filter: add filter preset undo commands

Add undo commands to add / edit / delete filter presets.
These are styled after the other undo commands: On changes,
the UI is informed by DiveListNotifier signals. Editing is
a simple std::swap of values.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

commands/command_filter.cpp

@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "command_filter.h"
+#include "core/filterpreset.h"
+#include "core/subsurface-qt/divelistnotifier.h"
+
+namespace Command {
+
+static int createFilterPreset(const QString &name, const FilterData &data)
+{
+	int index = filter_preset_add(name, data);
+	emit diveListNotifier.filterPresetAdded(index);
+	return index;
+}
+
+static std::pair<QString, FilterData> removeFilterPreset(int index)
+{
+	QString oldName = filter_preset_name_qstring(index);
+	FilterData oldData = filter_preset_get(index);
+	filter_preset_delete(index);
+	emit diveListNotifier.filterPresetRemoved(index);
+	return { oldName, oldData };
+}
+
+CreateFilterPreset::CreateFilterPreset(const QString &nameIn, const FilterData &dataIn) :
+	name(nameIn), data(dataIn), index(0)
+{
+	setText(Command::Base::tr("Create filter preset %1").arg(nameIn));
+}
+
+bool CreateFilterPreset::workToBeDone()
+{
+	return true;
+}
+
+void CreateFilterPreset::redo()
+{
+	index = createFilterPreset(name, data);
+}
+
+void CreateFilterPreset::undo()
+{
+	// with std::tie() we can conveniently assign tuples
+	std::tie(name, data) = removeFilterPreset(index);
+}
+
+RemoveFilterPreset::RemoveFilterPreset(int indexIn) : index(indexIn)
+{
+	setText(Command::Base::tr("Delete filter preset %1").arg(filter_preset_name_qstring(index)));
+}
+
+bool RemoveFilterPreset::workToBeDone()
+{
+	return true;
+}
+
+void RemoveFilterPreset::redo()
+{
+	// with std::tie() we can conveniently assign tuples
+	std::tie(name, data) = removeFilterPreset(index);
+}
+
+void RemoveFilterPreset::undo()
+{
+	index = createFilterPreset(name, data);
+}
+
+EditFilterPreset::EditFilterPreset(int indexIn, const FilterData &dataIn) :
+	index(indexIn), data(dataIn)
+{
+	setText(Command::Base::tr("Edit filter preset %1").arg(filter_preset_name_qstring(index)));
+}
+
+bool EditFilterPreset::workToBeDone()
+{
+	return true;
+}
+
+void EditFilterPreset::redo()
+{
+	FilterData oldData = filter_preset_get(index);
+	filter_preset_set(index, data);
+	data = std::move(oldData);
+}
+
+void EditFilterPreset::undo()
+{
+	redo(); // undo() and redo() do the same thing
+}
+
+} // namespace Command