ClangRefactoring: Initialize sqlite database only once

Initializing the database is not cheap so it is better to initializing it
only once. We simply check if the database file already exists and then
skip the initializing step.

Task-number: QTCREATORBUG-21174
Change-Id: I151090c5081c009f7913a30517065be2833791d8
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

src/libs/sqlite/sqlitedatabase.h

@@ -56,7 +56,7 @@ public:
 
     Database();
     Database(Utils::PathString &&databaseFilePath,
-             JournalMode journalMode=JournalMode::Wal);
+             JournalMode journalMode);
     Database(Utils::PathString &&databaseFilePath,
              std::chrono::milliseconds busyTimeout = 1000ms,
              JournalMode journalMode=JournalMode::Wal);
@@ -69,6 +69,9 @@ public:
     void open(Utils::PathString &&databaseFilePath);
     void close();
 
+    bool isInitialized() const;
+    void setIsInitialized(bool isInitialized);
+
     bool isOpen() const;
 
     Table &addTable();
@@ -133,6 +136,7 @@ private:
     JournalMode m_journalMode = JournalMode::Wal;
     OpenMode m_openMode = OpenMode::ReadWrite;
     bool m_isOpen = false;
+    bool m_isInitialized = false;
 };
 
 } // namespace Sqlite