Bug 1365092 - Move side effects of SetAttr and ParseAttribute to BeforeSetAttr and AfterSetAttr

* Moves side effects of nsGenericHTMLElement and Element's SetAttr, UnsetAttr, and ParseAttribute functions to the corresponding BeforeSetAttr and AfterSetAttr functions
* Moves side effects of HTMLAnchorElement's SetAttr, UnsetAttr, and ParseAttribute functions to the corresponding BeforeSetAttr and AfterSetAttr functions
* Moves side effects of HTMLImageElement's SetAttr function to the corresponding BeforeSetAttr and AfterSetAttr functions
* Moves side effects of SetAttr, UnsetAttr, and ParseAttribute functions to BeforeSetAttr and AfterSetAttr

Tag #1375

1 files changed, 60 insertions, 6 deletions

diff --git a/dom/base/Element.h b/dom/base/Element.h
index 6f60c9ad0..df0dbcc45 100644
--- a/dom/base/Element.h
+++ b/dom/base/Element.h
@@ -523,6 +523,7 @@ public:
   already_AddRefed<mozilla::dom::NodeInfo>
   GetExistingAttrNameFromQName(const nsAString& aStr) const;
 
+  MOZ_ALWAYS_INLINE  // Avoid a crashy hook from Avast 10 Beta (Bug 1058131)
   nsresult SetAttr(int32_t aNameSpaceID, nsIAtom* aName,
                    const nsAString& aValue, bool aNotify)
   {
@@ -1378,14 +1379,9 @@ protected:
    *        will be null.
    * @param aNotify Whether we plan to notify document observers.
    */
-  // Note that this is inlined so that when subclasses call it it gets
-  // inlined.  Those calls don't go through a vtable.
   virtual nsresult BeforeSetAttr(int32_t aNamespaceID, nsIAtom* aName,
                                  const nsAttrValueOrString* aValue,
-                                 bool aNotify)
-  {
-    return NS_OK;
-  }
+                                 bool aNotify);
 
   /**
    * Hook that is called by Element::SetAttr to allow subclasses to
@@ -1413,6 +1409,64 @@ protected:
   }
 
   /**
+   * This function shall be called just before the id attribute changes. It will
+   * be called after BeforeSetAttr. If the attribute being changed is not the id
+   * attribute, this function does nothing. Otherwise, it will remove the old id
+   * from the document's id cache.
+   *
+   * This must happen after BeforeSetAttr (rather than during) because the
+   * the subclasses' calls to BeforeSetAttr may notify on state changes. If they
+   * incorrectly determine whether the element had an id, the element may not be
+   * restyled properly.
+   *
+   * @param aNamespaceID the namespace of the attr being set
+   * @param aName the localname of the attribute being set
+   * @param aValue the new id value. Will be null if the id is being unset.
+   */
+  void PreIdMaybeChange(int32_t aNamespaceID, nsIAtom* aName,
+                        const nsAttrValueOrString* aValue);
+
+  /**
+   * This function shall be called just after the id attribute changes. It will
+   * be called before AfterSetAttr. If the attribute being changed is not the id
+   * attribute, this function does nothing. Otherwise, it will add the new id to
+   * the document's id cache and properly set the ElementHasID flag.
+   *
+   * This must happen before AfterSetAttr (rather than during) because the
+   * the subclasses' calls to AfterSetAttr may notify on state changes. If they
+   * incorrectly determine whether the element now has an id, the element may
+   * not be restyled properly.
+   *
+   * @param aNamespaceID the namespace of the attr being set
+   * @param aName the localname of the attribute being set
+   * @param aValue the new id value. Will be null if the id is being unset.
+   */
+  void PostIdMaybeChange(int32_t aNamespaceID, nsIAtom* aName,
+                         const nsAttrValue* aValue);
+
+  /**
+   * Usually, setting an attribute to the value that it already has results in
+   * no action. However, in some cases, setting an attribute to its current
+   * value should have the effect of, for example, forcing a reload of
+   * network data. To address that, this function will be called in this
+   * situation to allow the handling of such a case.
+   *
+   * @param aNamespaceID the namespace of the attr being set
+   * @param aName the localname of the attribute being set
+   * @param aValue the value it's being set to represented as either a string or
+   *        a parsed nsAttrValue.
+   * @param aNotify Whether we plan to notify document observers.
+   */
+  // Note that this is inlined so that when subclasses call it it gets
+  // inlined.  Those calls don't go through a vtable.
+  virtual nsresult OnAttrSetButNotChanged(int32_t aNamespaceID, nsIAtom* aName,
+                                          const nsAttrValueOrString& aValue,
+                                          bool aNotify)
+  {
+    return NS_OK;
+  }
+
+  /**
    * Hook to allow subclasses to produce a different EventListenerManager if
    * needed for attachment of attribute-defined handlers
    */