55 lines
1.1 KiB
Go
55 lines
1.1 KiB
Go
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package rifs
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import (
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"fmt"
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"io"
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)
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const (
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defaultCopyBufferSize = 1024 * 1024
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)
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// GracefulCopy willcopy while enduring lesser normal issues.
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//
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// - We'll ignore EOF if the read byte-count is more than zero. Only an EOF when
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// zero bytes were read will terminate the loop.
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//
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// - Ignore short-writes. If less bytes were written than the bytes that were
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// given, we'll keep trying until done.
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func GracefulCopy(w io.Writer, r io.Reader, buffer []byte) (copyCount int, err error) {
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if buffer == nil {
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buffer = make([]byte, defaultCopyBufferSize)
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}
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for {
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readCount, err := r.Read(buffer)
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if err != nil {
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if err != io.EOF {
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err = fmt.Errorf("read error: %s", err.Error())
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return 0, err
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}
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// Only break on EOF if no bytes were actually read.
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if readCount == 0 {
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break
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}
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}
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writeBuffer := buffer[:readCount]
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for len(writeBuffer) > 0 {
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writtenCount, err := w.Write(writeBuffer)
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if err != nil {
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err = fmt.Errorf("write error: %s", err.Error())
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return 0, err
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}
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writeBuffer = writeBuffer[writtenCount:]
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}
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copyCount += readCount
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}
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return copyCount, nil
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}
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