Add m.receipt event.

src/receipt.rs

@@ -1 +1,41 @@
 //! Events within the *m.receipt* namespace.
+
+use std::collections::HashMap;
+
+use core::Event;
+
+/// Informs the client of new receipts.
+pub struct ReceiptEvent<'a> {
+    content: ReceiptEventContent<'a>,
+    room_id: &'a str,
+}
+
+impl<'a> Event<'a, ReceiptEventContent<'a>> for ReceiptEvent<'a> {
+    fn content(&'a self) -> &'a ReceiptEventContent {
+        &self.content
+    }
+
+    fn event_type(&self) -> &'static str {
+        "m.receipt"
+    }
+}
+
+/// The payload of a `ReceiptEvent`. The mapping of event ID to a collection of receipts for this
+/// event ID. The event ID is the ID of the event being acknowledged and *not* an ID for the receipt
+/// itself.
+pub type ReceiptEventContent<'a> = HashMap<&'a str, Receipts<'a>>;
+
+/// A collection of receipts.
+pub struct Receipts<'a> {
+    /// A collection of users who have sent *m.read* receipts for this event.
+    m_read: UserReceipts<'a>,
+}
+
+/// The mapping of user ID to receipt. The user ID is the entity who sent this receipt.
+pub type UserReceipts<'a> = HashMap<&'a str, Receipt>;
+
+/// An acknowledgement of an event.
+pub struct Receipt {
+    /// The timestamp the receipt was sent at.
+    ts: u64,
+}