Introduce Selection class

third_party/WebKit/Source/core/editing/SelectionTemplate.h

+// Copyright 2016 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.
+
+#ifndef SelectionTemplate_h
+#define SelectionTemplate_h
+
+#include "base/macros.h"
+#include "core/CoreExport.h"
+#include "core/editing/EphemeralRange.h"
+#include "core/editing/Position.h"
+#include "core/editing/PositionWithAffinity.h"
+#include "core/editing/TextAffinity.h"
+#include "core/editing/TextGranularity.h"
+#include "wtf/Allocator.h"
+#include <iosfwd>
+
+namespace blink {
+
+// SelectionTemplate is used for representing a selection in DOM tree or Flat
+// tree with template parameter |Strategy|. Instances of |SelectionTemplate|
+// are immutable objects, you can't change them once constructed.
+//
+// To construct |SelectionTemplate| object, please use |Builder| class.
+template <typename Strategy>
+class CORE_EXPORT SelectionTemplate final {
+  DISALLOW_NEW();
+
+ public:
+  // |Builder| is a helper class for constructing |SelectionTemplate| object.
+  class CORE_EXPORT Builder final {
+    DISALLOW_NEW();
+
+   public:
+    explicit Builder(const SelectionTemplate&);
+    Builder();
+
+    SelectionTemplate build() const;
+
+    // Move selection to |base|. |base| can't be null.
+    Builder& collapse(const PositionTemplate<Strategy>& base);
+    Builder& collapse(const PositionWithAffinityTemplate<Strategy>& base);
+
+    // Extend selection to |extent|. It is error if selection is none.
+    // |extent| can be in different tree scope of base, but should be in same
+    // document.
+    Builder& extend(const PositionTemplate<Strategy>& extent);
+
+    Builder& setBaseAndExtent(const EphemeralRangeTemplate<Strategy>&);
+
+    // |extent| can not be null if |base| isn't null.
+    Builder& setBaseAndExtent(const PositionTemplate<Strategy>& base,
+                              const PositionTemplate<Strategy>& extent);
+
+    // |extent| can be non-null while |base| is null, which is undesired.
+    // Note: This function should be used only in "core/editing/commands".
+    // TODO(yosin): Once all we get rid of all call sites, we remove this.
+    Builder& setBaseAndExtentDeprecated(
+        const PositionTemplate<Strategy>& base,
+        const PositionTemplate<Strategy>& extent);
+
+    Builder& setAffinity(TextAffinity);
+    Builder& setGranularity(TextGranularity);
+    Builder& setHasTrailingWhitespace(bool);
+    Builder& setIsDirectional(bool);
+
+   private:
+    SelectionTemplate m_selection;
+
+    DISALLOW_COPY_AND_ASSIGN(Builder);
+  };
+
+  SelectionTemplate(const SelectionTemplate& other);
+  SelectionTemplate();
+
+  SelectionTemplate& operator=(const SelectionTemplate&) = default;
+
+  bool operator==(const SelectionTemplate&) const;
+  bool operator!=(const SelectionTemplate&) const;
+
+  const PositionTemplate<Strategy>& base() const;
+  const PositionTemplate<Strategy>& extent() const;
+  TextAffinity affinity() const { return m_affinity; }
+  TextGranularity granularity() const { return m_granularity; }
+  bool hasTrailingWhitespace() const { return m_hasTrailingWhitespace; }
+  bool isDirectional() const { return m_isDirectional; }
+  bool isNone() const { return m_base.isNull(); }
+
+  // Returns true if |this| selection holds valid values otherwise it causes
+  // assertion failure.
+  bool assertValid() const;
+  bool assertValidFor(const Document&) const;
+
+  DEFINE_INLINE_TRACE() {
+    visitor->trace(m_base);
+    visitor->trace(m_extent);
+  }
+
+  void printTo(std::ostream*, const char* type) const;
+
+ private:
+  friend class SelectionEditor;
+
+  Document* document() const;
+
+  PositionTemplate<Strategy> m_base;
+  PositionTemplate<Strategy> m_extent;
+  TextAffinity m_affinity = TextAffinity::Downstream;
+  TextGranularity m_granularity = CharacterGranularity;
+  bool m_hasTrailingWhitespace = false;
+  bool m_isDirectional = false;
+#if DCHECK_IS_ON()
+  uint64_t m_domTreeVersion;
+#endif
+};
+
+extern template class CORE_EXTERN_TEMPLATE_EXPORT
+    SelectionTemplate<EditingStrategy>;
+extern template class CORE_EXTERN_TEMPLATE_EXPORT
+    SelectionTemplate<EditingInFlatTreeStrategy>;
+
+using SelectionInDOMTree = SelectionTemplate<EditingStrategy>;
+using SelectionInFlatTree = SelectionTemplate<EditingInFlatTreeStrategy>;
+
+CORE_EXPORT std::ostream& operator<<(std::ostream&, const SelectionInDOMTree&);
+CORE_EXPORT std::ostream& operator<<(std::ostream&, const SelectionInFlatTree&);
+
+}  // namespace blink
+
+#endif  // SelectionTemplate_h