-
Notifications
You must be signed in to change notification settings - Fork 7
/
tree.go
93 lines (84 loc) · 2.57 KB
/
tree.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
// Copyright 2022 Google LLC
//
// 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 snapshot
import (
"encoding/base64"
"fmt"
"path/filepath"
"sort"
"strings"
)
// Path represents the filesystem path of a file.
//
// This can be either an absolute or relative path.
type Path string
// Join returns the path corresponding to joining this path with the supplied child path.
func (p Path) Join(child Path) Path {
return Path(filepath.Join(string(p), string(child)))
}
func (p Path) encode() string {
return base64.RawStdEncoding.EncodeToString([]byte(p))
}
func decodePath(encoded string) (Path, error) {
decoded, err := base64.RawStdEncoding.DecodeString(encoded)
if err != nil {
return Path(""), fmt.Errorf("failure decoding the encoded path string %q: %v", encoded, err)
}
return Path(decoded), nil
}
// Tree represents the contents of a directory.
//
// The keys are relative paths of the directory children, and the values
// are the hashes of each child's latest snapshot.
type Tree map[Path]*Hash
// String implements the `fmt.Stringer` interface.
//
// The resulting value is suitable for serialization.
func (t Tree) String() string {
var lines []string
for p, h := range t {
if h != nil {
line := p.encode() + " " + h.String()
lines = append(lines, line)
}
}
sort.Strings(lines)
return strings.Join(lines, "\n")
}
// ParseTree parses a `Tree` object from its encoded form.
//
// The input string must match the form returned by the `Tree.String` method.
func ParseTree(encoded string) (Tree, error) {
t := make(Tree)
lines := strings.Split(encoded, "\n")
for _, line := range lines {
if len(line) == 0 {
continue
}
parts := strings.SplitN(line, " ", 2)
if len(parts) != 2 {
return nil, fmt.Errorf("malformed entry %q in encoded tree %q", line, encoded)
}
p, err := decodePath(parts[0])
if err != nil {
return nil, fmt.Errorf("failure parsing encoded path %q: %v", parts[0], err)
}
h, err := ParseHash(parts[1])
if err != nil {
return nil, fmt.Errorf("failure parsing encoded hash %q: %v", parts[1], err)
}
t[p] = h
}
return t, nil
}