Ensure to close file-stream on all errors.

sdk/lib/io/file_impl.dart

 // Copyright (c) 2013, 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;
 
 // Read the file in blocks of size 64k.
 const int _BLOCK_SIZE = 64 * 1024;
 
 
@@ skipping 58 matching lines @@
   }
 
   void _readBlock() {
     // Don't start a new read if one is already in progress.
     if (_readInProgress) return;
     _readInProgress = true;
     int readBytes = _BLOCK_SIZE;
     if (_end != null) {
       readBytes = min(readBytes, _end - _position);
       if (readBytes < 0) {
-        throw new RangeError("Bad end position: $_end");
+        if (!_unsubscribed) {
+          _controller.addError(new RangeError("Bad end position: $_end"));
+          _closeFile().then((_) { _controller.close(); });

[kustermann, 2013/05/21 11:23:57]

I don't know if the Future returned by '_closeFile()' can complete with an
error?

[Anders Johnsen, 2013/05/21 11:37:27]

I'm quite sure it can't. Can't come to think of any scenario at least.

+          _unsubscribed = true;
+        }
+        return;
       }
     }
     _openedFile.read(readBytes)
       .then((block) {
         _readInProgress = false;
         if (block.length == 0) {
           if (!_unsubscribed) {
             _closeFile().then((_) { _controller.close(); });
             _unsubscribed = true;
           }
@@ skipping 10 matching lines @@
       .catchError((e) {
         if (!_unsubscribed) {
           _controller.addError(e);
           _closeFile().then((_) { _controller.close(); });
           _unsubscribed = true;
         }
       });
   }
 
   void _start() {
+    if (_position == null) {
+      _position = 0;
+    } else if (_position < 0) {
+      _controller.addError(new RangeError("Bad start position: $_position"));
+      _controller.close();
+      return;
+    }
     Future<RandomAccessFile> openFuture;
     if (_path != null) {
       openFuture = new File(_path).open(mode: FileMode.READ);
     } else {
       openFuture = new Future.value(_File._openStdioSync(0));
     }
     openFuture
       .then((RandomAccessFile opened) {
         _openedFile = opened;
-        if (_position == null) {
-          _position = 0;
-        }
         if (_position > 0) {
           return opened.setPosition(_position);
-        } else if (_position < 0) {
-          throw new RangeError("Bad start position: $_position");
         }
       })
       .then((_) => _readBlock())
       .catchError((e) {
         _controller.addError(e);
         _controller.close();
       });
   }
 
   void _resume() {
@@ skipping 891 matching lines @@
           new FileIOException("File closed '$_path'"));
     });
     return completer.future;
   }
 
   final String _path;
   int _id;
 
   SendPort _fileService;
 }