Roll Observatory packages and add a roll script

quiver/lib/src/time/clock.dart

-// Copyright 2013 Google Inc. All Rights Reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-part of quiver.time;
-
-/// Returns current time.
-typedef DateTime TimeFunction();
-
-/// Return current system time.
-DateTime systemTime() => new DateTime.now();
-
-/// Days in a month. This array uses 1-based month numbers, i.e. January is
-/// the 1-st element in the array, not the 0-th.
-const _DAYS_IN_MONTH =
-    const [ 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 ];
-
-int _daysInMonth(int year, int month) => (month == DateTime.FEBRUARY &&
-    _isLeapYear(year)) ? 29 : _DAYS_IN_MONTH[month];
-
-bool _isLeapYear(int year) =>
-    (year % 4 == 0) && ((year % 100 != 0) || (year % 400 == 0));
-
-/// Takes a [date] that may be outside the allowed range of dates for a given
-/// [month] in a given [year] and returns the closest date that is within the
-/// allowed range.
-///
-/// For example:
-///
-/// February 31, 2013 => February 28, 2013
-///
-/// When jumping from month to month or from leap year to common year we may
-/// end up in a month that has fewer days than the month we are jumping from.
-/// In that case it is impossible to preserve the exact date. So we "clamp" the
-/// date value to fit within the month. For example, jumping from March 31 one
-/// month back takes us to February 28 (or 29 during a leap year), as February
-/// doesn't have 31-st date.
-int _clampDate(int date, int year, int month) =>
-    date.clamp(1, _daysInMonth(year, month));
-
-/// Provides points in time relative to the current point in time, for example:
-/// now, 2 days ago, 4 weeks from now, etc.
-///
-/// This class is designed with testability in mind. The current point in time
-/// (or [now()]) is defined by a [TimeFunction]. By supplying your own time
-/// function or by using fixed clock (see constructors), you can control
-/// exactly what time a [Clock] returns and base your test expectations on
-/// that. See specific constructors for how to supply time functions.
-class Clock {
-  final TimeFunction _time;
-
-  /// Creates a clock based on the given [timeFunc].
-  ///
-  /// If [timeFunc] is not provided, creates [Clock] based on system clock.
-  ///
-  /// Custom [timeFunc] can be useful in unit-tests. For example, you might
-  /// want to control what time it is now and set date and time expectations in
-  /// your test cases.
-  const Clock([TimeFunction timeFunc = systemTime]) : _time = timeFunc;
-
-  /// Creates [Clock] that returns fixed [time] value. Useful in unit-tests.
-  Clock.fixed(DateTime time) : _time = (() => time);
-
-  /// Returns current time.
-  DateTime now() => _time();
-
-  /// Returns the point in time [Duration] amount of time ago.
-  DateTime agoBy(Duration duration) => now().subtract(duration);
-
-  /// Returns the point in time [Duration] amount of time from now.
-  DateTime fromNowBy(Duration duration) => now().add(duration);
-
-  /// Returns the point in time that's given amount of time ago. The
-  /// amount of time is the sum of individual parts. Parts are compatible with
-  /// ones defined in [Duration].
-  DateTime ago({int days: 0, int hours: 0, int minutes: 0, int seconds: 0,
-      int milliseconds: 0, int microseconds: 0}) => agoBy(new Duration(
-          days: days,
-          hours: hours,
-          minutes: minutes,
-          seconds: seconds,
-          milliseconds: milliseconds,
-          microseconds: microseconds));
-
-  /// Returns the point in time that's given amount of time from now. The
-  /// amount of time is the sum of individual parts. Parts are compatible with
-  /// ones defined in [Duration].
-  DateTime fromNow({int days: 0, int hours: 0, int minutes: 0, int seconds: 0,
-      int milliseconds: 0, int microseconds: 0}) => fromNowBy(new Duration(
-          days: days,
-          hours: hours,
-          minutes: minutes,
-          seconds: seconds,
-          milliseconds: milliseconds,
-          microseconds: microseconds));
-
-  /// Return the point in time [micros] microseconds ago.
-  DateTime microsAgo(int micros) => ago(microseconds: micros);
-
-  /// Return the point in time [micros] microseconds from now.
-  DateTime microsFromNow(int micros) => fromNow(microseconds: micros);
-
-  /// Return the point in time [millis] milliseconds ago.
-  DateTime millisAgo(int millis) => ago(milliseconds: millis);
-
-  /// Return the point in time [millis] milliseconds from now.
-  DateTime millisFromNow(int millis) => fromNow(milliseconds: millis);
-
-  /// Return the point in time [seconds] ago.
-  DateTime secondsAgo(int seconds) => ago(seconds: seconds);
-
-  /// Return the point in time [seconds] from now.
-  DateTime secondsFromNow(int seconds) => fromNow(seconds: seconds);
-
-  /// Return the point in time [minutes] ago.
-  DateTime minutesAgo(int minutes) => ago(minutes: minutes);
-
-  /// Return the point in time [minutes] from now.
-  DateTime minutesFromNow(int minutes) => fromNow(minutes: minutes);
-
-  /// Return the point in time [hours] ago.
-  DateTime hoursAgo(int hours) => ago(hours: hours);
-
-  /// Return the point in time [hours] from now.
-  DateTime hoursFromNow(int hours) => fromNow(hours: hours);
-
-  /// Return the point in time [days] ago.
-  DateTime daysAgo(int days) => ago(days: days);
-
-  /// Return the point in time [days] from now.
-  DateTime daysFromNow(int days) => fromNow(days: days);
-
-  /// Return the point in time [weeks] ago.
-  DateTime weeksAgo(int weeks) => ago(days: 7 * weeks);
-
-  /// Return the point in time [weeks] from now.
-  DateTime weeksFromNow(int weeks) => fromNow(days: 7 * weeks);
-
-  /// Return the point in time [months] ago on the same date.
-  DateTime monthsAgo(int months) {
-    var time = now();
-    var m = (time.month - months - 1) % 12 + 1;
-    var y = time.year - (months + 12 - time.month) ~/ 12;
-    var d = _clampDate(time.day, y, m);
-    return new DateTime(
-        y, m, d, time.hour, time.minute, time.second, time.millisecond);
-  }
-
-  /// Return the point in time [months] from now on the same date.
-  DateTime monthsFromNow(int months) {
-    var time = now();
-    var m = (time.month + months - 1) % 12 + 1;
-    var y = time.year + (months + time.month - 1) ~/ 12;
-    var d = _clampDate(time.day, y, m);
-    return new DateTime(
-        y, m, d, time.hour, time.minute, time.second, time.millisecond);
-  }
-
-  /// Return the point in time [years] ago on the same date.
-  DateTime yearsAgo(int years) {
-    var time = now();
-    var y = time.year - years;
-    var d = _clampDate(time.day, y, time.month);
-    return new DateTime(y, time.month, d, time.hour, time.minute, time.second,
-        time.millisecond);
-  }
-
-  /// Return the point in time [years] from now on the same date.
-  DateTime yearsFromNow(int years) => yearsAgo(-years);
-}