bug 512260 - part 5 - make nsCursorImage::mImage private, add getter/setter, and lock images in the setter.r=dbaron,a=blocker

layout/generic/nsFrame.cpp

@@ -6240,10 +6240,10 @@ void nsFrame::FillCursorInformationFromStyle(const nsStyleUserInterface* ui,
                  *item_end = ui->mCursorArray + ui->mCursorArrayLength;
        item < item_end; ++item) {
     PRUint32 status;
-    nsresult rv = item->mImage->GetImageStatus(&status);
+    nsresult rv = item->GetImage()->GetImageStatus(&status);
     if (NS_SUCCEEDED(rv) && (status & imgIRequest::STATUS_LOAD_COMPLETE)) {
       // This is the one we want
-      item->mImage->GetImage(getter_AddRefs(aCursor.mContainer));
+      item->GetImage()->GetImage(getter_AddRefs(aCursor.mContainer));
       aCursor.mHaveHotspot = item->mHaveHotspot;
       aCursor.mHotspotX = item->mHotspotX;
       aCursor.mHotspotY = item->mHotspotY;

layout/style/nsComputedDOMStyle.cpp

@@ -2771,7 +2771,7 @@ nsComputedDOMStyle::DoGetCursor(nsIDOMCSSValue** aValue)
     }
 
     nsCOMPtr<nsIURI> uri;
-    item->mImage->GetURI(getter_AddRefs(uri));
+    item->GetImage()->GetURI(getter_AddRefs(uri));
 
     nsROCSSPrimitiveValue *val = GetROCSSPrimitiveValue();
     if (!val || !itemList->AppendCSSValue(val)) {

layout/style/nsRuleNode.cpp

@@ -3831,7 +3831,7 @@ nsRuleNode::ComputeUserInterfaceData(void* aStartStruct,
             nsCSSValue::Array *arr = list2->mValue.GetArrayValue();
             imgIRequest *req = arr->Item(0).GetImageValue();
             if (req) {
-              item->mImage = req;
+              item->SetImage(req);
               if (arr->Item(1).GetUnit() != eCSSUnit_Null) {
                 item->mHaveHotspot = PR_TRUE;
                 item->mHotspotX = arr->Item(1).GetFloatValue(),

layout/style/nsStyleStruct.cpp

@@ -2605,6 +2605,32 @@ nsCursorImage::nsCursorImage()
 {
 }
 
+nsCursorImage::nsCursorImage(const nsCursorImage& aOther)
+  : mHaveHotspot(aOther.mHaveHotspot)
+  , mHotspotX(aOther.mHotspotX)
+  , mHotspotY(aOther.mHotspotY)
+{
+  SetImage(aOther.GetImage());
+}
+
+nsCursorImage::~nsCursorImage()
+{
+  SetImage(nsnull);
+}
+
+nsCursorImage&
+nsCursorImage::operator=(const nsCursorImage& aOther)
+{
+  if (this != &aOther) {
+    mHaveHotspot = aOther.mHaveHotspot;
+    mHotspotX = aOther.mHotspotX;
+    mHotspotY = aOther.mHotspotY;
+    SetImage(aOther.GetImage());
+  }
+
+  return *this;
+}
+
 nsStyleUserInterface::nsStyleUserInterface(void) 
 { 
   MOZ_COUNT_CTOR(nsStyleUserInterface);

layout/style/nsStyleStruct.h

@@ -1729,11 +1729,32 @@ struct nsStyleUIReset {
 };
 
 struct nsCursorImage {
-  nsCOMPtr<imgIRequest> mImage;
   PRBool mHaveHotspot;
   float mHotspotX, mHotspotY;
 
   nsCursorImage();
+  nsCursorImage(const nsCursorImage& aOther);
+  ~nsCursorImage();
+
+  nsCursorImage& operator=(const nsCursorImage& aOther);
+  /*
+   * We hide mImage and force access through the getter and setter so that we
+   * can lock the images we use. Cursor images are likely to be small, so we
+   * don't care about discarding them. See bug 512260.
+   * */
+  void SetImage(imgIRequest *aImage) {
+    if (mImage)
+      mImage->UnlockImage();
+    mImage = aImage;
+    if (mImage)
+      mImage->LockImage();
+  }
+  imgIRequest* GetImage() const {
+    return mImage;
+  }
+
+private:
+  nsCOMPtr<imgIRequest> mImage;
 };
 
 struct nsStyleUserInterface {