Move event content derives into one place and share code

ruma-events-macros/src/event_content.rs

@@ -1,4 +1,4 @@
-//! Implementation of the `StateEventContent` derive macro
+//! Implementations of the MessageEventContent and StateEventContent derive macro.
 
 use proc_macro2::{Span, TokenStream};
 use quote::quote;
@@ -11,7 +11,7 @@ use syn::{
 ///
 /// `#[ruma_event(type = "m.room.alias")]`
 enum EventMeta {
-    /// Variant holds the "m.room.whatever" event type.
+    /// Variant holds the "m.whatever" event type.
     Type(LitStr),
 }
 
@@ -23,8 +23,10 @@ impl Parse for EventMeta {
     }
 }
 
-/// Create a `StateEventContent` implementation for a struct
-pub fn expand_state_event(input: DeriveInput) -> syn::Result<TokenStream> {
+/// Create a `RoomEventContent` implementation for a struct.
+///
+/// This is used internally for code sharing as `RoomEventContent` is not derivable.
+fn expand_room_event(input: DeriveInput) -> syn::Result<TokenStream> {
     let ident = &input.ident;
 
     let event_type_attr = input
@@ -72,6 +74,28 @@ pub fn expand_state_event(input: DeriveInput) -> syn::Result<TokenStream> {
         #event_content_impl
 
         impl ::ruma_events::RoomEventContent for #ident { }
+    })
+}
+
+/// Create a `MessageEventContent` implementation for a struct
+pub fn expand_message_event(input: DeriveInput) -> syn::Result<TokenStream> {
+    let ident = input.ident.clone();
+    let room_ev_content = expand_room_event(input)?;
+
+    Ok(quote! {
+        #room_ev_content
+
+        impl ::ruma_events::MessageEventContent for #ident { }
+    })
+}
+
+/// Create a `MessageEventContent` implementation for a struct
+pub fn expand_state_event(input: DeriveInput) -> syn::Result<TokenStream> {
+    let ident = input.ident.clone();
+    let room_ev_content = expand_room_event(input)?;
+
+    Ok(quote! {
+        #room_ev_content
 
         impl ::ruma_events::StateEventContent for #ident { }
     })

ruma-events-macros/src/lib.rs

@@ -37,13 +37,16 @@ use quote::ToTokens;
 use syn::{parse_macro_input, DeriveInput};
 
 use self::{
-    from_raw::expand_from_raw, gen::RumaEvent, parse::RumaEventInput, state::expand_state_event,
+    event_content::{expand_message_event, expand_state_event},
+    from_raw::expand_from_raw,
+    gen::RumaEvent,
+    parse::RumaEventInput,
 };
 
+mod event_content;
 mod from_raw;
 mod gen;
 mod parse;
-mod state;
 
 // A note about the `example` modules that appears in doctests:
 //
@@ -149,6 +152,15 @@ pub fn derive_from_raw(input: TokenStream) -> TokenStream {
         .into()
 }
 
+/// Generates an implementation of `ruma_events::MessageEventContent` and it's super traits.
+#[proc_macro_derive(MessageEventContent, attributes(ruma_event))]
+pub fn derive_message_event_content(input: TokenStream) -> TokenStream {
+    let input = parse_macro_input!(input as DeriveInput);
+    expand_message_event(input)
+        .unwrap_or_else(|err| err.to_compile_error())
+        .into()
+}
+
 /// Generates an implementation of `ruma_events::StateEventContent` and it's super traits.
 #[proc_macro_derive(StateEventContent, attributes(ruma_event))]
 pub fn derive_state_event_content(input: TokenStream) -> TokenStream {