dart:io | Implement asynchronous versions of FileSystemEntity methods.

sdk/lib/io/common.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.
 
 part of dart.io;
 
 // Constants used when working with native ports.
 const int _SUCCESS_RESPONSE = 0;
 const int _ILLEGAL_ARGUMENT_RESPONSE = 1;
 const int _OSERROR_RESPONSE = 2;
 const int _FILE_CLOSED_RESPONSE = 3;
 
 const int _ERROR_RESPONSE_ERROR_TYPE = 0;
 const int _OSERROR_RESPONSE_ERROR_CODE = 1;
 const int _OSERROR_RESPONSE_MESSAGE = 2;
 
+// Functions used to receive exceptions from native ports.
+bool _isErrorResponse(response) {
+  return response is List && response[0] != _SUCCESS_RESPONSE;
+}
+
+/**
+ * Returns an Exception or an Error
+ */
+_exceptionFromResponse(response, String message) {
+  assert(_isErrorResponse(response));
+  switch (response[_ERROR_RESPONSE_ERROR_TYPE]) {
+    case _ILLEGAL_ARGUMENT_RESPONSE:
+      return new ArgumentError();
+    case _OSERROR_RESPONSE:
+      var err = new OSError(response[_OSERROR_RESPONSE_MESSAGE],
+                            response[_OSERROR_RESPONSE_ERROR_CODE]);
+      return new FileIOException(message, err);
+    case _FILE_CLOSED_RESPONSE:
+      return new FileIOException("File closed");
+    default:
+      return new Exception("Unknown error");
+  }
+}
+
 /**
   * An [OSError] object holds information about an error from the
   * operating system.
   */
 class OSError implements Error {
   /** Constant used to indicate that no OS error code is available. */
   static const int noErrorCode = -1;
 
   /** Creates an OSError object from a message and an errorCode. */
   const OSError([String this.message = "", int this.errorCode = noErrorCode]);
@@ skipping 77 matching lines @@
 class _BufferUtils {
   // Check if a List is a builtin VM List type. Returns true
   // if the List is a builtin VM List type and false if it is
   // a user defined List type.
   external static bool _isBuiltinList(List buffer);
 }
 
 class _IOCrypto {
   external static Uint8List getRandomBytes(int count);
 }