From b513597546f1f7958d1fc46288d791aa2cc89bee Mon Sep 17 00:00:00 2001
From: greatroar <61184462+greatroar@users.noreply.github.com>
Date: Sun, 16 Oct 2022 10:36:37 +0200
Subject: [PATCH] internal/restic: Make FileType a uint8 instead of a string

The string form was presumably useful before the introduction of
layouts, but right now it just makes call sequences and garbage
collection more expensive (the latter because every string contains
a pointer to be scanned).
---
 internal/restic/file.go      | 40 +++++++++++++++++++++++++-----------
 internal/restic/file_test.go | 30 +++++++++++++++++----------
 2 files changed, 47 insertions(+), 23 deletions(-)

diff --git a/internal/restic/file.go b/internal/restic/file.go
index d058a71c0..0e9f046ae 100644
--- a/internal/restic/file.go
+++ b/internal/restic/file.go
@@ -7,18 +7,38 @@ import (
 )
 
 // FileType is the type of a file in the backend.
-type FileType string
+type FileType uint8
 
 // These are the different data types a backend can store.
 const (
-	PackFile     FileType = "data" // use data, as packs are stored under /data in repo
-	KeyFile      FileType = "key"
-	LockFile     FileType = "lock"
-	SnapshotFile FileType = "snapshot"
-	IndexFile    FileType = "index"
-	ConfigFile   FileType = "config"
+	PackFile FileType = 1 + iota
+	KeyFile
+	LockFile
+	SnapshotFile
+	IndexFile
+	ConfigFile
 )
 
+func (t FileType) String() string {
+	s := "invalid"
+	switch t {
+	case PackFile:
+		// Spelled "data" instead of "pack" for historical reasons.
+		s = "data"
+	case KeyFile:
+		s = "key"
+	case LockFile:
+		s = "lock"
+	case SnapshotFile:
+		s = "snapshot"
+	case IndexFile:
+		s = "index"
+	case ConfigFile:
+		s = "config"
+	}
+	return s
+}
+
 // Handle is used to store and access data in a backend.
 type Handle struct {
 	Type              FileType
@@ -36,10 +56,6 @@ func (h Handle) String() string {
 
 // Valid returns an error if h is not valid.
 func (h Handle) Valid() error {
-	if h.Type == "" {
-		return errors.New("type is empty")
-	}
-
 	switch h.Type {
 	case PackFile:
 	case KeyFile:
@@ -48,7 +64,7 @@ func (h Handle) Valid() error {
 	case IndexFile:
 	case ConfigFile:
 	default:
-		return errors.Errorf("invalid Type %q", h.Type)
+		return errors.Errorf("invalid Type %d", h.Type)
 	}
 
 	if h.Type == ConfigFile {
diff --git a/internal/restic/file_test.go b/internal/restic/file_test.go
index 76f00baac..cc54c2924 100644
--- a/internal/restic/file_test.go
+++ b/internal/restic/file_test.go
@@ -1,20 +1,28 @@
 package restic
 
-import "testing"
+import (
+	"testing"
 
-var handleTests = []struct {
-	h     Handle
-	valid bool
-}{
-	{Handle{Name: "foo"}, false},
-	{Handle{Type: "foobar"}, false},
-	{Handle{Type: ConfigFile, Name: ""}, true},
-	{Handle{Type: PackFile, Name: ""}, false},
-	{Handle{Type: "", Name: "x"}, false},
-	{Handle{Type: LockFile, Name: "010203040506"}, true},
+	rtest "github.com/restic/restic/internal/test"
+)
+
+func TestHandleString(t *testing.T) {
+	rtest.Equals(t, "<data/foobar>", Handle{Type: PackFile, Name: "foobar"}.String())
+	rtest.Equals(t, "<lock/1>", Handle{Type: LockFile, Name: "1"}.String())
 }
 
 func TestHandleValid(t *testing.T) {
+	var handleTests = []struct {
+		h     Handle
+		valid bool
+	}{
+		{Handle{Name: "foo"}, false},
+		{Handle{Type: 0}, false},
+		{Handle{Type: ConfigFile, Name: ""}, true},
+		{Handle{Type: PackFile, Name: ""}, false},
+		{Handle{Type: LockFile, Name: "010203040506"}, true},
+	}
+
 	for i, test := range handleTests {
 		err := test.h.Valid()
 		if err != nil && test.valid {