orch: Add an async select macro

Added a basic implementation of the async select macro.
No conditionals or a default case for now.

Author: maciejbacalext

src/async_runtime/examples/select.rs

@@ -0,0 +1,133 @@
+//
+// Copyright (c) 2025 Contributors to the Eclipse Foundation
+//
+// See the NOTICE file(s) distributed with this work for additional
+// information regarding copyright ownership.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Apache License Version 2.0 which is available at
+// <https://www.apache.org/licenses/LICENSE-2.0>
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+use async_runtime::{
+    prelude::*,
+    runtime::async_runtime::AsyncRuntimeBuilder,
+    safety::{ensure_safety_enabled, spawn, SafetyResult},
+    scheduler::execution_engine::*,
+    select,
+};
+use foundation::prelude::*;
+
+fn main() {
+    tracing_subscriber::fmt()
+        // .with_span_events(FmtSpan::FULL) // Ensures span open/close events are logged
+        .with_target(false) // Optional: Remove module path
+        .with_max_level(Level::DEBUG)
+        .with_thread_ids(true)
+        .with_thread_names(true)
+        .init();
+
+    let (builder, _engine_id) = AsyncRuntimeBuilder::new().with_engine(
+        ExecutionEngineBuilder::new()
+            .task_queue_size(256)
+            .workers(4)
+            .with_dedicated_worker("dedicated".into(), ThreadParameters::default())
+            .enable_safety_worker(ThreadParameters::default()),
+    );
+    let mut runtime = builder.build().unwrap();
+
+    let _ = runtime.block_on(async {
+        ensure_safety_enabled();
+
+        async fn short_job(result: i32) -> SafetyResult<i32, ()> {
+            for _ in 0..1_000_usize {}
+            Ok(result)
+        }
+
+        async fn long_job(result: i32) -> SafetyResult<i32, ()> {
+            for _ in 0..1_000_000_usize {}
+            Ok(result)
+        }
+
+        async fn very_long_job(result: i32) -> SafetyResult<i32, ()> {
+            for _ in 0..1_000_000_000_usize {}
+            Ok(result)
+        }
+
+        // First job should finish first.
+        {
+            info!("Test 1");
+
+            let mut fut1 = spawn(short_job(111));
+            let mut fut2 = spawn(long_job(222));
+            let mut fut3 = spawn(long_job(333));
+            let mut result = 0;
+
+            select! {
+                Ok(Ok(var1)) = fut1 => {
+                    result = var1;
+                }
+                Ok(Ok(var2)) = fut2 => {
+                    result = var2;
+                }
+                Ok(Ok(var3)) = fut3 => {
+                    result = var3;
+                }
+            }
+
+            assert_eq!(result, 111);
+        }
+
+        // Second job should finish first.
+        {
+            info!("Test 2");
+
+            let mut fut1 = spawn(long_job(111));
+            let mut fut2 = spawn(short_job(222));
+            let mut fut3 = spawn(long_job(333));
+            let mut result = 0;
+
+            select! {
+                Ok(Ok(var1)) = fut1 => {
+                    result = var1;
+                }
+                Ok(Ok(var2)) = fut2 => {
+                    result = var2;
+                }
+                Ok(Ok(var3)) = fut3 => {
+                    result = var3;
+                }
+            }
+
+            assert_eq!(result, 222);
+        }
+
+        // First job should finish first, but it won't match, so the third job should match first.
+        {
+            info!("Test 3");
+
+            let mut fut1 = spawn(short_job(111));
+            let mut fut2 = spawn(very_long_job(222));
+            let mut fut3 = spawn(long_job(333));
+            let mut result = 0;
+
+            select! {
+                Ok(Err(())) = fut1 => {
+                    result = 111;
+                }
+                Ok(Ok(var2)) = fut2 => {
+                    result = var2;
+                }
+                Ok(Ok(var3)) = fut3 => {
+                    result = var3;
+                }
+            }
+
+            assert_eq!(result, 333);
+        }
+
+        Ok(0)
+    });
+}

src/async_runtime/src/lib.rs

@@ -58,6 +58,7 @@ pub mod core;
 pub mod futures;
 pub mod io;
 pub mod ipc;
+pub mod macros;
 pub mod mio;
 pub mod net;
 pub mod prelude;

src/async_runtime/src/macros/mod.rs

@@ -0,0 +1,14 @@
+//
+// Copyright (c) 2025 Contributors to the Eclipse Foundation
+//
+// See the NOTICE file(s) distributed with this work for additional
+// information regarding copyright ownership.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Apache License Version 2.0 which is available at
+// <https://www.apache.org/licenses/LICENSE-2.0>
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+pub mod select;