SequenceableLoader.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;
import androidx.media3.common.C;
import androidx.media3.common.util.UnstableApi;
// TODO: Clarify the requirements for implementing this interface [Internal ref: b/36250203].
/** A loader that can proceed in approximate synchronization with other loaders. */
@UnstableApi
public interface SequenceableLoader {
/** A callback to be notified of {@link SequenceableLoader} events. */
interface Callback<T extends SequenceableLoader> {
/**
* Called by the loader to indicate that it wishes for its {@link #continueLoading(long)} method
* to be called when it can continue to load data. Called on the playback thread.
*/
void onContinueLoadingRequested(T source);
}
/**
* Returns an estimate of the position up to which data is buffered.
*
* @return An estimate of the absolute position in microseconds up to which data is buffered, or
* {@link C#TIME_END_OF_SOURCE} if the data is fully buffered.
*/
long getBufferedPositionUs();
/** Returns the next load time, or {@link C#TIME_END_OF_SOURCE} if loading has finished. */
long getNextLoadPositionUs();
/**
* Attempts to continue loading.
*
* @param positionUs The current playback position in microseconds. If playback of the period to
* which this loader belongs has not yet started, the value will be the starting position in
* the period minus the duration of any media in previous periods still to be played.
* @return True if progress was made, meaning that {@link #getNextLoadPositionUs()} will return a
* different value than prior to the call. False otherwise.
*/
boolean continueLoading(long positionUs);
/** Returns whether the loader is currently loading. */
boolean isLoading();
/**
* Re-evaluates the buffer given the playback position.
*
* <p>Re-evaluation may discard buffered media or cancel ongoing loads so that media can be
* re-buffered in a different quality.
*
* @param positionUs The current playback position in microseconds. If playback of this period has
* not yet started, the value will be the starting position in this period minus the duration
* of any media in previous periods still to be played.
*/
void reevaluateBuffer(long positionUs);
}