content: /*
   * Copyright (C) 2014 Hari Krishna Dulipudi
   * Copyright (C) 2013 The Android Open Source Project
   *
   * 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 License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package dev.dworks.apps.anexplorer.loader;
  
  import android.annotation.TargetApi;
  import android.content.Context;
  import android.database.ContentObserver;
  import android.os.Build;
  import android.os.CancellationSignal;
  import android.os.OperationCanceledException;
  
  import java.io.Closeable;
  
  import dev.dworks.apps.anexplorer.misc.AsyncTaskLoader;
  
  /**
   * Loader that derives its data from a Uri. Watches for {@link ContentObserver}
   * changes while started, manages {@link CancellationSignal}, and caches
   * returned results.
   */
  public abstract class UriDerivativeLoader<P, R> extends AsyncTaskLoader<R> {
      final ForceLoadContentObserver mObserver;
  
      private final P mParam;
  
      private R mResult;
      private CancellationSignal mCancellationSignal;
  
  	private boolean mCancelled;
  
      @Override
      public final R loadInBackground() {
          synchronized (this) {
              if (isLoadInBackgroundCanceled2()) {
                  throw new OperationCanceledException();
              }
              mCancellationSignal = new CancellationSignal();
          }
          try {
              return loadInBackground(mParam, mCancellationSignal);
          } finally {
              synchronized (this) {
                  mCancellationSignal = null;
              }
          }
      }
  
      private boolean isLoadInBackgroundCanceled2() {
  		return mCancelled;
  	}
  
  	public abstract R loadInBackground(P param, CancellationSignal signal);
  
      public void cancelLoadInBackground2() {
  
          synchronized (this) {
              if (mCancellationSignal != null) {
                  mCancellationSignal.cancel();
              }
          }
      }
  
      @Override
      public void deliverResult(R result) {
          if (isReset()) {
              closeQuietly(result);
              return;
          }
          R oldResult = mResult;
          mResult = result;
  
          if (isStarted()) {
              super.deliverResult(result);
          }
  
          if (oldResult != null && oldResult != result) {
              closeQuietly(oldResult);
          }
      }
  
      public UriDerivativeLoader(Context context, P param) {
          super(context);
          mObserver = new ForceLoadContentObserver();
          mParam = param;
      }
  
      @Override
      protected void onStartLoading() {
          if (mResult != null) {
              deliverResult(mResult);
          }
          if (takeContentChanged() || mResult == null) {
              forceLoad();
          }
      }
  
      @Override
      protected void onStopLoading() {
          cancelLoad();
      }
  
      @Override
      public void onCanceled(R result) {
      	mCancelled = true;
      	cancelLoadInBackground2();
          closeQuietly(result);
      }
  
      @Override
      protected void onReset() {
          super.onReset();
  
          // Ensure the loader is stopped
          onStopLoading();
  
          closeQuietly(mResult);
          mResult = null;
  
          getContext().getContentResolver().unregisterContentObserver(mObserver);
      }
  
      @TargetApi(Build.VERSION_CODES.KITKAT)
      private void closeQuietly(R result) {
          if (result instanceof Closeable) {
              try {
                  ((Closeable) result).close();
              } catch (RuntimeException rethrown) {
                  throw rethrown;
              } catch (Exception ignored) {
              }
          }
          else if (result instanceof AutoCloseable) {
              try {
                  ((AutoCloseable) result).close();
              } catch (RuntimeException rethrown) {
                  throw rethrown;
              } catch (Exception ignored) {
              }
          }
      }
  }