Split id.go into several files

backend/id.go

@@ -102,33 +102,3 @@ func (id *ID) UnmarshalJSON(b []byte) error {
 func IDFromData(d []byte) ID {
 	return hashData(d)
 }
-
-type IDs []ID
-
-func (ids IDs) Len() int {
-	return len(ids)
-}
-
-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
-		} else {
-			return false
-		}
-	}
-
-	return false
-}
-
-func (ids IDs) Swap(i, j int) {
-	ids[i], ids[j] = ids[j], ids[i]
-}

backend/ids.go

@@ -0,0 +1,50 @@
+package backend
+
+// IDs is an ordered list of IDs that implements sort.Interface.
+type IDs []ID
+
+func (ids IDs) Len() int {
+	return len(ids)
+}
+
+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
+}
+
+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
+}

backend/ids_test.go

@@ -0,0 +1,57 @@
+package backend_test
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/restic/restic/backend"
+)
+
+var uniqTests = []struct {
+	before, after backend.IDs
+}{
+	{
+		backend.IDs{
+			str2id("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
+			str2id("1285b30394f3b74693cc29a758d9624996ae643157776fce8154aabd2f01515f"),
+			str2id("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
+		},
+		backend.IDs{
+			str2id("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
+			str2id("1285b30394f3b74693cc29a758d9624996ae643157776fce8154aabd2f01515f"),
+		},
+	},
+	{
+		backend.IDs{
+			str2id("1285b30394f3b74693cc29a758d9624996ae643157776fce8154aabd2f01515f"),
+			str2id("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
+			str2id("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
+		},
+		backend.IDs{
+			str2id("1285b30394f3b74693cc29a758d9624996ae643157776fce8154aabd2f01515f"),
+			str2id("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
+		},
+	},
+	{
+		backend.IDs{
+			str2id("1285b30394f3b74693cc29a758d9624996ae643157776fce8154aabd2f01515f"),
+			str2id("f658198b405d7e80db5ace1980d125c8da62f636b586c46bf81dfb856a49d0c8"),
+			str2id("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
+			str2id("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"),
+		},
+		backend.IDs{
+			str2id("1285b30394f3b74693cc29a758d9624996ae643157776fce8154aabd2f01515f"),
+			str2id("f658198b405d7e80db5ace1980d125c8da62f636b586c46bf81dfb856a49d0c8"),
+			str2id("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)
+		}
+	}
+}

backend/idset.go

@@ -0,0 +1,30 @@
+package backend
+
+// IDSet is a set of IDs.
+type IDSet map[ID]struct{}
+
+// NewIDSet returns a new IDSet, populated with ids.
+func NewIDSet(ids ...ID) IDSet {
+	m := make(IDSet)
+	for _, id := range ids {
+		m[id] = struct{}{}
+	}
+
+	return m
+}
+
+// Has returns true iff id is contained in the set.
+func (s IDSet) Has(id ID) bool {
+	_, ok := s[id]
+	return ok
+}
+
+// Insert adds id to the set.
+func (s IDSet) Insert(id ID) {
+	s[id] = struct{}{}
+}
+
+// Delete removes id from the set.
+func (s IDSet) Delete(id ID) {
+	delete(s, id)
+}

backend/idset_test.go

@@ -0,0 +1,34 @@
+package backend_test
+
+import (
+	"testing"
+
+	"github.com/restic/restic/backend"
+)
+
+var idsetTests = []struct {
+	id   backend.ID
+	seen bool
+}{
+	{str2id("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"), false},
+	{str2id("1285b30394f3b74693cc29a758d9624996ae643157776fce8154aabd2f01515f"), false},
+	{str2id("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"), true},
+	{str2id("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"), true},
+	{str2id("1285b30394f3b74693cc29a758d9624996ae643157776fce8154aabd2f01515f"), true},
+	{str2id("f658198b405d7e80db5ace1980d125c8da62f636b586c46bf81dfb856a49d0c8"), false},
+	{str2id("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"), true},
+	{str2id("1285b30394f3b74693cc29a758d9624996ae643157776fce8154aabd2f01515f"), true},
+	{str2id("f658198b405d7e80db5ace1980d125c8da62f636b586c46bf81dfb856a49d0c8"), true},
+	{str2id("7bb086db0d06285d831485da8031281e28336a56baa313539eaea1c73a2a1a40"), true},
+}
+
+func TestIDSet(t *testing.T) {
+	set := backend.NewIDSet()
+	for i, test := range idsetTests {
+		seen := set.Has(test.id)
+		if seen != test.seen {
+			t.Errorf("IDSet test %v failed: wanted %v, got %v", i, test.seen, seen)
+		}
+		set.Insert(test.id)
+	}
+}