77 lines
1.9 KiB
Go
77 lines
1.9 KiB
Go
package pool
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import "sync/atomic"
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// WorkUnit contains a single uint of works values
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type WorkUnit interface {
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// Wait blocks until WorkUnit has been processed or cancelled
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Wait()
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// Value returns the work units return value
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Value() interface{}
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// Error returns the Work Unit's error
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Error() error
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// Cancel cancels this specific unit of work, if not already committed
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// to processing.
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Cancel()
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// IsCancelled returns if the Work Unit has been cancelled.
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// NOTE: After Checking IsCancelled(), if it returns false the
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// Work Unit can no longer be cancelled and will use your returned values.
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IsCancelled() bool
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}
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var _ WorkUnit = new(workUnit)
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// workUnit contains a single unit of works values
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type workUnit struct {
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value interface{}
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err error
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done chan struct{}
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fn WorkFunc
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cancelled atomic.Value
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cancelling atomic.Value
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writing atomic.Value
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}
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// Cancel cancels this specific unit of work, if not already committed to processing.
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func (wu *workUnit) Cancel() {
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wu.cancelWithError(&ErrCancelled{s: errCancelled})
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}
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func (wu *workUnit) cancelWithError(err error) {
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wu.cancelling.Store(struct{}{})
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if wu.writing.Load() == nil && wu.cancelled.Load() == nil {
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wu.cancelled.Store(struct{}{})
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wu.err = err
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close(wu.done)
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}
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}
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// Wait blocks until WorkUnit has been processed or cancelled
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func (wu *workUnit) Wait() {
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<-wu.done
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}
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// Value returns the work units return value
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func (wu *workUnit) Value() interface{} {
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return wu.value
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}
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// Error returns the Work Unit's error
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func (wu *workUnit) Error() error {
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return wu.err
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}
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// IsCancelled returns if the Work Unit has been cancelled.
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// NOTE: After Checking IsCancelled(), if it returns false the
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// Work Unit can no longer be cancelled and will use your returned values.
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func (wu *workUnit) IsCancelled() bool {
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wu.writing.Store(struct{}{}) // ensure that after this check we are committed as cannot be cancelled if not aalready
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return wu.cancelled.Load() != nil
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}
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