Shell.swift

//
//  Shell.swift
//  PerfectAssistant2
//
//  Created by Kyle Jessup on 2017-03-30.
//  Copyright © 2017 PerfectlySoft. All rights reserved.
//

import Foundation
import PerfectLib

extension File {
	func switchToNonBlocking() {
		guard self.isOpen else {
			return
		}
		let fd = Int32(self.fd)
		let flags = fcntl(fd, F_GETFL)
		guard flags >= 0 else {
			return
		}
		let _ = fcntl(fd, F_SETFL, flags | O_NONBLOCK)
		var one = Int32(1)
		setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, UInt32(MemoryLayout<Int32>.size))
		setsockopt(fd, SOL_SOCKET, SO_NOSIGPIPE, &one, UInt32(MemoryLayout<Int32>.size));
	}
}

private var pathFromShell: String {
	do {
		let shell = ProcessInfo.processInfo.environment["SHELL"] ?? "/bin/bash"
		let env = [
			("HOME", ProcessInfo.processInfo.environment["HOME"]!),
			("LANG", "en_CA.UTF-8"),
			("DISABLE_AUTO_UPDATE", "true")]
		let proc: SysProcess
		switch shell.lastFilePathComponent {
		case "zsh":
			proc = try SysProcess(shell, args: ["-ci", "echo $PATH"], env: env)
		default:
			proc = try SysProcess(shell, args: ["-cl", "echo $PATH"], env: env)
		}
		var read = ""
		while true {
			do {
				guard let s = try proc.stdout?.readSomeBytes(count: 4096) , s.count > 0 else {
					break
				}
				let str = UTF8Encoding.encode(bytes: s)
				read += str
			} catch PerfectLib.PerfectError.fileError(let code, _) {
				if code != EINTR {
					break
				}
			}
		}
		let res = try proc.wait(hang: true)
		if res == 0 && !read.isEmpty {
			return read
		}
	} catch {
		print("Error thrown while echoing $PATH: \(error)")
	}
	//	print("Returning fallback path")
	return "/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local:/usr/local/Cellar:~/.swiftenv/"
}

func sleep(seconds: Double) {
	guard seconds >= 0.0 else {
		return
	}
	let milliseconds = Int(seconds * 1000.0)
	var tv = timeval()
	tv.tv_sec = milliseconds/1000
	tv.tv_usec = Int32((milliseconds%1000)*1000)
	select(0, nil, nil, nil, &tv)
}

func runProc(_ cmd: String, args: [String], envs: [String:String] = [:], quoteArgs: Bool = true, stderr: Bool = false, cd: String? = nil, read: ((String) -> ())? = nil) throws {
	var ienvs = [("PATH", pathFromShell),
	             ("HOME", ProcessInfo.processInfo.environment["HOME"]!),
	             ("LANG", "en_CA.UTF-8"),
	             ("DISABLE_AUTO_UPDATE", "true")]
	for e in envs {
		ienvs.append(e)
	}
	let cmdPath = File(cmd).path
	var newCmd: String
	if let cd = cd {
		newCmd = "cd '\(cd)' && '\(cmdPath)\'"
	} else {
		newCmd = "'\(cmdPath)\'"
	}
	
	for n in 1...args.count {
		if quoteArgs {
			newCmd.append(" \"${\(n)}\"")
		} else {
			newCmd.append(" ${\(n)}")
		}
	}
	let shell = "/bin/sh"
	let proc = try SysProcess(shell, args: ["--login", "-ci", newCmd, cmdPath] + args, env: ienvs)
	let out: File? = stderr ? proc.stderr : proc.stdout
	if let read = read {
		while true {
			do {
				guard let s = try out?.readSomeBytes(count: 4096) , s.count > 0 else {
					break
				}
				let str = UTF8Encoding.encode(bytes: s)
				read(str.replacingOccurrences(of: "sh: no job control in this shell\n", with: ""))
			} catch PerfectLib.PerfectError.fileError(let code, _) {
				if code != EINTR {
					break
				}
			}
		}
	}
	let res = try proc.wait(hang: true)
	if res != 0 {
		let s = try proc.stderr?.readString()
		throw PerfectError.systemError(Int32(res), s!.replacingOccurrences(of: "sh: no job control in this shell\n", with: ""))
	}
}

func runProc(_ cmd: String, args: [String], envs: [String:String], quoteArgs: Bool, cd: String? = nil, readStdin: ((String) -> ()), readStderr: ((String) -> ())) throws -> Int {
	var ienvs = [("PATH", pathFromShell),
	             ("HOME", ProcessInfo.processInfo.environment["HOME"]!),
	             ("LANG", "en_CA.UTF-8"),
	             ("DISABLE_AUTO_UPDATE", "true")]
	for e in envs {
		ienvs.append(e)
	}
	let cmdPath = File(cmd).path
	var newCmd: String
	if let cd = cd {
		newCmd = "cd '\(cd)' && '\(cmdPath)\'"
	} else {
		newCmd = "'\(cmdPath)\'"
	}
	for n in 1...args.count {
		if quoteArgs {
			newCmd.append(" \"${\(n)}\"")
		} else {
			newCmd.append(" ${\(n)}")
		}
	}
	let shell = "/bin/sh"
	let proc = try SysProcess(shell, args: ["--login", "-ci", newCmd, cmdPath] + args, env: ienvs)
	
	proc.stdout?.switchToNonBlocking()
	proc.stderr?.switchToNonBlocking()
	
	var res = -1 as Int32
	while proc.isOpen() {
		do {
			res = try proc.wait(hang: false)
			
			var writeStr = ""
			do {
				while let s = try proc.stdout?.readSomeBytes(count: 4096), s.count > 0 {
					let str = UTF8Encoding.encode(bytes: s)
					writeStr.append(str)
				}
			} catch PerfectLib.PerfectError.fileError(let code, _) where code == EAGAIN {}
			if !writeStr.isEmpty {
				readStdin(writeStr.replacingOccurrences(of: "sh: no job control in this shell\n", with: ""))
			}
			
			writeStr = ""
			do {
				while let s = try proc.stderr?.readSomeBytes(count: 4096), s.count > 0 {
					let str = UTF8Encoding.encode(bytes: s)
					writeStr.append(str)
				}
			} catch PerfectLib.PerfectError.fileError(let code, _) where code == EAGAIN {}
			if !writeStr.isEmpty {
				readStderr(writeStr.replacingOccurrences(of: "sh: no job control in this shell\n", with: ""))
			}
			
			sleep(seconds: 0.25)
		} catch PerfectLib.PerfectError.fileError(let code, _) {
			if code != EINTR {
				break
			}
		}
	}
	
	return Int(res)
}