Initial commit

vendor/github.com/cockroachdb/pebble/sstable/format.go

@@ -0,0 +1,91 @@
+// Copyright 2022 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 sstable
+
+import (
+	"github.com/cockroachdb/errors"
+	"github.com/cockroachdb/pebble/internal/base"
+)
+
+// TableFormat specifies the format version for sstables. The legacy LevelDB
+// format is format version 1.
+type TableFormat uint32
+
+// The available table formats, representing the tuple (magic number, version
+// number). Note that these values are not (and should not) be serialized to
+// disk. The ordering should follow the order the versions were introduced to
+// Pebble (i.e. the history is linear).
+const (
+	TableFormatUnspecified TableFormat = iota
+	TableFormatLevelDB
+	TableFormatRocksDBv2
+	TableFormatPebblev1 // Block properties.
+	TableFormatPebblev2 // Range keys.
+
+	TableFormatMax = TableFormatPebblev2
+)
+
+// ParseTableFormat parses the given magic bytes and version into its
+// corresponding internal TableFormat.
+func ParseTableFormat(magic []byte, version uint32) (TableFormat, error) {
+	switch string(magic) {
+	case levelDBMagic:
+		return TableFormatLevelDB, nil
+	case rocksDBMagic:
+		if version != rocksDBFormatVersion2 {
+			return TableFormatUnspecified, base.CorruptionErrorf(
+				"pebble/table: unsupported rocksdb format version %d", errors.Safe(version),
+			)
+		}
+		return TableFormatRocksDBv2, nil
+	case pebbleDBMagic:
+		switch version {
+		case 1:
+			return TableFormatPebblev1, nil
+		case 2:
+			return TableFormatPebblev2, nil
+		default:
+			return TableFormatUnspecified, base.CorruptionErrorf(
+				"pebble/table: unsupported pebble format version %d", errors.Safe(version),
+			)
+		}
+	default:
+		return TableFormatUnspecified, base.CorruptionErrorf(
+			"pebble/table: invalid table (bad magic number)",
+		)
+	}
+}
+
+// AsTuple returns the TableFormat's (Magic String, Version) tuple.
+func (f TableFormat) AsTuple() (string, uint32) {
+	switch f {
+	case TableFormatLevelDB:
+		return levelDBMagic, 0
+	case TableFormatRocksDBv2:
+		return rocksDBMagic, 2
+	case TableFormatPebblev1:
+		return pebbleDBMagic, 1
+	case TableFormatPebblev2:
+		return pebbleDBMagic, 2
+	default:
+		panic("sstable: unknown table format version tuple")
+	}
+}
+
+// String returns the TableFormat (Magic String,Version) tuple.
+func (f TableFormat) String() string {
+	switch f {
+	case TableFormatLevelDB:
+		return "(LevelDB)"
+	case TableFormatRocksDBv2:
+		return "(RocksDB,v2)"
+	case TableFormatPebblev1:
+		return "(Pebble,v1)"
+	case TableFormatPebblev2:
+		return "(Pebble,v2)"
+	default:
+		panic("sstable: unknown table format version tuple")
+	}
+}