Initial OpenScreen import

electron/native/screencapturekit/Sources/OpenScreenMacOSCursorHelper/main.swift

@@ -0,0 +1,268 @@
+import AppKit
+import ApplicationServices
+import Foundation
+
+struct CursorHelperRequest: Decodable {
+	let sampleIntervalMs: Int?
+}
+
+final class MouseButtonTracker {
+	private let lock = NSLock()
+	private var leftDownCount = 0
+	private var leftUpCount = 0
+	private var eventTap: CFMachPort?
+	private var runLoopSource: CFRunLoopSource?
+
+	struct Events {
+		let leftDownCount: Int
+		let leftUpCount: Int
+	}
+
+	func start() -> Bool {
+		let mask =
+			(1 << CGEventType.leftMouseDown.rawValue) |
+			(1 << CGEventType.leftMouseUp.rawValue)
+		guard let tap = CGEvent.tapCreate(
+			tap: .cgSessionEventTap,
+			place: .headInsertEventTap,
+			options: .listenOnly,
+			eventsOfInterest: CGEventMask(mask),
+			callback: { _, type, event, userInfo in
+				if let userInfo {
+					let tracker = Unmanaged<MouseButtonTracker>.fromOpaque(userInfo).takeUnretainedValue()
+					tracker.record(type)
+				}
+				return Unmanaged.passUnretained(event)
+			},
+			userInfo: UnsafeMutableRawPointer(Unmanaged.passUnretained(self).toOpaque())
+		) else {
+			return false
+		}
+
+		guard let source = CFMachPortCreateRunLoopSource(kCFAllocatorDefault, tap, 0) else {
+			return false
+		}
+
+		eventTap = tap
+		runLoopSource = source
+		CFRunLoopAddSource(CFRunLoopGetCurrent(), source, .commonModes)
+		CGEvent.tapEnable(tap: tap, enable: true)
+		return true
+	}
+
+	func pump() {
+		CFRunLoopRunInMode(.defaultMode, 0.001, false)
+	}
+
+	func consume() -> Events {
+		lock.lock()
+		defer { lock.unlock() }
+		let events = Events(leftDownCount: leftDownCount, leftUpCount: leftUpCount)
+		leftDownCount = 0
+		leftUpCount = 0
+		return events
+	}
+
+	private func record(_ type: CGEventType) {
+		lock.lock()
+		defer { lock.unlock() }
+		if type == .tapDisabledByTimeout || type == .tapDisabledByUserInput {
+			reenableTap()
+			return
+		}
+		if type == .leftMouseDown {
+			leftDownCount += 1
+		} else if type == .leftMouseUp {
+			leftUpCount += 1
+		}
+	}
+
+	private func reenableTap() {
+		if let eventTap {
+			CGEvent.tapEnable(tap: eventTap, enable: true)
+		}
+	}
+}
+
+func emit(_ fields: [String: Any?]) {
+	let compacted = fields.compactMapValues { $0 }
+	if let data = try? JSONSerialization.data(withJSONObject: compacted, options: []),
+		let line = String(data: data, encoding: .utf8)
+	{
+		print(line)
+		fflush(stdout)
+	}
+}
+
+func stringAttribute(_ element: AXUIElement, _ attribute: String) -> String? {
+	var value: CFTypeRef?
+	let result = AXUIElementCopyAttributeValue(element, attribute as CFString, &value)
+	guard result == .success else {
+		return nil
+	}
+
+	return value as? String
+}
+
+func parentElement(_ element: AXUIElement) -> AXUIElement? {
+	var value: CFTypeRef?
+	let result = AXUIElementCopyAttributeValue(element, kAXParentAttribute as CFString, &value)
+	guard result == .success else {
+		return nil
+	}
+
+	guard CFGetTypeID(value) == AXUIElementGetTypeID() else {
+		return nil
+	}
+
+	return (value as! AXUIElement)
+}
+
+func roleDescription(_ element: AXUIElement) -> String? {
+	var value: CFTypeRef?
+	let result = AXUIElementCopyAttributeValue(element, kAXRoleDescriptionAttribute as CFString, &value)
+	guard result == .success else {
+		return nil
+	}
+
+	return value as? String
+}
+
+func actionNames(_ element: AXUIElement) -> [String] {
+	var value: CFArray?
+	let result = AXUIElementCopyActionNames(element, &value)
+	guard result == .success, let value else {
+		return []
+	}
+
+	return (value as NSArray).compactMap { $0 as? String }
+}
+func isTextInputRole(_ role: String?) -> Bool {
+	role == "AXTextField" ||
+		role == "AXTextArea" ||
+		role == "AXTextView" ||
+		role == "AXComboBox"
+}
+
+func isPointerRole(_ role: String?, _ subrole: String?, _ description: String?) -> Bool {
+	if role == "AXLink" ||
+		subrole?.localizedCaseInsensitiveContains("link") == true ||
+		description?.contains("link") == true
+	{
+		return true
+	}
+
+	return role == "AXButton" ||
+		role == "AXMenuButton" ||
+		role == "AXPopUpButton" ||
+		role == "AXCheckBox" ||
+		role == "AXRadioButton" ||
+		role == "AXSwitch" ||
+		role == "AXDisclosureTriangle" ||
+		role == "AXTab" ||
+		role == "AXMenuItem"
+}
+
+func cursorTypeForElement(_ element: AXUIElement) -> String? {
+	var current: AXUIElement? = element
+
+	for _ in 0..<5 {
+		guard let element = current else {
+			break
+		}
+
+		let role = stringAttribute(element, kAXRoleAttribute)
+		let subrole = stringAttribute(element, kAXSubroleAttribute)
+		let description = roleDescription(element)?.lowercased()
+
+		if isTextInputRole(role) {
+			return "text"
+		}
+
+		if isPointerRole(role, subrole, description) {
+			return "pointer"
+		}
+
+		current = parentElement(element)
+	}
+
+	return nil
+}
+
+func accessibilityPointForMouse() -> CGPoint {
+	let mouse = NSEvent.mouseLocation
+	let primaryHeight = NSScreen.screens.first?.frame.height ?? NSScreen.main?.frame.height ?? 0
+	return CGPoint(x: mouse.x, y: primaryHeight - mouse.y)
+}
+
+func currentCursorType() -> String? {
+	guard AXIsProcessTrusted() else {
+		return nil
+	}
+
+	let point = accessibilityPointForMouse()
+	let systemWide = AXUIElementCreateSystemWide()
+	var element: AXUIElement?
+	let result = AXUIElementCopyElementAtPosition(
+		systemWide,
+		Float(point.x),
+		Float(point.y),
+		&element
+	)
+
+	guard result == .success, let element else {
+		return "arrow"
+	}
+
+	return cursorTypeForElement(element) ?? "arrow"
+}
+
+func timestampMs() -> Int {
+	Int(Date().timeIntervalSince1970 * 1000)
+}
+
+func leftButtonDown() -> Bool {
+	CGEventSource.buttonState(.hidSystemState, button: .left)
+}
+
+func requestAccessibilityTrust() -> Bool {
+	let options = [
+		kAXTrustedCheckOptionPrompt.takeUnretainedValue() as String: true
+	] as CFDictionary
+	return AXIsProcessTrustedWithOptions(options)
+}
+
+let request: CursorHelperRequest
+if CommandLine.arguments.count >= 2,
+	let data = CommandLine.arguments[1].data(using: .utf8),
+	let decoded = try? JSONDecoder().decode(CursorHelperRequest.self, from: data)
+{
+	request = decoded
+} else {
+	request = CursorHelperRequest(sampleIntervalMs: nil)
+}
+
+let intervalMs = max(8, request.sampleIntervalMs ?? 33)
+let accessibilityTrusted = requestAccessibilityTrust()
+let mouseTracker = MouseButtonTracker()
+let mouseTapReady = mouseTracker.start()
+emit([
+	"type": "ready",
+	"timestampMs": timestampMs(),
+	"accessibilityTrusted": accessibilityTrusted,
+	"mouseTapReady": mouseTapReady,
+])
+
+while true {
+	mouseTracker.pump()
+	let mouseEvents = mouseTracker.consume()
+	emit([
+		"type": "sample",
+		"timestampMs": timestampMs(),
+		"cursorType": currentCursorType(),
+		"leftButtonDown": leftButtonDown(),
+		"leftButtonPressed": mouseEvents.leftDownCount > 0,
+		"leftButtonReleased": mouseEvents.leftUpCount > 0,
+	])
+	Thread.sleep(forTimeInterval: Double(intervalMs) / 1000.0)
+}