51 lines
914 B
Go
51 lines
914 B
Go
package supervisor
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import "sync"
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// booleanFuse is a data structure that can be set once to a particular value using Fuse(value).
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// Subsequent calls to Fuse() will have no effect.
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type booleanFuse struct {
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value int32
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mu sync.Mutex
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cond *sync.Cond
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}
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func newBooleanFuse() *booleanFuse {
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f := &booleanFuse{}
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f.cond = sync.NewCond(&f.mu)
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return f
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}
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// Value gets the value
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func (f *booleanFuse) Value() bool {
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// 0: unset
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// 1: set true
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// 2: set false
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f.mu.Lock()
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defer f.mu.Unlock()
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return f.value == 1
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}
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func (f *booleanFuse) Fuse(result bool) {
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f.mu.Lock()
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defer f.mu.Unlock()
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newValue := int32(2)
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if result {
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newValue = 1
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}
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if f.value == 0 {
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f.value = newValue
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f.cond.Broadcast()
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}
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}
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// Await blocks until Fuse has been called at least once.
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func (f *booleanFuse) Await() bool {
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f.mu.Lock()
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defer f.mu.Unlock()
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for f.value == 0 {
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f.cond.Wait()
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}
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return f.value == 1
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}
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