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2020-08-04 13:13:01 -04:00

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//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose: An application framework
//
// $Revision: $
// $NoKeywords: $
//=============================================================================//
#ifndef IAPPSYSTEM_H
#define IAPPSYSTEM_H
#ifdef _WIN32
#pragma once
#endif
#include "../tier1/interface.h"
//-----------------------------------------------------------------------------
// Client systems are singleton objects in the client codebase responsible for
// various tasks
// The order in which the client systems appear in this list are the
// order in which they are initialized and updated. They are shut down in
// reverse order from which they are initialized.
//-----------------------------------------------------------------------------
enum InitReturnVal_t {
INIT_FAILED = 0,
INIT_OK,
INIT_LAST_VAL,
};
abstract_class IAppSystem {
public:
// Here's where the app systems get to learn about each other
virtual bool Connect(CreateInterfaceFn factory) = 0;
virtual void Disconnect() = 0;
// Here's where systems can access other interfaces implemented by this
// object Returns NULL if it doesn't implement the requested interface
virtual void *QueryInterface(const char *pInterfaceName) = 0;
// Init, shutdown
virtual InitReturnVal_t Init() = 0;
virtual void Shutdown() = 0;
};
//-----------------------------------------------------------------------------
// Helper empty implementation of an IAppSystem
//-----------------------------------------------------------------------------
template <class IInterface>
class CBaseAppSystem : public IInterface {
public:
// Here's where the app systems get to learn about each other
virtual bool Connect(CreateInterfaceFn factory) { return true; }
virtual void Disconnect() {}
// Here's where systems can access other interfaces implemented by this
// object Returns NULL if it doesn't implement the requested interface
virtual void *QueryInterface(const char *pInterfaceName) { return NULL; }
// Init, shutdown
virtual InitReturnVal_t Init() { return INIT_OK; }
virtual void Shutdown() {}
};
//-----------------------------------------------------------------------------
// Helper implementation of an IAppSystem for tier0
//-----------------------------------------------------------------------------
template <class IInterface>
class CTier0AppSystem : public CBaseAppSystem<IInterface> {
public:
CTier0AppSystem(bool bIsPrimaryAppSystem = true) {
m_bIsPrimaryAppSystem = bIsPrimaryAppSystem;
}
protected:
// NOTE: a single DLL may have multiple AppSystems it's trying to
// expose. If this is true, you must return true from only
// one of those AppSystems; not doing so will cause all static
// libraries connected to it to connect/disconnect multiple times
// NOTE: We don't do this as a virtual function to avoid
// having to up the version on all interfaces
bool IsPrimaryAppSystem() { return m_bIsPrimaryAppSystem; }
private:
bool m_bIsPrimaryAppSystem;
};
//-----------------------------------------------------------------------------
// This is the version of IAppSystem shipped 10/15/04
// NOTE: Never change this!!!
//-----------------------------------------------------------------------------
abstract_class IAppSystemV0 {
public:
// Here's where the app systems get to learn about each other
virtual bool Connect(CreateInterfaceFn factory) = 0;
virtual void Disconnect() = 0;
// Here's where systems can access other interfaces implemented by this
// object Returns NULL if it doesn't implement the requested interface
virtual void *QueryInterface(const char *pInterfaceName) = 0;
// Init, shutdown
virtual InitReturnVal_t Init() = 0;
virtual void Shutdown() = 0;
};
#endif // IAPPSYSTEM_H