Clang: Move StringCacheEntry in extra file

Change-Id: I8ddd7194482ecf2d332e801d30aef5ed58ef4512
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/clangsupport/clangsupport-lib.pri

@@ -156,6 +156,7 @@ HEADERS += \
     $$PWD/refactoringserverproxy.h \
     $$PWD/referencesmessage.h \
     $$PWD/set_algorithm.h \
+    $$PWD/stringcacheentry.h \
     $$PWD/unsavedfilesupdatedmessage.h \
     $$PWD/removeprojectpartsmessage.h \
     $$PWD/requestannotationsmessage.h \

src/libs/clangsupport/filepathstoragesources.h

@@ -25,6 +25,8 @@
 
 #pragma once
 
+#include "stringcacheentry.h"
+
 #include <utils/smallstring.h>
 
 #include <cstdint>
@@ -34,22 +36,6 @@
 
 namespace ClangBackEnd {
 
-template<typename StringType, typename StringViewType, typename IndexType>
-class StringCacheEntry
-{
-public:
-    StringCacheEntry(StringViewType string, IndexType id)
-        : string(string)
-        , id(id)
-    {}
-
-    operator StringViewType() const { return string; }
-
-public:
-    StringType string;
-    IndexType id;
-};
-
 class FileNameView
 {
 public:

src/libs/clangsupport/stringcacheentry.h

@@ -0,0 +1,50 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#pragma once
+
+namespace ClangBackEnd {
+
+template<typename StringType, typename StringViewType, typename IndexType>
+class StringCacheEntry
+{
+public:
+    StringCacheEntry(StringViewType string, IndexType id)
+        : string(string)
+        , id(id)
+    {}
+
+    operator StringViewType() const { return string; }
+    friend bool operator==(const StringCacheEntry &first, const StringCacheEntry &second)
+    {
+        return first.id == second.id && first.string == second.string;
+    }
+
+public:
+    StringType string;
+    IndexType id;
+};
+
+} // namespace ClangBackEnd