Bug 738196 - Part a: introduce a common superclass for nsDOMStyleSheetList and ShadowRootStyleSheetList; r=bz

content/base/src/ShadowRoot.cpp

@@ -677,18 +677,23 @@ ShadowRootStyleSheetList::~ShadowRootStyleSheetList()
   MOZ_COUNT_DTOR(ShadowRootStyleSheetList);
 }
 
+nsCSSStyleSheet*
+ShadowRootStyleSheetList::GetItemAt(uint32_t aIndex)
+{
+  nsTArray<nsRefPtr<nsCSSStyleSheet>>* sheets =
+    mShadowRoot->mProtoBinding->GetStyleSheets();
+
+  if (!sheets) {
+    return nullptr;
+  }
+
+  return sheets->SafeElementAt(aIndex);
+}
+
 NS_IMETHODIMP
 ShadowRootStyleSheetList::Item(uint32_t aIndex, nsIDOMStyleSheet** aReturn)
 {
-  nsTArray<nsRefPtr<nsCSSStyleSheet> >* sheets =
-    mShadowRoot->mProtoBinding->GetStyleSheets();
-
-  if (sheets) {
-    NS_IF_ADDREF(*aReturn = sheets->SafeElementAt(aIndex));
-  } else {
-    *aReturn = nullptr;
-  }
-
+  NS_IF_ADDREF(*aReturn = GetItemAt(aIndex));
   return NS_OK;
 }
 

content/base/src/ShadowRoot.h

@@ -7,6 +7,7 @@
 #define mozilla_dom_shadowroot_h__
 
 #include "mozilla/dom/DocumentFragment.h"
+#include "mozilla/dom/StyleSheetList.h"
 #include "nsCOMPtr.h"
 #include "nsCycleCollectionParticipant.h"
 #include "nsTHashtable.h"
@@ -169,7 +170,7 @@ protected:
   bool mInsertionPointChanged;
 };
 
-class ShadowRootStyleSheetList : public nsIDOMStyleSheetList
+class ShadowRootStyleSheetList : public StyleSheetList
 {
 public:
   ShadowRootStyleSheetList(ShadowRoot* aShadowRoot);
@@ -181,6 +182,8 @@ public:
   // nsIDOMStyleSheetList
   NS_DECL_NSIDOMSTYLESHEETLIST
 
+  virtual nsCSSStyleSheet* GetItemAt(uint32_t aIndex) MOZ_OVERRIDE;
+
 protected:
   nsRefPtr<ShadowRoot> mShadowRoot;
 };

content/base/src/StyleSheetList.h

@@ -0,0 +1,41 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_StyleSheetList_h
+#define mozilla_dom_StyleSheetList_h
+
+#include "nsIDOMStyleSheetList.h"
+
+class nsCSSStyleSheet;
+
+namespace mozilla {
+namespace dom {
+
+class StyleSheetList : public nsIDOMStyleSheetList
+{
+public:
+  static StyleSheetList* FromSupports(nsISupports* aSupports)
+  {
+    nsIDOMStyleSheetList* list = static_cast<nsIDOMStyleSheetList*>(aSupports);
+#ifdef DEBUG
+    {
+      nsCOMPtr<nsIDOMStyleSheetList> list_qi = do_QueryInterface(aSupports);
+
+      // If this assertion fires the QI implementation for the object in
+      // question doesn't use the nsIDOMStyleSheetList pointer as the
+      // nsISupports pointer. That must be fixed, or we'll crash...
+      MOZ_ASSERT(list_qi == list, "Uh, fix QI!");
+    }
+#endif
+    return static_cast<StyleSheetList*>(list);
+  }
+
+  virtual nsCSSStyleSheet* GetItemAt(uint32_t aIndex) = 0;
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_StyleSheetList_h

content/base/src/moz.build

@@ -72,6 +72,7 @@ EXPORTS.mozilla.dom += [
     'Link.h',
     'NodeIterator.h',
     'ShadowRoot.h',
+    'StyleSheetList.h',
     'Text.h',
     'TreeWalker.h',
 ]

content/base/src/nsDocument.cpp

@@ -769,7 +769,7 @@ nsDOMStyleSheetList::GetLength(uint32_t* aLength)
   return NS_OK;
 }
 
-nsIStyleSheet*
+nsCSSStyleSheet*
 nsDOMStyleSheetList::GetItemAt(uint32_t aIndex)
 {
   if (!mDocument || aIndex >= (uint32_t)mDocument->GetNumberOfStyleSheets()) {
@@ -779,7 +779,7 @@ nsDOMStyleSheetList::GetItemAt(uint32_t aIndex)
   nsIStyleSheet *sheet = mDocument->GetStyleSheetAt(aIndex);
   NS_ASSERTION(sheet, "Must have a sheet");
 
-  return sheet;
+  return static_cast<nsCSSStyleSheet*>(sheet);
 }
 
 NS_IMETHODIMP

content/base/src/nsDocument.h

@@ -23,7 +23,6 @@
 #include "nsIDOMXMLDocument.h"
 #include "nsIDOMDocumentXBL.h"
 #include "nsStubDocumentObserver.h"
-#include "nsIDOMStyleSheetList.h"
 #include "nsIScriptGlobalObject.h"
 #include "nsIContent.h"
 #include "nsIPrincipal.h"
@@ -65,6 +64,7 @@
 #include "mozilla/EventStates.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/dom/DOMImplementation.h"
+#include "mozilla/dom/StyleSheetList.h"
 #include "nsIDOMTouchEvent.h"
 #include "nsDataHashtable.h"
 #include "mozilla/TimeStamp.h"
@@ -78,7 +78,6 @@
 #define XML_DECLARATION_BITS_STANDALONE_YES       (1 << 3)
 
 
-class nsDOMStyleSheetList;
 class nsDOMStyleSheetSetList;
 class nsIOutputStream;
 class nsDocument;
@@ -436,7 +435,7 @@ public:
   nsDocHeaderData*  mNext;
 };
 
-class nsDOMStyleSheetList : public nsIDOMStyleSheetList,
+class nsDOMStyleSheetList : public mozilla::dom::StyleSheetList,
                             public nsStubDocumentObserver
 {
 public:
@@ -454,7 +453,7 @@ public:
   // nsIMutationObserver
   NS_DECL_NSIMUTATIONOBSERVER_NODEWILLBEDESTROYED
 
-  nsIStyleSheet* GetItemAt(uint32_t aIndex);
+  virtual nsCSSStyleSheet* GetItemAt(uint32_t aIndex) MOZ_OVERRIDE;
 
 protected:
   int32_t       mLength;

dom/base/nsDOMClassInfo.cpp

@@ -3686,10 +3686,9 @@ nsISupports*
 nsStyleSheetListSH::GetItemAt(nsISupports *aNative, uint32_t aIndex,
                               nsWrapperCache **aCache, nsresult *rv)
 {
-  nsIDOMStyleSheetList* list = static_cast<nsIDOMStyleSheetList*>(aNative);
-  nsCOMPtr<nsIDOMStyleSheet> sheet;
-  list->Item(aIndex, getter_AddRefs(sheet));
-  return sheet;
+  StyleSheetList* list = StyleSheetList::FromSupports(aNative);
+  nsIDOMStyleSheet* item = list->GetItemAt(aIndex);
+  return item;
 }