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.
102 lines
2.7 KiB
102 lines
2.7 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 memory-only implementation of Filer.
|
|
|
|
package lldb // import "modernc.org/lldb"
|
|
|
|
import (
|
|
"fmt"
|
|
"io"
|
|
|
|
"modernc.org/internal/file"
|
|
)
|
|
|
|
var _ Filer = &MemFiler{}
|
|
|
|
// MemFiler is a memory backed Filer. It implements BeginUpdate, EndUpdate and
|
|
// Rollback as no-ops. MemFiler is not automatically persistent, but it has
|
|
// ReadFrom and WriteTo methods.
|
|
type MemFiler struct {
|
|
fi file.Interface
|
|
nest int
|
|
}
|
|
|
|
// NewMemFiler returns a new MemFiler.
|
|
func NewMemFiler() *MemFiler {
|
|
fi, err := file.OpenMem("")
|
|
if err != nil {
|
|
return nil
|
|
}
|
|
|
|
return &MemFiler{fi: fi}
|
|
}
|
|
|
|
// BeginUpdate implements Filer.
|
|
func (f *MemFiler) BeginUpdate() error {
|
|
f.nest++
|
|
return nil
|
|
}
|
|
|
|
// Close implements Filer.
|
|
func (f *MemFiler) Close() (err error) {
|
|
if f.nest != 0 {
|
|
return &ErrPERM{(f.Name() + ":Close")}
|
|
}
|
|
|
|
return f.fi.Close()
|
|
}
|
|
|
|
// EndUpdate implements Filer.
|
|
func (f *MemFiler) EndUpdate() (err error) {
|
|
if f.nest == 0 {
|
|
return &ErrPERM{(f.Name() + ": EndUpdate")}
|
|
}
|
|
|
|
f.nest--
|
|
return
|
|
}
|
|
|
|
// Name implements Filer.
|
|
func (f *MemFiler) Name() string { return fmt.Sprintf("%p.memfiler", f) }
|
|
|
|
// PunchHole implements Filer.
|
|
func (f *MemFiler) PunchHole(off, size int64) (err error) { return nil }
|
|
|
|
// ReadAt implements Filer.
|
|
func (f *MemFiler) ReadAt(b []byte, off int64) (n int, err error) { return f.fi.ReadAt(b, off) }
|
|
|
|
// ReadFrom is a helper to populate MemFiler's content from r. 'n' reports the
|
|
// number of bytes read from 'r'.
|
|
func (f *MemFiler) ReadFrom(r io.Reader) (n int64, err error) { return f.fi.ReadFrom(r) }
|
|
|
|
// Rollback implements Filer.
|
|
func (f *MemFiler) Rollback() (err error) { return nil }
|
|
|
|
// Size implements Filer.
|
|
func (f *MemFiler) Size() (int64, error) {
|
|
info, err := f.fi.Stat()
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
return info.Size(), nil
|
|
}
|
|
|
|
// Sync implements Filer.
|
|
func (f *MemFiler) Sync() error { return nil }
|
|
|
|
// Truncate implements Filer.
|
|
func (f *MemFiler) Truncate(size int64) (err error) { return f.fi.Truncate(size) }
|
|
|
|
// WriteAt implements Filer.
|
|
func (f *MemFiler) WriteAt(b []byte, off int64) (n int, err error) { return f.fi.WriteAt(b, off) }
|
|
|
|
// WriteTo is a helper to copy/persist MemFiler's content to w. If w is also
|
|
// an io.WriterAt then WriteTo may attempt to _not_ write any big, for some
|
|
// value of big, runs of zeros, i.e. it will attempt to punch holes, where
|
|
// possible, in `w` if that happens to be a freshly created or to zero length
|
|
// truncated OS file. 'n' reports the number of bytes written to 'w'.
|
|
func (f *MemFiler) WriteTo(w io.Writer) (n int64, err error) { return f.fi.WriteTo(w) }
|