spinOnce(), fixes #31

libuavcan/src/node/uc_scheduler.cpp

@@ -159,7 +159,8 @@ int Scheduler::spin(MonotonicTime deadline)
         UAVCAN_ASSERT(0);
         return -ErrRecursiveCall;
     }
-    inside_spin_ = true;
+    InsideSpinSetter iss(*this);
+    UAVCAN_ASSERT(inside_spin_);
 
     int retval = 0;
     while (true)
@@ -179,7 +180,28 @@ int Scheduler::spin(MonotonicTime deadline)
         }
     }
 
-    inside_spin_ = false;
+    return retval;
+}
+
+int Scheduler::spinOnce()
+{
+    if (inside_spin_)  // Preventing recursive calls
+    {
+        UAVCAN_ASSERT(0);
+        return -ErrRecursiveCall;
+    }
+    InsideSpinSetter iss(*this);
+    UAVCAN_ASSERT(inside_spin_);
+
+    const int retval = dispatcher_.spinOnce();
+    if (retval < 0)
+    {
+        return retval;
+    }
+
+    const MonotonicTime ts = deadline_scheduler_.pollAndGetMonotonicTime(getSystemClock());
+    pollCleanup(ts, unsigned(retval));
+
     return retval;
 }
 

libuavcan/src/transport/uc_dispatcher.cpp

@@ -229,6 +229,40 @@ int Dispatcher::spin(MonotonicTime deadline)
     return num_frames_processed;
 }
 
+int Dispatcher::spinOnce()
+{
+    int num_frames_processed = 0;
+
+    while (true)
+    {
+        CanIOFlags flags = 0;
+        CanRxFrame frame;
+        const int res = canio_.receive(frame, MonotonicTime(), flags);
+        if (res < 0)
+        {
+            return res;
+        }
+        else if (res > 0)
+        {
+            if (flags & CanIOFlagLoopback)
+            {
+                handleLoopbackFrame(frame);
+            }
+            else
+            {
+                num_frames_processed++;
+                handleFrame(frame);
+            }
+        }
+        else
+        {
+            break;      // No frames left
+        }
+    }
+
+    return num_frames_processed;
+}
+
 int Dispatcher::send(const Frame& frame, MonotonicTime tx_deadline, MonotonicTime blocking_deadline,
                      CanTxQueue::Qos qos, CanIOFlags flags, uint8_t iface_mask)
 {