sync

package
Version: v1.3.2 Latest Latest
Warning

This package is not in the latest version of its module.

Go to latest
Published: Mar 13, 2018 License: MIT Imports: 7 Imported by: 0

Documentation

Index

Constants

This section is empty.

Variables

View Source
var ErrStopped = errors.New("ThreadGroup already stopped")

ErrStopped is returned by ThreadGroup methods if Stop has already been called.

Functions

This section is empty.

Types

type Limiter added in v1.3.1

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

A Limiter restricts access to a resource.

Units of the resource are reserved via Request and returned via Release. Conventionally, a caller who reserves n units is responsible for ensuring that all n are eventually returned. Once the number of reserved units exceeds the Limiters limit, further calls to Request will block until sufficient units are returned via Release.

This Limiter differs from others in that it allows requesting more than the limit. This request is only fulfilled once all other units have been returned. Once the request is fulfilled, calls to Request will block until enough units have been returned to bring the total outlay below the limit. This design choice prevents any call to Request from blocking forever, striking a balance between precise resource management and flexibility.

func NewLimiter added in v1.3.1

func NewLimiter(limit int) *Limiter

NewLimiter returns a Limiter with the supplied limit.

func (*Limiter) Release added in v1.3.1

func (l *Limiter) Release(n int)

Release returns n units to l, making them available to future callers. It is legal for n to be larger than l's limit, as long as n was previously passed to Request.

func (*Limiter) Request added in v1.3.1

func (l *Limiter) Request(n int, cancel <-chan struct{}) bool

Request blocks until n units are available. If n is greater than m's limit, Request blocks until all of m's units have been released.

Request is unbiased with respect to n: calls with small n do not starve calls with large n.

Request returns true if the request was canceled, and false otherwise.

func (*Limiter) SetLimit added in v1.3.1

func (l *Limiter) SetLimit(limit int)

SetLimit sets the limit of l. It is legal to interpose calls to SetLimit between Request/Release pairs.

type RWMutex

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

RWMutex provides locking functions, and an ability to detect and remove deadlocks.

func New

func New(maxLockTime time.Duration, callDepth int) *RWMutex

New takes a maxLockTime and returns a lock. The lock will never stay locked for more than maxLockTime, instead printing an error and unlocking after maxLockTime has passed.

func (*RWMutex) Lock

func (rwm *RWMutex) Lock() int

Lock will lock the RWMutex. The return value must be used as input when calling RUnlock.

func (*RWMutex) RLock

func (rwm *RWMutex) RLock() int

RLock will read lock the RWMutex. The return value must be used as input when calling RUnlock.

func (*RWMutex) RUnlock

func (rwm *RWMutex) RUnlock(id int)

RUnlock will read unlock the RWMutex. The return value of calling RLock must be used as input.

func (*RWMutex) Unlock

func (rwm *RWMutex) Unlock(id int)

Unlock will unlock the RWMutex. The return value of calling Lock must be used as input.

type ThreadGroup added in v1.0.0

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

A ThreadGroup is a one-time-use object to manage the life cycle of a group of threads. It is a sync.WaitGroup that provides functions for coordinating actions and shutting down threads. After Stop() is called, the thread group is no longer useful.

It is safe to call Add(), Done(), and Stop() concurrently, however it is not safe to nest calls to Add(). A simple example of a nested call to add would be:

tg.Add()
tg.Add()
tg.Done()
tg.Done()

func (*ThreadGroup) Add added in v1.0.0

func (tg *ThreadGroup) Add() error

Add increments the thread group counter.

func (*ThreadGroup) AfterStop added in v1.0.1

func (tg *ThreadGroup) AfterStop(fn func())

AfterStop ensures that a function will be called after Stop() has been called and after all running routines have called Done(). The functions will be called in reverse order to how they were added, similar to defer. If Stop() has already been called, the input function will be called immediately.

The primary use of AfterStop is to allow code that opens and closes resources to be positioned next to each other. The purpose is similar to `defer`, except for resources that outlive the function which creates them.

func (*ThreadGroup) Done added in v1.0.0

func (tg *ThreadGroup) Done()

Done decrements the thread group counter.

func (*ThreadGroup) Flush added in v1.0.1

func (tg *ThreadGroup) Flush() error

Flush will block all calls to 'tg.Add' until all current routines have called 'tg.Done'. This in effect 'flushes' the module, letting it complete any tasks that are open before taking on new ones.

func (*ThreadGroup) OnStop added in v1.0.0

func (tg *ThreadGroup) OnStop(fn func())

OnStop ensures that a function will be called after Stop() has been called, and before blocking until all running routines have called Done(). It is safe to use OnStop to coordinate the closing of long-running threads. The OnStop functions will be called in the reverse order in which they were added, similar to defer. If Stop() has already been called, the input function will be called immediately.

func (*ThreadGroup) Stop added in v1.0.0

func (tg *ThreadGroup) Stop() error

Stop will close the stop channel of the thread group, then call all 'OnStop' functions in reverse order, then will wait until the thread group counter reaches zero, then will call all of the 'AfterStop' functions in reverse order. After Stop is called, most actions will return ErrStopped.

func (*ThreadGroup) StopChan added in v1.0.0

func (tg *ThreadGroup) StopChan() <-chan struct{}

StopChan provides read-only access to the ThreadGroup's stopChan. Callers should select on StopChan in order to interrupt long-running reads (such as time.After).

type TryMutex added in v1.0.1

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

TryMutex provides a mutex that allows you to attempt to grab a mutex, and then fail if the mutex is either not grabbed immediately or is not grabbed by the specified duration.

func (*TryMutex) Lock added in v1.0.1

func (tm *TryMutex) Lock()

Lock grabs a lock on the TryMutex, blocking until the lock is obtained.

func (*TryMutex) TryLock added in v1.0.1

func (tm *TryMutex) TryLock() bool

TryLock grabs a lock on the TryMutex, returning an error if the mutex is already locked.

func (*TryMutex) TryLockTimed added in v1.0.1

func (tm *TryMutex) TryLockTimed(t time.Duration) bool

TryLockTimed grabs a lock on the TryMutex, returning an error if the mutex is not grabbed after the provided duration.

func (*TryMutex) Unlock added in v1.0.1

func (tm *TryMutex) Unlock()

Unlock releases a lock on the TryMutex.

type TryRWMutex added in v1.2.0

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

TryRWMutex allows you to try to grab a RWMutex, failing if the mutex is unavailable. Standard blocking RLock and Lock calls also available.

Note that there will be inconsistencies if there are more than 1 << 20 operations active at once.

func (*TryRWMutex) Lock added in v1.2.0

func (tm *TryRWMutex) Lock()

Lock blocks until the mutex is available, and then locks it.

func (*TryRWMutex) RLock added in v1.2.0

func (tm *TryRWMutex) RLock()

RLock blocks until the mutex is available, then grabs a read lock.

func (*TryRWMutex) RUnlock added in v1.2.0

func (tm *TryRWMutex) RUnlock()

RUnlock releases a read lock on the mutex.

func (*TryRWMutex) TryLock added in v1.2.0

func (tm *TryRWMutex) TryLock() bool

TryLock grabs a lock on the mutex, returning false if the mutex is unavailable.

func (*TryRWMutex) TryRLock added in v1.2.0

func (tm *TryRWMutex) TryRLock() bool

TryRLock grabs a read lock on the mutex, returning false if the mutex is already locked.

func (*TryRWMutex) Unlock added in v1.2.0

func (tm *TryRWMutex) Unlock()

Unlock releases a lock on the mutex.

Jump to

Keyboard shortcuts

? : This menu
/ : Search site
f or F : Jump to
t or T : Toggle theme light dark auto
y or Y : Canonical URL