Avoid NPE in GpsLocationProvider

Oops, looks like we were spinning up a secondary thread to run some
tasks that will just happen on the main thread regardless. Removed
the secondary thread and fixed up initialisation order regarding
mHandler and things that post to it. Also reordered GPS and
PASSIVE provider initialisation order since GPS depends on PASSIVE.

This should be both safer and easier to read.

Bug: 7248029
Change-Id: I8630caf0a7bd1b2c401603075676f13dda5be4fa

Author: Victoria Lease

services/java/com/android/server/LocationManagerService.java

@@ -228,6 +228,12 @@ public void onChange(boolean selfChange) {
     }
 
     private void loadProvidersLocked() {
+        // create a passive location provider, which is always enabled
+        PassiveProvider passiveProvider = new PassiveProvider(this);
+        addProviderLocked(passiveProvider);
+        mEnabledProviders.add(passiveProvider.getName());
+        mPassiveProvider = passiveProvider;
+
         if (GpsLocationProvider.isSupported()) {
             // Create a gps location provider
             GpsLocationProvider gpsProvider = new GpsLocationProvider(mContext, this);
@@ -237,12 +243,6 @@ private void loadProvidersLocked() {
             mRealProviders.put(LocationManager.GPS_PROVIDER, gpsProvider);
         }
 
-        // create a passive location provider, which is always enabled
-        PassiveProvider passiveProvider = new PassiveProvider(this);
-        addProviderLocked(passiveProvider);
-        mEnabledProviders.add(passiveProvider.getName());
-        mPassiveProvider = passiveProvider;
-
         /*
         Load package name(s) containing location provider support.
         These packages can contain services implementing location providers:

services/java/com/android/server/location/GpsLocationProvider.java

@@ -40,10 +40,8 @@
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.IBinder;
-import android.os.Looper;
 import android.os.Message;
 import android.os.PowerManager;
-import android.os.Process;
 import android.os.RemoteException;
 import android.os.ServiceManager;
 import android.os.SystemClock;
@@ -75,7 +73,6 @@
 import java.util.Date;
 import java.util.Map.Entry;
 import java.util.Properties;
-import java.util.concurrent.CountDownLatch;
 
 /**
  * A GPS implementation of LocationProvider used by LocationManager.
@@ -287,12 +284,8 @@ public GpsRequest(ProviderRequest request, WorkSource source) {
     private Bundle mLocationExtras = new Bundle();
     private ArrayList<Listener> mListeners = new ArrayList<Listener>();
 
-    // GpsLocationProvider's handler thread
-    private final Thread mThread;
-    // Handler for processing events in mThread.
+    // Handler for processing events
     private Handler mHandler;
-    // Used to signal when our main thread has initialized everything
-    private final CountDownLatch mInitializedLatch = new CountDownLatch(1);
 
     private String mAGpsApn;
     private int mAGpsDataConnectionState;
@@ -437,21 +430,6 @@ public GpsLocationProvider(Context context, ILocationManager ilocationManager) {
         mWakeupIntent = PendingIntent.getBroadcast(mContext, 0, new Intent(ALARM_WAKEUP), 0);
         mTimeoutIntent = PendingIntent.getBroadcast(mContext, 0, new Intent(ALARM_TIMEOUT), 0);
 
-        IntentFilter intentFilter = new IntentFilter();
-        intentFilter.addAction(Intents.DATA_SMS_RECEIVED_ACTION);
-        intentFilter.addDataScheme("sms");
-        intentFilter.addDataAuthority("localhost","7275");
-        context.registerReceiver(mBroadcastReciever, intentFilter);
-
-        intentFilter = new IntentFilter();
-        intentFilter.addAction(Intents.WAP_PUSH_RECEIVED_ACTION);
-        try {
-            intentFilter.addDataType("application/vnd.omaloc-supl-init");
-        } catch (IntentFilter.MalformedMimeTypeException e) {
-            Log.w(TAG, "Malformed SUPL init mime type");
-        }
-        context.registerReceiver(mBroadcastReciever, intentFilter);
-
         mConnMgr = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
 
         // Battery statistics service to be notified when GPS turns on or off
@@ -487,26 +465,43 @@ public GpsLocationProvider(Context context, ILocationManager ilocationManager) {
             Log.w(TAG, "Could not open GPS configuration file " + PROPERTIES_FILE);
         }
 
-        // wait until we are fully initialized before returning
-        mThread = new GpsLocationProviderThread();
-        mThread.start();
-        while (true) {
-            try {
-                mInitializedLatch.await();
-                break;
-            } catch (InterruptedException e) {
-                Thread.currentThread().interrupt();
+        // construct handler, listen for events
+        mHandler = new ProviderHandler();
+        listenForBroadcasts();
+
+        // also listen for PASSIVE_PROVIDER updates
+        mHandler.post(new Runnable() {
+            @Override
+            public void run() {
+                LocationManager locManager =
+                        (LocationManager) mContext.getSystemService(Context.LOCATION_SERVICE);
+                locManager.requestLocationUpdates(LocationManager.PASSIVE_PROVIDER,
+                        0, 0, new NetworkLocationListener(), mHandler.getLooper());                
             }
-        }
+        });
     }
 
-    private void initialize() {
-        // register our receiver on our thread rather than the main thread
+    private void listenForBroadcasts() {
         IntentFilter intentFilter = new IntentFilter();
+        intentFilter.addAction(Intents.DATA_SMS_RECEIVED_ACTION);
+        intentFilter.addDataScheme("sms");
+        intentFilter.addDataAuthority("localhost","7275");
+        mContext.registerReceiver(mBroadcastReciever, intentFilter, null, mHandler);
+
+        intentFilter = new IntentFilter();
+        intentFilter.addAction(Intents.WAP_PUSH_RECEIVED_ACTION);
+        try {
+            intentFilter.addDataType("application/vnd.omaloc-supl-init");
+        } catch (IntentFilter.MalformedMimeTypeException e) {
+            Log.w(TAG, "Malformed SUPL init mime type");
+        }
+        mContext.registerReceiver(mBroadcastReciever, intentFilter, null, mHandler);
+
+        intentFilter = new IntentFilter();
         intentFilter.addAction(ALARM_WAKEUP);
         intentFilter.addAction(ALARM_TIMEOUT);
         intentFilter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
-        mContext.registerReceiver(mBroadcastReciever, intentFilter);
+        mContext.registerReceiver(mBroadcastReciever, intentFilter, null, mHandler);
     }
 
     /**
@@ -1536,29 +1531,6 @@ public void handleMessage(Message msg) {
         }
     };
 
-    private final class GpsLocationProviderThread extends Thread {
-
-        public GpsLocationProviderThread() {
-            super("GpsLocationProvider");
-        }
-
-        @Override
-        public void run() {
-            Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
-            initialize();
-            Looper.prepare();
-
-            LocationManager locManager =
-                    (LocationManager) mContext.getSystemService(Context.LOCATION_SERVICE);
-            mHandler = new ProviderHandler();
-            // signal when we are initialized and ready to go
-            mInitializedLatch.countDown();
-            locManager.requestLocationUpdates(LocationManager.PASSIVE_PROVIDER,
-                    0, 0, new NetworkLocationListener(), Looper.myLooper());
-            Looper.loop();
-        }
-    }
-
     private final class NetworkLocationListener implements LocationListener {
         @Override
         public void onLocationChanged(Location location) {