up3

server/world/mcdb/conf.go

@@ -0,0 +1,72 @@
+package mcdb
+
+import (
+	"fmt"
+	"log/slog"
+	"os"
+	"path/filepath"
+
+	"github.com/df-mc/dragonfly/server/world"
+	"github.com/df-mc/dragonfly/server/world/mcdb/leveldat"
+	"github.com/df-mc/goleveldb/leveldb"
+	"github.com/df-mc/goleveldb/leveldb/opt"
+)
+
+// Config holds the optional parameters of a DB.
+type Config struct {
+	// Log is the Logger that will be used to log errors and debug messages to.
+	// If set to nil, Log is set to slog.Default().
+	Log *slog.Logger
+	// LDBOptions holds LevelDB specific default options, such as the block size
+	// or compression used in the database.
+	LDBOptions *opt.Options
+
+	// Blocks is the BlockRegistry used for chunk decoding/encoding. If nil, world.DefaultBlockRegistry is used.
+	// When using a non-default registry, pass the same registry used by the World.
+	Blocks world.BlockRegistry
+}
+
+// Open creates a new DB reading and writing from/to files under the path
+// passed. If a world is present at the path, Open will parse its data and
+// initialise the world with it. If the data cannot be parsed, an error is
+// returned.
+func (conf Config) Open(dir string) (*DB, error) {
+	if conf.Log == nil {
+		conf.Log = slog.Default()
+	}
+	conf.Log = conf.Log.With("provider", "mcdb")
+	if conf.LDBOptions == nil {
+		conf.LDBOptions = new(opt.Options)
+	}
+	if conf.LDBOptions.BlockSize == 0 {
+		conf.LDBOptions.BlockSize = 16 * opt.KiB
+	}
+
+	_ = os.MkdirAll(filepath.Join(dir, "db"), 0777)
+
+	db := &DB{conf: conf, dir: dir, ldat: &leveldat.Data{}}
+	db.SetBlockRegistry(conf.Blocks)
+	if _, err := os.Stat(filepath.Join(dir, "level.dat")); os.IsNotExist(err) {
+		// A level.dat was not currently present for the world.
+		db.ldat.FillDefault()
+	} else {
+		ldat, err := leveldat.ReadFile(filepath.Join(dir, "level.dat"))
+		if err != nil {
+			return nil, fmt.Errorf("open db: read level.dat: %w", err)
+		}
+		ver := ldat.Ver()
+		if ver != leveldat.Version && ver >= 10 {
+			return nil, fmt.Errorf("open db: level.dat version %v is unsupported", ver)
+		}
+		if err = ldat.Unmarshal(db.ldat); err != nil {
+			return nil, fmt.Errorf("open db: unmarshal level.dat: %w", err)
+		}
+	}
+	db.set = db.ldat.Settings()
+	ldb, err := leveldb.OpenFile(filepath.Join(dir, "db"), conf.LDBOptions)
+	if err != nil {
+		return nil, fmt.Errorf("open db: leveldb: %w", err)
+	}
+	db.ldb = ldb
+	return db, nil
+}