Sqlite: Add variadic bind and write functions

You can now write

SqliteWriteStatement statement("UPDATE test SET name=?, number=?
                                WHERE rowid=?", database);

statement.write("see", 7.23, 1);

and

SqliteWriteStatement statement("UPDATE test SET name=@name, number=@number
                                WHERE rowid=@id", database);

statement.writeNamed("@name", "see", "@number", 7.23, "@id", 1);

This is more type safe than using variants and performant too.

Change-Id: Ie1ed2a6d326b956be5c4ec056214f3f5b1531f45
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/sqlite/sqlitedatabasebackend.h

@@ -33,13 +33,17 @@ struct sqlite3;
 
 namespace Sqlite {
 
+class SqliteDatabase;
+
 class SQLITE_EXPORT SqliteDatabaseBackend
 {
 public:
-
-    SqliteDatabaseBackend();
+    SqliteDatabaseBackend(SqliteDatabase &database);
     ~SqliteDatabaseBackend();
 
+    SqliteDatabaseBackend(const SqliteDatabase &database) = delete;
+    SqliteDatabase &operator=(const SqliteDatabase &database) = delete;
+
     void setMmapSize(qint64 defaultSize, qint64 maximumSize);
     void activateMultiThreading();
     void activateLogging();
@@ -59,8 +63,6 @@ public:
     void setTextEncoding(TextEncoding textEncoding);
     TextEncoding textEncoding();
 
-
-
     Utils::SmallStringVector columnNames(Utils::SmallStringView tableName);
 
     int changesCount();
@@ -105,6 +107,7 @@ protected:
     Q_NORETURN void throwException(const char *whatHasHappens) const;
 
 private:
+    SqliteDatabase &m_database;
     sqlite3 *m_databaseHandle;
     TextEncoding m_cachedTextEncoding;