Fix several Windows issues.

lib/src/cr_lf_remover.dart

+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS d.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.
+
+library pub.cr_lf_remover;
+
+import 'dart:convert';
+
+import 'package:charcode/ascii.dart';
+
+/// A converter that removes CR characters immediately preceding LF characters.
+///
+/// This is useful when piping output from a Dart process on Windows. Due to
+/// sdk#19334, an extra CR is added before every LF, even if one already
+/// existed, which can cause data to become corrupted. By converting CR LFs to
+/// LFs, this class ensures that when the output is emitted through the parent
+/// process's stdout it will be identical to the output emitted by the child.
+///
+/// Note that this will only work properly for Dart subprocesses, because
+/// sdk#19334 guarantees that they will *never* emit an LF without a preceding
+/// CR.
+class CRLFRemover extends Converter<List<int>, List<int>> {
+  const CRLFRemover();
+
+  List<int> convert(List<int> data) {
+    var result;
+    var sink = startChunkedConversion(
+        new ByteConversionSink.withCallback((result_) => result = result_));
+    sink.add(data);
+    sink.close();
+    return result;
+  }
+
+  ChunkedConversionSink startChunkedConversion(Sink<List<int>> sink) {
+    if (sink is! ByteConversionSink) sink = new ByteConversionSink.from(sink);

[Bob Nystrom, 2015/07/08 22:12:15]

Document this.

[nweiz, 2015/07/09 00:30:14]

Done.

+    return new _CRLFSink(sink);
+  }
+}
+
+/// The custom sink used to do chunked removal of CRs.
+class _CRLFSink extends ByteConversionSink {
+  /// Whether the last chunk ended in CR.
+  ///
+  /// If it did, that CR wasn't printed in case it needs to be removed.
+  var _wasCR = false;
+
+  /// The underlying sink.
+  final ByteConversionSink _sink;
+
+  _CRLFSink(this._sink);
+
+  void add(Iterable<int> chunk) {
+    if (chunk is! List) chunk = chunk.toList();
+    addSlice(chunk, 0, chunk.length, false);
+  }
+
+  void addSlice(List<int> chunk, int start, int end, bool isLast) {
+    var wasCR = _wasCR;
+    var nextSliceStart = start;
+    for (var i = start; i < end; i++) {
+      if (wasCR && chunk[i] == $lf) {
+        if (i != start) {
+          _sink.addSlice(chunk, nextSliceStart, i - 1, false);
+          nextSliceStart = i;
+        }
+      } else if (_wasCR && i == start) {
+        // If the last chunk ended in a CR and this chunk *doesn't* start with
+        // an LF, we need to write the CR from the last chunk.
+        _sink.add([$cr]);
+      }
+
+      wasCR = chunk[i] == $cr;
+    }
+
+    _wasCR = wasCR;
+    var finalSliceEnd = wasCR ? end - 1 : end;
+    _sink.addSlice(chunk, nextSliceStart, finalSliceEnd, isLast);
+  }
+
+  void close() {
+    if (_wasCR) _sink.add([$cr]);
+    _sink.close();
+  }
+}