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UndoFileChangeTracker.h
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/
UndoFileChangeTracker.h
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#pragma once
#include "iundo.h"
#include "imapfilechangetracker.h"
#include <limits>
#include <sigc++/signal.h>
class UndoFileChangeTracker :
public IMapFileChangeTracker
{
private:
constexpr static std::size_t MAPFILE_MAX_CHANGES = std::numeric_limits<std::size_t>::max();
std::size_t _currentChangeCount;
std::size_t _savedChangeCount;
sigc::signal<void()> _changed;
public:
UndoFileChangeTracker() :
_currentChangeCount(0),
_savedChangeCount(MAPFILE_MAX_CHANGES)
{}
void setSavedChangeCount() override
{
_savedChangeCount = _currentChangeCount;
_changed.emit();
}
// Returns true if the current undo history position corresponds to the most recently saved state
bool isAtSavedPosition() const override
{
return _savedChangeCount == _currentChangeCount;
}
sigc::signal<void()>& signal_changed() override
{
return _changed;
}
std::size_t getCurrentChangeCount() const override
{
return _currentChangeCount;
}
void onUndoEvent(IUndoSystem::EventType type, const std::string& operationName)
{
switch (type)
{
case IUndoSystem::EventType::OperationRecorded:
if (_currentChangeCount < _savedChangeCount)
{
// redo queue has been flushed.. it is now impossible to get back to the saved state via undo/redo
_savedChangeCount = MAPFILE_MAX_CHANGES;
}
++_currentChangeCount;
break;
case IUndoSystem::EventType::OperationUndone:
--_currentChangeCount;
break;
case IUndoSystem::EventType::OperationRedone:
++_currentChangeCount;
break;
case IUndoSystem::EventType::AllOperationsCleared:
_currentChangeCount = 0;
break;
}
_changed.emit();
}
};