Time Zone data loader

- Use CountryZonesFinder to provide time zone id and region-to-timezone
  mapping, where the underlying data is updatable through an unbundled time zone
  data app in some devices.

Bug: 73952488
Bug: 72144448
Test: m RunSettingsRoboTests
Change-Id: I2e01e167c48987ebb98d4881a1a528d16dd82944

src/com/android/settings/datetime/timezone/model/TimeZoneData.java

@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2018 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 com.android.settings.datetime.timezone.model;
+
+import android.support.annotation.VisibleForTesting;
+
+import libcore.util.CountryTimeZones;
+import libcore.util.CountryZonesFinder;
+import libcore.util.TimeZoneFinder;
+
+import java.lang.ref.WeakReference;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Locale;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+/**
+ * Wrapper of CountryZonesFinder to normalize the country code and only show the regions that are
+ * has time zone shown in the time zone picker.
+ * The constructor reads the data from underlying file, and this means it should not be called
+ * from the UI thread.
+ */
+public class TimeZoneData {
+
+    private static WeakReference<TimeZoneData> sCache = null;
+
+    private final CountryZonesFinder mCountryZonesFinder;
+    private final Set<String> mRegionIds;
+
+    public static synchronized TimeZoneData getInstance() {
+        TimeZoneData data = sCache == null ? null : sCache.get();
+        if (data != null) {
+            return data;
+        }
+        data = new TimeZoneData();
+        sCache = new WeakReference<>(data);
+        return data;
+    }
+
+    public TimeZoneData() {
+        this(TimeZoneFinder.getInstance().getCountryZonesFinder());
+    }
+
+    @VisibleForTesting
+    TimeZoneData(CountryZonesFinder countryZonesFinder) {
+        mCountryZonesFinder = countryZonesFinder;
+        mRegionIds = getNormalizedRegionIds(mCountryZonesFinder.lookupAllCountryIsoCodes());
+    }
+
+    public Set<String> getRegionIds() {
+        return mRegionIds;
+    }
+
+    public Set<String> lookupCountryCodesForZoneId(String tzId) {
+        if (tzId == null) {
+            return Collections.emptySet();
+        }
+        return mCountryZonesFinder.lookupCountryTimeZonesForZoneId(tzId).stream()
+                .filter(countryTimeZones ->
+                    countryTimeZones.getTimeZoneMappings().stream()
+                            .anyMatch(mapping ->
+                                    mapping.timeZoneId.equals(tzId) && mapping.showInPicker))
+                .map(countryTimeZones -> normalizeRegionId(countryTimeZones.getCountryIso()))
+                .collect(Collectors.toSet());
+    }
+
+    public FilteredCountryTimeZones lookupCountryTimeZones(String regionId) {
+        CountryTimeZones finder = regionId == null ? null
+                : mCountryZonesFinder.lookupCountryTimeZones(regionId);
+       return finder == null ? null : new FilteredCountryTimeZones(finder);
+    }
+
+    private static Set<String> getNormalizedRegionIds(List<String> regionIds) {
+        final Set<String> result = new HashSet<>(regionIds.size());
+        for (String regionId : regionIds) {
+            result.add(normalizeRegionId(regionId));
+        }
+        return Collections.unmodifiableSet(result);
+    }
+
+    // Uppercase ASCII is normalized for the purpose of using ICU API
+    public static String normalizeRegionId(String regionId) {
+        return regionId == null ? null : regionId.toUpperCase(Locale.US);
+    }
+}