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30 lines
1010 B
30 lines
1010 B
5 years ago
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// Copyright 2020 The Gitea Authors. All rights reserved.
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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package queue
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import (
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"fmt"
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)
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// UniqueQueue defines a queue which guarantees only one instance of same
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// data is in the queue. Instances with same identity will be
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// discarded if there is already one in the line.
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//
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// This queue is particularly useful for preventing duplicated task
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// of same purpose - please note that this does not guarantee that a particular
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// task cannot be processed twice or more at the same time. Uniqueness is
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// only guaranteed whilst the task is waiting in the queue.
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//
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// Users of this queue should be careful to push only the identifier of the
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// data
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type UniqueQueue interface {
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Queue
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PushFunc(Data, func() error) error
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Has(Data) (bool, error)
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}
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// ErrAlreadyInQueue is returned when trying to push data to the queue that is already in the queue
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var ErrAlreadyInQueue = fmt.Errorf("already in queue")
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