Auto merge of #249 - canaltinova:form-owner, r=jdm

Implement support for form owner

This is rebased version of #137. Fixed merge conflicts, updated to current codebase and addressed some comments. But there are still some todo's needs to be addressed. Servo side of this changes is currently WIP. Opening this for early feedbacks.

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/html5ever/249)
<!-- Reviewable:end -->

Author: bors-servo

examples/noop-tree-builder.rs

@@ -57,6 +57,10 @@ impl TreeSink for Sink {
         x == y
     }
 
+    fn same_tree(&self, _x: usize, _y: usize) -> bool {
+        true
+    }
+
     fn elem_name(&self, target: usize) -> QualName {
         self.names.get(&target).expect("not an element").clone()
     }
@@ -71,13 +75,15 @@ impl TreeSink for Sink {
         self.get_id()
     }
 
+    fn has_parent_node(&self, _node: usize) -> bool {
+        // `node` will have a parent unless a script moved it, and we're
+        // not running scripts.  Therefore we can aways return true.
+        true
+    }
+
     fn append_before_sibling(&mut self,
             _sibling: usize,
-            _new_node: NodeOrText<usize>) -> Result<(), NodeOrText<usize>> {
-        // `sibling` will have a parent unless a script moved it, and we're
-        // not running scripts.  Therefore we can aways return `Ok(())`.
-        Ok(())
-    }
+            _new_node: NodeOrText<usize>) { }
 
     fn parse_error(&mut self, _msg: Cow<'static, str>) { }
     fn set_quirks_mode(&mut self, _mode: QuirksMode) { }

examples/print-tree-actions.rs

@@ -82,6 +82,12 @@ impl TreeSink for Sink {
         id
     }
 
+    fn has_parent_node(&self, _node: usize) -> bool  {
+        // `node` will have a parent unless a script moved it, and we're
+        // not running scripts.  Therefore we can aways return true
+        true
+    }
+
     fn append(&mut self, parent: usize, child: NodeOrText<usize>) {
         match child {
             AppendNode(n)
@@ -93,17 +99,13 @@ impl TreeSink for Sink {
 
     fn append_before_sibling(&mut self,
             sibling: usize,
-            new_node: NodeOrText<usize>) -> Result<(), NodeOrText<usize>> {
+            new_node: NodeOrText<usize>) {
         match new_node {
             AppendNode(n)
                 => println!("Append node {} before {}", n, sibling),
             AppendText(t)
                 => println!("Append text before {}: \"{}\"", sibling, escape_default(&t)),
         }
-
-        // `sibling` will have a parent unless a script moved it, and we're
-        // not running scripts.  Therefore we can aways return `Ok(())`.
-        Ok(())
     }
 
     fn append_doctype_to_document(&mut self,
@@ -121,6 +123,12 @@ impl TreeSink for Sink {
         }
     }
 
+    fn associate_with_form(&mut self, _target: usize, _form: usize) {
+        // No form owner support. Since same_tree always returns
+        // true we cannot be sure that this associate_with_form call is
+        // valid
+    }
+
     fn remove_from_parent(&mut self, target: usize) {
         println!("Remove {} from parent", target);
     }

src/rcdom.rs

@@ -223,6 +223,11 @@ impl TreeSink for RcDom {
         new_node(Comment(text))
     }
 
+    fn has_parent_node(&self, node: Handle) -> bool {
+        let node = node.borrow();
+        node.parent.is_some()
+    }
+
     fn append(&mut self, parent: Handle, child: NodeOrText<Handle>) {
         // Append to an existing Text node if we have one.
         match child {
@@ -241,8 +246,9 @@ impl TreeSink for RcDom {
 
     fn append_before_sibling(&mut self,
             sibling: Handle,
-            child: NodeOrText<Handle>) -> Result<(), NodeOrText<Handle>> {
-        let (parent, i) = unwrap_or_return!(get_parent_and_index(&sibling), Err(child));
+            child: NodeOrText<Handle>) {
+        let (parent, i) = get_parent_and_index(&sibling)
+            .expect("append_before_sibling called on node without parent");
 
         let child = match (child, i) {
             // No previous node.
@@ -253,7 +259,7 @@ impl TreeSink for RcDom {
                 let parent = parent.borrow();
                 let prev = &parent.children[i-1];
                 if append_to_existing_text(prev, &text) {
-                    return Ok(());
+                    return;
                 }
                 new_node(Text(text))
             }
@@ -271,7 +277,6 @@ impl TreeSink for RcDom {
 
         child.borrow_mut().parent = Some(Rc::downgrade(&parent));
         parent.borrow_mut().children.insert(i, child);
-        Ok(())
     }
 
     fn append_doctype_to_document(&mut self,

src/tree_builder/actions.rs

@@ -210,40 +210,8 @@ impl<Handle, Sink> TreeBuilderActions<Handle>
 
     // Insert at the "appropriate place for inserting a node".
     fn insert_appropriately(&mut self, child: NodeOrText<Handle>, override_target: Option<Handle>) {
-        declare_tag_set!(foster_target = "table" "tbody" "tfoot" "thead" "tr");
-        let target = override_target.unwrap_or_else(|| self.current_node());
-        if !(self.foster_parenting && self.elem_in(target.clone(), foster_target)) {
-            if self.html_elem_named(target.clone(), local_name!("template")) {
-                // No foster parenting (inside template).
-                let contents = self.sink.get_template_contents(target);
-                self.sink.append(contents, child);
-            } else {
-                // No foster parenting (the common case).
-                self.sink.append(target, child);
-            }
-            return;
-        }
-
-        // Foster parenting
-        let mut iter = self.open_elems.iter().rev().peekable();
-        while let Some(elem) = iter.next() {
-            if self.html_elem_named(elem.clone(), local_name!("template")) {
-                let contents = self.sink.get_template_contents(elem.clone());
-                self.sink.append(contents, child);
-                return;
-            } else if self.html_elem_named(elem.clone(), local_name!("table")) {
-                // Try inserting "inside last table's parent node, immediately before last table"
-                if let Err(child) = self.sink.append_before_sibling(elem.clone(), child) {
-                    // If last_table has no parent, we regain ownership of the child.
-                    // Insert "inside previous element, after its last child (if any)"
-                    let previous_element = (*iter.peek().unwrap()).clone();
-                    self.sink.append(previous_element, child);
-                }
-                return;
-            }
-        }
-        let html_elem = self.html_elem();
-        self.sink.append(html_elem, child);
+        let insertion_point = self.appropriate_place_for_insertion(override_target);
+        self.insert_at(insertion_point, child);
     }
 
     fn adoption_agency(&mut self, subject: LocalName) {
@@ -775,10 +743,40 @@ impl<Handle, Sink> TreeBuilderActions<Handle>
         // FIXME: application cache selection algorithm
     }
 
+    // https://html.spec.whatwg.org/multipage/#create-an-element-for-the-token
     fn insert_element(&mut self, push: PushFlag, ns: Namespace, name: LocalName, attrs: Vec<Attribute>)
             -> Handle {
-        let elem = self.sink.create_element(QualName::new(ns, name), attrs);
-        self.insert_appropriately(AppendNode(elem.clone()), None);
+        declare_tag_set!(form_associatable =
+            "button" "fieldset" "input" "object"
+            "output" "select" "textarea" "img");
+
+        declare_tag_set!(listed = [form_associatable] - "img");
+
+        // Step 7.
+        let qname = QualName::new(ns, name);
+        let elem = self.sink.create_element(qname.clone(), attrs.clone());
+
+        let insertion_point = self.appropriate_place_for_insertion(None);
+        let tree_node = match insertion_point {
+            LastChild(ref p) |
+            BeforeSibling(ref p) => p.clone()
+        };
+
+        // Step 12.
+        if form_associatable(qname.clone()) &&
+           self.form_elem.is_some() &&
+           !self.in_html_elem_named(local_name!("template")) &&
+           !(listed(qname.clone()) &&
+                attrs.iter().any(|a| a.name == qualname!("","form"))) {
+
+               let form = self.form_elem.as_ref().unwrap().clone();
+               if self.sink.same_tree(tree_node, form.clone()) {
+                   self.sink.associate_with_form(elem.clone(), form)
+               }
+        }
+
+        self.insert_at(insertion_point, AppendNode(elem.clone()));
+
         match push {
             Push => self.push(&elem),
             NoPush => (),

src/tree_builder/interface.rs

@@ -72,6 +72,11 @@ pub trait TreeSink {
     /// Do two handles refer to the same node?
     fn same_node(&self, x: Self::Handle, y: Self::Handle) -> bool;
 
+    /// Are two handles present in the same tree
+    fn same_tree(&self, x: Self::Handle, y: Self::Handle) -> bool {
+        true
+    }
+
     /// What is the name of this element?
     ///
     /// Should never be called on a non-element node;
@@ -93,15 +98,18 @@ pub trait TreeSink {
     /// Create a comment node.
     fn create_comment(&mut self, text: StrTendril) -> Self::Handle;
 
+    /// Does the node have a parent?
+    fn has_parent_node(&self, node: Self::Handle) -> bool;
+
     /// Append a node as the last child of the given node.  If this would
     /// produce adjacent sibling text nodes, it should concatenate the text
     /// instead.
     ///
     /// The child node will not already have a parent.
     fn append(&mut self, parent: Self::Handle, child: NodeOrText<Self::Handle>);
 
-    /// Append a node as the sibling immediately before the given node.  If that node
-    /// has no parent, do nothing and return Err(new_node).
+    /// Append a node as the sibling immediately before the given node.
+    /// This method will only be called if has_parent_node(sibling) is true
     ///
     /// The tree builder promises that `sibling` is not a text node.  However its
     /// old previous sibling, which would become the new node's previous sibling,
@@ -111,7 +119,7 @@ pub trait TreeSink {
     /// NB: `new_node` may have an old parent, from which it should be removed.
     fn append_before_sibling(&mut self,
         sibling: Self::Handle,
-        new_node: NodeOrText<Self::Handle>) -> Result<(), NodeOrText<Self::Handle>>;
+        new_node: NodeOrText<Self::Handle>);
 
     /// Append a `DOCTYPE` element to the `Document` node.
     fn append_doctype_to_document(&mut self,
@@ -124,6 +132,9 @@ pub trait TreeSink {
     /// with something else than an element.
     fn add_attrs_if_missing(&mut self, target: Self::Handle, attrs: Vec<Attribute>);
 
+    /// Associate the given form-associatable element with the form element
+    fn associate_with_form(&mut self, target: Self::Handle, form: Self::Handle) {}
+
     /// Detach the given node from its parent.
     fn remove_from_parent(&mut self, target: Self::Handle);
 

src/tree_builder/mod.rs

@@ -369,6 +369,53 @@ impl<Handle, Sink> TreeBuilder<Handle, Sink>
     pub fn is_fragment(&self) -> bool {
         self.context_elem.is_some()
     }
+
+    fn appropriate_place_for_insertion(&mut self,
+                                       override_target: Option<Handle>)
+                                       -> InsertionPoint<Handle> {
+        use self::tag_sets::*;
+
+        declare_tag_set!(foster_target = "table" "tbody" "tfoot" "thead" "tr");
+        let target = override_target.unwrap_or_else(|| self.current_node());
+        if !(self.foster_parenting && self.elem_in(target.clone(), foster_target)) {
+            if self.html_elem_named(target.clone(), local_name!("template")) {
+                // No foster parenting (inside template).
+                let contents = self.sink.get_template_contents(target);
+                return LastChild(contents);
+            } else {
+                // No foster parenting (the common case).
+                return LastChild(target);
+            }
+        }
+
+        // Foster parenting
+        let mut iter = self.open_elems.iter().rev().peekable();
+        while let Some(elem) = iter.next() {
+            if self.html_elem_named(elem.clone(), local_name!("template")) {
+                let contents = self.sink.get_template_contents(elem.clone());
+                return LastChild(contents);
+            } else if self.html_elem_named(elem.clone(), local_name!("table")) {
+                // Try inserting "inside last table's parent node, immediately before last table"
+                if self.sink.has_parent_node(elem.clone()) {
+                    return BeforeSibling(elem.clone());
+                } else {
+                    // If elem has no parent, we regain ownership of the child.
+                    // Insert "inside previous element, after its last child (if any)"
+                    let previous_element = (*iter.peek().unwrap()).clone();
+                    return LastChild(previous_element);
+                }
+            }
+        }
+        let html_elem = self.html_elem();
+        LastChild(html_elem)
+    }
+
+    fn insert_at(&mut self, insertion_point: InsertionPoint<Handle>, child: NodeOrText<Handle>) {
+        match insertion_point {
+            LastChild(parent) => self.sink.append(parent, child),
+            BeforeSibling(sibling) => self.sink.append_before_sibling(sibling, child)
+        }
+    }
 }
 
 impl<Handle, Sink> TokenSink
@@ -529,13 +576,18 @@ mod test {
             self.rcdom.create_comment(text)
         }
 
+        fn has_parent_node(&self, node: Handle) -> bool {
+            let node = node.borrow();
+            node.parent.is_some()
+        }
+
         fn append(&mut self, parent: Handle, child: NodeOrText<Handle>) {
             self.rcdom.append(parent, child)
         }
 
         fn append_before_sibling(&mut self,
                 sibling: Handle,
-                child: NodeOrText<Handle>) -> Result<(), NodeOrText<Handle>> {
+                child: NodeOrText<Handle>) {
             self.rcdom.append_before_sibling(sibling, child)
         }
 

src/tree_builder/types.rs

@@ -19,6 +19,7 @@ pub use self::SplitStatus::*;
 pub use self::Token::*;
 pub use self::ProcessResult::*;
 pub use self::FormatEntry::*;
+pub use self::InsertionPoint::*;
 
 #[derive(PartialEq, Eq, Copy, Clone, Debug)]
 pub enum InsertionMode {
@@ -80,3 +81,13 @@ pub enum FormatEntry<Handle> {
     Element(Handle, Tag),
     Marker,
 }
+
+pub enum InsertionPoint<Handle> {
+    /// Holds the parent
+    LastChild(Handle),
+    /// Holds the sibling before which the node will be inserted
+    /// TODO: Is the parent node needed? Is there a problem with using
+    /// the sibling to find if the form element is in the same home
+    /// subtree?
+    BeforeSibling(Handle)
+}