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https://github.com/liyunfan1223/mod-playerbots.git
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c9cc4324d3
<!-- > [!WARNING] > **This is a DRAFT PR.** > The structure is not definitive. The code might not be optimised yet. It might not even start nor compile yet. > **Don't panic. ✋ It's going to be ok. 👌 We can make modifications, we can fix things.** 😁 --> # Description This PR aims to refactor the NextAction declaration to achieve two goals: ## Eliminate C-style sentinel arrays Currently, a double pointer (`NextAction**`) approach is being used. This an old pre-C++11 (< 2011) trick before `std::vector<>` became a thing. This approach is painful for developers because they constantly need to declare their `NextAction` arrays as: ```cpp NextAction::array(0, new NextAction("foo", 1.0f), nullptr) ``` Instead of: ```cpp { new NextAction("foo", 1.0f) } ``` The first argument of `NextAction::array` is actually a hack. It is used to have a named argument so `va_args` can find the remaining arguments. It is set to 0 everywhere but in fact does nothing. This is very confusing to people unfamiliar with this antiquated syntax. The last argument `nullptr` is what we call a sentinel. It's a `nullptr` because `va_args` is looking for a `nullptr` to stop iterating. It's also a hack and also leads to confusion. ## Eliminate unnecessary pointers for `NextAction` Pointers can be used for several reasons, to cite a few: - Indicate strong, absolute identity. - Provide strong but transferable ownership (unlike references). - When a null value is acceptable (`nullptr`). - When copy is expensive. `NextAction` meets none of these criteria: - It has no identity because it is purely behavioural. - It is never owned by anything as it is passed around and never fetched from a registry. - The only situations where it can be `nullptr` are errors that should in fact throw an `std::invalid_argument` instead. - They are extremely small objects that embark a single `std::string` and a single `float`. Pointers should be avoided when not strictly necessary because they can quickly lead to undefined behaviour due to unhandled `nullptr` situations. They also make the syntax heavier due to the necessity to constantly check for `nullptr`. Finally, they aren't even good for performance in that situation because shifting a pointer so many times is likely more expensive than copying such a trivial object. # End goal The end goal is to declare `NextAction` arrays this way: ```cpp { NextAction("foo", 1.0f) } ``` > [!NOTE] > Additional note: `NextAction` is nothing but a hacky proxy to an `Action` constructor. This should eventually be reworked to use handles instead of strings. This would make copying `NextAction` even cheaper and remove the need for the extremely heavy stringly typed current approach. Stringly typed entities are a known anti-pattern so we need to move on from those.
84 lines
2.2 KiB
C++
84 lines
2.2 KiB
C++
/*
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* Copyright (C) 2016+ AzerothCore <www.azerothcore.org>, released under GNU AGPL v3 license, you may redistribute it
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* and/or modify it under version 3 of the License, or (at your option), any later version.
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*/
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#ifndef _PLAYERBOT_DRUIDSHAPESHIFTACTIONS_H
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#define _PLAYERBOT_DRUIDSHAPESHIFTACTIONS_H
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#include "GenericSpellActions.h"
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class PlayerbotAI;
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class CastBearFormAction : public CastBuffSpellAction
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{
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public:
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CastBearFormAction(PlayerbotAI* botAI) : CastBuffSpellAction(botAI, "bear form") {}
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bool isPossible() override;
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bool isUseful() override;
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};
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class CastDireBearFormAction : public CastBuffSpellAction
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{
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public:
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CastDireBearFormAction(PlayerbotAI* botAI) : CastBuffSpellAction(botAI, "dire bear form") {}
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std::vector<NextAction> getAlternatives() override;
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};
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class CastCatFormAction : public CastBuffSpellAction
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{
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public:
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CastCatFormAction(PlayerbotAI* botAI) : CastBuffSpellAction(botAI, "cat form") {}
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};
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class CastTreeFormAction : public CastBuffSpellAction
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{
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public:
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CastTreeFormAction(PlayerbotAI* botAI) : CastBuffSpellAction(botAI, "tree of life") {}
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bool isUseful() override;
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};
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class CastMoonkinFormAction : public CastBuffSpellAction
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{
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public:
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CastMoonkinFormAction(PlayerbotAI* botAI) : CastBuffSpellAction(botAI, "moonkin form") {}
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};
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class CastAquaticFormAction : public CastBuffSpellAction
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{
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public:
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CastAquaticFormAction(PlayerbotAI* botAI) : CastBuffSpellAction(botAI, "aquatic form") {}
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};
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class CastTravelFormAction : public CastBuffSpellAction
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{
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public:
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CastTravelFormAction(PlayerbotAI* botAI) : CastBuffSpellAction(botAI, "travel form") {}
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bool isUseful() override;
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};
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class CastCasterFormAction : public CastBuffSpellAction
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{
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public:
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CastCasterFormAction(PlayerbotAI* botAI) : CastBuffSpellAction(botAI, "caster form") {}
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bool isUseful() override;
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bool isPossible() override { return true; }
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bool Execute(Event event) override;
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};
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class CastCancelTreeFormAction : public CastBuffSpellAction
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{
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public:
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CastCancelTreeFormAction(PlayerbotAI* botAI) : CastBuffSpellAction(botAI, "cancel tree form") {}
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bool isUseful() override;
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bool isPossible() override { return true; }
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bool Execute(Event event) override;
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};
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#endif
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