mirror of
https://github.com/octoleo/syncthing.git
synced 2024-12-23 11:28:59 +00:00
49 lines
1.3 KiB
Go
49 lines
1.3 KiB
Go
// Copyright (C) 2019 The Syncthing Authors.
|
|
//
|
|
// This Source Code Form is subject to the terms of the Mozilla Public
|
|
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
|
|
// You can obtain one at https://mozilla.org/MPL/2.0/.
|
|
|
|
//go:build linux
|
|
// +build linux
|
|
|
|
package fs
|
|
|
|
import (
|
|
"io"
|
|
"syscall"
|
|
|
|
"golang.org/x/sys/unix"
|
|
)
|
|
|
|
func init() {
|
|
registerCopyRangeImplementation(CopyRangeMethodCopyFileRange, copyRangeImplementationForBasicFile(copyRangeCopyFileRange))
|
|
}
|
|
|
|
func copyRangeCopyFileRange(src, dst basicFile, srcOffset, dstOffset, size int64) error {
|
|
for size > 0 {
|
|
// From MAN page:
|
|
//
|
|
// If off_in is not NULL, then off_in must point to a buffer that
|
|
// specifies the starting offset where bytes from fd_in will be read.
|
|
// The file offset of fd_in is not changed, but off_in is adjusted
|
|
// appropriately.
|
|
//
|
|
// Also, even if explicitly not stated, the same is true for dstOffset
|
|
n, err := withFileDescriptors(src, dst, func(srcFd, dstFd uintptr) (int, error) {
|
|
return unix.CopyFileRange(int(srcFd), &srcOffset, int(dstFd), &dstOffset, int(size), 0)
|
|
})
|
|
if n == 0 && err == nil {
|
|
return io.ErrUnexpectedEOF
|
|
}
|
|
if err != nil && err != syscall.EAGAIN {
|
|
return err
|
|
}
|
|
// Handle case where err == EAGAIN and n == -1 (it's not clear if that can happen)
|
|
if n > 0 {
|
|
size -= int64(n)
|
|
}
|
|
}
|
|
return nil
|
|
}
|