gui: Add addresses for disconnected devices (fixes #3340)

Also fixes an issue where the discovery cache call would only return the
newest cache entry for a given device instead of the merged addresses
from all cache entries (which is more useful).

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3344

lib/versioner/simple.go

@@ -12,6 +12,7 @@ import (
 	"strconv"
 
 	"github.com/syncthing/syncthing/lib/osutil"
+	"github.com/syncthing/syncthing/lib/util"
 )
 
 func init() {
@@ -102,7 +103,7 @@ func (v Simple) Archive(filePath string) error {
 
 	// Use all the found filenames. "~" sorts after "." so all old pattern
 	// files will be deleted before any new, which is as it should be.
-	versions := uniqueSortedStrings(append(oldVersions, newVersions...))
+	versions := util.UniqueStrings(append(oldVersions, newVersions...))
 
 	if len(versions) > v.keep {
 		for _, toRemove := range versions[:len(versions)-v.keep] {

lib/versioner/staggered.go

@@ -14,6 +14,7 @@ import (
 
 	"github.com/syncthing/syncthing/lib/osutil"
 	"github.com/syncthing/syncthing/lib/sync"
+	"github.com/syncthing/syncthing/lib/util"
 )
 
 func init() {
@@ -280,7 +281,7 @@ func (v Staggered) Archive(filePath string) error {
 
 	// Use all the found filenames.
 	versions := append(oldVersions, newVersions...)
-	v.expire(uniqueSortedStrings(versions))
+	v.expire(util.UniqueStrings(versions))
 
 	return nil
 }

lib/versioner/util.go

@@ -9,7 +9,6 @@ package versioner
 import (
 	"path/filepath"
 	"regexp"
-	"sort"
 )
 
 // Inserts ~tag just before the extension of the filename.
@@ -32,17 +31,3 @@ func filenameTag(path string) string {
 	}
 	return match[1]
 }
-
-func uniqueSortedStrings(strings []string) []string {
-	seen := make(map[string]struct{}, len(strings))
-	unique := make([]string, 0, len(strings))
-	for _, str := range strings {
-		_, ok := seen[str]
-		if !ok {
-			seen[str] = struct{}{}
-			unique = append(unique, str)
-		}
-	}
-	sort.Strings(unique)
-	return unique
-}