/*
 * 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.hash.HashCode;
import org.gradle.api.Nullable;

/**
 * Calculates a hash for a classpath entry (a jar or class file)
 */
public interface ClasspathEntryHasher {
    /**
     * Returns a hash based on the contents of the given fileDetails.
     *
     * May return <code>null</code>, if the file contributes nothing to the classpath.
     *
     * e.g., an empty jar file or a class file with no public API (for compile classpaths).
     */
    @Nullable
    HashCode hash(FileDetails fileDetails);
}
