up3

server/world/provider.go

@@ -0,0 +1,60 @@
+package world
+
+import (
+	"github.com/df-mc/dragonfly/server/block/cube"
+	"github.com/df-mc/dragonfly/server/world/chunk"
+	"github.com/df-mc/goleveldb/leveldb"
+	"github.com/google/uuid"
+	"io"
+)
+
+// Provider represents a value that may provide world data to a World value. It usually does the reading and
+// writing of the world data so that the World may use it.
+type Provider interface {
+	io.Closer
+	// Settings loads the settings for a World and returns them.
+	Settings() *Settings
+	// SaveSettings saves the settings of a World.
+	SaveSettings(*Settings)
+
+	// LoadPlayerSpawnPosition loads the player spawn point if found, otherwise an error will be returned.
+	LoadPlayerSpawnPosition(uuid uuid.UUID) (pos cube.Pos, exists bool, err error)
+	// SavePlayerSpawnPosition saves the player spawn point. In vanilla, this can be done with beds in the overworld
+	// or respawn anchors in the nether.
+	SavePlayerSpawnPosition(uuid uuid.UUID, pos cube.Pos) error
+	// LoadColumn reads a world.Column from the DB at a position and dimension
+	// in the DB. If no column at that position exists, errors.Is(err,
+	// leveldb.ErrNotFound) equals true.
+	LoadColumn(pos ChunkPos, dim Dimension) (*chunk.Column, error)
+	// StoreColumn stores a world.Column at a position and dimension in the DB.
+	// An error is returned if storing was unsuccessful.
+	StoreColumn(pos ChunkPos, dim Dimension, col *chunk.Column) error
+}
+
+// Compile time check to make sure NopProvider implements Provider.
+var _ Provider = (*NopProvider)(nil)
+
+// NopProvider implements a Provider that does not perform any disk I/O. It generates values on the run and
+// dynamically, instead of reading and writing data, and otherwise returns empty values. A Settings struct can be passed
+// to initialise a world with specific settings. Since Settings is a pointer, using the same NopProvider for multiple
+// worlds means those worlds will share the same settings.
+type NopProvider struct {
+	Set *Settings
+}
+
+func (n NopProvider) Settings() *Settings {
+	if n.Set == nil {
+		return defaultSettings()
+	}
+	return n.Set
+}
+func (NopProvider) SaveSettings(*Settings) {}
+func (NopProvider) LoadColumn(ChunkPos, Dimension) (*chunk.Column, error) {
+	return nil, leveldb.ErrNotFound
+}
+func (NopProvider) StoreColumn(ChunkPos, Dimension, *chunk.Column) error { return nil }
+func (NopProvider) LoadPlayerSpawnPosition(uuid.UUID) (cube.Pos, bool, error) {
+	return cube.Pos{}, false, nil
+}
+func (NopProvider) SavePlayerSpawnPosition(uuid.UUID, cube.Pos) error { return nil }
+func (NopProvider) Close() error                                      { return nil }