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// Copyright 2024 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package os
import (
"internal/poll"
"io"
)
var pollCopyFileRange = poll.CopyFileRange
func (f *File) writeTo(w io.Writer) (written int64, handled bool, err error) {
return 0, false, nil
}
func (f *File) readFrom(r io.Reader) (written int64, handled bool, err error) {
// copy_file_range(2) doesn't support destinations opened with
// O_APPEND, so don't bother to try zero-copy with these system calls.
//
// Visit https://man.freebsd.org/cgi/man.cgi?copy_file_range(2)#ERRORS for details.
if f.appendMode {
return 0, false, nil
}
var (
remain int64
lr *io.LimitedReader
)
if lr, r, remain = tryLimitedReader(r); remain <= 0 {
return 0, true, nil
}
var src *File
switch v := r.(type) {
case *File:
src = v
case fileWithoutWriteTo:
src = v.File
default:
return 0, false, nil
}
if src.checkValid("ReadFrom") != nil {
// Avoid returning the error as we report handled as false,
// leave further error handling as the responsibility of the caller.
return 0, false, nil
}
written, handled, err = pollCopyFileRange(&f.pfd, &src.pfd, remain)
if lr != nil {
lr.N -= written
}
return written, handled, wrapSyscallError("copy_file_range", err)
}
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