Bug 1297393 - Make passing of subject principals to webidl entry points explicit - part 2 - DataTransferItem, r=ehsan

dom/events/DataTransferItem.cpp

@@ -238,21 +238,18 @@ DataTransferItem::FillInExternalData()
 }
 
 already_AddRefed<File>
-DataTransferItem::GetAsFile(ErrorResult& aRv)
+DataTransferItem::GetAsFile(const Maybe<nsIPrincipal*>& aSubjectPrincipal,
+                            ErrorResult& aRv)
 {
-  return GetAsFileWithPrincipal(nsContentUtils::SubjectPrincipal(), aRv);
-}
+  MOZ_ASSERT(aSubjectPrincipal.isSome());
 
-already_AddRefed<File>
-DataTransferItem::GetAsFileWithPrincipal(nsIPrincipal* aPrincipal, ErrorResult& aRv)
-{
   if (mKind != KIND_FILE) {
     return nullptr;
   }
 
   // This is done even if we have an mCachedFile, as it performs the necessary
   // permissions checks to ensure that we are allowed to access this type.
-  nsCOMPtr<nsIVariant> data = Data(aPrincipal, aRv);
+  nsCOMPtr<nsIVariant> data = Data(aSubjectPrincipal.value(), aRv);
   if (NS_WARN_IF(!data || aRv.Failed())) {
     return nullptr;
   }
@@ -286,16 +283,12 @@ DataTransferItem::GetAsFileWithPrincipal(nsIPrincipal* aPrincipal, ErrorResult&
 }
 
 already_AddRefed<FileSystemEntry>
-DataTransferItem::GetAsEntry(ErrorResult& aRv)
+DataTransferItem::GetAsEntry(const Maybe<nsIPrincipal*>& aSubjectPrincipal,
+                             ErrorResult& aRv)
 {
-  return GetAsEntryWithPrincipal(nsContentUtils::SubjectPrincipal(), aRv);
-}
+  MOZ_ASSERT(aSubjectPrincipal.isSome());
 
-already_AddRefed<FileSystemEntry>
-DataTransferItem::GetAsEntryWithPrincipal(nsIPrincipal* aPrincipal,
-                                          ErrorResult& aRv)
-{
-  RefPtr<File> file = GetAsFileWithPrincipal(aPrincipal, aRv);
+  RefPtr<File> file = GetAsFile(aSubjectPrincipal, aRv);
   if (NS_WARN_IF(aRv.Failed()) || !file) {
     return nullptr;
   }
@@ -393,8 +386,11 @@ DataTransferItem::CreateFileFromInputStream(nsIInputStream* aStream)
 
 void
 DataTransferItem::GetAsString(FunctionStringCallback* aCallback,
+                              const Maybe<nsIPrincipal*>& aSubjectPrincipal,
                               ErrorResult& aRv)
 {
+  MOZ_ASSERT(aSubjectPrincipal.isSome());
+
   if (!aCallback || mKind != KIND_STRING) {
     return;
   }
@@ -402,7 +398,7 @@ DataTransferItem::GetAsString(FunctionStringCallback* aCallback,
   // Theoretically this should be done inside of the runnable, as it might be an
   // expensive operation on some systems, however we wouldn't get access to the
   // NS_ERROR_DOM_SECURITY_ERROR messages which may be raised by this method.
-  nsCOMPtr<nsIVariant> data = Data(nsContentUtils::SubjectPrincipal(), aRv);
+  nsCOMPtr<nsIVariant> data = Data(aSubjectPrincipal.value(), aRv);
   if (NS_WARN_IF(!data || aRv.Failed())) {
     return;
   }

dom/events/DataTransferItem.h

@@ -50,7 +50,9 @@ public:
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
 
   // NOTE: This accesses the subject principal, and should not be called from C++
-  void GetAsString(FunctionStringCallback* aCallback, ErrorResult& aRv);
+  void GetAsString(FunctionStringCallback* aCallback,
+                   const Maybe<nsIPrincipal*>& aPrincipal,
+                   ErrorResult& aRv);
 
   void GetKind(nsAString& aKind) const
   {
@@ -82,15 +84,11 @@ public:
     mKind = aKind;
   }
 
-  // NOTE: This accesses the subject principal, and should not be called from C++
-  already_AddRefed<File> GetAsFile(ErrorResult& aRv);
-  already_AddRefed<File> GetAsFileWithPrincipal(nsIPrincipal* aPrincipal,
-                                                ErrorResult& aRv);
+  already_AddRefed<File>
+  GetAsFile(const Maybe<nsIPrincipal*>& aSubjectPrincipal, ErrorResult& aRv);
 
-  // NOTE: This accesses the subject principal, and should not be called from C++
-  already_AddRefed<FileSystemEntry> GetAsEntry(ErrorResult& aRv);
-  already_AddRefed<FileSystemEntry> GetAsEntryWithPrincipal(nsIPrincipal* aPrincipal,
-                                                            ErrorResult& aRv);
+  already_AddRefed<FileSystemEntry>
+  GetAsEntry(const Maybe<nsIPrincipal*>& aSubjectPrincipal, ErrorResult& aRv);
 
   DataTransfer* GetParentObject() const
   {

dom/events/DataTransferItemList.cpp

@@ -557,7 +557,7 @@ DataTransferItemList::GenerateFiles(FileList* aFiles,
     }
 
     if (item->Kind() == DataTransferItem::KIND_FILE) {
-      RefPtr<File> file = item->GetAsFileWithPrincipal(aFilesPrincipal, rv);
+      RefPtr<File> file = item->GetAsFile(Some(aFilesPrincipal), rv);
       if (NS_WARN_IF(rv.Failed() || !file)) {
         continue;
       }

dom/webidl/DataTransferItem.webidl

@@ -10,15 +10,16 @@
 interface DataTransferItem {
   readonly attribute DOMString kind;
   readonly attribute DOMString type;
-  [Throws]
+  [Throws, NeedsSubjectPrincipal]
   void getAsString(FunctionStringCallback? _callback);
-  [Throws]
+  [Throws, NeedsSubjectPrincipal]
   File? getAsFile();
 };
 
 callback FunctionStringCallback = void (DOMString data);
 
 partial interface DataTransferItem {
-  [Pref="dom.webkitBlink.filesystem.enabled", BinaryName="getAsEntry", Throws]
+  [Pref="dom.webkitBlink.filesystem.enabled", BinaryName="getAsEntry", Throws,
+   NeedsSubjectPrincipal]
   FileSystemEntry? webkitGetAsEntry();
 };