46 lines
1 KiB
Go
46 lines
1 KiB
Go
// Copyright 2020 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package os
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import (
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"internal/poll"
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"io"
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)
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var pollCopyFileRange = poll.CopyFileRange
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func (f *File) readFrom(r io.Reader) (written int64, handled bool, err error) {
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// copy_file_range(2) does not support destinations opened with
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// O_APPEND, so don't even try.
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if f.appendMode {
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return 0, false, nil
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}
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remain := int64(1 << 62)
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lr, ok := r.(*io.LimitedReader)
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if ok {
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remain, r = lr.N, lr.R
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if remain <= 0 {
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return 0, true, nil
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}
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}
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src, ok := r.(*File)
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if !ok {
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return 0, false, nil
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}
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if src.checkValid("ReadFrom") != nil {
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// Avoid returning the error as we report handled as false,
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// leave further error handling as the responsibility of the caller.
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return 0, false, nil
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}
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written, handled, err = pollCopyFileRange(&f.pfd, &src.pfd, remain)
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if lr != nil {
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lr.N -= written
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}
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return written, handled, NewSyscallError("copy_file_range", err)
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}
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