112 lines
2.5 KiB
Go
112 lines
2.5 KiB
Go
/*
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Copyright 2014 CoreOS, Inc.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package wal
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import (
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"fmt"
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"log"
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"os"
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)
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func Exist(dirpath string) bool {
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names, err := readDir(dirpath)
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if err != nil {
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return false
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}
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return len(names) != 0
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}
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// searchIndex returns the last array index of names whose raft index section is
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// equal to or smaller than the given index.
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// The given names MUST be sorted.
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func searchIndex(names []string, index uint64) (int, bool) {
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for i := len(names) - 1; i >= 0; i-- {
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name := names[i]
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_, curIndex, err := parseWalName(name)
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if err != nil {
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panic("parse correct name error")
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}
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if index >= curIndex {
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return i, true
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}
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}
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return -1, false
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}
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// names should have been sorted based on sequence number.
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// isValidSeq checks whether seq increases continuously.
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func isValidSeq(names []string) bool {
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var lastSeq uint64
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for _, name := range names {
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curSeq, _, err := parseWalName(name)
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if err != nil {
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panic("parse correct name error")
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}
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if lastSeq != 0 && lastSeq != curSeq-1 {
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return false
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}
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lastSeq = curSeq
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}
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return true
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}
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// readDir returns the filenames in wal directory.
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func readDir(dirpath string) ([]string, error) {
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dir, err := os.Open(dirpath)
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if err != nil {
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return nil, err
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}
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defer dir.Close()
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names, err := dir.Readdirnames(-1)
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if err != nil {
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return nil, err
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}
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return names, nil
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}
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func checkWalNames(names []string) []string {
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wnames := make([]string, 0)
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for _, name := range names {
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if _, _, err := parseWalName(name); err != nil {
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log.Printf("parse %s: %v", name, err)
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continue
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}
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wnames = append(wnames, name)
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}
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return wnames
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}
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func parseWalName(str string) (seq, index uint64, err error) {
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var num int
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num, err = fmt.Sscanf(str, "%016x-%016x.wal", &seq, &index)
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if num != 2 && err == nil {
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err = fmt.Errorf("bad wal name: %s", str)
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}
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return
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}
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func walName(seq, index uint64) string {
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return fmt.Sprintf("%016x-%016x.wal", seq, index)
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}
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func max(a, b int64) int64 {
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if a > b {
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return a
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}
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return b
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}
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