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 530 matching lines @@
         if (before == 0)
             break;
         ++before;
     } while (frame().selection().start() == frame().selection().end() && before <= static_cast<int>(selectionOffsets.start()));
     // TODO(chongz): New spec might want to change InputType.
     // https://github.com/w3c/editing/issues/125#issuecomment-213041256
     dispatchBeforeInputEditorCommand(m_frame->document()->focusedElement(), InputEvent::InputType::DeleteContent, emptyString(), new RangeVector(1, m_frame->selection().firstRange()));
     TypingCommand::deleteSelection(*frame().document());
 }
 
+// TODO(yabinh): We should reduce the number of selectionchange events.
+void InputMethodController::deleteSurroundingText(size_t before, size_t after)
+{
+    if (!editor().canEdit())
+        return;
+    PlainTextRange selectionOffsets(getSelectionOffsets());
+    if (selectionOffsets.isNull())
+        return;
+    Element* rootEditableElement = frame().selection().rootEditableElement();
+    if (!rootEditableElement)
+        return;
+
+    size_t selectionStart = selectionOffsets.start();
+    size_t selectionEnd = selectionOffsets.end();
+
+    if (before > 0u && selectionStart > 0u) {
+        // In case of exceeding the left boundary.
+        int start = std::max(static_cast<int>(selectionStart) - static_cast<int>(before), 0);
+
+        if (rootEditableElement->innerText()[start] != '\n') {
+            // Select the text to be deleted before selectionStart.
+            // For multi-code text, we can't select it successfully if we only
+            // select the right half of it. So we need to adjust the start of
+            // selection.
+            const EphemeralRange range = PlainTextRange(start, start + 1).createRange(*rootEditableElement);
+            if (range.isNull())
+                return;
+
+            Position position = range.startPosition();
+            Position nextPosition = range.endPosition();
+            Position adjustedPosition = previousPositionOf(nextPosition, PositionMoveType::GraphemeCluster);
+
+            int diff = adjustedPosition.computeOffsetInContainerNode() - position.computeOffsetInContainerNode();
+            start = start + diff;
+        }
+
+        if (!setSelectionOffsets(PlainTextRange(start, static_cast<int>(selectionStart))))
+            return;
+        TypingCommand::deleteSelection(*frame().document());
+
+        selectionEnd = selectionEnd - (selectionStart - start);
+        selectionStart = start;
+    }
+
+    if (after > 0u) {
+        // Adjust the deleted range in case of exceeding the right boundary.
+        PlainTextRange deletionRange(static_cast<int>(selectionEnd), static_cast<int>(selectionEnd + after));
+        if (deletionRange.isNull())
+            return;
+        const EphemeralRange validRange = deletionRange.createRange(*rootEditableElement);
+        if (validRange.isNull())
+            return;
+        PlainTextRange validDeletionRange = PlainTextRange::create(*rootEditableElement, validRange);
+        if (validDeletionRange.isNull())
+            return;
+        int end = validDeletionRange.end();
+
+        if (rootEditableElement->innerText()[end - 1] != '\n') {
+            // We also need to adjust the end of selection for multi-code text.
+            const EphemeralRange range = PlainTextRange(end - 1, end).createRange(*rootEditableElement);
+            if (range.isNull())
+                return;
+
+            Position position = range.endPosition();
+            Position previousPosition = range.startPosition();
+            Position adjustedPosition = nextPositionOf(previousPosition, PositionMoveType::GraphemeCluster);
+
+            int diff = adjustedPosition.computeOffsetInContainerNode() - position.computeOffsetInContainerNode();
+            end = end + diff;
+        }
+
+        if (!setSelectionOffsets(PlainTextRange(static_cast<int>(selectionEnd), end)))
+            return;
+        TypingCommand::deleteSelection(*frame().document());
+    }
+
+    setSelectionOffsets(PlainTextRange(selectionStart, selectionEnd));
+}
+
 DEFINE_TRACE(InputMethodController)
 {
     visitor->trace(m_frame);
     visitor->trace(m_compositionRange);
 }
 
 } // namespace blink