2017-11-08 00:18:59 +01:00
|
|
|
/*
|
2018-02-24 00:07:21 +01:00
|
|
|
* Minio Cloud Storage, (C) 2017, 2018 Minio, Inc.
|
2017-11-08 00:18:59 +01:00
|
|
|
*
|
|
|
|
* 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 ioutil implements some I/O utility functions which are not covered
|
|
|
|
// by the standard library.
|
|
|
|
package ioutil
|
|
|
|
|
|
|
|
import (
|
|
|
|
"io"
|
2018-01-31 22:17:24 +01:00
|
|
|
|
|
|
|
humanize "github.com/dustin/go-humanize"
|
2017-11-08 00:18:59 +01:00
|
|
|
)
|
|
|
|
|
2018-01-31 22:17:24 +01:00
|
|
|
// defaultAppendBufferSize - Default buffer size for the AppendFile
|
|
|
|
const defaultAppendBufferSize = humanize.MiByte
|
|
|
|
|
2017-11-08 00:18:59 +01:00
|
|
|
// WriteOnCloser implements io.WriteCloser and always
|
|
|
|
// exectues at least one write operation if it is closed.
|
|
|
|
//
|
|
|
|
// This can be useful within the context of HTTP. At least
|
|
|
|
// one write operation must happen to send the HTTP headers
|
|
|
|
// to the peer.
|
|
|
|
type WriteOnCloser struct {
|
|
|
|
io.Writer
|
|
|
|
hasWritten bool
|
|
|
|
}
|
|
|
|
|
|
|
|
func (w *WriteOnCloser) Write(p []byte) (int, error) {
|
|
|
|
w.hasWritten = true
|
|
|
|
return w.Writer.Write(p)
|
|
|
|
}
|
|
|
|
|
|
|
|
// Close closes the WriteOnCloser. It behaves like io.Closer.
|
|
|
|
func (w *WriteOnCloser) Close() error {
|
|
|
|
if !w.hasWritten {
|
|
|
|
_, err := w.Write(nil)
|
|
|
|
if err != nil {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if closer, ok := w.Writer.(io.Closer); ok {
|
|
|
|
return closer.Close()
|
|
|
|
}
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
// HasWritten returns true if at least one write operation was performed.
|
|
|
|
func (w *WriteOnCloser) HasWritten() bool { return w.hasWritten }
|
|
|
|
|
|
|
|
// WriteOnClose takes an io.Writer and returns an ioutil.WriteOnCloser.
|
|
|
|
func WriteOnClose(w io.Writer) *WriteOnCloser {
|
|
|
|
return &WriteOnCloser{w, false}
|
|
|
|
}
|
2018-02-24 00:07:21 +01:00
|
|
|
|
|
|
|
// LimitWriter implements io.WriteCloser.
|
|
|
|
//
|
|
|
|
// This is implemented such that we want to restrict
|
|
|
|
// an enscapsulated writer upto a certain length
|
|
|
|
// and skip a certain number of bytes.
|
|
|
|
type LimitWriter struct {
|
|
|
|
io.Writer
|
|
|
|
skipBytes int64
|
|
|
|
wLimit int64
|
|
|
|
}
|
|
|
|
|
|
|
|
// Implements the io.Writer interface limiting upto
|
|
|
|
// configured length, also skips the first N bytes.
|
|
|
|
func (w *LimitWriter) Write(p []byte) (n int, err error) {
|
|
|
|
n = len(p)
|
|
|
|
var n1 int
|
|
|
|
if w.skipBytes > 0 {
|
|
|
|
if w.skipBytes >= int64(len(p)) {
|
|
|
|
w.skipBytes = w.skipBytes - int64(len(p))
|
|
|
|
return n, nil
|
|
|
|
}
|
|
|
|
p = p[w.skipBytes:]
|
|
|
|
w.skipBytes = 0
|
|
|
|
}
|
|
|
|
if w.wLimit == 0 {
|
|
|
|
return n, nil
|
|
|
|
}
|
|
|
|
if w.wLimit < int64(len(p)) {
|
|
|
|
n1, err = w.Writer.Write(p[:w.wLimit])
|
|
|
|
w.wLimit = w.wLimit - int64(n1)
|
|
|
|
return n, err
|
|
|
|
}
|
|
|
|
n1, err = w.Writer.Write(p)
|
|
|
|
w.wLimit = w.wLimit - int64(n1)
|
|
|
|
return n, err
|
|
|
|
}
|
|
|
|
|
|
|
|
// Close closes the LimitWriter. It behaves like io.Closer.
|
|
|
|
func (w *LimitWriter) Close() error {
|
|
|
|
if closer, ok := w.Writer.(io.Closer); ok {
|
|
|
|
return closer.Close()
|
|
|
|
}
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
// LimitedWriter takes an io.Writer and returns an ioutil.LimitWriter.
|
|
|
|
func LimitedWriter(w io.Writer, skipBytes int64, limit int64) *LimitWriter {
|
|
|
|
return &LimitWriter{w, skipBytes, limit}
|
|
|
|
}
|
2018-03-03 02:24:02 +01:00
|
|
|
|
|
|
|
type nopCloser struct {
|
|
|
|
io.Writer
|
|
|
|
}
|
|
|
|
|
|
|
|
func (nopCloser) Close() error { return nil }
|
|
|
|
|
|
|
|
// NopCloser returns a WriteCloser with a no-op Close method wrapping
|
|
|
|
// the provided Writer w.
|
|
|
|
func NopCloser(w io.Writer) io.WriteCloser {
|
|
|
|
return nopCloser{w}
|
|
|
|
}
|
2018-09-21 04:22:09 +02:00
|
|
|
|
|
|
|
// SkipReader skips a given number of bytes and then returns all
|
|
|
|
// remaining data.
|
|
|
|
type SkipReader struct {
|
|
|
|
io.Reader
|
|
|
|
|
|
|
|
skipCount int64
|
|
|
|
}
|
|
|
|
|
|
|
|
func (s *SkipReader) Read(p []byte) (int, error) {
|
|
|
|
l := int64(len(p))
|
|
|
|
if l == 0 {
|
|
|
|
return 0, nil
|
|
|
|
}
|
|
|
|
for s.skipCount > 0 {
|
|
|
|
if l > s.skipCount {
|
|
|
|
l = s.skipCount
|
|
|
|
}
|
|
|
|
n, err := s.Reader.Read(p[:l])
|
|
|
|
if err != nil {
|
|
|
|
return 0, err
|
|
|
|
}
|
|
|
|
s.skipCount -= int64(n)
|
|
|
|
}
|
|
|
|
return s.Reader.Read(p)
|
|
|
|
}
|
|
|
|
|
|
|
|
// NewSkipReader - creates a SkipReader
|
|
|
|
func NewSkipReader(r io.Reader, n int64) io.Reader {
|
|
|
|
return &SkipReader{r, n}
|
|
|
|
}
|