refactor: use slices package for sorting (#10136)

Few more complicated usages of the sort packages are left.

### Purpose

Make progress towards replacing the sort package with slices package.

lib/model/blockpullreorderer.go

@@ -7,7 +7,7 @@
 package model
 
 import (
-	"sort"
+	"slices"
 
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/protocol"
@@ -52,8 +52,8 @@ type standardBlockPullReorderer struct {
 
 func newStandardBlockPullReorderer(id protocol.DeviceID, otherDevices []protocol.DeviceID) *standardBlockPullReorderer {
 	allDevices := append(otherDevices, id)
-	sort.Slice(allDevices, func(i, j int) bool {
-		return allDevices[i].Compare(allDevices[j]) == -1
+	slices.SortFunc(allDevices, func(a, b protocol.DeviceID) int {
+		return a.Compare(b)
 	})
 	// Find our index
 	myIndex := -1

lib/model/blockpullreorderer_test.go

@@ -8,7 +8,7 @@ package model
 
 import (
 	"reflect"
-	"sort"
+	"slices"
 	"testing"
 
 	"github.com/syncthing/syncthing/lib/protocol"
@@ -65,8 +65,8 @@ func Test_inOrderBlockPullReorderer_Reorder(t *testing.T) {
 func Test_standardBlockPullReorderer_Reorder(t *testing.T) {
 	// Order the devices, so we know their ordering ahead of time.
 	devices := []protocol.DeviceID{myID, device1, device2}
-	sort.Slice(devices, func(i, j int) bool {
-		return devices[i].Compare(devices[j]) == -1
+	slices.SortFunc(devices, func(a, b protocol.DeviceID) int {
+		return a.Compare(b)
 	})
 
 	blocks := func(i ...int) []protocol.BlockInfo {

lib/model/folder.go

@@ -13,7 +13,7 @@ import (
 	"math/rand"
 	"path/filepath"
 	"slices"
-	"sort"
+	"strings"
 	"time"
 
 	"github.com/syncthing/syncthing/lib/config"
@@ -1201,7 +1201,9 @@ func (f *folder) Errors() []FileError {
 	errors := make([]FileError, scanLen+len(f.pullErrors))
 	copy(errors[:scanLen], f.scanErrors)
 	copy(errors[scanLen:], f.pullErrors)
-	sort.Sort(fileErrorList(errors))
+	slices.SortFunc(errors, func(a, b FileError) int {
+		return strings.Compare(a.Path, b.Path)
+	})
 	return errors
 }
 

lib/model/folder_recvenc.go

@@ -8,7 +8,8 @@ package model
 
 import (
 	"fmt"
-	"sort"
+	"slices"
+	"strings"
 
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/db"
@@ -112,7 +113,9 @@ func (f *receiveEncryptedFolder) revertHandleDirs(dirs []string, snap *db.Snapsh
 	go f.pullScannerRoutine(scanChan)
 	defer close(scanChan)
 
-	sort.Sort(sort.Reverse(sort.StringSlice(dirs)))
+	slices.SortFunc(dirs, func(a, b string) int {
+		return strings.Compare(b, a)
+	})
 	for _, dir := range dirs {
 		if err := f.deleteDirOnDisk(dir, snap, scanChan); err != nil {
 			f.newScanError(dir, fmt.Errorf("deleting unexpected dir: %w", err))

lib/model/folder_recvonly.go

@@ -7,7 +7,8 @@
 package model
 
 import (
-	"sort"
+	"slices"
+	"strings"
 	"time"
 
 	"github.com/syncthing/syncthing/lib/config"
@@ -207,7 +208,9 @@ func (q *deleteQueue) handle(fi protocol.FileInfo, snap *db.Snapshot) (bool, err
 
 func (q *deleteQueue) flush(snap *db.Snapshot) ([]string, error) {
 	// Process directories from the leaves inward.
-	sort.Sort(sort.Reverse(sort.StringSlice(q.dirs)))
+	slices.SortFunc(q.dirs, func(a, b string) int {
+		return strings.Compare(b, a)
+	})
 
 	var firstError error
 	var deleted []string

lib/model/folder_sendrecv.go

@@ -14,7 +14,7 @@ import (
 	"fmt"
 	"io"
 	"path/filepath"
-	"sort"
+	"slices"
 	"strconv"
 	"strings"
 	"time"
@@ -1867,7 +1867,9 @@ func (f *sendReceiveFolder) moveForConflict(name, lastModBy string, scanChan cha
 	if f.MaxConflicts > -1 {
 		matches := existingConflicts(name, f.mtimefs)
 		if len(matches) > f.MaxConflicts {
-			sort.Sort(sort.Reverse(sort.StringSlice(matches)))
+			slices.SortFunc(matches, func(a, b string) int {
+				return strings.Compare(b, a)
+			})
 			for _, match := range matches[f.MaxConflicts:] {
 				if gerr := f.mtimefs.Remove(match); gerr != nil {
 					l.Debugln(f, "removing extra conflict", gerr)
@@ -2206,20 +2208,6 @@ type FileError struct {
 	Err  string `json:"error"`
 }
 
-type fileErrorList []FileError
-
-func (l fileErrorList) Len() int {
-	return len(l)
-}
-
-func (l fileErrorList) Less(a, b int) bool {
-	return l[a].Path < l[b].Path
-}
-
-func (l fileErrorList) Swap(a, b int) {
-	l[a], l[b] = l[b], l[a]
-}
-
 func conflictName(name, lastModBy string) string {
 	ext := filepath.Ext(name)
 	return name[:len(name)-len(ext)] + time.Now().Format(".sync-conflict-20060102-150405-") + lastModBy + ext

lib/model/queue.go

@@ -7,7 +7,8 @@
 package model
 
 import (
-	"sort"
+	"cmp"
+	"slices"
 	"time"
 
 	"github.com/syncthing/syncthing/lib/rand"
@@ -157,40 +158,34 @@ func (q *jobQueue) SortSmallestFirst() {
 	q.mut.Lock()
 	defer q.mut.Unlock()
 
-	sort.Sort(smallestFirst(q.queued))
+	slices.SortFunc(q.queued, func(a, b jobQueueEntry) int {
+		return cmp.Compare(a.size, b.size)
+	})
 }
 
 func (q *jobQueue) SortLargestFirst() {
 	q.mut.Lock()
 	defer q.mut.Unlock()
 
-	sort.Sort(sort.Reverse(smallestFirst(q.queued)))
+	slices.SortFunc(q.queued, func(a, b jobQueueEntry) int {
+		return cmp.Compare(b.size, a.size)
+	})
 }
 
 func (q *jobQueue) SortOldestFirst() {
 	q.mut.Lock()
 	defer q.mut.Unlock()
 
-	sort.Sort(oldestFirst(q.queued))
+	slices.SortFunc(q.queued, func(a, b jobQueueEntry) int {
+		return cmp.Compare(a.modified, b.modified)
+	})
 }
 
 func (q *jobQueue) SortNewestFirst() {
 	q.mut.Lock()
 	defer q.mut.Unlock()
 
-	sort.Sort(sort.Reverse(oldestFirst(q.queued)))
+	slices.SortFunc(q.queued, func(a, b jobQueueEntry) int {
+		return cmp.Compare(b.modified, a.modified)
+	})
 }
-
-// The usual sort.Interface boilerplate
-
-type smallestFirst []jobQueueEntry
-
-func (q smallestFirst) Len() int           { return len(q) }
-func (q smallestFirst) Less(a, b int) bool { return q[a].size < q[b].size }
-func (q smallestFirst) Swap(a, b int)      { q[a], q[b] = q[b], q[a] }
-
-type oldestFirst []jobQueueEntry
-
-func (q oldestFirst) Len() int           { return len(q) }
-func (q oldestFirst) Less(a, b int) bool { return q[a].modified < q[b].modified }
-func (q oldestFirst) Swap(a, b int)      { q[a], q[b] = q[b], q[a] }