Add pipe to input stream

runtime/bin/stream_util.dart

Index: runtime/bin/stream_util.dart
diff --git a/runtime/bin/stream_util.dart b/runtime/bin/stream_util.dart
new file mode 100644
index 0000000000000000000000000000000000000000..1c9cca3123e394754a7c2fbef3039f0087918946
--- /dev/null
+++ b/runtime/bin/stream_util.dart
@@ -0,0 +1,38 @@
+// Copyright (c) 2011, 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.
+
+void _pipe(InputStream input, OutputStream output, [bool close]) {
+  Function pipeDataHandler;
+  Function pipeCloseHandler;
+  Function pipeNoPendingWriteHandler;
+
+  Function _inputCloseHandler;
+
+  pipeDataHandler = () {
+    List<int> data;
+    while ((data = input.read()) !== null) {
+      if (!output.write(data)) {
+        input.dataHandler = null;
+        output.noPendingWriteHandler = pipeNoPendingWriteHandler;
+        break;
+      }
+    }
+  };
+
+  pipeCloseHandler = () {
+    if (close) output.close();
+    if (_inputCloseHandler !== null) _inputCloseHandler();
+  };
+
+  pipeNoPendingWriteHandler = () {
+    input.dataHandler = pipeDataHandler;
+    output.noPendingWriteHandler = null;
+  };
+
+  _inputCloseHandler = input._clientCloseHandler;
+  input.dataHandler = pipeDataHandler;
+  input.closeHandler = pipeCloseHandler;
+  output.noPendingWriteHandler = null;
+}
+