macos: detect renderer health failures and show error view

src/apprt/embedded.zig

@@ -11,6 +11,7 @@ const Allocator = std.mem.Allocator;
 const objc = @import("objc");
 const apprt = @import("../apprt.zig");
 const input = @import("../input.zig");
+const renderer = @import("../renderer.zig");
 const terminal = @import("../terminal/main.zig");
 const CoreApp = @import("../App.zig");
 const CoreInspector = @import("../inspector/main.zig").Inspector;
@@ -123,6 +124,9 @@ pub const App = struct {
 
         /// Show a desktop notification to the user.
         show_desktop_notification: ?*const fn (SurfaceUD, [*:0]const u8, [*:0]const u8) void = null,
+
+        /// Called when the health of the renderer changes.
+        update_renderer_health: ?*const fn (SurfaceUD, renderer.Health) void = null,
     };
 
     /// Special values for the goto_tab callback.
@@ -960,6 +964,16 @@ pub const Surface = struct {
 
         func(self.opts.userdata, title, body);
     }
+
+    /// Update the health of the renderer.
+    pub fn updateRendererHealth(self: *const Surface, health: renderer.Health) void {
+        const func = self.app.opts.update_renderer_health orelse {
+            log.info("runtime embedder does not support update_renderer_health", .{});
+            return;
+        };
+
+        func(self.opts.userdata, health);
+    }
 };
 
 /// Inspector is the state required for the terminal inspector. A terminal

src/renderer.zig

@@ -55,7 +55,7 @@ pub const Renderer = switch (build_config.renderer) {
 /// The health status of a renderer. These must be shared across all
 /// renderers even if some states aren't reachable so that our API users
 /// can use the same enum for all renderers.
-pub const Health = enum(u8) {
+pub const Health = enum(c_int) {
     healthy = 0,
     unhealthy = 1,
 };

src/renderer/Metal.zig

@@ -896,7 +896,7 @@ fn bufferCompleted(
     const status = buffer.getProperty(mtl.MTLCommandBufferStatus, "status");
     const health: Health = switch (status) {
         .@"error" => .unhealthy,
-        else => .healthy,
+        else => .unhealthy,
     };
 
     // If our health value hasn't changed, then we do nothing. We don't