editoast: add the possibility of #[model(uom_unit="...")]

Signed-off-by: Tristram Gräbener <[email protected]>

Author: Tristramg

editoast/editoast_derive/src/lib.rs

@@ -217,6 +217,7 @@ pub fn search_config_store(input: proc_macro::TokenStream) -> proc_macro::TokenS
 /// * `#[model(to_string)]`: calls `to_string()` before writing the field to the database and calls `String::from` after reading (diesel column type: String)
 /// * `#[model(to_enum)]`: is converted as `u8` before writing the field to the database and calls `FromRepr::from_repr` after reading (diesel column type: TinyInt)
 /// * `#[model(remote = "T")]`: calls `Into::<T>::into` before writing the field to the database and calls `T::from` after reading (diesel column type: T)
+/// * `#[model(uom_unit = "T")]`: the field is an uom quantity and stored in the database in the unit `T`, e.g. `"uom::si::length::meter"`
 /// * `#[model(geo)]` **TODO**: TBD
 ///
 /// #### A note on identifiers

editoast/editoast_derive/src/model/args.rs

@@ -79,6 +79,8 @@ pub(super) struct ModelFieldArgs {
     pub(super) to_enum: bool,
     #[darling(default)]
     pub(super) remote: Option<syn::Type>,
+    #[darling(default)]
+    pub(super) uom_unit: Option<syn::Type>,
 }
 
 impl GeneratedTypeArgs {

editoast/editoast_derive/src/model/config.rs

@@ -45,6 +45,7 @@ pub(crate) enum FieldTransformation {
     Geo,
     ToString,
     ToEnum(syn::Type),
+    UomUnit(syn::Type),
 }
 
 #[derive(Debug, PartialEq)]
@@ -132,12 +133,14 @@ impl ModelField {
             Some(FieldTransformation::ToEnum(_)) => {
                 parse_quote! { #expr as i16 }
             }
+            Some(FieldTransformation::UomUnit(ref unit)) => parse_quote! { #expr.get::<#unit>() },
             None => parse_quote! { #expr },
         }
     }
 
     #[allow(clippy::wrong_self_convention)]
     pub(crate) fn from_transformed(&self, expr: syn::Expr) -> syn::Expr {
+        let ty = &self.ty;
         match self.transform {
             Some(FieldTransformation::Remote(_)) => parse_quote! { #expr.into() },
             Some(FieldTransformation::Json) => parse_quote! { #expr.0 },
@@ -146,6 +149,9 @@ impl ModelField {
             Some(FieldTransformation::ToEnum(ref ty)) => {
                 parse_quote! { #ty::from_repr(#expr as usize).expect("Invalid variant repr") }
             }
+            Some(FieldTransformation::UomUnit(ref unit)) => {
+                parse_quote! { #ty::new::<#unit>(#expr) }
+            }
             None => parse_quote! { #expr },
         }
     }
@@ -158,6 +164,7 @@ impl ModelField {
             Some(FieldTransformation::Geo) => unimplemented!("to be designed"),
             Some(FieldTransformation::ToString) => parse_quote! { String },
             Some(FieldTransformation::ToEnum(_)) => parse_quote! { i16 },
+            Some(FieldTransformation::UomUnit(_)) => parse_quote! { f64 },
             None => ty.clone(),
         }
     }

editoast/editoast_derive/src/model/parsing.rs

@@ -165,6 +165,7 @@ impl ModelField {
             value.geo,
             value.to_string,
             to_enum,
+            value.uom_unit,
         )
         .map_err(|e| e.with_span(&ident))?;
         Ok(Self {
@@ -188,16 +189,18 @@ impl FieldTransformation {
         geo: bool,
         to_string: bool,
         to_enum: Option<syn::Type>,
+        uom_unit: Option<syn::Type>,
     ) -> darling::Result<Option<Self>> {
-        match (remote, json, geo, to_string, to_enum) {
-            (Some(ty), false, false, false, None) => Ok(Some(Self::Remote(ty))),
-            (None, true, false, false, None) => Ok(Some(Self::Json)),
-            (None, false, true, false, None) => Ok(Some(Self::Geo)),
-            (None, false, false, true, None) => Ok(Some(Self::ToString)),
-            (None, false, false, false, Some(ty)) => Ok(Some(Self::ToEnum(ty))),
-            (None, false, false, false, None) => Ok(None),
+        match (remote, json, geo, to_string, to_enum, uom_unit) {
+            (Some(ty), false, false, false, None, None) => Ok(Some(Self::Remote(ty))),
+            (None, true, false, false, None, None) => Ok(Some(Self::Json)),
+            (None, false, true, false, None, None) => Ok(Some(Self::Geo)),
+            (None, false, false, true, None, None) => Ok(Some(Self::ToString)),
+            (None, false, false, false, Some(ty), None) => Ok(Some(Self::ToEnum(ty))),
+            (None, false, false, false, None, Some(ty)) => Ok(Some(Self::UomUnit(ty))),
+            (None, false, false, false, None, None) => Ok(None),
             _ => Err(Error::custom(
-                "Model: remote, json, geo, to_string and to_enum attributes are mutually exclusive",
+                "Model: remote, json, geo, to_string, to_enum and uom_unit attributes are mutually exclusive",
             )),
         }
     }