Adding Uptc data object.

/*

 * 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.proto.ProtoOutputStream;

import android.util.quota.UptcProto;

import java.util.Objects;

/**

 * A data object that represents a userId-packageName-tag combination (UPTC). The tag can be any

 * desired String.

 */

final class Uptc {

    public final int userId;

    @NonNull

    public final String packageName;

    @Nullable

    public final String tag;

    private final int mHash;

    /** Construct a new Uptc with the specified values. */

    Uptc(int userId, @NonNull String packageName, @Nullable String tag) {

        this.userId = userId;

        this.packageName = packageName;

        this.tag = tag;

        mHash = 31 * userId

                + 31 * packageName.hashCode()

                + tag == null ? 0 : (31 * tag.hashCode());

    }

    @Override

    public String toString() {

        return string(userId, packageName, tag);

    }

    void dumpDebug(ProtoOutputStream proto, long fieldId) {

        final long token = proto.start(fieldId);

        proto.write(UptcProto.USER_ID, userId);

        proto.write(UptcProto.NAME, packageName);

        proto.write(UptcProto.TAG, tag);

        proto.end(token);

    }

    @Override

    public boolean equals(Object obj) {

        if (this == obj) {

            return true;

        }

        if (obj instanceof Uptc) {

            final Uptc other = (Uptc) obj;

            return userId == other.userId

                    && Objects.equals(packageName, other.packageName)

                    && Objects.equals(tag, other.tag);

        }

        return false;

    }

    @Override

    public int hashCode() {

        return mHash;

    }

    /** Standardize the output of a UPTC. */

    static String string(int userId, @NonNull String packageName, @Nullable String tag) {

        return "<" + userId + ">" + packageName + (tag == null ? "" : ("::" + tag));

    }

}