Protocol Buffer runtime library and 'protoc' plugin

lib/protobuf/plugin/IndentingWriter.dart

+// 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.
+
+class IndentingWriter implements Writer {
+  IndentingWriter(String this._indentSequence, Writer this._writer)
+    : _currentIndent = "";
+
+  /*
+   * nice shorthand for adding content
+   */
+  void addBlock(String start, String end, void body()) {
+    println(start);
+    indent();
+    body();
+    outdent();
+    println(end);
+  }
+  /*
+   * Shift the left-most character of new lines to the right by one
+   * indentation stop (as set in the constructor).
+   */
+  void indent() {
+    _currentIndent = _currentIndent.concat(_indentSequence);
+  }
+
+  /*
+   * Shift the left-most character of new lines to the left by one
+   * indentation stop (as set in the constructor).
+   */
+  void outdent() {
+    _currentIndent = _currentIndent.substring(0,
+        Math.max(0,_currentIndent.length - _indentSequence.length));
+  }
+
+  void print(String stringToPrint) {
+    if (_currentLine === null) {
+      _currentLine = new StringBuffer();
+    }
+    _currentLine.add(stringToPrint);
+  }
+
+  /*
+   * Add the specified line to the output buffer with the current
+   * level of indent. If the input string is multiple lines,
+   * split them and apply the indent to each line.
+   *
+   * Lines are effectively joined with new-lines (e.g. not appended
+   * to every interim line).
+   */
+  void println([String out = null]) {
+    // TODO - not clear how this plays cross-platform.
+    // more sophisticated patterns don't seem to match.
+    String string;
+    if (_currentLine !== null) {
+      string = _currentLine.add(out === null ? "" : out).toString();
+      _currentLine = null;
+    } else {
+      string = out === null ? "" : out;
+    }
+
+    List<String> lines = string.split("\n");
+    for (String line in lines) {
+      if (line.length > 0) _writer.print(_currentIndent);
+      _writer.println(line);
+    }
+  }
+
+  /*
+   * Add a blank line to the output buffer.
+   */
+  void blankLine() {
+    println("");
+  }
+
+  /*
+   * Push out the current line (see print()) if non-empty.
+   */
+  void flushLine() {
+    if (_currentLine !== null && _currentLine.length > 0) println("");
+  }
+
+  StringBuffer _currentLine;
+  Writer _writer;
+  String _currentIndent;
+  String _indentSequence;
+}