Auto merge of #23171 - hundredeir:find_elem_elems, r=jdm

add webdriver command "Find elements from Element"

---
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors

<!-- Either: -->
- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because ___

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components/script/script_thread.rs

@@ -1884,6 +1884,15 @@ impl ScriptThread {
                     reply,
                 )
             },
+            WebDriverScriptCommand::FindElementElementsCSS(selector, element_id, reply) => {
+                webdriver_handlers::handle_find_element_elements_css(
+                    &*documents,
+                    pipeline_id,
+                    element_id,
+                    selector,
+                    reply,
+                )
+            },
             WebDriverScriptCommand::FocusElement(element_id, reply) => {
                 webdriver_handlers::handle_focus_element(
                     &*documents,

components/script/webdriver_handlers.rs

@@ -220,6 +220,28 @@ pub fn handle_find_element_element_css(
     reply.send(node_id).unwrap();
 }
 
+pub fn handle_find_element_elements_css(
+    documents: &Documents,
+    pipeline: PipelineId,
+    element_id: String,
+    selector: String,
+    reply: IpcSender<Result<Option<String>, ()>>,
+) {
+    let node_ids = find_node_by_unique_id(documents, pipeline, element_id)
+        .ok_or(())
+        .and_then(|node| {
+            node.query_selector_all(DOMString::from(selector))
+                .map_err(|_| ())
+        })
+        .map(|nodes| {
+            nodes
+                .iter()
+                .map(|x| Some(x.upcast::<Node>().unique_id()))
+                .collect()
+        });
+    reply.send(node_ids).unwrap();
+}
+
 pub fn handle_focus_element(
     documents: &Documents,
     pipeline: PipelineId,

components/script_traits/webdriver_msg.rs

@@ -27,6 +27,7 @@ pub enum WebDriverScriptCommand {
     FindElementCSS(String, IpcSender<Result<Option<String>, ()>>),
     FindElementsCSS(String, IpcSender<Result<Vec<String>, ()>>),
     FindElementElementCSS(String, String, IpcSender<Result<Option<String>, ()>>),
+    FindElementElementsCSS(String, String, IpcSender<Result<Option<String>, ()>>),
     FocusElement(String, IpcSender<Result<(), ()>>),
     GetActiveElement(IpcSender<Option<String>>),
     GetCookie(String, IpcSender<Vec<Serde<Cookie<'static>>>>),

components/webdriver_server/lib.rs

@@ -803,6 +803,44 @@ impl Handler {
         }
     }
 
+    // https://w3c.github.io/webdriver/#find-elements-from-element
+    fn handle_find_elements_from_element(
+        &self,
+        element: &WebElement,
+        parameters: &LocatorParameters,
+    ) -> WebDriverResult<WebDriverResponse> {
+        if parameters.using != LocatorStrategy::CSSSelector {
+            return Err(WebDriverError::new(
+                ErrorStatus::UnsupportedOperation,
+                "Unsupported locator strategy",
+            ));
+        }
+
+        let (sender, receiver) = ipc::channel().unwrap();
+        let cmd = WebDriverScriptCommand::FindElementElementsCSS(
+            parameters.value.clone(),
+            element.id.clone(),
+            sender,
+        );
+
+        self.browsing_context_script_command(cmd)?;
+
+        match receiver.recv().unwrap() {
+            Ok(value) => {
+                let value_resp = value
+                    .into_iter()
+                    .map(|x| serde_json::to_value(WebElement::new(x)).unwrap())
+                    .collect::<Vec<Value>>();
+                let value_resp = serde_json::Value::Array(value_resp);
+                Ok(WebDriverResponse::Generic(ValueResponse(value_resp)))
+            },
+            Err(_) => Err(WebDriverError::new(
+                ErrorStatus::InvalidSelector,
+                "Invalid Selector",
+            )),
+        }
+    }
+
     // https://w3c.github.io/webdriver/webdriver-spec.html#get-element-rect
     fn handle_element_rect(&self, element: &WebElement) -> WebDriverResult<WebDriverResponse> {
         let (sender, receiver) = ipc::channel().unwrap();
@@ -1273,6 +1311,9 @@ impl WebDriverHandler<ServoExtensionRoute> for Handler {
             WebDriverCommand::FindElementElement(ref element, ref parameters) => {
                 self.handle_find_element_element(element, parameters)
             },
+            WebDriverCommand::FindElementElements(ref element, ref parameters) => {
+                self.handle_find_elements_from_element(element, parameters)
+            },
             WebDriverCommand::GetNamedCookie(ref name) => self.handle_get_cookie(name),
             WebDriverCommand::GetCookies => self.handle_get_cookies(),
             WebDriverCommand::GetActiveElement => self.handle_active_element(),
@@ -1303,7 +1344,7 @@ impl WebDriverHandler<ServoExtensionRoute> for Handler {
             },
             _ => Err(WebDriverError::new(
                 ErrorStatus::UnsupportedOperation,
-                "Command not implemented",
+                format!("Command not implemented: {:?}", msg.command),
             )),
         }
     }