MR::Historian< HistoryActionType > Class Template Reference

#include <MRViewer/MRAppendHistory.h>

Public Types
using	Obj = typename HistoryActionType::Obj

Public Member Functions
template<typename... Args>
	Historian (std::string name, std::shared_ptr< Obj > obj, Args &&... args)
void	cancelAction ()
	~Historian ()

Detailed Description

template<class HistoryActionType>
class MR::Historian< HistoryActionType >

The main objective of this class is to save object's state in the constructor, then let the caller modify object's data in-place, and finally append the action in the history store and automatically call appropriate setDirty in the destructor. If HistoryStore::getViewerInstance() is missing, it does not allocate memory for undo (the action is not created at all). If the operation fails midway, call cancelAction() to revert the modifications made so far and to skip both appending in the history store and setDirty in the destructor. If the new state is already allocated, then AppendHistory with immediate-setting action constructor is a simpler alternative (no memory waste anyway, since such constructors keep the old state for undo via swap). Always create a named Historian variable and never a nameless temporary such as Historian<ChangeMeshPointsAction>( "name", obj ); because a temporary is destroyed at the end of the same statement, calling setDirty before any data modification; the constructor is marked [[nodiscard]] so a discarded temporary produces a compiler warning (an error with -Werror / /WX).

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The documentation for this class was generated from the following file:

• MRViewer/MRAppendHistory.h