95 lines
2.2 KiB
Go
95 lines
2.2 KiB
Go
// Copyright (C) 2019 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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"context"
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)
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// ListOptions are items that are optional for the LIST method.
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type ListOptions struct {
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Prefix Key
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StartAfter Key // StartAfter is relative to Prefix
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Recursive bool
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IncludeValue bool
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Limit int
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}
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// ListV2 lists all keys corresponding to ListOptions.
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// limit is capped to LookupLimit.
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//
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// more indicates if the result was truncated. If false
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// then the result []ListItem includes all requested keys.
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// If true then the caller must call List again to get more
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// results by setting `StartAfter` appropriately.
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func ListV2(ctx context.Context, store KeyValueStore, opts ListOptions) (result Items, more bool, err error) {
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defer mon.Task()(&ctx)(&err)
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limit := opts.Limit
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if limit <= 0 || limit > store.LookupLimit() {
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limit = store.LookupLimit()
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}
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more = true
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first := opts.StartAfter
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iterate := func(ctx context.Context, it Iterator) error {
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var item ListItem
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skipFirst := true
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for ; limit > 0; limit-- {
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if !it.Next(ctx, &item) {
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more = false
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return nil
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}
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relativeKey := item.Key[len(opts.Prefix):]
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if skipFirst {
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skipFirst = false
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if relativeKey.Equal(first) {
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// skip the first element in iteration
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// if it matches the search key
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limit++
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continue
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}
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}
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task := mon.TaskNamed("appending_to_results")(nil)
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if opts.IncludeValue {
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result = append(result, ListItem{
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Key: CloneKey(relativeKey),
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Value: CloneValue(item.Value),
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IsPrefix: item.IsPrefix,
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})
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} else {
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result = append(result, ListItem{
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Key: CloneKey(relativeKey),
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IsPrefix: item.IsPrefix,
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})
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}
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task(nil)
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}
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// we still need to consume one item for the more flag
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more = it.Next(ctx, &item)
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return nil
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}
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var firstFull Key
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if !opts.StartAfter.IsZero() {
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firstFull = joinKey(opts.Prefix, opts.StartAfter)
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}
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err = store.Iterate(ctx, IterateOptions{
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Prefix: opts.Prefix,
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First: firstFull,
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Recurse: opts.Recursive,
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Limit: limit,
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}, iterate)
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return result, more, err
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}
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func joinKey(a, b Key) Key {
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return append(append(Key{}, a...), b...)
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}
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