Auto merge of #13969 - bbansalWolfPack:master, r=jdm

html form validation initial steps with  test html file

<!-- Please describe your changes on the following line: -->

Added code for initial steps in html form validation.
1. Added methods for trait validatable
2. implemented stub methods for  elements like HTMLInputElement, HTMLButtonElement, etc

<!-- 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
- [ ] These changes fix #__ (github issue number if applicable).

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

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

<!-- Reviewable:start -->

---

This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/13969)

<!-- Reviewable:end -->

components/script/dom/htmlbuttonelement.rs

@@ -21,7 +21,7 @@ use dom::htmlformelement::HTMLFormElement;
 use dom::node::{Node, UnbindContext, document_from_node, window_from_node};
 use dom::nodelist::NodeList;
 use dom::validation::Validatable;
-use dom::validitystate::ValidityState;
+use dom::validitystate::{ValidityState, ValidationFlags};
 use dom::virtualmethods::VirtualMethods;
 use html5ever_atoms::LocalName;
 use std::cell::Cell;
@@ -238,7 +238,16 @@ impl VirtualMethods for HTMLButtonElement {
 
 impl FormControl for HTMLButtonElement {}
 
-impl Validatable for HTMLButtonElement {}
+impl Validatable for HTMLButtonElement {
+    fn is_instance_validatable(&self) -> bool {
+        true
+    }
+    fn validate(&self, validate_flags: ValidationFlags) -> bool {
+        if validate_flags.is_empty() {}
+        // Need more flag check for different validation types later
+        true
+    }
+}
 
 impl Activatable for HTMLButtonElement {
     fn as_element(&self) -> &Element {

components/script/dom/htmlformelement.rs

@@ -35,6 +35,7 @@ use dom::htmloutputelement::HTMLOutputElement;
 use dom::htmlselectelement::HTMLSelectElement;
 use dom::htmltextareaelement::HTMLTextAreaElement;
 use dom::node::{Node, document_from_node, window_from_node};
+use dom::validitystate::ValidationFlags;
 use dom::virtualmethods::VirtualMethods;
 use encoding::EncodingRef;
 use encoding::all::UTF_8;
@@ -470,12 +471,22 @@ impl HTMLFormElement {
         //               form, refactor this when html5ever's form owner PR lands
         // Step 1-3
         let invalid_controls = node.traverse_preorder().filter_map(|field| {
-            if let Some(_el) = field.downcast::<Element>() {
+            if let Some(el) = field.downcast::<Element>() {
-                None // Remove this line if you decide to refactor
+                if el.disabled_state() {
-
+                    None
-                // XXXKiChjang: Form control elements should each have a candidate_for_validation
+                } else {
-                //              and satisfies_constraints methods
+                    let validatable = match el.as_maybe_validatable() {
-
+                        Some(v) => v,
+                        None => return None
+                    };
+                    if !validatable.is_instance_validatable() {
+                        None
+                    } else if validatable.validate(ValidationFlags::empty()) {
+                        None
+                    } else {
+                        Some(FormSubmittableElement::from_element(&el))
+                    }
+                }
             } else {
                 None
             }
@@ -697,7 +708,7 @@ pub enum FormSubmittableElement {
     // KeygenElement(&'a HTMLKeygenElement),
     ObjectElement(Root<HTMLObjectElement>),
     SelectElement(Root<HTMLSelectElement>),
-    TextAreaElement(Root<HTMLTextAreaElement>)
+    TextAreaElement(Root<HTMLTextAreaElement>),
 }
 
 impl FormSubmittableElement {
@@ -710,6 +721,26 @@ impl FormSubmittableElement {
             FormSubmittableElement::TextAreaElement(ref textarea) => textarea.upcast()
         }
     }
+
+    fn from_element(element: &Element) -> FormSubmittableElement {
+        if let Some(input) = element.downcast::<HTMLInputElement>() {
+            FormSubmittableElement::InputElement(Root::from_ref(&input))
+        }
+        else if let Some(input) = element.downcast::<HTMLButtonElement>() {
+            FormSubmittableElement::ButtonElement(Root::from_ref(&input))
+        }
+        else if let Some(input) = element.downcast::<HTMLObjectElement>() {
+            FormSubmittableElement::ObjectElement(Root::from_ref(&input))
+        }
+        else if let Some(input) = element.downcast::<HTMLSelectElement>() {
+            FormSubmittableElement::SelectElement(Root::from_ref(&input))
+        }
+        else if let Some(input) = element.downcast::<HTMLTextAreaElement>() {
+            FormSubmittableElement::TextAreaElement(Root::from_ref(&input))
+        } else {
+            unreachable!()
+        }
+    }
 }
 
 #[derive(Copy, Clone, HeapSizeOf)]

components/script/dom/htmlinputelement.rs

@@ -31,6 +31,7 @@ use dom::node::{Node, NodeDamage, UnbindContext};
 use dom::node::{document_from_node, window_from_node};
 use dom::nodelist::NodeList;
 use dom::validation::Validatable;
+use dom::validitystate::ValidationFlags;
 use dom::virtualmethods::VirtualMethods;
 use html5ever_atoms::LocalName;
 use ipc_channel::ipc::{self, IpcSender};
@@ -1131,7 +1132,16 @@ impl VirtualMethods for HTMLInputElement {
 
 impl FormControl for HTMLInputElement {}
 
-impl Validatable for HTMLInputElement {}
+impl Validatable for HTMLInputElement {
+    fn is_instance_validatable(&self) -> bool {
+        // https://html.spec.whatwg.org/multipage/#candidate-for-constraint-validation
+        true
+    }
+    fn validate(&self, _validate_flags: ValidationFlags) -> bool {
+        // call stub methods defined in validityState.rs file here according to the flags set in validate_flags
+        true
+    }
+}
 
 impl Activatable for HTMLInputElement {
     fn as_element(&self) -> &Element {

components/script/dom/htmlobjectelement.rs

@@ -15,7 +15,7 @@ use dom::htmlelement::HTMLElement;
 use dom::htmlformelement::{FormControl, HTMLFormElement};
 use dom::node::{Node, window_from_node};
 use dom::validation::Validatable;
-use dom::validitystate::ValidityState;
+use dom::validitystate::{ValidityState, ValidationFlags};
 use dom::virtualmethods::VirtualMethods;
 use html5ever_atoms::LocalName;
 use net_traits::image::base::Image;
@@ -89,7 +89,16 @@ impl HTMLObjectElementMethods for HTMLObjectElement {
     }
 }
 
-impl Validatable for HTMLObjectElement {}
+impl Validatable for HTMLObjectElement {
+    fn is_instance_validatable(&self) -> bool {
+        true
+    }
+    fn validate(&self, validate_flags: ValidationFlags) -> bool {
+        if validate_flags.is_empty() {}
+        // Need more flag check for different validation types later
+        true
+    }
+}
 
 impl VirtualMethods for HTMLObjectElement {
     fn super_type(&self) -> Option<&VirtualMethods> {

components/script/dom/htmlselectelement.rs

@@ -28,7 +28,7 @@ use dom::htmloptionscollection::HTMLOptionsCollection;
 use dom::node::{Node, UnbindContext, window_from_node};
 use dom::nodelist::NodeList;
 use dom::validation::Validatable;
-use dom::validitystate::ValidityState;
+use dom::validitystate::{ValidityState, ValidationFlags};
 use dom::virtualmethods::VirtualMethods;
 use html5ever_atoms::LocalName;
 use style::attr::AttrValue;
@@ -384,4 +384,13 @@ impl VirtualMethods for HTMLSelectElement {
 
 impl FormControl for HTMLSelectElement {}
 
-impl Validatable for HTMLSelectElement {}
+impl Validatable for HTMLSelectElement {
+    fn is_instance_validatable(&self) -> bool {
+        true
+    }
+    fn validate(&self, validate_flags: ValidationFlags) -> bool {
+        if validate_flags.is_empty() {}
+        // Need more flag check for different validation types later
+        true
+    }
+}

components/script/dom/htmltextareaelement.rs

@@ -406,4 +406,5 @@ impl VirtualMethods for HTMLTextAreaElement {
 
 impl FormControl for HTMLTextAreaElement {}
 
+
 impl Validatable for HTMLTextAreaElement {}

components/script/dom/validation.rs

@@ -1,5 +1,9 @@
 /* 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 http://mozilla.org/MPL/2.0/. */
+use dom::validitystate::ValidationFlags;
 
-pub trait Validatable {}
+pub trait Validatable {
+    fn is_instance_validatable(&self) -> bool { true }
+    fn validate(&self, _validate_flags: ValidationFlags) -> bool { true }
+}

components/script/dom/validitystate.rs

@@ -26,6 +26,21 @@ pub enum ValidityStatus {
     Valid
 }
 
+bitflags!{
+    pub flags ValidationFlags: u32 {
+        const VALUE_MISSING    = 0b0000000001,
+        const TYPE_MISMATCH    = 0b0000000010,
+        const PATTERN_MISMATCH = 0b0000000100,
+        const TOO_LONG         = 0b0000001000,
+        const TOO_SHORT        = 0b0000010000,
+        const RANGE_UNDERFLOW  = 0b0000100000,
+        const RANGE_OVERFLOW   = 0b0001000000,
+        const STEP_MISMATCH    = 0b0010000000,
+        const BAD_INPUT        = 0b0100000000,
+        const CUSTOM_ERROR     = 0b1000000000,
+    }
+}
+
 // https://html.spec.whatwg.org/multipage/#validitystate
 #[dom_struct]
 pub struct ValidityState {

tests/html/html_validation_test.html

@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<html>
+<body>
+
+<form>
+  First name:<br>
+  <input type="text" name="firstname" value="Mickey" required>
+  <br>
+  Last name:<br>
+  <input type="text" name="lastname" value="Mouse" required>
+  <br><br>
+  <input type="submit" value="Submit">
+</form>
+
+<p>If you click the "Submit" button, the form-data will be sent to a page called "action_page.php".</p>
+
+</body>
+</html>
+
+
+