mirror of
https://github.com/etcd-io/etcd.git
synced 2024-09-27 06:25:44 +00:00
109 lines
3.1 KiB
Go
109 lines
3.1 KiB
Go
// Copyright 2016 CoreOS, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package recipe
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import (
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"github.com/coreos/etcd/Godeps/_workspace/src/golang.org/x/net/context"
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"github.com/coreos/etcd/clientv3"
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pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
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)
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type Range struct {
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kv pb.KVClient
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key []byte
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rev int64
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keyEnd []byte
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}
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func NewRange(client *clientv3.Client, key string) *Range {
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return NewRangeRev(client, key, 0)
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}
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func NewRangeRev(client *clientv3.Client, key string, rev int64) *Range {
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return &Range{client.KV, []byte(key), rev, prefixEnd(key)}
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}
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// Prefix performs a RangeRequest to get keys matching <key>*
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func (r *Range) Prefix() (*pb.RangeResponse, error) {
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return r.kv.Range(
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context.TODO(),
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&pb.RangeRequest{
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Key: prefixNext(string(r.key)),
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RangeEnd: r.keyEnd,
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Revision: r.rev})
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}
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// OpenInterval gets the keys in the set <key>* - <key>
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func (r *Range) OpenInterval() (*pb.RangeResponse, error) {
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return r.kv.Range(
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context.TODO(),
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&pb.RangeRequest{Key: r.key, RangeEnd: r.keyEnd, Revision: r.rev})
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}
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func (r *Range) FirstKey() (*pb.RangeResponse, error) {
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return r.topTarget(pb.RangeRequest_ASCEND, pb.RangeRequest_KEY)
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}
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func (r *Range) LastKey() (*pb.RangeResponse, error) {
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return r.topTarget(pb.RangeRequest_DESCEND, pb.RangeRequest_KEY)
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}
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func (r *Range) FirstRev() (*pb.RangeResponse, error) {
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return r.topTarget(pb.RangeRequest_ASCEND, pb.RangeRequest_MOD)
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}
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func (r *Range) LastRev() (*pb.RangeResponse, error) {
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return r.topTarget(pb.RangeRequest_DESCEND, pb.RangeRequest_MOD)
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}
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func (r *Range) FirstCreate() (*pb.RangeResponse, error) {
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return r.topTarget(pb.RangeRequest_ASCEND, pb.RangeRequest_MOD)
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}
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func (r *Range) LastCreate() (*pb.RangeResponse, error) {
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return r.topTarget(pb.RangeRequest_DESCEND, pb.RangeRequest_MOD)
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}
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// topTarget gets the first key for a given sort order and target
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func (r *Range) topTarget(order pb.RangeRequest_SortOrder, target pb.RangeRequest_SortTarget) (*pb.RangeResponse, error) {
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return r.kv.Range(
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context.TODO(),
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&pb.RangeRequest{
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Key: r.key,
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RangeEnd: r.keyEnd,
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Limit: 1,
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Revision: r.rev,
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SortOrder: order,
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SortTarget: target})
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}
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// prefixNext returns the first key possibly matched by <prefix>* - <prefix>
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func prefixNext(prefix string) []byte {
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return append([]byte(prefix), 0)
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}
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// prefixEnd returns the last key possibly matched by <prefix>*
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func prefixEnd(prefix string) []byte {
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keyEnd := []byte(prefix)
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for i := len(keyEnd) - 1; i >= 0; i-- {
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if keyEnd[i] < 0xff {
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keyEnd[i] = keyEnd[i] + 1
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keyEnd = keyEnd[:i+1]
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break
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}
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}
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return keyEnd
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}
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