FullSegmentEncryptionKeyCache.java
/*
* Copyright (C) 2019 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.hls;
import android.net.Uri;
import androidx.annotation.Nullable;
import androidx.media3.common.util.Assertions;
import java.util.LinkedHashMap;
import java.util.Map;
/**
* LRU cache that holds up to {@code maxSize} full-segment-encryption keys. Which each addition,
* once the cache's size exceeds {@code maxSize}, the oldest item (according to insertion order) is
* removed.
*/
/* package */ final class FullSegmentEncryptionKeyCache {
private final LinkedHashMap<Uri, byte[]> backingMap;
public FullSegmentEncryptionKeyCache(int maxSize) {
backingMap =
new LinkedHashMap<Uri, byte[]>(
/* initialCapacity= */ maxSize + 1, /* loadFactor= */ 1, /* accessOrder= */ false) {
@Override
protected boolean removeEldestEntry(Map.Entry<Uri, byte[]> eldest) {
return size() > maxSize;
}
};
}
/**
* Returns the {@code encryptionKey} cached against this {@code uri}, or null if {@code uri} is
* null or not present in the cache.
*/
@Nullable
public byte[] get(@Nullable Uri uri) {
if (uri == null) {
return null;
}
return backingMap.get(uri);
}
/**
* Inserts an entry into the cache.
*
* @throws NullPointerException if {@code uri} or {@code encryptionKey} are null.
*/
@Nullable
public byte[] put(Uri uri, byte[] encryptionKey) {
return backingMap.put(Assertions.checkNotNull(uri), Assertions.checkNotNull(encryptionKey));
}
/**
* Returns true if {@code uri} is present in the cache.
*
* @throws NullPointerException if {@code uri} is null.
*/
public boolean containsUri(Uri uri) {
return backingMap.containsKey(Assertions.checkNotNull(uri));
}
/**
* Removes {@code uri} from the cache. If {@code uri} was present in the cahce, this returns the
* corresponding {@code encryptionKey}, otherwise null.
*
* @throws NullPointerException if {@code uri} is null.
*/
@Nullable
public byte[] remove(Uri uri) {
return backingMap.remove(Assertions.checkNotNull(uri));
}
}