restic: Clean up restic.IDs type

IDs.Less can be rewritten as

	string(list[i][:]) < string(list[j][:])

Note that this does not copy the ID's.

The Uniq method was no longer used.

The String method has been reimplemented without first copying into a
separate slice of a custom type.

internal/restic/ids.go

@@ -2,10 +2,10 @@ package restic
 
 import (
 	"encoding/hex"
-	"fmt"
+	"strings"
 )
 
-// IDs is an ordered list of IDs that implements sort.Interface.
+// IDs is a slice of IDs that implements sort.Interface and fmt.Stringer.
 type IDs []ID
 
 func (ids IDs) Len() int {
@@ -13,57 +13,28 @@ func (ids IDs) Len() int {
 }
 
 func (ids IDs) Less(i, j int) bool {
-	if len(ids[i]) < len(ids[j]) {
-		return true
-	}
-
-	for k, b := range ids[i] {
-		if b == ids[j][k] {
-			continue
-		}
-
-		if b < ids[j][k] {
-			return true
-		}
-
-		return false
-	}
-
-	return false
+	return string(ids[i][:]) < string(ids[j][:])
 }
 
 func (ids IDs) Swap(i, j int) {
 	ids[i], ids[j] = ids[j], ids[i]
 }
 
-// Uniq returns list without duplicate IDs. The returned list retains the order
-// of the original list so that the order of the first occurrence of each ID
-// stays the same.
-func (ids IDs) Uniq() (list IDs) {
-	seen := NewIDSet()
-
-	for _, id := range ids {
-		if seen.Has(id) {
-			continue
-		}
-
-		list = append(list, id)
-		seen.Insert(id)
-	}
-
-	return list
-}
-
-type shortID ID
-
-func (id shortID) String() string {
-	return hex.EncodeToString(id[:shortStr])
-}
-
 func (ids IDs) String() string {
-	elements := make([]shortID, 0, len(ids))
-	for _, id := range ids {
-		elements = append(elements, shortID(id))
+	var sb strings.Builder
+	sb.Grow(1 + (1+2*shortStr)*len(ids))
+
+	buf := make([]byte, 2*shortStr)
+
+	sb.WriteByte('[')
+	for i, id := range ids {
+		if i > 0 {
+			sb.WriteByte(' ')
+		}
+		hex.Encode(buf, id[:shortStr])
+		sb.Write(buf)
 	}
-	return fmt.Sprint(elements)
+	sb.WriteByte(']')
+
+	return sb.String()
 }

internal/restic/ids_test.go

@@ -1,55 +1,17 @@
 package restic
 
 import (
-	"reflect"
 	"testing"
+
+	rtest "github.com/restic/restic/internal/test"
 )
 
-var uniqTests = []struct {
-	before, after IDs
-}{
-	{
-		IDs{
-			TestParseID("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
-			TestParseID("1285b30394f3b74693cc29a758d9624996ae643157776fce8154aabd2f01515f"),
-			TestParseID("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
-		},
-		IDs{
-			TestParseID("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
-			TestParseID("1285b30394f3b74693cc29a758d9624996ae643157776fce8154aabd2f01515f"),
-		},
-	},
-	{
-		IDs{
-			TestParseID("1285b30394f3b74693cc29a758d9624996ae643157776fce8154aabd2f01515f"),
-			TestParseID("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
-			TestParseID("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
-		},
-		IDs{
-			TestParseID("1285b30394f3b74693cc29a758d9624996ae643157776fce8154aabd2f01515f"),
-			TestParseID("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
-		},
-	},
-	{
-		IDs{
-			TestParseID("1285b30394f3b74693cc29a758d9624996ae643157776fce8154aabd2f01515f"),
-			TestParseID("f658198b405d7e80db5ace1980d125c8da62f636b586c46bf81dfb856a49d0c8"),
-			TestParseID("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
-			TestParseID("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
-		},
-		IDs{
-			TestParseID("1285b30394f3b74693cc29a758d9624996ae643157776fce8154aabd2f01515f"),
-			TestParseID("f658198b405d7e80db5ace1980d125c8da62f636b586c46bf81dfb856a49d0c8"),
-			TestParseID("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
-		},
-	},
-}
-
-func TestUniqIDs(t *testing.T) {
-	for i, test := range uniqTests {
-		uniq := test.before.Uniq()
-		if !reflect.DeepEqual(uniq, test.after) {
-			t.Errorf("uniqIDs() test %v failed\n  wanted: %v\n  got: %v", i, test.after, uniq)
-		}
+func TestIDsString(t *testing.T) {
+	ids := IDs{
+		TestParseID("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
+		TestParseID("1285b30394f3b74693cc29a758d9624996ae643157776fce8154aabd2f01515f"),
+		TestParseID("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
 	}
+
+	rtest.Equals(t, "[7bb086db 1285b303 7bb086db]", ids.String())
 }

internal/restic/idset.go

@@ -31,7 +31,7 @@ func (s IDSet) Delete(id ID) {
 	delete(s, id)
 }
 
-// List returns a slice of all IDs in the set.
+// List returns a sorted slice of all IDs in the set.
 func (s IDSet) List() IDs {
 	list := make(IDs, 0, len(s))
 	for id := range s {
@@ -103,9 +103,5 @@ func (s IDSet) Sub(other IDSet) (result IDSet) {
 
 func (s IDSet) String() string {
 	str := s.List().String()
-	if len(str) < 2 {
-		return "{}"
-	}
-
 	return "{" + str[1:len(str)-1] + "}"
 }

internal/restic/idset_test.go

@@ -2,6 +2,8 @@ package restic
 
 import (
 	"testing"
+
+	rtest "github.com/restic/restic/internal/test"
 )
 
 var idsetTests = []struct {
@@ -22,6 +24,8 @@ var idsetTests = []struct {
 
 func TestIDSet(t *testing.T) {
 	set := NewIDSet()
+	rtest.Equals(t, "{}", set.String())
+
 	for i, test := range idsetTests {
 		seen := set.Has(test.id)
 		if seen != test.seen {
@@ -29,4 +33,6 @@ func TestIDSet(t *testing.T) {
 		}
 		set.Insert(test.id)
 	}
+
+	rtest.Equals(t, "{1285b303 7bb086db f658198b}", set.String())
 }