feat: initialize Kurdistan SDK - independent fork of Polkadot SDK

substrate/client/utils/src/notification/registry.rs

@@ -0,0 +1,62 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::collections::HashSet;
+
+use crate::{
+	id_sequence::SeqID,
+	pubsub::{Dispatch, Subscribe, Unsubscribe},
+};
+
+/// The shared structure to keep track on subscribers.
+#[derive(Debug, Default)]
+pub(super) struct Registry {
+	pub(super) subscribers: HashSet<SeqID>,
+}
+
+impl Subscribe<()> for Registry {
+	fn subscribe(&mut self, _subs_key: (), subs_id: SeqID) {
+		self.subscribers.insert(subs_id);
+	}
+}
+impl Unsubscribe for Registry {
+	fn unsubscribe(&mut self, subs_id: SeqID) {
+		self.subscribers.remove(&subs_id);
+	}
+}
+
+impl<MakePayload, Payload, Error> Dispatch<MakePayload> for Registry
+where
+	MakePayload: FnOnce() -> Result<Payload, Error>,
+	Payload: Clone,
+{
+	type Item = Payload;
+	type Ret = Result<(), Error>;
+
+	fn dispatch<F>(&mut self, make_payload: MakePayload, mut dispatch: F) -> Self::Ret
+	where
+		F: FnMut(&SeqID, Self::Item),
+	{
+		if !self.subscribers.is_empty() {
+			let payload = make_payload()?;
+			for subs_id in &self.subscribers {
+				dispatch(subs_id, payload.clone());
+			}
+		}
+		Ok(())
+	}
+}