Add more API fuzzing and fix the issues encountered.

runtime/bin/file_impl.dart

Index: runtime/bin/file_impl.dart
diff --git a/runtime/bin/file_impl.dart b/runtime/bin/file_impl.dart
index 10a5cfc9b393f835ab03825f7a5dcabc3e2c79ce..a90b0dcc5e6e01589f7267c2d6628f65c40ecfb0 100644
--- a/runtime/bin/file_impl.dart
+++ b/runtime/bin/file_impl.dart
@@ -650,8 +650,8 @@ class _File extends _FileBase implements File {
 
   Future<String> readAsText([Encoding encoding = Encoding.UTF_8]) {
     _ensureFileService();
-    var decoder = _StringDecoders.decoder(encoding);
     return readAsBytes().transform((bytes) {
+      var decoder = _StringDecoders.decoder(encoding);
       decoder.write(bytes);
       return decoder.decoded;
     });
@@ -683,8 +683,8 @@ class _File extends _FileBase implements File {
   Future<List<String>> readAsLines([Encoding encoding = Encoding.UTF_8]) {
     _ensureFileService();
     Completer<List<String>> completer = new Completer<List<String>>();
-    var decoder = _StringDecoders.decoder(encoding);
     return readAsBytes().transform((bytes) {
+      var decoder = _StringDecoders.decoder(encoding);
       decoder.write(bytes);
       return _getDecodedLines(decoder);
     });
@@ -716,7 +716,7 @@ class _RandomAccessFile extends _FileBase implements RandomAccessFile {
 
   Future<RandomAccessFile> close() {
     Completer<RandomAccessFile> completer = new Completer<RandomAccessFile>();
-    if (_id == 0) {
+    if (_isClosed) {
       // Complete asynchronously so the user has a chance to setup
       // handlers without getting exceptions when registering the
       // then handler.
@@ -756,6 +756,13 @@ class _RandomAccessFile extends _FileBase implements RandomAccessFile {
   Future<int> readByte() {
     _ensureFileService();
     Completer<int> completer = new Completer<int>();
+    if (_isClosed) {

[Søren Gjesse, 2012/05/16 11:54:11]

Add a function for closed exception as 4 lines of code are repeated below.

[Mads Ager (google), 2012/05/16 12:45:19]

Done. Each of these replaced by:

if (_isClosed) return _completeWithClosedException(completer);

+      new Timer(0, (t) {
+        completer.completeException(
+            new FileIOException("File closed '$_name'"));
+      });
+      return completer.future;
+    }
     List request = new List(2);
     request[0] = _FileUtils.kReadByteRequest;
     request[1] = _id;
@@ -793,6 +800,13 @@ class _RandomAccessFile extends _FileBase implements RandomAccessFile {
       });
       return completer.future;
     };
+    if (_isClosed) {
+      new Timer(0, (t) {
+        completer.completeException(
+            new FileIOException("File closed '$_name'"));
+      });
+      return completer.future;
+    }
     List request = new List(3);
     request[0] = _FileUtils.kReadListRequest;
     request[1] = _id;
@@ -845,6 +859,13 @@ class _RandomAccessFile extends _FileBase implements RandomAccessFile {
       });
       return completer.future;
     }
+    if (_isClosed) {
+      new Timer(0, (t) {
+        completer.completeException(
+            new FileIOException("File closed '$_name'"));
+      });
+      return completer.future;
+    }
     List request = new List(3);
     request[0] = _FileUtils.kWriteByteRequest;
     request[1] = _id;
@@ -888,6 +909,13 @@ class _RandomAccessFile extends _FileBase implements RandomAccessFile {
       });
       return completer.future;
     }
+    if (_isClosed) {
+      new Timer(0, (t) {
+        completer.completeException(
+            new FileIOException("File closed '$_name'"));
+      });
+      return completer.future;
+    }
 
     List result =
         _FileUtils.ensureFastAndSerializableBuffer(buffer, offset, bytes);
@@ -935,6 +963,13 @@ class _RandomAccessFile extends _FileBase implements RandomAccessFile {
                                        [Encoding encoding = Encoding.UTF_8]) {
     _ensureFileService();
     Completer<RandomAccessFile> completer = new Completer<RandomAccessFile>();
+    if (_isClosed) {
+      new Timer(0, (t) {
+        completer.completeException(
+            new FileIOException("File closed '$_name'"));
+      });
+      return completer.future;
+    }
     List request = new List(3);
     request[0] = _FileUtils.kWriteStringRequest;
     request[1] = _id;
@@ -963,6 +998,13 @@ class _RandomAccessFile extends _FileBase implements RandomAccessFile {
   Future<int> position() {
     _ensureFileService();
     Completer<int> completer = new Completer<int>();
+    if (_isClosed) {
+      new Timer(0, (t) {
+        completer.completeException(
+            new FileIOException("File closed '$_name'"));
+      });
+      return completer.future;
+    }
     List request = new List(2);
     request[0] = _FileUtils.kPositionRequest;
     request[1] = _id;
@@ -990,6 +1032,13 @@ class _RandomAccessFile extends _FileBase implements RandomAccessFile {
   Future<RandomAccessFile> setPosition(int position) {
     _ensureFileService();
     Completer<RandomAccessFile> completer = new Completer<RandomAccessFile>();
+    if (_isClosed) {
+      new Timer(0, (t) {
+        completer.completeException(
+            new FileIOException("File closed '$_name'"));
+      });
+      return completer.future;
+    }
     List request = new List(3);
     request[0] = _FileUtils.kSetPositionRequest;
     request[1] = _id;
@@ -1017,6 +1066,13 @@ class _RandomAccessFile extends _FileBase implements RandomAccessFile {
   Future<RandomAccessFile> truncate(int length) {
     _ensureFileService();
     Completer<RandomAccessFile> completer = new Completer<RandomAccessFile>();
+    if (_isClosed) {
+      new Timer(0, (t) {
+        completer.completeException(
+            new FileIOException("File closed '$_name'"));
+      });
+      return completer.future;
+    }
     List request = new List(3);
     request[0] = _FileUtils.kTruncateRequest;
     request[1] = _id;
@@ -1044,6 +1100,13 @@ class _RandomAccessFile extends _FileBase implements RandomAccessFile {
   Future<int> length() {
     _ensureFileService();
     Completer<int> completer = new Completer<int>();
+    if (_isClosed) {
+      new Timer(0, (t) {
+        completer.completeException(
+            new FileIOException("File closed '$_name'"));
+      });
+      return completer.future;
+    }
     List request = new List(2);
     request[0] = _FileUtils.kLengthRequest;
     request[1] = _id;
@@ -1071,6 +1134,13 @@ class _RandomAccessFile extends _FileBase implements RandomAccessFile {
   Future<RandomAccessFile> flush() {
     _ensureFileService();
     Completer<RandomAccessFile> completer = new Completer<RandomAccessFile>();
+    if (_isClosed) {
+      new Timer(0, (t) {
+        completer.completeException(
+            new FileIOException("File closed '$_name'"));
+      });
+      return completer.future;
+    }
     List request = new List(2);
     request[0] = _FileUtils.kFlushRequest;
     request[1] = _id;
@@ -1102,8 +1172,10 @@ class _RandomAccessFile extends _FileBase implements RandomAccessFile {
     }
   }
 
+  bool get _isClosed() => _id == 0;
+
   void _checkNotClosed() {
-    if (_id == 0) {
+    if (_isClosed) {
       throw new FileIOException("File closed '$_name'");
     }
   }