You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
100 lines
2.6 KiB
100 lines
2.6 KiB
// 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.
|
|
|
|
// A basic os.File backed Filer.
|
|
|
|
package lldb // import "modernc.org/lldb"
|
|
|
|
import (
|
|
"os"
|
|
|
|
"modernc.org/internal/file"
|
|
)
|
|
|
|
var _ Filer = &SimpleFileFiler{}
|
|
|
|
// SimpleFileFiler is an os.File backed Filer intended for use where structural
|
|
// consistency can be reached by other means (SimpleFileFiler is for example
|
|
// wrapped in eg. an RollbackFiler or ACIDFiler0) or where persistence is not
|
|
// required (temporary/working data sets).
|
|
//
|
|
// SimpleFileFiler is the most simple os.File backed Filer implementation as it
|
|
// does not really implement BeginUpdate and EndUpdate/Rollback in any way
|
|
// which would protect the structural integrity of data. If misused e.g. as a
|
|
// real database storage w/o other measures, it can easily cause data loss
|
|
// when, for example, a power outage occurs or the updating process terminates
|
|
// abruptly.
|
|
type SimpleFileFiler struct {
|
|
fi file.Interface
|
|
name string
|
|
nest int
|
|
}
|
|
|
|
// NewSimpleFileFiler returns a new SimpleFileFiler.
|
|
func NewSimpleFileFiler(f *os.File) *SimpleFileFiler {
|
|
fi, err := file.Open(f)
|
|
if err != nil {
|
|
return nil
|
|
}
|
|
|
|
sf := &SimpleFileFiler{fi: fi, name: f.Name()}
|
|
return sf
|
|
}
|
|
|
|
// BeginUpdate implements Filer.
|
|
func (f *SimpleFileFiler) BeginUpdate() error {
|
|
f.nest++
|
|
return nil
|
|
}
|
|
|
|
// Close implements Filer.
|
|
func (f *SimpleFileFiler) Close() (err error) {
|
|
if f.nest != 0 {
|
|
return &ErrPERM{(f.Name() + ":Close")}
|
|
}
|
|
|
|
return f.fi.Close()
|
|
}
|
|
|
|
// EndUpdate implements Filer.
|
|
func (f *SimpleFileFiler) EndUpdate() (err error) {
|
|
if f.nest == 0 {
|
|
return &ErrPERM{(f.Name() + ":EndUpdate")}
|
|
}
|
|
|
|
f.nest--
|
|
return
|
|
}
|
|
|
|
// Name implements Filer.
|
|
func (f *SimpleFileFiler) Name() string { return f.name }
|
|
|
|
// PunchHole implements Filer.
|
|
func (f *SimpleFileFiler) PunchHole(off, size int64) (err error) { return nil }
|
|
|
|
// ReadAt implements Filer.
|
|
func (f *SimpleFileFiler) ReadAt(b []byte, off int64) (n int, err error) { return f.fi.ReadAt(b, off) }
|
|
|
|
// Rollback implements Filer.
|
|
func (f *SimpleFileFiler) Rollback() (err error) { return nil }
|
|
|
|
// Size implements Filer.
|
|
func (f *SimpleFileFiler) Size() (int64, error) {
|
|
info, err := f.fi.Stat()
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
return info.Size(), nil
|
|
}
|
|
|
|
// Sync implements Filer.
|
|
func (f *SimpleFileFiler) Sync() error { return f.fi.Sync() }
|
|
|
|
// Truncate implements Filer.
|
|
func (f *SimpleFileFiler) Truncate(size int64) (err error) { return f.fi.Truncate(size) }
|
|
|
|
// WriteAt implements Filer.
|
|
func (f *SimpleFileFiler) WriteAt(b []byte, off int64) (n int, err error) { return f.fi.WriteAt(b, off) }
|