Refactor DocumentMarkerController

third_party/WebKit/Source/core/editing/markers/DocumentMarkerList.cpp

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/editing/markers/DocumentMarkerList.h"
+
+#include "core/editing/markers/DocumentMarkerController.h"
+
+namespace blink {
+
+DocumentMarkerList::DocumentMarkerList(
+    DocumentMarkerController* documentMarkerController)
+    : m_documentMarkerController(documentMarkerController) {}
+
+bool DocumentMarkerList::endsBefore(size_t startOffset,
+                                    const Member<DocumentMarker>& rhv) {
+  return startOffset < rhv->endOffset();
+}
+
+bool DocumentMarkerList::compareByStart(const Member<DocumentMarker>& lhv,
+                                        const Member<DocumentMarker>& rhv) {
+  return lhv->startOffset() < rhv->startOffset();
+}
+
+DocumentMarkerList::ShiftMarkerResult
+DocumentMarkerList::getShiftedMarkerPosition(const DocumentMarker& marker,
+                                             unsigned offset,
+                                             unsigned oldLength,
+                                             unsigned newLength) {
+  ShiftMarkerResult result;
+  result.newStartOffset = marker.startOffset();
+  result.newEndOffset = marker.endOffset();
+  result.shouldRemoveMarker = false;
+
+  // algorithm inspired by https://dom.spec.whatwg.org/#concept-cd-replace
+  // but with some changes
+  if (marker.startOffset() > offset) {
+    // Deviation from the concept-cd-replace algorithm: < instead of <= in
+    // the next line
+    if (marker.startOffset() < offset + oldLength) {
+      // Marker start was in the replaced text. Move to end of new text
+      // (Deviation from the concept-cd-replace algorithm: that algorithm
+      // would move to the beginning of the new text here)
+      result.newStartOffset = offset + newLength;
+    } else {
+      // Marker start was after the replaced text. Shift by length
+      // difference
+      result.newStartOffset = marker.startOffset() + newLength - oldLength;
+    }
+  }
+
+  if (marker.endOffset() > offset) {
+    // Deviation from the concept-cd-replace algorithm: < instead of <= in
+    // the next line
+    if (marker.endOffset() < offset + oldLength) {
+      // Marker end was in the replaced text. Move to beginning of new text
+      result.newEndOffset = offset;
+    } else {
+      // Marker end was after the replaced text. Shift by length difference
+      result.newEndOffset = marker.endOffset() + newLength - oldLength;
+    }
+  }
+
+  if (result.newStartOffset >= result.newEndOffset)
+    result.shouldRemoveMarker = true;
+
+  return result;
+}
+
+DEFINE_TRACE(DocumentMarkerList) {
+  visitor->trace(m_documentMarkerController);
+}
+
+}  // namespace blink