Reland: Fix setComposingText with empty text 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 303 matching lines @@
 
     selectComposition();
 
     if (frame().selection().isNone())
         return;
 
     Element* target = frame().document()->focusedElement();
     if (!target)
         return;
 
+    int selectionOffsetsStart = static_cast<int>(getSelectionOffsets().start());
+    int start = selectionOffsetsStart + selectionStart;
+    int end = selectionOffsetsStart + selectionEnd;
+

[yosin_UTC9, 2016/06/15 05:34:41]

Could you add DCHECK_XX() to validate |start| and |end| have valid values?

[yosin_UTC9, 2016/06/15 19:00:21]

I mean

DCHECK_GE(selctionStart, 0);
DCHECK_LE(selectionStart, selectionEnd);

     // Dispatch an appropriate composition event to the focused node.
     // We check the composition status and choose an appropriate composition event since this
     // function is used for three purposes:
     // 1. Starting a new composition.
     //    Send a compositionstart and a compositionupdate event when this function creates
     //    a new composition node, i.e.
     //    !hasComposition() && !text.isEmpty().
     //    Sending a compositionupdate event at this time ensures that at least one
     //    compositionupdate event is dispatched.
     // 2. Updating the existing composition node.
     //    Send a compositionupdate event when this function updates the existing composition
     //    node, i.e. hasComposition() && !text.isEmpty().
     // 3. Canceling the ongoing composition.
     //    Send a compositionend event when function deletes the existing composition node, i.e.
     //    !hasComposition() && test.isEmpty().
     if (text.isEmpty()) {
         if (hasComposition()) {
             confirmComposition(emptyString());
-            return;
+        } else {
+            // It's weird to call |setComposition()| with empty text outside composition, however some IME
+            // (e.g. Japanese IBus-Anthy) did this, so we simply delete selection without sending extra events.
+            TypingCommand::deleteSelection(*frame().document(), TypingCommand::PreventSpellChecking);
         }
-        // It's weird to call |setComposition()| with empty text outside composition, however some IME
-        // (e.g. Japanese IBus-Anthy) did this, so we simply delete selection without sending extra events.
-        TypingCommand::deleteSelection(*frame().document(), TypingCommand::PreventSpellChecking);
+
+        setEditableSelectionOffsets(PlainTextRange(start, end));
         return;
     }
 
     // We should send a 'compositionstart' event only when the given text is not empty because this
     // function doesn't create a composition node when the text is empty.
     if (!hasComposition()) {
         target->dispatchEvent(CompositionEvent::create(EventTypeNames::compositionstart, frame().domWindow(), frame().selectedText()));
         if (!frame().document())
             return;
     }
@@ skipping 26 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();
 
-    // 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 correct Position in that case,
-    // we should make sure |value1| is within range at least.
-    const EphemeralRange& startRange = PlainTextRange(0, start).createRange(*rootEditableElement);
-    const EphemeralRange& endRange = PlainTextRange(0, end).createRange(*rootEditableElement);
-
-    // TODO(yabinh): There should be a better way to create |startPosition| and
-    // |endPosition|. But for now, since we can't get |anchorNode| and |offset|,
-    // we can't create the 2 Position objects directly. So we use
-    // PlainTextRange::createRange as a workaround.
-    const Position& startPosition = startRange.endPosition();
-    const Position& endPosition = endRange.endPosition();
-    const EphemeralRange selectedRange(startPosition, endPosition);
+    const EphemeralRange selectedRange = PlainTextRange(start, end).createRange(*rootEditableElement);

[yosin_UTC9, 2016/06/15 05:34:41]

s/const EphemeralRange/const EphmeralRange&/
to avoid copy.

     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 121 matching lines @@
     TypingCommand::deleteSelection(*frame().document());
 }
 
 DEFINE_TRACE(InputMethodController)
 {
     visitor->trace(m_frame);
     visitor->trace(m_compositionRange);
 }
 
 } // namespace blink