mirror of https://github.com/docker/cli.git
30 lines
602 B
Go
30 lines
602 B
Go
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package store
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import (
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"errors"
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"io"
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)
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// LimitedReader is a fork of io.LimitedReader to override Read.
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type LimitedReader struct {
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R io.Reader
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N int64 // max bytes remaining
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}
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// Read is a fork of io.LimitedReader.Read that returns an error when limit exceeded.
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func (l *LimitedReader) Read(p []byte) (n int, err error) {
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if l.N < 0 {
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return 0, errors.New("read exceeds the defined limit")
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}
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if l.N == 0 {
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return 0, io.EOF
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}
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// have to cap N + 1 otherwise we won't hit limit err
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if int64(len(p)) > l.N+1 {
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p = p[0 : l.N+1]
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}
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n, err = l.R.Read(p)
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l.N -= int64(n)
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return n, err
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}
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