Introducing UptcMap.

/*

 * 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.server.utils.quota;

import android.annotation.NonNull;

import android.annotation.Nullable;

import android.util.ArrayMap;

import android.util.SparseArrayMap;

import java.util.function.Consumer;

/**

 * A SparseArrayMap of ArrayMaps, which is suitable for holding userId-packageName-tag combination

 * (UPTC)->object associations. Tags are any desired String.

 *

 * @see Uptc

 */

class UptcMap<T> {

    private final SparseArrayMap<ArrayMap<String, T>> mData = new SparseArrayMap<>();

    public void add(int userId, @NonNull String packageName, @Nullable String tag,

            @Nullable T obj) {

        ArrayMap<String, T> data = mData.get(userId, packageName);

        if (data == null) {

            data = new ArrayMap<>();

            mData.add(userId, packageName, data);

        }

        data.put(tag, obj);

    }

    public void clear() {

        mData.clear();

    }

    public boolean contains(int userId, @NonNull String packageName) {

        return mData.contains(userId, packageName);

    }

    public boolean contains(int userId, @NonNull String packageName, @Nullable String tag) {

        // This structure never inserts a null ArrayMap, so if get(userId, packageName) returns

        // null, the UPTC was never inserted.

        ArrayMap<String, T> data = mData.get(userId, packageName);

        return data != null && data.containsKey(tag);

    }

    /** Removes all the data for the user, if there was any. */

    public void delete(int userId) {

        mData.delete(userId);

    }

    /** Removes the data for the user, package, and tag, if there was any. */

    public void delete(int userId, @NonNull String packageName, @Nullable String tag) {

        final ArrayMap<String, T> data = mData.get(userId, packageName);

        if (data != null) {

            data.remove(tag);

            if (data.size() == 0) {

                mData.delete(userId, packageName);

            }

        }

    }

    /** Removes the data for the user and package, if there was any. */

    public ArrayMap<String, T> delete(int userId, @NonNull String packageName) {

        return mData.delete(userId, packageName);

    }

    /**

     * Returns the set of tag -> object mappings for the given userId and packageName

     * combination.

     */

    @Nullable

    public ArrayMap<String, T> get(int userId, @NonNull String packageName) {

        return mData.get(userId, packageName);

    }

    /** Returns the saved object for the given UPTC. */

    @Nullable

    public T get(int userId, @NonNull String packageName, @Nullable String tag) {

        final ArrayMap<String, T> data = mData.get(userId, packageName);

        return data != null ? data.get(tag) : null;

    }

    /**

     * Returns the index for which {@link #getUserIdAtIndex(int)} would return the specified userId,

     * or a negative number if the specified userId is not mapped.

     */

    public int indexOfUserId(int userId) {

        return mData.indexOfKey(userId);

    }

    /**

     * Returns the index for which {@link #getPackageNameAtIndex(int, int)} would return the

     * specified userId, or a negative number if the specified userId and packageName are not mapped

     * together.

     */

    public int indexOfUserIdAndPackage(int userId, @NonNull String packageName) {

        return mData.indexOfKey(userId, packageName);

    }

    /** Returns the userId at the given index. */

    public int getUserIdAtIndex(int index) {

        return mData.keyAt(index);

    }

    /** Returns the package name at the given index. */

    @NonNull

    public String getPackageNameAtIndex(int userIndex, int packageIndex) {

        return mData.keyAt(userIndex, packageIndex);

    }

    /** Returns the tag at the given index. */

    @NonNull

    public String getTagAtIndex(int userIndex, int packageIndex, int tagIndex) {

        // This structure never inserts a null ArrayMap, so if the indices are valid, valueAt()

        // won't return null.

        return mData.valueAt(userIndex, packageIndex).keyAt(tagIndex);

    }

    /** Returns the size of the outer (userId) array. */

    public int userCount() {

        return mData.numMaps();

    }

    /** Returns the number of packages saved for a given userId. */

    public int packageCountForUser(int userId) {

        return mData.numElementsForKey(userId);

    }

    /** Returns the number of tags saved for a given userId-packageName combination. */

    public int tagCountForUserAndPackage(int userId, @NonNull String packageName) {

        final ArrayMap data = mData.get(userId, packageName);

        return data != null ? data.size() : 0;

    }

    /** Returns the value T at the given user, package, and tag indices. */

    @Nullable

    public T valueAt(int userIndex, int packageIndex, int tagIndex) {

        final ArrayMap<String, T> data = mData.valueAt(userIndex, packageIndex);

        return data != null ? data.valueAt(tagIndex) : null;

    }

    public void forEach(Consumer<T> consumer) {

        mData.forEach((tagMap) -> {

            for (int i = tagMap.size() - 1; i >= 0; --i) {

                consumer.accept(tagMap.valueAt(i));

            }

        });

    }

}