Merge java_staging/src into java/src.

chrome/android/java_staging/src/org/chromium/chrome/browser/omaha/ExponentialBackoffScheduler.java

Index: chrome/android/java_staging/src/org/chromium/chrome/browser/omaha/ExponentialBackoffScheduler.java
diff --git a/chrome/android/java_staging/src/org/chromium/chrome/browser/omaha/ExponentialBackoffScheduler.java b/chrome/android/java_staging/src/org/chromium/chrome/browser/omaha/ExponentialBackoffScheduler.java
deleted file mode 100644
index d36d8760dbfdd7c361efb02ab05de37a2ebaff9e..0000000000000000000000000000000000000000
--- a/chrome/android/java_staging/src/org/chromium/chrome/browser/omaha/ExponentialBackoffScheduler.java
+++ /dev/null
@@ -1,197 +0,0 @@
-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-package org.chromium.chrome.browser.omaha;
-
-import android.app.AlarmManager;
-import android.app.PendingIntent;
-import android.content.Context;
-import android.content.Intent;
-import android.content.SharedPreferences;
-import android.util.Log;
-
-import org.chromium.base.VisibleForTesting;
-
-import java.util.Date;
-import java.util.Random;
-
-import javax.annotation.concurrent.NotThreadSafe;
-
-/**
- * Manages a timer that implements exponential backoff for failed attempts.
- *
- * The first timer will fire after BASE_MILLISECONDS.  On a failure, the timer is changed to
- * (randomInteger[0, 2^failures) + 1) * BASE_MILLISECONDS.  MAX_MILLISECONDS is used to ensure that
- * you aren't waiting years for a timer to fire.
- *
- * The state is stored in shared preferences to ensure that they are kept after the device sleeps.
- * Because multiple ExponentialBackoffSchedulers can be used by different components,
- * the owning class must set the preference name.
- *
- * Timestamps are recorded in RTC to avoid situations where the phone is rebooted, messing up
- * any timestamps generated using elapsedRealtime().
- *
- * This class is not thread-safe because any two different classes could be accessing the same
- * SharedPreferences.
- *
- * TODO(dfalcantara): Consider making this an AlarmManagerHelper class to manage general alarms.
- */
-@NotThreadSafe
-public class ExponentialBackoffScheduler {
-    private static final String TAG = "ExponentialBackoffScheduler";
-
-    private static final String PREFERENCE_DELAY = "delay";
-    private static final String PREFERENCE_FAILED_ATTEMPTS = "backoffFailedAttempts";
-
-    private static Random sRandom = new Random();
-
-    private static final int MAX_EXPONENT = 10;
-
-    private final long mBaseMilliseconds;
-    private final long mMaxMilliseconds;
-    private final Context mContext;
-    private final String mPreferencePackage;
-
-    /**
-     * Creates a new scheduler.
-     * @param packageName The name under which to store its state in SharedPreferences.
-     * @param context The application's context.
-     * @param baseMilliseconds Used to calculate random backoff times.
-     * @param maxMilliseconds The absolute maximum delay allowed.
-     */
-    public ExponentialBackoffScheduler(String packageName, Context context, long baseMilliseconds,
-            long maxMilliseconds) {
-        mPreferencePackage = packageName;
-        mContext = context;
-        mBaseMilliseconds = baseMilliseconds;
-        mMaxMilliseconds = maxMilliseconds;
-    }
-
-    /**
-     * Creates an alarm to fire the specified intent after a random delay.
-     * @param intent The intent to fire.
-     * @return the timestamp of the scheduled intent
-     */
-    public long createAlarm(Intent intent) {
-        long delay = generateRandomDelay();
-        long timestamp = delay + getCurrentTime();
-        return createAlarm(intent, timestamp);
-    }
-
-    /**
-     * Creates an alarm to fire the specified intent at the specified time.
-     * @param intent The intent to fire.
-     * @return the timestamp of the scheduled intent
-     */
-    public long createAlarm(Intent intent, long timestamp) {
-        PendingIntent retryPIntent = PendingIntent.getService(mContext, 0, intent, 0);
-        AlarmManager am = (AlarmManager) mContext.getSystemService(Context.ALARM_SERVICE);
-        setAlarm(am, timestamp, retryPIntent);
-        return timestamp;
-    }
-
-    /**
-     * Attempts to cancel any alarms set using the given Intent.
-     * @param scheduledIntent Intent that may have been previously scheduled.
-     * @return whether or not an alarm was canceled.
-     */
-    public boolean cancelAlarm(Intent scheduledIntent) {
-        PendingIntent pendingIntent = PendingIntent.getService(mContext, 0, scheduledIntent,
-                PendingIntent.FLAG_NO_CREATE);
-        if (pendingIntent != null) {
-            AlarmManager am = (AlarmManager) mContext.getSystemService(Context.ALARM_SERVICE);
-            am.cancel(pendingIntent);
-            pendingIntent.cancel();
-            return true;
-        } else {
-            return false;
-        }
-    }
-
-    public int getNumFailedAttempts() {
-        SharedPreferences preferences = getSharedPreferences();
-        return preferences.getInt(PREFERENCE_FAILED_ATTEMPTS, 0);
-    }
-
-    public void increaseFailedAttempts() {
-        SharedPreferences preferences = getSharedPreferences();
-        int numFailedAttempts = getNumFailedAttempts() + 1;
-        preferences.edit()
-            .putInt(PREFERENCE_FAILED_ATTEMPTS, numFailedAttempts)
-            .apply();
-    }
-
-    public void resetFailedAttempts() {
-        SharedPreferences preferences = getSharedPreferences();
-        preferences.edit()
-            .putInt(PREFERENCE_FAILED_ATTEMPTS, 0)
-            .apply();
-    }
-
-    /**
-     * Returns a timestamp representing now, according to the backoff scheduler.
-     */
-    public long getCurrentTime() {
-        return System.currentTimeMillis();
-    }
-
-    /**
-     * Returns the delay used to generate the last alarm.  If no previous alarm was generated,
-     * return the base delay.
-     */
-    public long getGeneratedDelay() {
-        SharedPreferences preferences = getSharedPreferences();
-        return preferences.getLong(PREFERENCE_DELAY, mBaseMilliseconds);
-    }
-
-    /**
-     * Sets an alarm in the alarm manager.
-     */
-    @VisibleForTesting
-    protected void setAlarm(AlarmManager am, long timestamp, PendingIntent retryPIntent) {
-        Log.v(TAG, "now(" + new Date(getCurrentTime()) + ") refiringAt("
-                + new Date(timestamp) + ")");
-        am.set(AlarmManager.RTC, timestamp, retryPIntent);
-    }
-
-    /**
-     * Determines the amount of time to wait for the current delay, then saves it.
-     * @return the number of milliseconds to wait.
-     */
-    private long generateRandomDelay() {
-        long delay;
-        int numFailedAttempts = getNumFailedAttempts();
-        if (numFailedAttempts == 0) {
-            delay = Math.min(mBaseMilliseconds, mMaxMilliseconds);
-        } else {
-            int backoffCoefficient = computeConstrainedBackoffCoefficient(numFailedAttempts);
-            delay = Math.min(backoffCoefficient * mBaseMilliseconds, mMaxMilliseconds);
-        }
-
-        // Save the delay for sanity checks.
-        SharedPreferences preferences = getSharedPreferences();
-        preferences.edit()
-            .putLong(PREFERENCE_DELAY, delay)
-            .apply();
-        return delay;
-    }
-
-    /**
-     * Calculates a random coefficient based on the number of cumulative failed attempts.
-     * @param numFailedAttempts Number of cumulative failed attempts
-     * @return A random number between 1 and 2^N, where N is the smallest value of MAX_EXPONENT and
-     *         numFailedAttempts
-     */
-    private int computeConstrainedBackoffCoefficient(int numFailedAttempts) {
-        int n = Math.min(MAX_EXPONENT, numFailedAttempts);
-        int twoToThePowerOfN = 1 << n;
-        return sRandom.nextInt(twoToThePowerOfN) + 1;
-    }
-
-    private SharedPreferences getSharedPreferences() {
-        SharedPreferences preferences =
-                mContext.getSharedPreferences(mPreferencePackage, Context.MODE_PRIVATE);
-        return preferences;
-    }
-}