Bug 615977: Make nsCSSValue::BufferFromString() return an already_AddRefed pointer. r=dbaron a=roc

--HG--
extra : rebase_source : b4048d8fbde522f05a01df693887e0e26a5afb97

content/html/content/src/nsGenericHTMLElement.cpp

@@ -1957,16 +1957,15 @@ nsGenericHTMLElement::MapBackgroundInto(const nsMappedAttributes* aAttributes,
           // Note that this should generally succeed here, due to the way
           // |spec| is created.  Maybe we should just add an nsStringBuffer
           // accessor on nsAttrValue?
-          nsStringBuffer* buffer = nsCSSValue::BufferFromString(spec);
-          if (NS_LIKELY(buffer != 0)) {
+          nsRefPtr<nsStringBuffer> buffer = nsCSSValue::BufferFromString(spec);
+          if (NS_LIKELY(buffer)) {
             // XXXbz it would be nice to assert that doc->NodePrincipal() is
             // the same as the principal of the node (which we'd need to store
             // in the mapped attrs or something?)
             nsCSSValue::Image *img =
               new nsCSSValue::Image(uri, buffer, doc->GetDocumentURI(),
                                     doc->NodePrincipal(), doc);
-            buffer->Release();
-            if (NS_LIKELY(img != 0)) {
+            if (NS_LIKELY(img)) {
               nsCSSValueList* list =
                 aData->mColorData->mBackImage.SetListValue();
               list->mValue.SetImageValue(img);

content/smil/nsSMILMappedAttribute.cpp

@@ -126,7 +126,8 @@ nsSMILMappedAttribute::SetAnimValue(const nsSMILValue& aValue)
   }
 
   // Set the string as this mapped attribute's animated value.
-  nsStringBuffer* valStrBuf = nsCSSValue::BufferFromString(nsString(valStr));
+  nsStringBuffer* valStrBuf =
+    nsCSSValue::BufferFromString(nsString(valStr)).get();
   nsRefPtr<nsIAtom> attrName = GetAttrNameAtom();
   nsresult rv = mElement->SetProperty(SMIL_MAPPED_ATTR_ANIMVAL,
                                       attrName, valStrBuf,

layout/style/nsCSSParser.cpp

@@ -4653,15 +4653,16 @@ CSSParserImpl::SetValueToURL(nsCSSValue& aValue, const nsString& aURL)
   nsCOMPtr<nsIURI> uri;
   NS_NewURI(getter_AddRefs(uri), aURL, nsnull, mBaseURI);
 
-  nsStringBuffer* buffer = nsCSSValue::BufferFromString(aURL);
+  nsRefPtr<nsStringBuffer> buffer(nsCSSValue::BufferFromString(aURL));
   if (NS_UNLIKELY(!buffer)) {
     mScanner.SetLowLevelError(NS_ERROR_OUT_OF_MEMORY);
     return PR_FALSE;
   }
+
+  // Note: urlVal retains its own reference to |buffer|.
   nsCSSValue::URL *urlVal =
     new nsCSSValue::URL(uri, buffer, mSheetURI, mSheetPrincipal);
 
-  buffer->Release();
   if (NS_UNLIKELY(!urlVal)) {
     mScanner.SetLowLevelError(NS_ERROR_OUT_OF_MEMORY);
     return PR_FALSE;

layout/style/nsCSSValue.cpp

@@ -81,7 +81,7 @@ nsCSSValue::nsCSSValue(const nsString& aValue, nsCSSUnit aUnit)
 {
   NS_ABORT_IF_FALSE(UnitHasStringValue(), "not a string value");
   if (UnitHasStringValue()) {
-    mValue.mString = BufferFromString(aValue);
+    mValue.mString = BufferFromString(aValue).get();
     if (NS_UNLIKELY(!mValue.mString)) {
       // XXXbz not much we can do here; just make sure that our promise of a
       // non-null mValue.mString holds for string units.
@@ -356,7 +356,7 @@ void nsCSSValue::SetStringValue(const nsString& aValue,
   mUnit = aUnit;
   NS_ABORT_IF_FALSE(UnitHasStringValue(), "not a string unit");
   if (UnitHasStringValue()) {
-    mValue.mString = BufferFromString(aValue);
+    mValue.mString = BufferFromString(aValue).get();
     if (NS_UNLIKELY(!mValue.mString)) {
       // XXXbz not much we can do here; just make sure that our promise of a
       // non-null mValue.mString holds for string units.
@@ -598,7 +598,7 @@ nsCSSValue::EqualsFunction(nsCSSKeyword aFunctionId) const
 }
 
 // static
-nsStringBuffer*
+already_AddRefed<nsStringBuffer>
 nsCSSValue::BufferFromString(const nsString& aValue)
 {
   nsStringBuffer* buffer = nsStringBuffer::FromString(aValue);
@@ -608,6 +608,8 @@ nsCSSValue::BufferFromString(const nsString& aValue)
   }
   
   PRUnichar length = aValue.Length();
+
+  // NOTE: Alloc prouduces a new, already-addref'd (refcnt = 1) buffer.
   buffer = nsStringBuffer::Alloc((length + 1) * sizeof(PRUnichar));
   if (NS_LIKELY(buffer != 0)) {
     PRUnichar* data = static_cast<PRUnichar*>(buffer->Data());

layout/style/nsCSSValue.h

@@ -440,7 +440,8 @@ public:
 
   // Returns an already addrefed buffer.  Can return null on allocation
   // failure.
-  static nsStringBuffer* BufferFromString(const nsString& aValue);
+  static already_AddRefed<nsStringBuffer>
+    BufferFromString(const nsString& aValue);
 
   struct URL {
     // Methods are not inline because using an nsIPrincipal means requiring

layout/style/nsStyleAnimation.cpp

@@ -2844,7 +2844,7 @@ nsStyleAnimation::Value::SetUnparsedStringValue(const nsString& aString)
 {
   FreeValue();
   mUnit = eUnit_UnparsedString;
-  mValue.mString = nsCSSValue::BufferFromString(aString);
+  mValue.mString = nsCSSValue::BufferFromString(aString).get();
   if (NS_UNLIKELY(!mValue.mString)) {
     // not much we can do here; just make sure that our promise of a
     // non-null mValue.mString holds for string units.