97 lines
2.1 KiB
Go
97 lines
2.1 KiB
Go
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// Copyright (C) 2018 Storj Labs, Inc.
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// See LICENSE for copying information.
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package storage
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import (
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"bytes"
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"sort"
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)
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// IteratorFunc implements basic iterator
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type IteratorFunc func(item *ListItem) bool
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// Next returns the next item
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func (next IteratorFunc) Next(item *ListItem) bool { return next(item) }
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// SelectPrefixed keeps only items that have prefix
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// items will be reused and modified
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// TODO: remove this
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func SelectPrefixed(items Items, prefix []byte) Items {
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result := items[:0]
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for _, item := range items {
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if bytes.HasPrefix(item.Key, prefix) {
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result = append(result, item)
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}
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}
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return result
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}
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// SortAndCollapse sorts items and combines elements based on Delimiter
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// items will be reused and modified
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// TODO: remove this
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func SortAndCollapse(items Items, prefix []byte) Items {
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sort.Sort(items)
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result := items[:0]
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var currentPrefix []byte
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var prefixed bool
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for _, item := range items {
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if prefixed {
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if bytes.HasPrefix(item.Key, currentPrefix) {
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continue
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}
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prefixed = false
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}
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if p := bytes.IndexByte(item.Key[len(prefix):], Delimiter); p >= 0 {
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currentPrefix = item.Key[:len(prefix)+p+1]
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prefixed = true
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result = append(result, ListItem{
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Key: currentPrefix,
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IsPrefix: true,
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})
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} else {
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result = append(result, item)
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}
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}
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return result
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}
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// ReverseItems reverses items in the list
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// items will be reused and modified
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// TODO: remove this
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func ReverseItems(items Items) Items {
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for i := len(items)/2 - 1; i >= 0; i-- {
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k := len(items) - 1 - i
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items[i], items[k] = items[k], items[i]
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}
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return items
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}
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// ReverseKeys reverses the list of keys
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func ReverseKeys(keys Keys) Keys {
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for i := len(keys)/2 - 1; i >= 0; i-- {
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k := len(keys) - 1 - i
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keys[i], keys[k] = keys[k], keys[i]
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}
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return keys
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}
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// StaticIterator implements an iterator over list of items
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type StaticIterator struct {
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Items Items
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Index int
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}
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// Next returns the next item from the iterator
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func (it *StaticIterator) Next(item *ListItem) bool {
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if it.Index >= len(it.Items) {
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return false
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}
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*item = it.Items[it.Index]
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it.Index++
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return true
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}
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