fix leak

iOSClient/Networking/NCOperationQueue.swift

@@ -349,12 +349,18 @@ class NCOperationDownloadThumbnail: ConcurrentOperation {
     var urlBase: String
     var view: Any
     var indexPath: IndexPath
+    var fileNamePath: String = ""
+    var fileNamePreviewLocalPath: String = ""
+    var fileNameIconLocalPath: String = ""
     
     init(metadata: tableMetadata, urlBase: String, view: Any, indexPath: IndexPath) {
         self.metadata = tableMetadata.init(value: metadata)
         self.urlBase = urlBase
         self.view = view
         self.indexPath = indexPath
+        self.fileNamePath = CCUtility.returnFileNamePath(fromFileName: metadata.fileName, serverUrl: metadata.serverUrl, urlBase: urlBase, account: metadata.account)!
+        self.fileNamePreviewLocalPath = CCUtility.getDirectoryProviderStoragePreviewOcId(metadata.ocId, etag: metadata.etag)!
+        self.fileNameIconLocalPath = CCUtility.getDirectoryProviderStorageIconOcId(metadata.ocId, etag: metadata.etag)!
     }
     
     override func start() {
@@ -362,10 +368,6 @@ class NCOperationDownloadThumbnail: ConcurrentOperation {
         if isCancelled {
             self.finish()
         } else {
-            let fileNamePath = CCUtility.returnFileNamePath(fromFileName: metadata.fileName, serverUrl: metadata.serverUrl, urlBase: urlBase, account: metadata.account)!
-            let fileNamePreviewLocalPath = CCUtility.getDirectoryProviderStoragePreviewOcId(metadata.ocId, etag: metadata.etag)!
-            let fileNameIconLocalPath = CCUtility.getDirectoryProviderStorageIconOcId(metadata.ocId, etag: metadata.etag)!
-
             NCCommunication.shared.downloadPreview(fileNamePathOrFileId: fileNamePath, fileNamePreviewLocalPath: fileNamePreviewLocalPath , widthPreview: NCGlobal.shared.sizePreview, heightPreview: NCGlobal.shared.sizePreview, fileNameIconLocalPath: fileNameIconLocalPath, sizeIcon: NCGlobal.shared.sizeIcon) { (account, imagePreview, imageIcon,  errorCode, errorDescription) in
                 
                 var cell: NCImageCellProtocol?