block_on method

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * CAN driver: support for pulling alerts in blocking and async mode
 * UART driver: support for pulling UART events
 * `task` and `interrupt` modules: new submodule in each - `asynch` - featuring a signal/notification-like synchronization primitive
+* `task` module: `block_on` method capable of executing a future on the current thread
 * `task` module: new sub-module - `queue` for the FreeRTOS `queue` synchonization primitive
 * `task` module: new sub-module - `notification` - a more ergonomic API around the FreeRTOS task notification API
    which was already exposed via the `task::notify` and `task::wait_notification` APIs

src/task.rs

@@ -1,7 +1,10 @@
 use core::cell::Cell;
+use core::future::Future;
 use core::num::NonZeroU32;
+use core::pin::pin;
 use core::ptr::{self, NonNull};
 use core::sync::atomic::{AtomicBool, Ordering};
+use core::task::{Context, Poll};
 
 use esp_idf_sys::*;
 
@@ -214,6 +217,33 @@ pub fn get_idle_task(core: crate::cpu::Core) -> TaskHandle_t {
     }
 }
 
+/// Executes the supplied future on the current thread, thus blocking it until the future becomes ready.
+pub fn block_on<F>(mut fut: F) -> F::Output
+where
+    F: Future,
+{
+    log::trace!("block_on(): started");
+
+    let notification = notification::Notification::new();
+
+    let mut fut = pin!(fut);
+
+    let waker = notification.notifier().into();
+
+    let mut cx = Context::from_waker(&waker);
+
+    let res = loop {
+        match fut.as_mut().poll(&mut cx) {
+            Poll::Ready(res) => break res,
+            Poll::Pending => notification.wait_any(),
+        }
+    };
+
+    log::trace!("block_on(): finished");
+
+    res
+}
+
 #[cfg(esp_idf_comp_pthread_enabled)]
 pub mod thread {
     use core::ffi::CStr;