Add EventKind trait.

src/lib.rs

@@ -20,6 +20,20 @@ pub mod stripped;
 pub mod tag;
 pub mod typing;
 
+/// A basic event.
+#[derive(Debug, Deserialize, Serialize)]
+pub struct Event<T> where T: Deserialize + Serialize {
+    pub content: T,
+    #[serde(rename="type")]
+    pub event_type: EventType,
+}
+
+/// A type that represents a kind of Matrix event.
+///
+/// The event kinds are basic events, room events, and state events.
+/// This trait can be useful to constrain a generic parameter that must be a Matrix event.
+pub trait EventKind: Deserialize + Serialize {}
+
 /// The type of an event.
 #[derive(Debug, Deserialize, Serialize)]
 pub enum EventType {
@@ -47,14 +61,6 @@ pub enum EventType {
     Typing,
 }
 
-/// A basic event.
-#[derive(Debug, Deserialize, Serialize)]
-pub struct Event<T> where T: Deserialize + Serialize {
-    pub content: T,
-    #[serde(rename="type")]
-    pub event_type: EventType,
-}
-
 /// An event within the context of a room.
 #[derive(Debug, Deserialize, Serialize)]
 pub struct RoomEvent<T> where T: Deserialize + Serialize {
@@ -83,6 +89,10 @@ pub struct StateEvent<T> where T: Deserialize + Serialize {
     pub user_id: String,
 }
 
+impl<T> EventKind for Event<T> where T: Deserialize + Serialize {}
+impl<T> EventKind for RoomEvent<T> where T: Deserialize + Serialize {}
+impl<T> EventKind for StateEvent<T> where T: Deserialize + Serialize {}
+
 impl Display for EventType {
     fn fmt(&self, f: &mut Formatter) -> Result<(), FmtError> {
         let event_type_str = match *self {

src/presence.rs

@@ -1,6 +1,6 @@
 //! Types for the *m.presence* event.
 
-use EventType;
+use {EventKind, EventType};
 
 /// Informs the client of a user's presence state change.
 #[derive(Debug, Deserialize, Serialize)]
@@ -38,3 +38,5 @@ pub enum PresenceState {
     /// Connected to the service but not available for chat.
     Unavailable,
 }
+
+impl EventKind for PresenceEvent {}

src/receipt.rs

@@ -2,7 +2,7 @@
 
 use std::collections::HashMap;
 
-use EventType;
+use {EventKind, EventType};
 
 /// Informs the client of new receipts.
 #[derive(Debug, Deserialize, Serialize)]
@@ -37,3 +37,5 @@ pub struct Receipt {
     /// The timestamp the receipt was sent at.
     pub ts: u64,
 }
+
+impl EventKind for ReceiptEvent {}

src/typing.rs

@@ -1,6 +1,6 @@
 //! Types for the *m.typing* event.
 
-use EventType;
+use {EventKind, EventType};
 
 /// Informs the client of the list of users currently typing.
 #[derive(Debug, Deserialize, Serialize)]
@@ -19,3 +19,5 @@ pub struct TypingEventContent {
     /// The list of user IDs typing in this room, if any.
     pub user_ids: Vec<String>,
 }
+
+impl EventKind for TypingEvent {}