[v2.0] Move exchange keys into User

streams/src/api/cursor_store.rs

@@ -0,0 +1,51 @@
+// Rust
+use core::fmt;
+
+// 3rd-party
+use hashbrown::HashMap;
+
+// IOTA
+
+// Streams
+use lets::id::Identifier;
+
+// Local
+
+#[derive(Default, Clone, PartialEq, Eq)]
+pub(crate) struct CursorStore(HashMap<Identifier, usize>);
+
+impl CursorStore {
+    pub(crate) fn new() -> Self {
+        Default::default()
+    }
+
+    pub(crate) fn is_cursor_tracked(&self, id: &Identifier) -> bool {
+        self.0.contains_key(id)
+    }
+
+    pub(crate) fn get_cursor(&self, id: &Identifier) -> Option<usize> {
+        self.0.get(id).copied()
+    }
+
+    pub(crate) fn insert_cursor(&mut self, id: Identifier, cursor: usize) -> bool {
+        self.0.insert(id, cursor).is_none()
+    }
+
+    pub(crate) fn cursors(&self) -> impl Iterator<Item = (Identifier, usize)> + ExactSizeIterator + Clone + '_ {
+        self.0.iter().map(|(identifier, cursor)| (*identifier, *cursor))
+    }
+
+    pub(crate) fn remove(&mut self, id: &Identifier) -> bool {
+        self.0.remove(id).is_some()
+    }
+}
+
+impl fmt::Debug for CursorStore {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        writeln!(f, "* cursors:")?;
+        for (id, cursor) in self.cursors() {
+            writeln!(f, "\t{:?} => {}", id, cursor)?;
+        }
+        Ok(())
+    }
+}

streams/src/api/mod.rs

@@ -1,5 +1,5 @@
 /// Identifier Key storage. Used for keeping track of channel state
-mod key_store;
+mod cursor_store;
 
 pub(crate) mod message;
 mod messages;