com.facebook.buck.java.abi.DirectoryWalker.java Source code

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Here is the source code for com.facebook.buck.java.abi.DirectoryWalker.java

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/*
 * Copyright 2014-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.java.abi;

import com.google.common.base.Preconditions;
import com.google.common.collect.Sets;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.Set;

/**
 * A {@link Walker} which operates on all files in a directory in sorted order.
 */
class DirectoryWalker implements Walker {
    private final Path root;

    public DirectoryWalker(Path root) {
        this.root = Preconditions.checkNotNull(root);
    }

    @Override
    public void walk(final FileAction onFile) throws IOException {

        // First find all dir entries and sort them to create a deterministic iteration order.
        final Set<Path> files = Sets.newTreeSet();
        SimpleFileVisitor<Path> visitor = new SimpleFileVisitor<Path>() {
            @Override
            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
                Path relativized = root.relativize(file);
                files.add(relativized);

                return FileVisitResult.CONTINUE;
            }
        };
        Files.walkFileTree(root, visitor);

        // Now call the action on each of the files.
        for (Path path : files) {
            try (InputStream is = Files.newInputStream(root.resolve(path));
                    BufferedInputStream bis = new BufferedInputStream(is)) {
                onFile.visit(path, bis);
            }
        }
    }
}