240 lines
8.9 KiB
C++
Executable File
240 lines
8.9 KiB
C++
Executable File
/**
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* @file lldoubledispatch_tut.cpp
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* @author Nat Goodspeed
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* @date 2008-11-13
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* @brief Test for lldoubledispatch.h
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*
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* This program tests the DoubleDispatch class, using a variation on the example
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* from Scott Meyers' "More Effective C++", Item 31.
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*
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* $LicenseInfo:firstyear=2008&license=viewerlgpl$
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* Second Life Viewer Source Code
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* Copyright (C) 2010, Linden Research, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation;
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* version 2.1 of the License only.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
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* $/LicenseInfo$
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*/
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// Precompiled header
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#include "linden_common.h"
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// associated header
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#include "lldoubledispatch.h"
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// STL headers
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// std headers
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#include <string>
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#include <iostream>
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#include <typeinfo>
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// external library headers
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// other Linden headers
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#include "lltut.h"
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/*---------------------------- Class hierarchy -----------------------------*/
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// All objects are GameObjects.
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class GameObject
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{
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public:
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GameObject(const std::string& name): mName(name) {}
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virtual ~GameObject() {}
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virtual std::string stringize() { return std::string(typeid(*this).name()) + " " + mName; }
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protected:
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std::string mName;
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};
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// SpaceStation, Asteroid and SpaceShip are peer GameObjects.
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struct SpaceStation: public GameObject
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{
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SpaceStation(const std::string& name): GameObject(name) {}
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// Only a dummy SpaceStation is constructed without a name
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SpaceStation(): GameObject("dummy") {}
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};
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struct Asteroid: public GameObject
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{
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Asteroid(const std::string& name): GameObject(name) {}
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Asteroid(): GameObject("dummy") {}
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};
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struct SpaceShip: public GameObject
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{
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SpaceShip(const std::string& name): GameObject(name) {}
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SpaceShip(): GameObject("dummy") {}
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};
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// SpaceShip is specialized further into CommercialShip and MilitaryShip.
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struct CommercialShip: public SpaceShip
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{
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CommercialShip(const std::string& name): SpaceShip(name) {}
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CommercialShip(): SpaceShip("dummy") {}
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};
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struct MilitaryShip: public SpaceShip
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{
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MilitaryShip(const std::string& name): SpaceShip(name) {}
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MilitaryShip(): SpaceShip("dummy") {}
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};
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/*-------------------------- Collision functions ---------------------------*/
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// This mechanism permits us to overcome a limitation of Meyers' approach: we
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// can declare the parameter types exactly as we want, rather than having to
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// make them all GameObject& parameters.
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std::string shipAsteroid(SpaceShip& ship, Asteroid& rock)
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{
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// std::cout << rock.stringize() << " has pulverized " << ship.stringize() << std::endl;
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return "shipAsteroid";
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}
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std::string militaryShipAsteroid(MilitaryShip& ship, Asteroid& rock)
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{
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// std::cout << rock.stringize() << " has severely damaged " << ship.stringize() << std::endl;
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return "militaryShipAsteroid";
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}
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std::string shipStation(SpaceShip& ship, SpaceStation& dock)
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{
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// std::cout << ship.stringize() << " has docked at " << dock.stringize() << std::endl;
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return "shipStation";
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}
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std::string asteroidStation(Asteroid& rock, SpaceStation& dock)
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{
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// std::cout << rock.stringize() << " has damaged " << dock.stringize() << std::endl;
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return "asteroidStation";
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}
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/*------------------------------- Test code --------------------------------*/
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namespace tut
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{
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struct dispatch_data
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{
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dispatch_data():
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home(new SpaceStation("Terra Station")),
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obstacle(new Asteroid("Ganymede")),
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tug(new CommercialShip("Pilotfish")),
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patrol(new MilitaryShip("Enterprise"))
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{}
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// Instantiate and populate the DoubleDispatch object.
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typedef LLDoubleDispatch<std::string, GameObject> DD;
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DD dispatcher;
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// Instantiate a few GameObjects. Make sure we refer to them
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// polymorphically, and don't let them leak.
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std::auto_ptr<GameObject> home;
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std::auto_ptr<GameObject> obstacle;
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std::auto_ptr<GameObject> tug;
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std::auto_ptr<GameObject> patrol;
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// prototype objects
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Asteroid dummyAsteroid;
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SpaceShip dummyShip;
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MilitaryShip dummyMilitary;
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CommercialShip dummyCommercial;
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SpaceStation dummyStation;
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};
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typedef test_group<dispatch_data> dispatch_group;
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typedef dispatch_group::object dispatch_object;
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tut::dispatch_group ddgr("double dispatch");
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template<> template<>
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void dispatch_object::test<1>()
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{
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// Describe param types using explicit DD::Type objects
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// (order-sensitive add() variant)
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dispatcher.add(DD::Type<SpaceShip>(), DD::Type<Asteroid>(), shipAsteroid, true);
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// naive adding, won't work
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dispatcher.add(DD::Type<MilitaryShip>(), DD::Type<Asteroid>(), militaryShipAsteroid, true);
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dispatcher.add(DD::Type<SpaceShip>(), DD::Type<SpaceStation>(), shipStation, true);
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dispatcher.add(DD::Type<Asteroid>(), DD::Type<SpaceStation>(), asteroidStation, true);
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// Try colliding them.
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ensure_equals(dispatcher(*home, *tug), // reverse params, SpaceShip subclass
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"shipStation");
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ensure_equals(dispatcher(*patrol, *home), // forward params, SpaceShip subclass
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"shipStation");
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ensure_equals(dispatcher(*obstacle, *home), // forward params
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"asteroidStation");
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ensure_equals(dispatcher(*home, *obstacle), // reverse params
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"asteroidStation");
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ensure_equals(dispatcher(*tug, *obstacle), // forward params, SpaceShip subclass
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"shipAsteroid");
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ensure_equals(dispatcher(*obstacle, *patrol), // reverse params, SpaceShip subclass
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// won't use militaryShipAsteroid() because it was added
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// in wrong order
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"shipAsteroid");
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}
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template<> template<>
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void dispatch_object::test<2>()
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{
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// Describe param types using explicit DD::Type objects
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// (order-sensitive add() variant)
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// adding in correct order
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dispatcher.add(DD::Type<MilitaryShip>(), DD::Type<Asteroid>(), militaryShipAsteroid, true);
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dispatcher.add(DD::Type<SpaceShip>(), DD::Type<Asteroid>(), shipAsteroid, true);
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dispatcher.add(DD::Type<SpaceShip>(), DD::Type<SpaceStation>(), shipStation, true);
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dispatcher.add(DD::Type<Asteroid>(), DD::Type<SpaceStation>(), asteroidStation, true);
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ensure_equals(dispatcher(*patrol, *obstacle), "militaryShipAsteroid");
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ensure_equals(dispatcher(*tug, *obstacle), "shipAsteroid");
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}
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template<> template<>
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void dispatch_object::test<3>()
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{
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// Describe param types with actual prototype instances
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// (order-insensitive add() variant)
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dispatcher.add(dummyMilitary, dummyAsteroid, militaryShipAsteroid);
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dispatcher.add(dummyShip, dummyAsteroid, shipAsteroid);
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dispatcher.add(dummyShip, dummyStation, shipStation);
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dispatcher.add(dummyAsteroid, dummyStation, asteroidStation);
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ensure_equals(dispatcher(*patrol, *obstacle), "militaryShipAsteroid");
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ensure_equals(dispatcher(*tug, *obstacle), "shipAsteroid");
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ensure_equals(dispatcher(*obstacle, *patrol), "");
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}
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template<> template<>
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void dispatch_object::test<4>()
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{
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// Describe param types with actual prototype instances
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// (order-insensitive add() variant)
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dispatcher.add(dummyShip, dummyAsteroid, shipAsteroid);
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// Even if we add the militaryShipAsteroid in the wrong order, it
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// should still work.
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dispatcher.add(dummyMilitary, dummyAsteroid, militaryShipAsteroid);
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dispatcher.add(dummyShip, dummyStation, shipStation);
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dispatcher.add(dummyAsteroid, dummyStation, asteroidStation);
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ensure_equals(dispatcher(*patrol, *obstacle), "militaryShipAsteroid");
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ensure_equals(dispatcher(*tug, *obstacle), "shipAsteroid");
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}
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template<> template<>
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void dispatch_object::test<5>()
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{
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dispatcher.add<SpaceShip, Asteroid>(shipAsteroid);
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dispatcher.add<MilitaryShip, Asteroid>(militaryShipAsteroid);
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dispatcher.add<SpaceShip, SpaceStation>(shipStation);
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dispatcher.add<Asteroid, SpaceStation>(asteroidStation);
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ensure_equals(dispatcher(*patrol, *obstacle), "militaryShipAsteroid");
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ensure_equals(dispatcher(*tug, *obstacle), "shipAsteroid");
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}
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} // namespace tut
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