Don't require passing a root element to Document::new (needed for issue #888).

src/components/script/dom/document.rs

@@ -76,6 +76,12 @@ impl AbstractDocument {
             _ => fail!("attempt to downcast a non-HTMLDocument to HTMLDocument")
         }
     }
+
+    pub fn set_root(&mut self, root: AbstractNode<ScriptView>) {
+        self.with_mut_base(|document| {
+            document.set_root(root);
+        });
+    }
 }
 
 pub enum DocumentType {
@@ -85,7 +91,7 @@ pub enum DocumentType {
 }
 
 pub struct Document {
-    root: AbstractNode<ScriptView>,
+    root: Option<AbstractNode<ScriptView>>,
     wrapper: WrapperCache,
     window: Option<@mut Window>,
     doctype: DocumentType,
@@ -94,9 +100,9 @@ pub struct Document {
 
 impl Document {
     #[fixed_stack_segment]
-    pub fn new(root: AbstractNode<ScriptView>, window: Option<@mut Window>, doctype: DocumentType) -> Document {
+    pub fn new(window: Option<@mut Window>, doctype: DocumentType) -> Document {
         Document {
-            root: root,
+            root: None,
             wrapper: WrapperCache::new(),
             window: window,
             doctype: doctype,
@@ -104,14 +110,22 @@ impl Document {
         }
     }
 
+    pub fn set_root(&mut self, root: AbstractNode<ScriptView>) {
+        self.root = Some(root);
+    }
+
     pub fn Constructor(owner: @mut Window) -> Fallible<AbstractDocument> {
+        let cx = owner.page.js_info.get_ref().js_compartment.cx.ptr;
+
+        let mut document = AbstractDocument::as_abstract(cx, @mut Document::new(None, XML));
+
         let root = @HTMLHtmlElement {
             htmlelement: HTMLElement::new(HTMLHtmlElementTypeId, ~"html")
         };
-
-        let cx = owner.page.js_info.get_ref().js_compartment.cx.ptr;
         let root = unsafe { Node::as_abstract_node(cx, root) };
-        Ok(AbstractDocument::as_abstract(cx, @mut Document::new(root, None, XML)))
+        document.set_root(root);
+
+        Ok(document)
     }
 }
 
@@ -208,7 +222,7 @@ impl Document {
     }
 
     pub fn GetDocumentElement(&self) -> Option<AbstractNode<ScriptView>> {
-        Some(self.root)
+        self.root
     }
 
     fn get_cx(&self) -> *JSContext {
@@ -288,7 +302,10 @@ impl Document {
                 fail!("no SVG document yet")
             },
             _ => {
-                let _ = for node in self.root.traverse_preorder() {
+                match self.root {
+                    None => {},
+                    Some(root) => {
+                        let _ = for node in root.traverse_preorder() {
                             if node.type_id() != ElementNodeTypeId(HTMLTitleElementTypeId) {
                                 loop;
                             }
@@ -304,6 +321,8 @@ impl Document {
                         };
                     }
                 }
+            }
+        }
         let v: ~[&str] = title.word_iter().collect();
         title = v.connect(" ");
         title = title.trim().to_owned();
@@ -317,7 +336,10 @@ impl Document {
             },
             _ => {
                 let (_scope, cx) = self.get_scope_and_cx();
-                let _ = for node in self.root.traverse_preorder() {
+                match self.root {
+                    None => {},
+                    Some(root) => {
+                        let _ = for node in root.traverse_preorder() {
                             if node.type_id() != ElementNodeTypeId(HTMLHeadElementTypeId) {
                                 loop;
                             }
@@ -347,6 +369,8 @@ impl Document {
                         };
                     }
                 }
+            }
+        }
         Ok(())
     }
 
@@ -440,7 +464,10 @@ impl Document {
 
     pub fn createHTMLCollection(&self, callback: &fn(elem: &Element) -> bool) -> @mut HTMLCollection {
         let mut elements = ~[];
-        let _ = for child in self.root.traverse_preorder() {
+        match self.root {
+            None => {},
+            Some(root) => {
+                let _ = for child in root.traverse_preorder() {
                     if child.is_element() {
                         do child.with_imm_element |elem| {
                             if callback(elem) {
@@ -449,6 +476,8 @@ impl Document {
                         }
                     }
                 };
+            }
+        }
         let (scope, cx) = self.get_scope_and_cx();
         HTMLCollection::new(elements, cx, scope)
     }
@@ -469,13 +498,16 @@ impl Document {
 impl Traceable for Document {
     #[fixed_stack_segment]
     fn trace(&self, tracer: *mut JSTracer) {
+        match self.root {
+            None => {},
+            Some(root) => {
                 unsafe {
                     (*tracer).debugPrinter = ptr::null();
                     (*tracer).debugPrintIndex = -1;
                     do "root".to_c_str().with_ref |name| {
                         (*tracer).debugPrintArg = name as *libc::c_void;
                         debug!("tracing root node");
-                do self.root.with_base |node| {
+                        do root.with_base |node| {
                             JS_CallTracer(tracer as *JSTracer,
                                           node.wrapper.wrapper,
                                           JSTRACE_OBJECT as u32);
@@ -483,4 +515,6 @@ impl Traceable for Document {
                     }
                 }
             }
+        }
+    }
 }

src/components/script/dom/domparser.rs

@@ -41,26 +41,26 @@ impl DOMParser {
                            _s: &DOMString,
                            ty: DOMParserBinding::SupportedType)
                            -> Fallible<AbstractDocument> {
-        unsafe {
-            let root = @HTMLHtmlElement {
-                htmlelement: HTMLElement::new(HTMLHtmlElementTypeId, ~"html")
-            };
-
-            let root = Node::as_abstract_node((*self.owner.page).js_info.get_ref().js_compartment.cx.ptr, root);
         let cx = (*self.owner.page).js_info.get_ref().js_compartment.cx.ptr;
-
+        let mut document = match ty {
-            match ty {
             Text_html => {
-                    Ok(HTMLDocument::new(root, None))
+                HTMLDocument::new(None)
             }
             Text_xml => {
-                    Ok(AbstractDocument::as_abstract(cx, @mut Document::new(root, None, XML)))
+                AbstractDocument::as_abstract(cx, @mut Document::new(None, XML))
             }
             _ => {
                 fail!("unsupported document type")
             }
-            }
+        };
-        }
+
+        let root = @HTMLHtmlElement {
+            htmlelement: HTMLElement::new(HTMLHtmlElementTypeId, ~"html")
+        };
+        let root = unsafe { Node::as_abstract_node(cx, root) };
+        document.set_root(root);
+
+        Ok(document)
     }
 }
 

src/components/script/dom/htmldocument.rs

@@ -24,9 +24,9 @@ pub struct HTMLDocument {
 }
 
 impl HTMLDocument {
-    pub fn new(root: AbstractNode<ScriptView>, window: Option<@mut Window>) -> AbstractDocument {
+    pub fn new(window: Option<@mut Window>) -> AbstractDocument {
         let doc = @mut HTMLDocument {
-            parent: Document::new(root, window, HTML)
+            parent: Document::new(window, HTML)
         };
 
         let compartment = window.get_ref().page.js_info.get_ref().js_compartment;
@@ -70,8 +70,11 @@ impl HTMLDocument {
     }
 
     pub fn GetHead(&self) -> Option<AbstractNode<ScriptView>> {
+        match self.parent.root {
+            None => None,
+            Some(root) => {
                 let mut headNode: Option<AbstractNode<ScriptView>> = None;
-        let _ = for child in self.parent.root.traverse_preorder() {
+                let _ = for child in root.traverse_preorder() {
                     if child.type_id() == ElementNodeTypeId(HTMLHeadElementTypeId) {
                         headNode = Some(child);
                         break;
@@ -79,6 +82,8 @@ impl HTMLDocument {
                 };
                 headNode 
             }
+        }
+    }
 
     pub fn Images(&self) -> @mut HTMLCollection {
         self.parent.createHTMLCollection(|elem| eq_slice(elem.tag_name, "img"))

src/components/script/script_task.rs

@@ -217,21 +217,27 @@ impl<'self> Iterator<@mut Page> for PageTreeIterator<'self> {
 impl Page {
     /// Adds the given damage.
     fn damage(&mut self, level: DocumentDamageLevel) {
+        let root = do self.frame.get_ref().document.with_base |doc| { doc.root };
+        match root {
+            None => {},
+            Some(root) => {
                 match self.damage {
                     None => {}
                     Some(ref mut damage) => {
                         // FIXME(pcwalton): This is wrong. We should trace up to the nearest ancestor.
-                damage.root = do self.frame.get_ref().document.with_base |doc| { doc.root };
+                        damage.root = root;
                         damage.level.add(level);
                         return
                     }
                 }
 
                 self.damage = Some(DocumentDamage {
-            root: do self.frame.get_ref().document.with_base |doc| { doc.root },
+                    root: root,
                     level: level,
                 })
             }
+        };
+    }
 
     /// Sends a ping to layout and waits for the response. The response will arrive when the
     /// layout task has finished any pending request messages.
@@ -269,7 +275,17 @@ impl Page {
     ///
     /// This function fails if there is no root frame.
     fn reflow(&mut self, goal: ReflowGoal, script_chan: ScriptChan, compositor: @ScriptListener) {
-
+        let root = match self.frame {
+            None => fail!(~"Tried to relayout with no root frame!"),
+            Some(ref frame) => {
+                do frame.document.with_base |doc| {
+                    doc.root
+                }
+            }
+        };
+        match root {
+            None => {},
+            Some(root) => {
                 debug!("script: performing reflow for goal %?", goal);
 
                 // Now, join the layout so that they will see the latest changes we have made.
@@ -284,12 +300,9 @@ impl Page {
 
                 self.last_reflow_id += 1;
 
-        match self.frame {
-            None => fail!(~"Tried to relayout with no root frame!"),
-            Some(ref frame) => {
                 // Send new document and relevant styles to layout.
                 let reflow = ~Reflow {
-                    document_root: do frame.document.with_base |doc| { doc.root },
+                    document_root: root,
                     url: self.url.get_ref().first().clone(),
                     goal: goal,
                     window_size: self.window_size.get(),
@@ -299,12 +312,12 @@ impl Page {
                     id: self.last_reflow_id,
                 };
 
-                self.layout_chan.send(ReflowMsg(reflow))
+                self.layout_chan.send(ReflowMsg(reflow));
-            }
-        }
 
                 debug!("script: layout forked")
             }
+        }
+    }
 
     /// Reflows the entire document.
     ///
@@ -709,9 +722,10 @@ impl ScriptTask {
                                                                  page.next_subpage_id.clone(),
                                                                  self.constellation_chan.clone());
 
-        let HtmlParserResult {root, discovery_port, url: final_url} = html_parsing_result;
+        let mut document = HTMLDocument::new(Some(window));
 
-        let document = HTMLDocument::new(root, Some(window));
+        let HtmlParserResult {root, discovery_port, url: final_url} = html_parsing_result;
+        document.set_root(root);
 
         // Create the root frame.
         page.frame = Some(Frame {
@@ -817,8 +831,11 @@ impl ScriptTask {
                 let root = do page.frame.expect("root frame is None").document.with_base |doc| {
                     doc.root
                 };
+                if root.is_none() {
+                    return;
+                }
                 let (port, chan) = comm::stream();
-                match page.query_layout(HitTestQuery(root, point, chan), port) {
+                match page.query_layout(HitTestQuery(root.unwrap(), point, chan), port) {
                     Ok(node) => match node {
                         HitTestResponse(node) => {
                             debug!("clicked on %s", node.debug_str());