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// Copyright 2014 The lldb 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 lldb
import (
"io"
"os"
"github.com/cznic/mathutil"
)
var _ Filer = (*OSFiler)(nil)
// OSFile is an os.File like minimal set of methods allowing to construct a
// Filer.
type OSFile interface {
Name() string
Stat() (fi os.FileInfo, err error)
Sync() (err error)
Truncate(size int64) (err error)
io.Closer
io.Reader
io.ReaderAt
io.Seeker
io.Writer
io.WriterAt
}
// OSFiler is like a SimpleFileFiler but based on an OSFile.
type OSFiler struct {
f OSFile
nest int
size int64 // not set if < 0
}
// NewOSFiler returns a Filer from an OSFile. This Filer is like the
// SimpleFileFiler, it does not implement the transaction related methods.
func NewOSFiler(f OSFile) (r *OSFiler) {
return &OSFiler{
f: f,
size: -1,
}
}
// BeginUpdate implements Filer.
func (f *OSFiler) BeginUpdate() (err error) {
f.nest++
return nil
}
// Close implements Filer.
func (f *OSFiler) Close() (err error) {
if f.nest != 0 {
return &ErrPERM{(f.Name() + ":Close")}
}
return f.f.Close()
}
// EndUpdate implements Filer.
func (f *OSFiler) EndUpdate() (err error) {
if f.nest == 0 {
return &ErrPERM{(f.Name() + ":EndUpdate")}
}
f.nest--
return
}
// Name implements Filer.
func (f *OSFiler) Name() string {
return f.f.Name()
}
// PunchHole implements Filer.
func (f *OSFiler) PunchHole(off, size int64) (err error) {
return
}
// ReadAt implements Filer.
func (f *OSFiler) ReadAt(b []byte, off int64) (n int, err error) {
return f.f.ReadAt(b, off)
}
// Rollback implements Filer.
func (f *OSFiler) Rollback() (err error) { return }
// Size implements Filer.
func (f *OSFiler) Size() (n int64, err error) {
if f.size < 0 { // boot
fi, err := f.f.Stat()
if err != nil {
return 0, err
}
f.size = fi.Size()
}
return f.size, nil
}
// Sync implements Filer.
func (f *OSFiler) Sync() (err error) {
return f.f.Sync()
}
// Truncate implements Filer.
func (f *OSFiler) Truncate(size int64) (err error) {
if size < 0 {
return &ErrINVAL{"Truncate size", size}
}
f.size = size
return f.f.Truncate(size)
}
// WriteAt implements Filer.
func (f *OSFiler) WriteAt(b []byte, off int64) (n int, err error) {
if f.size < 0 { // boot
fi, err := os.Stat(f.f.Name())
if err != nil {
return 0, err
}
f.size = fi.Size()
}
f.size = mathutil.MaxInt64(f.size, int64(len(b))+off)
return f.f.WriteAt(b, off)
}
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