DataChunk.java
/*
* 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 androidx.media3.exoplayer.source.chunk;
import androidx.annotation.Nullable;
import androidx.media3.common.C;
import androidx.media3.common.C.DataType;
import androidx.media3.common.Format;
import androidx.media3.common.util.UnstableApi;
import androidx.media3.common.util.Util;
import androidx.media3.datasource.DataSource;
import androidx.media3.datasource.DataSourceUtil;
import androidx.media3.datasource.DataSpec;
import java.io.IOException;
import java.util.Arrays;
/**
* A base class for {@link Chunk} implementations where the data should be loaded into a {@code
* byte[]} before being consumed.
*/
@UnstableApi
public abstract class DataChunk extends Chunk {
private static final int READ_GRANULARITY = 16 * 1024;
private byte[] data;
private volatile boolean loadCanceled;
/**
* @param dataSource The source from which the data should be loaded.
* @param dataSpec Defines the data to be loaded.
* @param type See {@link #type}.
* @param trackFormat See {@link #trackFormat}.
* @param trackSelectionReason See {@link #trackSelectionReason}.
* @param trackSelectionData See {@link #trackSelectionData}.
* @param data An optional recycled array that can be used as a holder for the data.
*/
public DataChunk(
DataSource dataSource,
DataSpec dataSpec,
@DataType int type,
Format trackFormat,
@C.SelectionReason int trackSelectionReason,
@Nullable Object trackSelectionData,
@Nullable byte[] data) {
super(
dataSource,
dataSpec,
type,
trackFormat,
trackSelectionReason,
trackSelectionData,
C.TIME_UNSET,
C.TIME_UNSET);
this.data = data == null ? Util.EMPTY_BYTE_ARRAY : data;
}
/**
* Returns the array in which the data is held.
*
* <p>This method should be used for recycling the holder only, and not for reading the data.
*
* @return The array in which the data is held.
*/
public byte[] getDataHolder() {
return data;
}
// Loadable implementation
@Override
public final void cancelLoad() {
loadCanceled = true;
}
@Override
public final void load() throws IOException {
try {
dataSource.open(dataSpec);
int limit = 0;
int bytesRead = 0;
while (bytesRead != C.RESULT_END_OF_INPUT && !loadCanceled) {
maybeExpandData(limit);
bytesRead = dataSource.read(data, limit, READ_GRANULARITY);
if (bytesRead != -1) {
limit += bytesRead;
}
}
if (!loadCanceled) {
consume(data, limit);
}
} finally {
DataSourceUtil.closeQuietly(dataSource);
}
}
/**
* Called by {@link #load()}. Implementations should override this method to consume the loaded
* data.
*
* @param data An array containing the data.
* @param limit The limit of the data.
* @throws IOException If an error occurs consuming the loaded data.
*/
protected abstract void consume(byte[] data, int limit) throws IOException;
private void maybeExpandData(int limit) {
if (data.length < limit + READ_GRANULARITY) {
// The new length is calculated as (data.length + READ_GRANULARITY) rather than
// (limit + READ_GRANULARITY) in order to avoid small increments in the length.
data = Arrays.copyOf(data, data.length + READ_GRANULARITY);
}
}
}