DefaultContentMetadata.java
/*
* Copyright (C) 2018 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.datasource.cache;
import androidx.annotation.Nullable;
import androidx.media3.common.util.UnstableApi;
import com.google.common.base.Charsets;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
/** Default implementation of {@link ContentMetadata}. Values are stored as byte arrays. */
@UnstableApi
public final class DefaultContentMetadata implements ContentMetadata {
/** An empty DefaultContentMetadata. */
public static final DefaultContentMetadata EMPTY =
new DefaultContentMetadata(Collections.emptyMap());
private int hashCode;
private final Map<String, byte[]> metadata;
public DefaultContentMetadata() {
this(Collections.emptyMap());
}
/**
* @param metadata The metadata entries in their raw byte array form.
*/
public DefaultContentMetadata(Map<String, byte[]> metadata) {
this.metadata = Collections.unmodifiableMap(metadata);
}
/**
* Returns a copy {@link DefaultContentMetadata} with {@code mutations} applied. If {@code
* mutations} don't change anything, returns this instance.
*/
public DefaultContentMetadata copyWithMutationsApplied(ContentMetadataMutations mutations) {
Map<String, byte[]> mutatedMetadata = applyMutations(metadata, mutations);
if (isMetadataEqual(metadata, mutatedMetadata)) {
return this;
}
return new DefaultContentMetadata(mutatedMetadata);
}
/** Returns the set of metadata entries in their raw byte array form. */
public Set<Entry<String, byte[]>> entrySet() {
return metadata.entrySet();
}
@Override
@Nullable
public final byte[] get(String key, @Nullable byte[] defaultValue) {
@Nullable byte[] bytes = metadata.get(key);
if (bytes != null) {
return Arrays.copyOf(bytes, bytes.length);
} else {
return defaultValue;
}
}
@Override
@Nullable
public final String get(String key, @Nullable String defaultValue) {
@Nullable byte[] bytes = metadata.get(key);
if (bytes != null) {
return new String(bytes, Charsets.UTF_8);
} else {
return defaultValue;
}
}
@Override
public final long get(String key, long defaultValue) {
@Nullable byte[] bytes = metadata.get(key);
if (bytes != null) {
return ByteBuffer.wrap(bytes).getLong();
} else {
return defaultValue;
}
}
@Override
public final boolean contains(String key) {
return metadata.containsKey(key);
}
@Override
public boolean equals(@Nullable Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
return isMetadataEqual(metadata, ((DefaultContentMetadata) o).metadata);
}
@Override
public int hashCode() {
if (hashCode == 0) {
int result = 0;
for (Entry<String, byte[]> entry : metadata.entrySet()) {
result += entry.getKey().hashCode() ^ Arrays.hashCode(entry.getValue());
}
hashCode = result;
}
return hashCode;
}
private static boolean isMetadataEqual(Map<String, byte[]> first, Map<String, byte[]> second) {
if (first.size() != second.size()) {
return false;
}
for (Entry<String, byte[]> entry : first.entrySet()) {
byte[] value = entry.getValue();
@Nullable byte[] otherValue = second.get(entry.getKey());
if (!Arrays.equals(value, otherValue)) {
return false;
}
}
return true;
}
private static Map<String, byte[]> applyMutations(
Map<String, byte[]> otherMetadata, ContentMetadataMutations mutations) {
HashMap<String, byte[]> metadata = new HashMap<>(otherMetadata);
removeValues(metadata, mutations.getRemovedValues());
addValues(metadata, mutations.getEditedValues());
return metadata;
}
private static void removeValues(HashMap<String, byte[]> metadata, List<String> names) {
for (int i = 0; i < names.size(); i++) {
metadata.remove(names.get(i));
}
}
private static void addValues(HashMap<String, byte[]> metadata, Map<String, Object> values) {
for (Entry<String, Object> entry : values.entrySet()) {
metadata.put(entry.getKey(), getBytes(entry.getValue()));
}
}
private static byte[] getBytes(Object value) {
if (value instanceof Long) {
return ByteBuffer.allocate(8).putLong((Long) value).array();
} else if (value instanceof String) {
return ((String) value).getBytes(Charsets.UTF_8);
} else if (value instanceof byte[]) {
return (byte[]) value;
} else {
throw new IllegalArgumentException();
}
}
}