54 lines
1.2 KiB
Go
54 lines
1.2 KiB
Go
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/*
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Copyright 2015 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package limitwriter
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import (
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"errors"
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"io"
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)
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// New creates a writer that is limited to writing at most n bytes to w. This writer is not
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// thread safe.
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func New(w io.Writer, n int64) io.Writer {
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return &limitWriter{
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w: w,
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n: n,
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}
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}
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// ErrMaximumWrite is returned when all bytes have been written.
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var ErrMaximumWrite = errors.New("maximum write")
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type limitWriter struct {
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w io.Writer
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n int64
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}
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func (w *limitWriter) Write(p []byte) (n int, err error) {
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if int64(len(p)) > w.n {
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p = p[:w.n]
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}
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if w.n > 0 {
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n, err = w.w.Write(p)
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w.n -= int64(n)
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}
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if w.n == 0 {
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err = ErrMaximumWrite
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}
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return
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}
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