From 98a1de91a2dae06323558422c239e5a45fc86e7b Mon Sep 17 00:00:00 2001
From: hozan23 <hozan23@proton.me>
Date: Tue, 28 Nov 2023 22:41:33 +0300
Subject: implement TLS for inbound and outbound connections

---
 core/src/async_util/task_group.rs | 194 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 194 insertions(+)
 create mode 100644 core/src/async_util/task_group.rs

(limited to 'core/src/async_util/task_group.rs')

diff --git a/core/src/async_util/task_group.rs b/core/src/async_util/task_group.rs
new file mode 100644
index 0000000..3fc0cb7
--- /dev/null
+++ b/core/src/async_util/task_group.rs
@@ -0,0 +1,194 @@
+use std::{future::Future, sync::Arc, sync::Mutex};
+
+use async_task::FallibleTask;
+
+use crate::Executor;
+
+use super::{select, CondWait, Either};
+
+/// TaskGroup is a group of spawned tasks.
+///
+/// # Example
+///
+/// ```
+///
+/// use std::sync::Arc;
+///
+/// use karyons_core::async_util::TaskGroup;
+///
+/// async {
+///
+///     let ex = Arc::new(smol::Executor::new());
+///     let group = TaskGroup::new(ex);
+///
+///     group.spawn(smol::Timer::never(), |_| async {});
+///
+///     group.cancel().await;
+///
+/// };
+///
+/// ```
+///
+pub struct TaskGroup<'a> {
+    tasks: Mutex<Vec<TaskHandler>>,
+    stop_signal: Arc<CondWait>,
+    executor: Executor<'a>,
+}
+
+impl<'a> TaskGroup<'a> {
+    /// Creates a new task group
+    pub fn new(executor: Executor<'a>) -> Self {
+        Self {
+            tasks: Mutex::new(Vec::new()),
+            stop_signal: Arc::new(CondWait::new()),
+            executor,
+        }
+    }
+
+    /// Spawns a new task and calls the callback after it has completed
+    /// or been canceled. The callback will have the `TaskResult` as a
+    /// parameter, indicating whether the task completed or was canceled.
+    pub fn spawn<T, Fut, CallbackF, CallbackFut>(&self, fut: Fut, callback: CallbackF)
+    where
+        T: Send + Sync + 'a,
+        Fut: Future<Output = T> + Send + 'a,
+        CallbackF: FnOnce(TaskResult<T>) -> CallbackFut + Send + 'a,
+        CallbackFut: Future<Output = ()> + Send + 'a,
+    {
+        let task = TaskHandler::new(
+            self.executor.clone(),
+            fut,
+            callback,
+            self.stop_signal.clone(),
+        );
+        self.tasks.lock().unwrap().push(task);
+    }
+
+    /// Checks if the task group is empty.
+    pub fn is_empty(&self) -> bool {
+        self.tasks.lock().unwrap().is_empty()
+    }
+
+    /// Get the number of the tasks in the group.
+    pub fn len(&self) -> usize {
+        self.tasks.lock().unwrap().len()
+    }
+
+    /// Cancels all tasks in the group.
+    pub async fn cancel(&self) {
+        self.stop_signal.broadcast().await;
+
+        loop {
+            let task = self.tasks.lock().unwrap().pop();
+            if let Some(t) = task {
+                t.cancel().await
+            } else {
+                break;
+            }
+        }
+    }
+}
+
+/// The result of a spawned task.
+#[derive(Debug)]
+pub enum TaskResult<T> {
+    Completed(T),
+    Cancelled,
+}
+
+impl<T: std::fmt::Debug> std::fmt::Display for TaskResult<T> {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        match self {
+            TaskResult::Cancelled => write!(f, "Task cancelled"),
+            TaskResult::Completed(res) => write!(f, "Task completed: {:?}", res),
+        }
+    }
+}
+
+/// TaskHandler
+pub struct TaskHandler {
+    task: FallibleTask<()>,
+    cancel_flag: Arc<CondWait>,
+}
+
+impl<'a> TaskHandler {
+    /// Creates a new task handle
+    fn new<T, Fut, CallbackF, CallbackFut>(
+        ex: Executor<'a>,
+        fut: Fut,
+        callback: CallbackF,
+        stop_signal: Arc<CondWait>,
+    ) -> TaskHandler
+    where
+        T: Send + Sync + 'a,
+        Fut: Future<Output = T> + Send + 'a,
+        CallbackF: FnOnce(TaskResult<T>) -> CallbackFut + Send + 'a,
+        CallbackFut: Future<Output = ()> + Send + 'a,
+    {
+        let cancel_flag = Arc::new(CondWait::new());
+        let cancel_flag_c = cancel_flag.clone();
+        let task = ex
+            .spawn(async move {
+                //start_signal.signal().await;
+                // Waits for either the stop signal or the task to complete.
+                let result = select(stop_signal.wait(), fut).await;
+
+                let result = match result {
+                    Either::Left(_) => TaskResult::Cancelled,
+                    Either::Right(res) => TaskResult::Completed(res),
+                };
+
+                // Call the callback with the result.
+                callback(result).await;
+
+                cancel_flag_c.signal().await;
+            })
+            .fallible();
+
+        TaskHandler { task, cancel_flag }
+    }
+
+    /// Cancels the task.
+    async fn cancel(self) {
+        self.cancel_flag.wait().await;
+        self.task.cancel().await;
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::{future, sync::Arc};
+
+    #[test]
+    fn test_task_group() {
+        let ex = Arc::new(smol::Executor::new());
+        smol::block_on(ex.clone().run(async move {
+            let group = Arc::new(TaskGroup::new(ex));
+
+            group.spawn(future::ready(0), |res| async move {
+                assert!(matches!(res, TaskResult::Completed(0)));
+            });
+
+            group.spawn(future::pending::<()>(), |res| async move {
+                assert!(matches!(res, TaskResult::Cancelled));
+            });
+
+            let groupc = group.clone();
+            group.spawn(
+                async move {
+                    groupc.spawn(future::pending::<()>(), |res| async move {
+                        assert!(matches!(res, TaskResult::Cancelled));
+                    });
+                },
+                |res| async move {
+                    assert!(matches!(res, TaskResult::Completed(_)));
+                },
+            );
+
+            // Do something
+            smol::Timer::after(std::time::Duration::from_millis(50)).await;
+            group.cancel().await;
+        }));
+    }
+}
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