Custom model to keep track of database columns

In future commits I will be adding custom Dbo actions to be used
with Dbo's persist method to create a link between the custom
WFormModel and the database object. This base class will be used
by that custom WFormModel and those actions to keep track of
which database columns have been added to the model.

Author: YoikaG

src/Wt/Form/CMakeLists.txt

@@ -1,3 +1,5 @@
 FILE(GLOB FORM_H_FILES RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}" "*.h")
 INSTALL(FILES ${FORM_H_FILES}
         DESTINATION include/Wt/Form)
+
+ADD_SUBDIRECTORY(Dbo)

src/Wt/Form/Dbo/CMakeLists.txt

@@ -0,0 +1,3 @@
+FILE(GLOB FORM_DBO_H_FILES RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}" "*.h")
+INSTALL(FILES ${FORM_DBO_H_FILES}
+        DESTINATION include/Wt/Form/Dbo)

src/Wt/Form/Dbo/FormModelBase.h

@@ -0,0 +1,45 @@
+// This may look like C code, but it's really -*- C++ -*-
+/*
+ * Copyright (C) 2021 Emweb bv, Herent, Belgium.
+ *
+ * See the LICENSE file for terms of use.
+ */
+#ifndef WT_FORM_DBO_FORMMODELBASE_H_
+#define WT_FORM_DBO_FORMMODELBASE_H_
+
+#include <Wt/WFormModel.h>
+
+namespace Wt {
+  namespace Form {
+    namespace Dbo {
+/*! \brief A model class keeping information about database columns
+ * that are to be used in the model/view logic.
+ */
+class FormModelBase : public Wt::WFormModel
+{
+public:
+  FormModelBase()
+    : Wt::WFormModel()
+  {
+  }
+
+  /*! \brief Returns the Dbo columns used in this model
+   */
+  const std::vector<std::string>& dboFields() const { return dboFields_; }
+
+protected:
+  std::vector<std::string> dboFields_;
+
+  /*! \brief Adds a Dbo column as a field
+   */
+  void insertDboField(Wt::WFormModel::Field field)
+  {
+    dboFields_.push_back(field);
+    addField(field);
+  }
+};
+    }
+  }
+}
+
+#endif // WT_FORM_DBO_FORMMODELBASE