Introduce TextBuffer as Output Type of copyTextTo() for Text Iterators

third_party/WebKit/Source/core/editing/iterators/TextBuffer.h

Index: third_party/WebKit/Source/core/editing/iterators/TextBuffer.h
diff --git a/third_party/WebKit/Source/core/editing/iterators/TextBuffer.h b/third_party/WebKit/Source/core/editing/iterators/TextBuffer.h
new file mode 100644
index 0000000000000000000000000000000000000000..5e81ea2de85172d1bac32c7a05291b03f8fccd64
--- /dev/null
+++ b/third_party/WebKit/Source/core/editing/iterators/TextBuffer.h
@@ -0,0 +1,72 @@
+// 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 TextBuffer_h
+#define TextBuffer_h
+
+#include "core/CoreExport.h"
+#include "wtf/text/WTFString.h"

[yosin_UTC9, 2016/01/28 09:06:17]

nit: #include "wtf/Vector.h"

+
+namespace blink {
+
+class CORE_EXPORT TextBufferBase {
+    STACK_ALLOCATED();

[yosin_UTC9, 2016/01/28 09:06:17]

 WTF_MAKE_NONCOPYABLE(TextBufferBase) see wtf/Noncopyable.h

+public:
+    TextBufferBase();

[yosin_UTC9, 2016/01/28 09:06:17]

nit: |TextBufferBase()| ctor should be protected.

+
+    void clear() { m_size = 0; }
+    size_t size() const { return m_size; }
+    bool isEmpty() const { return m_size == 0; }
+    const UChar& operator[](size_t index) const { ASSERT(index < m_size); return data()[index]; }
+    virtual const UChar* data() const = 0;
+
+    void pushCharacters(UChar, size_t length);
+
+    template<typename T>
+    void pushRange(const T* other, size_t length)
+    {
+        if (length == 0)
+            return;
+        std::copy(other, other + length, pushInternal(length));
+    }
+
+protected:
+    UChar* pushInternal(size_t length);
+    void grow(size_t demand);
+
+    virtual UChar* pushDestination(size_t length) = 0;
+    virtual void shiftData(size_t oldCapacity) {}

[yosin_UTC9, 2016/01/28 09:06:17]

nit: Don't inline virtual function.

+
+    size_t m_size = 0;
+    Vector<UChar, 1024> m_buffer;
+};
+
+class CORE_EXPORT ForwardsTextBuffer final : public TextBufferBase {
+    STACK_ALLOCATED();

[yosin_UTC9, 2016/01/28 09:06:17]

 WTF_MAKE_NONCOPYABLE(ForwardsTextBuffer) see wtf/Noncopyable.h

+public:
+    const UChar* data() const override;
+
+private:
+    using TextBufferBase::m_size;

[yosin_UTC9, 2016/01/28 09:06:17]

nit: We should use protected member function instead of accessing member
variable in base class.

+    using TextBufferBase::m_buffer;
+
+    UChar* pushDestination(size_t length) override;
+};
+
+class CORE_EXPORT BackwardsTextBuffer final : public TextBufferBase {
+    STACK_ALLOCATED();

[yosin_UTC9, 2016/01/28 09:06:17]

 WTF_MAKE_NONCOPYABLE(BackwardsTextBuffer) see wtf/Noncopyable.h

+public:
+    const UChar* data() const override;
+
+private:
+    using TextBufferBase::m_size;
+    using TextBufferBase::m_buffer;
+
+    UChar* pushDestination(size_t length) override;
+    void shiftData(size_t oldCapacity) override;
+};
+
+} // namespace blink
+
+#endif // TextBuffer_h