weakauras_codec_lua_value/

lib.rs

// Copyright 2020-2025 Velithris
// SPDX-License-Identifier: MIT

//! This library provides types that behave similarly to Lua types.
//!
//! # Crate features
//!
//! * **arbitrary** - Implement `arbitrary::Arbitrary` for [`LuaValue`]. **Disabled** by default.
//! * **fnv** - Use `fnv` instead of `BTreeMap` as the implementation of [`LuaValue::Map`]. **Disabled** by default.
//! * **indexmap** - Use `indexmap` instead of `BTreeMap` as the implementation of [`LuaValue::Map`]. **Disabled** by default.
//! * **serde** - Allow serializing and deserializing [`LuaValue`] using `serde`. **Disabled** by default.

#![deny(missing_docs)]

/// Error types.
pub mod error;

#[cfg(all(not(feature = "indexmap"), feature = "fnv"))]
pub use fnv::FnvHashMap as Map;
#[cfg(feature = "indexmap")]
pub use indexmap::IndexMap as Map;
#[cfg(not(any(feature = "indexmap", feature = "fnv")))]
pub use std::collections::BTreeMap as Map;

use crate::error::TryFromLuaValueError;
use core::convert::TryFrom;

#[cfg(feature = "arbitrary")]
use arbitrary::Arbitrary;
#[cfg(feature = "serde")]
use serde::{
    de::{self, Deserialize, Deserializer, MapAccess, SeqAccess, Visitor},
    ser::{Serialize, Serializer},
};

/// A tagged union representing all
/// possible values in Lua.
#[allow(missing_docs)] // Variants are self-explanatory.
#[derive(Debug, Clone)]
#[cfg_attr(feature = "arbitrary", derive(Arbitrary))]
pub enum LuaValue {
    Map(Map<LuaMapKey, LuaValue>),
    Array(Vec<LuaValue>),
    String(String),
    Number(f64),
    Boolean(bool),
    Null,
}

impl From<String> for LuaValue {
    fn from(value: String) -> Self {
        Self::String(value)
    }
}

impl From<&str> for LuaValue {
    fn from(value: &str) -> Self {
        Self::String(value.to_owned())
    }
}

impl From<&mut str> for LuaValue {
    fn from(value: &mut str) -> Self {
        Self::String(value.to_owned())
    }
}

impl From<f64> for LuaValue {
    fn from(value: f64) -> Self {
        Self::Number(value)
    }
}

impl From<bool> for LuaValue {
    fn from(value: bool) -> Self {
        Self::Boolean(value)
    }
}

/// A key of a Lua map.
#[repr(transparent)]
#[derive(Clone)]
pub struct LuaMapKey(LuaValue);
impl LuaMapKey {
    #[inline(always)]
    /// Get a reference to the underlying value.
    pub fn as_value(&self) -> &LuaValue {
        &self.0
    }
}

impl From<LuaMapKey> for LuaValue {
    fn from(value: LuaMapKey) -> Self {
        value.0
    }
}

impl TryFrom<LuaValue> for LuaMapKey {
    type Error = TryFromLuaValueError;

    fn try_from(value: LuaValue) -> Result<Self, Self::Error> {
        match value {
            LuaValue::Null => Err(TryFromLuaValueError::KeyCannotBeNull),
            LuaValue::Number(inner) if inner.is_nan() => Err(TryFromLuaValueError::KeyCannotBeNan),
            _ => Ok(Self(value)),
        }
    }
}

use core::hash::{Hash, Hasher};
impl Hash for LuaValue {
    fn hash<H: Hasher>(&self, state: &mut H) {
        match self {
            LuaValue::Map(m) => state.write_usize((m as *const Map<LuaMapKey, LuaValue>).addr()),
            LuaValue::Array(v) => state.write_usize((v as *const Vec<LuaValue>).addr()),
            LuaValue::String(s) => s.hash(state),
            LuaValue::Number(n) => state.write_u64(n.to_bits()),
            LuaValue::Boolean(b) => b.hash(state),
            LuaValue::Null => state.write_u8(0),
        }
    }
}

use core::cmp::Ordering;
impl PartialOrd for LuaValue {
    fn partial_cmp(&self, other: &LuaValue) -> Option<Ordering> {
        Some(self.cmp(other))
    }
}
impl Ord for LuaValue {
    // Number > String > Boolean > Map > Null
    fn cmp(&self, other: &LuaValue) -> Ordering {
        match (self, other) {
            (LuaValue::Number(n1), LuaValue::Number(n2)) => {
                n1.partial_cmp(n2)
                    .unwrap_or_else(|| match (n1.is_nan(), n2.is_nan()) {
                        (true, false) => Ordering::Less,
                        (false, true) => Ordering::Greater,
                        _ => Ordering::Equal,
                    })
            }
            (LuaValue::Number(_), _) => Ordering::Greater,
            (_, LuaValue::Number(_)) => Ordering::Less,
            (LuaValue::String(s1), LuaValue::String(s2)) => s1.cmp(s2),
            (LuaValue::String(_), LuaValue::Boolean(_))
            | (LuaValue::String(_), LuaValue::Map(_))
            | (LuaValue::String(_), LuaValue::Array(_)) => Ordering::Greater,
            (LuaValue::Boolean(_), LuaValue::String(_))
            | (LuaValue::Map(_), LuaValue::String(_))
            | (LuaValue::Array(_), LuaValue::String(_)) => Ordering::Less,
            (LuaValue::Boolean(b1), LuaValue::Boolean(b2)) => b1.cmp(b2),
            (LuaValue::Boolean(_), LuaValue::Map(_))
            | (LuaValue::Boolean(_), LuaValue::Array(_)) => Ordering::Greater,
            (LuaValue::Map(_), LuaValue::Boolean(_))
            | (LuaValue::Array(_), LuaValue::Boolean(_)) => Ordering::Less,
            (LuaValue::Map(m1), LuaValue::Map(m2)) => {
                let p1 = (m1 as *const Map<LuaMapKey, LuaValue>).addr();
                let p2 = (m2 as *const Map<LuaMapKey, LuaValue>).addr();
                p1.cmp(&p2)
            }
            (LuaValue::Map(_), LuaValue::Array(_)) => Ordering::Greater,
            (LuaValue::Array(_), LuaValue::Map(_)) => Ordering::Less,
            (LuaValue::Array(v1), LuaValue::Array(v2)) => {
                let p1 = (v1 as *const Vec<LuaValue>).addr();
                let p2 = (v2 as *const Vec<LuaValue>).addr();
                p1.cmp(&p2)
            }
            (LuaValue::Null, LuaValue::Null) => Ordering::Equal,
            (LuaValue::Null, _) => Ordering::Less,
            (_, LuaValue::Null) => Ordering::Greater,
        }
    }
}
impl PartialEq for LuaValue {
    fn eq(&self, other: &LuaValue) -> bool {
        match (self, other) {
            (LuaValue::Map(m1), LuaValue::Map(m2)) => {
                let p1 = (m1 as *const Map<LuaMapKey, LuaValue>).addr();
                let p2 = (m2 as *const Map<LuaMapKey, LuaValue>).addr();
                p1.eq(&p2)
            }
            (LuaValue::Array(v1), LuaValue::Array(v2)) => {
                let p1 = (v1 as *const Vec<LuaValue>).addr();
                let p2 = (v2 as *const Vec<LuaValue>).addr();
                p1.eq(&p2)
            }
            (LuaValue::String(s1), LuaValue::String(s2)) => s1.eq(s2),
            (LuaValue::Number(n1), LuaValue::Number(n2)) => n1.eq(n2),
            (LuaValue::Boolean(b1), LuaValue::Boolean(b2)) => b1.eq(b2),
            (LuaValue::Null, LuaValue::Null) => true,
            _ => false,
        }
    }
}
impl Eq for LuaValue {}

impl Hash for LuaMapKey {
    #[inline(always)]
    fn hash<H: Hasher>(&self, state: &mut H) {
        self.0.hash(state)
    }
}
impl PartialOrd for LuaMapKey {
    #[inline(always)]
    fn partial_cmp(&self, other: &LuaMapKey) -> Option<Ordering> {
        Some(self.0.cmp(&other.0))
    }
}
impl Ord for LuaMapKey {
    #[inline(always)]
    fn cmp(&self, other: &LuaMapKey) -> Ordering {
        self.0.cmp(&other.0)
    }
}
impl PartialEq for LuaMapKey {
    #[inline(always)]
    fn eq(&self, other: &LuaMapKey) -> bool {
        self.0.eq(&other.0)
    }
}
impl Eq for LuaMapKey {}

#[cfg(feature = "serde")]
use std::borrow::Cow;
impl LuaMapKey {
    #[cfg(feature = "serde")]
    fn to_string(&self) -> Cow<'_, str> {
        match self.0 {
            LuaValue::String(ref v) => Cow::from(v),
            LuaValue::Number(v) => Cow::from(v.to_string()),
            LuaValue::Boolean(v) => Cow::from(v.to_string()),
            LuaValue::Map(ref m) => Cow::from(format!("map at {m:p}")),
            LuaValue::Array(ref m) => Cow::from(format!("array at {m:p}")),
            LuaValue::Null => unsafe { core::hint::unreachable_unchecked() },
        }
    }
}

use core::fmt::{self, Debug};
impl Debug for LuaMapKey {
    #[inline(always)]
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        Debug::fmt(&self.0, f)
    }
}

#[cfg(feature = "arbitrary")]
impl<'a> Arbitrary<'a> for LuaMapKey {
    #[inline(always)]
    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
        let key = LuaValue::arbitrary(u)?;
        LuaMapKey::try_from(key).map_err(|_| arbitrary::Error::IncorrectFormat)
    }

    #[inline(always)]
    fn arbitrary_take_rest(u: arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
        let key = LuaValue::arbitrary_take_rest(u)?;
        LuaMapKey::try_from(key).map_err(|_| arbitrary::Error::IncorrectFormat)
    }

    #[inline(always)]
    fn size_hint(depth: usize) -> (usize, Option<usize>) {
        LuaValue::size_hint(depth)
    }

    #[inline(always)]
    fn try_size_hint(
        depth: usize,
    ) -> arbitrary::Result<(usize, Option<usize>), arbitrary::MaxRecursionReached> {
        LuaValue::try_size_hint(depth)
    }
}

#[cfg(feature = "serde")]
impl Serialize for LuaValue {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        use serde::ser::{SerializeMap, SerializeSeq};

        match self {
            LuaValue::String(s) => serializer.serialize_str(s),
            LuaValue::Number(n) => serializer.serialize_f64(*n),
            LuaValue::Boolean(b) => serializer.serialize_bool(*b),
            LuaValue::Null => serializer.serialize_none(),
            LuaValue::Map(m) => {
                let mut map = serializer.serialize_map(Some(m.len()))?;
                for (k, v) in m {
                    map.serialize_entry(&LuaMapKey::to_string(k), v)?;
                }
                map.end()
            }
            LuaValue::Array(v) => {
                let mut seq = serializer.serialize_seq(Some(v.len()))?;
                for el in v {
                    seq.serialize_element(el)?;
                }
                seq.end()
            }
        }
    }
}

#[cfg(feature = "serde")]
impl<'de> Deserialize<'de> for LuaValue {
    fn deserialize<D>(deserializer: D) -> Result<LuaValue, D::Error>
    where
        D: Deserializer<'de>,
    {
        struct LuaValueVisitor;

        impl<'de> Visitor<'de> for LuaValueVisitor {
            type Value = LuaValue;

            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
                formatter.write_str("a Lua value")
            }

            fn visit_none<E>(self) -> Result<LuaValue, E> {
                Ok(LuaValue::Null)
            }

            fn visit_unit<E>(self) -> Result<LuaValue, E> {
                Ok(LuaValue::Null)
            }

            fn visit_bool<E>(self, value: bool) -> Result<LuaValue, E> {
                Ok(LuaValue::Boolean(value))
            }

            fn visit_i64<E>(self, value: i64) -> Result<LuaValue, E>
            where
                E: de::Error,
            {
                let value_f64 = value as f64;
                if value_f64 as i64 == value {
                    Ok(LuaValue::Number(value_f64))
                } else {
                    Err(de::Error::custom("can't represent as f64"))
                }
            }

            fn visit_u64<E>(self, value: u64) -> Result<LuaValue, E>
            where
                E: de::Error,
            {
                let value_f64 = value as f64;
                if value_f64 as u64 == value {
                    Ok(LuaValue::Number(value_f64))
                } else {
                    Err(de::Error::custom("can't represent as f64"))
                }
            }

            fn visit_f64<E>(self, value: f64) -> Result<LuaValue, E> {
                Ok(LuaValue::Number(value))
            }

            fn visit_str<E>(self, value: &str) -> Result<LuaValue, E>
            where
                E: de::Error,
            {
                self.visit_string(String::from(value))
            }

            fn visit_string<E>(self, value: String) -> Result<LuaValue, E> {
                Ok(LuaValue::String(value))
            }

            fn visit_seq<V>(self, mut seq: V) -> Result<LuaValue, V::Error>
            where
                V: SeqAccess<'de>,
            {
                let mut result = Vec::with_capacity(seq.size_hint().unwrap_or(16));

                while let Some(element) = seq.next_element()? {
                    result.push(element);
                }

                Ok(LuaValue::Array(result))
            }

            fn visit_map<V>(self, mut map: V) -> Result<LuaValue, V::Error>
            where
                V: MapAccess<'de>,
            {
                #[cfg(any(feature = "indexmap", feature = "fnv"))]
                let mut result = Map::with_capacity(map.size_hint().unwrap_or(16));
                #[cfg(not(any(feature = "indexmap", feature = "fnv")))]
                let mut result = Map::new();

                while let Some(key) = map.next_key()? {
                    let key = LuaMapKey::try_from(match key {
                        LuaValue::String(s) => match s.parse::<i32>() {
                            Ok(n) => LuaValue::Number(n as f64),
                            Err(_) => LuaValue::String(s),
                        },
                        v => v,
                    })
                    .map_err(de::Error::custom)?;

                    let value = map.next_value()?;

                    result.insert(key, value);
                }

                Ok(LuaValue::Map(result))
            }
        }

        deserializer.deserialize_any(LuaValueVisitor)
    }
}