Archive.swift

import Foundation
import Result
import ReactiveSwift
import ReactiveTask

/// Zips the given input paths (recursively) into an archive that will be
/// located at the given URL.
public func zip(paths: [String], into archiveURL: URL, workingDirectory: String) -> SignalProducer<(), CarthageError> {
	precondition(!paths.isEmpty)
	precondition(archiveURL.isFileURL)

	let task = Task("/usr/bin/env", arguments: [ "zip", "-q", "-r", "--symlinks", archiveURL.path ] + paths, workingDirectoryPath: workingDirectory)

	return task.launch()
		.mapError(CarthageError.taskError)
		.then(SignalProducer<(), CarthageError>.empty)
}

/// Unarchives the given file URL into a temporary directory, using its
/// extension to detect archive type, then sends the file URL to that directory.
public func unarchive(archive fileURL: URL) -> SignalProducer<URL, CarthageError> {
	switch fileURL.pathExtension {
	case "gz", "tgz", "bz2", "xz":
		return untar(archive: fileURL)
	default:
		return unzip(archive: fileURL)
	}
}

/// Unzips the archive at the given file URL, extracting into the given
/// directory URL (which must already exist).
private func unzip(archive fileURL: URL, to destinationDirectoryURL: URL) -> SignalProducer<(), CarthageError> {
	precondition(fileURL.isFileURL)
	precondition(destinationDirectoryURL.isFileURL)

	let task = Task("/usr/bin/env", arguments: [ "unzip", "-uo", "-qq", "-d", destinationDirectoryURL.path, fileURL.path ])
	return task.launch()
		.mapError(CarthageError.taskError)
		.then(SignalProducer<(), CarthageError>.empty)
}

/// Untars an archive at the given file URL, extracting into the given
/// directory URL (which must already exist).
private func untar(archive fileURL: URL, to destinationDirectoryURL: URL) -> SignalProducer<(), CarthageError> {
	precondition(fileURL.isFileURL)
	precondition(destinationDirectoryURL.isFileURL)

	let task = Task("/usr/bin/env", arguments: [ "tar", "-xf", fileURL.path, "-C", destinationDirectoryURL.path ])
	return task.launch()
		.mapError(CarthageError.taskError)
		.then(SignalProducer<(), CarthageError>.empty)
}

private let archiveTemplate = "carthage-archive.XXXXXX"

/// Unzips the archive at the given file URL into a temporary directory, then
/// sends the file URL to that directory.
private func unzip(archive fileURL: URL) -> SignalProducer<URL, CarthageError> {
	return FileManager.default.reactive.createTemporaryDirectoryWithTemplate(archiveTemplate)
		.flatMap(.merge) { directoryURL in
			return unzip(archive: fileURL, to: directoryURL)
				.then(SignalProducer<URL, CarthageError>(value: directoryURL))
		}
}

/// Untars an archive at the given file URL into a temporary directory, 
/// then sends the file URL to that directory.
private func untar(archive fileURL: URL) -> SignalProducer<URL, CarthageError> {
	return FileManager.default.reactive.createTemporaryDirectoryWithTemplate(archiveTemplate)
		.flatMap(.merge) { directoryURL in
			return untar(archive: fileURL, to: directoryURL)
				.then(SignalProducer<URL, CarthageError>(value: directoryURL))
		}
}