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

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

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/*
 * Copyright 2012-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.facebook.buck.step.ExecutionContext;
import com.facebook.buck.step.Step;
import com.facebook.buck.util.ProjectFilesystem;
import com.google.common.collect.ImmutableSet;
import com.google.common.hash.Hashing;
import com.google.common.io.ByteStreams;

import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Path;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

/**
 * A command that creates a copy of a ZIP archive, making sure that certain user-specified entries
 * are packed with a certain compression level.
 *
 * Can be used, for instance, to force the resources.arsc file in an Android .apk to be compressed.
 */
public class RepackZipEntriesStep implements Step {

    private final Path inputPath;
    private final Path outputPath;
    private final ImmutableSet<String> entries;
    private final int compressionLevel;

    /**
     * Creates a {@link RepackZipEntriesStep}. A temporary directory will be created and used
     * to extract entries. Entries will be packed with the maximum compression level.
     * @param inputPath input archive
     * @param outputPath destination archive
     * @param entries files to repack (e.g. {@code ImmutableSet.of("resources.arsc")})
     */
    public RepackZipEntriesStep(Path inputPath, Path outputPath, ImmutableSet<String> entries) {
        this(inputPath, outputPath, entries, ZipStep.MAX_COMPRESSION_LEVEL);
    }

    /**
     * Creates a {@link RepackZipEntriesStep}.
     * @param inputPath input archive
     * @param outputPath destination archive
     * @param entries files to repack (e.g. {@code ImmutableSet.of("resources.arsc")})
     * @param compressionLevel 0 to 9
     */
    public RepackZipEntriesStep(Path inputPath, Path outputPath, ImmutableSet<String> entries,
            int compressionLevel) {
        this.inputPath = inputPath;
        this.outputPath = outputPath;
        this.entries = entries;
        this.compressionLevel = compressionLevel;
    }

    @Override
    public int execute(ExecutionContext context) {
        ProjectFilesystem filesystem = context.getProjectFilesystem();
        File inputFile = filesystem.getFileForRelativePath(inputPath);
        File outputFile = filesystem.getFileForRelativePath(outputPath);
        try (ZipInputStream in = new ZipInputStream(new BufferedInputStream(new FileInputStream(inputFile)));
                CustomZipOutputStream out = ZipOutputStreams.newOutputStream(outputFile)) {
            for (ZipEntry entry = in.getNextEntry(); entry != null; entry = in.getNextEntry()) {
                CustomZipEntry customEntry = new CustomZipEntry(entry);
                if (entries.contains(customEntry.getName())) {
                    customEntry.setCompressionLevel(compressionLevel);
                }

                InputStream toUse;
                // If we're using STORED files, we must pre-calculate the CRC.
                if (customEntry.getMethod() == ZipEntry.STORED) {
                    try (ByteArrayOutputStream bos = new ByteArrayOutputStream()) {
                        ByteStreams.copy(in, bos);
                        byte[] bytes = bos.toByteArray();
                        customEntry.setCrc(Hashing.crc32().hashBytes(bytes).padToLong());
                        customEntry.setSize(bytes.length);
                        customEntry.setCompressedSize(bytes.length);
                        toUse = new ByteArrayInputStream(bytes);
                    }
                } else {
                    toUse = in;
                }

                out.putNextEntry(customEntry);
                ByteStreams.copy(toUse, out);
                out.closeEntry();
            }

            return 0;
        } catch (IOException e) {
            context.logError(e, "Unable to repack zip");
            return 1;
        }
    }

    @Override
    public String getShortName() {
        return "repack zip";
    }

    @Override
    public String getDescription(ExecutionContext context) {
        return String.format("repack %s in %s", inputPath, outputPath);
    }
}