Documentation
¶
Index ¶
- type Broadcast
- func (c *Broadcast) HoldLock(cb func(broadcast func(), getWaitCh func() <-chan struct{}))
- func (c *Broadcast) HoldLockMaybeAsync(cb func(broadcast func(), getWaitCh func() <-chan struct{}))
- func (c *Broadcast) TryHoldLock(cb func(broadcast func(), getWaitCh func() <-chan struct{})) bool
- func (c *Broadcast) Wait(ctx context.Context, ...) error
Examples ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Broadcast ¶
type Broadcast struct {
// contains filtered or unexported fields
}
Broadcast implements notifying waiters via a channel.
The zero-value of this struct is valid.
Example ¶
// b guards currValue
var b Broadcast
var currValue int
go func() {
// 0 to 9 inclusive
for i := range 10 {
<-time.After(time.Millisecond * 20)
b.HoldLock(func(broadcast func(), getWaitCh func() <-chan struct{}) {
currValue = i
broadcast()
})
}
}()
var waitCh <-chan struct{}
var gotValue int
for {
b.HoldLock(func(broadcast func(), getWaitCh func() <-chan struct{}) {
gotValue = currValue
waitCh = getWaitCh()
})
// last value
if gotValue == 9 {
// success
break
}
// otherwise keep waiting
<-waitCh
}
fmt.Printf("waited for value to increment: %v\n", gotValue)
Output: waited for value to increment: 9
func (*Broadcast) HoldLock ¶ added in v1.6.0
func (c *Broadcast) HoldLock(cb func(broadcast func(), getWaitCh func() <-chan struct{}))
HoldLock locks the mutex and calls the callback.
broadcast closes the wait channel, if any. getWaitCh returns a channel that will be closed when broadcast is called.
func (*Broadcast) HoldLockMaybeAsync ¶ added in v1.11.1
func (c *Broadcast) HoldLockMaybeAsync(cb func(broadcast func(), getWaitCh func() <-chan struct{}))
HoldLockMaybeAsync locks the mutex and calls the callback if possible. If the mutex cannot be locked right now, starts a new Goroutine to wait for it.
func (*Broadcast) TryHoldLock ¶ added in v1.25.7
TryHoldLock attempts to lock the mutex and call the callback. It returns true if the lock was acquired and the callback was called, false otherwise.
func (*Broadcast) Wait ¶ added in v1.25.5
func (c *Broadcast) Wait(ctx context.Context, cb func(broadcast func(), getWaitCh func() <-chan struct{}) (bool, error)) error
Wait waits for the cb to return true or an error before returning. When the broadcast channel is broadcasted, re-calls cb again to re-check the value. cb is called while the mutex is locked. Returns context.Canceled if ctx is canceled.
Example ¶
// b guards currValue
var b Broadcast
var currValue int
go func() {
// 0 to 9 inclusive
for i := range 10 {
<-time.After(time.Millisecond * 20)
b.HoldLock(func(broadcast func(), getWaitCh func() <-chan struct{}) {
currValue = i
broadcast()
})
}
}()
ctx := context.Background()
var gotValue int
err := b.Wait(ctx, func(broadcast func(), getWaitCh func() <-chan struct{}) (bool, error) {
gotValue = currValue
return gotValue == 9, nil
})
if err != nil {
fmt.Printf("failed to wait for value: %v", err.Error())
return
}
fmt.Printf("waited for value to increment: %v\n", gotValue)
Output: waited for value to increment: 9
Source Files