WIP: Introduce CompressibleString

third_party/WebKit/Source/wtf/text/CompressableString.h

+// Copyright 2015 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 CompressableString_h
+#define CompressableString_h
+
+#include "wtf/text/Unicode.h"
+#include "wtf/text/WTFString.h"
+
+namespace WTF {
+
+class WTF_EXPORT CompressableString : public RefCounted<CompressableString> {
+public:
+    static PassRefPtr<CompressableString> create(const String&);
+
+    unsigned length() const;
+    bool isEmpty() const;
+    bool isCompressed() const { return m_isCompressed; }
+    bool is8Bit() const;
+    void compress();

[esprehn, 2015/10/24 03:59:26]

Why is compress() public? Why would a caller ever want to explicitly compress
instead of having the string decide.

[hajimehoshi, 2015/10/26 09:34:03]

Done.

+
+    String toString();
+
+private:
+    CompressableString();
+    explicit CompressableString(const String&);
+
+    void uncompress();
+
+    bool m_isCompressed;

[haraken, 2015/10/22 16:03:31]

Move this boolean to below m_is8Bit (to save sizeof(CompressableString)).

[esprehn, 2015/10/24 03:59:26]

You need to also combine them with a bitfield for windows.

[hajimehoshi, 2015/10/26 09:34:03]

Done.

+    RefPtr<StringImpl> m_impl;
+    const unsigned m_originalLength;
+    const bool m_is8Bit;
+};
+
+} // namespace WTF
+
+using WTF::CompressableString;
+
+#endif