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Break the inheritance of FullSegmentEncryptionKeyCache

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Use composition instead.

This makes the null-handling more explicit & complete (previous implementation
tried to prevent null values, but didn't override all mutation methods
e.g. replace(), putIfAbsent() etc.)

PiperOrigin-RevId: 274778513
This commit is contained in:
ibaker 2019-10-15 12:46:22 +01:00 committed by Oliver Woodman
parent f133766b40
commit 0ba91811d1
1 changed files with 48 additions and 15 deletions
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63
library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsChunkSource.java
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@ -43,7 +43,6 @@ import java.io.IOException;
import java.util.Arrays;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
/**
* Source of Hls (possibly adaptive) chunks.
@ -505,7 +504,7 @@ import java.util.Map;
if (keyUri == null) {
return null;
}
if (keyCache.containsKey(keyUri)) {
if (keyCache.containsUri(keyUri)) {
// The key is present in the key cache. We re-insert it to prevent it from being evicted by
// the following key addition. Note that removal of the key is necessary to affect the
// eviction order.
@ -660,29 +659,63 @@ import java.util.Map;
* addition, once the cache's size exceeds {@link #KEY_CACHE_SIZE}, the oldest item (according to
* insertion order) is removed.
*/
private static final class FullSegmentEncryptionKeyCache extends LinkedHashMap<Uri, byte[]> {
private static final class FullSegmentEncryptionKeyCache {
private final LinkedHashMap<Uri, byte[]> backingMap;
public FullSegmentEncryptionKeyCache() {
super(
/* initialCapacity= */ KEY_CACHE_SIZE * 2, /* loadFactor= */ 1, /* accessOrder= */ false);
backingMap =
new LinkedHashMap<Uri, byte[]>(
/* initialCapacity= */ KEY_CACHE_SIZE + 1,
/* loadFactor= */ 1,
/* accessOrder= */ false) {
@Override
protected boolean removeEldestEntry(Entry<Uri, byte[]> eldest) {
return size() > KEY_CACHE_SIZE;
}
};
}
@Override
public byte[] get(Object keyUri) {
if (keyUri == null) {
/**
* 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 super.get(keyUri);
return backingMap.get(uri);
}
@Override
public byte[] put(Uri keyUri, byte[] key) {
return super.put(keyUri, Assertions.checkNotNull(key));
/**
* 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));
}
@Override
protected boolean removeEldestEntry(Map.Entry<Uri, byte[]> entry) {
return size() > KEY_CACHE_SIZE;
/**
* 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));
}
}
}