Add a mechanism to pause and resume geolocation requests.

content/public/android/java/src/org/chromium/content/browser/LocationProvider.java

-// Copyright 2012 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.content.browser;
-
-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 android.util.Log;
-
-import org.chromium.base.ActivityStatus;
-import org.chromium.base.CalledByNative;
-import org.chromium.base.ThreadUtils;
-
-import java.util.List;
-import java.util.concurrent.FutureTask;
-
-/**
- * Implements the Java side of LocationProviderAndroid.
- * Delegates all real functionality to the inner class.
- * See detailed documentation on
- * content/browser/geolocation/android_location_api_adapter.h.
- * Based on android.webkit.GeolocationService.java
- */
-class LocationProvider {
-
-    // Log tag
-    private static final String TAG = "LocationProvider";
-
-    /**
-     * This is the core of android location provider. It is a separate class for clarity
-     * so that it can manage all processing completely in the UI thread. The container class
-     * ensures that the start/stop calls into this class are done in the UI thread.
-     */
-    private static class LocationProviderImpl
-            implements LocationListener, ActivityStatus.StateListener {
-
-        private Context mContext;
-        private LocationManager mLocationManager;
-        private boolean mIsRunning;
-        private boolean mShouldRunAfterActivityResume;
-        private boolean mIsGpsEnabled;
-
-        LocationProviderImpl(Context context) {
-            mContext = context;
-        }
-
-        @Override
-        public void onActivityStateChange(int state) {
-            if (state == ActivityStatus.PAUSED) {
-                mShouldRunAfterActivityResume |= mIsRunning;
-                unregisterFromLocationUpdates();
-            } else if (state == ActivityStatus.RESUMED) {
-                assert !mIsRunning;
-                if (mShouldRunAfterActivityResume) {
-                    registerForLocationUpdates();
-                }
-            }
-        }
-
-        /**
-         * Start listening for location updates.
-         * @param gpsEnabled Whether or not we're interested in high accuracy GPS.
-         */
-        private void start(boolean gpsEnabled) {
-            if (!mIsRunning && !mShouldRunAfterActivityResume) {
-                // Currently idle so start listening to activity status changes.
-                ActivityStatus.registerStateListener(this);
-            }
-            mIsGpsEnabled = gpsEnabled;
-
-            if (ActivityStatus.getState() != ActivityStatus.RESUMED) {
-                mShouldRunAfterActivityResume = true;
-            } else {
-                unregisterFromLocationUpdates();
-                registerForLocationUpdates();
-            }
-        }
-
-        /**
-         * Stop listening for location updates.
-         */
-        private void stop() {
-            unregisterFromLocationUpdates();
-            ActivityStatus.unregisterStateListener(this);
-            mShouldRunAfterActivityResume = false;
-        }
-
-        /**
-         * Returns true if we are currently listening for location updates, false if not.
-         */
-        private boolean isRunning() {
-            return mIsRunning;
-        }
-
-        @Override
-        public void onLocationChanged(Location location) {
-            // Callbacks from the system location sevice 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);
-            }
-        }
-
-        private void updateNewLocation(Location location) {
-            nativeNewLocationAvailable(location.getLatitude(), location.getLongitude(),
-                    location.getTime() / 1000.0,
-                    location.hasAltitude(), location.getAltitude(),
-                    location.hasAccuracy(), location.getAccuracy(),
-                    location.hasBearing(), location.getBearing(),
-                    location.hasSpeed(), location.getSpeed());
-        }
-
-        @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() {
-            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();
-                mLocationManager.requestLocationUpdates(0, 0, criteria, this,
-                        ThreadUtils.getUiThreadLooper());
-                if (mIsGpsEnabled) {
-                    criteria.setAccuracy(Criteria.ACCURACY_FINE);
-                    mLocationManager.requestLocationUpdates(0, 0, criteria, this,
-                            ThreadUtils.getUiThreadLooper());
-                }
-            } catch (SecurityException e) {
-                Log.e(TAG, "Caught security exception registering for location updates from " +
-                    "system. This should only happen in DumpRenderTree.");
-            } catch (IllegalArgumentException e) {
-                Log.e(TAG, "Caught IllegalArgumentException registering for location updates.");
-            }
-        }
-
-        /**
-         * Unregisters this object from the location service.
-         */
-        private void unregisterFromLocationUpdates() {
-            if (mIsRunning) {
-                mIsRunning = false;
-                mLocationManager.removeUpdates(this);
-            }
-        }
-
-        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);
-        }
-    }
-
-    // Delegate handling the real work in the main thread.
-    private LocationProviderImpl mImpl;
-
-    private LocationProvider(Context context) {
-        mImpl = new LocationProviderImpl(context);
-    }
-
-    @CalledByNative
-    static LocationProvider create(Context context) {
-        return new LocationProvider(context);
-    }
-
-    /**
-     * Start listening for location updates until we're told to quit. May be
-     * called in any thread.
-     * @param gpsEnabled Whether or not we're interested in high accuracy GPS.
-     */
-    @CalledByNative
-    public boolean start(final boolean gpsEnabled) {
-        FutureTask<Void> task = new FutureTask<Void>(new Runnable() {
-            @Override
-            public void run() {
-                mImpl.start(gpsEnabled);
-            }
-        }, null);
-        ThreadUtils.runOnUiThread(task);
-        return true;
-    }
-
-    /**
-     * Stop listening for location updates. May be called in any thread.
-     */
-    @CalledByNative
-    public void stop() {
-        FutureTask<Void> task = new FutureTask<Void>(new Runnable() {
-            @Override
-            public void run() {
-                mImpl.stop();
-            }
-        }, null);
-        ThreadUtils.runOnUiThread(task);
-    }
-
-    /**
-     * Returns true if we are currently listening for location updates, false if not.
-     * Must be called only in the UI thread.
-     */
-    public boolean isRunning() {
-        assert ThreadUtils.runningOnUiThread();
-        return mImpl.isRunning();
-    }
-
-    // Native functions
-    public static native void nativeNewLocationAvailable(
-            double latitude, double longitude, double timeStamp,
-            boolean hasAltitude, double altitude,
-            boolean hasAccuracy, double accuracy,
-            boolean hasHeading, double heading,
-            boolean hasSpeed, double speed);
-    public static native void nativeNewErrorAvailable(String message);
-}