chore: import upstream snapshot with attribution

2026-07-13 12:22:33 +08:00
commit fc4fcbab58
1848 changed files with 472303 additions and 0 deletions
@@ -0,0 +1,96 @@
+import AppKit
+import CoreVideo
+import Observation
+import QuartzCore
+
+/// Minimal display link driver using NSScreen.displayLink on macOS 15+,
+/// and CVDisplayLink on macOS 14.
+/// Publishes ticks on the main thread at the requested frame rate.
+@MainActor
+@Observable
+final class DisplayLinkDriver {
+    // Published counter used to drive SwiftUI updates.
+    var tick: Int = 0
+    private var displayLink: CADisplayLink?
+    private var cvDisplayLink: CVDisplayLink?
+    private var targetInterval: CFTimeInterval = 1.0 / 60.0
+    private var lastTickTimestamp: CFTimeInterval = 0
+    private let onTick: (() -> Void)?
+
+    init(onTick: (() -> Void)? = nil) {
+        self.onTick = onTick
+    }
+
+    func start(fps: Double = 12) {
+        guard self.displayLink == nil, self.cvDisplayLink == nil else { return }
+        let clampedFps = max(fps, 1)
+        self.targetInterval = 1.0 / clampedFps
+        self.lastTickTimestamp = 0
+        if #available(macOS 15, *), let screen = NSScreen.main {
+            // NSScreen.displayLink is macOS 15+ only.
+            let displayLink = screen.displayLink(target: self, selector: #selector(self.step))
+            let rate = Float(clampedFps)
+            displayLink.preferredFrameRateRange = CAFrameRateRange(
+                minimum: rate,
+                maximum: rate,
+                preferred: rate)
+            displayLink.add(to: .main, forMode: .common)
+            self.displayLink = displayLink
+        } else {
+            self.startCVDisplayLink()
+        }
+    }
+
+    func stop() {
+        self.displayLink?.invalidate()
+        self.displayLink = nil
+        if let cvDisplayLink = self.cvDisplayLink {
+            CVDisplayLinkStop(cvDisplayLink)
+        }
+        self.cvDisplayLink = nil
+    }
+
+    @objc private func step(_: AnyObject) {
+        self.handleTick()
+    }
+
+    private func handleTick() {
+        let now = CACurrentMediaTime()
+        if self.lastTickTimestamp > 0, now - self.lastTickTimestamp < self.targetInterval {
+            return
+        }
+        self.lastTickTimestamp = now
+        // Safe on main runloop; drives SwiftUI updates.
+        self.tick &+= 1
+        self.onTick?()
+    }
+
+    private func startCVDisplayLink() {
+        var link: CVDisplayLink?
+        if CVDisplayLinkCreateWithActiveCGDisplays(&link) != kCVReturnSuccess {
+            return
+        }
+        guard let link else { return }
+        let callback: CVDisplayLinkOutputCallback = { _, _, _, _, _, userInfo in
+            guard let userInfo else { return kCVReturnSuccess }
+            let driver = Unmanaged<DisplayLinkDriver>.fromOpaque(userInfo).takeUnretainedValue()
+            driver.scheduleTick()
+            return kCVReturnSuccess
+        }
+        CVDisplayLinkSetOutputCallback(link, callback, Unmanaged.passUnretained(self).toOpaque())
+        CVDisplayLinkStart(link)
+        self.cvDisplayLink = link
+    }
+
+    private nonisolated func scheduleTick() {
+        Task { @MainActor [weak self] in
+            self?.handleTick()
+        }
+    }
+
+    deinit {
+        Task { @MainActor [weak self] in
+            self?.stop()
+        }
+    }
+}