Stop running pub get at gclient sync time and fix build bugs

mojo/public/dart/third_party/barback/lib/src/utils.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.
+
+library barback.utils;
+
+import 'dart:async';
+import 'dart:typed_data';
+
+import 'package:stack_trace/stack_trace.dart';
+
+/// A class that represents a value or an error.
+class Fallible<E> {
+  /// Whether [this] has a [value], as opposed to an [error].
+  final bool hasValue;
+
+  /// Whether [this] has an [error], as opposed to a [value].
+  bool get hasError => !hasValue;
+
+  /// The value.
+  ///
+  /// This will be `null` if [this] has an [error].
+  final E _value;
+
+  /// The value.
+  ///
+  /// This will throw a [StateError] if [this] has an [error].
+  E get value {
+    if (hasValue) return _value;
+    throw new StateError("Fallible has no value.\n"
+        "$_error$_stackTraceSuffix");
+  }
+
+  /// The error.
+  ///
+  /// This will be `null` if [this] has a [value].
+  final _error;
+
+  /// The error.
+  ///
+  /// This will throw a [StateError] if [this] has a [value].
+  get error {
+    if (hasError) return _error;
+    throw new StateError("Fallible has no error.");
+  }
+
+  /// The stack trace for [_error].
+  ///
+  /// This will be `null` if [this] has a [value], or if no stack trace was
+  /// provided.
+  final StackTrace _stackTrace;
+
+  /// The stack trace for [error].
+  ///
+  /// This will throw a [StateError] if [this] has a [value].
+  StackTrace get stackTrace {
+    if (hasError) return _stackTrace;
+    throw new StateError("Fallible has no error.");
+  }
+
+  Fallible.withValue(this._value)
+      : _error = null,
+        _stackTrace = null,
+        hasValue = true;
+
+  Fallible.withError(this._error, [this._stackTrace])
+      : _value = null,
+        hasValue = false;
+
+  /// Returns a completed Future with the same value or error as [this].
+  Future toFuture() {
+    if (hasValue) return new Future.value(value);
+    return new Future.error(error, stackTrace);
+  }
+
+  String toString() {
+    if (hasValue) return "Fallible value: $value";
+    return "Fallible error: $error$_stackTraceSuffix";
+  }
+
+  String get _stackTraceSuffix {
+    if (stackTrace == null) return "";
+    return "\nStack trace:\n${new Chain.forTrace(_stackTrace).terse}";
+  }
+}
+
+/// Converts a number in the range [0-255] to a two digit hex string.
+///
+/// For example, given `255`, returns `ff`.
+String byteToHex(int byte) {
+  assert(byte >= 0 && byte <= 255);
+
+  const DIGITS = "0123456789abcdef";
+  return DIGITS[(byte ~/ 16) % 16] + DIGITS[byte % 16];
+}
+
+/// Returns a sentence fragment listing the elements of [iter].
+///
+/// This converts each element of [iter] to a string and separates them with
+/// commas and/or "and" where appropriate.
+String toSentence(Iterable iter) {
+  if (iter.length == 1) return iter.first.toString();
+  return iter.take(iter.length - 1).join(", ") + " and ${iter.last}";
+}
+
+/// Returns [name] if [number] is 1, or the plural of [name] otherwise.
+///
+/// By default, this just adds "s" to the end of [name] to get the plural. If
+/// [plural] is passed, that's used instead.
+String pluralize(String name, int number, {String plural}) {
+  if (number == 1) return name;
+  if (plural != null) return plural;
+  return '${name}s';
+}
+
+/// Converts [input] into a [Uint8List].
+///
+/// If [input] is a [TypedData], this just returns a view on [input].
+Uint8List toUint8List(List<int> input) {
+  if (input is Uint8List) return input;
+  if (input is TypedData) {
+    // TODO(nweiz): remove "as" when issue 11080 is fixed.
+    return new Uint8List.view((input as TypedData).buffer);
+  }
+  return new Uint8List.fromList(input);
+}
+
+/// Group the elements in [iter] by the value returned by [fn].
+///
+/// This returns a map whose keys are the return values of [fn] and whose values
+/// are lists of each element in [iter] for which [fn] returned that key.
+Map<Object, List> groupBy(Iterable iter, fn(element)) {
+  var map = {};
+  for (var element in iter) {
+    var list = map.putIfAbsent(fn(element), () => []);
+    list.add(element);
+  }
+  return map;
+}
+
+/// Flattens nested lists inside an iterable into a single list containing only
+/// non-list elements.
+List flatten(Iterable nested) {
+  var result = [];
+  helper(list) {
+    for (var element in list) {
+      if (element is List) {
+        helper(element);
+      } else {
+        result.add(element);
+      }
+    }
+  }
+  helper(nested);
+  return result;
+}
+
+/// Returns the union of all elements in each set in [sets].
+Set unionAll(Iterable<Set> sets) =>
+  sets.fold(new Set(), (union, set) => union.union(set));
+
+/// Creates a new map from [map] with new keys and values.
+///
+/// The return values of [keyFn] are used as the keys and the return values of
+/// [valueFn] are used as the values for the new map.
+Map mapMap(Map map, keyFn(key, value), valueFn(key, value)) =>
+  new Map.fromIterable(map.keys,
+      key: (key) => keyFn(key, map[key]),
+      value: (key) => valueFn(key, map[key]));
+
+/// Creates a new map from [map] with the same keys.
+///
+/// The return values of [fn] are used as the values for the new map.
+Map mapMapValues(Map map, fn(key, value)) => mapMap(map, (key, _) => key, fn);
+
+/// Creates a new map from [map] with the same keys.
+///
+/// The return values of [fn] are used as the keys for the new map.
+Map mapMapKeys(Map map, fn(key, value)) => mapMap(map, fn, (_, value) => value);
+
+/// Returns whether [set1] has exactly the same elements as [set2].
+bool setEquals(Set set1, Set set2) =>
+  set1.length == set2.length && set1.containsAll(set2);
+
+/// Merges [streams] into a single stream that emits events from all sources.
+///
+/// If [broadcast] is true, this will return a broadcast stream; otherwise, it
+/// will return a buffered stream.
+Stream mergeStreams(Iterable<Stream> streams, {bool broadcast: false}) {
+  streams = streams.toList();
+  var doneCount = 0;
+  // Use a sync stream to preserve the synchrony behavior of the input streams.
+  // If the inputs are sync, then this will be sync as well; if the inputs are
+  // async, then the events we receive will also be async, and forwarding them
+  // sync won't change that.
+  var controller = broadcast ? new StreamController.broadcast(sync: true)
+      : new StreamController(sync: true);
+
+  for (var stream in streams) {
+    stream.listen(
+        controller.add,
+        onError: controller.addError,
+        onDone: () {
+      doneCount++;
+      if (doneCount == streams.length) controller.close();
+    });
+  }
+
+  return controller.stream;
+}
+
+/// Prepends each line in [text] with [prefix]. If [firstPrefix] is passed, the
+/// first line is prefixed with that instead.
+String prefixLines(String text, {String prefix: '| ', String firstPrefix}) {
+  var lines = text.split('\n');
+  if (firstPrefix == null) {
+    return lines.map((line) => '$prefix$line').join('\n');
+  }
+
+  var firstLine = "$firstPrefix${lines.first}";
+  lines = lines.skip(1).map((line) => '$prefix$line').toList();
+  lines.insert(0, firstLine);
+  return lines.join('\n');
+}
+
+/// Returns a [Future] that completes after pumping the event queue [times]
+/// times. By default, this should pump the event queue enough times to allow
+/// any code to run, as long as it's not waiting on some external event.
+Future pumpEventQueue([int times=20]) {
+  if (times == 0) return new Future.value();
+  // We use a delayed future to allow microtask events to finish. The
+  // Future.value or Future() constructors use scheduleMicrotask themselves and
+  // would therefore not wait for microtask callbacks that are scheduled after
+  // invoking this method.
+  return new Future.delayed(Duration.ZERO, () => pumpEventQueue(times - 1));
+}
+
+/// Like `new Future`, but avoids issue 11911 by using `new Future.value` under
+/// the covers.
+// TODO(jmesserly): doc comment changed to due 14601.
+Future newFuture(callback()) => new Future.value().then((_) => callback());
+
+/// Like [Future.sync], but wraps the Future in [Chain.track] as well.
+Future syncFuture(callback()) => Chain.track(new Future.sync(callback));
+
+/// Returns a buffered stream that will emit the same values as the stream
+/// returned by [future] once [future] completes.
+///
+/// If [future] completes to an error, the return value will emit that error and
+/// then close.
+///
+/// If [broadcast] is true, a broadcast stream is returned. This assumes that
+/// the stream returned by [future] will be a broadcast stream as well.
+/// [broadcast] defaults to false.
+Stream futureStream(Future<Stream> future, {bool broadcast: false}) {
+  var subscription;
+  var controller;
+
+  future = future.catchError((e, stackTrace) {
+    // Since [controller] is synchronous, it's likely that emitting an error
+    // will cause it to be cancelled before we call close.
+    if (controller != null) controller.addError(e, stackTrace);
+    if (controller != null) controller.close();
+    controller = null;
+  });
+
+  onListen() {
+    future.then((stream) {
+      if (controller == null) return;
+      subscription = stream.listen(
+          controller.add,
+          onError: controller.addError,
+          onDone: controller.close);
+    });
+  }
+
+  onCancel() {
+    if (subscription != null) subscription.cancel();
+    subscription = null;
+    controller = null;
+  }
+
+  if (broadcast) {
+    controller = new StreamController.broadcast(
+        sync: true, onListen: onListen, onCancel: onCancel);
+  } else {
+    controller = new StreamController(
+        sync: true, onListen: onListen, onCancel: onCancel);
+  }
+  return controller.stream;
+}
+
+/// Returns a [Stream] that will emit the same values as the stream returned by
+/// [callback].
+///
+/// [callback] will only be called when the returned [Stream] gets a subscriber.
+Stream callbackStream(Stream callback()) {
+  var subscription;
+  var controller;
+  controller = new StreamController(onListen: () {
+    subscription = callback().listen(controller.add,
+        onError: controller.addError,
+        onDone: controller.close);
+  },
+      onCancel: () => subscription.cancel(),
+      onPause: () => subscription.pause(),
+      onResume: () => subscription.resume(),
+      sync: true);
+  return controller.stream;
+}
+
+/// Creates a single-subscription stream from a broadcast stream.
+///
+/// The returned stream will enqueue events from [broadcast] until a listener is
+/// attached, then pipe events to that listener.
+Stream broadcastToSingleSubscription(Stream broadcast) {
+  if (!broadcast.isBroadcast) return broadcast;
+
+  // TODO(nweiz): Implement this using a transformer when issues 18588 and 18586
+  // are fixed.
+  var subscription;
+  var controller = new StreamController(onCancel: () => subscription.cancel());
+  subscription = broadcast.listen(controller.add,
+      onError: controller.addError,
+      onDone: controller.close);
+  return controller.stream;
+}
+
+/// A regular expression to match the exception prefix that some exceptions'
+/// [Object.toString] values contain.
+final _exceptionPrefix = new RegExp(r'^([A-Z][a-zA-Z]*)?(Exception|Error): ');
+
+/// Get a string description of an exception.
+///
+/// Many exceptions include the exception class name at the beginning of their
+/// [toString], so we remove that if it exists.
+String getErrorMessage(error) =>
+  error.toString().replaceFirst(_exceptionPrefix, '');
+
+/// Returns a human-friendly representation of [duration].
+String niceDuration(Duration duration) {
+  var result = duration.inMinutes > 0 ? "${duration.inMinutes}:" : "";
+
+  var s = duration.inSeconds % 59;
+  var ms = (duration.inMilliseconds % 1000) ~/ 100;
+  return result + "$s.${ms}s";
+}