From 44a76e59f98690cb3224a6c36e51ef718203390a Mon Sep 17 00:00:00 2001
From: Pierre Tachoire <pierre@lightpanda.io>
Date: Wed, 2 Jul 2025 13:16:20 -0700
Subject: [PATCH] run pumpmessageloop in its own loop

---
 src/browser/browser.zig |  4 ++++
 src/browser/page.zig    | 14 ++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/src/browser/browser.zig b/src/browser/browser.zig
index 623df886..d132a860 100644
--- a/src/browser/browser.zig
+++ b/src/browser/browser.zig
@@ -98,6 +98,10 @@ pub const Browser = struct {
 
     pub fn runMicrotasks(self: *const Browser) void {
         self.env.runMicrotasks();
+    }
+
+    pub fn runMessageLoop(self: *const Browser) void {
+        log.debug(.browser, "pumpMessageLoop", .{});
         while (self.env.pumpMessageLoop()) {
             log.debug(.browser, "pumpMessageLoop", .{});
         }
diff --git a/src/browser/page.zig b/src/browser/page.zig
index e8f92216..fd750b3d 100644
--- a/src/browser/page.zig
+++ b/src/browser/page.zig
@@ -78,7 +78,10 @@ pub const Page = struct {
 
     renderer: Renderer,
 
+    // run v8 micro tasks
     microtask_node: Loop.CallbackNode,
+    // run v8 pump message loop and idle tasks
+    messageloop_node: Loop.CallbackNode,
 
     keydown_event_node: parser.EventNode,
     window_clicked_event_node: parser.EventNode,
@@ -106,6 +109,7 @@ pub const Page = struct {
             .state_pool = &browser.state_pool,
             .cookie_jar = &session.cookie_jar,
             .microtask_node = .{ .func = microtaskCallback },
+            .messageloop_node = .{ .func = messageLoopCallback },
             .keydown_event_node = .{ .func = keydownCallback },
             .window_clicked_event_node = .{ .func = windowClicked },
             .request_factory = browser.http_client.requestFactory(.{
@@ -119,6 +123,10 @@ pub const Page = struct {
         try polyfill.load(self.arena, self.main_context);
 
         _ = try session.browser.app.loop.timeout(1 * std.time.ns_per_ms, &self.microtask_node);
+        // message loop must run only non-test env
+        if (comptime !builtin.is_test) {
+            _ = try session.browser.app.loop.timeout(1 * std.time.ns_per_ms, &self.messageloop_node);
+        }
     }
 
     fn microtaskCallback(node: *Loop.CallbackNode, repeat_delay: *?u63) void {
@@ -127,6 +135,12 @@ pub const Page = struct {
         repeat_delay.* = 1 * std.time.ns_per_ms;
     }
 
+    fn messageLoopCallback(node: *Loop.CallbackNode, repeat_delay: *?u63) void {
+        const self: *Page = @fieldParentPtr("messageloop_node", node);
+        self.session.browser.runMessageLoop();
+        repeat_delay.* = 100 * std.time.ns_per_ms;
+    }
+
     // dump writes the page content into the given file.
     pub fn dump(self: *const Page, out: std.fs.File) !void {
         if (self.raw_data) |raw_data| {