/*
* 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 com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import org.gradle.api.UncheckedIOException;
import org.gradle.internal.classloader.ClassLoaderHierarchyHasher;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.lang.reflect.Array;
import java.util.List;
import java.util.Map;
import java.util.Set;
public class ValueSnapshotter {
private final ClassLoaderHierarchyHasher classLoaderHasher;
public ValueSnapshotter(ClassLoaderHierarchyHasher classLoaderHasher) {
this.classLoaderHasher = classLoaderHasher;
}
/**
* Creates a snapshot of the given value.
*
* @throws UncheckedIOException On failure to snapshot the value.
*/
public ValueSnapshot snapshot(Object value) throws UncheckedIOException {
if (value == null) {
return NullValueSnapshot.INSTANCE;
}
if (value instanceof String) {
return new StringValueSnapshot((String) value);
}
if (value instanceof Boolean) {
return value.equals(Boolean.TRUE) ? BooleanValueSnapshot.TRUE : BooleanValueSnapshot.FALSE;
}
if (value instanceof List) {
List<?> list = (List<?>) value;
if (list.size() == 0) {
return ListValueSnapshot.EMPTY;
}
ValueSnapshot[] elements = new ValueSnapshot[list.size()];
for (int i = 0; i < list.size(); i++) {
Object element = list.get(i);
elements[i] = snapshot(element);
}
return new ListValueSnapshot(elements);
}
if (value instanceof Enum) {
return new EnumValueSnapshot((Enum) value);
}
if (value.getClass().equals(File.class)) {
// Not subtypes as we don't know whether they are immutable or not
return new FileValueSnapshot((File) value);
}
if (value instanceof Number) {
if (value instanceof Integer) {
return new IntegerValueSnapshot((Integer) value);
}
if (value instanceof Long) {
return new LongValueSnapshot((Long) value);
}
if (value instanceof Short) {
return new ShortValueSnapshot((Short) value);
}
}
if (value instanceof Set) {
Set<?> set = (Set<?>) value;
ImmutableSet.Builder<ValueSnapshot> builder = ImmutableSet.builder();
for (Object element : set) {
builder.add(snapshot(element));
}
return new SetValueSnapshot(builder.build());
}
if (value instanceof Map) {
Map<?, ?> map = (Map<?, ?>) value;
ImmutableMap.Builder<ValueSnapshot, ValueSnapshot> builder = new ImmutableMap.Builder<ValueSnapshot, ValueSnapshot>();
for (Map.Entry<?, ?> entry : map.entrySet()) {
builder.put(snapshot(entry.getKey()), snapshot(entry.getValue()));
}
return new MapValueSnapshot(builder.build());
}
if (value.getClass().isArray()) {
int length = Array.getLength(value);
if (length == 0) {
return ArrayValueSnapshot.EMPTY;
}
ValueSnapshot[] elements = new ValueSnapshot[length];
for (int i = 0; i < length; i++) {
Object element = Array.get(value, i);
elements[i] = snapshot(element);
}
return new ArrayValueSnapshot(elements);
}
// Fall back to serialization
return serialize(value);
}
private SerializedValueSnapshot serialize(Object value) {
ByteArrayOutputStream outputStream;
try {
outputStream = new ByteArrayOutputStream();
ObjectOutputStream objectStr = new ObjectOutputStream(outputStream);
objectStr.writeObject(value);
objectStr.flush();
} catch (IOException e) {
throw new UncheckedIOException(e);
}
return new SerializedValueSnapshot(classLoaderHasher.getClassLoaderHash(value.getClass().getClassLoader()), outputStream.toByteArray());
}
/**
* Creates a snapshot of the given value, given a candidate snapshot. If the value is the same as the value provided by the candidate snapshot, the candidate _must_ be returned.
*/
public ValueSnapshot snapshot(Object value, ValueSnapshot candidate) {
return candidate.snapshot(value, this);
}
}