Use constants for SHARDING and _README file names.

flatfs.go

@@ -43,7 +43,7 @@ type ShardFunc func(string) string
 var (
 	ErrDatastoreExists       = errors.New("datastore already exist")
 	ErrDatastoreDoesNotExist = errors.New("datastore directory does not exist")
-	ErrShardingFileMissing   = errors.New("SHARDING file not found in datastore")
+	ErrShardingFileMissing   = fmt.Errorf("%s file not found in datastore", SHARDING_FN)
 )
 
 const IPFS_DEF_SHARD = "/repo/flatfs/shard/v1/next-to-last/2"
@@ -68,7 +68,7 @@ func Create(path string, funStr string) error {
 			return err
 		}
 		if !isEmpty {
-			return fmt.Errorf("directory missing SHARDING file: %s", path)
+			return fmt.Errorf("directory missing %s file: %s", SHARDING_FN, path)
 		}
 
 		err = WriteShardFunc(path, fun)

flatfs_test.go

@@ -183,9 +183,9 @@ func testStorage(p *params, t *testing.T) {
 			return err
 		}
 		switch path {
-		case ".", "..", "SHARDING":
+		case ".", "..", flatfs.SHARDING_FN:
 			// ignore
-		case "_README":
+		case flatfs.README_FN:
 			_, err := ioutil.ReadFile(absPath)
 			if err != nil {
 				t.Error("could not read _README file")
@@ -487,7 +487,7 @@ func TestNoCluster(t *testing.T) {
 	tolerance := math.Floor(idealFilesPerDir * 0.20)
 	count := 0
 	for _, dir := range dirs {
-		if dir.Name() == "SHARDING" {
+		if dir.Name() == flatfs.SHARDING_FN || dir.Name() == flatfs.README_FN {
 			continue
 		}
 		count += 1

shard.go

@@ -16,6 +16,8 @@ type ShardIdV1 struct {
 }
 
 const PREFIX = "/repo/flatfs/shard/"
+const SHARDING_FN = "SHARDING"
+const README_FN = "README"
 
 func (f *ShardIdV1) String() string {
 	return fmt.Sprintf("%sv1/%s/%d", PREFIX, f.funName, f.param)
@@ -72,7 +74,7 @@ func ParseShardFunc(str string) (*ShardIdV1, error) {
 }
 
 func ReadShardFunc(dir string) (*ShardIdV1, error) {
-	buf, err := ioutil.ReadFile(filepath.Join(dir, "SHARDING"))
+	buf, err := ioutil.ReadFile(filepath.Join(dir, SHARDING_FN))
 	if os.IsNotExist(err) {
 		return nil, ErrShardingFileMissing
 	} else if err != nil {
@@ -82,7 +84,7 @@ func ReadShardFunc(dir string) (*ShardIdV1, error) {
 }
 
 func WriteShardFunc(dir string, id *ShardIdV1) error {
-	file, err := os.Create(filepath.Join(dir, "SHARDING"))
+	file, err := os.Create(filepath.Join(dir, SHARDING_FN))
 	if err != nil {
 		return err
 	}
@@ -97,7 +99,7 @@ func WriteShardFunc(dir string, id *ShardIdV1) error {
 
 func WriteReadme(dir string, id *ShardIdV1) error {
 	if id.String() == IPFS_DEF_SHARD {
-		err := ioutil.WriteFile(filepath.Join(dir, "_README"), []byte(README_IPFS_DEF_SHARD), 0444)
+		err := ioutil.WriteFile(filepath.Join(dir, README_FN), []byte(README_IPFS_DEF_SHARD), 0444)
 		if err != nil {
 			return err
 		}