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/*
* 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 org.mozilla.thirdparty.com.google.android.exoplayer2.upstream;
import static org.mozilla.thirdparty.com.google.android.exoplayer2.util.Util.castNonNull;
import android.content.Context;
import android.content.res.AssetManager;
import android.net.Uri;
import androidx.annotation.Nullable;
import org.mozilla.thirdparty.com.google.android.exoplayer2.C;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Assertions;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
/** A {@link DataSource} for reading from a local asset. */
public final class AssetDataSource extends BaseDataSource {
/**
* Thrown when an {@link IOException} is encountered reading a local asset.
*/
public static final class AssetDataSourceException extends IOException {
public AssetDataSourceException(IOException cause) {
super(cause);
}
}
private final AssetManager assetManager;
@Nullable private Uri uri;
@Nullable private InputStream inputStream;
private long bytesRemaining;
private boolean opened;
/** @param context A context. */
public AssetDataSource(Context context) {
super(/* isNetwork= */ false);
this.assetManager = context.getAssets();
}
@Override
public long open(DataSpec dataSpec) throws AssetDataSourceException {
try {
uri = dataSpec.uri;
String path = Assertions.checkNotNull(uri.getPath());
if (path.startsWith("/android_asset/")) {
path = path.substring(15);
} else if (path.startsWith("/")) {
path = path.substring(1);
}
transferInitializing(dataSpec);
inputStream = assetManager.open(path, AssetManager.ACCESS_RANDOM);
long skipped = inputStream.skip(dataSpec.position);
if (skipped < dataSpec.position) {
// assetManager.open() returns an AssetInputStream, whose skip() implementation only skips
// fewer bytes than requested if the skip is beyond the end of the asset's data.
throw new EOFException();
}
if (dataSpec.length != C.LENGTH_UNSET) {
bytesRemaining = dataSpec.length;
} else {
bytesRemaining = inputStream.available();
if (bytesRemaining == Integer.MAX_VALUE) {
// assetManager.open() returns an AssetInputStream, whose available() implementation
// returns Integer.MAX_VALUE if the remaining length is greater than (or equal to)
// Integer.MAX_VALUE. We don't know the true length in this case, so treat as unbounded.
bytesRemaining = C.LENGTH_UNSET;
}
}
} catch (IOException e) {
throw new AssetDataSourceException(e);
}
opened = true;
transferStarted(dataSpec);
return bytesRemaining;
}
@Override
public int read(byte[] buffer, int offset, int readLength) throws AssetDataSourceException {
if (readLength == 0) {
return 0;
} else if (bytesRemaining == 0) {
return C.RESULT_END_OF_INPUT;
}
int bytesRead;
try {
int bytesToRead = bytesRemaining == C.LENGTH_UNSET ? readLength
: (int) Math.min(bytesRemaining, readLength);
bytesRead = castNonNull(inputStream).read(buffer, offset, bytesToRead);
} catch (IOException e) {
throw new AssetDataSourceException(e);
}
if (bytesRead == -1) {
if (bytesRemaining != C.LENGTH_UNSET) {
// End of stream reached having not read sufficient data.
throw new AssetDataSourceException(new EOFException());
}
return C.RESULT_END_OF_INPUT;
}
if (bytesRemaining != C.LENGTH_UNSET) {
bytesRemaining -= bytesRead;
}
bytesTransferred(bytesRead);
return bytesRead;
}
@Override
@Nullable
public Uri getUri() {
return uri;
}
@Override
public void close() throws AssetDataSourceException {
uri = null;
try {
if (inputStream != null) {
inputStream.close();
}
} catch (IOException e) {
throw new AssetDataSourceException(e);
} finally {
inputStream = null;
if (opened) {
opened = false;
transferEnded();
}
}
}
}
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