Skip to content

Commit

Permalink
Merge branch 'master' into no-scanning-restarts-on-duplicate-detectio…
Browse files Browse the repository at this point in the history 
…n-devices
  • Loading branch information
@davidgyoung
davidgyoung committed Apr 21, 2017
2 parents c1dacc9 + ef90455 commit 1e49cd6
Show file tree
Hide file tree
Showing 7 changed files with 118 additions and 58 deletions.
5 changes: 5 additions & 0 deletions CHANGELOG.md
View file
Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,11 @@ Bug Fixes:
- Deprecate misspelled methods `removeMonitoreNotifier` and
`setRegionStatePeristenceEnabled` in favor of correctly spelled alternatives.
(#461, Marco Salis)
- Fix bug causing brief scan dropouts after starting a scan after a long period
of inactivity (i.e. startup and background-foreground transitions) due to
Android N scan limits (#489, Aaron Kromer)
- Ensure thread safety for singleton creation of `BeaconManager`,
`DetectionTracker`, `MonitoringStatus`, and `Stats`. (#494, Aaron Kromer)


### 2.9.2 / 2016-11-22
Expand Down
93 changes: 63 additions & 30 deletions src/main/java/org/altbeacon/beacon/BeaconManager.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -108,7 +108,7 @@
public class BeaconManager {
private static final String TAG = "BeaconManager";
private Context mContext;
protected static BeaconManager client = null;
protected static volatile BeaconManager client = null;
private final ConcurrentMap<BeaconConsumer, ConsumerInfo> consumers = new ConcurrentHashMap<BeaconConsumer,ConsumerInfo>();
private Messenger serviceMessenger = null;
protected final Set<RangeNotifier> rangeNotifiers = new CopyOnWriteArraySet<>();
Expand All @@ -123,6 +123,11 @@ public class BeaconManager {
private static boolean sAndroidLScanningDisabled = false;
private static boolean sManifestCheckingDisabled = false;

/**
* Private lock object for singleton initialization protecting against denial-of-service attack.
*/
private static final Object SINGLETON_LOCK = new Object();

/**
* Set to true if you want to show library debugging.
*
Expand Down Expand Up @@ -239,11 +244,29 @@ public static long getRegionExitPeriod(){
* or non-Service class, you can attach it to another singleton or a subclass of the Android Application class.
*/
public static BeaconManager getInstanceForApplication(Context context) {
if (client == null) {
LogManager.d(TAG, "BeaconManager instance creation");
client = new BeaconManager(context);
/*
* Follow double check pattern from Effective Java v2 Item 71.
*
* Bloch recommends using the local variable for this for performance reasons:
*
* > What this variable does is ensure that `field` is read only once in the common case
* > where it's already initialized. While not strictly necessary, this may improve
* > performance and is more elegant by the standards applied to low-level concurrent
* > programming. On my machine, [this] is about 25 percent faster than the obvious
* > version without a local variable.
*
* Joshua Bloch. Effective Java, Second Edition. Addison-Wesley, 2008. pages 283-284
*/
BeaconManager instance = client;
if (instance == null) {
synchronized (SINGLETON_LOCK) {
instance = client;
if (instance == null) {
client = instance = new BeaconManager(context);
}
}
}
return client;
return instance;
}

protected BeaconManager(Context context) {
Expand Down Expand Up @@ -271,17 +294,10 @@ public List<BeaconParser> getBeaconParsers() {
*/
@TargetApi(18)
public boolean checkAvailability() throws BleNotAvailableException {
if (android.os.Build.VERSION.SDK_INT < 18) {
if (!isBleAvailable()) {
throw new BleNotAvailableException("Bluetooth LE not supported by this device");
}
if (!mContext.getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {
throw new BleNotAvailableException("Bluetooth LE not supported by this device");
} else {
if (((BluetoothManager) mContext.getSystemService(Context.BLUETOOTH_SERVICE)).getAdapter().isEnabled()) {
return true;
}
}
return false;
return ((BluetoothManager) mContext.getSystemService(Context.BLUETOOTH_SERVICE)).getAdapter().isEnabled();
}

/**
Expand All @@ -292,8 +308,12 @@ public boolean checkAvailability() throws BleNotAvailableException {
* @param consumer the <code>Activity</code> or <code>Service</code> that will receive the callback when the service is ready.
*/
public void bind(BeaconConsumer consumer) {
if (android.os.Build.VERSION.SDK_INT < 18) {
LogManager.w(TAG, "Not supported prior to API 18. Method invocation will be ignored");
if (!isBleAvailable()) {
LogManager.w(TAG, "Method invocation will be ignored.");
return;
}
if (!mContext.getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {
LogManager.w(TAG, "This device does not support bluetooth LE. Will not start beacon scanning.");
return;
}
synchronized (consumers) {
Expand All @@ -318,8 +338,8 @@ public void bind(BeaconConsumer consumer) {
* @param consumer the <code>Activity</code> or <code>Service</code> that no longer needs to use the service.
*/
public void unbind(BeaconConsumer consumer) {
if (android.os.Build.VERSION.SDK_INT < 18) {
LogManager.w(TAG, "Not supported prior to API 18. Method invocation will be ignored");
if (!isBleAvailable()) {
LogManager.w(TAG, "Method invocation will be ignored.");
return;
}
synchronized (consumers) {
Expand Down Expand Up @@ -391,8 +411,9 @@ public boolean isAnyConsumerBound() {
* @see #setBackgroundBetweenScanPeriod(long p)
*/
public void setBackgroundMode(boolean backgroundMode) {
if (android.os.Build.VERSION.SDK_INT < 18) {
LogManager.w(TAG, "Not supported prior to API 18. Method invocation will be ignored");
if (!isBleAvailable()) {
LogManager.w(TAG, "Method invocation will be ignored.");
return;
}
mBackgroundModeUninitialized = false;
if (backgroundMode != mBackgroundMode) {
Expand Down Expand Up @@ -608,8 +629,8 @@ public void requestStateForRegion(Region region) {
*/
@TargetApi(18)
public void startRangingBeaconsInRegion(Region region) throws RemoteException {
if (android.os.Build.VERSION.SDK_INT < 18) {
LogManager.w(TAG, "Not supported prior to API 18. Method invocation will be ignored");
if (!isBleAvailable()) {
LogManager.w(TAG, "Method invocation will be ignored.");
return;
}
if (serviceMessenger == null) {
Expand All @@ -636,8 +657,8 @@ public void startRangingBeaconsInRegion(Region region) throws RemoteException {
*/
@TargetApi(18)
public void stopRangingBeaconsInRegion(Region region) throws RemoteException {
if (android.os.Build.VERSION.SDK_INT < 18) {
LogManager.w(TAG, "Not supported prior to API 18. Method invocation will be ignored");
if (!isBleAvailable()) {
LogManager.w(TAG, "Method invocation will be ignored.");
return;
}
if (serviceMessenger == null) {
Expand Down Expand Up @@ -671,8 +692,8 @@ public void stopRangingBeaconsInRegion(Region region) throws RemoteException {
*/
@TargetApi(18)
public void startMonitoringBeaconsInRegion(Region region) throws RemoteException {
if (android.os.Build.VERSION.SDK_INT < 18) {
LogManager.w(TAG, "Not supported prior to API 18. Method invocation will be ignored");
if (!isBleAvailable()) {
LogManager.w(TAG, "Method invocation will be ignored.");
return;
}
if (serviceMessenger == null) {
Expand All @@ -699,8 +720,8 @@ public void startMonitoringBeaconsInRegion(Region region) throws RemoteException
*/
@TargetApi(18)
public void stopMonitoringBeaconsInRegion(Region region) throws RemoteException {
if (android.os.Build.VERSION.SDK_INT < 18) {
LogManager.w(TAG, "Not supported prior to API 18. Method invocation will be ignored");
if (!isBleAvailable()) {
LogManager.w(TAG, "Method invocation will be ignored.");
return;
}
if (serviceMessenger == null) {
Expand All @@ -721,8 +742,8 @@ public void stopMonitoringBeaconsInRegion(Region region) throws RemoteException
*/
@TargetApi(18)
public void updateScanPeriods() throws RemoteException {
if (android.os.Build.VERSION.SDK_INT < 18) {
LogManager.w(TAG, "Not supported prior to API 18. Method invocation will be ignored");
if (!isBleAvailable()) {
LogManager.w(TAG, "Method invocation will be ignored.");
return;
}
if (serviceMessenger == null) {
Expand Down Expand Up @@ -895,6 +916,18 @@ public void setNonBeaconLeScanCallback(NonBeaconLeScanCallback callback) {
mNonBeaconLeScanCallback = callback;
}

private boolean isBleAvailable() {
boolean available = false;
if (android.os.Build.VERSION.SDK_INT < android.os.Build.VERSION_CODES.JELLY_BEAN_MR2) {
LogManager.w(TAG, "Bluetooth LE not supported prior to API 18.");
} else if (!mContext.getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {
LogManager.w(TAG, "This device does not support bluetooth LE.");
} else {
available = true;
}
return available;
}

private long getScanPeriod() {
if (mBackgroundMode) {
return backgroundScanPeriod;
Expand Down
2 changes: 1 addition & 1 deletion src/main/java/org/altbeacon/beacon/powersave/BackgroundPowerSaver.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -44,8 +44,8 @@ public BackgroundPowerSaver(Context context) {
LogManager.w(TAG, "BackgroundPowerSaver requires API 18 or higher.");
return;
}
((Application)context.getApplicationContext()).registerActivityLifecycleCallbacks(this);
beaconManager = BeaconManager.getInstanceForApplication(context);
((Application)context.getApplicationContext()).registerActivityLifecycleCallbacks(this);
}

@Override
Expand Down
10 changes: 4 additions & 6 deletions src/main/java/org/altbeacon/beacon/service/DetectionTracker.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -6,16 +6,14 @@
* Created by dyoung on 1/10/15.
*/
public class DetectionTracker {
private static DetectionTracker sDetectionTracker = null;
private static final DetectionTracker INSTANCE = new DetectionTracker();

private long mLastDetectionTime = 0l;
private DetectionTracker() {

}
public static synchronized DetectionTracker getInstance() {
if (sDetectionTracker == null) {
sDetectionTracker = new DetectionTracker();
}
return sDetectionTracker;
public static DetectionTracker getInstance() {
return INSTANCE;
}
public long getLastDetectionTime() {
return mLastDetectionTime;
Expand Down
32 changes: 26 additions & 6 deletions src/main/java/org/altbeacon/beacon/service/MonitoringStatus.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,7 @@
import static android.content.Context.MODE_PRIVATE;

public class MonitoringStatus {
private static MonitoringStatus sInstance;
private static volatile MonitoringStatus sInstance;
private static final int MAX_REGIONS_FOR_STATUS_PRESERVATION = 50;
private static final int MAX_STATUS_PRESERVATION_FILE_AGE_TO_RESTORE_SECS = 60 * 15;
private static final String TAG = MonitoringStatus.class.getSimpleName();
Expand All @@ -35,15 +35,35 @@ public class MonitoringStatus {

private boolean mStatePreservationIsOn = true;

/**
* Private lock object for singleton initialization protecting against denial-of-service attack.
*/
private static final Object SINGLETON_LOCK = new Object();

public static MonitoringStatus getInstanceForApplication(Context context) {
if (sInstance == null) {
synchronized (MonitoringStatus.class) {
if (sInstance == null) {
sInstance = new MonitoringStatus(context.getApplicationContext());
/*
* Follow double check pattern from Effective Java v2 Item 71.
*
* Bloch recommends using the local variable for this for performance reasons:
*
* > What this variable does is ensure that `field` is read only once in the common case
* > where it's already initialized. While not strictly necessary, this may improve
* > performance and is more elegant by the standards applied to low-level concurrent
* > programming. On my machine, [this] is about 25 percent faster than the obvious
* > version without a local variable.
*
* Joshua Bloch. Effective Java, Second Edition. Addison-Wesley, 2008. pages 283-284
*/
MonitoringStatus instance = sInstance;
if (instance == null) {
synchronized (SINGLETON_LOCK) {
instance = sInstance;
if (instance == null) {
sInstance = instance = new MonitoringStatus(context.getApplicationContext());
}
}
}
return sInstance;
return instance;
}

public MonitoringStatus(Context context) {
Expand Down
20 changes: 14 additions & 6 deletions src/main/java/org/altbeacon/beacon/service/Stats.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,12 @@
* Created by dyoung on 10/16/14.
*/
public class Stats {
private static final Stats INSTANCE = new Stats();
private static final String TAG = "Stats";

/**
* Synchronize all usage as this is not a thread safe class.
*/
private static final SimpleDateFormat SIMPLE_DATE_FORMAT = new SimpleDateFormat("HH:mm:ss.SSS");

private ArrayList<Sample> mSamples;
Expand All @@ -21,14 +26,11 @@ public class Stats {
private boolean mEnableHistoricalLogging;
private boolean mEnabled;
private Sample mSample;
private static Stats mInstance;

public static Stats getInstance() {
if(mInstance == null) {
mInstance = new Stats();
}
return mInstance;
return INSTANCE;
}

private Stats() {
mSampleIntervalMillis = 0l;
clearSamples();
Expand Down Expand Up @@ -105,7 +107,13 @@ private void logSample(Sample sample, boolean showHeader) {
}

private String formattedDate(Date d) {
return d == null ? "" : SIMPLE_DATE_FORMAT.format(d);
String formattedDate = "";
if (d != null) {
synchronized (SIMPLE_DATE_FORMAT) {
formattedDate = SIMPLE_DATE_FORMAT.format(d);
}
}
return formattedDate;
}

private void logSamples() {
Expand Down
14 changes: 5 additions & 9 deletions src/main/java/org/altbeacon/beacon/service/scanner/CycledLeScanner.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,6 @@ public abstract class CycledLeScanner {
private long mLastScanCycleEndTime = 0l;
protected long mNextScanCycleStartTime = 0l;
private long mScanCycleStopTime = 0l;
private long mLastScanStopTime = 0l;

private boolean mScanning;
protected boolean mScanningPaused;
Expand Down Expand Up @@ -158,10 +157,8 @@ public void stop() {
mScanningEnabled = false;
if (mScanCyclerStarted) {
scanLeDevice(false);
}
if (mBluetoothAdapter != null) {
stopScan();
mLastScanCycleEndTime = SystemClock.elapsedRealtime();
} else {
LogManager.d(TAG, "scanning already stopped");
}
}

Expand Down Expand Up @@ -289,23 +286,22 @@ private void finishScanCycle() {
// packets in the same cycle, we will not restart scanning and just keep it
// going.
if (!getDistinctPacketsDetectedPerScan()) {
long now = System.currentTimeMillis();
long now = SystemClock.elapsedRealtime();
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.N &&
mBetweenScanPeriod+mScanPeriod < ANDROID_N_MIN_SCAN_CYCLE_MILLIS &&
now-mLastScanStopTime < ANDROID_N_MIN_SCAN_CYCLE_MILLIS) {
now-mLastScanCycleStartTime < ANDROID_N_MIN_SCAN_CYCLE_MILLIS) {
// As of Android N, only 5 scans may be started in a 30 second period (6
// seconds per cycle) otherwise they are blocked. So we check here to see
// if the scan period is 6 seconds or less, and if we last stopped scanning
// fewer than 6 seconds ag and if so, we simply do not stop scanning
LogManager.d(TAG, "Not stopping scan because this is Android N and we" +
" keep scanning for a minimum of 6 seconds at a time. "+
"We will stop in "+(ANDROID_N_MIN_SCAN_CYCLE_MILLIS-(now-mLastScanStopTime))+" millisconds.");
"We will stop in "+(ANDROID_N_MIN_SCAN_CYCLE_MILLIS-(now-mLastScanCycleStartTime))+" millisconds.");
}
else {
try {
LogManager.d(TAG, "stopping bluetooth le scan");
finishScan();
mLastScanStopTime = now;
} catch (Exception e) {
LogManager.w(e, TAG, "Internal Android exception scanning for beacons");
}
Expand Down

0 comments on commit 1e49cd6

Please sign in to comment.