derive macros for entity parsing

Cargo.toml

@@ -19,6 +19,7 @@ lzma-rs = "0.2.0"
 binrw = "0.8.0"
 static_assertions = "1.1.0"
 num_enum = "0.5.6"
+vbsp-derive = { path = "derive", version = "*" }
 
 [dev-dependencies]
 obj = "0.10"

derive/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+name = "vbsp-derive"
+version = "0.1.0"
+authors = ["Robin Appelman <robin@icewind.nl>"]
+homepage = "https://github.com/icewind1991/vbsp"
+repository = "https://github.com/icewind1991/vbsp"
+description = "Derive macros used by vbsp."
+license = "MIT"
+edition = "2021"
+
+[lib]
+proc-macro = true
+
+[dependencies]
+syn = "1.0.82"
+quote = "1.0.10"
+proc-macro2 = "1.0.33"
+syn_util = "0.4.2"
+
+[features]
+__vbsp_as_self = []

derive/src/entity.rs

@@ -0,0 +1,190 @@
+use proc_macro2::{Ident, TokenStream};
+use quote::{quote, ToTokens, TokenStreamExt};
+use syn::{
+    Data, DataEnum, DataStruct, DeriveInput, Field, GenericParam, Path, PathArguments, PathSegment,
+    Type, TypePath, Variant,
+};
+use syn_util::{contains_attribute, get_attribute_value};
+
+type Result<T, E = String> = std::result::Result<T, E>;
+
+pub fn derive_entity(input: DeriveInput) -> Result<proc_macro2::TokenStream> {
+    if input.generics.lifetimes().count() > 1 {
+        return Err("Can't derive Entity on structs or entities with more than 1 lifetime".into());
+    }
+    let source_lifetime = input
+        .generics
+        .params
+        .iter()
+        .find(|param| matches!(param, GenericParam::Lifetime(_)));
+
+    match &input.data {
+        Data::Struct(data) => derive_entity_struct(&input, data, source_lifetime),
+        Data::Enum(data) => derive_entity_enum(&input, data, source_lifetime),
+        _ => Err("Can only derive Entity for structs and enums".into()),
+    }
+}
+
+fn derive_entity_enum(
+    input: &DeriveInput,
+    data: &DataEnum,
+    source_lifetime: Option<&GenericParam>,
+) -> Result<proc_macro2::TokenStream> {
+    let variants = data
+        .variants
+        .iter()
+        .filter(|variant| !contains_attribute(&variant.attrs, &["entity", "default"]))
+        .map(EntityVariant::try_from)
+        .collect::<Result<Vec<_>, _>>()?;
+
+    let default = &data
+        .variants
+        .iter()
+        .find(|variant| contains_attribute(&variant.attrs, &["entity", "default"]))
+        .ok_or("Enum must have one variant with `#[entity(default)]` set")?
+        .ident;
+
+    let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
+    let name = &input.ident;
+    let lifetime_or_default = LifetimeOrAnonymous(source_lifetime);
+
+    Ok(quote! {
+        impl #impl_generics TryFrom<crate::RawEntity<#lifetime_or_default>> for #name #ty_generics #where_clause {
+            type Error = crate::error::EntityParseError;
+
+            fn try_from(raw: crate::RawEntity<#source_lifetime>) -> Result<Self, Self::Error> {
+                let class = raw.prop("classname")?;
+                Ok(match class {
+                    #(#variants)*
+                    _ => Self::#default(raw),
+                })
+            }
+        }
+    })
+}
+
+fn derive_entity_struct(
+    input: &DeriveInput,
+    data: &DataStruct,
+    source_lifetime: Option<&GenericParam>,
+) -> Result<proc_macro2::TokenStream> {
+    let fields = data
+        .fields
+        .iter()
+        .map(EntityField::try_from)
+        .collect::<Result<Vec<_>, _>>()?;
+
+    let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
+    let name = &input.ident;
+    let lifetime_or_default = LifetimeOrAnonymous(source_lifetime);
+
+    Ok(quote! {
+        impl #impl_generics TryFrom<crate::RawEntity<#lifetime_or_default>> for #name #ty_generics #where_clause {
+            type Error = crate::error::EntityParseError;
+
+            fn try_from(raw: crate::RawEntity<#source_lifetime>) -> Result<Self, Self::Error> {
+                Ok(#name {
+                    #(#fields)*
+                })
+            }
+        }
+    })
+}
+
+struct LifetimeOrAnonymous<'a>(Option<&'a GenericParam>);
+
+impl ToTokens for LifetimeOrAnonymous<'_> {
+    fn to_tokens(&self, stream: &mut TokenStream) {
+        match &self.0 {
+            Some(params) => params.to_tokens(stream),
+            None => stream.append_all(quote! {'_}),
+        }
+    }
+}
+
+struct EntityField<'a> {
+    field: &'a Ident,
+    name: String,
+    default: bool,
+}
+
+impl<'a> TryFrom<&'a Field> for EntityField<'a> {
+    type Error = String;
+
+    fn try_from(field: &'a Field) -> std::result::Result<Self, Self::Error> {
+        let ident = &field
+            .ident
+            .as_ref()
+            .ok_or_else(|| format!("Can't derive Entity on structs with unnamed fields"))?;
+        let name = get_attribute_value(&field.attrs, &["entity", "name"])
+            .unwrap_or_else(|| ident.to_string());
+        let default = contains_attribute(&field.attrs, &["entity", "default"]);
+        Ok(EntityField {
+            field: ident,
+            name,
+            default,
+        })
+    }
+}
+
+impl ToTokens for EntityField<'_> {
+    fn to_tokens(&self, stream: &mut TokenStream) {
+        let EntityField { field, name, .. } = &self;
+        let tokens = if self.default {
+            quote! {#field: raw.prop_parse(#name).unwrap_or_default(),}
+        } else {
+            quote! {#field: raw.prop_parse(#name)?,}
+        };
+        stream.append_all(tokens);
+    }
+}
+
+struct EntityVariant<'a> {
+    name: String,
+    variant: &'a Ident,
+    ty: &'a Path,
+}
+
+impl<'a> TryFrom<&'a Variant> for EntityVariant<'a> {
+    type Error = String;
+
+    fn try_from(value: &'a Variant) -> std::result::Result<Self, Self::Error> {
+        let name = get_attribute_value(&value.attrs, &["entity", "name"]).ok_or_else(|| {
+            "All variants must have the `#[entity(name)]` or `#[entity(default)]` attribute set"
+                .to_string()
+        })?;
+        if value.fields.len() != 1 {
+            return Err("All enum variants must have exactly one field".into());
+        }
+        let field = value.fields.iter().next().unwrap();
+        let path = match &field.ty {
+            Type::Path(TypePath { path, .. }) => path,
+            _ => return Err("Varients can only contain plain types".into()),
+        };
+        Ok(EntityVariant {
+            name,
+            variant: &value.ident,
+            ty: &path,
+        })
+    }
+}
+
+impl ToTokens for EntityVariant<'_> {
+    fn to_tokens(&self, stream: &mut TokenStream) {
+        let EntityVariant { name, variant, ty } = &self;
+
+        // strip lifetime params
+        let ty = Path {
+            leading_colon: ty.leading_colon.clone(),
+            segments: ty
+                .segments
+                .iter()
+                .map(|segment| PathSegment {
+                    ident: segment.ident.clone(),
+                    arguments: PathArguments::None,
+                })
+                .collect(),
+        };
+        stream.append_all(quote! {#name => Self::#variant(#ty::try_from(raw)?),});
+    }
+}

derive/src/lib.rs

@@ -0,0 +1,19 @@
+use quote::quote;
+use syn::{parse_macro_input, DeriveInput};
+
+mod entity;
+
+#[proc_macro_derive(Entity, attributes(entity))]
+pub fn derive_entity(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    derive_wrapper(input, entity::derive_entity)
+}
+
+fn derive_wrapper<F: Fn(DeriveInput) -> Result<proc_macro2::TokenStream, String>>(
+    input: proc_macro::TokenStream,
+    derive: F,
+) -> proc_macro::TokenStream {
+    match derive(parse_macro_input!(input as DeriveInput)) {
+        Ok(tokens) => tokens.into(),
+        Err(e) => quote!(compile_error!(#e)).into(),
+    }
+}

derive/tests/expand.rs

@@ -0,0 +1,27 @@
+use vbsp::RawEntity;
+use vbsp_derive::Entity;
+
+#[derive(Entity)]
+pub struct SpotLight {
+    pub angles: [f32; 3],
+    #[entity(name = "render_color")]
+    pub color: [u8; 3],
+    pub cone: u8,
+    #[entity(default)]
+    pub optional: bool,
+}
+
+#[derive(Entity)]
+pub struct Lifetime<'a> {
+    pub model: &'a str,
+}
+
+#[derive(Entity)]
+pub enum Entity<'a> {
+    // #[entity(name = "spot")]
+    // SpotLight(SpotLight),
+    #[entity(name = "bar")]
+    Foo(Lifetime<'a>),
+    #[entity(default)]
+    Unknown(RawEntity<'a>),
+}

src/data/entity.rs

@@ -3,6 +3,7 @@ use crate::Vector;
 use std::fmt;
 use std::fmt::Debug;
 use std::str::FromStr;
+use vbsp_derive::Entity;
 
 #[derive(Clone)]
 pub struct Entities {
@@ -101,260 +102,227 @@ impl<'a> RawEntity<'a> {
             .ok_or(EntityParseError::NoSuchProperty(key))
     }
 
-    fn prop_parse<T: FromStr>(&self, key: &'static str) -> Result<T, EntityParseError>
+    fn prop_parse<T: EntityProp<'a>>(&self, key: &'static str) -> Result<T, EntityParseError> {
+        T::parse(self.prop(key)?)
+    }
+
+    pub fn parse(&self) -> Result<Entity<'a>, EntityParseError> {
+        self.clone().try_into()
+    }
+}
+
+trait EntityProp<'a>: Sized {
+    fn parse(raw: &'a str) -> Result<Self, EntityParseError>;
+}
+
+trait FromStrProp: FromStr {}
+
+impl FromStrProp for u8 {}
+impl FromStrProp for f32 {}
+impl FromStrProp for u32 {}
+impl FromStrProp for Vector {}
+
+impl<T: FromStrProp> EntityProp<'_> for T
 where
     EntityParseError: From<<T as FromStr>::Err>,
 {
-        Ok(self.prop(key)?.parse()?)
+    fn parse(raw: &'_ str) -> Result<Self, EntityParseError> {
+        Ok(raw.parse()?)
+    }
 }
 
-    fn prop_parse_space_seperated<T: FromStr + Default, const N: usize>(
-        &self,
-        key: &'static str,
-    ) -> Result<[T; N], EntityParseError>
+impl<T: FromStrProp, const N: usize> EntityProp<'_> for [T; N]
 where
     EntityParseError: From<<T as FromStr>::Err>,
     [T; N]: Default,
 {
-        let prop = self.prop(key)?;
-        let mut values = prop.split(" ").map(T::from_str);
+    fn parse(raw: &'_ str) -> Result<Self, EntityParseError> {
+        let mut values = raw.split(" ").map(T::from_str);
         let mut result = <[T; N]>::default();
         for i in 0..N {
             result[i] = values.next().ok_or(EntityParseError::ElementCount)??;
         }
         Ok(result)
     }
-
-    pub fn parse(&self) -> Result<Entity<'a>, EntityParseError> {
-        let class = self.prop("classname")?;
-        match class {
-            "prop_dynamic" => Ok(Entity::PropDynamic(PropDynamic {
-                angles: self.prop_parse_space_seperated("angles")?,
-                disable_receive_shadows: self
-                    .prop_parse::<u8>("disablereceiveshadows")
-                    .unwrap_or_default()
-                    > 0,
-                disable_shadows: self
-                    .prop_parse::<u8>("disablereceiveshadows")
-                    .unwrap_or_default()
-                    > 0,
-                scale: self.prop_parse("modelscale")?,
-                model: self.prop("model")?,
-                origin: self.prop_parse("angles")?,
-                color: self.prop_parse_space_seperated("rendercolor")?,
-                name: self.prop("targetname").ok(),
-                parent: self.prop("parentname").ok(),
-            })),
-            "prop_physics_multiplayer" => Ok(Entity::PropPhysics(PropDynamic {
-                angles: self.prop_parse_space_seperated("angles")?,
-                disable_receive_shadows: self
-                    .prop_parse::<u8>("disablereceiveshadows")
-                    .unwrap_or_default()
-                    > 0,
-                disable_shadows: self
-                    .prop_parse::<u8>("disablereceiveshadows")
-                    .unwrap_or_default()
-                    > 0,
-                scale: self.prop_parse("modelscale")?,
-                model: self.prop("model")?,
-                origin: self.prop_parse("angles")?,
-                color: self.prop_parse_space_seperated("rendercolor")?,
-                name: self.prop("targetname").ok(),
-                parent: self.prop("parentname").ok(),
-            })),
-            "light_spot" => Ok(Entity::SpotLight(SpotLight {
-                origin: self.prop_parse("origin")?,
-                angles: self.prop_parse_space_seperated("angles")?,
-                color: self.prop_parse_space_seperated("_light")?,
-                cone: self.prop_parse("_cone")?,
-            })),
-            "point_spotlight" => Ok(Entity::SpotLight(SpotLight {
-                origin: self.prop_parse("origin")?,
-                angles: self.prop_parse_space_seperated("angles")?,
-                color: self.prop_parse_space_seperated("rendercolor")?,
-                cone: self.prop_parse("spotlightwidth")?,
-            })),
-            "env_sprite" => Ok(Entity::EnvSprite(EnvSprite {
-                origin: self.prop_parse("origin")?,
-                scale: self.prop_parse("scale")?,
-                model: self.prop("model")?,
-                color: self.prop_parse_space_seperated("rendercolor")?,
-            })),
-            "info_player_teamspawn" => Ok(Entity::Spawn(Spawn {
-                origin: self.prop_parse("origin")?,
-                angles: self.prop_parse_space_seperated("angles")?,
-                target: self.prop("targetname").ok(),
-                control_point: self.prop("controlpoint").ok(),
-                start_disabled: self.prop_parse::<u8>("StartDisabled").unwrap_or_default() > 0,
-                team: self.prop_parse("TeamNum")?,
-            })),
-            "func_door" => Ok(Entity::Door(Door {
-                origin: self.prop_parse("origin")?,
-                target: self.prop("targetname")?,
-                speed: self.prop_parse("speed")?,
-                force_closed: self.prop_parse::<u8>("forceclosed").unwrap_or_default() > 0,
-                move_direction: self.prop_parse("movedir")?,
-                model: self.prop("model")?,
-            })),
-            "item_ammopack_small" => Ok(Entity::AmmoPack(AmmoPack {
-                origin: self.prop_parse("origin")?,
-                ty: PackType::Small,
-            })),
-            "item_ammopack_medium" => Ok(Entity::AmmoPack(AmmoPack {
-                origin: self.prop_parse("origin")?,
-                ty: PackType::Medium,
-            })),
-            "item_ammopack_large" => Ok(Entity::AmmoPack(AmmoPack {
-                origin: self.prop_parse("origin")?,
-                ty: PackType::Large,
-            })),
-            "item_healthkit_small" => Ok(Entity::HealthPack(HealthPack {
-                origin: self.prop_parse("origin")?,
-                ty: PackType::Small,
-            })),
-            "item_healthkit_medium" => Ok(Entity::HealthPack(HealthPack {
-                origin: self.prop_parse("origin")?,
-                ty: PackType::Medium,
-            })),
-            "item_healthkit_large" => Ok(Entity::HealthPack(HealthPack {
-                origin: self.prop_parse("origin")?,
-                ty: PackType::Large,
-            })),
-            "worldspawn" => Ok(Entity::WorldSpawn(WorldSpawn {
-                min: self.prop_parse("world_mins")?,
-                max: self.prop_parse("world_maxs")?,
-                detail_vbsp: self.prop("detailvbsp")?,
-                detail_material: self.prop("detailmaterial")?,
-                comment: self.prop("comment").ok(),
-                skybox: self.prop("skyname")?,
-                version: self.prop_parse("mapversion")?,
-            })),
-            "info_observer_point" => Ok(Entity::ObserverPoint(ObserverPoint {
-                start_disabled: self.prop_parse::<u8>("StartDisabled").unwrap_or_default() > 0,
-                angles: self.prop_parse_space_seperated("angles")?,
-                origin: self.prop_parse("origin")?,
-                target: self.prop("targetname").ok(),
-                parent: self.prop("parentname").ok(),
-            })),
-            "func_brush" => Ok(Entity::Brush(BrushEntity {
-                model: self.prop("model")?,
-                start_disabled: self.prop_parse::<u8>("StartDisabled").unwrap_or_default() > 0,
-                origin: self.prop_parse("origin")?,
-                color: self.prop_parse_space_seperated("rendercolor")?,
-            })),
-            _ => Ok(Entity::Unknown(self.clone())),
 }
+
+impl<'a> EntityProp<'a> for &'a str {
+    fn parse(raw: &'a str) -> Result<Self, EntityParseError> {
+        Ok(raw)
     }
 }
 
-#[derive(Debug, Clone)]
+impl EntityProp<'_> for bool {
+    fn parse(raw: &'_ str) -> Result<Self, EntityParseError> {
+        Ok(raw != "0")
+    }
+}
+
+impl<'a, T: EntityProp<'a>> EntityProp<'a> for Option<T> {
+    fn parse(raw: &'a str) -> Result<Self, EntityParseError> {
+        Ok(Some(T::parse(raw)?))
+    }
+}
+
+#[derive(Debug, Clone, Entity)]
 pub enum Entity<'a> {
+    #[entity(name = "point_spotlight")]
     SpotLight(SpotLight),
+    #[entity(name = "light_spot")]
+    LightSpot(LightSpot),
+    #[entity(name = "prop_dynamic")]
     PropDynamic(PropDynamic<'a>),
+    #[entity(name = "prop_physics_multiplayer")]
     PropPhysics(PropDynamic<'a>),
+    #[entity(name = "env_sprite")]
     EnvSprite(EnvSprite<'a>),
+    #[entity(name = "info_player_teamspawn")]
     Spawn(Spawn<'a>),
+    #[entity(name = "func_door")]
     Door(Door<'a>),
-    AmmoPack(AmmoPack),
-    HealthPack(HealthPack),
+    #[entity(name = "worldspawn")]
     WorldSpawn(WorldSpawn<'a>),
+    #[entity(name = "info_observer_point")]
     ObserverPoint(ObserverPoint<'a>),
+    #[entity(name = "func_brush")]
     Brush(BrushEntity<'a>),
+    #[entity(name = "item_ammopack_small")]
+    AmmoPackSmall(AmmoPack),
+    #[entity(name = "item_ammopack_medium")]
+    AmmoPackMedium(AmmoPack),
+    #[entity(name = "item_ammopack_large")]
+    HealthPackLarge(HealthPack),
+    #[entity(name = "item_healthkit_small")]
+    HealthPackSmall(HealthPack),
+    #[entity(name = "item_healthkit_medium")]
+    HealthPackMedium(HealthPack),
+    #[entity(name = "item_healthkit_large")]
+    AmmoPackLarge(AmmoPack),
+    #[entity(default)]
     Unknown(RawEntity<'a>),
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Entity)]
 pub struct SpotLight {
     pub origin: Vector,
     pub angles: [f32; 3],
+    #[entity(name = "rendercolor")]
     pub color: [u8; 3],
+    #[entity(name = "spotlightwidth")]
     pub cone: u8,
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Entity)]
+pub struct LightSpot {
+    pub origin: Vector,
+    pub angles: [f32; 3],
+    #[entity(name = "_light")]
+    pub color: [u8; 3],
+    #[entity(name = "_cone")]
+    pub cone: u8,
+}
+
+#[derive(Debug, Clone, Entity)]
 pub struct PropDynamic<'a> {
     pub angles: [f32; 3],
+    #[entity(name = "disablereceiveshadows", default)]
     pub disable_receive_shadows: bool,
+    #[entity(name = "disableshadows", default)]
     pub disable_shadows: bool,
+    #[entity(name = "modelscale")]
     pub scale: f32,
     pub model: &'a str,
     pub origin: Vector,
+    #[entity(name = "rendercolor")]
     pub color: [u8; 3],
+    #[entity(name = "targetname", default)]
     pub name: Option<&'a str>,
+    #[entity(name = "parentname", default)]
     pub parent: Option<&'a str>,
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Entity)]
 pub struct EnvSprite<'a> {
     pub origin: Vector,
     pub scale: f32,
     pub model: &'a str,
+    #[entity(name = "rendercolor")]
     pub color: [u8; 3],
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Entity)]
 pub struct Spawn<'a> {
     pub origin: Vector,
     pub angles: [f32; 3],
+    #[entity(name = "targetname", default)]
     pub target: Option<&'a str>,
+    #[entity(name = "controlpoint", default)]
     pub control_point: Option<&'a str>,
+    #[entity(name = "StartDisabled", default)]
     pub start_disabled: bool,
+    #[entity(name = "TeamNum")]
     pub team: u8,
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Entity)]
 pub struct Door<'a> {
     pub origin: Vector,
+    #[entity(name = "targetname", default)]
     pub target: &'a str,
     pub speed: f32,
+    #[entity(name = "forceclosed", default)]
     pub force_closed: bool,
+    #[entity(name = "movedir")]
     pub move_direction: Vector,
     pub model: &'a str,
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Entity)]
 pub struct AmmoPack {
     pub origin: Vector,
-    pub ty: PackType,
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Entity)]
 pub struct HealthPack {
     pub origin: Vector,
-    pub ty: PackType,
 }
 
-#[derive(Debug, Clone)]
-pub enum PackType {
-    Small,
-    Medium,
-    Large,
-}
-
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Entity)]
 pub struct WorldSpawn<'a> {
+    #[entity(name = "world_mins")]
     pub min: Vector,
+    #[entity(name = "world_mins")]
     pub max: Vector,
+    #[entity(name = "detailvbsp")]
     pub detail_vbsp: &'a str,
+    #[entity(name = "detailmaterial")]
     pub detail_material: &'a str,
+    #[entity(default)]
     pub comment: Option<&'a str>,
+    #[entity(name = "skyname")]
     pub skybox: &'a str,
+    #[entity(name = "mapversion")]
     pub version: u32,
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Entity)]
 pub struct ObserverPoint<'a> {
+    #[entity(name = "StartDisabled", default)]
     pub start_disabled: bool,
     pub angles: [f32; 3],
     pub origin: Vector,
+    #[entity(name = "targetname", default)]
     pub target: Option<&'a str>,
+    #[entity(name = "parentname", default)]
     pub parent: Option<&'a str>,
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Entity)]
 pub struct BrushEntity<'a> {
     pub model: &'a str,
     pub origin: Vector,
+    #[entity(name = "StartDisabled", default)]
     pub start_disabled: bool,
+    #[entity(name = "rendercolor")]
     pub color: [f32; 3],
 }

src/lib.rs

@@ -1,13 +1,13 @@
 mod bspfile;
 pub mod data;
-mod error;
+pub mod error;
 mod handle;
 mod reader;
 
 use crate::bspfile::LumpType;
 pub use crate::data::TextureFlags;
 pub use crate::data::Vector;
-use crate::data::*;
+pub use crate::data::*;
 use crate::error::ValidationError;
 pub use crate::handle::Handle;
 use binrw::io::Cursor;