66 lines
1.3 KiB
Go
66 lines
1.3 KiB
Go
// Copyright (C) 2019 Storj Labs, Inc.
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// See LICENSE for copying information.
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package testqueue
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import (
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"container/list"
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"sync"
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"storj.io/storj/storage"
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)
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//Queue is a threadsafe FIFO queue implementing storage.Queue
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type Queue struct {
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mu sync.Mutex
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s *list.List
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}
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//New returns a queue suitable for testing
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func New() *Queue {
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return &Queue{s: list.New(), mu: sync.Mutex{}}
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}
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//Enqueue add a FIFO element
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func (q *Queue) Enqueue(value storage.Value) error {
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q.mu.Lock()
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defer q.mu.Unlock()
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q.s.PushBack(value)
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return nil
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}
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//Dequeue removes a FIFO element
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func (q *Queue) Dequeue() (storage.Value, error) {
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q.mu.Lock()
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defer q.mu.Unlock()
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for q.s.Len() > 0 {
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e := q.s.Front() // First element
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q.s.Remove(e) // Dequeue
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return e.Value.(storage.Value), nil
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}
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return nil, storage.ErrEmptyQueue.New("")
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}
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//Peekqueue gets upto 'limit' entries from the list queue
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func (q *Queue) Peekqueue(limit int) ([]storage.Value, error) {
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q.mu.Lock()
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defer q.mu.Unlock()
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if limit < 0 || limit > storage.LookupLimit {
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limit = storage.LookupLimit
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}
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result := make([]storage.Value, 0)
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for e := q.s.Front(); e != nil; e = e.Next() {
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result = append(result, e.Value.(storage.Value))
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limit--
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if limit <= 0 {
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break
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}
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}
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return result, nil
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}
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//Close closes the queue
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func (q *Queue) Close() error {
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return nil
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}
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