// Starts a new co-routine and tracks it in this scheduler
	NewCoroutine(ctx Context, fn func(Context) error)

	// Execute executes all coroutines until they are all blocked
	Execute(ctx Context) error

	RunningCoroutines() int

	Exit(ctx Context)
}

func NewScheduler

func NewScheduler() Scheduler

type SelectCase

type SelectCase interface {
	Ready() bool
	Handle(Context)
}

func Await

func Await[T any](f Future[T], handler func(ctx Context, f Future[T])) SelectCase

func Default

func Default(handler func(ctx Context)) SelectCase

func Receive

func Receive[T any](c Channel[T], handler func(ctx Context, v T, ok bool)) SelectCase

type SettableFuture

type SettableFuture[T any] interface {
	Future[T]

	// Set stores the value and unblocks any waiting consumers
	Set(v T, err error)
}

func NewFuture

func NewFuture[T any]() SettableFuture[T]

type WaitGroup

type WaitGroup interface {
	Add(delta int)
	Done()
	Wait(ctx Context)
}

func NewWaitGroup

func NewWaitGroup() WaitGroup