[InputEvent] Move 'beforeinput' logic into |CompositeEditCommand::willApplyEditing()| (3/3)

third_party/WebKit/Source/core/page/DragController.cpp

 /*
  * Copyright (C) 2007, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 583 matching lines @@
       const DeleteMode deleteMode =
           innerFrame->editor().smartInsertDeleteEnabled() ? DeleteMode::Smart
                                                           : DeleteMode::Simple;
       const InsertMode insertMode =
           (deleteMode == DeleteMode::Smart &&
            innerFrame->selection().granularity() == WordGranularity &&
            dragData->canSmartReplace())
               ? InsertMode::Smart
               : InsertMode::Simple;
 
-      if (!innerFrame->editor().deleteSelectionAfterDraggingWithEvents(

[chongz, 2016/12/20 23:27:53]

Removed, drag deletion are covered by |DeleteSelectionCommand =>
willApplyEditing()|.

-              innerFrame->editor().findEventTargetFromSelection(), deleteMode,
-              dragCaret.base()))
+      innerFrame->editor().deleteSelectionWithSmartDelete(
+          EditCommandSource::kMenuOrKeyBinding, deleteMode,
+          InputEvent::InputType::DeleteByDrag, dragCaret.base());
+
+      // 'beforeinput' event handler may destroy drop frame.

[Xiaocheng, 2016/12/21 02:56:39]

Is it just 'beforeinput'?

In fact is it a bug that the current drag&drop doesn't abort even if other
events fired by DeleteSelectionCommand destroys the frame?

[chongz, 2016/12/21 23:59:24]

I've tested 'input' and it won't crash, so I think it's only 'beforeinput'.

Other events are dispatched through |dispatchScopedEvent()| and my debug log
told me |ScopedEventQueue::instance()->shouldQueueEvents()| was true (however
I'm not sure where the scope starts). 

We have to use |dispatchEvent()| for 'beforeinput' as JS might prevent default.

+      if (innerFrame->document()->frame() != innerFrame ||
+          !element->isConnected())
         return false;
 
       innerFrame->selection().setSelection(
           SelectionInDOMTree::Builder()
               .setBaseAndExtent(EphemeralRange(range))
               .build());
       if (innerFrame->selection().isAvailable()) {
         DCHECK(m_documentUnderMouse);
-        if (!innerFrame->editor().replaceSelectionAfterDraggingWithEvents(

[chongz, 2016/12/20 23:27:53]

Removed, drop replacing are covered by |ReplaceSelectionCommand =>
willApplyEditing()|.

-                element, dragData, fragment, range, insertMode, dragSourceType))
-          return false;
+        innerFrame->editor().replaceSelectionAfterDragging(fragment, insertMode,
+                                                           dragSourceType);
       }
     } else {
       if (setSelectionToDragCaret(innerFrame, dragCaret, range, point)) {
         DCHECK(m_documentUnderMouse);
-        if (!innerFrame->editor().replaceSelectionAfterDraggingWithEvents(

[chongz, 2016/12/20 23:27:53]

Removed, drop replacing are covered by |ReplaceSelectionCommand =>
willApplyEditing()|.

-                element, dragData, fragment, range,
-                dragData->canSmartReplace() ? InsertMode::Smart
-                                            : InsertMode::Simple,
-                dragSourceType))
-          return false;
+        innerFrame->editor().replaceSelectionAfterDragging(
+            fragment, dragData->canSmartReplace() ? InsertMode::Smart
+                                                  : InsertMode::Simple,
+            dragSourceType);
       }
     }
   } else {
     String text = dragData->asPlainText();
     if (text.isEmpty())
       return false;
 
     if (setSelectionToDragCaret(innerFrame, dragCaret, range, point)) {
       DCHECK(m_documentUnderMouse);
-      if (!innerFrame->editor().replaceSelectionAfterDraggingWithEvents(

[chongz, 2016/12/20 23:27:53]

Removed, drop replacing are covered by |ReplaceSelectionCommand =>
willApplyEditing()|.

-              element, dragData,
-              createFragmentFromText(EphemeralRange(range), text), range,
-              InsertMode::Simple, DragSourceType::PlainTextSource))
-        return false;
+      innerFrame->editor().replaceSelectionAfterDragging(
+          createFragmentFromText(EphemeralRange(range), text),
+          InsertMode::Simple, DragSourceType::PlainTextSource);
     }
   }
 

[Xiaocheng, 2016/12/21 02:56:39]

We should check whether the frame is destroyed here, and abort if so.

[chongz, 2016/12/21 23:59:24]

Done.

   if (rootEditableElement) {
     if (LocalFrame* frame = rootEditableElement->document().frame()) {
       frame->eventHandler().updateDragStateAfterEditDragIfNeeded(
           rootEditableElement);
     }
   }
 
   return true;
 }
 
@@ skipping 569 matching lines @@
 }
 
 DEFINE_TRACE(DragController) {
   visitor->trace(m_page);
   visitor->trace(m_documentUnderMouse);
   visitor->trace(m_dragInitiator);
   visitor->trace(m_fileInputElementUnderMouse);
 }
 
 }  // namespace blink