1 files changed, 200 insertions, 0 deletions
diff --git a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoBatteryManager.java b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoBatteryManager.java
new file mode 100644
index 0000000000..19f489b399
--- /dev/null
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoBatteryManager.java
@@ -0,0 +1,200 @@
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.os.BatteryManager;
+import android.os.Build;
+import android.os.SystemClock;
+import android.util.Log;
+import org.mozilla.gecko.annotation.WrapForJNI;
+
+public class GeckoBatteryManager extends BroadcastReceiver {
+  private static final String LOGTAG = "GeckoBatteryManager";
+
+  // Those constants should be keep in sync with the ones in:
+  // dom/battery/Constants.h
+  private static final double kDefaultLevel = 1.0;
+  private static final boolean kDefaultCharging = true;
+  private static final double kDefaultRemainingTime = 0.0;
+  private static final double kUnknownRemainingTime = -1.0;
+
+  private static long sLastLevelChange;
+  private static boolean sNotificationsEnabled;
+  private static double sLevel = kDefaultLevel;
+  private static boolean sCharging = kDefaultCharging;
+  private static double sRemainingTime = kDefaultRemainingTime;
+
+  private static final GeckoBatteryManager sInstance = new GeckoBatteryManager();
+
+  private final IntentFilter mFilter;
+  private Context mApplicationContext;
+  private boolean mIsEnabled;
+
+  public static GeckoBatteryManager getInstance() {
+    return sInstance;
+  }
+
+  private GeckoBatteryManager() {
+    mFilter = new IntentFilter();
+    mFilter.addAction(Intent.ACTION_BATTERY_CHANGED);
+  }
+
+  public synchronized void start(final Context context) {
+    if (mIsEnabled) {
+      Log.w(LOGTAG, "Already started!");
+      return;
+    }
+
+    mApplicationContext = context.getApplicationContext();
+    // registerReceiver will return null if registering fails.
+    if (mApplicationContext.registerReceiver(this, mFilter) == null) {
+      Log.e(LOGTAG, "Registering receiver failed");
+    } else {
+      mIsEnabled = true;
+    }
+  }
+
+  public synchronized void stop() {
+    if (!mIsEnabled) {
+      Log.w(LOGTAG, "Already stopped!");
+      return;
+    }
+
+    mApplicationContext.unregisterReceiver(this);
+    mApplicationContext = null;
+    mIsEnabled = false;
+  }
+
+  @WrapForJNI(calledFrom = "ui", dispatchTo = "gecko")
+  private static native void onBatteryChange(double level, boolean charging, double remainingTime);
+
+  @Override
+  public void onReceive(final Context context, final Intent intent) {
+    if (!intent.getAction().equals(Intent.ACTION_BATTERY_CHANGED)) {
+      Log.e(LOGTAG, "Got an unexpected intent!");
+      return;
+    }
+
+    final boolean previousCharging = isCharging();
+    final double previousLevel = getLevel();
+
+    // NOTE: it might not be common (in 2012) but technically, Android can run
+    // on a device that has no battery so we want to make sure it's not the case
+    // before bothering checking for battery state.
+    // However, the Galaxy Nexus phone advertises itself as battery-less which
+    // force us to special-case the logic.
+    // See the Google bug: https://code.google.com/p/android/issues/detail?id=22035
+    if (intent.getBooleanExtra(BatteryManager.EXTRA_PRESENT, false)
+        || Build.MODEL.equals("Galaxy Nexus")) {
+      final int plugged = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1);
+      if (plugged == -1) {
+        sCharging = kDefaultCharging;
+        Log.e(LOGTAG, "Failed to get the plugged status!");
+      } else {
+        // Likely, if plugged > 0, it's likely plugged and charging but the doc
+        // isn't clear about that.
+        sCharging = plugged != 0;
+      }
+
+      if (sCharging != previousCharging) {
+        sRemainingTime = kUnknownRemainingTime;
+        // The new remaining time is going to take some time to show up but
+        // it's the best way to show a not too wrong value.
+        sLastLevelChange = 0;
+      }
+
+      // We need two doubles because sLevel is a double.
+      final double current = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);
+      final double max = intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1);
+      if (current == -1 || max == -1) {
+        Log.e(LOGTAG, "Failed to get battery level!");
+        sLevel = kDefaultLevel;
+      } else {
+        sLevel = current / max;
+      }
+
+      if (sLevel == 1.0 && sCharging) {
+        sRemainingTime = kDefaultRemainingTime;
+      } else if (sLevel != previousLevel) {
+        // Estimate remaining time.
+        if (sLastLevelChange != 0) {
+          // Use elapsedRealtime() because we want to track time across device sleeps.
+          final long currentTime = SystemClock.elapsedRealtime();
+          final long dt = (currentTime - sLastLevelChange) / 1000;
+          final double dLevel = sLevel - previousLevel;
+
+          if (sCharging) {
+            if (dLevel < 0) {
+              sRemainingTime = kUnknownRemainingTime;
+            } else {
+              sRemainingTime = Math.round(dt / dLevel * (1.0 - sLevel));
+            }
+          } else {
+            if (dLevel > 0) {
+              Log.w(LOGTAG, "When discharging, level should decrease!");
+              sRemainingTime = kUnknownRemainingTime;
+            } else {
+              sRemainingTime = Math.round(dt / -dLevel * sLevel);
+            }
+          }
+
+          sLastLevelChange = currentTime;
+        } else {
+          // That's the first time we got an update, we can't do anything.
+          sLastLevelChange = SystemClock.elapsedRealtime();
+        }
+      }
+    } else {
+      sLevel = kDefaultLevel;
+      sCharging = kDefaultCharging;
+      sRemainingTime = kDefaultRemainingTime;
+    }
+
+    /*
+     * We want to inform listeners if the following conditions are fulfilled:
+     *  - we have at least one observer;
+     *  - the charging state or the level has changed.
+     *
+     * Note: no need to check for a remaining time change given that it's only
+     * updated if there is a level change or a charging change.
+     *
+     * The idea is to prevent doing all the way to the DOM code in the child
+     * process to finally not send an event.
+     */
+    if (sNotificationsEnabled
+        && (previousCharging != isCharging() || previousLevel != getLevel())) {
+      onBatteryChange(getLevel(), isCharging(), getRemainingTime());
+    }
+  }
+
+  public static boolean isCharging() {
+    return sCharging;
+  }
+
+  public static double getLevel() {
+    return sLevel;
+  }
+
+  public static double getRemainingTime() {
+    return sRemainingTime;
+  }
+
+  public static void enableNotifications() {
+    sNotificationsEnabled = true;
+  }
+
+  public static void disableNotifications() {
+    sNotificationsEnabled = false;
+  }
+
+  public static double[] getCurrentInformation() {
+    return new double[] {getLevel(), isCharging() ? 1.0 : 0.0, getRemainingTime()};
+  }
+}