support multi-module (#4)

* add multimodule
* re-package modules

server/internal/repo/repo.go

@@ -0,0 +1,90 @@
+package repo
+
+import (
+	"encoding"
+	"errors"
+
+	e "galaxy/error"
+
+	"github.com/iliadenisov/galaxy/server/internal/repo/fs"
+)
+
+func NewStorageError(err error) error {
+	return e.NewRepoError(err)
+}
+
+func NewGameNotInitializedError() error {
+	return e.NewGameNotInitializedError()
+}
+
+func NewReportNotFoundError() error {
+	return e.NewReportNotFoundError()
+}
+
+func NewStateError(msg string) error {
+	return e.NewGameStateError(msg)
+}
+
+type Storage interface {
+	Lock() (func() error, error)
+	Exists(string) (bool, error)
+	Write(string, encoding.BinaryMarshaler) error
+	WriteSafe(string, encoding.BinaryMarshaler) error
+	Read(string, encoding.BinaryUnmarshaler) error
+	ReadSafe(string, encoding.BinaryUnmarshaler) error
+}
+
+type repo struct {
+	s       Storage
+	release func() error
+}
+
+func NewRepo(s Storage) (*repo, error) {
+	r := &repo{
+		s: s,
+	}
+	return r, nil
+}
+
+func NewFileRepo(path string) (*repo, error) {
+	s, err := fs.NewFileStorage(path)
+	if err != nil {
+		return nil, err
+	}
+	return NewRepo(s)
+}
+
+func (r *repo) Lock() (err error) {
+	if r.s == nil {
+		return errors.New("storage is closed")
+	}
+	if r.release != nil {
+		return errors.New("storage already locked")
+	}
+	r.release, err = r.s.Lock()
+	if err != nil {
+		r.close()
+		return
+	}
+	return nil
+}
+
+func (r *repo) Release() (err error) {
+	if r.s == nil {
+		return errors.New("storage is closed")
+	}
+	if r.release == nil {
+		return errors.New("storage was never locked")
+	}
+	err = r.release()
+	if err != nil {
+		return
+	}
+	r.close()
+	return nil
+}
+
+func (r *repo) close() {
+	r.release = nil
+	r.s = nil
+}