TryFromRpcValue: Add support for generic structs

silicon-heaven · Jul 10, 2024 · c770d29 · c770d29
1 parent 1514c97
commit c770d29
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Showing 2 changed files with 33 additions and 10 deletions.
diff --git a/libshvproto-macros/src/lib.rs b/libshvproto-macros/src/lib.rs
@@ -41,6 +41,15 @@ fn get_type(ty: &syn::Type) -> Option<String> {
 pub fn derive_from_rpcvalue(item: TokenStream) -> TokenStream {
     let input = syn::parse_macro_input!(item as syn::DeriveInput);
     let struct_identifier = &input.ident;
+    let struct_generics = &input.generics;
+    let struct_generics_without_bounds_vec = input.generics.params.clone().into_iter().map(|generic_param|
+        if let syn::GenericParam::Type(mut type_param) = generic_param {
+            type_param.bounds.clear();
+            syn::GenericParam::Type(type_param)
+        } else {
+            generic_param
+        }).collect::<Vec<_>>();
+    let struct_generics_without_bounds = quote!(<#(#struct_generics_without_bounds_vec),*>);
 
     match &input.data {
         syn::Data::Struct(syn::DataStruct { fields, .. }) => {
@@ -75,8 +84,9 @@ pub fn derive_from_rpcvalue(item: TokenStream) -> TokenStream {
                     });
                 }
             }
+
             quote!{
-                impl TryFrom<shvproto::RpcValue> for #struct_identifier {
+                impl #struct_generics TryFrom<shvproto::RpcValue> for #struct_identifier #struct_generics_without_bounds {
                     type Error = String;
                     fn try_from(value: shvproto::RpcValue) -> Result<Self, Self::Error> {
                         if let shvproto::Value::Map(value) = value.value() {
@@ -87,7 +97,7 @@ pub fn derive_from_rpcvalue(item: TokenStream) -> TokenStream {
                     }
                 }
 
-                impl TryFrom<&shvproto::RpcValue> for #struct_identifier {
+                impl #struct_generics TryFrom<&shvproto::RpcValue> for #struct_identifier #struct_generics_without_bounds {
                     type Error = String;
                     fn try_from(value: &shvproto::RpcValue) -> Result<Self, Self::Error> {
                         if let shvproto::Value::Map(value) = value.value() {
@@ -98,14 +108,14 @@ pub fn derive_from_rpcvalue(item: TokenStream) -> TokenStream {
                     }
                 }
 
-                impl TryFrom<&Box<shvproto::Map>> for #struct_identifier {
+                impl #struct_generics  TryFrom<&Box<shvproto::Map>> for #struct_identifier #struct_generics_without_bounds  {
                     type Error = String;
                     fn try_from(value: &Box<shvproto::Map>) -> Result<Self, Self::Error> {
                         value.as_ref().try_into()
                     }
                 }
 
-                impl TryFrom<&shvproto::Map> for #struct_identifier {
+                impl #struct_generics TryFrom<&shvproto::Map> for #struct_identifier #struct_generics_without_bounds  {
                     type Error = String;
                     fn try_from(value: &shvproto::Map) -> Result<Self, Self::Error> {
                         let get_key = |key_name| value.get(key_name).ok_or_else(|| "Missing ".to_string() + key_name + " key");
@@ -115,15 +125,15 @@ pub fn derive_from_rpcvalue(item: TokenStream) -> TokenStream {
                     }
                 }
 
-                impl TryFrom<shvproto::Map> for #struct_identifier {
+                impl #struct_generics TryFrom<shvproto::Map> for #struct_identifier #struct_generics_without_bounds {
                     type Error = String;
                     fn try_from(value: shvproto::Map) -> Result<Self, Self::Error> {
                         Self::try_from(&value)
                     }
                 }
 
-                impl From<#struct_identifier> for shvproto::RpcValue {
-                    fn from(value: #struct_identifier) -> Self {
+                impl #struct_generics From<#struct_identifier #struct_generics_without_bounds> for shvproto::RpcValue {
+                    fn from(value: #struct_identifier #struct_generics_without_bounds) -> Self {
                         let mut map = shvproto::rpcvalue::Map::new();
                         #rpcvalue_inserts
                         map.into()

diff --git a/tests/test.rs b/tests/test.rs
@@ -2,8 +2,7 @@
 mod test {
     use std::collections::BTreeMap;
 
-    use libshvproto_macros::TryFromRpcValue;
-    use shvproto::RpcValue;
+    use shvproto::{RpcValue, TryFromRpcValue};
 
     #[derive(Clone,Debug,PartialEq,TryFromRpcValue)]
     pub struct EmptyStruct {
@@ -71,7 +70,7 @@ mod test {
             "mapIntField" => [("aaa".to_string(), 111)].into_iter().collect::<BTreeMap<_,_>>(),
             "imapField" => [(420, 111)].into_iter().collect::<BTreeMap<_,_>>(),
         ).into();
-    
+
         let y: TestStruct = x.clone().try_into().expect("Failed to parse");
         assert_eq!(x, y.into());
     }
@@ -135,4 +134,18 @@ mod test {
         let input: RpcValue = String::new().into();
         let _output: EnumWithUserStruct = input.try_into().expect("Expected failure");
     }
+
+    #[derive(Clone,Debug,PartialEq,TryFromRpcValue)]
+    pub struct GenericStruct<T: Into<RpcValue> + for<'a> TryFrom<&'a RpcValue, Error = String>> {
+        x: T
+    }
+
+    #[test]
+    fn generic_struct() {
+        let int_struct_in: GenericStruct::<i64> = shvproto::make_map!("x" => 123).try_into().expect("Failed to parse");
+        let int_struct_rpcvalue: RpcValue = int_struct_in.clone().into();
+        let int_struct_out: GenericStruct::<i64> = int_struct_rpcvalue.clone().try_into().expect("Failed to parse");
+        assert_eq!(int_struct_in, int_struct_out);
+
+    }
 }