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
|
/*
* Minio Go Library for Amazon S3 Compatible Cloud Storage (C) 2015, 2016 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 minio
import "io"
// hookReader hooks additional reader in the source stream. It is
// useful for making progress bars. Second reader is appropriately
// notified about the exact number of bytes read from the primary
// source on each Read operation.
type hookReader struct {
source io.Reader
hook io.Reader
}
// Seek implements io.Seeker. Seeks source first, and if necessary
// seeks hook if Seek method is appropriately found.
func (hr *hookReader) Seek(offset int64, whence int) (n int64, err error) {
// Verify for source has embedded Seeker, use it.
sourceSeeker, ok := hr.source.(io.Seeker)
if ok {
return sourceSeeker.Seek(offset, whence)
}
// Verify if hook has embedded Seeker, use it.
hookSeeker, ok := hr.hook.(io.Seeker)
if ok {
return hookSeeker.Seek(offset, whence)
}
return n, nil
}
// Read implements io.Reader. Always reads from the source, the return
// value 'n' number of bytes are reported through the hook. Returns
// error for all non io.EOF conditions.
func (hr *hookReader) Read(b []byte) (n int, err error) {
n, err = hr.source.Read(b)
if err != nil && err != io.EOF {
return n, err
}
// Progress the hook with the total read bytes from the source.
if _, herr := hr.hook.Read(b[:n]); herr != nil {
if herr != io.EOF {
return n, herr
}
}
return n, err
}
// newHook returns a io.ReadSeeker which implements hookReader that
// reports the data read from the source to the hook.
func newHook(source, hook io.Reader) io.Reader {
if hook == nil {
return source
}
return &hookReader{source, hook}
}
|
