| /* |
| * 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.facebook.buck.io.MoreFiles; |
| import com.facebook.buck.io.MorePosixFilePermissions; |
| import com.google.common.collect.ImmutableList; |
| import com.google.common.io.ByteStreams; |
| |
| import org.apache.commons.compress.archivers.zip.ZipArchiveEntry; |
| import org.apache.commons.compress.archivers.zip.ZipFile; |
| |
| import java.io.FileOutputStream; |
| import java.io.IOException; |
| import java.nio.file.Files; |
| import java.nio.file.Path; |
| import java.nio.file.attribute.PosixFilePermission; |
| import java.util.Enumeration; |
| import java.util.Set; |
| |
| 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( |
| Path zipFile, |
| Path destination, |
| boolean overwriteExistingFiles) throws IOException { |
| // Create output directory if it does not exist |
| Files.createDirectories(destination); |
| |
| ImmutableList.Builder<Path> filesWritten = ImmutableList.builder(); |
| try (ZipFile zip = new ZipFile(zipFile.toFile())) { |
| Enumeration<ZipArchiveEntry> entries = zip.getEntries(); |
| while (entries.hasMoreElements()) { |
| ZipArchiveEntry entry = entries.nextElement(); |
| String fileName = entry.getName(); |
| Path target = destination.resolve(fileName); |
| if (Files.exists(target) && !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); |
| } else { |
| // Create parent folder |
| Files.createDirectories(target.getParent()); |
| |
| filesWritten.add(target); |
| // Write file |
| try (FileOutputStream out = new FileOutputStream(target.toFile())) { |
| ByteStreams.copy(zip.getInputStream(entry), out); |
| } |
| |
| // TODO(simons): Implement what the comment below says we should do. |
| // |
| // Sets the file permissions of the output file given the information in {@code entry}'s |
| // extra data field. According to the docs at |
| // http://www.opensource.apple.com/source/zip/zip-6/unzip/unzip/proginfo/extra.fld there |
| // are two extensions that might support file permissions: Acorn and ASi UNIX. We shall |
| // assume that inputs are not from an Acorn SparkFS. The relevant section from the docs: |
| // |
| // <pre> |
| // The following is the layout of the ASi extra block for Unix. The |
| // local-header and central-header versions are identical. |
| // (Last Revision 19960916) |
| // |
| // Value Size Description |
| // ----- ---- ----------- |
| // (Unix3) 0x756e Short tag for this extra block type ("nu") |
| // TSize Short total data size for this block |
| // CRC Long CRC-32 of the remaining data |
| // Mode Short file permissions |
| // SizDev Long symlink'd size OR major/minor dev num |
| // UID Short user ID |
| // GID Short group ID |
| // (var.) variable symbolic link filename |
| // |
| // Mode is the standard Unix st_mode field from struct stat, containing |
| // user/group/other permissions, setuid/setgid and symlink info, etc. |
| // </pre> |
| // |
| // From the stat man page, we see that the following mask values are defined for the file |
| // permissions component of the st_mode field: |
| // |
| // <pre> |
| // S_ISUID 0004000 set-user-ID bit |
| // S_ISGID 0002000 set-group-ID bit (see below) |
| // S_ISVTX 0001000 sticky bit (see below) |
| // |
| // S_IRWXU 00700 mask for file owner permissions |
| // |
| // S_IRUSR 00400 owner has read permission |
| // S_IWUSR 00200 owner has write permission |
| // S_IXUSR 00100 owner has execute permission |
| // |
| // S_IRWXG 00070 mask for group permissions |
| // S_IRGRP 00040 group has read permission |
| // S_IWGRP 00020 group has write permission |
| // S_IXGRP 00010 group has execute permission |
| // |
| // S_IRWXO 00007 mask for permissions for others |
| // (not in group) |
| // S_IROTH 00004 others have read permission |
| // S_IWOTH 00002 others have write permission |
| // S_IXOTH 00001 others have execute permission |
| // </pre> |
| // |
| // For the sake of our own sanity, we're going to assume that no-one is using symlinks, |
| // but we'll check and throw if they are. |
| // |
| // Before we do anything, we should check the header ID. Pfft! |
| // |
| // Having jumped through all these hoops, it turns out that InfoZIP's "unzip" store the |
| // values in the external file attributes of a zip entry (found in the zip's central |
| // directory) assuming that the OS creating the zip was one of an enormous list that |
| // includes UNIX but not Windows, it first searches for the extra fields, and if not found |
| // falls through to a code path that supports MS-DOS and which stores the UNIX file |
| // attributes in the upper 16 bits of the external attributes field. |
| // |
| // We'll support neither approach fully, but we encode whether this file was executable |
| // via storing 0100 in the fields that are typically used by zip implementations to store |
| // POSIX permissions. If we find it was executable, use the platform independent java |
| // interface to make this unpacked file executable. |
| |
| Set<PosixFilePermission> permissions = |
| MorePosixFilePermissions.fromMode(entry.getExternalAttributes() >> 16); |
| if (permissions.contains(PosixFilePermission.OWNER_EXECUTE)) { |
| MoreFiles.makeExecutable(target.toFile()); |
| } |
| |
| } |
| } |
| } |
| return filesWritten.build(); |
| } |
| |
| } |
