filer: DeleteFolderChildren for deleting large folders

weed/filer2/leveldb/leveldb_store.go

@@ -5,12 +5,13 @@ import (
 	"context"
 	"fmt"
 
-	"github.com/chrislusf/seaweedfs/weed/filer2"
-	"github.com/chrislusf/seaweedfs/weed/glog"
-	weed_util "github.com/chrislusf/seaweedfs/weed/util"
 	"github.com/syndtr/goleveldb/leveldb"
 	"github.com/syndtr/goleveldb/leveldb/opt"
 	leveldb_util "github.com/syndtr/goleveldb/leveldb/util"
+
+	"github.com/chrislusf/seaweedfs/weed/filer2"
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	weed_util "github.com/chrislusf/seaweedfs/weed/util"
 )
 
 const (
@@ -123,6 +124,34 @@ func (store *LevelDBStore) DeleteEntry(ctx context.Context, fullpath filer2.Full
 	return nil
 }
 
+func (store *LevelDBStore) DeleteFolderChildren(ctx context.Context, fullpath filer2.FullPath) (err error) {
+
+	batch := new(leveldb.Batch)
+
+	directoryPrefix := genDirectoryKeyPrefix(fullpath, "")
+	iter := store.db.NewIterator(&leveldb_util.Range{Start: directoryPrefix}, nil)
+	for iter.Next() {
+		key := iter.Key()
+		if !bytes.HasPrefix(key, directoryPrefix) {
+			break
+		}
+		fileName := getNameFromKey(key)
+		if fileName == "" {
+			continue
+		}
+		batch.Delete([]byte(genKey(string(fullpath), fileName)))
+	}
+	iter.Release()
+
+	err = store.db.Write(batch, nil)
+
+	if err != nil {
+		return fmt.Errorf("delete %s : %v", fullpath, err)
+	}
+
+	return nil
+}
+
 func (store *LevelDBStore) ListDirectoryEntries(ctx context.Context, fullpath filer2.FullPath, startFileName string, inclusive bool,
 	limit int) (entries []*filer2.Entry, err error) {