ceremonyclient/pebble/objstorage/remote/localfs.go

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2024-01-03 07:31:42 +00:00
// Copyright 2023 The LevelDB-Go and Pebble 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 remote
import (
"context"
"io"
"os"
"path"
"github.com/cockroachdb/pebble/vfs"
)
// NewLocalFS returns a vfs-backed implementation of the remote.Storage
// interface (for testing). All objects will be stored at the directory
// dirname.
func NewLocalFS(dirname string, fs vfs.FS) Storage {
store := &localFSStore{
dirname: dirname,
vfs: fs,
}
return store
}
// localFSStore is a vfs-backed implementation of the remote.Storage
// interface (for testing).
type localFSStore struct {
dirname string
vfs vfs.FS
}
var _ Storage = (*localFSStore)(nil)
// Close is part of the remote.Storage interface.
func (s *localFSStore) Close() error {
*s = localFSStore{}
return nil
}
// ReadObject is part of the remote.Storage interface.
func (s *localFSStore) ReadObject(
ctx context.Context, objName string,
) (_ ObjectReader, objSize int64, _ error) {
f, err := s.vfs.Open(path.Join(s.dirname, objName))
if err != nil {
return nil, 0, err
}
stat, err := f.Stat()
if err != nil {
return nil, 0, err
}
return &localFSReader{f}, stat.Size(), nil
}
type localFSReader struct {
file vfs.File
}
var _ ObjectReader = (*localFSReader)(nil)
// ReadAt is part of the shared.ObjectReader interface.
func (r *localFSReader) ReadAt(_ context.Context, p []byte, offset int64) error {
n, err := r.file.ReadAt(p, offset)
// https://pkg.go.dev/io#ReaderAt
if err == io.EOF && n == len(p) {
return nil
}
return err
}
// Close is part of the shared.ObjectReader interface.
func (r *localFSReader) Close() error {
r.file.Close()
r.file = nil
return nil
}
// CreateObject is part of the remote.Storage interface.
func (s *localFSStore) CreateObject(objName string) (io.WriteCloser, error) {
file, err := s.vfs.Create(path.Join(s.dirname, objName))
return file, err
}
// List is part of the remote.Storage interface.
func (s *localFSStore) List(prefix, delimiter string) ([]string, error) {
// TODO(josh): For the intended use case of localfs.go of running 'pebble bench',
// List can always return <nil, nil>, since this indicates a file has only one ref,
// and since `pebble bench` implies running in a single-pebble-instance context.
// https://github.com/cockroachdb/pebble/blob/a9a079d4fb6bf4a9ebc52e4d83a76ad4cbf676cb/objstorage/objstorageprovider/shared.go#L292
return nil, nil
}
// Delete is part of the remote.Storage interface.
func (s *localFSStore) Delete(objName string) error {
return s.vfs.Remove(path.Join(s.dirname, objName))
}
// Size is part of the remote.Storage interface.
func (s *localFSStore) Size(objName string) (int64, error) {
f, err := s.vfs.Open(path.Join(s.dirname, objName))
if err != nil {
return 0, err
}
defer f.Close()
stat, err := f.Stat()
if err != nil {
return 0, err
}
return stat.Size(), nil
}
// IsNotExistError is part of the remote.Storage interface.
func (s *localFSStore) IsNotExistError(err error) bool {
return err == os.ErrNotExist
}