sneedmc/launcher/Usable.h

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#pragma once
#include <cstddef>
#include <memory>
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#include "QObjectPtr.h"
class Usable;
/**
* Base class for things that can be used by multiple other things and we want to track the use count.
*
* @see UseLock
*/
class Usable
{
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friend class UseLock;
public:
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std::size_t useCount() const
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{
return m_useCount;
}
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bool isInUse() const
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{
return m_useCount > 0;
}
protected:
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virtual void decrementUses()
{
m_useCount--;
}
virtual void incrementUses()
{
m_useCount++;
}
private:
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std::size_t m_useCount = 0;
};
/**
* Lock class to use for keeping track of uses of other things derived from Usable
*
* @see Usable
*/
class UseLock
{
public:
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UseLock(shared_qobject_ptr<Usable> usable)
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: m_usable(usable)
{
// this doesn't use shared pointer use count, because that wouldn't be correct. this count is separate.
m_usable->incrementUses();
}
~UseLock()
{
m_usable->decrementUses();
}
private:
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shared_qobject_ptr<Usable> m_usable;
};