Bug 562932 - "Implement control attribute for label element" [r=sicking sr=smaug]

content/base/public/nsIDocument.h

@@ -1358,6 +1358,15 @@ public:
   virtual void ResetScrolledToRefAlready() = 0;
   virtual void SetChangeScrollPosWhenScrollingToRef(PRBool aValue) = 0;
 
+  /**
+   * This method is similar to GetElementById() from nsIDOMDocument but it
+   * returns a mozilla::dom::Element instead of a nsIDOMElement.
+   * It prevents converting nsIDOMElement to mozill:dom::Element which is
+   * already converted from mozilla::dom::Element.
+   */
+  virtual mozilla::dom::Element* GetElementById(const nsAString& aElementId,
+                                                nsresult* aResult) = 0;
+
 protected:
   ~nsIDocument()
   {

content/html/content/public/nsIFormControl.h

@@ -174,6 +174,12 @@ public:
    * @return Whether this is a single line text control.
    */
   virtual PRBool IsSingleLineTextControl(PRBool aExcludePassword) const = 0;
+
+  /**
+   * Returns true if this is a labelable form control.
+   * @return Whether this is a labelable form control.
+   */
+  virtual PRBool IsLabelableControl() const = 0;
 };
 
 NS_DEFINE_STATIC_IID_ACCESSOR(nsIFormControl, NS_IFORMCONTROL_IID)

content/html/content/src/nsGenericHTMLElement.cpp

@@ -2686,6 +2686,20 @@ nsGenericHTMLFormElement::IsSingleLineTextControl(PRBool aExcludePassword) const
          (!aExcludePassword && type == NS_FORM_INPUT_PASSWORD);
 }
 
+PRBool
+nsGenericHTMLFormElement::IsLabelableControl() const
+{
+  // Check for non-labelable form controls as they are not numerous.
+  // TODO: datalist should be added to this list.
+  PRInt32 type = GetType();
+  return type != NS_FORM_FIELDSET &&
+         type != NS_FORM_LABEL &&
+         type != NS_FORM_OPTION &&
+         type != NS_FORM_OPTGROUP &&
+         type != NS_FORM_OBJECT &&
+         type != NS_FORM_LEGEND;
+}
+
 PRInt32
 nsGenericHTMLFormElement::IntrinsicState() const
 {

content/html/content/src/nsGenericHTMLElement.h

@@ -793,6 +793,8 @@ public:
 
           PRBool IsSingleLineTextControl(PRBool aExcludePassword) const;
 
+          PRBool IsLabelableControl() const;
+
   // nsIContent
   virtual nsresult BindToTree(nsIDocument* aDocument, nsIContent* aParent,
                               nsIContent* aBindingParent,

content/html/content/src/nsHTMLLabelElement.cpp

@@ -36,6 +36,7 @@
  * ***** END LICENSE BLOCK ***** */
 #include "nsCOMPtr.h"
 #include "nsIDOMHTMLLabelElement.h"
+#include "nsIDOMNSHTMLLabelElement.h"
 #include "nsIDOMHTMLFormElement.h"
 #include "nsIDOMEventTarget.h"
 #include "nsGenericHTMLElement.h"
@@ -53,7 +54,8 @@
 #include "nsFocusManager.h"
 
 class nsHTMLLabelElement : public nsGenericHTMLFormElement,
-                           public nsIDOMHTMLLabelElement
+                           public nsIDOMHTMLLabelElement,
+                           public nsIDOMNSHTMLLabelElement
 {
 public:
   nsHTMLLabelElement(nsINodeInfo *aNodeInfo);
@@ -74,6 +76,9 @@ public:
   // nsIDOMHTMLLabelElement
   NS_DECL_NSIDOMHTMLLABELELEMENT
 
+  // nsIDOMNSHTMLLabelElement
+  NS_DECL_NSIDOMNSHTMLLABELELEMENT
+
   // nsIFormControl
   NS_IMETHOD_(PRInt32) GetType() const { return NS_FORM_LABEL; }
   NS_IMETHOD Reset();
@@ -106,7 +111,7 @@ public:
   virtual nsresult Clone(nsINodeInfo *aNodeInfo, nsINode **aResult) const;
 
 protected:
-  already_AddRefed<nsIContent> GetForContent();
+  already_AddRefed<nsIContent> GetControlContent();
   already_AddRefed<nsIContent> GetFirstFormControl(nsIContent *current);
 
   // XXX It would be nice if we could use an event flag instead.
@@ -140,7 +145,9 @@ DOMCI_DATA(HTMLLabelElement, nsHTMLLabelElement)
 
 // QueryInterface implementation for nsHTMLLabelElement
 NS_INTERFACE_TABLE_HEAD(nsHTMLLabelElement)
-  NS_HTML_CONTENT_INTERFACE_TABLE1(nsHTMLLabelElement, nsIDOMHTMLLabelElement)
+  NS_HTML_CONTENT_INTERFACE_TABLE2(nsHTMLLabelElement,
+                                   nsIDOMHTMLLabelElement,
+                                   nsIDOMNSHTMLLabelElement)
   NS_HTML_CONTENT_INTERFACE_TABLE_TO_MAP_SEGUE(nsHTMLLabelElement,
                                                nsGenericHTMLFormElement)
 NS_HTML_CONTENT_INTERFACE_TABLE_TAIL_CLASSINFO(HTMLLabelElement)
@@ -158,6 +165,18 @@ nsHTMLLabelElement::GetForm(nsIDOMHTMLFormElement** aForm)
   return nsGenericHTMLFormElement::GetForm(aForm);
 }
 
+NS_IMETHODIMP
+nsHTMLLabelElement::GetControl(nsIDOMHTMLElement** aElement)
+{
+  *aElement = nsnull;
+
+  nsCOMPtr<nsIContent> content = GetControlContent();
+  nsCOMPtr<nsIDOMHTMLElement> element = do_QueryInterface(content);
+
+  element.swap(*aElement);
+  return NS_OK;
+}
+
 
 NS_IMPL_STRING_ATTR(nsHTMLLabelElement, AccessKey, accesskey)
 NS_IMPL_STRING_ATTR(nsHTMLLabelElement, HtmlFor, _for)
@@ -168,7 +187,8 @@ nsHTMLLabelElement::Focus()
   // retarget the focus method at the for content
   nsIFocusManager* fm = nsFocusManager::GetFocusManager();
   if (fm) {
-    nsCOMPtr<nsIContent> content = GetForContent();
+    nsCOMPtr<nsIContent> content = GetControlContent();
+
     nsCOMPtr<nsIDOMElement> elem = do_QueryInterface(content);
     if (elem)
       fm->SetFocus(elem, 0);
@@ -244,7 +264,8 @@ nsHTMLLabelElement::PostHandleEvent(nsEventChainPostVisitor& aVisitor)
     return NS_OK;
   }
 
-  nsCOMPtr<nsIContent> content = GetForContent();
+  nsCOMPtr<nsIContent> content = GetControlContent();
+
   if (content && !EventTargetIn(aVisitor.mEvent, content, this)) {
     mHandlingEvent = PR_TRUE;
     switch (aVisitor.mEvent->message) {
@@ -373,7 +394,7 @@ nsHTMLLabelElement::PerformAccesskey(PRBool aKeyCausesActivation,
                                      PRBool aIsTrustedEvent)
 {
   if (!aKeyCausesActivation) {
-    nsCOMPtr<nsIContent> content = GetForContent();
+    nsCOMPtr<nsIContent> content = GetControlContent();
     if (content)
       content->PerformAccesskey(aKeyCausesActivation, aIsTrustedEvent);
   } else {
@@ -394,41 +415,37 @@ nsHTMLLabelElement::PerformAccesskey(PRBool aKeyCausesActivation,
   }
 }
 
-inline PRBool IsNonLabelFormControl(nsIContent *aContent)
-{
-  return aContent->IsNodeOfType(nsINode::eHTML_FORM_CONTROL) &&
-         aContent->Tag() != nsGkAtoms::label;
-}
-
 already_AddRefed<nsIContent>
-nsHTMLLabelElement::GetForContent()
+nsHTMLLabelElement::GetControlContent()
 {
-  nsresult rv;
-
-  // Get the element that this label is for
   nsAutoString elementId;
-  rv = GetHtmlFor(elementId);
-  if (NS_SUCCEEDED(rv) && !elementId.IsEmpty()) {
-    // We have a FOR attribute.
-    nsCOMPtr<nsIDOMDocument> domDoc;
-    GetOwnerDocument(getter_AddRefs(domDoc));
-    if (domDoc) {
-      nsCOMPtr<nsIDOMElement> domElement;
-      domDoc->GetElementById(elementId, getter_AddRefs(domElement));
-      nsIContent *result = nsnull;
-      if (domElement) {
-        CallQueryInterface(domElement, &result);
-        if (result && !IsNonLabelFormControl(result)) {
-          NS_RELEASE(result); // assigns null
-        }
-      }
-      return result;
-    }
-  } else {
-    // No FOR attribute, we are a label for our first form control element.
-    // do a depth-first traversal to look for the first form control element
+
+  if (!GetAttr(kNameSpaceID_None, nsGkAtoms::_for, elementId)) {
+    // No @for, so we are a label for our first form control element.
+    // Do a depth-first traversal to look for the first form control element.
     return GetFirstFormControl(this);
   }
+
+  // We have a @for. The id has to be linked to an element in the same document
+  // and this element should be a labelable form control.
+  nsIDocument* doc = GetCurrentDoc();
+  if (!doc) {
+    return nsnull;
+  }
+
+  nsresult rv;
+  nsIContent* content = doc->GetElementById(elementId, &rv);
+  NS_ENSURE_SUCCESS(rv, nsnull);
+  if (!content) {
+    return nsnull;
+  }
+
+  nsCOMPtr<nsIFormControl> element = do_QueryInterface(content);
+  if (element && element->IsLabelableControl()) {
+    NS_ADDREF(content);
+    return content;
+  }
+
   return nsnull;
 }
 
@@ -439,18 +456,22 @@ nsHTMLLabelElement::GetFirstFormControl(nsIContent *current)
 
   for (PRUint32 i = 0; i < numNodes; i++) {
     nsIContent *child = current->GetChildAt(i);
-    if (child) {
-      if (IsNonLabelFormControl(child)) {
-        NS_ADDREF(child);
-        return child;
-      }
+    if (!child) {
+      continue;
+    }
 
-      nsIContent* content = GetFirstFormControl(child).get();
-      if (content) {
-        return content;
-      }
+    nsCOMPtr<nsIFormControl> element = do_QueryInterface(child);
+    if (element && element->IsLabelableControl()) {
+      NS_ADDREF(child);
+      return child;
+    }
+
+    nsIContent* content = GetFirstFormControl(child).get();
+    if (content) {
+      return content;
     }
   }
 
   return nsnull;
 }
+

dom/base/nsDOMClassInfo.cpp

@@ -280,6 +280,7 @@
 #include "nsIDOMHTMLIsIndexElement.h"
 #include "nsIDOMHTMLLIElement.h"
 #include "nsIDOMHTMLLabelElement.h"
+#include "nsIDOMNSHTMLLabelElement.h"
 #include "nsIDOMHTMLLegendElement.h"
 #include "nsIDOMHTMLLinkElement.h"
 #include "nsIDOMHTMLMapElement.h"
@@ -2477,6 +2478,7 @@ nsDOMClassInfo::Init()
 
   DOM_CLASSINFO_MAP_BEGIN(HTMLLabelElement, nsIDOMHTMLLabelElement)
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMHTMLLabelElement)
+    DOM_CLASSINFO_MAP_ENTRY(nsIDOMNSHTMLLabelElement)
     DOM_CLASSINFO_GENERIC_HTML_MAP_ENTRIES
   DOM_CLASSINFO_MAP_END
 

dom/interfaces/html/Makefile.in

@@ -128,6 +128,7 @@ XPIDLSRCS = 					\
 	nsIDOMNSHTMLHRElement.idl		\
 	nsIDOMNSHTMLImageElement.idl		\
 	nsIDOMNSHTMLInputElement.idl		\
+	nsIDOMNSHTMLLabelElement.idl		\
 	nsIDOMNSHTMLOptionCollectn.idl		\
 	nsIDOMNSHTMLOptionElement.idl		\
 	nsIDOMNSHTMLSelectElement.idl		\

dom/interfaces/html/nsIDOMNSHTMLLabelElement.idl

@@ -0,0 +1,46 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is mozilla.org code.
+ *
+ * The Initial Developer of the Original Code is Mozilla Foundation
+ * Portions created by the Initial Developer are Copyright (C) 2010
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Mounir Lamouri <mounir.lamouri@mozilla.com> (original author)
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either of the GNU General Public License Version 2 or later (the "GPL"),
+ * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#include "domstubs.idl"
+
+interface nsIDOMHTMLElement;
+
+[scriptable, uuid(93e8a513-6cef-44c3-875e-1bce83c3b1f0)]
+interface nsIDOMNSHTMLLabelElement : nsISupports
+{
+  readonly attribute nsIDOMHTMLElement     control;
+};