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.content.res.Resources;
  import android.net.Uri;
  import android.text.TextUtils;
  import androidx.annotation.Nullable;
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.PlaybackException;
  import com.google.android.exoplayer2.util.Assertions;
  import java.io.EOFException;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.nio.channels.FileChannel;
  
  /**
   * A {@link DataSource} for reading a raw resource inside the APK.
   *
   * <p>URIs supported by this source are of one of the forms:
   *
   * <ul>
   *   <li>{@code rawresource:///id}, where {@code id} is the integer identifier of a raw resource.
   *   <li>{@code android.resource:///id}, where {@code id} is the integer identifier of a raw
   *       resource.
   *   <li>{@code android.resource://[package]/[type/]name}, where {@code package} is the name of the
   *       package in which the resource is located, {@code type} is the resource type and {@code
   *       name} is the resource name. The package and the type are optional. Their default value is
   *       the package of this application and "raw", respectively. Using the two other forms is more
   *       efficient.
   * </ul>
   *
   * <p>{@link #buildRawResourceUri(int)} can be used to build supported {@link Uri}s.
   */
  public final class RawResourceDataSource extends BaseDataSource {
  
    /** Thrown when an {@link IOException} is encountered reading from a raw resource. */
    public static class RawResourceDataSourceException extends DataSourceException {
      /**
       * @deprecated Use {@link #RawResourceDataSourceException(String, Throwable, int)}.
       */
      @Deprecated
      public RawResourceDataSourceException(String message) {
        super(message, /* cause= */ null, PlaybackException.ERROR_CODE_IO_UNSPECIFIED);
      }
  
      /**
       * @deprecated Use {@link #RawResourceDataSourceException(String, Throwable, int)}.
       */
      @Deprecated
      public RawResourceDataSourceException(Throwable cause) {
        super(cause, PlaybackException.ERROR_CODE_IO_UNSPECIFIED);
      }
  
      /** Creates a new instance. */
      public RawResourceDataSourceException(
          @Nullable String message,
          @Nullable Throwable cause,
          @PlaybackException.ErrorCode int errorCode) {
        super(message, cause, errorCode);
      }
    }
  
    /**
     * Builds a {@link Uri} for the specified raw resource identifier.
     *
     * @param rawResourceId A raw resource identifier (i.e. a constant defined in {@code R.raw}).
     * @return The corresponding {@link Uri}.
     */
    public static Uri buildRawResourceUri(int rawResourceId) {
      return Uri.parse(RAW_RESOURCE_SCHEME + ":///" + rawResourceId);
    }
  
    /** The scheme part of a raw resource URI. */
    public static final String RAW_RESOURCE_SCHEME = "rawresource";
  
    private final Resources resources;
    private final String packageName;
  
    @Nullable private Uri uri;
    @Nullable private AssetFileDescriptor assetFileDescriptor;
    @Nullable private InputStream inputStream;
    private long bytesRemaining;
    private boolean opened;
  
    /**
     * @param context A context.
     */
    public RawResourceDataSource(Context context) {
      super(/* isNetwork= */ false);
      this.resources = context.getResources();
      this.packageName = context.getPackageName();
    }
  
    @Override
    public long open(DataSpec dataSpec) throws RawResourceDataSourceException {
      Uri uri = dataSpec.uri;
      this.uri = uri;
  
      int resourceId;
      if (TextUtils.equals(RAW_RESOURCE_SCHEME, uri.getScheme())
          || (TextUtils.equals(ContentResolver.SCHEME_ANDROID_RESOURCE, uri.getScheme())
              && uri.getPathSegments().size() == 1
              && Assertions.checkNotNull(uri.getLastPathSegment()).matches("\\d+"))) {
        try {
          resourceId = Integer.parseInt(Assertions.checkNotNull(uri.getLastPathSegment()));
        } catch (NumberFormatException e) {
          throw new RawResourceDataSourceException(
              "Resource identifier must be an integer.",
              /* cause= */ null,
              PlaybackException.ERROR_CODE_FAILED_RUNTIME_CHECK);
        }
      } else if (TextUtils.equals(ContentResolver.SCHEME_ANDROID_RESOURCE, uri.getScheme())) {
        String path = Assertions.checkNotNull(uri.getPath());
        if (path.startsWith("/")) {
          path = path.substring(1);
        }
        @Nullable String host = uri.getHost();
        String resourceName = (TextUtils.isEmpty(host) ? "" : (host + ":")) + path;
        resourceId =
            resources.getIdentifier(
                resourceName, /* defType= */ "raw", /* defPackage= */ packageName);
        if (resourceId == 0) {
          throw new RawResourceDataSourceException(
              "Resource not found.",
              /* cause= */ null,
              PlaybackException.ERROR_CODE_IO_FILE_NOT_FOUND);
        }
      } else {
        throw new RawResourceDataSourceException(
            "URI must either use scheme "
                + RAW_RESOURCE_SCHEME
                + " or "
                + ContentResolver.SCHEME_ANDROID_RESOURCE,
            /* cause= */ null,
            PlaybackException.ERROR_CODE_FAILED_RUNTIME_CHECK);
      }
  
      transferInitializing(dataSpec);
  
      AssetFileDescriptor assetFileDescriptor;
      try {
        assetFileDescriptor = resources.openRawResourceFd(resourceId);
      } catch (Resources.NotFoundException e) {
        throw new RawResourceDataSourceException(
            /* message= */ null, e, PlaybackException.ERROR_CODE_IO_FILE_NOT_FOUND);
      }
  
      this.assetFileDescriptor = assetFileDescriptor;
      if (assetFileDescriptor == null) {
        throw new RawResourceDataSourceException(
            "Resource is compressed: " + uri,
            /* cause= */ null,
            PlaybackException.ERROR_CODE_IO_UNSPECIFIED);
      }
  
      long assetFileDescriptorLength = assetFileDescriptor.getLength();
      FileInputStream inputStream = new FileInputStream(assetFileDescriptor.getFileDescriptor());
      this.inputStream = inputStream;
  
      try {
        // We can't rely only on the "skipped < dataSpec.position" check below to detect whether the
        // position is beyond the end of the resource being read. This is because the file will
        // typically contain multiple resources, and there's nothing to prevent InputStream.skip()
        // from succeeding by skipping into the data of the next resource. Hence we also need to check
        // against the resource length explicitly, which is guaranteed to be set unless the resource
        // extends to the end of the file.
        if (assetFileDescriptorLength != AssetFileDescriptor.UNKNOWN_LENGTH
            && dataSpec.position > assetFileDescriptorLength) {
          throw new RawResourceDataSourceException(
              /* message= */ null,
              /* 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 RawResourceDataSourceException(
              /* message= */ null,
              /* 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();
          if (channel.size() == 0) {
            bytesRemaining = C.LENGTH_UNSET;
          } else {
            bytesRemaining = channel.size() - channel.position();
            if (bytesRemaining < 0) {
              // The skip above was satisfied in full, but skipped beyond the end of the file.
              throw new RawResourceDataSourceException(
                  /* message= */ null,
                  /* cause= */ null,
                  PlaybackException.ERROR_CODE_IO_READ_POSITION_OUT_OF_RANGE);
            }
          }
        } else {
          bytesRemaining = assetFileDescriptorLength - skipped;
          if (bytesRemaining < 0) {
            throw new DataSourceException(PlaybackException.ERROR_CODE_IO_READ_POSITION_OUT_OF_RANGE);
          }
        }
      } catch (RawResourceDataSourceException e) {
        throw e;
      } catch (IOException e) {
        throw new RawResourceDataSourceException(
            /* message= */ null, e, 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 RawResourceDataSourceException {
      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 RawResourceDataSourceException(
            /* message= */ null, e, PlaybackException.ERROR_CODE_IO_UNSPECIFIED);
      }
  
      if (bytesRead == -1) {
        if (bytesRemaining != C.LENGTH_UNSET) {
          // End of stream reached having not read sufficient data.
          throw new RawResourceDataSourceException(
              "End of stream reached having not read sufficient data.",
              new EOFException(),
              PlaybackException.ERROR_CODE_IO_UNSPECIFIED);
        }
        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 RawResourceDataSourceException {
      uri = null;
      try {
        if (inputStream != null) {
          inputStream.close();
        }
      } catch (IOException e) {
        throw new RawResourceDataSourceException(
            /* message= */ null, e, PlaybackException.ERROR_CODE_IO_UNSPECIFIED);
      } finally {
        inputStream = null;
        try {
          if (assetFileDescriptor != null) {
            assetFileDescriptor.close();
          }
        } catch (IOException e) {
          throw new RawResourceDataSourceException(
              /* message= */ null, e, PlaybackException.ERROR_CODE_IO_UNSPECIFIED);
        } finally {
          assetFileDescriptor = null;
          if (opened) {
            opened = false;
            transferEnded();
          }
        }
      }
    }
  }
  