Repository navigation
Expand file tree
/
Copy pathfingerprint.go
More file actions
54 lines (51 loc) · 1.46 KB
/
Copy pathfingerprint.go
File metadata and controls
54 lines (51 loc) · 1.46 KB
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
package fs
import (
"context"
"fmt"
"strings"
"github.com/rclone/rclone/fs/hash"
)
// Fingerprint produces a unique-ish string for an object.
//
// This is for detecting whether an object has changed since we last
// saw it, not for checking object identity between two different
// remotes - operations.Equal should be used for that.
//
// If fast is set then Fingerprint will only include attributes where
// usually another operation is not required to fetch them. For
// example if fast is set then this won't include hashes on the local
// backend.
func Fingerprint(ctx context.Context, o ObjectInfo, fast bool) string {
var (
out strings.Builder
f = o.Fs()
features = f.Features()
)
fmt.Fprintf(&out, "%d", o.Size())
// Whether we want to do a slow operation or not
//
// fast true false true false
// opIsSlow true true false false
// do Op false true true true
//
// If !fast (slow) do the operation or if !OpIsSlow ==
// OpIsFast do the operation.
//
// Eg don't do this for S3 where modtimes are expensive
if !fast || !features.SlowModTime {
if f.Precision() != ModTimeNotSupported {
fmt.Fprintf(&out, ",%v", o.ModTime(ctx).UTC())
}
}
// Eg don't do this for SFTP/local where hashes are expensive?
if !fast || !features.SlowHash {
hashType := f.Hashes().GetOne()
if hashType != hash.None {
hash, err := o.Hash(ctx, hashType)
if err == nil {
fmt.Fprintf(&out, ",%v", hash)
}
}
}
return out.String()
}