Bug 1460509 - part 9: Make TextEditRules::WillSetText() return NS_ERROR_EDITOR_DESTROYED if it causes destroying the editor r=m_kato

MozReview-Commit-ID: 9ksPugTVVqh

--HG--
extra : rebase_source : 25089af1de8fc8429118e773df25ec2788cb75b9

editor/libeditor/TextEditRules.cpp

@@ -906,6 +906,9 @@ TextEditRules::WillSetText(bool* aCancel,
     nsresult rv =
       TextEditorRef().InsertNodeWithTransaction(
                         *newNode, EditorRawDOMPoint(rootElement, 0));
+    if (NS_WARN_IF(!CanHandleEditAction())) {
+      return NS_ERROR_EDITOR_DESTROYED;
+    }
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
     }
@@ -925,6 +928,9 @@ TextEditRules::WillSetText(bool* aCancel,
   // for performance
   nsresult rv = TextEditorRef().SetTextImpl(SelectionRef(), tString,
                                             *curNode->GetAsText());
+  if (NS_WARN_IF(!CanHandleEditAction())) {
+    return NS_ERROR_EDITOR_DESTROYED;
+  }
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }

editor/libeditor/TextEditRules.h

@@ -139,10 +139,20 @@ protected:
 
   nsresult WillInsertBreak(bool* aCancel, bool* aHandled, int32_t aMaxLength);
 
-  nsresult WillSetText(bool* aCancel,
-                       bool* aHandled,
-                       const nsAString* inString,
-                       int32_t aMaxLength);
+  /**
+   * Called before setting text to the text editor.
+   * This method may actually set text to it.  Therefore, this might cause
+   * destroying the text editor.
+   *
+   * @param aCancel             Returns true if the operation is canceled.
+   * @param aHandled            Returns true if the edit action is handled.
+   * @param inString            String to be set.
+   * @param aMaxLength          The maximum string length which the text editor
+   *                            allows to set.
+   */
+  MOZ_MUST_USE nsresult
+  WillSetText(bool* aCancel, bool* aHandled,
+              const nsAString* inString, int32_t aMaxLength);
 
   void WillInsert(bool* aCancel);