Use ICU for relative time formatting

Rewrite the DateUtils' relative time formatting APIs
(getRelativeTimeSpanString, getRelativeDateTimeString) to use ICU ones.
Two APIs that take withPreposition parameter are not changed. Because
(a) ICU doesn't provide functionality to format preposition; (b) They
are not really computing relative time but instead calling
formatDateRange() to get the absolute time/date string.

Bug: 19146457
Bug: 5252772
Change-Id: Iea8d699d63cc4438513910da66d038912e44fb8d

1 files changed, 15 insertions, 139 deletions

diff --git a/core/java/android/text/format/DateUtils.java b/core/java/android/text/format/DateUtils.java
index d0ed871..ac98e8a 100644
--- a/core/java/android/text/format/DateUtils.java
+++ b/core/java/android/text/format/DateUtils.java
@@ -28,9 +28,11 @@ import java.util.Date;
 import java.util.Formatter;
 import java.util.GregorianCalendar;
 import java.util.Locale;
+import java.util.TimeZone;
 
 import libcore.icu.DateIntervalFormat;
 import libcore.icu.LocaleData;
+import libcore.icu.RelativeDateTimeFormatter;
 
 /**
  * This class contains various date-related utilities for creating text for things like
@@ -242,6 +244,8 @@ public class DateUtils
 
     /**
      * Returns a string describing the elapsed time since startTime.
+     * <p>
+     * The minimum timespan to report is set to {@link #MINUTE_IN_MILLIS}.
      * @param startTime some time in the past.
      * @return a String object containing the elapsed time.
      * @see #getRelativeTimeSpanString(long, long, long)
@@ -289,69 +293,8 @@ public class DateUtils
      */
     public static CharSequence getRelativeTimeSpanString(long time, long now, long minResolution,
             int flags) {
-        Resources r = Resources.getSystem();
-        boolean abbrevRelative = (flags & (FORMAT_ABBREV_RELATIVE | FORMAT_ABBREV_ALL)) != 0;
-
-        boolean past = (now >= time);
-        long duration = Math.abs(now - time);
-
-        int resId;
-        long count;
-        if (duration < MINUTE_IN_MILLIS && minResolution < MINUTE_IN_MILLIS) {
-            count = duration / SECOND_IN_MILLIS;
-            if (past) {
-                if (abbrevRelative) {
-                    resId = com.android.internal.R.plurals.abbrev_num_seconds_ago;
-                } else {
-                    resId = com.android.internal.R.plurals.num_seconds_ago;
-                }
-            } else {
-                if (abbrevRelative) {
-                    resId = com.android.internal.R.plurals.abbrev_in_num_seconds;
-                } else {
-                    resId = com.android.internal.R.plurals.in_num_seconds;
-                }
-            }
-        } else if (duration < HOUR_IN_MILLIS && minResolution < HOUR_IN_MILLIS) {
-            count = duration / MINUTE_IN_MILLIS;
-            if (past) {
-                if (abbrevRelative) {
-                    resId = com.android.internal.R.plurals.abbrev_num_minutes_ago;
-                } else {
-                    resId = com.android.internal.R.plurals.num_minutes_ago;
-                }
-            } else {
-                if (abbrevRelative) {
-                    resId = com.android.internal.R.plurals.abbrev_in_num_minutes;
-                } else {
-                    resId = com.android.internal.R.plurals.in_num_minutes;
-                }
-            }
-        } else if (duration < DAY_IN_MILLIS && minResolution < DAY_IN_MILLIS) {
-            count = duration / HOUR_IN_MILLIS;
-            if (past) {
-                if (abbrevRelative) {
-                    resId = com.android.internal.R.plurals.abbrev_num_hours_ago;
-                } else {
-                    resId = com.android.internal.R.plurals.num_hours_ago;
-                }
-            } else {
-                if (abbrevRelative) {
-                    resId = com.android.internal.R.plurals.abbrev_in_num_hours;
-                } else {
-                    resId = com.android.internal.R.plurals.in_num_hours;
-                }
-            }
-        } else if (duration < WEEK_IN_MILLIS && minResolution < WEEK_IN_MILLIS) {
-            return getRelativeDayString(r, time, now);
-        } else {
-            // We know that we won't be showing the time, so it is safe to pass
-            // in a null context.
-            return formatDateRange(null, time, time, flags);
-        }
-
-        String format = r.getQuantityString(resId, (int) count);
-        return String.format(format, count);
+        return RelativeDateTimeFormatter.getRelativeTimeSpanString(Locale.getDefault(),
+                TimeZone.getDefault(), time, now, minResolution, flags);
     }
 
     /**
@@ -360,8 +303,8 @@ public class DateUtils
      * <p>
      * Example output strings for the US date format.
      * <ul>
-     * <li>3 mins ago, 10:15 AM</li>
-     * <li>yesterday, 12:20 PM</li>
+     * <li>3 min. ago, 10:15 AM</li>
+     * <li>Yesterday, 12:20 PM</li>
      * <li>Dec 12, 4:12 AM</li>
      * <li>11/14/2007, 8:20 AM</li>
      * </ul>
@@ -374,86 +317,19 @@ public class DateUtils
      * @param transitionResolution the elapsed time (in milliseconds) at which
      *            to stop reporting relative measurements. Elapsed times greater
      *            than this resolution will default to normal date formatting.
-     *            For example, will transition from "6 days ago" to "Dec 12"
+     *            For example, will transition from "7 days ago" to "Dec 12"
      *            when using {@link #WEEK_IN_MILLIS}.
      */
     public static CharSequence getRelativeDateTimeString(Context c, long time, long minResolution,
             long transitionResolution, int flags) {
-        Resources r = Resources.getSystem();
-
-        long now = System.currentTimeMillis();
-        long duration = Math.abs(now - time);
-
-        // getRelativeTimeSpanString() doesn't correctly format relative dates
-        // above a week or exact dates below a day, so clamp
-        // transitionResolution as needed.
-        if (transitionResolution > WEEK_IN_MILLIS) {
-            transitionResolution = WEEK_IN_MILLIS;
-        } else if (transitionResolution < DAY_IN_MILLIS) {
-            transitionResolution = DAY_IN_MILLIS;
-        }
-
-        CharSequence timeClause = formatDateRange(c, time, time, FORMAT_SHOW_TIME);
-
-        String result;
-        if (duration < transitionResolution) {
-            CharSequence relativeClause = getRelativeTimeSpanString(time, now, minResolution, flags);
-            result = r.getString(com.android.internal.R.string.relative_time, relativeClause, timeClause);
-        } else {
-            CharSequence dateClause = getRelativeTimeSpanString(c, time, false);
-            result = r.getString(com.android.internal.R.string.date_time, dateClause, timeClause);
-        }
-
-        return result;
-    }
-
-    /**
-     * Returns a string describing a day relative to the current day. For example if the day is
-     * today this function returns "Today", if the day was a week ago it returns "7 days ago", and
-     * if the day is in 2 weeks it returns "in 14 days".
-     *
-     * @param r the resources
-     * @param day the relative day to describe in UTC milliseconds
-     * @param today the current time in UTC milliseconds
-     */
-    private static final String getRelativeDayString(Resources r, long day, long today) {
-        Locale locale = r.getConfiguration().locale;
-        if (locale == null) {
-            locale = Locale.getDefault();
-        }
-
-        // TODO: use TimeZone.getOffset instead.
-        Time startTime = new Time();
-        startTime.set(day);
-        int startDay = Time.getJulianDay(day, startTime.gmtoff);
-
-        Time currentTime = new Time();
-        currentTime.set(today);
-        int currentDay = Time.getJulianDay(today, currentTime.gmtoff);
-
-        int days = Math.abs(currentDay - startDay);
-        boolean past = (today > day);
-
-        // TODO: some locales name other days too, such as de_DE's "Vorgestern" (today - 2).
-        if (days == 1) {
-            if (past) {
-                return LocaleData.get(locale).yesterday;
-            } else {
-                return LocaleData.get(locale).tomorrow;
-            }
-        } else if (days == 0) {
-            return LocaleData.get(locale).today;
-        }
-
-        int resId;
-        if (past) {
-            resId = com.android.internal.R.plurals.num_days_ago;
-        } else {
-            resId = com.android.internal.R.plurals.in_num_days;
+        // Same reason as in formatDateRange() to explicitly indicate 12- or 24-hour format.
+        if ((flags & (FORMAT_SHOW_TIME | FORMAT_12HOUR | FORMAT_24HOUR)) == FORMAT_SHOW_TIME) {
+            flags |= DateFormat.is24HourFormat(c) ? FORMAT_24HOUR : FORMAT_12HOUR;
         }
 
-        String format = r.getQuantityString(resId, days);
-        return String.format(format, days);
+        return RelativeDateTimeFormatter.getRelativeDateTimeString(Locale.getDefault(),
+                TimeZone.getDefault(), time, System.currentTimeMillis(), minResolution,
+                transitionResolution, flags);
     }
 
     private static void initFormatStrings() {