content: /**
   * Copyright 2010-present Facebook.
   *
   * 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 com.facebook.internal;
  
  import android.content.Context;
  import android.util.Log;
  import com.facebook.LoggingBehavior;
  
  import java.io.BufferedInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.net.HttpURLConnection;
  import java.net.URI;
  import java.net.URISyntaxException;
  import java.net.URL;
  
  class ImageResponseCache {
      static final String TAG = ImageResponseCache.class.getSimpleName();
  
      private volatile static FileLruCache imageCache;
  
      synchronized static FileLruCache getCache(Context context) throws IOException{
          if (imageCache == null) {
              imageCache = new FileLruCache(context.getApplicationContext(), TAG, new FileLruCache.Limits());
          }
          return imageCache;
      }
  
      // Get stream from cache, or return null if the image is not cached.
      // Does not throw if there was an error.
      static InputStream getCachedImageStream(URI url, Context context) {
          InputStream imageStream = null;
          if (url != null) {
              if (isCDNURL(url)) {
                  try {
                      FileLruCache cache = getCache(context);
                      imageStream = cache.get(url.toString());
                  } catch (IOException e) {
                      Logger.log(LoggingBehavior.CACHE, Log.WARN, TAG, e.toString());
                  }
              }
          }
  
          return imageStream;
      }
  
      static InputStream interceptAndCacheImageStream(Context context, HttpURLConnection connection) throws IOException {
          InputStream stream = null;
          if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
              URL url = connection.getURL();
              stream = connection.getInputStream(); // Default stream in case caching fails
              try {
                  if (isCDNURL(url.toURI())) {
                      FileLruCache cache = getCache(context);
  
                      // Wrap stream with a caching stream
                      stream = cache.interceptAndPut(
                              url.toString(),
                              new BufferedHttpInputStream(stream, connection));
                  }
              } catch (IOException e) {
                  // Caching is best effort
              } catch (URISyntaxException e) {
              // Caching is best effort
              }
          }
          return stream;
      }
  
     private static boolean isCDNURL(URI url) {
          if (url != null) {
              String uriHost = url.getHost();
  
              if (uriHost.endsWith("fbcdn.net")) {
                  return true;
              }
  
              if (uriHost.startsWith("fbcdn") && uriHost.endsWith("akamaihd.net")) {
                  return true;
              }
          }
  
          return false;
      }
  
      static void clearCache(Context context) {
          try {
              getCache(context).clearCache();
          } catch (IOException e) {
              Logger.log(LoggingBehavior.CACHE, Log.WARN, TAG, "clearCache failed " + e.getMessage());
          }
      }
  
      private static class BufferedHttpInputStream extends BufferedInputStream {
          HttpURLConnection connection;
          BufferedHttpInputStream(InputStream stream, HttpURLConnection connection) {
              super(stream, Utility.DEFAULT_STREAM_BUFFER_SIZE);
              this.connection = connection;
          }
  
          @Override
          public void close() throws IOException {
              super.close();
              Utility.disconnectQuietly(connection);
          }
      }
  }
  
  