[RFC] Use raw queue elements

Arduino_Threads.h

@@ -3,18 +3,25 @@ class Shared // template definition
 {
   public:
     Shared() {
-      queue = new rtos::Queue<Shared<T>, 16>;
     }
-    operator T() const {
-      osEvent evt = queue->get();
+    operator T() {
+      osEvent evt = queue.get();
       if (evt.status == osEventMessage) {
-        Shared<T> *x = (Shared<T>*)evt.value.p;
-        return x->val;
+        T x = *((T*)evt.value.p);
+        delete (T*)evt.value.p;
+        return x;
       }
+      return val;
     }
     T& operator= (const T& other) {
+      if (queue.full()) {
+        // invokes operator T() to discard oldest element and free its memory
+        T discard = *this;
+      }
       val = other;
-      queue->put(this);
+      T* obj = new T(val);
+      queue.put(obj);
+      return (*obj);
     }
     T& peek() {
       return val;
@@ -24,7 +31,7 @@ class Shared // template definition
     }
   private:
     T val;
-    rtos::Queue<Shared<T>, 16> *queue;
+    rtos::Queue<T, 16> queue;
 };
 
 #define CONCAT2(x,y) x##y

examples/Enqueue_test/Enqueue.inot

@@ -0,0 +1,13 @@
+void setup() {
+  // put your setup code here, to run once:
+
+}
+
+int i = 0;
+
+void loop() {
+  // Continuously pump counter
+  delay(100);
+  i++;
+  counter = i;
+}

examples/Enqueue_test/Enqueue_test.ino

@@ -0,0 +1,15 @@
+void setup() {
+  // put your setup code here, to run once:
+  Serial.begin(115200);
+  while (!Serial) {}
+  Enqueue.start();
+  Serial.println("start");
+}
+
+void loop() {
+  // put your main code here, to run repeatedly:
+  delay(1000);
+  for (int i = 0; i < 10; i++) {
+    Serial.println(counter);
+  }
+}

examples/Enqueue_test/SharedVariables.h

@@ -0,0 +1 @@
+Shared<int> counter;