From 9aa7b74a7a64c37c1cc7bc42dc643c8916ac94fb Mon Sep 17 00:00:00 2001
From: Neil Fuller <nfuller@google.com>
Date: Mon, 17 Jun 2019 11:40:35 +0100
Subject: [PATCH] Convert some users of Time.format() to an alt.

Convert some frameworks/base/ users of android.text.format.Time.format()
to use calculations based on java.time instead. This avoids future
Y2038 issues associated with Time. A TimeMigrationUtils method is
added that has similar localization behavior to Time's format() method.

This commit only contains a replacement for basic formatting usecases.
Later commits can handle more complex usecases.

The only case that modifies the format is the changes to
CalendarContract.java: the pattern used there was unusual and only
used in logging/debug logic which was switched off by default.

Bug: 16550209
Test: build / boot / treehugger
Test: atest FrameworksCoreTests:android.text.format.TimeMigrationUtilsTest
Change-Id: Ib142979858012bb766b4c107d41a21b0324de506
---
 .../android/provider/CalendarContract.java    |   8 +-
 .../android/text/format/TimeFormatter.java    |  69 +++++++++-
 .../text/format/TimeMigrationUtils.java       |  40 ++++++
 .../text/format/TimeMigrationUtilsTest.java   | 120 ++++++++++++++++++
 .../android/server/DropBoxManagerService.java |   6 +-
 .../android/server/content/SyncManager.java   |  10 +-
 .../server/job/controllers/JobStatus.java     |  10 +-
 .../android/server/pm/ShortcutService.java    |   6 +-
 8 files changed, 235 insertions(+), 34 deletions(-)
 create mode 100644 core/java/android/text/format/TimeMigrationUtils.java
 create mode 100644 core/tests/coretests/src/android/text/format/TimeMigrationUtilsTest.java

diff --git a/core/java/android/provider/CalendarContract.java b/core/java/android/provider/CalendarContract.java
index 2f68eb475e7a6..d862d6022154b 100644
--- a/core/java/android/provider/CalendarContract.java
+++ b/core/java/android/provider/CalendarContract.java
@@ -40,7 +40,7 @@ import android.database.DatabaseUtils;
 import android.net.Uri;
 import android.os.RemoteException;
 import android.text.format.DateUtils;
-import android.text.format.Time;
+import android.text.format.TimeMigrationUtils;
 import android.util.Log;
 
 import com.android.internal.util.Preconditions;
@@ -1680,7 +1680,7 @@ public final class CalendarContract {
      * <h3>Writing to Events</h3> There are further restrictions on all Updates
      * and Inserts in the Events table:
      * <ul>
-     * <li>If allDay is set to 1 eventTimezone must be {@link Time#TIMEZONE_UTC}
+     * <li>If allDay is set to 1 eventTimezone must be "UTC"
      * and the time must correspond to a midnight boundary.</li>
      * <li>Exceptions are not allowed to recur. If rrule or rdate is not empty,
      * original_id and original_sync_id must be empty.</li>
@@ -2608,9 +2608,7 @@ public final class CalendarContract {
         @UnsupportedAppUsage
         public static void scheduleAlarm(Context context, AlarmManager manager, long alarmTime) {
             if (DEBUG) {
-                Time time = new Time();
-                time.set(alarmTime);
-                String schedTime = time.format(" %a, %b %d, %Y %I:%M%P");
+                String schedTime = TimeMigrationUtils.formatMillisWithFixedFormat(alarmTime);
                 Log.d(TAG, "Schedule alarm at " + alarmTime + " " + schedTime);
             }
 
diff --git a/core/java/android/text/format/TimeFormatter.java b/core/java/android/text/format/TimeFormatter.java
index 5a14092c95a85..f7fd89d7d819f 100644
--- a/core/java/android/text/format/TimeFormatter.java
+++ b/core/java/android/text/format/TimeFormatter.java
@@ -26,6 +26,9 @@ import libcore.icu.LocaleData;
 import libcore.util.ZoneInfo;
 
 import java.nio.CharBuffer;
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
 import java.util.Formatter;
 import java.util.Locale;
 import java.util.TimeZone;
@@ -85,6 +88,59 @@ class TimeFormatter {
         }
     }
 
+    /**
+     * The implementation of {@link TimeMigrationUtils#formatMillisWithFixedFormat(long)} for
+     * 2038-safe formatting with the pattern "%Y-%m-%d %H:%M:%S" and including the historic
+     * incorrect digit localization behavior.
+     */
+    String formatMillisWithFixedFormat(long timeMillis) {
+        // This method is deliberately not a general purpose replacement for
+        // format(String, ZoneInfo.WallTime, ZoneInfo): It hard-codes the pattern used; many of the
+        // pattern characters supported by Time.format() have unusual behavior which would make
+        // using java.time.format or similar packages difficult. It would be a lot of work to share
+        // behavior and many internal Android usecases can be covered by this common pattern
+        // behavior.
+
+        // No need to worry about overflow / underflow: long millis is representable by Instant and
+        // LocalDateTime with room to spare.
+        Instant instant = Instant.ofEpochMilli(timeMillis);
+
+        // Date/times are calculated in the current system default time zone.
+        LocalDateTime localDateTime = LocalDateTime.ofInstant(instant, ZoneId.systemDefault());
+
+        // You'd think it would be as simple as:
+        // DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss", locale);
+        // return formatter.format(localDateTime);
+        // but we retain Time's behavior around digits.
+
+        StringBuilder stringBuilder = new StringBuilder(19);
+
+        // This effectively uses the US locale because number localization is handled separately
+        // (see below).
+        stringBuilder.append(localDateTime.getYear());
+        stringBuilder.append('-');
+        append2DigitNumber(stringBuilder, localDateTime.getMonthValue());
+        stringBuilder.append('-');
+        append2DigitNumber(stringBuilder, localDateTime.getDayOfMonth());
+        stringBuilder.append(' ');
+        append2DigitNumber(stringBuilder, localDateTime.getHour());
+        stringBuilder.append(':');
+        append2DigitNumber(stringBuilder, localDateTime.getMinute());
+        stringBuilder.append(':');
+        append2DigitNumber(stringBuilder, localDateTime.getSecond());
+
+        String result = stringBuilder.toString();
+        return localizeDigits(result);
+    }
+
+    /** Zero-pads value as needed to achieve a 2-digit number. */
+    private static void append2DigitNumber(StringBuilder builder, int value) {
+        if (value < 10) {
+            builder.append('0');
+        }
+        builder.append(value);
+    }
+
     /**
      * Format the specified {@code wallTime} using {@code pattern}. The output is returned.
      */
@@ -99,12 +155,9 @@ class TimeFormatter {
 
             formatInternal(pattern, wallTime, zoneInfo);
             String result = stringBuilder.toString();
-            // This behavior is the source of a bug since some formats are defined as being
-            // in ASCII and not localized.
-            if (localeData.zeroDigit != '0') {
-                result = localizeDigits(result);
-            }
-            return result;
+            // The localizeDigits() behavior is the source of a bug since some formats are defined
+            // as being in ASCII and not localized.
+            return localizeDigits(result);
         } finally {
             outputBuilder = null;
             numberFormatter = null;
@@ -112,6 +165,10 @@ class TimeFormatter {
     }
 
     private String localizeDigits(String s) {
+        if (localeData.zeroDigit == '0') {
+            return s;
+        }
+
         int length = s.length();
         int offsetToLocalizedDigits = localeData.zeroDigit - '0';
         StringBuilder result = new StringBuilder(length);
diff --git a/core/java/android/text/format/TimeMigrationUtils.java b/core/java/android/text/format/TimeMigrationUtils.java
new file mode 100644
index 0000000000000..17bac8d67b266
--- /dev/null
+++ b/core/java/android/text/format/TimeMigrationUtils.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * 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.
+ */
+package android.text.format;
+
+/**
+ * Logic to ease migration away from {@link Time} in Android internal code. {@link Time} is
+ * afflicted by the Y2038 issue and deprecated. The methods here are intended to allow minimal
+ * changes to classes that use {@link Time} for common behavior.
+ *
+ * @hide
+ */
+public class TimeMigrationUtils {
+
+    private TimeMigrationUtils() {}
+
+    /**
+     * A Y2038-safe replacement for various users of the {@link Time#format(String)} with the
+     * pattern "%Y-%m-%d %H:%M:%S". Note, this method retains the unusual localization behavior
+     * originally implemented by Time, which can lead to non-latin numbers being produced if the
+     * default locale does not use latin numbers.
+     */
+    public static String formatMillisWithFixedFormat(long timeMillis) {
+        // Delegate to TimeFormatter so that the unusual localization / threading behavior can be
+        // reused.
+        return new TimeFormatter().formatMillisWithFixedFormat(timeMillis);
+    }
+}
diff --git a/core/tests/coretests/src/android/text/format/TimeMigrationUtilsTest.java b/core/tests/coretests/src/android/text/format/TimeMigrationUtilsTest.java
new file mode 100644
index 0000000000000..b605520c659d5
--- /dev/null
+++ b/core/tests/coretests/src/android/text/format/TimeMigrationUtilsTest.java
@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * 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.
+ */
+
+package android.text.format;
+
+import static org.junit.Assert.assertEquals;
+
+import android.platform.test.annotations.Presubmit;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.util.Locale;
+import java.util.TimeZone;
+
+@Presubmit
+@SmallTest
+@RunWith(AndroidJUnit4.class)
+public class TimeMigrationUtilsTest {
+
+    private static final int ONE_DAY_IN_SECONDS = 24 * 60 * 60;
+
+    private Locale mDefaultLocale;
+    private TimeZone mDefaultTimeZone;
+
+    @Before
+    public void setUp() {
+        mDefaultLocale = Locale.getDefault();
+        mDefaultTimeZone = TimeZone.getDefault();
+    }
+
+    @After
+    public void tearDown() {
+        Locale.setDefault(mDefaultLocale);
+        TimeZone.setDefault(mDefaultTimeZone);
+    }
+
+    @Test
+    public void formatMillisWithFixedFormat_fixes2038Issue() {
+        Locale.setDefault(Locale.UK);
+        TimeZone.setDefault(TimeZone.getTimeZone("UTC"));
+
+        // The following cannot be represented properly using Time because they are outside of the
+        // supported range.
+        long y2038Issue1 = (((long) Integer.MIN_VALUE) - ONE_DAY_IN_SECONDS) * 1000L;
+        assertEquals(
+                "1901-12-12 20:45:52", TimeMigrationUtils.formatMillisWithFixedFormat(y2038Issue1));
+        long y2038Issue2 = (((long) Integer.MAX_VALUE) + ONE_DAY_IN_SECONDS) * 1000L;
+        assertEquals(
+                "2038-01-20 03:14:07", TimeMigrationUtils.formatMillisWithFixedFormat(y2038Issue2));
+    }
+
+    /**
+     * Compares TimeMigrationUtils.formatSimpleDateTime() with the code it is replacing.
+     */
+    @Test
+    public void formatMillisAsDateTime_matchesOldBehavior() {
+        // A selection of interesting locales.
+        Locale[] locales = new Locale[] {
+                Locale.US,
+                Locale.UK,
+                Locale.FRANCE,
+                Locale.JAPAN,
+                Locale.CHINA,
+                // Android supports RTL locales like arabic and arabic with latin numbers.
+                Locale.forLanguageTag("ar-AE"),
+                Locale.forLanguageTag("ar-AE-u-nu-latn"),
+        };
+        // A selection of interesting time zones.
+        String[] timeZoneIds = new String[] {
+                "UTC", "Europe/London", "America/New_York", "America/Los_Angeles", "Asia/Shanghai",
+        };
+        // Some arbitrary times when the two formatters should agree.
+        long[] timesMillis = new long[] {
+                System.currentTimeMillis(),
+                0,
+                // The Time class only works in 32-bit range, the replacement works beyond that. To
+                // avoid messing around with offsets and complicating the test, below there are a
+                // day after / before the known limits.
+                (Integer.MIN_VALUE + ONE_DAY_IN_SECONDS) * 1000L,
+                (Integer.MAX_VALUE - ONE_DAY_IN_SECONDS) * 1000L,
+        };
+
+        for (Locale locale : locales) {
+            Locale.setDefault(locale);
+            for (String timeZoneId : timeZoneIds) {
+                TimeZone timeZone = TimeZone.getTimeZone(timeZoneId);
+                TimeZone.setDefault(timeZone);
+                for (long timeMillis : timesMillis) {
+                    Time time = new Time();
+                    time.set(timeMillis);
+                    String oldResult = time.format("%Y-%m-%d %H:%M:%S");
+                    String newResult = TimeMigrationUtils.formatMillisWithFixedFormat(timeMillis);
+                    assertEquals(
+                            "locale=" + locale + ", timeZoneId=" + timeZoneId
+                                    + ", timeMillis=" + timeMillis,
+                            oldResult, newResult);
+                }
+            }
+        }
+    }
+}
diff --git a/services/core/java/com/android/server/DropBoxManagerService.java b/services/core/java/com/android/server/DropBoxManagerService.java
index 9dead161390f5..aeb3e7fd94de5 100644
--- a/services/core/java/com/android/server/DropBoxManagerService.java
+++ b/services/core/java/com/android/server/DropBoxManagerService.java
@@ -41,7 +41,7 @@ import android.os.SystemClock;
 import android.os.UserHandle;
 import android.provider.Settings;
 import android.text.TextUtils;
-import android.text.format.Time;
+import android.text.format.TimeMigrationUtils;
 import android.util.ArrayMap;
 import android.util.ArraySet;
 import android.util.Slog;
@@ -582,11 +582,9 @@ public final class DropBoxManagerService extends SystemService {
         }
 
         int numFound = 0, numArgs = searchArgs.size();
-        Time time = new Time();
         out.append("\n");
         for (EntryFile entry : mAllFiles.contents) {
-            time.set(entry.timestampMillis);
-            String date = time.format("%Y-%m-%d %H:%M:%S");
+            String date = TimeMigrationUtils.formatMillisWithFixedFormat(entry.timestampMillis);
             boolean match = true;
             for (int i = 0; i < numArgs && match; i++) {
                 String arg = searchArgs.get(i);
diff --git a/services/core/java/com/android/server/content/SyncManager.java b/services/core/java/com/android/server/content/SyncManager.java
index fa8c48bdc7f78..a89daff2d3bb0 100644
--- a/services/core/java/com/android/server/content/SyncManager.java
+++ b/services/core/java/com/android/server/content/SyncManager.java
@@ -86,7 +86,7 @@ import android.os.UserHandle;
 import android.os.UserManager;
 import android.os.WorkSource;
 import android.provider.Settings;
-import android.text.format.Time;
+import android.text.format.TimeMigrationUtils;
 import android.util.EventLog;
 import android.util.Log;
 import android.util.Pair;
@@ -1987,9 +1987,7 @@ public class SyncManager {
         if (time == 0) {
             return "N/A";
         }
-        Time tobj = new Time();
-        tobj.set(time);
-        return tobj.format("%Y-%m-%d %H:%M:%S");
+        return TimeMigrationUtils.formatMillisWithFixedFormat(time);
     }
 
     private final static Comparator<SyncOperation> sOpDumpComparator = (op1, op2) -> {
@@ -2555,9 +2553,7 @@ public class SyncManager {
                     accountKey = "Unknown";
                 }
                 final long elapsedTime = item.elapsedTime;
-                final Time time = new Time();
                 final long eventTime = item.eventTime;
-                time.set(eventTime);
 
                 final String key = authorityName + "/" + accountKey;
                 final Long lastEventTime = lastTimeMap.get(key);
@@ -2622,9 +2618,7 @@ public class SyncManager {
                     authorityName = "Unknown";
                     accountKey = "Unknown";
                 }
-                final Time time = new Time();
                 final long eventTime = item.eventTime;
-                time.set(eventTime);
 
                 pw.printf("  #%-3d: %s %8s ",
                         i + 1,
diff --git a/services/core/java/com/android/server/job/controllers/JobStatus.java b/services/core/java/com/android/server/job/controllers/JobStatus.java
index eb5d472f7fbc3..e655b35d930fe 100644
--- a/services/core/java/com/android/server/job/controllers/JobStatus.java
+++ b/services/core/java/com/android/server/job/controllers/JobStatus.java
@@ -29,7 +29,7 @@ import android.net.Network;
 import android.net.Uri;
 import android.os.RemoteException;
 import android.os.UserHandle;
-import android.text.format.Time;
+import android.text.format.TimeMigrationUtils;
 import android.util.ArraySet;
 import android.util.Pair;
 import android.util.Slog;
@@ -1643,17 +1643,13 @@ public final class JobStatus {
         if (numFailures != 0) {
             pw.print(prefix); pw.print("Num failures: "); pw.println(numFailures);
         }
-        final Time t = new Time();
-        final String format = "%Y-%m-%d %H:%M:%S";
         if (mLastSuccessfulRunTime != 0) {
             pw.print(prefix); pw.print("Last successful run: ");
-            t.set(mLastSuccessfulRunTime);
-            pw.println(t.format(format));
+            pw.println(TimeMigrationUtils.formatMillisWithFixedFormat(mLastSuccessfulRunTime));
         }
         if (mLastFailedRunTime != 0) {
             pw.print(prefix); pw.print("Last failed run: ");
-            t.set(mLastFailedRunTime);
-            pw.println(t.format(format));
+            pw.println(TimeMigrationUtils.formatMillisWithFixedFormat(mLastFailedRunTime));
         }
     }
 
diff --git a/services/core/java/com/android/server/pm/ShortcutService.java b/services/core/java/com/android/server/pm/ShortcutService.java
index 2d8a2acd575f9..ebba128b5f286 100644
--- a/services/core/java/com/android/server/pm/ShortcutService.java
+++ b/services/core/java/com/android/server/pm/ShortcutService.java
@@ -79,7 +79,7 @@ import android.os.SystemClock;
 import android.os.UserHandle;
 import android.os.UserManagerInternal;
 import android.text.TextUtils;
-import android.text.format.Time;
+import android.text.format.TimeMigrationUtils;
 import android.util.ArraySet;
 import android.util.AtomicFile;
 import android.util.KeyValueListParser;
@@ -3981,9 +3981,7 @@ public class ShortcutService extends IShortcutService.Stub {
     }
 
     static String formatTime(long time) {
-        Time tobj = new Time();
-        tobj.set(time);
-        return tobj.format("%Y-%m-%d %H:%M:%S");
+        return TimeMigrationUtils.formatMillisWithFixedFormat(time);
     }
 
     private void dumpCurrentTime(PrintWriter pw) {