41 lines
770 B
Go
41 lines
770 B
Go
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package cond
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import (
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"sync"
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)
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// NewStatefulCond returns a stateful version of sync.Cond . This cond will
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// never block on `Wait()` if `Signal()` has been called after the `Wait()` last
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// returned. This is useful for avoiding to take a lock on `cond.Locker` for
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// signalling.
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func NewStatefulCond(l sync.Locker) *StatefulCond {
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sc := &StatefulCond{main: l}
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sc.c = sync.NewCond(&sc.mu)
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return sc
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}
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type StatefulCond struct {
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main sync.Locker
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mu sync.Mutex
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c *sync.Cond
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signalled bool
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}
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func (s *StatefulCond) Wait() {
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s.main.Unlock()
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s.mu.Lock()
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if !s.signalled {
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s.c.Wait()
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}
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s.signalled = false
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s.mu.Unlock()
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s.main.Lock()
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}
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func (s *StatefulCond) Signal() {
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s.mu.Lock()
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s.signalled = true
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s.c.Signal()
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s.mu.Unlock()
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}
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