| /* |
| * 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.wifi.util; |
| |
| import com.android.server.wifi.Clock; |
| |
| /** |
| * Manages a quota that is reset at the beginning of each new time period. |
| */ |
| public class TimedQuotaManager { |
| private final Clock mClock; |
| |
| private final long mQuota; |
| private final long mPeriodMillis; |
| private final long mStartTimeMillis; |
| |
| /** |
| * The number of elapsed periods between {@link #mStartTimeMillis} and the time of the last call |
| * to {@link #requestQuota()}. |
| */ |
| private long mLastPeriod; |
| /** How much quota has been consumed in the current period. */ |
| private long mConsumedQuota; |
| |
| /** |
| * Constructor. |
| * @param clock Clock instance. |
| * @param quota the maximum quota for a given period. |
| * @param periodMillis the quota will be reset at the beginning of each new period. |
| */ |
| public TimedQuotaManager(Clock clock, long quota, long periodMillis) { |
| mClock = clock; |
| mQuota = quota; |
| mPeriodMillis = periodMillis; |
| mStartTimeMillis = clock.getElapsedSinceBootMillis(); |
| mLastPeriod = 0; |
| mConsumedQuota = 0; |
| } |
| |
| /** |
| * Requests one quota. If there is sufficient remaining quota for the current period, |
| * returns true and consumes one quota. Otherwise, returns false. |
| */ |
| public boolean requestQuota() { |
| long currentPeriod = getCurrentPeriod(); |
| if (mLastPeriod < currentPeriod) { |
| mLastPeriod = currentPeriod; |
| mConsumedQuota = 0; |
| } |
| if (mConsumedQuota < mQuota) { |
| mConsumedQuota++; |
| return true; |
| } |
| return false; |
| } |
| |
| private long getCurrentPeriod() { |
| return (mClock.getElapsedSinceBootMillis() - mStartTimeMillis) / mPeriodMillis; |
| } |
| |
| @Override |
| public String toString() { |
| return "TimedQuotaManager{" |
| + "mQuota=" + mQuota |
| + ", mPeriodMillis=" + mPeriodMillis |
| + ", mStartTimeMillis=" + mStartTimeMillis |
| + ", mLastPeriod=" + mLastPeriod |
| + ", mConsumedQuota=" + mConsumedQuota |
| + '}'; |
| } |
| } |