Files
mod-playerbots/src/strategy/druid/CasterDruidStrategy.cpp
Nicolas Lebacq c9cc4324d3 NextAction refactoring to eliminate sentinel arrays and pointers (#1923)
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# 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.
2026-01-06 12:37:39 +01:00

255 lines
6.4 KiB
C++

/*
* Copyright (C) 2016+ AzerothCore <www.azerothcore.org>, released under GNU AGPL v3 license, you may redistribute it
* and/or modify it under version 3 of the License, or (at your option), any later version.
*/
#include "CasterDruidStrategy.h"
#include "AiObjectContext.h"
#include "FeralDruidStrategy.h"
class CasterDruidStrategyActionNodeFactory : public NamedObjectFactory<ActionNode>
{
public:
CasterDruidStrategyActionNodeFactory()
{
creators["faerie fire"] = &faerie_fire;
creators["hibernate"] = &hibernate;
creators["entangling roots"] = &entangling_roots;
creators["entangling roots on cc"] = &entangling_roots_on_cc;
creators["wrath"] = &wrath;
creators["starfall"] = &starfall;
creators["insect swarm"] = &insect_swarm;
creators["moonfire"] = &moonfire;
creators["starfire"] = &starfire;
creators["moonkin form"] = &moonkin_form;
}
private:
static ActionNode* faerie_fire([[maybe_unused]] PlayerbotAI* botAI)
{
return new ActionNode(
"faerie fire",
/*P*/ { NextAction("moonkin form") },
/*A*/ {},
/*C*/ {}
);
}
static ActionNode* hibernate([[maybe_unused]] PlayerbotAI* botAI)
{
return new ActionNode(
"hibernate",
/*P*/ { NextAction("moonkin form") },
/*A*/ { NextAction("entangling roots") },
/*C*/ {}
);
}
static ActionNode* entangling_roots([[maybe_unused]] PlayerbotAI* botAI)
{
return new ActionNode(
"entangling roots",
/*P*/ { NextAction("moonkin form") },
/*A*/ {},
/*C*/ {}
);
}
static ActionNode* entangling_roots_on_cc([[maybe_unused]] PlayerbotAI* botAI)
{
return new ActionNode(
"entangling roots on cc",
/*P*/ { NextAction("moonkin form") },
/*A*/ {},
/*C*/ {}
);
}
static ActionNode* wrath([[maybe_unused]] PlayerbotAI* botAI)
{
return new ActionNode(
"wrath",
/*P*/ { NextAction("moonkin form") },
/*A*/ {},
/*C*/ {}
);
}
static ActionNode* starfall([[maybe_unused]] PlayerbotAI* botAI)
{
return new ActionNode(
"starfall",
/*P*/ { NextAction("moonkin form") },
/*A*/ {},
/*C*/ {}
);
}
static ActionNode* insect_swarm([[maybe_unused]] PlayerbotAI* botAI)
{
return new ActionNode(
"insect swarm",
/*P*/ { NextAction("moonkin form") },
/*A*/ {},
/*C*/ {}
);
}
static ActionNode* moonfire([[maybe_unused]] PlayerbotAI* botAI)
{
return new ActionNode(
"moonfire",
/*P*/ { NextAction("moonkin form") },
/*A*/ {},
/*C*/ {}
);
}
static ActionNode* starfire([[maybe_unused]] PlayerbotAI* botAI)
{
return new ActionNode(
"starfire",
/*P*/ { NextAction("moonkin form") },
/*A*/ {},
/*C*/ {}
);
}
static ActionNode* moonkin_form([[maybe_unused]] PlayerbotAI* botAI)
{
return new ActionNode(
"moonkin form",
/*P*/ { NextAction("caster form") },
/*A*/ {},
/*C*/ {}
);
}
};
CasterDruidStrategy::CasterDruidStrategy(PlayerbotAI* botAI) : GenericDruidStrategy(botAI)
{
actionNodeFactories.Add(new CasterDruidStrategyActionNodeFactory());
actionNodeFactories.Add(new ShapeshiftDruidStrategyActionNodeFactory());
}
std::vector<NextAction> CasterDruidStrategy::getDefaultActions()
{
return {
NextAction("starfall", ACTION_HIGH + 1.0f),
NextAction("force of nature", ACTION_DEFAULT + 1.0f),
NextAction("wrath", ACTION_DEFAULT + 0.1f),
};
}
void CasterDruidStrategy::InitTriggers(std::vector<TriggerNode*>& triggers)
{
GenericDruidStrategy::InitTriggers(triggers);
triggers.push_back(
new TriggerNode(
"eclipse (lunar) cooldown",
{
NextAction("starfire", ACTION_DEFAULT + 0.2f)
}
)
);
triggers.push_back(
new TriggerNode(
"eclipse (solar) cooldown",
{
NextAction("wrath", ACTION_DEFAULT + 0.2f)
}
)
);
triggers.push_back(
new TriggerNode(
"insect swarm",
{
NextAction("insect swarm", ACTION_NORMAL + 5)
}
)
);
triggers.push_back(
new TriggerNode(
"moonfire",
{
NextAction("moonfire", ACTION_NORMAL + 4)
}
)
);
triggers.push_back(
new TriggerNode(
"eclipse (solar)",
{
NextAction("wrath", ACTION_NORMAL + 6)
}
)
);
triggers.push_back(
new TriggerNode(
"eclipse (lunar)",
{
NextAction("starfire", ACTION_NORMAL + 6)
}
)
);
triggers.push_back(
new TriggerNode(
"medium mana",
{
NextAction("innervate", ACTION_HIGH + 9)
}
)
);
triggers.push_back(
new TriggerNode(
"enemy too close for spell",
{
NextAction("flee", ACTION_MOVE + 9)
}
)
);
}
void CasterDruidAoeStrategy::InitTriggers(std::vector<TriggerNode*>& triggers)
{
triggers.push_back(
new TriggerNode(
"hurricane channel check",
{
NextAction("cancel channel", ACTION_HIGH + 2)
}
)
);
triggers.push_back(
new TriggerNode(
"medium aoe",
{
NextAction("hurricane", ACTION_HIGH + 1)
}
)
);
triggers.push_back(
new TriggerNode(
"light aoe",
{
NextAction("insect swarm on attacker", ACTION_NORMAL + 3),
NextAction("moonfire on attacker", ACTION_NORMAL + 3)
}
)
);
}
void CasterDruidDebuffStrategy::InitTriggers(std::vector<TriggerNode*>& triggers)
{
triggers.push_back(
new TriggerNode(
"faerie fire",
{
NextAction("faerie fire", ACTION_HIGH)
}
)
);
}