macOS: Fix rendering getting stuck on some machines after sleep/screensaver

This is caused, as far as I can tell, by CVDisplayLink getting stuck.
Apple apparently are incapable of writing a simple timer robustly.
So if it remains stuck after a second delete and recreate it to force it
to restart.

Fixes #2016

docs/changelog.rst

@@ -37,6 +37,9 @@ To update |kitty|, :doc:`follow the instructions <binary>`.
 - macOS: When the Apple Color Emoji font lacks an emoji glyph search for it in other
   installed fonts (:iss:`3591`)
 
+- macOS: Fix rendering getting stuck on some machines after sleep/screensaver
+  (:iss:`2016`)
+
 - Add a few more special commandline arguments for the launch command. Now all
   ``KITTY_PIPE_DATA`` is also available via command line argument substitution
   (:iss:`3593`)

glfw/cocoa_monitor.m

@@ -316,6 +316,7 @@ void _glfwClearDisplayLinks() {
             CVDisplayLinkRelease(_glfw.ns.displayLinks.entries[i].displayLink);
             _glfw.ns.displayLinks.entries[i].displayLink = nil;
             _glfw.ns.displayLinks.entries[i].lastRenderFrameRequestedAt = 0;
+            _glfw.ns.displayLinks.entries[i].first_unserviced_render_frame_request_at = 0;
         }
     }
     _glfw.ns.displayLinks.count = 0;
@@ -333,7 +334,14 @@ static CVReturn displayLinkCallback(
     return kCVReturnSuccess;
 }
 
-static inline void createDisplayLink(CGDirectDisplayID displayID) {
+void
+_glfw_create_cv_display_link(_GLFWDisplayLinkNS *entry) {
+    CVDisplayLinkCreateWithCGDisplay(entry->displayID, &entry->displayLink);
+    CVDisplayLinkSetOutputCallback(entry->displayLink, &displayLinkCallback, (void*)(uintptr_t)entry->displayID);
+}
+
+static void
+createDisplayLink(CGDirectDisplayID displayID) {
     if (_glfw.ns.displayLinks.count >= sizeof(_glfw.ns.displayLinks.entries)/sizeof(_glfw.ns.displayLinks.entries[0]) - 1) return;
     for (size_t i = 0; i < _glfw.ns.displayLinks.count; i++) {
         if (_glfw.ns.displayLinks.entries[i].displayID == displayID) return;
@@ -341,8 +349,7 @@ static inline void createDisplayLink(CGDirectDisplayID displayID) {
     _GLFWDisplayLinkNS *entry = &_glfw.ns.displayLinks.entries[_glfw.ns.displayLinks.count++];
     memset(entry, 0, sizeof(_GLFWDisplayLinkNS));
     entry->displayID = displayID;
-    CVDisplayLinkCreateWithCGDisplay(displayID, &entry->displayLink);
-    CVDisplayLinkSetOutputCallback(entry->displayLink, &displayLinkCallback, (void*)(uintptr_t)displayID);
+    _glfw_create_cv_display_link(entry);
 }
 
 // Poll for changes in the set of connected monitors

glfw/cocoa_platform.h

@@ -158,7 +158,7 @@ typedef struct _GLFWDisplayLinkNS
 {
     CVDisplayLinkRef displayLink;
     CGDirectDisplayID displayID;
-    monotonic_t lastRenderFrameRequestedAt;
+    monotonic_t lastRenderFrameRequestedAt, first_unserviced_render_frame_request_at;
 } _GLFWDisplayLinkNS;
 
 // Cocoa-specific global data
@@ -246,3 +246,4 @@ void _glfwDispatchTickCallback(void);
 void _glfwDispatchRenderFrame(CGDirectDisplayID);
 void _glfwShutdownCVDisplayLink(unsigned long long, void*);
 void _glfwCocoaPostEmptyEvent(void);
+void _glfw_create_cv_display_link(_GLFWDisplayLinkNS *entry);

glfw/cocoa_window.m

@@ -317,6 +317,7 @@ _glfwShutdownCVDisplayLink(unsigned long long timer_id UNUSED, void *user_data U
         _GLFWDisplayLinkNS *dl = &_glfw.ns.displayLinks.entries[i];
         if (dl->displayLink) CVDisplayLinkStop(dl->displayLink);
         dl->lastRenderFrameRequestedAt = 0;
+        dl->first_unserviced_render_frame_request_at = 0;
     }
 }
 
@@ -340,10 +341,22 @@ requestRenderFrame(_GLFWwindow *w, GLFWcocoarenderframefun callback) {
         _GLFWDisplayLinkNS *dl = &_glfw.ns.displayLinks.entries[i];
         if (dl->displayID == displayID) {
             dl->lastRenderFrameRequestedAt = now;
+            if (!dl->first_unserviced_render_frame_request_at) dl->first_unserviced_render_frame_request_at = now;
             if (!CVDisplayLinkIsRunning(dl->displayLink)) CVDisplayLinkStart(dl->displayLink);
+            else if (now - dl->first_unserviced_render_frame_request_at > s_to_monotonic_t(1ll)) {
+                // display link is stuck need to recreate it because Apple cant even
+                // get a simple timer right
+                CVDisplayLinkRelease(dl->displayLink); dl->displayLink = nil;
+                dl->first_unserviced_render_frame_request_at = now;
+                _glfw_create_cv_display_link(dl);
+                _glfwInputError(GLFW_PLATFORM_ERROR,
+                    "CVDisplayLink stuck possibly because of sleep/screensaver + Apple's incompetence, recreating.");
+                if (!CVDisplayLinkIsRunning(dl->displayLink)) CVDisplayLinkStart(dl->displayLink);
+            }
         } else if (dl->displayLink && dl->lastRenderFrameRequestedAt && now - dl->lastRenderFrameRequestedAt >= DISPLAY_LINK_SHUTDOWN_CHECK_INTERVAL) {
             CVDisplayLinkStop(dl->displayLink);
             dl->lastRenderFrameRequestedAt = 0;
+            dl->first_unserviced_render_frame_request_at = 0;
         }
     }
 }
@@ -2141,6 +2154,12 @@ _glfwDispatchRenderFrame(CGDirectDisplayID displayID) {
         }
         w = w->next;
     }
+    for (size_t i = 0; i < _glfw.ns.displayLinks.count; i++) {
+        _GLFWDisplayLinkNS *dl = &_glfw.ns.displayLinks.entries[i];
+        if (dl->displayID == displayID) {
+            dl->first_unserviced_render_frame_request_at = 0;
+        }
+    }
 }
 
 void _glfwPlatformGetCursorPos(_GLFWwindow* window, double* xpos, double* ypos)