service/src/com/android/car/telemetry/publisher/statsconverters/GaugeMetricDataConverter.java

/*
 * Copyright (C) 2021 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.car.telemetry.publisher.statsconverters;

import android.os.PersistableBundle;

import com.android.car.telemetry.AtomsProto;
import com.android.car.telemetry.StatsLogProto.DimensionsValue;
import com.android.car.telemetry.StatsLogProto.GaugeBucketInfo;
import com.android.car.telemetry.StatsLogProto.GaugeMetricData;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * Class for converting gauge metric data to {@link PersistableBundle} compatible format.
 */
public class GaugeMetricDataConverter {
    static final String ELAPSED_TIME_NANOS = "elapsed_timestamp_nanos";

    /**
     * Converts a list of {@link StatsLogProto.GaugeMetricData} to {@link PersistableBundle}
     * format such that along with the elapsed time array each field of the atom has an associated
     * array containing the field's data in order received, matching the elapsed time array order.
     * The atoms are extracted out of the each bucket while preserving the order they had in the
     * bucket.
     *
     * Example:
     * {
     *   elapsed_timestamp_nanos: [32948395739, 45623453646, ...]
     *   uid: [1000, 1100, ...]
     *   ...
     * }
     *
     * @param gaugeDataList the list of {@link StatsLogProto.GaugeMetricData} to be converted.
     * @param dimensionsFieldsIds field ids for fields that are encoded in {@link DimensionsValue}.
     * @param hashToStringMap hash to string mapping for decoding the some dimension values.
     * @return {@link PersistableBundle} that holds the converted values.
     * @throws StatsConversionException if atom field mismatch or can't convert dimension value.
     */
    static PersistableBundle convertGaugeDataList(
            List<GaugeMetricData> gaugeDataList,
            List<Integer> dimensionsFieldsIds,
            Map<Long, String> hashToStringMap) throws StatsConversionException {
        List<Long> elapsedTimes = new ArrayList<>();
        List<AtomsProto.Atom> atoms = new ArrayList<>();
        // This list contains dimensionsValues for each atom, matching in index and list size.
        List<List<DimensionsValue>> dimensionsValuesList = new ArrayList<>();
        for (GaugeMetricData gaugeData : gaugeDataList) {
            // The dimensionsValue is same for all stoms in the same GaugeMetricData.
            List<DimensionsValue> dimensionsValues = gaugeData.getDimensionLeafValuesInWhatList();
            for (GaugeBucketInfo bi : gaugeData.getBucketInfoList()) {
                elapsedTimes.addAll(bi.getElapsedTimestampNanosList());
                for (AtomsProto.Atom atom : bi.getAtomList()) {
                    atoms.add(atom);
                    dimensionsValuesList.add(dimensionsValues);
                }
            }
        }
        PersistableBundle bundle = AtomListConverter.convert(
                atoms,
                dimensionsFieldsIds,
                dimensionsValuesList,
                hashToStringMap);
        long[] elapsedTimesArray = new long[elapsedTimes.size()];
        for (int i = 0; i < elapsedTimes.size(); ++i) {
            elapsedTimesArray[i] = elapsedTimes.get(i);
        }
        bundle.putLongArray(ELAPSED_TIME_NANOS, elapsedTimesArray);
        return bundle;
    }
}