Fix InputConnection.deleteSurroundingText()

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 471 matching lines @@
             return;
         if (before == 0)
             break;
         ++before;
     } while (frame().selection().start() == frame().selection().end() && before <= static_cast<int>(selectionOffsets.start()));
     // TODO(chongz): According to spec |data| should be "forward" or "backward".
     dispatchBeforeInputEditorCommand(frame().document()->focusedElement(), InputEvent::InputType::DeleteContent);
     TypingCommand::deleteSelection(*frame().document());
 }
 
+void InputMethodController::deleteSurroundingText(size_t before, size_t after)
+{
+    if (!editor().canEdit())
+        return;
+    PlainTextRange selectionOffsets(getSelectionOffsets());
+    if (selectionOffsets.isNull())
+        return;
+    size_t selectionStart = selectionOffsets.start();
+    size_t selectionEnd = selectionOffsets.end();
+    Element* rootEditableElement = frame().selection().rootEditableElement();
+    if (!rootEditableElement)
+        return;
+
+    bool deleteBeforeText = before > 0u && selectionStart > 0u;
+    bool deleteAftertext = after > 0u;
+
+    if (deleteBeforeText) {
+        // In case of exceeding the left boundary.
+        int deletionStart = selectionStart - std::min(selectionStart, before);
+
+        // Delete the text before selectionStart.
+        // For multi-code text, we can't delete it successfully if we only
+        // delete the right half of it. So we need to adjust the start of
+        // deletion.
+        const EphemeralRange& startRange = PlainTextRange(0, deletionStart).createRange(*rootEditableElement);
+        const Position& startPosition = startRange.endPosition();
+        Node* anchorNode = startPosition.anchorNode();
+        int deletionStartInContainerNode = startPosition.computeOffsetInContainerNode();
+
+        const Position position(anchorNode, deletionStartInContainerNode + 1);
+        const Position& adjustedPosition = previousPositionOf(position, PositionMoveType::GraphemeCluster);
+        int adjustedDeletionStart = adjustedPosition.computeOffsetInContainerNode();
+
+        Range* deletedRange = Range::create(*frame().document(), adjustedPosition, frame().selection().start());
+        deletedRange->deleteContents(ASSERT_NO_EXCEPTION);
+
+        size_t deletedLength = selectionStart - static_cast<size_t>(deletionStart + deletionStartInContainerNode - adjustedDeletionStart);
+        selectionEnd = selectionEnd - deletedLength;
+    }
+
+    if (deleteAftertext) {
+        // In case of exceeding the right boundary.
+        PlainTextRange range(static_cast<int>(selectionEnd), static_cast<int>(selectionEnd + after));
+        if (range.isNull())
+            return;
+        const EphemeralRange adjustedRange = range.createRange(*rootEditableElement);
+        if (adjustedRange.isNull())
+            return;
+
+        const Position& endPosition = adjustedRange.endPosition();
+        Node* anchorNode = endPosition.anchorNode();
+        int deletionEndInContainerNode = endPosition.computeOffsetInContainerNode();
+
+        // Delete the text after selectionEnd.
+        // We also need to adjust the end of deletion for multi-code text.
+        Position position(anchorNode, deletionEndInContainerNode - 1);
+        Position adjustedPosition = nextPositionOf(position, PositionMoveType::GraphemeCluster);
+
+        Range* deletedRange = Range::create(*frame().document(), frame().selection().end(), adjustedPosition);
+        deletedRange->deleteContents(ASSERT_NO_EXCEPTION);
+    }
+
+    if (deleteBeforeText  || deleteAftertext) {
+        rootEditableElement->dispatchEvent(Event::create(EventTypeNames::webkitEditableContentChanged));
+    }
+
+    if (deleteBeforeText) {
+        rootEditableElement->dispatchEvent(Event::create(EventTypeNames::selectionchange));
+    }
+}
+
 DEFINE_TRACE(InputMethodController)
 {
     visitor->trace(m_frame);
     visitor->trace(m_compositionRange);
 }
 
 } // namespace blink