Properly handling invalid track/point/waypoint IDs.

This makes the provider utils implementation return null for those cases, and fixes all callers which didn't check for that.

MyTracks/src/com/google/android/apps/mytracks/ChartActivity.java

@@ -144,6 +144,7 @@ public class ChartActivity extends Activity implements TrackDataListener {
 
     dataHub.registerTrackDataListener(this, EnumSet.of(
         ListenerDataType.SELECTED_TRACK_CHANGED,
+        ListenerDataType.TRACK_UPDATES,
         ListenerDataType.POINT_UPDATES,
         ListenerDataType.SAMPLED_OUT_POINT_UPDATES,
         ListenerDataType.WAYPOINT_UPDATES,
@@ -424,7 +425,7 @@ public class ChartActivity extends Activity implements TrackDataListener {
     this.metricUnits = metric;
 
     chartView.setMetricUnits(metric);
-    
+
     return true;  // Reload data
   }
 

MyTracks/src/com/google/android/apps/mytracks/ExportAllTracks.java

@@ -189,6 +189,11 @@ public class ExportAllTracks {
         Log.i(Constants.TAG, "ExportAllTracks: exporting: " + id);
         TrackWriter writer =
             TrackWriterFactory.newWriter(activity, providerUtils, id, format);
+        if (writer == null) {
+          showToast(R.string.error_track_does_not_exist, Toast.LENGTH_LONG);
+          return;
+        }
+
         writer.writeTrack();
 
         if (!writer.wasSuccess()) {

MyTracks/src/com/google/android/apps/mytracks/MyTracks.java

@@ -905,7 +905,7 @@ public class MyTracks extends TabActivity implements OnTouchListener,
    * Initiates the process to send tracks to google.
    * This is called once the user has selected sending options via the
    * SendToGoogleDialog.
-   * 
+   *
    * TODO: Change this whole flow to an actual state machine.
    */
   public void sendToGoogle() {
@@ -963,8 +963,12 @@ public class MyTracks extends TabActivity implements OnTouchListener,
           // Update the map id for this track:
           try {
             Track track = providerUtils.getTrack(trackId);
-            track.setMapId(mapId);
+            if (track != null) {
-            providerUtils.updateTrack(track);
+              track.setMapId(mapId);
+              providerUtils.updateTrack(track);
+            } else {
+              Log.w(TAG, "Updating map id failed.");
+            }
           } catch (RuntimeException e) {
             // If that fails whatever reasons we'll just log an error, but
             // continue.
@@ -1017,15 +1021,19 @@ public class MyTracks extends TabActivity implements OnTouchListener,
           // Update the table id for this track:
           try {
             Track track = providerUtils.getTrack(trackId);
-            track.setTableId(tableId);
+            if (track != null) {
-            providerUtils.updateTrack(track);
+              track.setTableId(tableId);
+              providerUtils.updateTrack(track);
+            } else {
+              Log.w(TAG, "Updating table id failed.");
+            }
           } catch (RuntimeException e) {
             // If that fails whatever reasons we'll just log an error, but
             // continue.
             Log.w(TAG, "Updating table id failed.", e);
           }
         }
-        
+
         onSendToFusionTablesDone();
       }
     };
@@ -1072,7 +1080,7 @@ public class MyTracks extends TabActivity implements OnTouchListener,
     Log.d(TAG, "Sending to Docs....");
     setProgressValue(50);
     setProgressMessage(R.string.progress_message_sending_docs);
-    final SendToDocs sender = new SendToDocs(this, 
+    final SendToDocs sender = new SendToDocs(this,
         authMap.get(SendToDocs.GDATA_SERVICE_NAME_TRIX),
         authMap.get(SendToDocs.GDATA_SERVICE_NAME_DOCLIST), trackId);
     sendToTrackId = trackId;
@@ -1228,6 +1236,11 @@ public class MyTracks extends TabActivity implements OnTouchListener,
    */
   public void saveTrack(long trackId, TrackFileFormat format) {
     TrackWriter writer = TrackWriterFactory.newWriter(this, providerUtils, trackId, format);
+    if (writer == null) {
+      dialogManager.showMessageDialog(R.string.error_track_does_not_exist, false);
+      return;
+    }
+
     WriteProgressController controller = new WriteProgressController(this, writer);
     controller.setOnCompletionListener(new WriteProgressController.OnCompletionListener() {
       @Override
@@ -1247,6 +1260,10 @@ public class MyTracks extends TabActivity implements OnTouchListener,
    */
   public void sendTrack(long trackId, final TrackFileFormat format) {
     TrackWriter writer = TrackWriterFactory.newWriter(this, providerUtils, trackId, format);
+    if (writer == null) {
+      dialogManager.showMessageDialog(R.string.error_track_does_not_exist, false);
+      return;
+    }
 
     FileUtils fileUtils = new FileUtils();
     String extension = format.getExtension();
@@ -1313,17 +1330,17 @@ public class MyTracks extends TabActivity implements OnTouchListener,
   long getRecordingTrackId() {
     return sharedPreferences.getLong(getString(R.string.recording_track_key), -1);
   }
-  
+
   // @VisibleForTesting
   SharedPreferences getSharedPreferences() {
     return sharedPreferences;
   }
-  
+
   // @VisibleForTesting
   static void clearInstance() {
     instance = null;
   }
-  
+
   // @VisibleForTesting
   ITrackRecordingService getTrackRecordingService() {
     return trackRecordingService;

MyTracks/src/com/google/android/apps/mytracks/WaypointsList.java

@@ -1,12 +1,12 @@
 /*
  * Copyright 2009 Google Inc.
- * 
+ *
  * 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
@@ -73,15 +73,18 @@ public class WaypointsList extends ListActivity
           contextPosition = info.position;
           waypointId = WaypointsList.this.listView.getAdapter()
               .getItemId(contextPosition);
-          int type = providerUtils.getWaypoint(info.id).getType();
+          Waypoint waypoint = providerUtils.getWaypoint(info.id);
-          menu.add(0, Constants.MENU_SHOW, 0,
+          if (waypoint != null) {
-              R.string.waypointslist_show_waypoint);
+            int type = waypoint.getType();
-          menu.add(0, Constants.MENU_EDIT, 0,
+            menu.add(0, Constants.MENU_SHOW, 0,
-              R.string.waypointslist_edit_waypoint);
+                R.string.waypointslist_show_waypoint);
-          menu.add(0, Constants.MENU_DELETE, 0,
+            menu.add(0, Constants.MENU_EDIT, 0,
-              R.string.waypointslist_delete_waypoint).setEnabled(
+                R.string.waypointslist_edit_waypoint);
-                  recordingTrackId < 0 || type == Waypoint.TYPE_WAYPOINT ||
+            menu.add(0, Constants.MENU_DELETE, 0,
-                  info.id != providerUtils.getLastWaypointId(recordingTrackId));
+                R.string.waypointslist_delete_waypoint).setEnabled(
+                    recordingTrackId < 0 || type == Waypoint.TYPE_WAYPOINT ||
+                    info.id != providerUtils.getLastWaypointId(recordingTrackId));
+          }
         }
       };
 
@@ -159,7 +162,7 @@ public class WaypointsList extends ListActivity
       trackId = -1;
     }
 
-    final long firstWaypointId = providerUtils.getFirstWaypointId(trackId); 
+    final long firstWaypointId = providerUtils.getFirstWaypointId(trackId);
     waypointsCursor = getContentResolver().query(
         WaypointsColumns.CONTENT_URI, null,
         WaypointsColumns.TRACKID + "=" + trackId + " AND "
@@ -209,7 +212,7 @@ public class WaypointsList extends ListActivity
         new String[] { WaypointsColumns.NAME, WaypointsColumns.TIME,
                        WaypointsColumns.CATEGORY, WaypointsColumns.TYPE },
         new int[] { R.id.waypointslist_item_name,
-                    R.id.waypointslist_item_time, 
+                    R.id.waypointslist_item_time,
                     R.id.waypointslist_item_category,
                     R.id.waypointslist_item_icon });
 
@@ -219,7 +222,7 @@ public class WaypointsList extends ListActivity
         waypointsCursor.getColumnIndexOrThrow(WaypointsColumns.TYPE);
     adapter.setViewBinder(new SimpleCursorAdapter.ViewBinder() {
       @Override
-      public boolean setViewValue(View view, Cursor cursor, int columnIndex) {    
+      public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
         if (columnIndex == timeIdx) {
           long time = cursor.getLong(timeIdx);
           TextView textView = (TextView) view;

MyTracks/src/com/google/android/apps/mytracks/content/TrackDataHub.java

@@ -17,10 +17,10 @@ package com.google.android.apps.mytracks.content;
 
 import static com.google.android.apps.mytracks.Constants.DEFAULT_MIN_REQUIRED_ACCURACY;
 import static com.google.android.apps.mytracks.Constants.MAX_DISPLAYED_WAYPOINTS_POINTS;
-import static com.google.android.apps.mytracks.Constants.TARGET_DISPLAYED_TRACK_POINTS;
 import static com.google.android.apps.mytracks.Constants.MAX_LOCATION_AGE_MS;
 import static com.google.android.apps.mytracks.Constants.MAX_NETWORK_AGE_MS;
 import static com.google.android.apps.mytracks.Constants.TAG;
+import static com.google.android.apps.mytracks.Constants.TARGET_DISPLAYED_TRACK_POINTS;
 
 import com.google.android.apps.mytracks.content.DataSourceManager.DataSourceListener;
 import com.google.android.apps.mytracks.content.MyTracksProviderUtils.DoubleBufferedLocationFactory;
@@ -40,7 +40,6 @@ import android.location.LocationManager;
 import android.os.Handler;
 import android.os.HandlerThread;
 import android.util.Log;
-import android.widget.Toast;
 
 import java.util.Collections;
 import java.util.EnumSet;
@@ -791,10 +790,6 @@ public class TrackDataHub {
       public void run() {
         for (TrackDataListener listener : listeners) {
           listener.onSelectedTrackChanged(track, isRecordingSelected());
-
-          if (track != null) {
-            listener.onTrackUpdated(track);
-          }
         }
       }
     });

MyTracks/src/com/google/android/apps/mytracks/io/SendToFusionTables.java

@@ -179,6 +179,11 @@ public class SendToFusionTables implements Runnable {
 
       // Get the track meta-data
       Track track = providerUtils.getTrack(trackId);
+      if (track == null) {
+        Log.w(Constants.TAG, "Cannot get track.");
+        return;
+      }
+
       String originalDescription = track.getDescription();
 
       // Create a new table:
@@ -207,7 +212,6 @@ public class SendToFusionTables implements Runnable {
       Log.d(Constants.TAG, "SendToFusionTables: Done: " + success);
       progressIndicator.setProgressValue(PROGRESS_COMPLETE);
     } finally {
-
       final boolean finalSuccess = success;
       final int finalStatusMessageId = statusMessageId;
       context.runOnUiThread(new Runnable() {
@@ -304,7 +308,7 @@ public class SendToFusionTables implements Runnable {
 
     Cursor locationsCursor = providerUtils.getLocationsCursor(track.getId(), 0, -1, false);
     try {
-      if (!locationsCursor.moveToFirst()) {
+      if (locationsCursor == null || !locationsCursor.moveToFirst()) {
         Log.w(Constants.TAG, "Unable to get any points to upload");
         return false;
       }
@@ -391,7 +395,9 @@ public class SendToFusionTables implements Runnable {
 
       return true;
     } finally {
-      locationsCursor.close();
+      if (locationsCursor != null) {
+        locationsCursor.close();
+      }
     }
   }
 

MyTracks/src/com/google/android/apps/mytracks/io/SendToMyMaps.java

@@ -1,12 +1,12 @@
 /*
  * Copyright 2008 Google Inc.
- * 
+ *
  * 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
@@ -76,7 +76,7 @@ public class SendToMyMaps implements Runnable {
   public interface OnSendCompletedListener {
     void onSendCompleted(String mapId, boolean success, int statusMessage);
   }
-  
+
   public SendToMyMaps(Activity context, String mapId, AuthManager auth,
       long trackId, ProgressIndicator progressIndicator,
       OnSendCompletedListener onCompletion) {
@@ -103,15 +103,20 @@ public class SendToMyMaps implements Runnable {
       progressIndicator.setProgressValue(1);
       progressIndicator.setProgressMessage(
           R.string.progress_message_reading_track);
-  
+
       // Get the track meta-data
       Track track = providerUtils.getTrack(trackId);
+      if (track == null) {
+        Log.w(Constants.TAG, "Cannot get track.");
+        return;
+      }
+
       String originalDescription = track.getDescription();
       track.setDescription("<p>" + track.getDescription() + "</p><p>"
           + stringUtils.generateTrackDescription(track, null, null) + "</p>");
 
       mapsClient = new MapsFacade(context, auth);
-  
+
       // Create a new map if necessary:
       boolean isNewMap = mapId.equals(NEW_MAP_ID);
       if (isNewMap) {
@@ -166,7 +171,7 @@ public class SendToMyMaps implements Runnable {
           Log.w(TAG, "SendToMyMaps: upload waypoints failed.");
         }
       }
-  
+
       if (success) {
         statusMessageId = isNewMap
             ? R.string.status_new_mymap_has_been_created
@@ -178,7 +183,7 @@ public class SendToMyMaps implements Runnable {
       if (mapsClient != null) {
         mapsClient.cleanUp();
       }
-  
+
       final boolean finalSuccess = success;
       final int finalStatusMessageId = statusMessageId;
       context.runOnUiThread(new Runnable() {
@@ -206,17 +211,17 @@ public class SendToMyMaps implements Runnable {
     Cursor locationsCursor =
         providerUtils.getLocationsCursor(track.getId(), 0, -1, false);
     try {
-      if (!locationsCursor.moveToFirst()) {
+      if (locationsCursor == null || !locationsCursor.moveToFirst()) {
         Log.w(TAG, "Unable to get any points to upload");
         return false;
       }
-  
+
       totalLocationsRead = 0;
       totalLocationsPrepared = 0;
       totalLocationsUploaded = 0;
       totalLocations = locationsCursor.getCount();
       totalSegmentsUploaded = 0;
-  
+
       // Limit the number of elevation readings. Ideally we would want around 250.
       int elevationSamplingFrequency =
           Math.max(1, (int) (totalLocations / 250.0));
@@ -224,12 +229,12 @@ public class SendToMyMaps implements Runnable {
             "Using elevation sampling factor: " + elevationSamplingFrequency
             + " on " + totalLocations);
       double totalDistance = 0;
-  
+
       Vector<Double> distances = new Vector<Double>();
       Vector<Double> elevations = new Vector<Double>();
       DoubleBuffer elevationBuffer =
           new DoubleBuffer(Constants.ELEVATION_SMOOTHING_FACTOR);
-  
+
       List<Location> locations = new ArrayList<Location>(MAX_POINTS_PER_UPLOAD);
       progressIndicator.setProgressMessage(
           R.string.progress_message_reading_track);
@@ -238,15 +243,15 @@ public class SendToMyMaps implements Runnable {
         if (totalLocationsRead % 100 == 0) {
           updateProgress();
         }
-  
+
         Location loc = providerUtils.createLocation(locationsCursor);
         locations.add(loc);
-  
+
         if (totalLocationsRead == 0) {
           // Put a marker at the first point of the first valid segment:
           mapsClient.uploadMarker(mapId, track.getName(), track.getDescription(), loc, true);
         }
-  
+
         // Add to the elevation profile.
         if (loc != null && LocationUtils.isValidLocation(loc)) {
           // All points go into the smoothing buffer...
@@ -256,19 +261,19 @@ public class SendToMyMaps implements Runnable {
             double dist = lastLocation.distanceTo(loc);
             totalDistance += dist;
           }
-  
+
           // ...but only a few points are really used to keep the url short.
           if (totalLocationsRead % elevationSamplingFrequency == 0) {
             distances.add(totalDistance);
             elevations.add(elevationBuffer.getAverage());
           }
         }
-  
+
         // If the location was not valid, it's a segment split, so make sure the
         // distance between the previous segment and the new one is not accounted
         // for in the next iteration.
         lastLocation = loc;
-  
+
         // Every now and then, upload the accumulated points
         if (totalLocationsRead % MAX_POINTS_PER_UPLOAD
             == MAX_POINTS_PER_UPLOAD - 1) {
@@ -276,28 +281,30 @@ public class SendToMyMaps implements Runnable {
             return false;
           }
         }
-  
+
         totalLocationsRead++;
       } while (locationsCursor.moveToNext());
-  
+
       // Do a final upload with what's left
       if (!prepareAndUploadPoints(track, locations)) {
         return false;
       }
-  
+
       // Put an end marker at the last point of the last valid segment:
       if (lastLocation != null) {
         track.setDescription("<p>" + originalDescription + "</p><p>"
             + stringUtils.generateTrackDescription(
                 track, distances, elevations)
             + "</p>");
-        return mapsClient.uploadMarker(mapId, track.getName(), track.getDescription(), 
+        return mapsClient.uploadMarker(mapId, track.getName(), track.getDescription(),
             lastLocation, false);
       }
-  
+
       return true;
     } finally {
-      locationsCursor.close();
+      if (locationsCursor != null) {
+        locationsCursor.close();
+      }
     }
   }
 
@@ -306,17 +313,17 @@ public class SendToMyMaps implements Runnable {
     progressIndicator.setProgressMessage(
         R.string.progress_message_preparing_track);
     updateProgress();
-  
+
     int numLocations = locations.size();
     if (numLocations < 2) {
       Log.d(TAG, "Not preparing/uploading too few points");
       totalLocationsUploaded += numLocations;
       return true;
     }
-  
+
     // Prepare/pre-process the points
     ArrayList<Track> splitTracks = prepareLocations(track, locations);
-  
+
     // Start uploading them
     progressIndicator.setProgressMessage(
         R.string.progress_message_sending_mymaps);
@@ -330,7 +337,7 @@ public class SendToMyMaps implements Runnable {
       Log.d(TAG,
           "SendToMyMaps: Prepared feature for upload w/ "
           + splitTrack.getLocations().size() + " points.");
-  
+
       // Transmit tracks via GData feed:
       // -------------------------------
       Log.d(TAG,
@@ -340,7 +347,7 @@ public class SendToMyMaps implements Runnable {
         return false;
       }
     }
-  
+
     locations.clear();
     totalLocationsUploaded += numLocations;
     updateProgress();
@@ -358,7 +365,7 @@ public class SendToMyMaps implements Runnable {
   private ArrayList<Track> prepareLocations(
       Track track, Iterable<Location> locations) {
     ArrayList<Track> splitTracks = new ArrayList<Track>();
-  
+
     // Create segments from each full track:
     Track segment = new Track();
     TripStatistics segmentStats = segment.getStatistics();
@@ -377,11 +384,11 @@ public class SendToMyMaps implements Runnable {
       if (loc.getLatitude() > 90) {
         startNewTrackSegment = true;
       }
-  
+
       if (startNewTrackSegment) {
         // Close up the last segment.
         prepareTrackSegment(segment, splitTracks);
-  
+
         Log.d(TAG,
             "MyTracksSendToMyMaps: Starting new track segment...");
         startNewTrackSegment = false;
@@ -391,7 +398,7 @@ public class SendToMyMaps implements Runnable {
         segment.setDescription(/* track.getDescription() */ "");
         segment.setCategory(track.getCategory());
       }
-  
+
       if (loc.getLatitude() <= 90) {
         segment.addLocation(loc);
         if (segmentStats.getStartTime() < 0) {
@@ -400,9 +407,9 @@ public class SendToMyMaps implements Runnable {
       }
       totalLocationsPrepared++;
     }
-  
+
     prepareTrackSegment(segment, splitTracks);
-  
+
     return splitTracks;
   }
 
@@ -425,13 +432,13 @@ public class SendToMyMaps implements Runnable {
         && segment.getLocations().size() > 0) {
       segmentStats.setStopTime(segment.getLocations().size() - 1);
     }
-  
+
     /*
      * Decimate to 2 meter precision. Mapshop doesn't like too many
      * points:
      */
     LocationUtils.decimate(segment, 2.0);
-  
+
     /* It the track still has > 500 points, split it in pieces: */
     if (segment.getLocations().size() > 500) {
       splitTracks.addAll(LocationUtils.split(segment, 500));

MyTracks/src/com/google/android/apps/mytracks/io/file/TrackWriterFactory.java

@@ -16,10 +16,13 @@
 
 package com.google.android.apps.mytracks.io.file;
 
+import static com.google.android.apps.mytracks.Constants.TAG;
+
 import com.google.android.apps.mytracks.content.MyTracksProviderUtils;
 import com.google.android.apps.mytracks.content.Track;
 
 import android.content.Context;
+import android.util.Log;
 
 /**
  * A factory to produce track writers for any format.
@@ -90,6 +93,11 @@ public class TrackWriterFactory {
       MyTracksProviderUtils providerUtils,
       long trackId, TrackFileFormat format) {
     Track track = providerUtils.getTrack(trackId);
+    if (track == null) {
+      Log.w(TAG, "Trying to create a writer for an invalid track, id=" + trackId);
+      return null;
+    }
+
     return newWriter(context, providerUtils, track, format);
   }
 

MyTracksLib/src/com/google/android/apps/mytracks/content/MyTracksProviderUtilsImpl.java

@@ -1,12 +1,12 @@
 /*
  * Copyright 2008 Google Inc.
- * 
+ *
  * 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
@@ -40,7 +40,7 @@ import java.util.NoSuchElementException;
 public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
 
   private final ContentResolver contentResolver;
-  
+
   private int defaultCursorBatchSize = 2000;
 
   public MyTracksProviderUtilsImpl(ContentResolver contentResolver) {
@@ -199,12 +199,12 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
     public final int idxLatitude;
     public final int idxLongitude;
     public final int idxAltitude;
-    public final int idxTime; 
+    public final int idxTime;
-    public final int idxBearing; 
+    public final int idxBearing;
     public final int idxAccuracy;
     public final int idxSpeed;
-    public final int idxSensor; 
+    public final int idxSensor;
-  
+
     public CachedTrackColumnIndices(Cursor cursor) {
       idxId = cursor.getColumnIndex(TrackPointsColumns._ID);
       idxLatitude = cursor.getColumnIndexOrThrow(TrackPointsColumns.LATITUDE);
@@ -217,11 +217,11 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
       idxSensor = cursor.getColumnIndexOrThrow(TrackPointsColumns.SENSOR);
     }
   }
-  
+
   private void fillLocation(Cursor cursor, CachedTrackColumnIndices columnIndices,
       Location location) {
     location.reset();
-    
+
     if (!cursor.isNull(columnIndices.idxLatitude)) {
       location.setLatitude(1. * cursor.getInt(columnIndices.idxLatitude) / 1E6);
     }
@@ -256,7 +256,7 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
       }
     }
   }
-  
+
   @Override
   public void fillLocation(Cursor cursor, Location location) {
     CachedTrackColumnIndices columnIndicies = new CachedTrackColumnIndices(cursor);
@@ -660,6 +660,10 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
 
   @Override
   public Waypoint getFirstWaypoint(long trackId) {
+    if (trackId <= 0) {
+      return null;
+    }
+
     Cursor cursor = contentResolver.query(
         WaypointsColumns.CONTENT_URI,
         null /*projection*/,
@@ -682,6 +686,10 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
 
   @Override
   public Waypoint getWaypoint(long waypointId) {
+    if (waypointId < 0) {
+      return null;
+    }
+
     Cursor cursor = contentResolver.query(
         WaypointsColumns.CONTENT_URI,
         null /*projection*/,
@@ -704,6 +712,10 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
 
   @Override
   public long getLastLocationId(long trackId) {
+    if (trackId < 0) {
+      return -1;
+    }
+
     final String[] projection = {"_id"};
     Cursor cursor = contentResolver.query(
         TrackPointsColumns.CONTENT_URI,
@@ -728,6 +740,10 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
 
   @Override
   public long getFirstWaypointId(long trackId) {
+    if (trackId < 0) {
+      return -1;
+    }
+
     final String[] projection = {"_id"};
     Cursor cursor = contentResolver.query(
         WaypointsColumns.CONTENT_URI,
@@ -752,6 +768,10 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
 
   @Override
   public long getLastWaypointId(long trackId) {
+    if (trackId < 0) {
+      return -1;
+    }
+
     final String[] projection = {"_id"};
     Cursor cursor = contentResolver.query(
         WaypointsColumns.CONTENT_URI,
@@ -815,6 +835,10 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
 
   @Override
   public Location getLocation(long id) {
+    if (id < 0) {
+      return null;
+    }
+
     String selection = TrackPointsColumns._ID + "=" + id;
     return findLocationBy(selection);
   }
@@ -822,7 +846,11 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
   @Override
   public Cursor getLocationsCursor(long trackId, long minTrackPointId,
       int maxLocations, boolean descending) {
-    String selection; 
+    if (trackId < 0 || maxLocations < 1) {
+      return null;
+    }
+
+    String selection;
     if (minTrackPointId >= 0) {
       selection = String.format("%s=%d AND %s%s%d",
           TrackPointsColumns.TRACKID, trackId, TrackPointsColumns._ID,
@@ -842,6 +870,10 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
   @Override
   public Cursor getWaypointsCursor(long trackId, long minWaypointId,
       int maxWaypoints) {
+    if (trackId < 0 || maxWaypoints < 1) {
+      return null;
+    }
+
     String selection;
     if (minWaypointId > 0) {
       selection = String.format("%s=%d AND %s>=%d",
@@ -863,6 +895,10 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
 
   @Override
   public Track getTrack(long id) {
+    if (id < 0) {
+      return null;
+    }
+
     String select = TracksColumns._ID + "=" + id;
     return findTrackBy(select);
   }
@@ -929,6 +965,10 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
 
   @Override
   public boolean trackExists(long id) {
+    if (id < 0) {
+      return false;
+    }
+
     Cursor cursor = null;
     try {
       final String[] projection = { TracksColumns._ID };
@@ -967,7 +1007,7 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
       private Cursor cursor = getCursor(startTrackPointId);
       private final CachedTrackColumnIndices columnIndices = cursor != null ?
           new CachedTrackColumnIndices(cursor) : null;
-          
+
       private Cursor getCursor(long trackPointId) {
         return getLocationsCursor(trackId, trackPointId, defaultCursorBatchSize, descending);
       }
@@ -979,7 +1019,7 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
         cursor = getCursor(pointId);
         return cursor != null;
       }
-        
+
       @Override
       public long getLocationId() {
         return lastTrackPointId;
@@ -999,7 +1039,7 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
           return cursor.getCount() == defaultCursorBatchSize &&
               advanceCursorToNextBatch() && !cursor.isAfterLast();
         }
-        
+
         return true;
       }
 
@@ -1009,11 +1049,11 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
             !(cursor.moveToNext() || advanceCursorToNextBatch() || cursor.moveToNext())) {
           throw new NoSuchElementException();
         }
-        
+
         lastTrackPointId = cursor.getLong(columnIndices.idxId);
         Location location = locationFactory.createLocation();
         fillLocation(cursor, columnIndices, location);
-        
+
         return location;
       }
 
@@ -1031,7 +1071,7 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
       }
     };
   }
-  
+
   // @VisibleForTesting
   void setDefaultCursorBatchSize(int defaultCursorBatchSize) {
     this.defaultCursorBatchSize = defaultCursorBatchSize;