From 4423275ce27b7d26b5418d4fda5bd74c39bd9697 Mon Sep 17 00:00:00 2001
From: Jimmy Cuadra <jimmy@jimmycuadra.com>
Date: Wed, 19 Jun 2019 22:40:58 -0700
Subject: [PATCH] Implement RoomEvent and StateEvent when applicable.

---
 src/gen.rs                  | 61 ++++++++++++++++++++++++++++++++++++-
 src/parse.rs                |  1 +
 tests/ruma_events_macros.rs | 31 +++++++++++++++++++
 3 files changed, 92 insertions(+), 1 deletion(-)

diff --git a/src/gen.rs b/src/gen.rs
index 894d96db..93c858e3 100644
--- a/src/gen.rs
+++ b/src/gen.rs
@@ -30,7 +30,6 @@ pub struct RumaEvent {
     fields: Vec<Field>,
 
     /// The kind of event.
-    #[allow(dead_code)]
     kind: EventKind,
 
     /// The name of the event.
@@ -199,6 +198,62 @@ impl ToTokens for RumaEvent {
             serialize_field_calls.push(serialize_field_call);
         }
 
+        let impl_room_event = match self.kind {
+            EventKind::RoomEvent | EventKind::StateEvent => {
+                quote! {
+                    impl crate::RoomEvent for #name {
+                        /// The unique identifier for the event.
+                        fn event_id(&self) -> &ruma_identifiers::EventId {
+                            &self.event_id
+                        }
+
+                        /// Timestamp (milliseconds since the UNIX epoch) on originating homeserver when this event was
+                        /// sent.
+                        fn origin_server_ts(&self) -> js_int::UInt {
+                            self.origin_server_ts
+                        }
+
+                        /// The unique identifier for the room associated with this event.
+                        ///
+                        /// This can be `None` if the event came from a context where there is
+                        /// no ambiguity which room it belongs to, like a `/sync` response for example.
+                        fn room_id(&self) -> Option<&ruma_identifiers::RoomId> {
+                            self.room_id.as_ref()
+                        }
+
+                        /// The unique identifier for the user who sent this event.
+                        fn sender(&self) -> &ruma_identifiers::UserId {
+                            &self.sender
+                        }
+
+                        /// Additional key-value pairs not signed by the homeserver.
+                        fn unsigned(&self) -> Option<&serde_json::Value> {
+                            self.unsigned.as_ref()
+                        }
+                    }
+                }
+            }
+            _ => TokenStream::new(),
+        };
+
+        let impl_state_event = if self.kind == EventKind::StateEvent {
+            quote! {
+                impl crate::StateEvent for #name {
+                    /// The previous content for this state key, if any.
+                    fn prev_content(&self) -> Option<&Self::Content> {
+                        self.prev_content.as_ref()
+                    }
+
+                    /// A key that determines which piece of room state the event represents.
+                    fn state_key(&self) -> &str {
+                        &self.state_key
+                    }
+                }
+            }
+        } else {
+            TokenStream::new()
+        };
+
         let output = quote!(
             #(#attrs)*
             #[derive(Clone, Debug)]
@@ -248,6 +303,10 @@ impl ToTokens for RumaEvent {
                 }
             }
 
+            #impl_room_event
+
+            #impl_state_event
+
             /// "Raw" versions of the event and its content which implement `serde::Deserialize`.
             mod raw {
                 use super::*;
diff --git a/src/parse.rs b/src/parse.rs
index 5077191c..266f8756 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -167,6 +167,7 @@ impl Parse for RumaEventInput {
 /// Which kind of event is being generated.
 ///
 /// Determined by the `kind` field in the macro body.
+#[derive(PartialEq)]
 pub enum EventKind {
     /// A basic event.
     Event,
diff --git a/tests/ruma_events_macros.rs b/tests/ruma_events_macros.rs
index e8257c6d..c3be78f7 100644
--- a/tests/ruma_events_macros.rs
+++ b/tests/ruma_events_macros.rs
@@ -35,6 +35,37 @@ where
     }
 }
 
+/// An event within the context of a room.
+pub trait RoomEvent: Event {
+    /// The unique identifier for the event.
+    fn event_id(&self) -> &ruma_identifiers::EventId;
+
+    /// Timestamp (milliseconds since the UNIX epoch) on originating homeserver when this event was
+    /// sent.
+    fn origin_server_ts(&self) -> js_int::UInt;
+
+    /// The unique identifier for the room associated with this event.
+    ///
+    /// This can be `None` if the event came from a context where there is
+    /// no ambiguity which room it belongs to, like a `/sync` response for example.
+    fn room_id(&self) -> Option<&ruma_identifiers::RoomId>;
+
+    /// The unique identifier for the user who sent this event.
+    fn sender(&self) -> &ruma_identifiers::UserId;
+
+    /// Additional key-value pairs not signed by the homeserver.
+    fn unsigned(&self) -> Option<&serde_json::Value>;
+}
+
+/// An event that describes persistent state about a room.
+pub trait StateEvent: RoomEvent {
+    /// The previous content for this state key, if any.
+    fn prev_content(&self) -> Option<&Self::Content>;
+
+    /// A key that determines which piece of room state the event represents.
+    fn state_key(&self) -> &str;
+}
+
 pub struct InvalidEvent;
 
 impl From<serde_json::Error> for InvalidEvent {