/*
* Copyright (C) 2012 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.location;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import android.app.AppOpsManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.location.Geofence;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.location.LocationRequest;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.os.PowerManager;
import android.os.SystemClock;
import android.util.Slog;
import com.android.server.LocationManagerService;
public class GeofenceManager implements LocationListener, PendingIntent.OnFinished {
private static final String TAG = "GeofenceManager";
private static final boolean D = LocationManagerService.D;
private static final int MSG_UPDATE_FENCES = 1;
/**
* Assume a maximum land speed, as a heuristic to throttle location updates.
* (Air travel should result in an airplane mode toggle which will
* force a new location update anyway).
*/
private static final int MAX_SPEED_M_S = 100; // 360 km/hr (high speed train)
/**
* Maximum age after which a location is no longer considered fresh enough to use.
*/
private static final long MAX_AGE_NANOS = 5 * 60 * 1000000000L; // five minutes
/**
* Most frequent update interval allowed.
*/
private static final long MIN_INTERVAL_MS = 1 * 60 * 1000; // one minute
/**
* Least frequent update interval allowed.
*/
private static final long MAX_INTERVAL_MS = 2 * 60 * 60 * 1000; // two hours
private final Context mContext;
private final LocationManager mLocationManager;
private final AppOpsManager mAppOps;
private final PowerManager.WakeLock mWakeLock;
private final GeofenceHandler mHandler;
private final LocationBlacklist mBlacklist;
private Object mLock = new Object();
// access to members below is synchronized on mLock
/**
* A list containing all registered geofences.
*/
private List<GeofenceState> mFences = new LinkedList<GeofenceState>();
/**
* This is set true when we have an active request for {@link Location} updates via
* {@link LocationManager#requestLocationUpdates(LocationRequest, LocationListener,
* android.os.Looper).
*/
private boolean mReceivingLocationUpdates;
/**
* The update interval component of the current active {@link Location} update request.
*/
private long mLocationUpdateInterval;
/**
* The {@link Location} most recently received via {@link #onLocationChanged(Location)}.
*/
private Location mLastLocationUpdate;
/**
* This is set true when a {@link Location} is received via
* {@link #onLocationChanged(Location)} or {@link #scheduleUpdateFencesLocked()}, and cleared
* when that Location has been processed via {@link #updateFences()}
*/
private boolean mPendingUpdate;
public GeofenceManager(Context context, LocationBlacklist blacklist) {
mContext = context;
mLocationManager = (LocationManager) mContext.getSystemService(Context.LOCATION_SERVICE);
mAppOps = (AppOpsManager)mContext.getSystemService(Context.APP_OPS_SERVICE);
PowerManager powerManager = (PowerManager) mContext.getSystemService(Context.POWER_SERVICE);
mWakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, TAG);
mHandler = new GeofenceHandler();
mBlacklist = blacklist;
}
public void addFence(LocationRequest request, Geofence geofence, PendingIntent intent,
int allowedResolutionLevel, int uid, String packageName) {
if (D) {
Slog.d(TAG, "addFence: request=" + request + ", geofence=" + geofence
+ ", intent=" + intent + ", uid=" + uid + ", packageName=" + packageName);
}
GeofenceState state = new GeofenceState(geofence,
request.getExpireAt(), allowedResolutionLevel, uid, packageName, intent);
synchronized (mLock) {
// first make sure it doesn't already exist
for (int i = mFences.size() - 1; i >= 0; i--) {
GeofenceState w = mFences.get(i);
if (geofence.equals(w.mFence) && intent.equals(w.mIntent)) {
// already exists, remove the old one
mFences.remove(i);
break;
}
}
mFences.add(state);
scheduleUpdateFencesLocked();
}
}
public void removeFence(Geofence fence, PendingIntent intent) {
if (D) {
Slog.d(TAG, "removeFence: fence=" + fence + ", intent=" + intent);
}
synchronized (mLock) {
Iterator<GeofenceState> iter = mFences.iterator();
while (iter.hasNext()) {
GeofenceState state = iter.next();
if (state.mIntent.equals(intent)) {
if (fence == null) {
// always remove
iter.remove();
} else {
// just remove matching fences
if (fence.equals(state.mFence)) {
iter.remove();
}
}
}
}
scheduleUpdateFencesLocked();
}
}
public void removeFence(String packageName) {
if (D) {
Slog.d(TAG, "removeFence: packageName=" + packageName);
}
synchronized (mLock) {
Iterator<GeofenceState> iter = mFences.iterator();
while (iter.hasNext()) {
GeofenceState state = iter.next();
if (state.mPackageName.equals(packageName)) {
iter.remove();
}
}
scheduleUpdateFencesLocked();
}
}
private void removeExpiredFencesLocked() {
long time = SystemClock.elapsedRealtime();
Iterator<GeofenceState> iter = mFences.iterator();
while (iter.hasNext()) {
GeofenceState state = iter.next();
if (state.mExpireAt < time) {
iter.remove();
}
}
}
private void scheduleUpdateFencesLocked() {
if (!mPendingUpdate) {
mPendingUpdate = true;
mHandler.sendEmptyMessage(MSG_UPDATE_FENCES);
}
}
/**
* Returns the location received most recently from {@link #onLocationChanged(Location)},
* or consult {@link LocationManager#getLastLocation()} if none has arrived. Does not return
* either if the location would be too stale to be useful.
*
* @return a fresh, valid Location, or null if none is available
*/
private Location getFreshLocationLocked() {
// Prefer mLastLocationUpdate to LocationManager.getLastLocation().
Location location = mReceivingLocationUpdates ? mLastLocationUpdate : null;
if (location == null && !mFences.isEmpty()) {
location = mLocationManager.getLastLocation();
}
// Early out for null location.
if (location == null) {
return null;
}
// Early out for stale location.
long now = SystemClock.elapsedRealtimeNanos();
if (now - location.getElapsedRealtimeNanos() > MAX_AGE_NANOS) {
return null;
}
// Made it this far? Return our fresh, valid location.
return location;
}
/**
* The geofence update loop. This function removes expired fences, then tests the most
* recently-received {@link Location} against each registered {@link GeofenceState}, sending
* {@link Intent}s for geofences that have been tripped. It also adjusts the active location
* update request with {@link LocationManager} as appropriate for any active geofences.
*/
// Runs on the handler.
private void updateFences() {
List<PendingIntent> enterIntents = new LinkedList<PendingIntent>();
List<PendingIntent> exitIntents = new LinkedList<PendingIntent>();
synchronized (mLock) {
mPendingUpdate = false;
// Remove expired fences.
removeExpiredFencesLocked();
// Get a location to work with, either received via onLocationChanged() or
// via LocationManager.getLastLocation().
Location location = getFreshLocationLocked();
// Update all fences.
// Keep track of the distance to the nearest fence.
double minFenceDistance = Double.MAX_VALUE;
boolean needUpdates = false;
for (GeofenceState state : mFences) {
if (mBlacklist.isBlacklisted(state.mPackageName)) {
if (D) {
Slog.d(TAG, "skipping geofence processing for blacklisted app: "
+ state.mPackageName);
}
continue;
}
int op = LocationManagerService.resolutionLevelToOp(state.mAllowedResolutionLevel);
if (op >= 0) {
if (mAppOps.noteOpNoThrow(AppOpsManager.OP_FINE_LOCATION, state.mUid,
state.mPackageName) != AppOpsManager.MODE_ALLOWED) {
if (D) {
Slog.d(TAG, "skipping geofence processing for no op app: "
+ state.mPackageName);
}
continue;
}
}
needUpdates = true;
if (location != null) {
int event = state.processLocation(location);
if ((event & GeofenceState.FLAG_ENTER) != 0) {
enterIntents.add(state.mIntent);
}
if ((event & GeofenceState.FLAG_EXIT) != 0) {
exitIntents.add(state.mIntent);
}
// FIXME: Ideally this code should take into account the accuracy of the
// location fix that was used to calculate the distance in the first place.
double fenceDistance = state.getDistanceToBoundary(); // MAX_VALUE if unknown
if (fenceDistance < minFenceDistance) {
minFenceDistance = fenceDistance;
}
}
}
// Request or cancel location updates if needed.
if (needUpdates) {
// Request location updates.
// Compute a location update interval based on the distance to the nearest fence.
long intervalMs;
if (location != null && Double.compare(minFenceDistance, Double.MAX_VALUE) != 0) {
intervalMs = (long)Math.min(MAX_INTERVAL_MS, Math.max(MIN_INTERVAL_MS,
minFenceDistance * 1000 / MAX_SPEED_M_S));
} else {
intervalMs = MIN_INTERVAL_MS;
}
if (!mReceivingLocationUpdates || mLocationUpdateInterval != intervalMs) {
mReceivingLocationUpdates = true;
mLocationUpdateInterval = intervalMs;
mLastLocationUpdate = location;
LocationRequest request = new LocationRequest();
request.setInterval(intervalMs).setFastestInterval(0);
mLocationManager.requestLocationUpdates(request, this, mHandler.getLooper());
}
} else {
// Cancel location updates.
if (mReceivingLocationUpdates) {
mReceivingLocationUpdates = false;
mLocationUpdateInterval = 0;
mLastLocationUpdate = null;
mLocationManager.removeUpdates(this);
}
}
if (D) {
Slog.d(TAG, "updateFences: location=" + location
+ ", mFences.size()=" + mFences.size()
+ ", mReceivingLocationUpdates=" + mReceivingLocationUpdates
+ ", mLocationUpdateInterval=" + mLocationUpdateInterval
+ ", mLastLocationUpdate=" + mLastLocationUpdate);
}
}
// release lock before sending intents
for (PendingIntent intent : exitIntents) {
sendIntentExit(intent);
}
for (PendingIntent intent : enterIntents) {
sendIntentEnter(intent);
}
}
private void sendIntentEnter(PendingIntent pendingIntent) {
if (D) {
Slog.d(TAG, "sendIntentEnter: pendingIntent=" + pendingIntent);
}
Intent intent = new Intent();
intent.putExtra(LocationManager.KEY_PROXIMITY_ENTERING, true);
sendIntent(pendingIntent, intent);
}
private void sendIntentExit(PendingIntent pendingIntent) {
if (D) {
Slog.d(TAG, "sendIntentExit: pendingIntent=" + pendingIntent);
}
Intent intent = new Intent();
intent.putExtra(LocationManager.KEY_PROXIMITY_ENTERING, false);
sendIntent(pendingIntent, intent);
}
private void sendIntent(PendingIntent pendingIntent, Intent intent) {
mWakeLock.acquire();
try {
pendingIntent.send(mContext, 0, intent, this, null,
android.Manifest.permission.ACCESS_FINE_LOCATION);
} catch (PendingIntent.CanceledException e) {
removeFence(null, pendingIntent);
mWakeLock.release();
}
// ...otherwise, mWakeLock.release() gets called by onSendFinished()
}
// Runs on the handler (which was passed into LocationManager.requestLocationUpdates())
@Override
public void onLocationChanged(Location location) {
synchronized (mLock) {
if (mReceivingLocationUpdates) {
mLastLocationUpdate = location;
}
// Update the fences immediately before returning in
// case the caller is holding a wakelock.
if (mPendingUpdate) {
mHandler.removeMessages(MSG_UPDATE_FENCES);
} else {
mPendingUpdate = true;
}
}
updateFences();
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) { }
@Override
public void onProviderEnabled(String provider) { }
@Override
public void onProviderDisabled(String provider) { }
@Override
public void onSendFinished(PendingIntent pendingIntent, Intent intent, int resultCode,
String resultData, Bundle resultExtras) {
mWakeLock.release();
}
public void dump(PrintWriter pw) {
pw.println(" Geofences:");
for (GeofenceState state : mFences) {
pw.append(" ");
pw.append(state.mPackageName);
pw.append(" ");
pw.append(state.mFence.toString());
pw.append("\n");
}
}
private final class GeofenceHandler extends Handler {
public GeofenceHandler() {
super(true /*async*/);
}
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MSG_UPDATE_FENCES: {
updateFences();
break;
}
}
}
}
}
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