fix: allow returning type from metrics

Author: lulf

host/src/channel_manager.rs

@@ -758,10 +758,10 @@ impl<'d> ChannelManager<'d> {
     }
 
     #[cfg(feature = "channel-metrics")]
-    pub(crate) fn metrics<F: FnOnce(&Metrics)>(&self, index: ChannelIndex, f: F) {
+    pub(crate) fn metrics<F: FnOnce(&Metrics) -> R, R>(&self, index: ChannelIndex, f: F) -> R {
         self.with_mut(|state| {
             let state = &state.channels[index.0 as usize];
-            f(&state.metrics);
+            f(&state.metrics)
         })
     }
 }

host/src/connection.rs

@@ -334,8 +334,8 @@ impl<'stack> Connection<'stack> {
 
     /// Read metrics for this connection
     #[cfg(feature = "connection-metrics")]
-    pub fn metrics<F: FnOnce(&ConnectionMetrics)>(&self, f: F) {
-        self.manager.metrics(self.index, f);
+    pub fn metrics<F: FnOnce(&ConnectionMetrics) -> R, R>(&self, f: F) -> R {
+        self.manager.metrics(self.index, f)
     }
 
     /// The RSSI value for this connection.

host/src/connection_manager.rs

@@ -711,10 +711,10 @@ impl<'d> ConnectionManager<'d> {
     }
 
     #[cfg(feature = "connection-metrics")]
-    pub(crate) fn metrics<F: FnOnce(&Metrics)>(&self, index: u8, f: F) {
+    pub(crate) fn metrics<F: FnOnce(&Metrics) -> R, R>(&self, index: u8, f: F) -> R {
         self.with_mut(|state| {
             let state = &state.connections[index as usize];
-            f(&state.metrics);
+            f(&state.metrics)
         })
     }
 }

host/src/host.rs

@@ -519,9 +519,9 @@ where
     }
 
     /// Read current host metrics
-    pub(crate) fn metrics<F: FnOnce(&HostMetrics)>(&self, f: F) {
+    pub(crate) fn metrics<F: FnOnce(&HostMetrics) -> R, R>(&self, f: F) -> R {
         let m = self.metrics.borrow();
-        f(&m);
+        f(&m)
     }
 
     /// Log status information of the host

host/src/l2cap.rs

@@ -150,8 +150,8 @@ impl<'d> L2capChannel<'d> {
 
     /// Read metrics of the l2cap channel.
     #[cfg(feature = "channel-metrics")]
-    pub fn metrics<F: FnOnce(&ChannelMetrics)>(&self, f: F) {
-        self.manager.metrics(self.index, f);
+    pub fn metrics<F: FnOnce(&ChannelMetrics) -> R, R>(&self, f: F) -> R {
+        self.manager.metrics(self.index, f)
     }
 
     /// Await an incoming connection request matching the list of PSM.
@@ -250,8 +250,8 @@ impl<'d> L2capChannelReader<'d> {
 
     /// Read metrics of the l2cap channel.
     #[cfg(feature = "channel-metrics")]
-    pub fn metrics<F: FnOnce(&ChannelMetrics)>(&self, f: F) {
-        self.manager.metrics(self.index, f);
+    pub fn metrics<F: FnOnce(&ChannelMetrics) -> R, R>(&self, f: F) -> R {
+        self.manager.metrics(self.index, f)
     }
 }
 
@@ -300,7 +300,7 @@ impl<'d> L2capChannelWriter<'d> {
 
     /// Read metrics of the l2cap channel.
     #[cfg(feature = "channel-metrics")]
-    pub fn metrics<F: FnOnce(&ChannelMetrics)>(&self, f: F) {
-        self.manager.metrics(self.index, f);
+    pub fn metrics<F: FnOnce(&ChannelMetrics) -> R, R>(&self, f: F) -> R {
+        self.manager.metrics(self.index, f)
     }
 }

host/src/lib.rs

@@ -556,8 +556,8 @@ impl<'stack, C: Controller> Stack<'stack, C> {
     }
 
     /// Read current host metrics
-    pub fn metrics<F: FnOnce(&HostMetrics)>(&self, f: F) {
-        self.host.metrics(f);
+    pub fn metrics<F: FnOnce(&HostMetrics) -> R, R>(&self, f: F) -> R {
+        self.host.metrics(f)
     }
 
     /// Log status information of the host