Introduce IsCaretAtEdgeOfInlineTextBox() to simplify ComputeInlineBoxPosition()

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

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple 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.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 737 matching lines @@
   return prev_box->BidiLevel() > inline_box->BidiLevel();
 }
 
 // TODO(yosin): We have a forward declaration here to reduce patch size. We'll
 // replice this with an implementation once review finished.
 static InlineBoxPosition AdjustInlineBoxPositionForTextDirection(InlineBox*,
                                                                  int,
                                                                  UnicodeBidi,
                                                                  TextDirection);
 
+// Returns true if |caret_offset| is at edge of |box| based on |affinity|.
+// |caret_offset| must be either |box.CaretMinOffset()| or
+// |box.CaretMaxOffset()|.
+static bool IsCaretAtEdgeOfInlineTextBox(int caret_offset,
+                                         const InlineTextBox& box,
+                                         TextAffinity affinity) {
+  if (caret_offset == box.CaretMinOffset())
+    return affinity == TextAffinity::kDownstream;
+  DCHECK_EQ(caret_offset, box.CaretMaxOffset());
+  if (affinity == TextAffinity::kUpstream)
+    return true;
+  return box.NextLeafChild() && box.NextLeafChild()->IsLineBreak();
+}
+
 template <typename Strategy>
 static InlineBoxPosition ComputeInlineBoxPositionTemplate(
     const PositionTemplate<Strategy>& position,
     TextAffinity affinity,
     TextDirection primary_direction) {
   InlineBox* inline_box = nullptr;
   int caret_offset = position.ComputeEditingOffset();
   Node* const anchor_node = position.AnchorNode();
   LayoutObject* layout_object =
       anchor_node->IsShadowRoot()
@@ skipping 42 matching lines @@
       int caret_min_offset = box->CaretMinOffset();
       int caret_max_offset = box->CaretMaxOffset();
 
       if (caret_offset < caret_min_offset || caret_offset > caret_max_offset ||
           (caret_offset == caret_max_offset && box->IsLineBreak()))
         continue;
 
       if (caret_offset > caret_min_offset && caret_offset < caret_max_offset)
         return InlineBoxPosition(box, caret_offset);
 
-      if (((caret_offset == caret_max_offset) ^
-           (affinity == TextAffinity::kDownstream)) ||
-          ((caret_offset == caret_min_offset) ^
-           (affinity == TextAffinity::kUpstream)) ||
-          (caret_offset == caret_max_offset && box->NextLeafChild() &&
-           box->NextLeafChild()->IsLineBreak())) {
+      if (IsCaretAtEdgeOfInlineTextBox(caret_offset, *box, affinity)) {
         inline_box = box;
         break;
       }
 
       candidate = box;
     }
     if (candidate && candidate == text_layout_object->LastTextBox() &&
         affinity == TextAffinity::kDownstream) {
       inline_box = SearchAheadForBetterMatch(text_layout_object);
       if (inline_box)
@@ skipping 1226 matching lines @@
 
 IntRect ComputeTextRect(const EphemeralRangeInFlatTree& range) {
   return EnclosingIntRect(ComputeTextRectTemplate(range));
 }
 
 FloatRect ComputeTextFloatRect(const EphemeralRange& range) {
   return ComputeTextRectTemplate(range);
 }
 
 }  // namespace blink