move polymer.dart into dart svn

pkg/polymer/lib/src/utils.dart

+// Copyright (c) 2012, 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.
+
+library polymer.src.utils;
+
+import 'dart:async';
+import 'package:path/path.dart' show Builder;
+export 'utils_observe.dart' show toCamelCase, toHyphenedName;
+
+/**
+ * An instance of the pathos library builder. We could just use the default
+ * builder in pathos, but we add this indirection to make it possible to run
+ * unittest for windows paths.
+ */
+Builder path = new Builder();
+
+/** Convert a OS specific path into a url. */
+String pathToUrl(String relPath) =>
+  (path.separator == '/') ? relPath : path.split(relPath).join('/');
+
+/**
+ * Invokes [callback], logs how long it took to execute in ms, and returns
+ * whatever [callback] returns. The log message will be printed if [printTime]
+ * is true.
+ */
+time(String logMessage, callback(),
+     {bool printTime: false, bool useColors: false}) {
+  final watch = new Stopwatch();
+  watch.start();
+  var result = callback();
+  watch.stop();
+  final duration = watch.elapsedMilliseconds;
+  if (printTime) {
+    _printMessage(logMessage, duration, useColors);
+  }
+  return result;
+}
+
+/**
+ * Invokes [callback], logs how long it takes from the moment [callback] is
+ * executed until the future it returns is completed. Returns the future
+ * returned by [callback]. The log message will be printed if [printTime]
+ * is true.
+ */
+Future asyncTime(String logMessage, Future callback(),
+                 {bool printTime: false, bool useColors: false}) {
+  final watch = new Stopwatch();
+  watch.start();
+  return callback()..then((_) {
+    watch.stop();
+    final duration = watch.elapsedMilliseconds;
+    if (printTime) {
+      _printMessage(logMessage, duration, useColors);
+    }
+  });
+}
+
+void _printMessage(String logMessage, int duration, bool useColors) {
+  var buf = new StringBuffer();
+  buf.write(logMessage);
+  for (int i = logMessage.length; i < 60; i++) buf.write(' ');
+  buf.write(' -- ');
+  if (useColors) {
+    buf.write(GREEN_COLOR);
+  }
+  if (duration < 10) buf.write(' ');
+  if (duration < 100) buf.write(' ');
+  buf..write(duration)..write(' ms');
+  if (useColors) {
+    buf.write(NO_COLOR);
+  }
+  print(buf.toString());
+}
+
+// Color constants used for generating messages.
+final String GREEN_COLOR = '\u001b[32m';
+final String RED_COLOR = '\u001b[31m';
+final String MAGENTA_COLOR = '\u001b[35m';
+final String NO_COLOR = '\u001b[0m';
+
+/** A future that waits until all added [Future]s complete. */
+// TODO(sigmund): this should be part of the futures/core libraries.
+class FutureGroup {
+  static const _FINISHED = -1;
+
+  int _pending = 0;
+  Future _failedTask;
+  final Completer<List> _completer = new Completer<List>();
+  final List results = [];
+
+  /** Gets the task that failed, if any. */
+  Future get failedTask => _failedTask;
+
+  /**
+   * Wait for [task] to complete.
+   *
+   * If this group has already been marked as completed, you'll get a
+   * [StateError].
+   *
+   * If this group has a [failedTask], new tasks will be ignored, because the
+   * error has already been signaled.
+   */
+  void add(Future task) {
+    if (_failedTask != null) return;
+    if (_pending == _FINISHED) throw new StateError("Future already completed");
+
+    _pending++;
+    var i = results.length;
+    results.add(null);
+    task.then((res) {
+      results[i] = res;
+      if (_failedTask != null) return;
+      _pending--;
+      if (_pending == 0) {
+        _pending = _FINISHED;
+        _completer.complete(results);
+      }
+    }, onError: (e) {
+      if (_failedTask != null) return;
+      _failedTask = task;
+      _completer.completeError(e, getAttachedStackTrace(e));
+    });
+  }
+
+  Future<List> get future => _completer.future;
+}
+
+
+/**
+ * Escapes [text] for use in a Dart string.
+ * [single] specifies single quote `'` vs double quote `"`.
+ * [triple] indicates that a triple-quoted string, such as `'''` or `"""`.
+ */
+String escapeDartString(String text, {bool single: true, bool triple: false}) {
+  // Note: don't allocate anything until we know we need it.
+  StringBuffer result = null;
+
+  for (int i = 0; i < text.length; i++) {
+    int code = text.codeUnitAt(i);
+    var replace = null;
+    switch (code) {
+      case 92/*'\\'*/: replace = r'\\'; break;
+      case 36/*r'$'*/: replace = r'\$'; break;
+      case 34/*'"'*/:  if (!single) replace = r'\"'; break;
+      case 39/*"'"*/:  if (single) replace = r"\'"; break;
+      case 10/*'\n'*/: if (!triple) replace = r'\n'; break;
+      case 13/*'\r'*/: if (!triple) replace = r'\r'; break;
+
+      // Note: we don't escape unicode characters, under the assumption that
+      // writing the file in UTF-8 will take care of this.
+
+      // TODO(jmesserly): do we want to replace any other non-printable
+      // characters (such as \f) for readability?
+    }
+
+    if (replace != null && result == null) {
+      result = new StringBuffer(text.substring(0, i));
+    }
+
+    if (result != null) result.write(replace != null ? replace : text[i]);
+  }
+
+  return result == null ? text : result.toString();
+}
+
+/** Iterates through an infinite sequence, starting from zero. */
+class IntIterator implements Iterator<int> {
+  int _next = -1;
+
+  int get current => _next < 0 ? null : _next;
+
+  bool moveNext() {
+    _next++;
+    return true;
+  }
+}