34 lines
641 B
Go
34 lines
641 B
Go
// Copyright 2017 The OPA Authors. All rights reserved.
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// Use of this source code is governed by an Apache2
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// license that can be found in the LICENSE file.
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package topdown
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import (
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"sync/atomic"
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)
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// Cancel defines the interface for cancelling topdown queries. Cancel
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// operations are thread-safe and idempotent.
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type Cancel interface {
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Cancel()
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Cancelled() bool
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}
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type cancel struct {
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flag int32
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}
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// NewCancel returns a new Cancel object.
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func NewCancel() Cancel {
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return &cancel{}
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}
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func (c *cancel) Cancel() {
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atomic.StoreInt32(&c.flag, 1)
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}
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func (c *cancel) Cancelled() bool {
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return atomic.LoadInt32(&c.flag) != 0
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}
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