Improve utils of slices (#22379)

- Move the file `compare.go` and `slice.go` to `slice.go`.
- Fix `ExistsInSlice`, it's buggy
  - It uses `sort.Search`, so it assumes that the input slice is sorted.
- It passes `func(i int) bool { return slice[i] == target })` to
`sort.Search`, that's incorrect, check the doc of `sort.Search`.
- Conbine `IsInt64InSlice(int64, []int64)` and `ExistsInSlice(string,
[]string)` to `SliceContains[T]([]T, T)`.
- Conbine `IsSliceInt64Eq([]int64, []int64)` and `IsEqualSlice([]string,
[]string)` to `SliceSortedEqual[T]([]T, T)`.
- Add `SliceEqual[T]([]T, T)` as a distinction from
`SliceSortedEqual[T]([]T, T)`.
- Redesign `RemoveIDFromList([]int64, int64) ([]int64, bool)` to
`SliceRemoveAll[T]([]T, T) []T`.
- Add `SliceContainsFunc[T]([]T, func(T) bool)` and
`SliceRemoveAllFunc[T]([]T, func(T) bool)` for general use.
- Add comments to explain why not `golang.org/x/exp/slices`.
- Add unit tests.

models/asymkey/ssh_key.go

@@ -409,14 +409,14 @@ func SynchronizePublicKeys(usr *user_model.User, s *auth.Source, sshPublicKeys [
 		sshKeySplit := strings.Split(v, " ")
 		if len(sshKeySplit) > 1 {
 			key := strings.Join(sshKeySplit[:2], " ")
-			if !util.ExistsInSlice(key, providedKeys) {
+			if !util.SliceContainsString(providedKeys, key) {
 				providedKeys = append(providedKeys, key)
 			}
 		}
 	}
 
 	// Check if Public Key sync is needed
-	if util.IsEqualSlice(giteaKeys, providedKeys) {
+	if util.SliceSortedEqual(giteaKeys, providedKeys) {
 		log.Trace("synchronizePublicKeys[%s]: Public Keys are already in sync for %s (Source:%v/DB:%v)", s.Name, usr.Name, len(providedKeys), len(giteaKeys))
 		return false
 	}
@@ -425,7 +425,7 @@ func SynchronizePublicKeys(usr *user_model.User, s *auth.Source, sshPublicKeys [
 	// Add new Public SSH Keys that doesn't already exist in DB
 	var newKeys []string
 	for _, key := range providedKeys {
-		if !util.ExistsInSlice(key, giteaKeys) {
+		if !util.SliceContainsString(giteaKeys, key) {
 			newKeys = append(newKeys, key)
 		}
 	}
@@ -436,7 +436,7 @@ func SynchronizePublicKeys(usr *user_model.User, s *auth.Source, sshPublicKeys [
 	// Mark keys from DB that no longer exist in the source for deletion
 	var giteaKeysToDelete []string
 	for _, giteaKey := range giteaKeys {
-		if !util.ExistsInSlice(giteaKey, providedKeys) {
+		if !util.SliceContainsString(providedKeys, giteaKey) {
 			log.Trace("synchronizePublicKeys[%s]: Marking Public SSH Key for deletion for user %s: %v", s.Name, usr.Name, giteaKey)
 			giteaKeysToDelete = append(giteaKeysToDelete, giteaKey)
 		}