blinking cursor

src/App.zig

@@ -76,18 +76,12 @@ pub fn run(self: App) !void {
     defer embed.deinit(self.alloc);
     try embed.start();
 
-    // Notify the embedder to stop. We purposely do NOT wait for `join`
-    // here because handles with long timeouts may cause this to take a long
-    // time. We're exiting the app anyways if we're here so we let the OS
-    // clean up the threads.
-    defer embed.stop();
-
     // We need at least one handle in the event loop at all times so
     // that the loop doesn't spin 100% CPU.
     var timer = try libuv.Timer.init(self.alloc, self.loop);
-    defer timer.deinit(self.alloc);
+    errdefer timer.deinit(self.alloc);
     try timer.start((struct {
-        fn callback(_: libuv.Timer) void {}
+        fn callback(_: *libuv.Timer) void {}
     }).callback, 5000, 5000);
 
     while (!self.window.shouldClose()) {
@@ -101,7 +95,14 @@ pub fn run(self: App) !void {
         try embed.loopRun();
     }
 
-    // CLose our timer so that we can cleanly close the loop.
-    timer.close(null);
-    _ = try self.loop.run(.default);
+    // Close our timer so that we can cleanly close the loop.
+    timer.close((struct {
+        fn callback(t: *libuv.Timer) void {
+            const alloc = t.loop().getData(Allocator).?.*;
+            t.deinit(alloc);
+        }
+    }).callback);
+
+    embed.stop();
+    try embed.join();
 }

src/Grid.zig

@@ -10,7 +10,6 @@ const FontAtlas = @import("FontAtlas.zig");
 const Terminal = @import("terminal/Terminal.zig");
 const gl = @import("opengl.zig");
 const gb = @import("gb_math.zig");
-const libuv = @import("libuv/main.zig");
 
 const log = std.log.scoped(.grid);
 
@@ -35,8 +34,9 @@ texture: gl.Texture,
 /// The font atlas.
 font_atlas: FontAtlas,
 
-/// The timer for cursor blining.
-cursor_timer: libuv.Timer,
+/// Whether the cursor is visible or not. This is used to control cursor
+/// blinking.
+cursor_visible: bool,
 
 /// The raw structure that maps directly to the buffer sent to the vertex shader.
 const GPUCell = struct {
@@ -72,11 +72,7 @@ const GPUCell = struct {
     mode: u8,
 };
 
-pub fn init(alloc: Allocator, loop: libuv.Loop) !Grid {
-    // Setup the timer for our cursor.
-    var timer = try libuv.Timer.init(alloc, loop);
-    errdefer timer.deinit(alloc);
-
+pub fn init(alloc: Allocator) !Grid {
     // Initialize our font atlas. We will initially populate the
     // font atlas with all the visible ASCII characters since they are common.
     var atlas = try Atlas.init(alloc, 512);
@@ -214,17 +210,11 @@ pub fn init(alloc: Allocator, loop: libuv.Loop) !Grid {
         .vbo = vbo,
         .texture = tex,
         .font_atlas = font,
-        .cursor_timer = timer,
+        .cursor_visible = true,
     };
 }
 
 pub fn deinit(self: *Grid) void {
-    self.cursor_timer.close((struct {
-        fn callback(t: *libuv.Timer) void {
-            const alloc = t.loop().getData(Allocator).?;
-            t.deinit(alloc.*);
-        }
-    }).callback);
     self.font_atlas.atlas.deinit(self.alloc);
     self.font_atlas.deinit(self.alloc);
     self.texture.destroy();
@@ -303,6 +293,7 @@ pub fn updateCells(self: *Grid, term: Terminal) !void {
     }
 
     // Draw the cursor
+    if (self.cursor_visible) {
         self.cells.appendAssumeCapacity(.{
             .mode = 1,
             .grid_col = @intCast(u16, term.cursor.x),
@@ -316,6 +307,7 @@ pub fn updateCells(self: *Grid, term: Terminal) !void {
             .bg_b = 0xFF,
             .bg_a = 255,
         });
+    }
 }
 
 /// Set the screen size for rendering. This will update the projection

src/Window.zig

@@ -35,6 +35,9 @@ pty: Pty,
 /// a renderer.
 terminal: Terminal,
 
+/// Timer that blinks the cursor.
+cursor_timer: libuv.Timer,
+
 /// Create a new window. This allocates and returns a pointer because we
 /// need a stable pointer for user data callbacks. Therefore, a stack-only
 /// initialization is not currently possible.
@@ -78,7 +81,7 @@ pub fn create(alloc: Allocator, loop: libuv.Loop) !*Window {
 
     // Create our terminal grid with the initial window size
     const window_size = try window.getSize();
-    var grid = try Grid.init(alloc, loop);
+    var grid = try Grid.init(alloc);
     try grid.setScreenSize(.{ .width = window_size.width, .height = window_size.height });
 
     // Create our pty
@@ -95,12 +98,20 @@ pub fn create(alloc: Allocator, loop: libuv.Loop) !*Window {
     errdefer term.deinit(alloc);
     try term.append(alloc, "> ");
 
+    // Setup a timer for blinking the cursor
+    var timer = try libuv.Timer.init(alloc, loop);
+    errdefer timer.deinit(alloc);
+    errdefer timer.close(null);
+    timer.setData(self);
+    try timer.start(cursorTimerCallback, 800, 800);
+
     self.* = .{
         .alloc = alloc,
         .window = window,
         .grid = grid,
         .pty = pty,
         .terminal = term,
+        .cursor_timer = timer,
     };
 
     // Setup our callbacks and user data
@@ -113,6 +124,12 @@ pub fn create(alloc: Allocator, loop: libuv.Loop) !*Window {
 }
 
 pub fn destroy(self: *Window) void {
+    self.cursor_timer.close((struct {
+        fn callback(t: *libuv.Timer) void {
+            const alloc = t.loop().getData(Allocator).?.*;
+            t.deinit(alloc);
+        }
+    }).callback);
     self.terminal.deinit(self.alloc);
     self.pty.deinit();
     self.grid.deinit();
@@ -195,3 +212,9 @@ fn keyCallback(
         win.grid.updateCells(win.terminal) catch unreachable;
     }
 }
+
+fn cursorTimerCallback(t: *libuv.Timer) void {
+    const win = t.getData(Window) orelse return;
+    win.grid.cursor_visible = !win.grid.cursor_visible;
+    win.grid.updateCells(win.terminal) catch unreachable;
+}

src/libuv/Timer.zig

@@ -32,14 +32,14 @@ pub fn deinit(self: *Timer, alloc: Allocator) void {
 /// and then repeatedly after repeat milliseconds.
 pub fn start(
     self: Timer,
-    comptime cb: fn (Timer) void,
+    comptime cb: fn (*Timer) void,
     timeout: u64,
     repeat: u64,
 ) !void {
     const Wrapper = struct {
         pub fn callback(handle: [*c]c.uv_timer_t) callconv(.C) void {
-            const newSelf: Timer = .{ .handle = handle };
-            @call(.{ .modifier = .always_inline }, cb, .{newSelf});
+            var newSelf: Timer = .{ .handle = handle };
+            @call(.{ .modifier = .always_inline }, cb, .{&newSelf});
         }
     };
 
@@ -65,7 +65,7 @@ test "Timer" {
     var called: bool = false;
     timer.setData(&called);
     try timer.start((struct {
-        fn callback(t: Timer) void {
+        fn callback(t: *Timer) void {
             t.getData(bool).?.* = true;
             t.close(null);
         }

src/libuv/tests.zig

@@ -16,7 +16,7 @@ test "Async: cancel timer" {
 
     // Start a timer with a long timeout. This will block our loop.
     try timer.start((struct {
-        fn callback(_: libuv.Timer) void {}
+        fn callback(_: *libuv.Timer) void {}
     }).callback, 5000, 5000);
 
     var async_handle = try libuv.Async.init(testing.allocator, loop, (struct {