feat: soa_attr for Vec's field

Author: CurryPseudo

soa-derive-internal/src/input.rs

@@ -12,6 +12,8 @@ pub struct Input {
     pub name: Ident,
     /// The list of fields in the struct
     pub fields: Vec<Field>,
+    /// Additional attributes requested with `#[soa_attr(...)]` on fields
+    pub field_attrs: Vec<ExtraAttributes>,
     /// The struct overall visibility
     pub visibility: Visibility,
     /// Additional attributes requested with `#[soa_attr(...)]` or
@@ -145,8 +147,23 @@ fn create_derive_meta(path: Path) -> Meta {
 
 impl Input {
     pub fn new(input: DeriveInput) -> Input {
-        let fields = match input.data {
-            Data::Struct(s) => s.fields.iter().cloned().collect::<Vec<_>>(),
+        let mut fields = Vec::new();
+        let mut field_attrs = Vec::new();
+        match input.data {
+            Data::Struct(s) => {
+                for field in s.fields.iter() {
+                    let mut extra_attrs = ExtraAttributes::new();
+                    fields.push(field.clone());
+                    for attr in &field.attrs {
+                        if let Ok(meta) = attr.parse_meta() {
+                            if meta.path().is_ident("soa_attr") {
+                                extra_attrs.parse(&meta);
+                            }
+                        }
+                    }
+                    field_attrs.push(extra_attrs);
+                }
+            }
             _ => panic!("#[derive(StructOfArray)] only supports struct"),
         };
 
@@ -201,6 +218,7 @@ impl Input {
             visibility: input.vis,
             attrs: extra_attrs,
             derive_clone,
+            field_attrs,
         }
     }
 

soa-derive-internal/src/vec.rs

@@ -35,6 +35,9 @@ pub fn derive(input: &Input) -> TokenStream {
     let fields_types = &input.fields.iter()
                                     .map(|field| &field.ty)
                                     .collect::<Vec<_>>();
+    
+    let field_attrs = input.field_attrs.iter()
+        .map(|attr| &attr.vec).collect::<Vec<_>>();
 
     let mut generated = quote! {
         /// An analog to `
@@ -45,6 +48,7 @@ pub fn derive(input: &Input) -> TokenStream {
         #visibility struct #vec_name {
             #(
                 #[doc = #fields_doc]
+                #(#[#field_attrs])*
                 pub #fields_names: Vec<#fields_types>,
             )*
         }

tests/soa_attr.rs

@@ -1,3 +1,4 @@
+use serde::{Serialize, Deserialize};
 use soa_derive::StructOfArray;
 
 #[derive(Debug, Clone, PartialEq, StructOfArray)]
@@ -25,3 +26,30 @@ fn eq_test() {
     };
     assert_eq!(particles0, particles1);
 }
+
+#[derive(StructOfArray)]
+#[soa_derive(PartialEq, Debug, Serialize, Deserialize)]
+pub struct Point {
+    pub x: f32,
+    pub y: f32,
+    #[soa_attr(Vec, serde(skip))]
+    pub meta: bool
+}
+
+#[test]
+fn serde_skip_test() -> Result<(), serde_json::Error> {
+    let mut soa = PointVec::new();
+    soa.push(Point { x: 1.0, y: 2.0, meta: true });
+    soa.push(Point { x: 3.0, y: 4.0, meta: false });
+
+
+    let json = serde_json::to_string(&soa)?;
+    assert_eq!(json, r#"{"x":[1.0,3.0],"y":[2.0,4.0]}"#);
+    let soa2: PointVec = serde_json::from_str(&json)?;
+    assert_eq!(&soa2, &PointVec {
+        x: vec![1.0, 3.0],
+        y: vec![2.0, 4.0],
+        meta: vec![]
+    });
+    Ok(())
+}