From 689d911cdcbb333d760d4d9c22ab68941c28f04d Mon Sep 17 00:00:00 2001
From: Jonathan de Jong <jonathan@automatia.nl>
Date: Wed, 9 Feb 2022 17:54:57 +0100
Subject: [PATCH] api-macros: Simplify IncomingRequest impl generation

---
 crates/ruma-api-macros/src/request.rs         | 12 ++++++++++--
 .../ruma-api-macros/src/request/incoming.rs   | 19 +++----------------
 2 files changed, 13 insertions(+), 18 deletions(-)

diff --git a/crates/ruma-api-macros/src/request.rs b/crates/ruma-api-macros/src/request.rs
index e47dd0fe..2c85b7f3 100644
--- a/crates/ruma-api-macros/src/request.rs
+++ b/crates/ruma-api-macros/src/request.rs
@@ -152,8 +152,8 @@ impl Request {
         self.fields.iter().filter(|f| matches!(f, RequestField::Header(..)))
     }
 
-    fn path_field_count(&self) -> usize {
-        self.fields.iter().filter(|f| matches!(f, RequestField::Path(..))).count()
+    fn path_fields(&self) -> impl Iterator<Item = &Field> {
+        self.fields.iter().filter_map(RequestField::as_path_field)
     }
 
     fn raw_body_field(&self) -> Option<&Field> {
@@ -357,6 +357,14 @@ impl RequestField {
         }
     }
 
+    /// Return the contained field if this request field is a path kind.
+    pub fn as_path_field(&self) -> Option<&Field> {
+        match self {
+            RequestField::Path(field) => Some(field),
+            _ => None,
+        }
+    }
+
     /// Return the contained field if this request field is a query kind.
     pub fn as_query_field(&self) -> Option<&Field> {
         match self {
diff --git a/crates/ruma-api-macros/src/request/incoming.rs b/crates/ruma-api-macros/src/request/incoming.rs
index b0bc76be..dc4be593 100644
--- a/crates/ruma-api-macros/src/request/incoming.rs
+++ b/crates/ruma-api-macros/src/request/incoming.rs
@@ -1,4 +1,4 @@
-use proc_macro2::{Ident, Span, TokenStream};
+use proc_macro2::TokenStream;
 use quote::quote;
 use syn::Field;
 
@@ -25,20 +25,7 @@ impl Request {
         // except this one. If we get errors about missing fields in IncomingRequest for
         // a path field look here.
         let (parse_request_path, path_vars) = if self.has_path_fields() {
-            let path_string = self.path.value();
-
-            assert!(path_string.starts_with('/'), "path needs to start with '/'");
-            assert!(
-                path_string.chars().filter(|c| *c == ':').count() == self.path_field_count(),
-                "number of declared path parameters needs to match amount of placeholders in path"
-            );
-
-            let path_vars = path_string[1..]
-                .split('/')
-                .filter(|seg| seg.starts_with(':'))
-                .map(|seg| Ident::new(&seg[1..], Span::call_site()));
-
-            let vars = path_vars.clone();
+            let path_vars: Vec<_> = self.path_fields().filter_map(|f| f.ident.as_ref()).collect();
 
             let parse_request_path = quote! {
                 let (#(#path_vars,)*) = #serde::Deserialize::deserialize(
@@ -48,7 +35,7 @@ impl Request {
                 )?;
             };
 
-            (parse_request_path, quote! { #(#vars,)* })
+            (parse_request_path, quote! { #(#path_vars,)* })
         } else {
             (TokenStream::new(), TokenStream::new())
         };