minio/cmd/metacache-marker.go

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/*
* MinIO Cloud Storage, (C) 2020 MinIO, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package cmd
import (
"context"
"fmt"
"strings"
"github.com/minio/minio/cmd/logger"
)
// markerTagVersion is the marker version.
// Should not need to be updated unless a fundamental change is made to the marker format.
const markerTagVersion = "v1"
// parseMarker will parse a marker possibly encoded with encodeMarker
func parseMarker(s string) (marker, uuid string) {
if !strings.Contains(s, "[minio_cache:"+markerTagVersion) {
return s, ""
}
start := strings.LastIndex(s, "[")
marker = s[:start]
end := strings.LastIndex(s, "]")
tag := strings.Trim(s[start:end], "[]")
tags := strings.Split(tag, ",")
for _, tag := range tags {
kv := strings.Split(tag, ":")
if len(kv) < 2 {
continue
}
switch kv[0] {
case "minio_cache":
if kv[1] != markerTagVersion {
break
}
case "id":
uuid = kv[1]
default:
// Ignore unknown
}
}
return
}
// encodeMarker will encode a uuid and return it as a marker.
// uuid cannot contain '[', ':' or ','.
func encodeMarker(marker, uuid string) string {
if uuid == "" {
return marker
}
if strings.ContainsAny(uuid, "[:,") {
logger.LogIf(context.Background(), fmt.Errorf("encodeMarker: uuid %s contained invalid characters", uuid))
}
return fmt.Sprintf("%s[minio_cache:%s,id:%s]", marker, markerTagVersion, uuid)
}