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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 android.net.Uri;
import androidx.annotation.Nullable;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Assertions;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.PriorityTaskManager;
import java.io.IOException;
import java.util.List;
import java.util.Map;
/**
* A {@link DataSource} that can be used as part of a task registered with a
* {@link PriorityTaskManager}.
* <p>
* Calls to {@link #open(DataSpec)} and {@link #read(byte[], int, int)} are allowed to proceed only
* if there are no higher priority tasks registered to the {@link PriorityTaskManager}. If there
* exists a higher priority task then {@link PriorityTaskManager.PriorityTooLowException} is thrown.
* <p>
* Instances of this class are intended to be used as parts of (possibly larger) tasks that are
* registered with the {@link PriorityTaskManager}, and hence do <em>not</em> register as tasks
* themselves.
*/
public final class PriorityDataSource implements DataSource {
private final DataSource upstream;
private final PriorityTaskManager priorityTaskManager;
private final int priority;
/**
* @param upstream The upstream {@link DataSource}.
* @param priorityTaskManager The priority manager to which the task is registered.
* @param priority The priority of the task.
*/
public PriorityDataSource(DataSource upstream, PriorityTaskManager priorityTaskManager,
int priority) {
this.upstream = Assertions.checkNotNull(upstream);
this.priorityTaskManager = Assertions.checkNotNull(priorityTaskManager);
this.priority = priority;
}
@Override
public void addTransferListener(TransferListener transferListener) {
upstream.addTransferListener(transferListener);
}
@Override
public long open(DataSpec dataSpec) throws IOException {
priorityTaskManager.proceedOrThrow(priority);
return upstream.open(dataSpec);
}
@Override
public int read(byte[] buffer, int offset, int max) throws IOException {
priorityTaskManager.proceedOrThrow(priority);
return upstream.read(buffer, offset, max);
}
@Override
@Nullable
public Uri getUri() {
return upstream.getUri();
}
@Override
public Map<String, List<String>> getResponseHeaders() {
return upstream.getResponseHeaders();
}
@Override
public void close() throws IOException {
upstream.close();
}
}
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