Geolocation Android: split LocationProviderAndroid out of LocationProviderFactory

device/geolocation/android/java/src/org/chromium/device/geolocation/LocationProviderAndroid.java

+// Copyright 2017 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.device.geolocation;
+
+import android.content.Context;
+import android.location.Criteria;
+import android.location.Location;
+import android.location.LocationListener;
+import android.location.LocationManager;
+import android.os.Bundle;
+
+import org.chromium.base.Log;
+import org.chromium.base.ThreadUtils;
+
+import java.util.List;
+
+/**
+ * This is a LocationProvider using Android APIs [1]. It is a separate class for clarity
+ * so that it can manage all processing completely on the UI thread. The container class
+ * ensures that the start/stop calls into this class are done on the UI thread.
+ *
+ * [1] https://developer.android.com/reference/android/location/package-summary.html
+ */
+public class LocationProviderAndroid
+        implements LocationListener, LocationProviderFactory.LocationProvider {
+    private static final String TAG = "cr_LocationProvider";
+
+    private Context mContext;
+    private LocationManager mLocationManager;
+    private boolean mIsRunning;
+
+    LocationProviderAndroid(Context context) {
+        mContext = context;
+    }
+
+    @Override
+    public void start(boolean enableHighAccuracy) {
+        unregisterFromLocationUpdates();
+        registerForLocationUpdates(enableHighAccuracy);
+    }
+
+    @Override
+    public void stop() {
+        unregisterFromLocationUpdates();
+    }
+
+    @Override
+    public boolean isRunning() {
+        return mIsRunning;
+    }
+
+    @Override
+    public void onLocationChanged(Location location) {
+        // Callbacks from the system location service are queued to this thread, so it's
+        // possible that we receive callbacks after unregistering. At this point, the
+        // native object will no longer exist.
+        if (mIsRunning) {
+            updateNewLocation(location);
+        }
+    }
+
+    @Override
+    public void onStatusChanged(String provider, int status, Bundle extras) {}
+
+    @Override
+    public void onProviderEnabled(String provider) {}
+
+    @Override
+    public void onProviderDisabled(String provider) {}
+
+    private void ensureLocationManagerCreated() {
+        if (mLocationManager != null) return;
+        mLocationManager = (LocationManager) mContext.getSystemService(Context.LOCATION_SERVICE);
+        if (mLocationManager == null) {
+            Log.e(TAG, "Could not get location manager.");
+        }
+    }
+
+    /**
+     * Registers this object with the location service.
+     */
+    private void registerForLocationUpdates(boolean enableHighAccuracy) {
+        ensureLocationManagerCreated();
+        if (usePassiveOneShotLocation()) return;
+
+        assert !mIsRunning;
+        mIsRunning = true;
+
+        // We're running on the main thread. The C++ side is responsible to
+        // bounce notifications to the Geolocation thread as they arrive in the mainLooper.
+        try {
+            Criteria criteria = new Criteria();
+            if (enableHighAccuracy) criteria.setAccuracy(Criteria.ACCURACY_FINE);
+            mLocationManager.requestLocationUpdates(
+                    0, 0, criteria, this, ThreadUtils.getUiThreadLooper());
+        } catch (SecurityException e) {
+            Log.e(TAG,
+                    "Caught security exception while registering for location updates "
+                            + "from the system. The application does not have sufficient "
+                            + "geolocation permissions.");
+            unregisterFromLocationUpdates();
+            // Propagate an error to JavaScript, this can happen in case of WebView
+            // when the embedding app does not have sufficient permissions.
+            LocationProviderAdapter.newErrorAvailable("application does not have sufficient "
+                    + "geolocation permissions.");
+        } catch (IllegalArgumentException e) {
+            Log.e(TAG, "Caught IllegalArgumentException registering for location updates.");
+            unregisterFromLocationUpdates();
+            assert false;
+        }
+    }
+
+    /**
+     * Unregisters this object from the location service.
+     */
+    private void unregisterFromLocationUpdates() {
+        if (mIsRunning) {
+            mIsRunning = false;
+            mLocationManager.removeUpdates(this);
+        }
+    }
+
+    private void updateNewLocation(Location location) {
+        LocationProviderAdapter.newLocationAvailable(location.getLatitude(),
+                location.getLongitude(), location.getTime() / 1000.0, location.hasAltitude(),
+                location.getAltitude(), location.hasAccuracy(), location.getAccuracy(),
+                location.hasBearing(), location.getBearing(), location.hasSpeed(),
+                location.getSpeed());
+    }
+
+    private boolean usePassiveOneShotLocation() {
+        if (!isOnlyPassiveLocationProviderEnabled()) return false;
+
+        // Do not request a location update if the only available location provider is
+        // the passive one. Make use of the last known location and call
+        // onLocationChanged directly.
+        final Location location =
+                mLocationManager.getLastKnownLocation(LocationManager.PASSIVE_PROVIDER);
+        if (location != null) {
+            ThreadUtils.runOnUiThread(new Runnable() {
+                @Override
+                public void run() {
+                    updateNewLocation(location);
+                }
+            });
+        }
+        return true;
+    }
+
+    /*
+     * Checks if the passive location provider is the only provider available
+     * in the system.
+     */
+    private boolean isOnlyPassiveLocationProviderEnabled() {
+        List<String> providers = mLocationManager.getProviders(true);
+        return providers != null && providers.size() == 1
+                && providers.get(0).equals(LocationManager.PASSIVE_PROVIDER);
+    }
+}