Process.swift

import Foundation
import PromiseKit
import PMKFoundation
import Path

public typealias ProcessOutput = (status: Int32, out: String, err: String)

extension Process {
    @discardableResult
    static func sudo(_ executable: Path, workingDirectory: URL? = nil, _ arguments: String...) -> Promise<ProcessOutput> {
        run(Path.root.usr.bin.sudo.url, workingDirectory: workingDirectory, [executable.string] + arguments)
    }

    @discardableResult
    static func run(_ executable: Path, workingDirectory: URL? = nil, input: String? = nil, _ arguments: String...) -> Promise<ProcessOutput> {
        return run(executable.url, workingDirectory: workingDirectory, input: input, arguments)
    }

    @discardableResult
    static func run(_ executable: URL, workingDirectory: URL? = nil, input: String? = nil, _ arguments: [String]) -> Promise<ProcessOutput> {
        let process = Process()
        process.currentDirectoryURL = workingDirectory ?? executable.deletingLastPathComponent()
        process.executableURL = executable
        process.arguments = arguments
        if let input = input {
            let inputPipe = Pipe()
            process.standardInput = inputPipe.fileHandleForReading
            inputPipe.fileHandleForWriting.write(Data(input.utf8))
            inputPipe.fileHandleForWriting.closeFile()
        }
        return process.launch(.promise).map { std in 
            let output = String(data: std.out.fileHandleForReading.readDataToEndOfFile(), encoding: .utf8) ?? ""
            let error = String(data: std.err.fileHandleForReading.readDataToEndOfFile(), encoding: .utf8) ?? ""
            return (process.terminationStatus, output, error)
        }
    }
}