Files
mod-playerbots/src/strategy/dungeons/wotlk/utgardekeep/UtgardeKeepStrategy.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

43 lines
2.0 KiB
C++

#include "UtgardeKeepStrategy.h"
#include "UtgardeKeepMultipliers.h"
void WotlkDungeonUKStrategy::InitTriggers(std::vector<TriggerNode*> &triggers)
{
// Prince Keleseth
triggers.push_back(new TriggerNode("keleseth frost tomb",
{ NextAction("attack frost tomb", ACTION_RAID + 1) }));
// Skarvald the Constructor & Dalronn the Controller
triggers.push_back(new TriggerNode("dalronn priority",
{ NextAction("attack dalronn", ACTION_RAID + 1) }));
// Ingvar the Plunderer
// Doesn't work yet, this action doesn't get processed until the existing cast finishes
// triggers.push_back(new TriggerNode("ingvar staggering roar",
// { NextAction("ingvar stop casting", ACTION_RAID + 1) }));
// No easy way to check LoS here, the pillars do not seem to count as gameobjects.
// Not implemented for now, unsure if this is needed as a good group can probably burst through the boss
// and just eat the debuff.
// triggers.push_back(new TriggerNode("ingvar dreadful roar",
// { NextAction("ingvar hide los", ACTION_RAID + 1) }));
triggers.push_back(new TriggerNode("ingvar smash tank",
{ NextAction("ingvar dodge smash", ACTION_MOVE + 5) }));
triggers.push_back(new TriggerNode("ingvar smash tank return",
{ NextAction("ingvar smash return", ACTION_MOVE + 5) }));
// Buggy... if not behind target, ai can get stuck running towards and away from target.
// I think for ranged chars, a custom action should be added that doesn't attempt to run into melee.
// This is a bandaid for now, needs to be improved.
triggers.push_back(new TriggerNode("not behind ingvar",
{ NextAction("set behind", ACTION_MOVE + 1) }));
}
void WotlkDungeonUKStrategy::InitMultipliers(std::vector<Multiplier*> &multipliers)
{
multipliers.push_back(new PrinceKelesethMultiplier(botAI));
multipliers.push_back(new SkarvaldAndDalronnMultiplier(botAI));
multipliers.push_back(new IngvarThePlundererMultiplier(botAI));
}