Selection API: extend() should operate DOM Ranges.

third_party/WebKit/Source/core/editing/DOMSelection.cpp

 /*
  * Copyright (C) 2007, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * 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.
@@ skipping 63 matching lines @@
   return frame()->selection().selection();
 }
 
 bool DOMSelection::isBaseFirstInSelection() const {
   DCHECK(frame());
   const SelectionInDOMTree& selection =
       frame()->selection().selectionInDOMTree();
   return selection.base() <= selection.extent();
 }
 
+const Position& DOMSelection::anchorPosition() const {
+  DCHECK(frame());
+  return frame()->selection().selectionInDOMTree().base();
+}
+
+const Position& DOMSelection::focusPosition() const {
+  DCHECK(frame());
+  return frame()->selection().selectionInDOMTree().extent();
+}
+
+// TODO(tkent): Following four functions based on VisibleSelection should be
+// removed.
 static Position anchorPosition(const VisibleSelection& selection) {
   Position anchor =
       selection.isBaseFirst() ? selection.start() : selection.end();
   return anchor.parentAnchoredEquivalent();
 }
 
 static Position focusPosition(const VisibleSelection& selection) {
   Position focus =
       selection.isBaseFirst() ? selection.end() : selection.start();
   return focus.parentAnchoredEquivalent();
@@ skipping 304 matching lines @@
   // needs to be audited.  See http://crbug.com/590369 for more details.
   frame()->document()->updateStyleAndLayoutIgnorePendingStylesheets();
 
   frame()->selection().modify(alter, direction, granularity);
 }
 
 void DOMSelection::extend(Node* node,
                           int offset,
                           ExceptionState& exceptionState) {
   DCHECK(node);
+  // https://www.w3.org/TR/selection-api/#dom-selection-extend
 
+  // 2. If the context object is empty, throw an InvalidStateError exception and
+  // abort these steps.
   if (rangeCount() == 0) {
     exceptionState.throwDOMException(
         InvalidStateError, "This Selection object doesn't have any Ranges.");
     return;
   }
 
   if (offset < 0) {
     exceptionState.throwDOMException(
         IndexSizeError, String::number(offset) + " is not a valid offset.");
     return;
   }
   Range::checkNodeWOffset(node, offset, exceptionState);
   if (exceptionState.hadException())
     return;
 
+  // 1. If node's root is not the document associated with the context object,
+  // abort these steps.
   if (!isValidForPosition(node))
     return;
 
+  // 3. Let oldAnchor and oldFocus be the context object's anchor and focus, and
+  // let newFocus be the boundary point (node, offset).
+  const Position& oldAnchor = anchorPosition();
+  DCHECK(!oldAnchor.isNull());
+  Position newFocus(node, offset);

[yoichio, 2017/02/16 07:26:05]

Could you declare |const Position newFocus| ?

[tkent, 2017/02/16 08:14:38]

Yes, done.

+
   clearCachedRangeIfSelectionOfDocument();
-  const Position& base = frame()->selection().base();
-  if (base.isNull()) {
-    // TODO(editing-dev): We should throw |InvalidStateError| if selection is
-    // none to follow the spec.
+
+  // 4. Let newRange be a new range.
+  Range* newRange = Range::create(*frame()->document());
+
+  // 5. If node's root is not the same as the context object's range's root, set
+  // newRange's start and end to newFocus.
+  // E.g. oldAnchor might point in shadow Text node in TextControlElement.
+  if (oldAnchor.anchorNode()->treeRoot() != node->treeRoot()) {
+    newRange->setStart(node, offset);
+    newRange->setEnd(node, offset);
+
+  } else if (oldAnchor <= newFocus) {
+    // 6. Otherwise, if oldAnchor is before or equal to newFocus, set newRange's
+    // start to oldAnchor, then set its end to newFocus.
+    newRange->setStart(oldAnchor.anchorNode(),
+                       oldAnchor.offsetInContainerNode());
+    newRange->setEnd(node, offset);
+
+  } else {
+    // 7. Otherwise, set newRange's start to newFocus, then set its end to
+    // oldAnchor.
+    newRange->setStart(node, offset);
+    newRange->setEnd(oldAnchor.anchorNode(), oldAnchor.offsetInContainerNode());
+  }
+
+  // 8. Set the context object's range to newRange.

[yoichio, 2017/02/16 07:26:05]

How about following code to share?:

SelectionInDOMTree::Builder builder;
builder.setIsDirectional(true);
if (newRange->collapsed())
 builder.collapse(..)
else
 builder.collapse(..).extend()

setSelection(builder.build());

[tkent, 2017/02/16 08:14:38]

Done.

+  if (newRange->collapsed()) {
     frame()->selection().setSelection(SelectionInDOMTree::Builder()
-                                          .collapse(Position(node, offset))
+                                          .collapse(newFocus)
                                           .setIsDirectional(true)
                                           .build());
-    return;
+  } else {
+    frame()->selection().setSelection(SelectionInDOMTree::Builder()
+                                          .collapse(oldAnchor)
+                                          .extend(newFocus)
+                                          .setIsDirectional(true)
+                                          .build());
   }
-  frame()->selection().setSelection(SelectionInDOMTree::Builder()
-                                        .collapse(base)
-                                        .extend(Position(node, offset))
-                                        .setIsDirectional(true)
-                                        .build());
+  cacheRangeIfSelectionOfDocument(newRange);
 }
 
 Range* DOMSelection::getRangeAt(int index,
                                 ExceptionState& exceptionState) const {
   if (!isAvailable())
     return nullptr;
 
   if (index < 0 || index >= rangeCount()) {
     exceptionState.throwDOMException(
         IndexSizeError, String::number(index) + " is not a valid index.");
     return nullptr;
   }
 
   // If you're hitting this, you've added broken multi-range selection support
   DCHECK_EQ(rangeCount(), 1);
 
   if (Range* cachedRange = documentCachedRange())
     return cachedRange;
 
   Range* range = createRangeFromSelectionEditor();
   cacheRangeIfSelectionOfDocument(range);
   return range;
 }
 
 Range* DOMSelection::primaryRangeOrNull() const {
   return rangeCount() > 0 ? getRangeAt(0, ASSERT_NO_EXCEPTION) : nullptr;
 }
 
 Range* DOMSelection::createRangeFromSelectionEditor() const {
-  Position anchor = anchorPosition(visibleSelection());
+  Position anchor = blink::anchorPosition(visibleSelection());
   if (isSelectionOfDocument() && !anchor.anchorNode()->isInShadowTree())
     return frame()->selection().firstRange();
 
   Node* node = shadowAdjustedNode(anchor);
   if (!node)  // crbug.com/595100
     return nullptr;
-  Position focus = focusPosition(visibleSelection());
+  Position focus = blink::focusPosition(visibleSelection());
   if (!visibleSelection().isBaseFirst()) {
     return Range::create(*anchor.document(), shadowAdjustedNode(focus),
                          shadowAdjustedOffset(focus), node,
                          shadowAdjustedOffset(anchor));
   }
   return Range::create(*anchor.document(), node, shadowAdjustedOffset(anchor),
                        shadowAdjustedNode(focus), shadowAdjustedOffset(focus));
 }
 
 bool DOMSelection::isSelectionOfDocument() const {
@@ skipping 263 matching lines @@
     m_treeScope->document().addConsoleMessage(
         ConsoleMessage::create(JSMessageSource, ErrorMessageLevel, message));
 }
 
 DEFINE_TRACE(DOMSelection) {
   visitor->trace(m_treeScope);
   ContextClient::trace(visitor);
 }
 
 }  // namespace blink