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/*
* Copyright (C) 2022 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.geotz.app;
import android.content.Context;
import androidx.annotation.NonNull;
import com.android.timezone.location.provider.GeoDataFileManager;
import com.google.common.hash.Hashing;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;
import java.util.Objects;
import java.util.Properties;
/**
* An implementation of {@link GeoDataFileManager} that copies the tzs2.dat classpath resource to
* an app file path for reading.
*/
public final class GeoDataFileManagerImpl implements GeoDataFileManager {
/**
* The config properties key to get the resource path of the tzs2.dat file to use for time zone
* boundaries.
*/
private static final String RESOURCE_CONFIG_KEY_GEODATA_RESOURCE = "geodata.resource";
/**
* The config properties key to get the location of the tzs2.dat file to use for time zone
* boundaries.
*/
private static final String RESOURCE_CONFIG_KEY_GEODATA_SHA256= "geodata.sha256";
private File mGeoDataFile;
@Override
public void init(@NonNull Context context, @NonNull Properties configProperties)
throws IOException {
File geoDataFile = new File(context.getFilesDir(), "tzs2.dat");
ClassLoader classLoader = getClass().getClassLoader();
String geoDataResource = configProperties.getProperty(RESOURCE_CONFIG_KEY_GEODATA_RESOURCE);
String expectedSha256 = configProperties.getProperty(RESOURCE_CONFIG_KEY_GEODATA_SHA256);
if (!geoDataFile.exists() || !Objects.equals(computeSha256(geoDataFile), expectedSha256)) {
// Copy the resource to the app persistent files dir.
copyResource(classLoader, geoDataResource, geoDataFile, expectedSha256);
}
mGeoDataFile = geoDataFile;
}
@Override
@NonNull
public File getGeoDataFile() {
return Objects.requireNonNull(mGeoDataFile);
}
private static void copyResource(@NonNull ClassLoader classLoader, @NonNull String resourceName,
@NonNull File targetPath, @NonNull String expectedSha256) {
boolean success = false;
try (InputStream resourceStream = classLoader.getResourceAsStream(resourceName)) {
if (resourceStream == null) {
throw new IllegalStateException("Unable to find "
+ " resource=" + resourceName);
}
Files.copy(resourceStream, targetPath.toPath(), StandardCopyOption.REPLACE_EXISTING);
String actualSha256 = computeSha256(targetPath);
if (!actualSha256.equals(expectedSha256)) {
throw new IllegalStateException(
"SHA256 expected=" + expectedSha256 + ", actual=" + actualSha256);
}
success = true;
} catch (IOException e) {
throw new IllegalStateException("Unable to copy resource from"
+ " resource=" + resourceName
+ " to targetPath=" + targetPath, e);
} finally {
if (!success) {
targetPath.delete();
}
}
}
private static String computeSha256(File file) {
try {
return com.google.common.io.Files.asByteSource(file).hash(Hashing.sha256()).toString();
} catch (IOException e) {
throw new IllegalStateException("Unable to compute hash for file=" + file);
}
}
}
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