Files
container/Sources/ContainerizationArchive/ArchiveWriter.swift
T
2025-06-12 09:57:35 -04:00

344 lines
16 KiB
Swift

//===----------------------------------------------------------------------===//
// Copyright © 2025 Apple Inc. and the Containerization project 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
//
// https://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.
//===----------------------------------------------------------------------===//
import CArchive
import Foundation
/// A class responsible for writing archives in various formats.
public final class ArchiveWriter {
var underlying: OpaquePointer!
var delegate: FileArchiveWriterDelegate?
/// Initialize a new `ArchiveWriter` with the given configuration.
/// This method attempts to initialize an empty archive in memory, failing which it throws a `unableToCreateArchive` error.
public init(configuration: ArchiveWriterConfiguration) throws {
// because for some bizarre reason, UTF8 paths won't work unless this process explicitly sets a locale like en_US.UTF-8
try Self.attemptSetLocales(locales: configuration.locales)
guard let underlying = archive_write_new() else { throw ArchiveError.unableToCreateArchive }
self.underlying = underlying
try setFormat(configuration.format)
try addFilter(configuration.filter)
try setOptions(configuration.options)
}
/// Initialize a new `ArchiveWriter` with the given configuration and specified delegate.
private convenience init(configuration: ArchiveWriterConfiguration, delegate: FileArchiveWriterDelegate) throws {
try self.init(configuration: configuration)
self.delegate = delegate
try self.open()
}
private convenience init(configuration: ArchiveWriterConfiguration, file: URL) throws {
try self.init(configuration: configuration, delegate: FileArchiveWriterDelegate(url: file))
}
/// Initialize a new `ArchiveWriter` for writing into the specified file with the given configuration options.
public convenience init(format: Format, filter: Filter, options: [Options] = [], file: URL) throws {
try self.init(
configuration: .init(format: format, filter: filter), delegate: FileArchiveWriterDelegate(url: file))
}
/// Opens the given file for writing data into
public func open(file: URL) throws {
guard let underlying = underlying else { throw ArchiveError.noUnderlyingArchive }
let res = archive_write_open_filename(underlying, file.path)
try wrap(res, ArchiveError.unableToOpenArchive, underlying: underlying)
}
/// Opens the given fd for writing data into
public func open(fileDescriptor: Int32) throws {
guard let underlying = underlying else { throw ArchiveError.noUnderlyingArchive }
let res = archive_write_open_fd(underlying, fileDescriptor)
try wrap(res, ArchiveError.unableToOpenArchive, underlying: underlying)
}
/// Performs any necessary finalizations on the archive and releases resources.
public func finishEncoding() throws {
if let u = underlying {
let r = archive_free(u)
do {
try wrap(r, ArchiveError.unableToCloseArchive, underlying: underlying)
underlying = nil
} catch {
underlying = nil
throw error
}
}
}
deinit {
if let u = underlying {
archive_free(u)
underlying = nil
}
}
private static func attemptSetLocales(locales: [String]) throws {
for locale in locales {
if setlocale(LC_ALL, locale) != nil {
return
}
}
throw ArchiveError.failedToSetLocale(locales: locales)
}
}
extension ArchiveWriter {
fileprivate func open() throws {
guard let underlying = underlying else { throw ArchiveError.noUnderlyingArchive }
// TODO: to be or not to be retained, that is the question
let pointerToSelf = Unmanaged.passUnretained(self).toOpaque()
let res = archive_write_open2(
underlying,
pointerToSelf,
/// The open callback is invoked by archive_write_open(). It should return ARCHIVE_OK if the underlying file or data source is successfully opened. If the open fails, it should call archive_set_error() to register an error code and message and return ARCHIVE_FATAL. Please note that
/// if open fails, close is not called and resources must be freed inside the open callback or with the free callback.
{ underlying, pointerToSelf in
do {
guard let pointerToSelf = pointerToSelf else {
throw ArchiveError.noArchiveInCallback
}
let archive: ArchiveWriter = Unmanaged.fromOpaque(pointerToSelf).takeUnretainedValue()
guard let delegate = archive.delegate else {
throw ArchiveError.noDelegateConfigured
}
try delegate.open(archive: archive)
return ARCHIVE_OK
} catch {
archive_set_error_wrapper(underlying, ARCHIVE_FATAL, "\(error)")
return ARCHIVE_FATAL
}
},
/// The write callback is invoked whenever the library needs to write raw bytes to the archive. For correct blocking, each call to the write callback function should translate into a single write(2) system call. This is especially critical when writing archives to tape drives. On
/// success, the write callback should return the number of bytes actually written. On error, the callback should invoke archive_set_error() to register an error code and message and return -1.
{ underlying, pointerToSelf, dataPointer, count in
do {
guard let pointerToSelf = pointerToSelf else {
throw ArchiveError.noArchiveInCallback
}
let archive: ArchiveWriter = Unmanaged.fromOpaque(pointerToSelf).takeUnretainedValue()
guard let delegate = archive.delegate else {
throw ArchiveError.noDelegateConfigured
}
return try delegate.write(
archive: archive, buffer: UnsafeRawBufferPointer(start: dataPointer, count: count))
} catch {
archive_set_error_wrapper(underlying, ARCHIVE_FATAL, "\(error)")
return -1
}
},
/// The close callback is invoked by archive_close when the archive processing is complete. If the open callback fails, the close callback is not invoked. The callback should return ARCHIVE_OK on success. On failure, the callback should invoke archive_set_error() to register an
/// error code and message and return
{ underlying, pointerToSelf in
do {
guard let pointerToSelf = pointerToSelf else {
throw ArchiveError.noArchiveInCallback
}
let archive: ArchiveWriter = Unmanaged.fromOpaque(pointerToSelf).takeUnretainedValue()
guard let delegate = archive.delegate else {
throw ArchiveError.noDelegateConfigured
}
try delegate.close(archive: archive)
return ARCHIVE_OK
} catch {
archive_set_error_wrapper(underlying, ARCHIVE_FATAL, "\(error)")
return ARCHIVE_FATAL
}
},
/// The free callback is always invoked on archive_free. The return code of this callback is not processed.
{ underlying, pointerToSelf in
do {
guard let pointerToSelf = pointerToSelf else {
throw ArchiveError.noArchiveInCallback
}
let archive: ArchiveWriter = Unmanaged.fromOpaque(pointerToSelf).takeUnretainedValue()
guard let delegate = archive.delegate else {
throw ArchiveError.noDelegateConfigured
}
delegate.free(archive: archive)
// TODO: should we balance the Unmanaged refcount here? Need to test for leaks.
return ARCHIVE_OK
} catch {
archive_set_error_wrapper(underlying, ARCHIVE_FATAL, "\(error)")
return ARCHIVE_FATAL
}
}
)
try wrap(res, ArchiveError.unableToOpenArchive, underlying: underlying)
}
}
public class ArchiveWriterTransaction {
private let writer: ArchiveWriter
fileprivate init(writer: ArchiveWriter) {
self.writer = writer
}
public func writeHeader(entry: WriteEntry) throws {
try writer.writeHeader(entry: entry)
}
public func writeChunk(data: UnsafeRawBufferPointer) throws {
try writer.writeData(data: data)
}
public func finish() throws {
try writer.finishEntry()
}
}
extension ArchiveWriter {
public func makeTransactionWriter() -> ArchiveWriterTransaction {
ArchiveWriterTransaction(writer: self)
}
/// Create a new entry in the archive with the given properties.
/// - Parameters:
/// - entry: A `WriteEntry` object describing the metadata of the entry to be created
/// (e.g., name, modification date, permissions).
/// - data: The `Data` object containing the content for the new entry.
public func writeEntry(entry: WriteEntry, data: Data) throws {
try data.withUnsafeBytes { bytes in
try writeEntry(entry: entry, data: bytes)
}
}
/// Creates a new entry in the archive with the given properties.
///
/// This method performs the following:
/// 1. Writes the archive header using the provided `WriteEntry` metadata.
/// 2. Writes the content from the `UnsafeRawBufferPointer` into the archive.
/// 3. Finalizes the entry in the archive.
///
/// - Parameters:
/// - entry: A `WriteEntry` object describing the metadata of the entry to be created
/// (e.g., name, modification date, permissions, type).
/// - data: An optional `UnsafeRawBufferPointer` containing the raw bytes for the new entry's
/// content. Pass `nil` for entries that do not have content data (e.g., directories, symlinks).
public func writeEntry(entry: WriteEntry, data: UnsafeRawBufferPointer?) throws {
try writeHeader(entry: entry)
if let data = data {
try writeData(data: data)
}
try finishEntry()
}
fileprivate func writeHeader(entry: WriteEntry) throws {
guard let underlying = self.underlying else { throw ArchiveError.noUnderlyingArchive }
try wrap(
archive_write_header(underlying, entry.underlying), ArchiveError.unableToWriteEntryHeader,
underlying: underlying)
}
fileprivate func finishEntry() throws {
guard let underlying = self.underlying else { throw ArchiveError.noUnderlyingArchive }
archive_write_finish_entry(underlying)
}
fileprivate func writeData(data: UnsafeRawBufferPointer) throws {
guard let underlying = self.underlying else { throw ArchiveError.noUnderlyingArchive }
let result = archive_write_data(underlying, data.baseAddress, data.count)
guard result >= 0 else {
throw ArchiveError.unableToWriteData(result)
}
}
}
extension ArchiveWriter {
/// Recursively archives the content of a directory. Regular files, symlinks and directories are added into the archive.
/// Note: Symlinks are added to the archive if both the source and target for the symlink are both contained in the top level directory.
public func archiveDirectory(_ dir: URL) throws {
let fm = FileManager.default
let resourceKeys = Set<URLResourceKey>([
.fileSizeKey, .fileResourceTypeKey,
.creationDateKey, .contentAccessDateKey, .contentModificationDateKey, .fileSecurityKey,
])
guard let directoryEnumerator = fm.enumerator(at: dir, includingPropertiesForKeys: Array(resourceKeys), options: .producesRelativePathURLs) else {
throw POSIXError(.ENOTDIR)
}
for case let fileURL as URL in directoryEnumerator {
var mode = mode_t()
var uid = uid_t()
var gid = gid_t()
let resourceValues = try fileURL.resourceValues(forKeys: resourceKeys)
guard let type = resourceValues.fileResourceType else {
throw ArchiveError.failedToGetProperty(fileURL.path(), .fileResourceTypeKey)
}
let allowedTypes: [URLFileResourceType] = [.directory, .regular, .symbolicLink]
guard allowedTypes.contains(type) else {
continue
}
var size: Int64 = 0
let entry = WriteEntry()
if type == .regular {
guard let _size = resourceValues.fileSize else {
throw ArchiveError.failedToGetProperty(fileURL.path(), .fileSizeKey)
}
size = Int64(_size)
} else if type == .symbolicLink {
let target = fileURL.resolvingSymlinksInPath().absoluteString
let root = dir.absoluteString
guard target.hasPrefix(root) else {
continue
}
let linkTarget = target.dropFirst(root.count + 1)
entry.symlinkTarget = String(linkTarget)
}
guard let created = resourceValues.creationDate else {
throw ArchiveError.failedToGetProperty(fileURL.path(), .creationDateKey)
}
guard let access = resourceValues.contentAccessDate else {
throw ArchiveError.failedToGetProperty(fileURL.path(), .contentAccessDateKey)
}
guard let modified = resourceValues.contentModificationDate else {
throw ArchiveError.failedToGetProperty(fileURL.path(), .contentModificationDateKey)
}
guard let perms = resourceValues.fileSecurity else {
throw ArchiveError.failedToGetProperty(fileURL.path(), .fileSecurityKey)
}
CFFileSecurityGetMode(perms, &mode)
CFFileSecurityGetOwner(perms, &uid)
CFFileSecurityGetGroup(perms, &gid)
entry.path = fileURL.relativePath
entry.size = size
entry.creationDate = created
entry.modificationDate = modified
entry.contentAccessDate = access
entry.fileType = type
entry.group = gid
entry.owner = uid
entry.permissions = mode
if type == .regular {
let p = dir.appending(path: fileURL.relativePath)
let data = try Data(contentsOf: p, options: .uncached)
try self.writeEntry(entry: entry, data: data)
} else {
try self.writeHeader(entry: entry)
}
}
}
}