1 /* 2 Copyright The containerd Authors. 3 4 Licensed under the Apache License, Version 2.0 (the "License"); 5 you may not use this file except in compliance with the License. 6 You may obtain a copy of the License at 7 8 http://www.apache.org/licenses/LICENSE-2.0 9 10 Unless required by applicable law or agreed to in writing, software 11 distributed under the License is distributed on an "AS IS" BASIS, 12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 See the License for the specific language governing permissions and 14 limitations under the License. 15 */ 16 17 package reference 18 19 import ( 20 "sort" 21 ) 22 23 // Sort sorts string references preferring higher information references. 24 // 25 // The precedence is as follows: 26 // 27 // 1. [Named] + [Tagged] + [Digested] (e.g., "docker.io/library/busybox:latest@sha256:<digest>") 28 // 2. [Named] + [Tagged] (e.g., "docker.io/library/busybox:latest") 29 // 3. [Named] + [Digested] (e.g., "docker.io/library/busybo@sha256:<digest>") 30 // 4. [Named] (e.g., "docker.io/library/busybox") 31 // 5. [Digested] (e.g., "docker.io@sha256:<digest>") 32 // 6. Parse error 33 func Sort(references []string) []string { 34 var prefs []Reference 35 var bad []string 36 37 for _, ref := range references { 38 pref, err := ParseAnyReference(ref) 39 if err != nil { 40 bad = append(bad, ref) 41 } else { 42 prefs = append(prefs, pref) 43 } 44 } 45 sort.Slice(prefs, func(a, b int) bool { 46 ar := refRank(prefs[a]) 47 br := refRank(prefs[b]) 48 if ar == br { 49 return prefs[a].String() < prefs[b].String() 50 } 51 return ar < br 52 }) 53 sort.Strings(bad) 54 var refs []string 55 for _, pref := range prefs { 56 refs = append(refs, pref.String()) 57 } 58 return append(refs, bad...) 59 } 60 61 func refRank(ref Reference) uint8 { 62 if _, ok := ref.(Named); ok { 63 if _, ok = ref.(Tagged); ok { 64 if _, ok = ref.(Digested); ok { 65 return 1 66 } 67 return 2 68 } 69 if _, ok = ref.(Digested); ok { 70 return 3 71 } 72 return 4 73 } 74 return 5 75 } 76