rclone/vendor/github.com/hanwen/go-fuse/v2/fuse/read.go

76 lines
1.4 KiB
Go

// Copyright 2016 the Go-FUSE 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 fuse
import (
"io"
"syscall"
)
// ReadResultData is the read return for returning bytes directly.
type readResultData struct {
// Raw bytes for the read.
Data []byte
}
func (r *readResultData) Size() int {
return len(r.Data)
}
func (r *readResultData) Done() {
}
func (r *readResultData) Bytes(buf []byte) ([]byte, Status) {
return r.Data, OK
}
func ReadResultData(b []byte) ReadResult {
return &readResultData{b}
}
func ReadResultFd(fd uintptr, off int64, sz int) ReadResult {
return &readResultFd{fd, off, sz}
}
// ReadResultFd is the read return for zero-copy file data.
type readResultFd struct {
// Splice from the following file.
Fd uintptr
// Offset within Fd, or -1 to use current offset.
Off int64
// Size of data to be loaded. Actual data available may be
// less at the EOF.
Sz int
}
// Reads raw bytes from file descriptor if necessary, using the passed
// buffer as storage.
func (r *readResultFd) Bytes(buf []byte) ([]byte, Status) {
sz := r.Sz
if len(buf) < sz {
sz = len(buf)
}
n, err := syscall.Pread(int(r.Fd), buf[:sz], r.Off)
if err == io.EOF {
err = nil
}
if n < 0 {
n = 0
}
return buf[:n], ToStatus(err)
}
func (r *readResultFd) Size() int {
return r.Sz
}
func (r *readResultFd) Done() {
}