com.google.devtools.build.lib.bazel.repository.CompressedTarFunction.java Source code

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Here is the source code for com.google.devtools.build.lib.bazel.repository.CompressedTarFunction.java

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// Copyright 2015 The Bazel Authors. All rights reserved.
//
// 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.google.devtools.build.lib.bazel.repository;

import com.google.common.base.Optional;
import com.google.devtools.build.lib.bazel.repository.DecompressorValue.Decompressor;
import com.google.devtools.build.lib.rules.repository.RepositoryFunction.RepositoryFunctionException;
import com.google.devtools.build.lib.vfs.FileSystemUtils;
import com.google.devtools.build.lib.vfs.Path;
import com.google.devtools.build.lib.vfs.PathFragment;
import com.google.devtools.build.skyframe.SkyFunctionException.Transience;

import java.util.Date;
import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;

import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;

/**
 * Common code for unarchiving a compressed TAR file.
 */
public abstract class CompressedTarFunction implements Decompressor {
    protected abstract InputStream getDecompressorStream(DecompressorDescriptor descriptor) throws IOException;

    @Override
    public Path decompress(DecompressorDescriptor descriptor) throws RepositoryFunctionException {
        Optional<String> prefix = descriptor.prefix();
        boolean foundPrefix = false;

        try (InputStream decompressorStream = getDecompressorStream(descriptor)) {
            TarArchiveInputStream tarStream = new TarArchiveInputStream(decompressorStream);
            TarArchiveEntry entry;
            while ((entry = tarStream.getNextTarEntry()) != null) {
                StripPrefixedPath entryPath = StripPrefixedPath.maybeDeprefix(entry.getName(), prefix);
                foundPrefix = foundPrefix || entryPath.foundPrefix();
                if (entryPath.skip()) {
                    continue;
                }

                Path filename = descriptor.repositoryPath().getRelative(entryPath.getPathFragment());
                FileSystemUtils.createDirectoryAndParents(filename.getParentDirectory());
                if (entry.isDirectory()) {
                    FileSystemUtils.createDirectoryAndParents(filename);
                } else {
                    if (entry.isSymbolicLink() || entry.isLink()) {
                        PathFragment linkName = new PathFragment(entry.getLinkName());
                        boolean wasAbsolute = linkName.isAbsolute();
                        // Strip the prefix from the link path if set.
                        linkName = StripPrefixedPath.maybeDeprefix(linkName.getPathString(), prefix)
                                .getPathFragment();
                        if (wasAbsolute) {
                            // Recover the path to an absolute path as maybeDeprefix() relativize the path
                            // even if the prefix is not set
                            linkName = descriptor.repositoryPath().getRelative(linkName).asFragment();
                        }
                        if (entry.isSymbolicLink()) {
                            FileSystemUtils.ensureSymbolicLink(filename, linkName);
                        } else {
                            FileSystemUtils.createHardLink(filename,
                                    descriptor.repositoryPath().getRelative(linkName));
                        }
                    } else {
                        Files.copy(tarStream, filename.getPathFile().toPath(), StandardCopyOption.REPLACE_EXISTING);
                        filename.chmod(entry.getMode());

                        // This can only be done on real files, not links, or it will skip the reader to
                        // the next "real" file to try to find the mod time info.
                        Date lastModified = entry.getLastModifiedDate();
                        filename.setLastModifiedTime(lastModified.getTime());
                    }
                }
            }
        } catch (IOException e) {
            throw new RepositoryFunctionException(e, Transience.TRANSIENT);
        }

        if (prefix.isPresent() && !foundPrefix) {
            throw new RepositoryFunctionException(
                    new IOException("Prefix " + prefix.get() + " was given, but not found in the archive"),
                    Transience.PERSISTENT);
        }

        return descriptor.repositoryPath();
    }
}