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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.
This commit is contained in:
Nicolas Lebacq
2026-01-06 11:37:39 +00:00
committed by GitHub
parent b13fb7d12a
commit c9cc4324d3
197 changed files with 6795 additions and 4054 deletions
Download Patch File Download Diff File Expand all files Collapse all files

158
src/strategy/deathknight/BloodDKStrategy.cpp
View File

@@ -12,25 +12,10 @@ class BloodDKStrategyActionNodeFactory : public NamedObjectFactory<ActionNode>
public:
BloodDKStrategyActionNodeFactory()
{
// creators["melee"] = &melee;
// creators["blood strike"] = &blood_strike;
creators["rune strike"] = &rune_strike;
creators["heart strike"] = &heart_strike;
creators["death strike"] = &death_strike;
// creators["death grip"] = &death_grip;
// creators["plague strike"] = &plague_strike;
// creators["pestilence"] = &pestilence;
creators["icy touch"] = &icy_touch;
// creators["obliterate"] = &obliterate;
// creators["blood boil"] = &blood_boil;
// creators["mark of_blood"] = &mark_of_blood;
// creators["blood presence"] = &blood_presence;
// creators["rune tap"] = &rune_tap;
// creators["vampiric blood"] = &vampiric_blood;
// creators["death pact"] = &death_pact;
// creators["death rune_mastery"] = &death_rune_mastery;
// creators["hysteria"] = &hysteria;
// creators["dancing weapon"] = &dancing_weapon;
creators["dark command"] = &dark_command;
creators["taunt spell"] = &dark_command;
}
@@ -38,39 +23,61 @@ public:
private:
static ActionNode* rune_strike([[maybe_unused]] PlayerbotAI* botAI)
{
return new ActionNode("rune strike",
/*P*/ NextAction::array(0, new NextAction("frost presence"), nullptr),
/*A*/ nullptr,
/*C*/ nullptr);
return new ActionNode(
"rune strike",
{
NextAction("frost presence")
},
/*A*/ {},
/*C*/ {}
);
}
static ActionNode* icy_touch([[maybe_unused]] PlayerbotAI* botAI)
{
return new ActionNode("icy touch",
/*P*/ NextAction::array(0, new NextAction("frost presence"), nullptr),
/*A*/ nullptr,
/*C*/ nullptr);
return new ActionNode(
"icy touch",
{
NextAction("frost presence")
},
/*A*/ {},
/*C*/ {}
);
}
static ActionNode* heart_strike([[maybe_unused]] PlayerbotAI* botAI)
{
return new ActionNode("heart strike",
/*P*/ NextAction::array(0, new NextAction("frost presence"), nullptr),
/*A*/ nullptr,
/*C*/ nullptr);
return new ActionNode(
"heart strike",
{
NextAction("frost presence")
},
/*A*/ {},
/*C*/ {}
);
}
static ActionNode* death_strike([[maybe_unused]] PlayerbotAI* botAI)
{
return new ActionNode("death strike",
/*P*/ NextAction::array(0, new NextAction("frost presence"), nullptr),
/*A*/ nullptr,
/*C*/ nullptr);
return new ActionNode(
"death strike",
{
NextAction("frost presence")
},
/*A*/ {},
/*C*/ {}
);
}
static ActionNode* dark_command([[maybe_unused]] PlayerbotAI* botAI)
{
return new ActionNode("dark command",
/*P*/ NextAction::array(0, new NextAction("frost presence"), NULL),
/*A*/ NextAction::array(0, new NextAction("death grip"), NULL),
/*C*/ NULL);
return new ActionNode(
"dark command",
{
NextAction("frost presence")
},
/*A*/ {
NextAction("death grip")
},
/*C*/ {}
);
}
};
@@ -79,33 +86,80 @@ BloodDKStrategy::BloodDKStrategy(PlayerbotAI* botAI) : GenericDKStrategy(botAI)
actionNodeFactories.Add(new BloodDKStrategyActionNodeFactory());
}
NextAction** BloodDKStrategy::getDefaultActions()
std::vector<NextAction> BloodDKStrategy::getDefaultActions()
{
return NextAction::array(
0, new NextAction("rune strike", ACTION_DEFAULT + 0.8f), new NextAction("icy touch", ACTION_DEFAULT + 0.7f),
new NextAction("heart strike", ACTION_DEFAULT + 0.6f), new NextAction("blood strike", ACTION_DEFAULT + 0.5f),
new NextAction("dancing rune weapon", ACTION_DEFAULT + 0.4f),
new NextAction("death coil", ACTION_DEFAULT + 0.3f), new NextAction("plague strike", ACTION_DEFAULT + 0.2f),
new NextAction("horn of winter", ACTION_DEFAULT + 0.1f), new NextAction("melee", ACTION_DEFAULT), NULL);
return {
NextAction("rune strike", ACTION_DEFAULT + 0.8f),
NextAction("icy touch", ACTION_DEFAULT + 0.7f),
NextAction("heart strike", ACTION_DEFAULT + 0.6f),
NextAction("blood strike", ACTION_DEFAULT + 0.5f),
NextAction("dancing rune weapon", ACTION_DEFAULT + 0.4f),
NextAction("death coil", ACTION_DEFAULT + 0.3f),
NextAction("plague strike", ACTION_DEFAULT + 0.2f),
NextAction("horn of winter", ACTION_DEFAULT + 0.1f),
NextAction("melee", ACTION_DEFAULT)
};
}
void BloodDKStrategy::InitTriggers(std::vector<TriggerNode*>& triggers)
{
GenericDKStrategy::InitTriggers(triggers);
triggers.push_back(new TriggerNode(
"rune strike", NextAction::array(0, new NextAction("rune strike", ACTION_NORMAL + 3), nullptr)));
triggers.push_back(
new TriggerNode("blood tap", NextAction::array(0, new NextAction("blood tap", ACTION_HIGH + 5), nullptr)));
new TriggerNode(
"rune strike",
{
NextAction("rune strike", ACTION_NORMAL + 3)
}
)
);
triggers.push_back(
new TriggerNode("lose aggro", NextAction::array(0, new NextAction("dark command", ACTION_HIGH + 3), nullptr)));
new TriggerNode(
"blood tap",
{
NextAction("blood tap", ACTION_HIGH + 5)
}
)
);
triggers.push_back(
new TriggerNode("low health", NextAction::array(0, new NextAction("army of the dead", ACTION_HIGH + 4),
new NextAction("death strike", ACTION_HIGH + 3), nullptr)));
new TriggerNode(
"lose aggro",
{
NextAction("dark command", ACTION_HIGH + 3)
}
)
);
triggers.push_back(
new TriggerNode("critical health", NextAction::array(0, new NextAction("vampiric blood", ACTION_HIGH + 5), nullptr)));
new TriggerNode(
"low health",
{
NextAction("army of the dead", ACTION_HIGH + 4),
NextAction("death strike", ACTION_HIGH + 3)
}
)
);
triggers.push_back(
new TriggerNode("icy touch", NextAction::array(0, new NextAction("icy touch", ACTION_HIGH + 2), nullptr)));
triggers.push_back(new TriggerNode(
"plague strike", NextAction::array(0, new NextAction("plague strike", ACTION_HIGH + 2), nullptr)));
new TriggerNode(
"critical health",
{
NextAction("vampiric blood", ACTION_HIGH + 5)
}
)
);
triggers.push_back(
new TriggerNode(
"icy touch",
{
NextAction("icy touch", ACTION_HIGH + 2)
}
)
);
triggers.push_back(
new TriggerNode(
"plague strike",
{
NextAction("plague strike", ACTION_HIGH + 2)
}
)
);
}