Auto merge of #27100 - muodov:master, r=gterzian

Implement HTMLFormElement.requestSubmit()

<!-- Please describe your changes on the following line: -->
This PR contains an implementation of [HTMLFormElement.requestSubmit()](https://html.spec.whatwg.org/multipage/forms.html#dom-form-requestsubmit)

This is literally my first hundred lines of Rust code, so if I crossed a few sacred lines here and there, please go easy on me :)

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `___` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #23417

<!-- Either: -->
- [x] [WPT tests](https://github.com/servo/servo/blob/master/tests/wpt/web-platform-tests/html/semantics/forms/the-form-element/form-requestsubmit.html) for these changes
There are two tests that still fail because we don't support `:invalid` CSS selector (see #10781). I verified that they pass if you change them to not use `:invalid`. Should be unlocked by #26729.

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components/script/dom/htmlbuttonelement.rs

@@ -77,6 +77,11 @@ impl HTMLButtonElement {
             document,
         )
     }
+
+    #[inline]
+    pub fn is_submit_button(&self) -> bool {
+        self.button_type.get() == ButtonType::Submit
+    }
 }
 
 impl HTMLButtonElementMethods for HTMLButtonElement {

components/script/dom/htmlformelement.rs

@@ -16,6 +16,7 @@ use crate::dom::bindings::codegen::Bindings::HTMLInputElementBinding::HTMLInputE
 use crate::dom::bindings::codegen::Bindings::HTMLTextAreaElementBinding::HTMLTextAreaElementMethods;
 use crate::dom::bindings::codegen::Bindings::NodeListBinding::NodeListMethods;
 use crate::dom::bindings::codegen::Bindings::WindowBinding::WindowBinding::WindowMethods;
+use crate::dom::bindings::error::{Error, Fallible};
 use crate::dom::bindings::inheritance::{Castable, ElementTypeId, HTMLElementTypeId, NodeTypeId};
 use crate::dom::bindings::refcounted::Trusted;
 use crate::dom::bindings::reflector::DomObject;
@@ -88,6 +89,7 @@ pub struct HTMLFormElement {
     generation_id: Cell<GenerationId>,
     controls: DomRefCell<Vec<Dom<Element>>>,
     past_names_map: DomRefCell<HashMap<Atom, (Dom<Element>, Tm)>>,
+    firing_submission_events: Cell<bool>,
 }
 
 impl HTMLFormElement {
@@ -104,6 +106,7 @@ impl HTMLFormElement {
             generation_id: Cell::new(GenerationId(0)),
             controls: DomRefCell::new(Vec::new()),
             past_names_map: DomRefCell::new(HashMap::new()),
+            firing_submission_events: Cell::new(false),
         }
     }
 
@@ -243,6 +246,67 @@ impl HTMLFormElementMethods for HTMLFormElement {
         self.submit(SubmittedFrom::FromForm, FormSubmitter::FormElement(self));
     }
 
+    // https://html.spec.whatwg.org/multipage/#dom-form-requestsubmit
+    fn RequestSubmit(&self, submitter: Option<&HTMLElement>) -> Fallible<()> {
+        let submitter: FormSubmitter = match submitter {
+            Some(submitter_element) => {
+                // Step 1.1
+                let error_not_a_submit_button =
+                    Err(Error::Type("submitter must be a submit button".to_string()));
+
+                let element = match submitter_element.upcast::<Node>().type_id() {
+                    NodeTypeId::Element(ElementTypeId::HTMLElement(element)) => element,
+                    _ => {
+                        return error_not_a_submit_button;
+                    },
+                };
+
+                let submit_button = match element {
+                    HTMLElementTypeId::HTMLInputElement => FormSubmitter::InputElement(
+                        &submitter_element
+                            .downcast::<HTMLInputElement>()
+                            .expect("Failed to downcast submitter elem to HTMLInputElement."),
+                    ),
+                    HTMLElementTypeId::HTMLButtonElement => FormSubmitter::ButtonElement(
+                        &submitter_element
+                            .downcast::<HTMLButtonElement>()
+                            .expect("Failed to downcast submitter elem to HTMLButtonElement."),
+                    ),
+                    _ => {
+                        return error_not_a_submit_button;
+                    },
+                };
+
+                if !submit_button.is_submit_button() {
+                    return error_not_a_submit_button;
+                }
+
+                let submitters_owner = submit_button.form_owner();
+
+                // Step 1.2
+                let owner = match submitters_owner {
+                    Some(owner) => owner,
+                    None => {
+                        return Err(Error::NotFound);
+                    },
+                };
+
+                if *owner != *self {
+                    return Err(Error::NotFound);
+                }
+
+                submit_button
+            },
+            None => {
+                // Step 2
+                FormSubmitter::FormElement(&self)
+            },
+        };
+        // Step 3
+        self.submit(SubmittedFrom::NotFromForm, submitter);
+        Ok(())
+    }
+
     // https://html.spec.whatwg.org/multipage/#dom-form-reset
     fn Reset(&self) {
         self.reset(ResetFrom::FromForm);
@@ -599,28 +663,38 @@ impl HTMLFormElement {
         let base = doc.base_url();
         // TODO: Handle browsing contexts (Step 4, 5)
         // Step 6
-        if submit_method_flag == SubmittedFrom::NotFromForm && !submitter.no_validate(self) {
-            if self.interactive_validation().is_err() {
-                // TODO: Implement event handlers on all form control elements
-                self.upcast::<EventTarget>().fire_event(atom!("invalid"));
+        if submit_method_flag == SubmittedFrom::NotFromForm {
+            // Step 6.1
+            if self.firing_submission_events.get() {
                 return;
             }
-        }
-        // Step 7
-        // spec calls this "submitterButton" but it doesn't have to be a button,
-        // just not be the form itself
-        let submitter_button = match submitter {
-            FormSubmitter::FormElement(f) => {
-                if f == self {
-                    None
-                } else {
-                    Some(f.upcast::<HTMLElement>())
+            // Step 6.2
+            self.firing_submission_events.set(true);
+            // Step 6.3
+            if !submitter.no_validate(self) {
+                if self.interactive_validation().is_err() {
+                    // TODO: Implement event handlers on all form control elements
+                    self.upcast::<EventTarget>().fire_event(atom!("invalid"));
+                    self.firing_submission_events.set(false);
+                    return;
                 }
-            },
-            FormSubmitter::InputElement(i) => Some(i.upcast::<HTMLElement>()),
-            FormSubmitter::ButtonElement(b) => Some(b.upcast::<HTMLElement>()),
-        };
-        if submit_method_flag == SubmittedFrom::NotFromForm {
+            }
+            // Step 6.4
+            // spec calls this "submitterButton" but it doesn't have to be a button,
+            // just not be the form itself
+            let submitter_button = match submitter {
+                FormSubmitter::FormElement(f) => {
+                    if f == self {
+                        None
+                    } else {
+                        Some(f.upcast::<HTMLElement>())
+                    }
+                },
+                FormSubmitter::InputElement(i) => Some(i.upcast::<HTMLElement>()),
+                FormSubmitter::ButtonElement(b) => Some(b.upcast::<HTMLElement>()),
+            };
+
+            // Step 6.5
             let event = SubmitEvent::new(
                 &self.global(),
                 atom!("submit"),
@@ -630,48 +704,51 @@ impl HTMLFormElement {
             );
             let event = event.upcast::<Event>();
             event.fire(self.upcast::<EventTarget>());
+
+            // Step 6.6
+            self.firing_submission_events.set(false);
+            // Step 6.7
             if event.DefaultPrevented() {
                 return;
             }
-
-            // Step 7-3
+            // Step 6.8
             if self.upcast::<Element>().cannot_navigate() {
                 return;
             }
         }
 
-        // Step 8
+        // Step 7
         let encoding = self.pick_encoding();
 
-        // Step 9
+        // Step 8
         let mut form_data = match self.get_form_dataset(Some(submitter), Some(encoding)) {
             Some(form_data) => form_data,
             None => return,
         };
 
-        // Step 10
+        // Step 9
         if self.upcast::<Element>().cannot_navigate() {
             return;
         }
 
-        // Step 11
+        // Step 10
         let mut action = submitter.action();
 
-        // Step 12
+        // Step 11
         if action.is_empty() {
             action = DOMString::from(base.as_str());
         }
-        // Step 13-14
+        // Step 12-13
         let action_components = match base.join(&action) {
             Ok(url) => url,
             Err(_) => return,
         };
-        // Step 15-17
+        // Step 14-16
         let scheme = action_components.scheme().to_owned();
         let enctype = submitter.enctype();
         let method = submitter.method();
 
-        // Step 18-21
+        // Step 17-21
         let target_attribute_value = submitter.target();
         let source = doc.browsing_context().unwrap();
         let (maybe_chosen, _new) = source.choose_browsing_context(target_attribute_value, false);
@@ -1232,11 +1309,14 @@ pub enum FormMethod {
     FormDialog,
 }
 
+/// <https://html.spec.whatwg.org/multipage/#form-associated-element>
 #[derive(Clone, Copy, MallocSizeOf)]
 pub enum FormSubmitter<'a> {
     FormElement(&'a HTMLFormElement),
     InputElement(&'a HTMLInputElement),
-    ButtonElement(&'a HTMLButtonElement), // TODO: image submit, etc etc
+    ButtonElement(&'a HTMLButtonElement),
+    // TODO: implement other types of form associated elements
+    // (including custom elements) that can be passed as submitter.
 }
 
 impl<'a> FormSubmitter<'a> {
@@ -1332,6 +1412,27 @@ impl<'a> FormSubmitter<'a> {
                 ),
         }
     }
+
+    // https://html.spec.whatwg.org/multipage/#concept-submit-button
+    fn is_submit_button(&self) -> bool {
+        match *self {
+            // https://html.spec.whatwg.org/multipage/#image-button-state-(type=image)
+            // https://html.spec.whatwg.org/multipage/#submit-button-state-(type=submit)
+            FormSubmitter::InputElement(input_element) => input_element.is_submit_button(),
+            // https://html.spec.whatwg.org/multipage/#attr-button-type-submit-state
+            FormSubmitter::ButtonElement(button_element) => button_element.is_submit_button(),
+            _ => false,
+        }
+    }
+
+    // https://html.spec.whatwg.org/multipage/#form-owner
+    fn form_owner(&self) -> Option<DomRoot<HTMLFormElement>> {
+        match *self {
+            FormSubmitter::ButtonElement(button_el) => button_el.form_owner(),
+            FormSubmitter::InputElement(input_el) => input_el.form_owner(),
+            _ => None,
+        }
+    }
 }
 
 pub trait FormControl: DomObject {

components/script/dom/htmlinputelement.rs

@@ -405,6 +405,12 @@ impl HTMLInputElement {
         self.input_type.get()
     }
 
+    #[inline]
+    pub fn is_submit_button(&self) -> bool {
+        let input_type = self.input_type.get();
+        input_type == InputType::Submit || input_type == InputType::Image
+    }
+
     pub fn disable_sanitization(&self) {
         self.sanitization_flag.set(false);
     }

components/script/dom/webidls/HTMLFormElement.webidl

@@ -32,6 +32,7 @@ interface HTMLFormElement : HTMLElement {
   getter (RadioNodeList or Element) (DOMString name);
 
   void submit();
+  [Throws] void requestSubmit(optional HTMLElement? submitter = null);
   [CEReactions]
   void reset();
   boolean checkValidity();

tests/wpt/metadata-layout-2020/html/dom/idlharness.https.html.ini

@@ -1650,9 +1650,6 @@
 
 
 [idlharness.https.html?include=HTML.*]
-  [HTMLFormElement interface: calling requestSubmit(optional HTMLElement?) on document.createElement("form") with too few arguments must throw TypeError]
-    expected: FAIL
-
   [HTMLTableSectionElement interface: document.createElement("tfoot") must inherit property "align" with the proper type]
     expected: FAIL
 
@@ -2307,9 +2304,6 @@
   [HTMLObjectElement interface: document.createElement("object") must inherit property "archive" with the proper type]
     expected: FAIL
 
-  [HTMLFormElement interface: operation requestSubmit(optional HTMLElement?)]
-    expected: FAIL
-
   [HTMLTableColElement interface: document.createElement("col") must inherit property "chOff" with the proper type]
     expected: FAIL
 

tests/wpt/metadata/html/dom/idlharness.https.html.ini

@@ -3621,9 +3621,6 @@
   [HTMLAreaElement interface: document.createElement("area") must inherit property "download" with the proper type]
     expected: FAIL
 
-  [HTMLFormElement interface: calling requestSubmit(HTMLElement) on document.createElement("form") with too few arguments must throw TypeError]
-    expected: FAIL
-
   [HTMLProgressElement interface: attribute value]
     expected: FAIL
 
@@ -3711,9 +3708,6 @@
   [HTMLImageElement interface: document.createElement("img") must inherit property "loading" with the proper type]
     expected: FAIL
 
-  [HTMLFormElement interface: calling requestSubmit(optional HTMLElement?) on document.createElement("form") with too few arguments must throw TypeError]
-    expected: FAIL
-
   [HTMLSlotElement interface: calling assignedNodes(optional AssignedNodesOptions) on document.createElement("slot") with too few arguments must throw TypeError]
     expected: FAIL
 
@@ -3732,18 +3726,12 @@
   [HTMLAllCollection interface: document.all must inherit property "item(optional DOMString)" with the proper type]
     expected: FAIL
 
-  [HTMLFormElement interface: operation requestSubmit(optional HTMLElement?)]
-    expected: FAIL
-
   [HTMLAllCollection interface: calling item(optional DOMString) on document.all with too few arguments must throw TypeError]
     expected: FAIL
 
   [HTMLAllCollection interface: operation item(optional DOMString)]
     expected: FAIL
 
-  [HTMLFormElement interface: document.createElement("form") must inherit property "requestSubmit(optional HTMLElement?)" with the proper type]
-    expected: FAIL
-
   [HTMLCanvasElement interface: document.createElement("canvas") must inherit property "toBlob(BlobCallback, optional DOMString, optional any)" with the proper type]
     expected: FAIL
 

tests/wpt/metadata/html/semantics/forms/form-submission-0/form-submission-algorithm.html.ini

@@ -1,19 +1,3 @@
 [form-submission-algorithm.html]
-  [If form's firing submission events is true, then return; 'invalid' event]
-    expected: FAIL
-
-  [firing an event named submit; form.requestSubmit(submitter)]
-    expected: FAIL
-
-  [firing an event named submit; form.requestSubmit(null)]
-    expected: FAIL
-
-  [firing an event named submit; form.requestSubmit()]
-    expected: FAIL
-
   [Submission URL should always have a non-null query part]
     expected: FAIL
-
-  [If firing submission events flag of form is true, then return]
-    expected: FAIL
-

tests/wpt/metadata/html/semantics/forms/the-form-element/form-requestsubmit.html.ini

@@ -1,22 +1,6 @@
 [form-requestsubmit.html]
-  [requestSubmit() doesn't run interactive validation reentrantly]
-    expected: FAIL
-
   [The value of the submitter should be appended, and form* attributes of the submitter should be handled.]
     expected: FAIL
 
-  [Passing a submit button not owned by the context object should throw]
-    expected: FAIL
-
-  [requestSubmit() for a disconnected form should not submit the form]
-    expected: FAIL
-
   [requestSubmit() should trigger interactive form validation]
     expected: FAIL
-
-  [requestSubmit() doesn't run form submission reentrantly]
-    expected: FAIL
-
-  [requestSubmit() should accept button[type=submit\], input[type=submit\], and input[type=image\]]
-    expected: FAIL
-