Refactoring I.

- Revamp whole DB to Display flow
- Filter Pipeline, arbitrary filtering and sorting
- Binary tree arrays for faster lookup & manipulation
- DB: introducing custom functions
- DB scheme: split req into heap & cache
- cache written by GlassVPN only
- heap written by Main App only
- Introducing DB separation: DBCore, DBCommon, DBAppOnly
- Introducing DB data sources: TestDataSource, GroupedDomainDataSource, RecordingsDB, DomainFilter
- Background sync: Move entries from cache to heap and notify all observers
- GlassVPN: Binary tree filter lookup
- GlassVPN: Reusing prepared statement

main/Extensions/Generic.swift

@@ -16,102 +16,6 @@ struct QLog {
 	}
 }
 
-extension Collection {
-	subscript(ifExist i: Index?) -> Iterator.Element? {
-		guard let i = i else { return nil }
-		return indices.contains(i) ? self[i] : nil
-	}
-}
-
-var listOfSLDs: [String : [String : Bool]] = {
-	let path = Bundle.main.url(forResource: "third-level", withExtension: "txt")
-	let content = try! String(contentsOf: path!)
-	var res: [String : [String : Bool]] = [:]
-	content.enumerateLines { line, _ in
-		let dom = line.split(separator: ".")
-		let tld = String(dom.first!)
-		let sld = String(dom.last!)
-		if res[tld] == nil { res[tld] = [:] }
-		res[tld]![sld] = true
-	}
-	return res
-}()
-
-extension String {
-	/// Check if string is equal to `domain` or ends with `.domain`
-	func isSubdomain(of domain: String) -> Bool { self == domain || self.hasSuffix("." + domain) }
-	/// Split string into top level domain part and host part
-	func splitDomainAndHost() -> (domain: String, host: String?) {
-		let lastChr = last?.asciiValue ?? 0
-		guard lastChr > UInt8(ascii: "9") || lastChr < UInt8(ascii: "0") else { // IP address
-			return (domain: "# IP connection", host: self)
-		}
-		var parts = components(separatedBy: ".")
-		guard let tld = parts.popLast(), let sld = parts.popLast() else {
-			return (domain: self, host: nil) // no subdomains, just plain SLD
-		}
-		var ending = sld + "." + tld
-		if listOfSLDs[tld]?[sld] ?? false, let rld = parts.popLast() {
-			ending = rld + "." + ending
-		}
-		return (domain: ending, host: parts.joined(separator: "."))
-	}
-	/// Returns `true` if String matches list of known second level domains (e.g., `co.uk`).
-	func isKnownSLD() -> Bool {
-		let parts = components(separatedBy: ".")
-		return parts.count == 2 && listOfSLDs[parts.last!]?[parts.first!] ?? false
-	}
-}
-
-extension Timer {
-	@discardableResult static func repeating(_ interval: TimeInterval, call selector: Selector, on target: Any, userInfo: Any? = nil) -> Timer {
-		Timer.scheduledTimer(timeInterval: interval, target: target, selector: selector,
-							 userInfo: userInfo, repeats: true)
-	}
-}
-
-extension DateFormatter {
-	convenience init(withFormat: String) {
-		self.init()
-		dateFormat = withFormat
-	}
-	func with(format: String) -> Self {
-		dateFormat = format
-		return self
-	}
-	func string(from ts: Timestamp) -> String {
-		string(from: Date.init(timeIntervalSince1970: Double(ts)))
-	}
-}
-
-struct TimeFormat {
-	static func from(_ duration: Timestamp) -> String {
-		String(format: "%02d:%02d", duration / 60, duration % 60)
-	}
-	static func from(_ duration: TimeInterval, millis: Bool = false) -> String {
-		let t = Int(duration)
-		if millis {
-			let mil = Int(duration * 1000) % 1000
-			return String(format: "%02d:%02d.%03d", t / 60, t % 60, mil)
-		}
-		return String(format: "%02d:%02d", t / 60, t % 60)
-	}
-	static func since(_ date: Date, millis: Bool = false) -> String {
-		from(Date().timeIntervalSince(date), millis: millis)
-	}
-	/// Formatted duration string, e.g., `20 min` or `7 days`
-	/// - Parameters:
-	///   - minutes: Duration in minutes
-	///   - style: Default: `.short`
-	static func short(minutes: Int, style: DateComponentsFormatter.UnitsStyle = .short) -> String? {
-		let dcf = DateComponentsFormatter()
-		dcf.maximumUnitCount = 1
-		dcf.allowedUnits = [.day, .hour, .minute]
-		dcf.unitsStyle = style
-		return dcf.string(from: DateComponents(minute: minutes))
-	}
-}
-
 extension UIColor {
 	static var sysBg: UIColor { get { if #available(iOS 13.0, *) { return .systemBackground } else { return .white } }}
 	static var sysFg: UIColor { get { if #available(iOS 13.0, *) { return .label } else { return .black } }}