Obtain paths to file directories on a worker thread

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/Mapbox.java

@@ -11,6 +11,9 @@
 import com.mapbox.mapboxsdk.exceptions.MapboxConfigurationException;
 import com.mapbox.mapboxsdk.maps.Telemetry;
 import com.mapbox.mapboxsdk.net.ConnectivityReceiver;
+import com.mapbox.mapboxsdk.storage.FileSource;
+import com.mapbox.mapboxsdk.utils.ThreadUtils;
+
 import timber.log.Timber;
 
 /**
@@ -42,8 +45,10 @@ public final class Mapbox {
    */
   @UiThread
   public static synchronized Mapbox getInstance(@NonNull Context context, @Nullable String accessToken) {
+    ThreadUtils.checkThread("Mapbox");
     if (INSTANCE == null) {
       Context appContext = context.getApplicationContext();
+      FileSource.initializeFileDirsPaths(appContext);
       INSTANCE = new Mapbox(appContext, accessToken);
       if (isAccessTokenValid(accessToken)) {
         initializeTelemetry();

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/renderer/MapRenderer.java

@@ -28,7 +28,7 @@ public abstract class MapRenderer implements MapRendererScheduler {
   public MapRenderer(Context context, String localIdeographFontFamily) {
     FileSource fileSource = FileSource.getInstance(context);
     float pixelRatio = context.getResources().getDisplayMetrics().density;
-    String programCacheDir = context.getCacheDir().getAbsolutePath();
+    String programCacheDir = FileSource.getInternalCachePath(context);
 
     // Initialise native peer
     nativeInitialize(this, fileSource, pixelRatio, programCacheDir, localIdeographFontFamily);

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/offline/OfflineManager.java

@@ -109,7 +109,7 @@ private void deleteAmbientDatabase(final Context context) {
       @Override
       public void run() {
         try {
-          String path = context.getCacheDir().getAbsolutePath() + File.separator + "mbgl-cache.db";
+          String path = FileSource.getInternalCachePath(context) + File.separator + "mbgl-cache.db";
           File file = new File(path);
           if (file.exists()) {
             file.delete();

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/snapshotter/MapSnapshotter.java

@@ -217,7 +217,7 @@ public MapSnapshotter(@NonNull Context context, @NonNull Options options) {
     checkThread();
     this.context = context.getApplicationContext();
     FileSource fileSource = FileSource.getInstance(context);
-    String programCacheDir = context.getCacheDir().getAbsolutePath();
+    String programCacheDir = FileSource.getInternalCachePath(context);
 
     nativeInitialize(this, fileSource, options.pixelRatio, options.width,
       options.height, options.styleUrl, options.styleJson, options.region, options.cameraPosition,

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/storage/FileSource.java

@@ -4,13 +4,18 @@
 import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageManager;
 import android.content.res.AssetManager;
+import android.os.AsyncTask;
 import android.os.Environment;
 import android.support.annotation.Keep;
 import android.support.annotation.NonNull;
 import android.support.annotation.UiThread;
 
 import com.mapbox.mapboxsdk.Mapbox;
 import com.mapbox.mapboxsdk.constants.MapboxConstants;
+import com.mapbox.mapboxsdk.utils.ThreadUtils;
+
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
 
 import timber.log.Timber;
 
@@ -20,6 +25,11 @@
  */
 public class FileSource {
 
+  private static String resourcesCachePath;
+  private static String internalCachePath;
+  private static final Lock resourcesCachePathLoaderLock = new ReentrantLock();
+  private static final Lock internalCachePathLoaderLock = new ReentrantLock();
+
   /**
    * This callback allows implementors to transform URLs before they are requested
    * from the internet. This can be used add or remove custom parameters, or reroute
@@ -51,19 +61,20 @@ public interface ResourceTransformCallback {
   @UiThread
   public static synchronized FileSource getInstance(Context context) {
     if (INSTANCE == null) {
-      String cachePath = getCachePath(context);
-      INSTANCE = new FileSource(cachePath, context.getResources().getAssets());
+      INSTANCE = new FileSource(getResourcesCachePath(context), context.getResources().getAssets());
     }
 
     return INSTANCE;
   }
 
   /**
-   * Get the cache path for a context.
+   * Get files directory path for a context.
    *
-   * @param context the context to derive the cache path from
-   * @return the cache path
+   * @param context the context to derive the files directory path from
+   * @return the files directory path
+   * @deprecated Use {@link #getResourcesCachePath(Context)} instead.
    */
+  @Deprecated
   public static String getCachePath(Context context) {
     // Default value
     boolean setStorageExternal = MapboxConstants.DEFAULT_SET_STORAGE_EXTERNAL;
@@ -122,6 +133,89 @@ public static boolean isExternalStorageReadable() {
     return false;
   }
 
+  /**
+   * Initializes file directories paths.
+   *
+   * @param context the context to derive paths from
+   */
+  @UiThread
+  public static void initializeFileDirsPaths(Context context) {
+    ThreadUtils.checkThread("FileSource");
+    lockPathLoaders();
+    if (resourcesCachePath == null || internalCachePath == null) {
+      new FileDirsPathsTask().execute(context);
+    }
+  }
+
+  private static class FileDirsPathsTask extends AsyncTask<Context, Void, String[]> {
+
+    @Override
+    protected void onCancelled() {
+      unlockPathLoaders();
+    }
+
+    @Override
+    protected String[] doInBackground(Context... contexts) {
+      return new String[] {
+        getCachePath(contexts[0]),
+        contexts[0].getCacheDir().getAbsolutePath()
+      };
+    }
+
+    @Override
+    protected void onPostExecute(String[] paths) {
+      resourcesCachePath = paths[0];
+      internalCachePath = paths[1];
+      unlockPathLoaders();
+    }
+  }
+
+  /**
+   * Get files directory path for a context.
+   *
+   * @param context the context to derive the files directory path from
+   * @return the files directory path
+   */
+  public static String getResourcesCachePath(Context context) {
+    resourcesCachePathLoaderLock.lock();
+    try {
+      if (resourcesCachePath == null) {
+        resourcesCachePath = getCachePath(context);
+      }
+      return resourcesCachePath;
+    } finally {
+      resourcesCachePathLoaderLock.unlock();
+    }
+  }
+
+  /**
+   * Get internal cache path for a context.
+   *
+   * @param context the context to derive the internal cache path from
+   * @return the internal cache path
+   */
+  public static String getInternalCachePath(Context context) {
+    internalCachePathLoaderLock.lock();
+    try {
+      if (internalCachePath == null) {
+        internalCachePath = context.getCacheDir().getAbsolutePath();
+      }
+      return internalCachePath;
+    } finally {
+      internalCachePathLoaderLock.unlock();
+    }
+  }
+
+  private static void lockPathLoaders() {
+    internalCachePathLoaderLock.lock();
+    resourcesCachePathLoaderLock.lock();
+  }
+
+  private static void unlockPathLoaders() {
+    resourcesCachePathLoaderLock.unlock();
+    internalCachePathLoaderLock.unlock();
+  }
+
   @Keep
   private long nativePtr;