Change the error handling in dart:io

runtime/bin/directory_impl.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 
 class _Directory implements Directory {
   static final kCreateRequest = 0;
   static final kDeleteRequest = 1;
   static final kExistsRequest = 2;
   static final kCreateTempRequest = 3;
@@ skipping 13 matching lines @@
   static _delete(String path, bool recursive) native "Directory_Delete";
   static SendPort _newServicePort() native "Directory_NewServicePort";
 
   void exists(void callback(bool exists)) {
     _ensureDirectoryService();
     List request = new List(2);
     request[0] = kExistsRequest;
     request[1] = _path;
     _directoryService.call(request).then((response) {
       if (_isErrorResponse(response)) {
-        _reportError(response, "Exists failed");
+        _handleErrorResponse(response, "Exists failed");
       } else {
         callback(response == 1);
       }
     });
   }
 
   bool existsSync() {
     if (_path is !String) {
       throw new IllegalArgumentException();
     }
     var result = _exists(_path);
     if (result is OSError) {
       throw new DirectoryIOException("Exists failed", _path, result);
     }
     return (result == 1);
   }
 
   void create(void callback()) {
     _ensureDirectoryService();
     List request = new List(2);
     request[0] = kCreateRequest;
     request[1] = _path;
     _directoryService.call(request).then((response) {
       if (_isErrorResponse(response)) {
-        _reportError(response, "Creation failed");
+        _handleErrorResponse(response, "Creation failed");
       } else {
         callback();
       }
     });
   }
 
   void createSync() {
     if (_path is !String) {
       throw new IllegalArgumentException();
     }
     var result = _create(_path);
     if (result is OSError) {
       throw new DirectoryIOException("Creation failed", _path, result);
     }
   }
 
   void createTemp(void callback()) {
     _ensureDirectoryService();
     List request = new List(2);
     request[0] = kCreateTempRequest;
     request[1] = _path;
     _directoryService.call(request).then((response) {
       if (_isErrorResponse(response)) {
-        _reportError(response, "Creation of temporary directory failed");
+        _handleErrorResponse(response, "Creation of temporary directory failed");
       } else {
         _path = response;
         callback();
       }
     });
   }
 
   void createTempSync() {
     if (_path is !String) {
       throw new IllegalArgumentException();
     }
     var result = _createTemp(path);
     if (result is OSError) {
       throw new DirectoryIOException("Creation of temporary directory failed",
                                      _path,
                                      result);
     }
     _path = result;
   }
 
   void _deleteHelper(bool recursive, String errorMsg, void callback()) {
     _ensureDirectoryService();
     List request = new List(3);
     request[0] = kDeleteRequest;
     request[1] = _path;
     request[2] = recursive;
     _directoryService.call(request).then((response) {
       if (_isErrorResponse(response)) {
-        _reportError(response, errorMsg);
+        _handleErrorResponse(response, errorMsg);
       } else {
         callback();
       }
     });
   }
 
   void delete(void callback()) {
     _deleteHelper(false, "Deletion failed", callback);
   }
 
@@ skipping 36 matching lines @@
     request[0] = kListRequest;
     request[1] = _path;
     request[2] = recursive;
     ReceivePort responsePort = new ReceivePort();
     // Use a separate directory service port for each listing as
     // listing operations on the same directory can run in parallel.
     _newServicePort().send(request, responsePort.toSendPort());
     responsePort.receive((message, replyTo) {
       if (message is !List || message[kResponseType] is !int) {
         responsePort.close();
-        if (_onError != null) {
-          _onError(new DirectoryIOException("Internal error"));
-        }
+        _reportError(new DirectoryIOException("Internal error"));
         return;
       }
       switch (message[kResponseType]) {
         case kListDirectory:
           if (_onDir != null) _onDir(message[kResponsePath]);
           break;
         case kListFile:
           if (_onFile != null) _onFile(message[kResponsePath]);
           break;
         case kListError:
-          if (_onError != null) {
-            var errorType =
-                message[kResponseError][_FileUtils.kErrorResponseErrorType];
-            if (errorType == _FileUtils.kIllegalArgumentResponse) {
-              _onError(new IllegalArgumentException());
-            } else if (errorType == _FileUtils.kOSErrorResponse) {
-              var err = new OSError(
-                  message[kResponseError][_FileUtils.kOSErrorResponseMessage],
-                  message[kResponseError][_FileUtils.kOSErrorResponseErrorCode]);
-              _onError(new DirectoryIOException("Directory listing failed",
-                                                message[kResponsePath],
-                                                err));
-            } else {
-              _onError(new DirectoryIOException("Internal error"));
-            }
+          var errorType =
+              message[kResponseError][_FileUtils.kErrorResponseErrorType];
+          if (errorType == _FileUtils.kIllegalArgumentResponse) {
+            _reportError(new IllegalArgumentException());
+          } else if (errorType == _FileUtils.kOSErrorResponse) {
+            var err = new OSError(
+                message[kResponseError][_FileUtils.kOSErrorResponseMessage],
+                message[kResponseError][_FileUtils.kOSErrorResponseErrorCode]);
+            _reportError(new DirectoryIOException("Directory listing failed",
+                                              message[kResponsePath],
+                                              err));
+          } else {
+            _reportError(new DirectoryIOException("Internal error"));
           }
           break;
         case kListDone:
           responsePort.close();
           if (_onDone != null) _onDone(message[kResponseComplete]);
           break;
       }
     });
   }
 
   void set onDir(void onDir(String dir)) {
     _onDir = onDir;
   }
 
   void set onFile(void onFile(String file)) {
     _onFile = onFile;
   }
 
   void set onDone(void onDone(bool completed)) {
     _onDone = onDone;
   }
 
-  void set onError(void onError(Exception e)) {
+  void set onError(void onError(e)) {
     _onError = onError;
   }
 
   String get path() { return _path; }
 
   void _ensureDirectoryService() {
     if (_directoryService == null) {
       _directoryService = _newServicePort();
     }
   }
 
+  void _reportError(e) {
+    if (_onError != null) {
+      _onError(e);
+    } else {
+      throw e;
+    }
+  }
+
   bool _isErrorResponse(response) {
     return response is List && response[0] != _FileUtils.kSuccessResponse;
   }
 
-  bool _reportError(response, String message) {
+  void _handleErrorResponse(response, String message) {
     assert(_isErrorResponse(response));
-    if (_onError != null) {
-      switch (response[_FileUtils.kErrorResponseErrorType]) {
-        case _FileUtils.kIllegalArgumentResponse:
-          _onError(new IllegalArgumentException());
-          break;
-        case _FileUtils.kOSErrorResponse:
-          var err = new OSError(response[_FileUtils.kOSErrorResponseMessage],
-                                response[_FileUtils.kOSErrorResponseErrorCode]);
-          _onError(new DirectoryIOException(message, _path, err));
-          break;
-        default:
-          _onError(new Exception("Unknown error"));
-          break;
-      }
+    switch (response[_FileUtils.kErrorResponseErrorType]) {
+      case _FileUtils.kIllegalArgumentResponse:
+        _reportError(new IllegalArgumentException());
+        break;
+      case _FileUtils.kOSErrorResponse:
+        var err = new OSError(response[_FileUtils.kOSErrorResponseMessage],
+                              response[_FileUtils.kOSErrorResponseErrorCode]);
+        _reportError(new DirectoryIOException(message, _path, err));
+        break;
+      default:
+        _reportError(new Exception("Unknown error"));
+        break;
     }
   }
 
   Function _onDir;
   Function _onFile;
   Function _onDone;
   Function _onError;
 
   String _path;
   SendPort _directoryService;
 }