Fix setComposingText when newCursorPosition != 1

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

Index: third_party/WebKit/Source/core/editing/InputMethodController.cpp
diff --git a/third_party/WebKit/Source/core/editing/InputMethodController.cpp b/third_party/WebKit/Source/core/editing/InputMethodController.cpp
index 0d88e0f740a014a088b732b6340f8ca8bef0e15e..29568e1d15b4f94b1169e46d0417ee8468ff39ff 100644
--- a/third_party/WebKit/Source/core/editing/InputMethodController.cpp
+++ b/third_party/WebKit/Source/core/editing/InputMethodController.cpp
@@ -239,7 +239,7 @@ void InputMethodController::cancelCompositionIfSelectionIsInvalid()
     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());
 
@@ -332,8 +332,16 @@ void InputMethodController::setComposition(const String& text, const Vector<Comp
     if (baseNode->layoutObject())
         baseNode->layoutObject()->setShouldDoFullPaintInvalidation();
 
-    unsigned start = std::min(baseOffset + selectionStart, extentOffset);
-    unsigned end = std::min(std::max(start, baseOffset + selectionEnd), extentOffset);
+    // In case of exceeding the left boundary.
+    int start = std::max(static_cast<int>(baseOffset) + selectionStart, 0);
+    int end = std::max(static_cast<int>(baseOffset) + selectionEnd, start);
+
+    // In case of exceeding the right boundary.
+    const EphemeralRange textRange = PlainTextRange(0, end).createRange(*(baseNode->parentElement()));
+    int textEnd = textRange.endPosition().computeOffsetInContainerNode();

[Changwan Ryu, 2016/05/02 06:49:00]

How about simply the following?

int textEnd = Position::lastOffsetForEditing(baseNode);

[yabinh, 2016/05/02 09:48:10]

Do you mean:
int textEnd = EditingStrategy::lastOffsetForEditing(baseNode);

It can't work correctly for multiple nodes, because textEnd is the length of
text in the current node, not the length of the whole text.

[Changwan Ryu, 2016/05/02 10:51:49]

Ok, I couldn't find a better solution here. But calling parentElement() doesn't
seem right.
Could you add the following test cases?
1) baseNode is two levels below the contenteditable, such that
baseNode->parentElement() can fail.
2) Adding selectionStart ends up in a node other than the currently
selected/composited node (such that lastOffsetForEditing() can fail)

+    start = std::min(start, textEnd);
+    end = std::min(end, textEnd);
+
     Range* selectedRange = Range::create(baseNode->document(), baseNode, start, baseNode, end);
     frame().selection().setSelectedRange(selectedRange, TextAffinity::Downstream, SelectionDirectionalMode::NonDirectional, NotUserTriggered);