Bug 768756 part 2 - Make nsComputedDOMStyle Init infallible and merge into constructor; r=bz

content/smil/nsSMILCSSProperty.cpp

@@ -17,7 +17,7 @@ using namespace mozilla::dom;
 
 // Helper function
 static bool
-GetCSSComputedValue(nsIContent* aElem,
+GetCSSComputedValue(Element* aElem,
                     nsCSSProperty aPropID,
                     nsAString& aResult)
 {
@@ -40,16 +40,11 @@ GetCSSComputedValue(nsIContent* aElem,
     return false;
   }
 
-  nsRefPtr<nsComputedDOMStyle> computedStyle;
-  nsCOMPtr<nsIDOMElement> domElement(do_QueryInterface(aElem));
-  nsresult rv = NS_NewComputedDOMStyle(domElement, EmptyString(), shell,
-                                       getter_AddRefs(computedStyle));
+  nsRefPtr<nsComputedDOMStyle> computedStyle =
+    NS_NewComputedDOMStyle(aElem, EmptyString(), shell);
 
-  if (NS_SUCCEEDED(rv)) {
-    computedStyle->GetPropertyValue(aPropID, aResult);
-    return true;
-  }
-  return false;
+  computedStyle->GetPropertyValue(aPropID, aResult);
+  return true;
 }
 
 // Class Methods

dom/base/nsGlobalWindow.cpp

@@ -8176,10 +8176,10 @@ nsGlobalWindow::GetComputedStyle(nsIDOMElement* aElt,
     return NS_OK;
   }
 
-  nsRefPtr<nsComputedDOMStyle> compStyle;
-  nsresult rv = NS_NewComputedDOMStyle(aElt, aPseudoElt, presShell,
-                                       getter_AddRefs(compStyle));
-  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<dom::Element> element = do_QueryInterface(aElt);
+  NS_ENSURE_TRUE(element, NS_ERROR_FAILURE);
+  nsRefPtr<nsComputedDOMStyle> compStyle =
+    NS_NewComputedDOMStyle(element, aPseudoElt, presShell);
 
   *aReturn = compStyle.forget().get();
 

layout/style/nsComputedDOMStyle.cpp

@@ -60,10 +60,9 @@ using namespace mozilla::dom;
 
 static nsComputedDOMStyle *sCachedComputedDOMStyle;
 
-nsresult
-NS_NewComputedDOMStyle(nsIDOMElement *aElement, const nsAString &aPseudoElt,
-                       nsIPresShell *aPresShell,
-                       nsComputedDOMStyle **aComputedStyle)
+already_AddRefed<nsComputedDOMStyle>
+NS_NewComputedDOMStyle(dom::Element* aElement, const nsAString& aPseudoElt,
+                       nsIPresShell* aPresShell)
 {
   nsRefPtr<nsComputedDOMStyle> computedStyle;
   if (sCachedComputedDOMStyle) {
@@ -71,23 +70,17 @@ NS_NewComputedDOMStyle(nsIDOMElement *aElement, const nsAString &aPseudoElt,
     // But before we use it, re-initialize the object.
 
     // Oh yeah baby, placement new!
-    computedStyle = new (sCachedComputedDOMStyle) nsComputedDOMStyle();
+    computedStyle = new (sCachedComputedDOMStyle)
+      nsComputedDOMStyle(aElement, aPseudoElt, aPresShell);
 
     sCachedComputedDOMStyle = nsnull;
   } else {
     // No nsComputedDOMStyle cached, create a new one.
 
-    computedStyle = new nsComputedDOMStyle();
-    NS_ENSURE_TRUE(computedStyle, NS_ERROR_OUT_OF_MEMORY);
+    computedStyle = new nsComputedDOMStyle(aElement, aPseudoElt, aPresShell);
   }
 
-  nsresult rv = computedStyle->Init(aElement, aPseudoElt, aPresShell);
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  *aComputedStyle = nsnull;
-  computedStyle.swap(*aComputedStyle);
-
-  return NS_OK;
+  return computedStyle.forget();
 }
 
 static nsIFrame*
@@ -98,11 +91,46 @@ GetContainingBlockFor(nsIFrame* aFrame) {
   return aFrame->GetContainingBlock();
 }
 
-nsComputedDOMStyle::nsComputedDOMStyle()
+nsComputedDOMStyle::nsComputedDOMStyle(dom::Element* aElement,
+                                       const nsAString& aPseudoElt,
+                                       nsIPresShell* aPresShell)
   : mDocumentWeak(nsnull), mOuterFrame(nsnull),
     mInnerFrame(nsnull), mPresShell(nsnull),
     mExposeVisitedStyle(false)
 {
+  MOZ_ASSERT(aElement && aPresShell);
+
+  mDocumentWeak = do_GetWeakReference(aPresShell->GetDocument());
+
+  mContent = aElement;
+
+  if (!DOMStringIsNull(aPseudoElt) && !aPseudoElt.IsEmpty() &&
+      aPseudoElt.First() == PRUnichar(':')) {
+    // deal with two-colon forms of aPseudoElt
+    nsAString::const_iterator start, end;
+    aPseudoElt.BeginReading(start);
+    aPseudoElt.EndReading(end);
+    NS_ASSERTION(start != end, "aPseudoElt is not empty!");
+    ++start;
+    bool haveTwoColons = true;
+    if (start == end || *start != PRUnichar(':')) {
+      --start;
+      haveTwoColons = false;
+    }
+    mPseudo = do_GetAtom(Substring(start, end));
+    MOZ_ASSERT(mPseudo);
+
+    // There aren't any non-CSS2 pseudo-elements with a single ':'
+    if (!haveTwoColons &&
+        !nsCSSPseudoElements::IsCSS2PseudoElement(mPseudo)) {
+      // XXXbz I'd really rather we threw an exception or something, but
+      // the DOM spec sucks.
+      mPseudo = nsnull;
+    }
+  }
+
+  nsPresContext *presCtx = aPresShell->GetPresContext();
+  MOZ_ASSERT(presCtx);
 }
 
 
@@ -168,54 +196,6 @@ NS_IMPL_CYCLE_COLLECTING_RELEASE_WITH_DESTROY(nsComputedDOMStyle,
                                               doDestroyComputedDOMStyle(this))
 
 
-NS_IMETHODIMP
-nsComputedDOMStyle::Init(nsIDOMElement *aElement,
-                         const nsAString& aPseudoElt,
-                         nsIPresShell *aPresShell)
-{
-  NS_ENSURE_ARG_POINTER(aElement);
-  NS_ENSURE_ARG_POINTER(aPresShell);
-
-  mDocumentWeak = do_GetWeakReference(aPresShell->GetDocument());
-
-  mContent = do_QueryInterface(aElement);
-  if (!mContent) {
-    // This should not happen, all our elements support nsIContent!
-
-    return NS_ERROR_FAILURE;
-  }
-
-  if (!DOMStringIsNull(aPseudoElt) && !aPseudoElt.IsEmpty() &&
-      aPseudoElt.First() == PRUnichar(':')) {
-    // deal with two-colon forms of aPseudoElt
-    nsAString::const_iterator start, end;
-    aPseudoElt.BeginReading(start);
-    aPseudoElt.EndReading(end);
-    NS_ASSERTION(start != end, "aPseudoElt is not empty!");
-    ++start;
-    bool haveTwoColons = true;
-    if (start == end || *start != PRUnichar(':')) {
-      --start;
-      haveTwoColons = false;
-    }
-    mPseudo = do_GetAtom(Substring(start, end));
-    NS_ENSURE_TRUE(mPseudo, NS_ERROR_OUT_OF_MEMORY);
-
-    // There aren't any non-CSS2 pseudo-elements with a single ':'
-    if (!haveTwoColons &&
-        !nsCSSPseudoElements::IsCSS2PseudoElement(mPseudo)) {
-      // XXXbz I'd really rather we threw an exception or something, but
-      // the DOM spec sucks.
-      mPseudo = nsnull;
-    }
-  }
-
-  nsPresContext *presCtx = aPresShell->GetPresContext();
-  NS_ENSURE_TRUE(presCtx, NS_ERROR_FAILURE);
-
-  return NS_OK;
-}
-
 NS_IMETHODIMP
 nsComputedDOMStyle::GetPropertyValue(const nsCSSProperty aPropID,
                                      nsAString& aValue)

layout/style/nsComputedDOMStyle.h

@@ -32,15 +32,13 @@ public:
   NS_DECL_CYCLE_COLLECTION_SKIPPABLE_CLASS_AMBIGUOUS(nsComputedDOMStyle,
                                                      nsICSSDeclaration)
 
-  NS_IMETHOD Init(nsIDOMElement *aElement,
-                  const nsAString& aPseudoElt,
-                  nsIPresShell *aPresShell);
-
   NS_DECL_NSICSSDECLARATION
 
   NS_DECL_NSIDOMCSSSTYLEDECLARATION
 
-  nsComputedDOMStyle();
+  nsComputedDOMStyle(mozilla::dom::Element* aElement,
+                     const nsAString& aPseudoElt,
+                     nsIPresShell* aPresShell);
   virtual ~nsComputedDOMStyle();
 
   static void Shutdown();
@@ -511,10 +509,10 @@ private:
 #endif
 };
 
-nsresult
-NS_NewComputedDOMStyle(nsIDOMElement *aElement, const nsAString &aPseudoElt,
-                       nsIPresShell *aPresShell,
-                       nsComputedDOMStyle **aComputedStyle);
+already_AddRefed<nsComputedDOMStyle>
+NS_NewComputedDOMStyle(mozilla::dom::Element* aElement,
+                       const nsAString& aPseudoElt,
+                       nsIPresShell* aPresShell);
 
 #endif /* nsComputedDOMStyle_h__ */