Merge pull request #2414 from JomerDev/usb-logger-without-device

Adds function and macro to create usb logger without device (also fixes a logger issue)

embassy-usb-logger/src/lib.rs

@@ -6,7 +6,7 @@ use core::fmt::Write as _;
 
 use embassy_futures::join::join;
 use embassy_sync::pipe::Pipe;
-use embassy_usb::class::cdc_acm::{CdcAcmClass, State};
+use embassy_usb::class::cdc_acm::{CdcAcmClass, Receiver, Sender, State};
 use embassy_usb::driver::Driver;
 use embassy_usb::{Builder, Config};
 use log::{Metadata, Record};
@@ -37,6 +37,9 @@ impl<'d> LoggerState<'d> {
     }
 }
 
+/// The packet size used in the usb logger, to be used with `create_future_from_class`
+pub const MAX_PACKET_SIZE: u8 = 64;
+
 /// The logger handle, which contains a pipe with configurable size for buffering log messages.
 pub struct UsbLogger<const N: usize> {
     buffer: Pipe<CS, N>,
@@ -54,7 +57,6 @@ impl<const N: usize> UsbLogger<N> {
         D: Driver<'d>,
         Self: 'd,
     {
-        const MAX_PACKET_SIZE: u8 = 64;
         let mut config = Config::new(0xc0de, 0xcafe);
         config.manufacturer = Some("Embassy");
         config.product = Some("USB-serial logger");
@@ -87,22 +89,46 @@ impl<const N: usize> UsbLogger<N> {
         let mut device = builder.build();
         loop {
             let run_fut = device.run();
-            let log_fut = async {
-                let mut rx: [u8; MAX_PACKET_SIZE as usize] = [0; MAX_PACKET_SIZE as usize];
-                sender.wait_connection().await;
-                loop {
-                    let len = self.buffer.read(&mut rx[..]).await;
-                    let _ = sender.write_packet(&rx[..len]).await;
+            let class_fut = self.run_logger_class(&mut sender, &mut receiver);
+            join(run_fut, class_fut).await;
+        }
+    }
+
+    async fn run_logger_class<'d, D>(&self, sender: &mut Sender<'d, D>, receiver: &mut Receiver<'d, D>)
+    where
+        D: Driver<'d>,
+    {
+        let log_fut = async {
+            let mut rx: [u8; MAX_PACKET_SIZE as usize] = [0; MAX_PACKET_SIZE as usize];
+            sender.wait_connection().await;
+            loop {
+                let len = self.buffer.read(&mut rx[..]).await;
+                let _ = sender.write_packet(&rx[..len]).await;
+                if len as u8 == MAX_PACKET_SIZE {
+                    let _ = sender.write_packet(&[]).await;
                 }
-            };
-            let discard_fut = async {
-                let mut discard_buf: [u8; MAX_PACKET_SIZE as usize] = [0; MAX_PACKET_SIZE as usize];
-                receiver.wait_connection().await;
-                loop {
-                    let _ = receiver.read_packet(&mut discard_buf).await;
-                }
-            };
-            join(run_fut, join(log_fut, discard_fut)).await;
+            }
+        };
+        let discard_fut = async {
+            let mut discard_buf: [u8; MAX_PACKET_SIZE as usize] = [0; MAX_PACKET_SIZE as usize];
+            receiver.wait_connection().await;
+            loop {
+                let _ = receiver.read_packet(&mut discard_buf).await;
+            }
+        };
+
+        join(log_fut, discard_fut).await;
+    }
+
+    /// Creates the futures needed for the logger from a given class
+    /// This can be used in cases where the usb device is already in use for another connection
+    pub async fn create_future_from_class<'d, D>(&'d self, class: CdcAcmClass<'d, D>)
+    where
+        D: Driver<'d>,
+    {
+        let (mut sender, mut receiver) = class.split();
+        loop {
+            self.run_logger_class(&mut sender, &mut receiver).await;
         }
     }
 }
@@ -153,3 +179,27 @@ macro_rules! run {
         let _ = LOGGER.run(&mut ::embassy_usb_logger::LoggerState::new(), $p).await;
     };
 }
+
+/// Initialize the USB serial logger from a serial class and return the future to run it.
+///
+/// Arguments specify the buffer size, log level and the serial class, respectively.
+///
+/// # Usage
+///
+/// ```
+/// embassy_usb_logger::with_class!(1024, log::LevelFilter::Info, class);
+/// ```
+///
+/// # Safety
+///
+/// This macro should only be invoked only once since it is setting the global logging state of the application.
+#[macro_export]
+macro_rules! with_class {
+    ( $x:expr, $l:expr, $p:ident ) => {{
+        static LOGGER: ::embassy_usb_logger::UsbLogger<$x> = ::embassy_usb_logger::UsbLogger::new();
+        unsafe {
+            let _ = ::log::set_logger_racy(&LOGGER).map(|()| log::set_max_level_racy($l));
+        }
+        LOGGER.create_future_from_class($p)
+    }};
+}