Auto merge of #25447 - teapotd:form-validation, r=jdm

Form constraint validation

It's almost done, there are few things remaining:

- ~Range underflow, range overflow and step mismatch implementation require #25405~
- ~There are some test failures due to missing DOM parts (#25003)~
- ~`pattern` attribute uses JS regexp syntax. Currently I used regex crate, but it's probably incompatible. Should we use SpiderMonkey's regexp via jsapi?~
- Currently validation errors are reported using `println!`. Are there any better options?
- ~["While the user interface is representing input that the user agent cannot convert to punycode, the control is suffering from bad input."](https://html.spec.whatwg.org/multipage/#e-mail-state-(type%3Demail)%3Asuffering-from-bad-input)~

r? @jdm

---
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #11444
- [x] There are tests for these changes

1 files changed, 49 insertions, 6 deletions

diff --git a/components/script/dom/htmlfieldsetelement.rs b/components/script/dom/htmlfieldsetelement.rs
index a277cf8e2ec..b2b05cbc5c4 100644
--- a/components/script/dom/htmlfieldsetelement.rs
+++ b/components/script/dom/htmlfieldsetelement.rs
@@ -14,6 +14,7 @@ use crate::dom::htmlelement::HTMLElement;
 use crate::dom::htmlformelement::{FormControl, HTMLFormElement};
 use crate::dom::htmllegendelement::HTMLLegendElement;
 use crate::dom::node::{window_from_node, Node, ShadowIncluding};
+use crate::dom::validation::Validatable;
 use crate::dom::validitystate::ValidityState;
 use crate::dom::virtualmethods::VirtualMethods;
 use dom_struct::dom_struct;
@@ -25,6 +26,7 @@ use style::element_state::ElementState;
 pub struct HTMLFieldSetElement {
     htmlelement: HTMLElement,
     form_owner: MutNullableDom<HTMLFormElement>,
+    validity_state: MutNullableDom<ValidityState>,
 }
 
 impl HTMLFieldSetElement {
@@ -41,6 +43,7 @@ impl HTMLFieldSetElement {
                 document,
             ),
             form_owner: Default::default(),
+            validity_state: Default::default(),
         }
     }
 
@@ -75,12 +78,6 @@ impl HTMLFieldSetElementMethods for HTMLFieldSetElement {
         HTMLCollection::create(&window, self.upcast(), filter)
     }
 
-    // https://html.spec.whatwg.org/multipage/#dom-cva-validity
-    fn Validity(&self) -> DomRoot<ValidityState> {
-        let window = window_from_node(self);
-        ValidityState::new(&window, self.upcast())
-    }
-
     // https://html.spec.whatwg.org/multipage/#dom-fieldset-disabled
     make_bool_getter!(Disabled, "disabled");
 
@@ -97,6 +94,36 @@ impl HTMLFieldSetElementMethods for HTMLFieldSetElement {
     fn GetForm(&self) -> Option<DomRoot<HTMLFormElement>> {
         self.form_owner()
     }
+
+    // https://html.spec.whatwg.org/multipage/#dom-cva-willvalidate
+    fn WillValidate(&self) -> bool {
+        self.is_instance_validatable()
+    }
+
+    // https://html.spec.whatwg.org/multipage/#dom-cva-validity
+    fn Validity(&self) -> DomRoot<ValidityState> {
+        self.validity_state()
+    }
+
+    // https://html.spec.whatwg.org/multipage/#dom-cva-checkvalidity
+    fn CheckValidity(&self) -> bool {
+        self.check_validity()
+    }
+
+    // https://html.spec.whatwg.org/multipage/#dom-cva-reportvalidity
+    fn ReportValidity(&self) -> bool {
+        self.report_validity()
+    }
+
+    // https://html.spec.whatwg.org/multipage/#dom-cva-validationmessage
+    fn ValidationMessage(&self) -> DOMString {
+        self.validation_message()
+    }
+
+    // https://html.spec.whatwg.org/multipage/#dom-cva-setcustomvalidity
+    fn SetCustomValidity(&self, error: DOMString) {
+        self.validity_state().set_custom_error_message(error);
+    }
 }
 
 impl VirtualMethods for HTMLFieldSetElement {
@@ -185,3 +212,19 @@ impl FormControl for HTMLFieldSetElement {
         self.upcast::<Element>()
     }
 }
+
+impl Validatable for HTMLFieldSetElement {
+    fn as_element(&self) -> &Element {
+        self.upcast()
+    }
+
+    fn validity_state(&self) -> DomRoot<ValidityState> {
+        self.validity_state
+            .or_init(|| ValidityState::new(&window_from_node(self), self.upcast()))
+    }
+
+    fn is_instance_validatable(&self) -> bool {
+        // fieldset is not a submittable element (https://html.spec.whatwg.org/multipage/#category-submit)
+        false
+    }
+}