[WIP] Partial bot skeleton, non-functional though

vendor/github.com/cockroachdb/pebble/objstorage/vfs_writable.go

@@ -0,0 +1,64 @@
+// 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 objstorage
+
+import (
+	"bufio"
+
+	"github.com/cockroachdb/pebble/vfs"
+)
+
+// NewFileWritable returns a Writable that uses a file as underlying storage.
+func NewFileWritable(file vfs.File) Writable {
+	return newFileBufferedWritable(file)
+}
+
+type fileBufferedWritable struct {
+	file vfs.File
+	bw   *bufio.Writer
+}
+
+var _ Writable = (*fileBufferedWritable)(nil)
+
+func newFileBufferedWritable(file vfs.File) *fileBufferedWritable {
+	return &fileBufferedWritable{
+		file: file,
+		bw:   bufio.NewWriter(file),
+	}
+}
+
+// Write is part of the objstorage.Writable interface.
+func (w *fileBufferedWritable) Write(p []byte) error {
+	// Ignoring the length written since bufio.Writer.Write is guaranteed to
+	// return an error if the length written is < len(p).
+	_, err := w.bw.Write(p)
+	return err
+}
+
+// Finish is part of the objstorage.Writable interface.
+func (w *fileBufferedWritable) Finish() error {
+	err := w.bw.Flush()
+	if err == nil {
+		err = w.file.Sync()
+	}
+	err = firstError(err, w.file.Close())
+	w.bw = nil
+	w.file = nil
+	return err
+}
+
+// Abort is part of the objstorage.Writable interface.
+func (w *fileBufferedWritable) Abort() {
+	_ = w.file.Close()
+	w.bw = nil
+	w.file = nil
+}
+
+func firstError(err0, err1 error) error {
+	if err0 != nil {
+		return err0
+	}
+	return err1
+}