From 569c5c7ce0ca22a27706bb72f315c44b12a188a5 Mon Sep 17 00:00:00 2001
From: Euclid Ye <yezhizhenjiakang@gmail.com>
Date: Wed, 30 Apr 2025 10:59:02 +0800
Subject: [PATCH] Synchronize `WebdriverScriptEvent` with pending input events

Signed-off-by: Euclid Ye <yezhizhenjiakang@gmail.com>
Co-authored-by: batu_hoang <longvatrong111@gmail.com>
---
 components/script/script_thread.rs | 57 +++++++++++++++++++++++++-----
 1 file changed, 48 insertions(+), 9 deletions(-)

diff --git a/components/script/script_thread.rs b/components/script/script_thread.rs
index 7241c115a2a..092552928a0 100644
--- a/components/script/script_thread.rs
+++ b/components/script/script_thread.rs
@@ -335,6 +335,14 @@ pub struct ScriptThread {
     /// The screen coordinates where the primary mouse button was pressed.
     #[no_trace]
     relative_mouse_down_point: Cell<Point2D<f32, DevicePixel>>,
+
+    #[no_trace]
+    pending_webdriver_script_events: DomRefCell<HashMap<PipelineId, Vec<WebdriverScriptEvent>>>,
+}
+
+struct WebdriverScriptEvent {
+    pub msg: WebDriverScriptCommand,
+    pub can_gc: CanGc,
 }
 
 struct BHMExitSignal {
@@ -954,6 +962,7 @@ impl ScriptThread {
             inherited_secure_context: state.inherited_secure_context,
             layout_factory,
             relative_mouse_down_point: Cell::new(Point2D::zero()),
+            pending_webdriver_script_events: Default::default(),
         }
     }
 
@@ -1060,6 +1069,30 @@ impl ScriptThread {
         }
     }
 
+    fn process_pending_webdriver_script_events(&self, pipeline_id: PipelineId) {
+        if let Some(events) = self
+            .pending_webdriver_script_events
+            .borrow_mut()
+            .remove(&pipeline_id)
+        {
+            for WebdriverScriptEvent { msg, can_gc } in events {
+                match msg {
+                    WebDriverScriptCommand::ExecuteScript(script, reply) => {
+                        let window = self.documents.borrow().find_window(pipeline_id);
+                        webdriver_handlers::handle_execute_script(window, script, reply, can_gc);
+                    },
+                    WebDriverScriptCommand::ExecuteAsyncScript(script, reply) => {
+                        let window = self.documents.borrow().find_window(pipeline_id);
+                        webdriver_handlers::handle_execute_async_script(
+                            window, script, reply, can_gc,
+                        );
+                    },
+                    _ => (),
+                }
+            }
+        }
+    }
+
     /// Process compositor events as part of a "update the rendering task".
     fn process_pending_input_events(&self, pipeline_id: PipelineId, can_gc: CanGc) {
         let Some(document) = self.documents.borrow().find_document(pipeline_id) else {
@@ -1272,6 +1305,9 @@ impl ScriptThread {
             #[cfg(feature = "webgpu")]
             document.update_rendering_of_webgpu_canvases();
 
+            // after entering realm, process pending webdriver script event
+            self.process_pending_webdriver_script_events(*pipeline_id);
+
             // > Step 22: For each doc of docs, update the rendering or user interface of
             // > doc and its node navigable to reflect the current state.
             let window = document.window();
@@ -1283,6 +1319,10 @@ impl ScriptThread {
             // https://drafts.csswg.org/css-position-4/#process-top-layer-removals.
         }
 
+        // TODO: remaining documents requested are non-existent
+        // For each left in self.pending_webdriver_script_events
+        // reply.send(Err(WebDriverJSError::BrowsingContextNotFound)).unwrap();
+
         // Perform a microtask checkpoint as the specifications says that *update the rendering*
         // should be run in a task and a microtask checkpoint is always done when running tasks.
         self.perform_a_microtask_checkpoint(can_gc);
@@ -2088,15 +2128,14 @@ impl ScriptThread {
         // `self.documents`, which would conflict with the immutable borrow of it that
         // occurs for the rest of the messages
         match msg {
-            WebDriverScriptCommand::ExecuteScript(script, reply) => {
-                let window = self.documents.borrow().find_window(pipeline_id);
-                return webdriver_handlers::handle_execute_script(window, script, reply, can_gc);
-            },
-            WebDriverScriptCommand::ExecuteAsyncScript(script, reply) => {
-                let window = self.documents.borrow().find_window(pipeline_id);
-                return webdriver_handlers::handle_execute_async_script(
-                    window, script, reply, can_gc,
-                );
+            WebDriverScriptCommand::ExecuteScript(..) |
+            WebDriverScriptCommand::ExecuteAsyncScript(..) => {
+                self.pending_webdriver_script_events
+                    .borrow_mut()
+                    .entry(pipeline_id)
+                    .or_default()
+                    .push(WebdriverScriptEvent { msg, can_gc });
+                return;
             },
             _ => (),
         }