Fix setComposingText when newCursorPosition != 1

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

 /*
  * Copyright (C) 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  *
  * 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 221 matching lines @@
     if (!selection.isNone() && !m_compositionRange->collapsed()) {
         if (selection.start().compareTo(m_compositionRange->startPosition()) >= 0
             && selection.end().compareTo(m_compositionRange->endPosition()) <= 0)
             return;
     }
 
     cancelComposition();
     frame().chromeClient().didCancelCompositionOnSelectionChange();
 }
 
-void InputMethodController::setComposition(const String& text, const Vector<CompositionUnderline>& underlines, unsigned selectionStart, unsigned selectionEnd)
+void InputMethodController::setComposition(const String& text, const Vector<CompositionUnderline>& underlines, int selectionStart, int selectionEnd)
 {
     Editor::RevealSelectionScope revealSelectionScope(&editor());
 
     // Updates styles before setting selection for composition to prevent
     // inserting the previous composition text into text nodes oddly.
     // See https://bugs.webkit.org/show_bug.cgi?id=46868
     frame().document()->updateLayoutTree();
 
     selectComposition();
 
@@ skipping 72 matching lines @@
     m_isDirty = true;
     m_hasComposition = true;
     if (!m_compositionRange)
         m_compositionRange = Range::create(baseNode->document());
     m_compositionRange->setStart(baseNode, baseOffset);
     m_compositionRange->setEnd(baseNode, extentOffset);
 
     if (baseNode->layoutObject())
         baseNode->layoutObject()->setShouldDoFullPaintInvalidation();
 
-    unsigned start = std::min(baseOffset + selectionStart, extentOffset);
-    unsigned end = std::min(std::max(start, baseOffset + selectionEnd), extentOffset);
-    Range* selectedRange = Range::create(baseNode->document(), baseNode, start, baseNode, end);
+    // In case of exceeding the left boundary.
+    int selectionOffsetsStart = static_cast<int>(getSelectionOffsets().start());
+    int start = std::max(selectionOffsetsStart + selectionStart, 0);
+    int end = std::max(selectionOffsetsStart + selectionEnd, start);
+
+    Element* rootEditableElement = frame().selection().rootEditableElement();
+    if (!rootEditableElement)
+        return;
+
+    // In case of exceeding the right boundary.
+    // If both |value1| and |value2| exceed right boundary,
+    // PlainTextRange(value1, value2)::createRange() will return a default
+    // value, which is [0,0]. In order to get the right boundary in that case,
+    // we should make sure |value1| is within range at least.
+    const EphemeralRange startRange = PlainTextRange(0, start).createRange(*rootEditableElement);

[aelias_OOO_until_Jul13, 2016/05/10 20:44:11]

These ranges are odd, wouldn't it have the same effect to just create two
Position objects instead?

[yabinh, 2016/05/11 00:28:38]

That's right. But in order to create Position objects, we need to know
|anchorNode| and |offset|. And PlainTextRange::createRange() can do that.

[aelias_OOO_until_Jul13, 2016/05/11 02:49:35]

OK, it looks like the algorithm in createRange() isn't split off anywhere else,
I guess it's OK then.  Please store Position objects as local variables instead
of the EphemeralRange to make it clearer that the ranges aren't really of
interest.

[yosin_UTC9, 2016/05/11 05:53:23]

nit: s/const EphemeralRange/const EphemeralRange&/ to avoid redundant copy

+    const EphemeralRange endRange = PlainTextRange(0, end).createRange(*rootEditableElement);

[yosin_UTC9, 2016/05/11 05:53:23]

nit: s/const EphemeralRange/const EphemeralRange&/ to avoid redundant copy

+
+    Range* selectedRange = Range::create(rootEditableElement->document(), startRange.endPosition(), endRange.endPosition());
     frame().selection().setSelectedRange(selectedRange, TextAffinity::Downstream, SelectionDirectionalMode::NonDirectional, NotUserTriggered);
 
     if (underlines.isEmpty()) {
         frame().document()->markers().addCompositionMarker(m_compositionRange->startPosition(), m_compositionRange->endPosition(), Color::black, false, LayoutTheme::theme().platformDefaultCompositionBackgroundColor());
         return;
     }
     for (const auto& underline : underlines) {
         unsigned underlineStart = baseOffset + underline.startOffset;
         unsigned underlineEnd = baseOffset + underline.endOffset;
         EphemeralRange ephemeralLineRange = EphemeralRange(Position(baseNode, underlineStart), Position(baseNode, underlineEnd));
@@ skipping 120 matching lines @@
     TypingCommand::deleteSelection(*frame().document());
 }
 
 DEFINE_TRACE(InputMethodController)
 {
     visitor->trace(m_frame);
     visitor->trace(m_compositionRange);
 }
 
 } // namespace blink