mirror of
https://github.com/rclone/rclone.git
synced 2024-12-12 04:04:06 +08:00
36 lines
690 B
Go
36 lines
690 B
Go
// Copyright (C) 2019 Storj Labs, Inc.
|
|
// See LICENSE for copying information.
|
|
|
|
package readcloser
|
|
|
|
import "io"
|
|
|
|
// LazyReadCloser returns an ReadCloser that doesn't initialize the backing
|
|
// Reader until the first Read.
|
|
func LazyReadCloser(reader func() (io.ReadCloser, error)) io.ReadCloser {
|
|
return &lazyReadCloser{fn: reader}
|
|
}
|
|
|
|
type lazyReadCloser struct {
|
|
fn func() (io.ReadCloser, error)
|
|
r io.ReadCloser
|
|
}
|
|
|
|
func (l *lazyReadCloser) Read(p []byte) (n int, err error) {
|
|
if l.r == nil {
|
|
l.r, err = l.fn()
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
l.fn = nil
|
|
}
|
|
return l.r.Read(p)
|
|
}
|
|
|
|
func (l *lazyReadCloser) Close() error {
|
|
if l.r != nil {
|
|
return l.r.Close()
|
|
}
|
|
return nil
|
|
}
|