content: /*
   * Copyright 2018 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.annotation.NonNull;
  import android.os.ParcelFileDescriptor;
  import android.util.Log;
  
  import java.io.IOException;
  
  /**
   * Structure of data source descriptor for sources using file descriptor.
   *
   * Used by {@link MediaPlayer2#setDataSource}, {@link MediaPlayer2#setNextDataSource} and
   * {@link MediaPlayer2#setNextDataSources} to set data source for playback.
   *
   * <p>Users should use {@link Builder} to create {@link FileDataSourceDesc}.
   * @hide
   */
  public class FileDataSourceDesc extends DataSourceDesc {
      private static final String TAG = "FileDataSourceDesc";
  
      /**
       * Used when the length of file descriptor is unknown.
       *
       * @see #getLength()
       */
      public static final long FD_LENGTH_UNKNOWN = LONG_MAX;
  
      private ParcelFileDescriptor mPFD;
      private long mOffset = 0;
      private long mLength = FD_LENGTH_UNKNOWN;
      private int mCount = 0;
      private boolean mClosed = false;
  
      FileDataSourceDesc(String mediaId, long startPositionMs, long endPositionMs,
              ParcelFileDescriptor pfd, long offset, long length) {
          super(mediaId, startPositionMs, endPositionMs);
          mPFD = pfd;
          mOffset = offset;
          mLength = length;
      }
  
      /**
       * Releases the resources held by this {@code FileDataSourceDesc} object.
       */
      @Override
      void close() {
          super.close();
          decCount();
      }
  
      /**
       * Decrements usage count by {@link MediaPlayer2}.
       * If this is the last usage, also releases the file descriptor held by this
       * {@code FileDataSourceDesc} object.
       */
      void decCount() {
          synchronized (this) {
              --mCount;
              if (mCount > 0) {
                  return;
              }
  
              try {
                  mPFD.close();
                  mClosed = true;
              } catch (IOException e) {
                  Log.e(TAG, "failed to close pfd: " + e);
              }
          }
      }
  
      /**
       * Increments usage count by {@link MediaPlayer2} if PFD has not been closed.
       */
      void incCount() {
          synchronized (this) {
              if (!mClosed) {
                  ++mCount;
              }
          }
      }
  
      /**
       * Return the status of underline ParcelFileDescriptor
       * @return true if underline ParcelFileDescriptor is closed, false otherwise.
       */
      boolean isPFDClosed() {
          synchronized (this) {
              return mClosed;
          }
      }
  
      /**
       * Return the ParcelFileDescriptor of this data source.
       * @return the ParcelFileDescriptor of this data source
       */
      public @NonNull ParcelFileDescriptor getParcelFileDescriptor() {
          return mPFD;
      }
  
      /**
       * Return the offset associated with the ParcelFileDescriptor of this data source.
       * It's meaningful only when it has been set by the {@link Builder}.
       * @return the offset associated with the ParcelFileDescriptor of this data source
       */
      public long getOffset() {
          return mOffset;
      }
  
      /**
       * Return the content length associated with the ParcelFileDescriptor of this data source.
       * {@link #FD_LENGTH_UNKNOWN} means same as the length of source content.
       * @return the content length associated with the ParcelFileDescriptor of this data source
       */
      public long getLength() {
          return mLength;
      }
  }
  