com.facebook.buck.zip.Unzip.java Source code

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Here is the source code for com.facebook.buck.zip.Unzip.java

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/*
 * Copyright 2013-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.zip;

import com.google.common.collect.ImmutableList;
import com.google.common.io.ByteStreams;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

public class Unzip {

    /** Utility class: do not instantiate. */
    private Unzip() {
    }

    /**
     * Unzips a file to a destination and returns the paths of the written files.
     */
    public static ImmutableList<Path> extractZipFile(String zipFile, String destination,
            boolean overwriteExistingFiles) throws IOException {
        // Create output directory if it does not exist
        File folder = new File(destination);
        // TODO(mbolin): UnzipStep could be a CompositeStep with a MakeCleanDirectoryStep for the output
        // dir.
        Files.createDirectories(folder.toPath());

        ImmutableList.Builder<Path> filesWritten = ImmutableList.builder();
        try (ZipInputStream zip = new ZipInputStream(new FileInputStream(zipFile))) {
            for (ZipEntry entry = zip.getNextEntry(); entry != null; entry = zip.getNextEntry()) {
                String fileName = entry.getName();
                File target = new File(folder, fileName);
                if (target.exists() && !overwriteExistingFiles) {
                    continue;
                }

                // TODO(mbolin): Keep track of which directories have already been written to avoid
                // making unnecessary Files.createDirectories() calls. In practice, a single zip file will
                // have many entries in the same directory.

                if (entry.isDirectory()) {
                    // Create the directory and all its parent directories
                    Files.createDirectories(target.toPath());
                } else {
                    // Create parent folder
                    Files.createDirectories(target.toPath().getParent());

                    filesWritten.add(target.toPath());
                    // Write file
                    try (FileOutputStream out = new FileOutputStream(target)) {
                        ByteStreams.copy(zip, out);
                    }
                }
            }
        }
        return filesWritten.build();
    }

}