content: /*
   * Copyright 2019 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 android.media;
  
  import android.os.ParcelFileDescriptor;
  import android.system.ErrnoException;
  import android.system.Os;
  import android.system.OsConstants;
  import android.util.Log;
  
  import java.io.FileDescriptor;
  import java.io.IOException;
  
  /**
   * A DataSourceCallback that is backed by a ParcelFileDescriptor.
   */
  class ProxyDataSourceCallback extends DataSourceCallback {
      private static final String TAG = "TestDataSourceCallback";
  
      ParcelFileDescriptor mPFD;
      FileDescriptor mFD;
  
      ProxyDataSourceCallback(ParcelFileDescriptor pfd) throws IOException {
          mPFD = pfd.dup();
          mFD = mPFD.getFileDescriptor();
      }
  
      @Override
      public synchronized int readAt(long position, byte[] buffer, int offset, int size)
              throws IOException {
          try {
              Os.lseek(mFD, position, OsConstants.SEEK_SET);
              int ret = Os.read(mFD, buffer, offset, size);
              return (ret == 0) ? END_OF_STREAM : ret;
          } catch (ErrnoException e) {
              throw new IOException(e);
          }
      }
  
      @Override
      public synchronized long getSize() throws IOException {
          return mPFD.getStatSize();
      }
  
      @Override
      public synchronized void close() {
          try {
              mPFD.close();
          } catch (IOException e) {
              Log.e(TAG, "Failed to close the PFD.", e);
          }
      }
  }
  
  