undo: implement gas switch

This is a bit hairy as - in theory - one gas switch can remove
other gas switch(es) at the same timestamp. However, I did not
find a way to test it. Moreover, it is not clear whether the
dive-tabs are properly updated on undo/redo.

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

1 files changed, 13 insertions, 0 deletions

diff --git a/commands/command_event.h b/commands/command_event.h
index eec5cb262..8e75dee6c 100644
--- a/commands/command_event.h
+++ b/commands/command_event.h
@@ -82,6 +82,19 @@ private:
 	event *eventToRemove;		// for redo
 };
 
+class AddGasSwitch : public EventBase {
+public:
+	AddGasSwitch(struct dive *d, int dcNr, int seconds, int tank);
+private:
+	bool workToBeDone() override;
+	void undoit() override;
+	void redoit() override;
+
+	std::vector<int> cylinders; // cylinders that are modified
+	std::vector<OwningEventPtr> eventsToAdd;
+	std::vector<event *> eventsToRemove;
+};
+
 } // namespace Command
 
 #endif // COMMAND_EVENT_H