com.facebook.buck.util.hashing.PathHashing.java Source code

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Here is the source code for com.facebook.buck.util.hashing.PathHashing.java

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/*
 * Copyright 2015-present Facebook, Inc.
 *
 * 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 com.facebook.buck.util.hashing;

import com.facebook.buck.io.file.MorePaths;
import com.facebook.buck.io.filesystem.ProjectFilesystem;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.ImmutableSortedSet;
import com.google.common.hash.Hasher;
import java.io.IOException;
import java.nio.file.Path;
import java.nio.file.Paths;

public class PathHashing {
    // Utility class, do not instantiate.
    private PathHashing() {
    }

    private static final Path EMPTY_PATH = Paths.get("");

    public static ImmutableSet<Path> hashPath(Hasher hasher, ProjectFileHashLoader fileHashLoader,
            ProjectFilesystem projectFilesystem, Path root) throws IOException {
        Preconditions.checkArgument(!root.equals(EMPTY_PATH), "Path to hash (%s) must not be empty", root);
        ImmutableSet.Builder<Path> children = ImmutableSet.builder();
        for (Path path : ImmutableSortedSet.copyOf(projectFilesystem.getFilesUnderPath(root))) {
            StringHashing.hashStringAndLength(hasher, MorePaths.pathWithUnixSeparators(path));
            if (!root.equals(path)) {
                children.add(root.relativize(path));
            }
            hasher.putBytes(fileHashLoader.get(path).asBytes());
        }
        return children.build();
    }
}