// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
package com.google.protobuf;
import static com.google.protobuf.Internal.checkNotNull;
import com.google.protobuf.Internal.EnumLite;
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;
/**
* Internal representation of map fields in generated lite-runtime messages.
*
* <p>This class is a protobuf implementation detail. Users shouldn't use this class directly.
*/
public final class MapFieldLite<K, V> extends LinkedHashMap<K, V> {
private boolean isMutable;
private MapFieldLite() {
this.isMutable = true;
}
private MapFieldLite(Map<K, V> mapData) {
super(mapData);
this.isMutable = true;
}
@SuppressWarnings({"rawtypes", "unchecked"})
private static final MapFieldLite EMPTY_MAP_FIELD = new MapFieldLite<>();
static {
EMPTY_MAP_FIELD.makeImmutable();
}
/** Returns an singleton immutable empty MapFieldLite instance. */
@SuppressWarnings({"unchecked", "cast"})
public static <K, V> MapFieldLite<K, V> emptyMapField() {
return (MapFieldLite<K, V>) EMPTY_MAP_FIELD;
}
public void mergeFrom(MapFieldLite<K, V> other) {
ensureMutable();
if (!other.isEmpty()) {
putAll(other);
}
}
@SuppressWarnings({"unchecked", "cast"})
@Override
public Set<Map.Entry<K, V>> entrySet() {
return isEmpty() ? Collections.<Map.Entry<K, V>>emptySet() : super.entrySet();
}
@Override
public void clear() {
ensureMutable();
super.clear();
}
@Override
public V put(K key, V value) {
ensureMutable();
checkNotNull(key);
checkNotNull(value);
return super.put(key, value);
}
public V put(Map.Entry<K, V> entry) {
return put(entry.getKey(), entry.getValue());
}
@Override
public void putAll(Map<? extends K, ? extends V> m) {
ensureMutable();
checkForNullKeysAndValues(m);
super.putAll(m);
}
@Override
public V remove(Object key) {
ensureMutable();
return super.remove(key);
}
private static void checkForNullKeysAndValues(Map<?, ?> m) {
for (Object key : m.keySet()) {
checkNotNull(key);
checkNotNull(m.get(key));
}
}
private static boolean equals(Object a, Object b) {
if (a instanceof byte[] && b instanceof byte[]) {
return Arrays.equals((byte[]) a, (byte[]) b);
}
return a.equals(b);
}
/**
* Checks whether two {@link Map}s are equal. We don't use the default equals method of {@link
* Map} because it compares by identity not by content for byte arrays.
*/
static <K, V> boolean equals(Map<K, V> a, Map<K, V> b) {
if (a == b) {
return true;
}
if (a.size() != b.size()) {
return false;
}
for (Map.Entry<K, V> entry : a.entrySet()) {
if (!b.containsKey(entry.getKey())) {
return false;
}
if (!equals(entry.getValue(), b.get(entry.getKey()))) {
return false;
}
}
return true;
}
/** Checks whether two map fields are equal. */
@SuppressWarnings("unchecked")
@Override
public boolean equals(Object object) {
return (object instanceof Map) && equals(this, (Map<K, V>) object);
}
private static int calculateHashCodeForObject(Object a) {
if (a instanceof byte[]) {
return Internal.hashCode((byte[]) a);
}
// Enums should be stored as integers internally.
if (a instanceof EnumLite) {
throw new UnsupportedOperationException();
}
return a.hashCode();
}
/**
* Calculates the hash code for a {@link Map}. We don't use the default hash code method of {@link
* Map} because for byte arrays and protobuf enums it use {@link Object#hashCode()}.
*/
static <K, V> int calculateHashCodeForMap(Map<K, V> a) {
int result = 0;
for (Map.Entry<K, V> entry : a.entrySet()) {
result +=
calculateHashCodeForObject(entry.getKey()) ^ calculateHashCodeForObject(entry.getValue());
}
return result;
}
@Override
public int hashCode() {
return calculateHashCodeForMap(this);
}
private static Object copy(Object object) {
if (object instanceof byte[]) {
byte[] data = (byte[]) object;
return Arrays.copyOf(data, data.length);
}
return object;
}
/**
* Makes a deep copy of a {@link Map}. Immutable objects in the map will be shared (e.g.,
* integers, strings, immutable messages) and mutable ones will have a copy (e.g., byte arrays,
* mutable messages).
*/
@SuppressWarnings("unchecked")
static <K, V> Map<K, V> copy(Map<K, V> map) {
Map<K, V> result = new LinkedHashMap<K, V>();
for (Map.Entry<K, V> entry : map.entrySet()) {
result.put(entry.getKey(), (V) copy(entry.getValue()));
}
return result;
}
/** Returns a deep copy of this map field. */
public MapFieldLite<K, V> mutableCopy() {
return isEmpty() ? new MapFieldLite<K, V>() : new MapFieldLite<K, V>(this);
}
/**
* Makes this field immutable. All subsequent modifications will throw an {@link
* UnsupportedOperationException}.
*/
public void makeImmutable() {
isMutable = false;
}
/** Returns whether this field can be modified. */
public boolean isMutable() {
return isMutable;
}
private void ensureMutable() {
if (!isMutable()) {
throw new UnsupportedOperationException();
}
}
}