/* * Copyright 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 com.android.internal.telephony.nitz; import static android.app.timezonedetector.TelephonyTimeZoneSuggestion.createEmptySuggestion; import android.annotation.NonNull; import android.annotation.Nullable; import android.app.timezonedetector.TelephonyTimeZoneSuggestion; import android.text.TextUtils; import android.timezone.CountryTimeZones.OffsetResult; import com.android.internal.annotations.VisibleForTesting; import com.android.internal.telephony.NitzData; import com.android.internal.telephony.NitzSignal; import com.android.internal.telephony.NitzStateMachine.DeviceState; import com.android.internal.telephony.nitz.NitzStateMachineImpl.TimeZoneSuggester; import com.android.internal.telephony.nitz.TimeZoneLookupHelper.CountryResult; import com.android.telephony.Rlog; import java.util.Objects; /** * The real implementation of {@link TimeZoneSuggester}. */ @VisibleForTesting public class TimeZoneSuggesterImpl implements TimeZoneSuggester { private static final String LOG_TAG = NitzStateMachineImpl.LOG_TAG; private final DeviceState mDeviceState; private final TimeZoneLookupHelper mTimeZoneLookupHelper; @VisibleForTesting public TimeZoneSuggesterImpl( @NonNull DeviceState deviceState, @NonNull TimeZoneLookupHelper timeZoneLookupHelper) { mDeviceState = Objects.requireNonNull(deviceState); mTimeZoneLookupHelper = Objects.requireNonNull(timeZoneLookupHelper); } @Override @NonNull public TelephonyTimeZoneSuggestion getTimeZoneSuggestion(int slotIndex, @Nullable String countryIsoCode, @Nullable NitzSignal nitzSignal) { try { // Check for overriding NITZ-based signals from Android running in an emulator. TelephonyTimeZoneSuggestion overridingSuggestion = null; if (nitzSignal != null) { NitzData nitzData = nitzSignal.getNitzData(); if (nitzData.getEmulatorHostTimeZone() != null) { TelephonyTimeZoneSuggestion.Builder builder = new TelephonyTimeZoneSuggestion.Builder(slotIndex) .setZoneId(nitzData.getEmulatorHostTimeZone().getID()) .setMatchType(TelephonyTimeZoneSuggestion.MATCH_TYPE_EMULATOR_ZONE_ID) .setQuality(TelephonyTimeZoneSuggestion.QUALITY_SINGLE_ZONE) .addDebugInfo("Emulator time zone override: " + nitzData); overridingSuggestion = builder.build(); } } TelephonyTimeZoneSuggestion suggestion; if (overridingSuggestion != null) { suggestion = overridingSuggestion; } else if (countryIsoCode == null) { if (nitzSignal == null) { suggestion = createEmptySuggestion(slotIndex, "getTimeZoneSuggestion: nitzSignal=null, countryIsoCode=null"); } else { // NITZ only - wait until we have a country. suggestion = createEmptySuggestion(slotIndex, "getTimeZoneSuggestion:" + " nitzSignal=" + nitzSignal + ", countryIsoCode=null"); } } else { // countryIsoCode != null if (nitzSignal == null) { if (countryIsoCode.isEmpty()) { // This is assumed to be a test network with no NITZ data to go on. suggestion = createEmptySuggestion(slotIndex, "getTimeZoneSuggestion: nitzSignal=null, countryIsoCode=\"\""); } else { // Country only suggestion = findTimeZoneFromNetworkCountryCode( slotIndex, countryIsoCode, mDeviceState.currentTimeMillis()); } } else { // nitzSignal != null if (countryIsoCode.isEmpty()) { // We have been told we have a country code but it's empty. This is most // likely because we're on a test network that's using a bogus MCC // (eg, "001"). Obtain a TimeZone based only on the NITZ parameters: without // a country it will be arbitrary, but it should at least have the correct // offset. suggestion = findTimeZoneForTestNetwork(slotIndex, nitzSignal); } else { // We have both NITZ and Country code. suggestion = findTimeZoneFromCountryAndNitz( slotIndex, countryIsoCode, nitzSignal); } } } // Ensure the return value is never null. Objects.requireNonNull(suggestion); return suggestion; } catch (RuntimeException e) { // This would suggest a coding error. Log at a high level and try to avoid leaving the // device in a bad state by making an "empty" suggestion. String message = "getTimeZoneSuggestion: Error during lookup: " + " countryIsoCode=" + countryIsoCode + ", nitzSignal=" + nitzSignal + ", e=" + e.getMessage(); TelephonyTimeZoneSuggestion errorSuggestion = createEmptySuggestion(slotIndex, message); Rlog.w(LOG_TAG, message, e); return errorSuggestion; } } /** * Creates a {@link TelephonyTimeZoneSuggestion} using only NITZ. This happens when the device * is attached to a test cell with an unrecognized MCC. In these cases we try to return a * suggestion for an arbitrary time zone that matches the NITZ offset information. */ @NonNull private TelephonyTimeZoneSuggestion findTimeZoneForTestNetwork( int slotIndex, @NonNull NitzSignal nitzSignal) { Objects.requireNonNull(nitzSignal); NitzData nitzData = Objects.requireNonNull(nitzSignal.getNitzData()); TelephonyTimeZoneSuggestion.Builder suggestionBuilder = new TelephonyTimeZoneSuggestion.Builder(slotIndex); suggestionBuilder.addDebugInfo("findTimeZoneForTestNetwork: nitzSignal=" + nitzSignal); OffsetResult lookupResult = mTimeZoneLookupHelper.lookupByNitz(nitzData); if (lookupResult == null) { suggestionBuilder.addDebugInfo("findTimeZoneForTestNetwork: No zone found"); } else { suggestionBuilder.setZoneId(lookupResult.getTimeZone().getID()); suggestionBuilder.setMatchType( TelephonyTimeZoneSuggestion.MATCH_TYPE_TEST_NETWORK_OFFSET_ONLY); int quality = lookupResult.isOnlyMatch() ? TelephonyTimeZoneSuggestion.QUALITY_SINGLE_ZONE : TelephonyTimeZoneSuggestion.QUALITY_MULTIPLE_ZONES_WITH_SAME_OFFSET; suggestionBuilder.setQuality(quality); suggestionBuilder.addDebugInfo( "findTimeZoneForTestNetwork: lookupResult=" + lookupResult); } return suggestionBuilder.build(); } /** * Creates a {@link TelephonyTimeZoneSuggestion} using network country code and NITZ. */ @NonNull private TelephonyTimeZoneSuggestion findTimeZoneFromCountryAndNitz( int slotIndex, @NonNull String countryIsoCode, @NonNull NitzSignal nitzSignal) { Objects.requireNonNull(countryIsoCode); Objects.requireNonNull(nitzSignal); TelephonyTimeZoneSuggestion.Builder suggestionBuilder = new TelephonyTimeZoneSuggestion.Builder(slotIndex); suggestionBuilder.addDebugInfo("findTimeZoneFromCountryAndNitz:" + " countryIsoCode=" + countryIsoCode + ", nitzSignal=" + nitzSignal); NitzData nitzData = Objects.requireNonNull(nitzSignal.getNitzData()); if (isNitzSignalOffsetInfoBogus(countryIsoCode, nitzData)) { suggestionBuilder.addDebugInfo( "findTimeZoneFromCountryAndNitz: NITZ signal looks bogus"); return suggestionBuilder.build(); } // Try to find a match using both country + NITZ signal. OffsetResult lookupResult = mTimeZoneLookupHelper.lookupByNitzCountry(nitzData, countryIsoCode); if (lookupResult != null) { suggestionBuilder.setZoneId(lookupResult.getTimeZone().getID()); suggestionBuilder.setMatchType( TelephonyTimeZoneSuggestion.MATCH_TYPE_NETWORK_COUNTRY_AND_OFFSET); int quality = lookupResult.isOnlyMatch() ? TelephonyTimeZoneSuggestion.QUALITY_SINGLE_ZONE : TelephonyTimeZoneSuggestion.QUALITY_MULTIPLE_ZONES_WITH_SAME_OFFSET; suggestionBuilder.setQuality(quality); suggestionBuilder.addDebugInfo("findTimeZoneFromCountryAndNitz:" + " lookupResult=" + lookupResult); return suggestionBuilder.build(); } // The country + offset provided no match, so see if the country by itself would be enough. CountryResult countryResult = mTimeZoneLookupHelper.lookupByCountry( countryIsoCode, nitzData.getCurrentTimeInMillis()); if (countryResult == null) { // Country not recognized. suggestionBuilder.addDebugInfo( "findTimeZoneFromCountryAndNitz: lookupByCountry() country not recognized"); return suggestionBuilder.build(); } // If the country has a single zone, or it has multiple zones but the default zone is // "boosted" (i.e. the country default is considered a good suggestion in most cases) then // use it. if (countryResult.quality == CountryResult.QUALITY_SINGLE_ZONE || countryResult.quality == CountryResult.QUALITY_DEFAULT_BOOSTED) { suggestionBuilder.setZoneId(countryResult.zoneId); suggestionBuilder.setMatchType( TelephonyTimeZoneSuggestion.MATCH_TYPE_NETWORK_COUNTRY_ONLY); suggestionBuilder.setQuality(TelephonyTimeZoneSuggestion.QUALITY_SINGLE_ZONE); suggestionBuilder.addDebugInfo( "findTimeZoneFromCountryAndNitz: high quality country-only suggestion:" + " countryResult=" + countryResult); return suggestionBuilder.build(); } // Quality is not high enough to set the zone using country only. suggestionBuilder.addDebugInfo("findTimeZoneFromCountryAndNitz: country-only suggestion" + " quality not high enough. countryResult=" + countryResult); return suggestionBuilder.build(); } /** * Creates a {@link TelephonyTimeZoneSuggestion} using only network country code; works well on * countries which only have one time zone or multiple zones with the same offset. * * @param countryIsoCode country code from network MCC * @param whenMillis the time to use when looking at time zone rules data */ @NonNull private TelephonyTimeZoneSuggestion findTimeZoneFromNetworkCountryCode( int slotIndex, @NonNull String countryIsoCode, long whenMillis) { Objects.requireNonNull(countryIsoCode); if (TextUtils.isEmpty(countryIsoCode)) { throw new IllegalArgumentException("countryIsoCode must not be empty"); } TelephonyTimeZoneSuggestion.Builder suggestionBuilder = new TelephonyTimeZoneSuggestion.Builder(slotIndex); suggestionBuilder.addDebugInfo("findTimeZoneFromNetworkCountryCode:" + " whenMillis=" + whenMillis + ", countryIsoCode=" + countryIsoCode); CountryResult lookupResult = mTimeZoneLookupHelper.lookupByCountry( countryIsoCode, whenMillis); if (lookupResult != null) { suggestionBuilder.setZoneId(lookupResult.zoneId); suggestionBuilder.setMatchType( TelephonyTimeZoneSuggestion.MATCH_TYPE_NETWORK_COUNTRY_ONLY); int quality; if (lookupResult.quality == CountryResult.QUALITY_SINGLE_ZONE || lookupResult.quality == CountryResult.QUALITY_DEFAULT_BOOSTED) { quality = TelephonyTimeZoneSuggestion.QUALITY_SINGLE_ZONE; } else if (lookupResult.quality == CountryResult.QUALITY_MULTIPLE_ZONES_SAME_OFFSET) { quality = TelephonyTimeZoneSuggestion.QUALITY_MULTIPLE_ZONES_WITH_SAME_OFFSET; } else if (lookupResult.quality == CountryResult.QUALITY_MULTIPLE_ZONES_DIFFERENT_OFFSETS) { quality = TelephonyTimeZoneSuggestion.QUALITY_MULTIPLE_ZONES_WITH_DIFFERENT_OFFSETS; } else { // This should never happen. throw new IllegalArgumentException( "lookupResult.quality not recognized: countryIsoCode=" + countryIsoCode + ", whenMillis=" + whenMillis + ", lookupResult=" + lookupResult); } suggestionBuilder.setQuality(quality); suggestionBuilder.addDebugInfo( "findTimeZoneFromNetworkCountryCode: lookupResult=" + lookupResult); } else { suggestionBuilder.addDebugInfo( "findTimeZoneFromNetworkCountryCode: Country not recognized?"); } return suggestionBuilder.build(); } /** * Returns true if the NITZ signal is definitely bogus, assuming that the country is correct. */ private boolean isNitzSignalOffsetInfoBogus(String countryIsoCode, NitzData nitzData) { if (TextUtils.isEmpty(countryIsoCode)) { // We cannot say for sure. return false; } boolean zeroOffsetNitz = nitzData.getLocalOffsetMillis() == 0; return zeroOffsetNitz && !countryUsesUtc(countryIsoCode, nitzData); } private boolean countryUsesUtc(String countryIsoCode, NitzData nitzData) { return mTimeZoneLookupHelper.countryUsesUtc( countryIsoCode, nitzData.getCurrentTimeInMillis()); } }