webdriver: Implement support for simple dialogs (#37913)

Implement webdriver user prompt: accept alert, dismiss alert, get alert
text.

Tests:
https://github.com/longvatrong111/servo/actions/runs/16175408035
https://github.com/longvatrong111/servo/actions/runs/16175409545

Signed-off-by: batu_hoang <longvatrong111@gmail.com>

components/webdriver_server/lib.rs

@@ -8,6 +8,7 @@
 
 mod actions;
 mod capabilities;
+mod user_prompt;
 
 use std::borrow::ToOwned;
 use std::cell::{Cell, LazyCell, RefCell};
@@ -515,6 +516,11 @@ impl Handler {
         Ok(())
     }
 
+    // This function is called only if session and webview are verified.
+    fn verified_webview_id(&self) -> WebViewId {
+        self.session().unwrap().webview_id
+    }
+
     fn focus_webview_id(&self) -> WebDriverResult<WebViewId> {
         let (sender, receiver) = ipc::channel().unwrap();
         self.send_message_to_embedder(WebDriverCommandMsg::GetFocusedWebView(sender.clone()))?;
@@ -782,7 +788,19 @@ impl Handler {
         debug!("waiting for load");
         let timeout = self.session()?.load_timeout;
         let result = select! {
-            recv(self.load_status_receiver) -> _ => Ok(WebDriverResponse::Void),
+            recv(self.load_status_receiver) -> res => {
+                    match res {
+                    Ok(WebDriverLoadStatus::Blocked) => {
+                        Err(WebDriverError::new(
+                            ErrorStatus::UnexpectedAlertOpen,
+                            "Load is blocked",
+                        ))
+                    }
+                    _ => {
+                        Ok(WebDriverResponse::Void)
+                    }
+                }
+            },
             recv(after(Duration::from_millis(timeout))) -> _ => Err(
                 WebDriverError::new(ErrorStatus::Timeout, "Load timed out")
             ),
@@ -1605,15 +1623,6 @@ impl Handler {
         }
     }
 
-    // https://w3c.github.io/webdriver/#dismiss-alert
-    fn handle_dismiss_alert(&mut self) -> WebDriverResult<WebDriverResponse> {
-        // Step 1. If session's current top-level browsing context is no longer open,
-        // return error with error code no such window.
-        self.verify_top_level_browsing_context_is_open(self.session()?.webview_id)?;
-        // Since user prompts are not yet implement this will always succeed
-        Ok(WebDriverResponse::Void)
-    }
-
     fn handle_get_timeouts(&mut self) -> WebDriverResult<WebDriverResponse> {
         let session = self
             .session
@@ -2231,6 +2240,8 @@ impl WebDriverHandler<ServoExtensionRoute> for Handler {
             },
             WebDriverCommand::ElementClick(ref element) => self.handle_element_click(element),
             WebDriverCommand::DismissAlert => self.handle_dismiss_alert(),
+            WebDriverCommand::AcceptAlert => self.handle_accept_alert(),
+            WebDriverCommand::GetAlertText => self.handle_get_alert_text(),
             WebDriverCommand::DeleteCookies => self.handle_delete_cookies(),
             WebDriverCommand::DeleteCookie(name) => self.handle_delete_cookie(name),
             WebDriverCommand::GetTimeouts => self.handle_get_timeouts(),

components/webdriver_server/user_prompt.rs

@@ -0,0 +1,93 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use embedder_traits::{WebDriverCommandMsg, WebDriverUserPromptAction};
+use ipc_channel::ipc;
+use webdriver::error::{ErrorStatus, WebDriverError, WebDriverResult};
+use webdriver::response::{ValueResponse, WebDriverResponse};
+
+use crate::{Handler, wait_for_script_response};
+
+impl Handler {
+    /// <https://w3c.github.io/webdriver/#dismiss-alert>
+    pub(crate) fn handle_dismiss_alert(&mut self) -> WebDriverResult<WebDriverResponse> {
+        // Step 1. If session's current top-level browsing context is no longer open,
+        // return error with error code no such window.
+        self.verify_top_level_browsing_context_is_open(self.session()?.webview_id)?;
+
+        // Step 3. Dismiss the current user prompt.
+        let (sender, receiver) = ipc::channel().unwrap();
+        self.send_message_to_embedder(WebDriverCommandMsg::HandleUserPrompt(
+            self.verified_webview_id(),
+            WebDriverUserPromptAction::Dismiss,
+            sender,
+        ))?;
+
+        match wait_for_script_response(receiver)? {
+            // Step 2. If the current user prompt is null, return error with error code no such alert.
+            Err(()) => Err(WebDriverError::new(
+                ErrorStatus::NoSuchAlert,
+                "No user prompt is currently active.",
+            )),
+            // Step 4. Return success with data null.
+            Ok(()) => Ok(WebDriverResponse::Void),
+        }
+    }
+
+    /// <https://w3c.github.io/webdriver/#accept-alert>
+    pub(crate) fn handle_accept_alert(&mut self) -> WebDriverResult<WebDriverResponse> {
+        // Step 1. If session's current top-level browsing context is no longer open,
+        // return error with error code no such window.
+        self.verify_top_level_browsing_context_is_open(self.session()?.webview_id)?;
+
+        // Step 3. Accept the current user prompt.
+        let (sender, receiver) = ipc::channel().unwrap();
+        self.send_message_to_embedder(WebDriverCommandMsg::HandleUserPrompt(
+            self.verified_webview_id(),
+            WebDriverUserPromptAction::Accept,
+            sender,
+        ))?;
+
+        match wait_for_script_response(receiver)? {
+            // Step 2. If the current user prompt is null, return error with error code no such alert.
+            Err(()) => Err(WebDriverError::new(
+                ErrorStatus::NoSuchAlert,
+                "No user prompt is currently active.",
+            )),
+            // Step 4. Return success with data null.
+            Ok(()) => Ok(WebDriverResponse::Void),
+        }
+    }
+
+    pub(crate) fn handle_get_alert_text(&mut self) -> WebDriverResult<WebDriverResponse> {
+        // Step 1. If session's current top-level browsing context is no longer open,
+        // return error with error code no such window.
+        self.verify_top_level_browsing_context_is_open(self.session()?.webview_id)?;
+
+        let (sender, receiver) = ipc::channel().unwrap();
+        self.send_message_to_embedder(WebDriverCommandMsg::GetAlertText(
+            self.verified_webview_id(),
+            sender,
+        ))?;
+
+        match wait_for_script_response(receiver)? {
+            // Step 2. If the current user prompt is null, return error with error code no such alert.
+            Err(()) => Err(WebDriverError::new(
+                ErrorStatus::NoSuchAlert,
+                "No user prompt is currently active.",
+            )),
+            // Step 3. Let message be the text message associated with the current user prompt
+            // or otherwise be null
+            // Step 4. Return success with data message.
+            Ok(message) => Ok(WebDriverResponse::Generic(ValueResponse(
+                serde_json::to_value(message).map_err(|e| {
+                    WebDriverError::new(
+                        ErrorStatus::UnknownError,
+                        format!("Failed to serialize alert text: {}", e),
+                    )
+                })?,
+            ))),
+        }
+    }
+}