From 4e72c374b93d7e4556b52a9a6141bc47133804d3 Mon Sep 17 00:00:00 2001
From: Jonas Platte <jplatte+git@posteo.de>
Date: Thu, 12 Aug 2021 11:59:00 +0200
Subject: [PATCH] api-macros: Small refactor

---
 crates/ruma-api-macros/src/request.rs         | 20 ++++++-------------
 crates/ruma-api-macros/src/response.rs        |  8 ++++++++
 .../ruma-api-macros/src/response/outgoing.rs  | 18 +++++++----------
 3 files changed, 21 insertions(+), 25 deletions(-)

diff --git a/crates/ruma-api-macros/src/request.rs b/crates/ruma-api-macros/src/request.rs
index 99425cc5..d9599e15 100644
--- a/crates/ruma-api-macros/src/request.rs
+++ b/crates/ruma-api-macros/src/request.rs
@@ -187,12 +187,8 @@ impl Request {
             // for lifetimes, the outer check and the macro failing if it encounters
             // an illegal combination of field attributes, is enough to guarantee
             // `body_lifetimes` correctness.
-            let (derive_deserialize, generics) = if self.lifetimes.body.is_empty() {
-                (quote! { #serde::Deserialize }, TokenStream::new())
-            } else {
-                let lifetimes = &self.lifetimes.body;
-                (TokenStream::new(), quote! { < #(#lifetimes),* > })
-            };
+            let lifetimes = &self.lifetimes.body;
+            let derive_deserialize = lifetimes.is_empty().then(|| quote! { #serde::Deserialize });
 
             quote! {
                 /// Data in the request body.
@@ -203,7 +199,7 @@ impl Request {
                     #serde::Serialize,
                     #derive_deserialize
                 )]
-                struct RequestBody #generics #def
+                struct RequestBody< #(#lifetimes),* > #def
             }
         });
 
@@ -218,12 +214,8 @@ impl Request {
         };
 
         let request_query_struct = request_query_def.map(|def| {
-            let (derive_deserialize, generics) = if self.lifetimes.query.is_empty() {
-                (quote! { #serde::Deserialize }, TokenStream::new())
-            } else {
-                let lifetimes = &self.lifetimes.query;
-                (TokenStream::new(), quote! { < #(#lifetimes),* > })
-            };
+            let lifetimes = &self.lifetimes.query;
+            let derive_deserialize = lifetimes.is_empty().then(|| quote! { #serde::Deserialize });
 
             quote! {
                 /// Data in the request's query string.
@@ -234,7 +226,7 @@ impl Request {
                     #serde::Serialize,
                     #derive_deserialize
                 )]
-                struct RequestQuery #generics #def
+                struct RequestQuery< #(#lifetimes),* > #def
             }
         });
 
diff --git a/crates/ruma-api-macros/src/response.rs b/crates/ruma-api-macros/src/response.rs
index 9542bcb5..cb40886e 100644
--- a/crates/ruma-api-macros/src/response.rs
+++ b/crates/ruma-api-macros/src/response.rs
@@ -194,6 +194,14 @@ impl ResponseField {
         }
     }
 
+    /// Return the contained field and HTTP header ident if this repsonse field is a header kind.
+    fn as_header_field(&self) -> Option<(&Field, &Ident)> {
+        match self {
+            ResponseField::Header(field, ident) => Some((field, ident)),
+            _ => None,
+        }
+    }
+
     /// Return the contained field if this response field is a newtype body kind.
     fn as_newtype_body_field(&self) -> Option<&Field> {
         match self {
diff --git a/crates/ruma-api-macros/src/response/outgoing.rs b/crates/ruma-api-macros/src/response/outgoing.rs
index f3adc6c5..8a526dc6 100644
--- a/crates/ruma-api-macros/src/response/outgoing.rs
+++ b/crates/ruma-api-macros/src/response/outgoing.rs
@@ -1,7 +1,7 @@
 use proc_macro2::TokenStream;
 use quote::quote;
 
-use super::{Response, ResponseField};
+use super::Response;
 
 impl Response {
     pub fn expand_outgoing(&self, ruma_api: &TokenStream) -> TokenStream {
@@ -9,8 +9,8 @@ impl Response {
         let http = quote! { #ruma_api::exports::http };
         let ruma_serde = quote! { #ruma_api::exports::ruma_serde };
 
-        let serialize_response_headers = self.fields.iter().map(|response_field| {
-            if let ResponseField::Header(field, header_name) = response_field {
+        let serialize_response_headers = self.fields.iter().filter_map(|response_field| {
+            response_field.as_header_field().map(|(field, header_name)| {
                 let field_name =
                     field.ident.as_ref().expect("expected field to have an identifier");
 
@@ -34,9 +34,7 @@ impl Response {
                         );
                     },
                 }
-            } else {
-                TokenStream::new()
-            }
+            })
         });
 
         let body = if let Some(field) = self.newtype_raw_body_field() {
@@ -48,8 +46,8 @@ impl Response {
                 #ruma_serde::json_to_buf(&self.#field_name)?
             }
         } else {
-            let fields = self.fields.iter().map(|response_field| {
-                if let ResponseField::Body(field) = response_field {
+            let fields = self.fields.iter().filter_map(|response_field| {
+                response_field.as_body_field().map(|field| {
                     let field_name =
                         field.ident.as_ref().expect("expected field to have an identifier");
                     let cfg_attrs = field.attrs.iter().filter(|a| a.path.is_ident("cfg"));
@@ -58,9 +56,7 @@ impl Response {
                         #( #cfg_attrs )*
                         #field_name: self.#field_name,
                     }
-                } else {
-                    TokenStream::new()
-                }
+                })
             });
 
             quote! {