/*
* Copyright 2017 the original author or authors.
*
* 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 org.gradle.api.internal.changedetection.state;
import org.gradle.caching.internal.BuildCacheHasher;
import java.util.Arrays;
import java.util.List;
public class ListValueSnapshot implements ValueSnapshot {
public static final ValueSnapshot EMPTY = new ListValueSnapshot(new ValueSnapshot[0]);
private final ValueSnapshot[] elements;
public ListValueSnapshot(ValueSnapshot[] elements) {
this.elements = elements;
}
public ValueSnapshot[] getElements() {
return elements;
}
@Override
public void appendToHasher(BuildCacheHasher hasher) {
hasher.putString("List");
hasher.putInt(elements.length);
for (ValueSnapshot element : elements) {
element.appendToHasher(hasher);
}
}
@Override
public ValueSnapshot snapshot(Object value, ValueSnapshotter snapshotter) {
if (!(value instanceof List)) {
return snapshotter.snapshot(value);
}
// Find first position where values are different
List<?> list = (List<?>) value;
int pos = 0;
int len = Math.min(elements.length, list.size());
ValueSnapshot newElement = null;
for (; pos < len; pos++) {
ValueSnapshot element = elements[pos];
newElement = snapshotter.snapshot(list.get(pos), element);
if (element != newElement) {
break;
}
}
if (pos == elements.length && pos == list.size()) {
// Same size and no differences
return this;
}
// Copy the snapshots whose values are the same, then snapshot remaining values
ValueSnapshot[] newElements = new ValueSnapshot[list.size()];
System.arraycopy(elements, 0, newElements, 0, pos);
if (pos < list.size()) {
newElements[pos] = newElement;
for (int i = pos + 1; i < list.size(); i++) {
newElements[i] = snapshotter.snapshot(list.get(i));
}
}
return new ListValueSnapshot(newElements);
}
@Override
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (obj == null || obj.getClass() != getClass()) {
return false;
}
ListValueSnapshot other = (ListValueSnapshot) obj;
return Arrays.equals(elements, other.elements);
}
@Override
public int hashCode() {
return Arrays.hashCode(elements);
}
}