PermissionController/src/com/android/packageinstaller/role/model/ExclusiveDefaultHolderMixin.java

/*
 * 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 com.android.packageinstaller.role.model;

import android.content.Context;
import android.content.pm.ApplicationInfo;
import android.content.res.Resources;
import android.text.TextUtils;
import android.util.Log;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import com.android.packageinstaller.permission.utils.CollectionUtils;
import com.android.packageinstaller.role.utils.PackageUtils;

import java.util.List;

/**
 * Mixin for {@link RoleBehavior#getDefaultHolders(Role, Context)} that returns a single default
 * role holder from the corresponding string resource.
 */
public class ExclusiveDefaultHolderMixin {

    private static final String LOG_TAG = ExclusiveDefaultHolderMixin.class.getSimpleName();

    private ExclusiveDefaultHolderMixin() {}

    /**
     * @see Role#getDefaultHolders(Context)
     */
    @NonNull
    public static List<String> getDefaultHolders(@NonNull Role role, @NonNull String resourceName,
            @NonNull Context context) {
        return CollectionUtils.singletonOrEmpty(getDefaultHolder(role, resourceName, context));
    }

    /**
     * @see Role#getDefaultHolders(Context)
     */
    @Nullable
    public static String getDefaultHolder(@NonNull Role role, @NonNull String resourceName,
            @NonNull Context context) {
        Resources resources = context.getResources();
        int resourceId = resources.getIdentifier(resourceName, "string", "android");
        if (resourceId == 0) {
            Log.w(LOG_TAG, "Cannot find resource for default holder: " + resourceName);
            return null;
        }
        String packageName;
        try {
            packageName = resources.getString(resourceId);
        } catch (Resources.NotFoundException e) {
            Log.w(LOG_TAG, "Cannot get resource for default holder: " + resourceName, e);
            return null;
        }
        if (TextUtils.isEmpty(packageName)) {
            return null;
        }

        ApplicationInfo applicationInfo = PackageUtils.getApplicationInfo(packageName, context);
        if (applicationInfo == null) {
            Log.w(LOG_TAG, "Cannot get ApplicationInfo for default holder, config: " + resourceName
                    + ", package: " + packageName);
            return null;
        }
        if ((applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) == 0) {
            Log.w(LOG_TAG, "Default holder is not a system app, config: " + resourceName
                    + ", package: " + packageName);
            return null;
        }

        if (!role.isPackageQualified(packageName, context)) {
            Log.w(LOG_TAG, "Default holder does not qualify for the role, config: " + resourceName
                    + ", package: " + packageName);
            return null;
        }
        return packageName;
    }
}