Refactor CanBe{Back,For}wardCaretPosition()

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 2018 matching lines @@
 
       if (CanBeBackwardCaretPosition(text_layout_object,
                                      current_pos.OffsetInLeafNode())) {
         return current_pos.ComputePosition();
       }
     }
   }
   return last_visible.DeprecatedComputePosition();
 }
 
+// The text continues on the next line only if the last text box is not on this
+// line and none of the boxes on this line have a larger start offset.
+static bool DoesContinueOnNextLine(const LayoutText& text_layout_object,
+                                   InlineBox* box,
+                                   unsigned text_offset) {
+  InlineTextBox* const last_text_box = text_layout_object.LastTextBox();
+  DCHECK_NE(box, last_text_box);
+  for (InlineBox* runner = box->NextLeafChild(); runner;
+       runner = runner->NextLeafChild()) {
+    if (runner == last_text_box)
+      return false;
+    if (LineLayoutAPIShim::LayoutObjectFrom(runner->GetLineLayoutItem()) ==
+            text_layout_object &&
+        ToInlineTextBox(runner)->Start() >= text_offset)
+      return false;
+  }
+
+  for (InlineBox* runner = box->PrevLeafChild(); runner;
+       runner = runner->PrevLeafChild()) {
+    if (runner == last_text_box)
+      return false;
+    if (LineLayoutAPIShim::LayoutObjectFrom(runner->GetLineLayoutItem()) ==
+            text_layout_object &&
+        ToInlineTextBox(runner)->Start() >= text_offset)
+      return false;
+  }
+
+  return true;
+}
+
 // TODO(editing-dev): This function is just moved out from
 // |MostBackwardCaretPosition()|. We should study this function more and
 // name it appropriately. See https://trac.webkit.org/changeset/32438/
 // which introduce this.
 static bool CanBeBackwardCaretPosition(const LayoutText* text_layout_object,
                                        int offset_in_node) {
   const unsigned text_start_offset = text_layout_object->TextStartOffset();
   DCHECK_GE(offset_in_node, static_cast<int>(text_start_offset));
   const unsigned text_offset = offset_in_node - text_start_offset;
   InlineTextBox* const last_text_box = text_layout_object->LastTextBox();
@@ skipping 19 matching lines @@
     }
     if (text_offset <= box->Start() + box->Len()) {
       if (text_offset > box->Start())
         return true;
       continue;
     }
 
     if (box == last_text_box || text_offset != box->Start() + box->Len() + 1)
       continue;
 
-    // TODO(yosin): We should move below code fragment into
-    // |DoesContinueOnNextLine()|. Note: |MostForwardCaretPosition()| has
-    // same code fragment except for comparison on |text_offset|.
-    // Backward: other_box->Start() >  text_offset
-    // Forward:  other_box->Start() >= text_offset
-    // The text continues on the next line only if the last text box is not
-    // on this line and none of the boxes on this line have a larger start
-    // offset.
-    bool continues_on_next_line = true;
-    InlineBox* other_box = box;
-    while (continues_on_next_line) {
-      other_box = other_box->NextLeafChild();
-      if (!other_box)
-        break;
-      if (other_box == last_text_box ||
-          (LineLayoutAPIShim::LayoutObjectFrom(
-               other_box->GetLineLayoutItem()) == text_layout_object &&
-           ToInlineTextBox(other_box)->Start() > text_offset))
-        continues_on_next_line = false;
-    }
-
-    other_box = box;
-    while (continues_on_next_line) {
-      other_box = other_box->PrevLeafChild();
-      if (!other_box)
-        break;
-      if (other_box == last_text_box ||
-          (LineLayoutAPIShim::LayoutObjectFrom(
-               other_box->GetLineLayoutItem()) == text_layout_object &&
-           ToInlineTextBox(other_box)->Start() > text_offset))
-        continues_on_next_line = false;
-    }
-
-    if (continues_on_next_line)
+    if (DoesContinueOnNextLine(*text_layout_object, box, text_offset + 1))
       return true;
   }
   return false;
 }
 
 Position MostBackwardCaretPosition(const Position& position,
                                    EditingBoundaryCrossingRule rule) {
   return MostBackwardCaretPosition<EditingStrategy>(position, rule);
 }
 
@@ skipping 118 matching lines @@
        box = box->NextTextBox()) {
     if (text_offset <= box->end()) {
       if (text_offset >= box->Start())
         return true;
       continue;
     }
 
     if (box == last_text_box || text_offset != box->Start() + box->Len())
       continue;
 
-    // TODO(yosin): We should move below code fragment into
-    // |DoesContinueOnNextLine()|. Note: |MostBackwardCaretPosition()| has
-    // same code fragment except for comparison on |text_offset|.
-    // Backward: other_box->Start() >  text_offset
-    // Forward:  other_box->Start() >= text_offset
-    // The text continues on the next line only if the last text box is not
-    // on this line and none of the boxes on this line have a larger start
-    // offset.
-    bool continues_on_next_line = true;
-    InlineBox* other_box = box;
-    while (continues_on_next_line) {
-      other_box = other_box->NextLeafChild();
-      if (!other_box)
-        break;
-      if (other_box == last_text_box ||
-          (LineLayoutAPIShim::LayoutObjectFrom(
-               other_box->GetLineLayoutItem()) == text_layout_object &&
-           ToInlineTextBox(other_box)->Start() >= text_offset))
-        continues_on_next_line = false;
-    }
-
-    other_box = box;
-    while (continues_on_next_line) {
-      other_box = other_box->PrevLeafChild();
-      if (!other_box)
-        break;
-      if (other_box == last_text_box ||
-          (LineLayoutAPIShim::LayoutObjectFrom(
-               other_box->GetLineLayoutItem()) == text_layout_object &&
-           ToInlineTextBox(other_box)->Start() >= text_offset))
-        continues_on_next_line = false;
-    }
-
-    if (continues_on_next_line)
+    if (DoesContinueOnNextLine(*text_layout_object, box, text_offset))
       return true;
   }
   return false;
 }
 
 Position MostForwardCaretPosition(const Position& position,
                                   EditingBoundaryCrossingRule rule) {
   return MostForwardCaretPosition<EditingStrategy>(position, rule);
 }
 
@@ skipping 871 matching lines @@
 
 IntRect ComputeTextRect(const EphemeralRangeInFlatTree& range) {
   return EnclosingIntRect(ComputeTextRectTemplate(range));
 }
 
 FloatRect ComputeTextFloatRect(const EphemeralRange& range) {
   return ComputeTextRectTemplate(range);
 }
 
 }  // namespace blink