content: /*
   * Copyright (C) 2016 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 com.google.android.exoplayer2.upstream;
  
  import static com.google.android.exoplayer2.util.Util.castNonNull;
  import static java.lang.Math.min;
  
  import android.content.ContentResolver;
  import android.content.Context;
  import android.content.res.AssetFileDescriptor;
  import android.net.Uri;
  import android.os.Bundle;
  import android.provider.MediaStore;
  import androidx.annotation.Nullable;
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.PlaybackException;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.nio.channels.FileChannel;
  
  /** A {@link DataSource} for reading from a content URI. */
  public final class ContentDataSource extends BaseDataSource {
  
    /** Thrown when an {@link IOException} is encountered reading from a content URI. */
    public static class ContentDataSourceException extends DataSourceException {
  
      /**
       * @deprecated Use {@link #ContentDataSourceException(IOException, int)}.
       */
      @Deprecated
      public ContentDataSourceException(IOException cause) {
        this(cause, PlaybackException.ERROR_CODE_IO_UNSPECIFIED);
      }
  
      /** Creates a new instance. */
      public ContentDataSourceException(
          @Nullable IOException cause, @PlaybackException.ErrorCode int errorCode) {
        super(cause, errorCode);
      }
    }
  
    private final ContentResolver resolver;
  
    @Nullable private Uri uri;
    @Nullable private AssetFileDescriptor assetFileDescriptor;
    @Nullable private FileInputStream inputStream;
    private long bytesRemaining;
    private boolean opened;
  
    /**
     * @param context A context.
     */
    public ContentDataSource(Context context) {
      super(/* isNetwork= */ false);
      this.resolver = context.getContentResolver();
    }
  
    @Override
    @SuppressWarnings("InlinedApi") // We are inlining EXTRA_ACCEPT_ORIGINAL_MEDIA_FORMAT.
    public long open(DataSpec dataSpec) throws ContentDataSourceException {
      try {
        Uri uri = dataSpec.uri;
        this.uri = uri;
  
        transferInitializing(dataSpec);
  
        AssetFileDescriptor assetFileDescriptor;
        if ("content".equals(dataSpec.uri.getScheme())) {
          Bundle providerOptions = new Bundle();
          // We don't want compatible media transcoding.
          providerOptions.putBoolean(MediaStore.EXTRA_ACCEPT_ORIGINAL_MEDIA_FORMAT, true);
          assetFileDescriptor =
              resolver.openTypedAssetFileDescriptor(uri, /* mimeType= */ "*/*", providerOptions);
        } else {
          // This path supports file URIs, although support may be removed in the future. See
          // [Internal ref: b/195384732].
          assetFileDescriptor = resolver.openAssetFileDescriptor(uri, "r");
        }
        this.assetFileDescriptor = assetFileDescriptor;
        if (assetFileDescriptor == null) {
          // assetFileDescriptor may be null if the provider recently crashed.
          throw new ContentDataSourceException(
              new IOException("Could not open file descriptor for: " + uri),
              PlaybackException.ERROR_CODE_IO_UNSPECIFIED);
        }
  
        long assetFileDescriptorLength = assetFileDescriptor.getLength();
        FileInputStream inputStream = new FileInputStream(assetFileDescriptor.getFileDescriptor());
        this.inputStream = inputStream;
  
        // We can't rely only on the "skipped < dataSpec.position" check below to detect whether the
        // position is beyond the end of the asset being read. This is because the file may contain
        // multiple assets, and there's nothing to prevent InputStream.skip() from succeeding by
        // skipping into the data of the next asset. Hence we also need to check against the asset
        // length explicitly, which is guaranteed to be set unless the asset extends to the end of the
        // file.
        if (assetFileDescriptorLength != AssetFileDescriptor.UNKNOWN_LENGTH
            && dataSpec.position > assetFileDescriptorLength) {
          throw new ContentDataSourceException(
              /* cause= */ null, PlaybackException.ERROR_CODE_IO_READ_POSITION_OUT_OF_RANGE);
        }
        long assetFileDescriptorOffset = assetFileDescriptor.getStartOffset();
        long skipped =
            inputStream.skip(assetFileDescriptorOffset + dataSpec.position)
                - assetFileDescriptorOffset;
        if (skipped != dataSpec.position) {
          // We expect the skip to be satisfied in full. If it isn't then we're probably trying to
          // read beyond the end of the last resource in the file.
          throw new ContentDataSourceException(
              /* cause= */ null, PlaybackException.ERROR_CODE_IO_READ_POSITION_OUT_OF_RANGE);
        }
        if (assetFileDescriptorLength == AssetFileDescriptor.UNKNOWN_LENGTH) {
          // The asset must extend to the end of the file. We can try and resolve the length with
          // FileInputStream.getChannel().size().
          FileChannel channel = inputStream.getChannel();
          long channelSize = channel.size();
          if (channelSize == 0) {
            bytesRemaining = C.LENGTH_UNSET;
          } else {
            bytesRemaining = channelSize - channel.position();
            if (bytesRemaining < 0) {
              // The skip above was satisfied in full, but skipped beyond the end of the file.
              throw new ContentDataSourceException(
                  /* cause= */ null, PlaybackException.ERROR_CODE_IO_READ_POSITION_OUT_OF_RANGE);
            }
          }
        } else {
          bytesRemaining = assetFileDescriptorLength - skipped;
          if (bytesRemaining < 0) {
            throw new ContentDataSourceException(
                /* cause= */ null, PlaybackException.ERROR_CODE_IO_READ_POSITION_OUT_OF_RANGE);
          }
        }
      } catch (ContentDataSourceException e) {
        throw e;
      } catch (IOException e) {
        throw new ContentDataSourceException(
            e,
            e instanceof FileNotFoundException
                ? PlaybackException.ERROR_CODE_IO_FILE_NOT_FOUND
                : PlaybackException.ERROR_CODE_IO_UNSPECIFIED);
      }
  
      if (dataSpec.length != C.LENGTH_UNSET) {
        bytesRemaining =
            bytesRemaining == C.LENGTH_UNSET ? dataSpec.length : min(bytesRemaining, dataSpec.length);
      }
      opened = true;
      transferStarted(dataSpec);
      return dataSpec.length != C.LENGTH_UNSET ? dataSpec.length : bytesRemaining;
    }
  
    @Override
    public int read(byte[] buffer, int offset, int length) throws ContentDataSourceException {
      if (length == 0) {
        return 0;
      } else if (bytesRemaining == 0) {
        return C.RESULT_END_OF_INPUT;
      }
  
      int bytesRead;
      try {
        int bytesToRead =
            bytesRemaining == C.LENGTH_UNSET ? length : (int) min(bytesRemaining, length);
        bytesRead = castNonNull(inputStream).read(buffer, offset, bytesToRead);
      } catch (IOException e) {
        throw new ContentDataSourceException(e, PlaybackException.ERROR_CODE_IO_UNSPECIFIED);
      }
  
      if (bytesRead == -1) {
        return C.RESULT_END_OF_INPUT;
      }
      if (bytesRemaining != C.LENGTH_UNSET) {
        bytesRemaining -= bytesRead;
      }
      bytesTransferred(bytesRead);
      return bytesRead;
    }
  
    @Override
    @Nullable
    public Uri getUri() {
      return uri;
    }
  
    @SuppressWarnings("Finally")
    @Override
    public void close() throws ContentDataSourceException {
      uri = null;
      try {
        if (inputStream != null) {
          inputStream.close();
        }
      } catch (IOException e) {
        throw new ContentDataSourceException(e, PlaybackException.ERROR_CODE_IO_UNSPECIFIED);
      } finally {
        inputStream = null;
        try {
          if (assetFileDescriptor != null) {
            assetFileDescriptor.close();
          }
        } catch (IOException e) {
          throw new ContentDataSourceException(e, PlaybackException.ERROR_CODE_IO_UNSPECIFIED);
        } finally {
          assetFileDescriptor = null;
          if (opened) {
            opened = false;
            transferEnded();
          }
        }
      }
    }
  }
  