Add Safe Abstractions for FuriStreamBuffer (#177)

Co-authored-by: Petr Portnov | PROgrm_JARvis <me@progrm-jarvis.ru>

crates/flipperzero/Cargo.toml

@@ -80,6 +80,10 @@ harness = false
 name = "dialog"
 required-features = ["alloc"]
 
+[[example]]
+name = "stream_buffer"
+required-features = ["alloc"]
+
 [[example]]
 name = "threads"
 required-features = ["alloc"]

crates/flipperzero/examples/stream_buffer.rs

@@ -0,0 +1,89 @@
+//! Example showcasing the use of a stream buffer on multiple threads.
+
+#![no_main]
+#![no_std]
+
+// Required for panic handler
+extern crate flipperzero_rt;
+
+// Required for allocator
+extern crate flipperzero_alloc;
+
+extern crate alloc;
+
+use core::{ffi::CStr, num::NonZeroUsize};
+
+use flipperzero::{furi, println};
+use flipperzero_rt::{entry, manifest};
+
+use core::time::Duration as CoreDuration;
+use furi::time::Duration as FuriDuration;
+
+// Define the FAP Manifest for this application
+manifest!(name = "Stream buffer example");
+
+// Define the entry function
+entry!(main);
+
+// Entry point
+fn main(_args: Option<&CStr>) -> i32 {
+    // Create a stream buffer pair
+    let size = NonZeroUsize::new(1024).unwrap();
+    let trigger_level = 16;
+    let stream_buffer = furi::stream_buffer::StreamBuffer::new(size, trigger_level);
+    let (tx, rx) = stream_buffer.into_stream();
+
+    let stream_buffer = tx.as_stream_buffer();
+
+    // Stream buffer is empty
+    assert_eq!(stream_buffer.spaces_available(), size.into());
+    assert_eq!(stream_buffer.bytes_available(), 0);
+
+    // Sending 4 bytes immediately
+    assert_eq!(tx.send(&[1, 2, 3, 4]), 4);
+    assert_eq!(stream_buffer.bytes_available(), 4);
+
+    // Receive bytes
+    let mut recv_buf = [0; 32];
+    assert_eq!(rx.recv(&mut recv_buf), 4);
+    assert_eq!(recv_buf[0..4], [1, 2, 3, 4]);
+
+    // Move sender to another thread
+    let tx_thread = furi::thread::spawn(move || {
+        // Wait 2 seconds before we send some bytes
+        furi::thread::sleep(CoreDuration::from_secs(2));
+        assert_eq!(tx.send(&[5; 20]), 20);
+
+        // Send some bytes in a loop to see how the receiver handles them
+        for i in 4..20 {
+            furi::thread::sleep(CoreDuration::from_millis(200));
+            tx.send(&[i as u8; 3]);
+        }
+
+        0
+    });
+
+    // Move receiver to another thread
+    let rx_thread = furi::thread::spawn(move || {
+        let mut buf = [0; 32];
+
+        // The sender waits 2 seconds, so we don't block and get no bytes
+        assert_eq!(rx.recv(&mut buf), 0);
+
+        // The sender sends 20 bytes after two seconds, that is more than the trigger, so we continue
+        assert_eq!(rx.recv_blocking(&mut buf), 20);
+
+        // Try to receive bytes as long as the sender is alive
+        while rx.is_sender_alive() {
+            let n = rx.recv_with_timeout(&mut buf, FuriDuration::from_secs(2));
+            println!("got {} bytes: {:?}", n, buf[0..n]);
+        }
+
+        0
+    });
+
+    tx_thread.join();
+    rx_thread.join();
+
+    0
+}

crates/flipperzero/src/furi/mod.rs

@@ -5,6 +5,7 @@ pub mod kernel;
 pub mod log;
 pub mod message_queue;
 pub mod rng;
+pub mod stream_buffer;
 pub mod string;
 pub mod sync;
 pub mod thread;