move packet handling into its own thread

src/WorkerThread.h

@@ -0,0 +1,77 @@
+#include <Arduino.h>
+
+class Thread
+{
+  protected:
+    TaskHandle_t taskHandle = NULL;
+
+    /**
+     * set this to true to ask thread to cleanly exit asap
+     */
+    volatile bool wantExit = false;
+
+  public:
+    void start(const char *name, size_t stackSize = 1024, uint32_t priority = tskIDLE_PRIORITY);
+
+    virtual ~Thread() { vTaskDelete(taskHandle); }
+
+  protected:
+    /**
+     * The method that will be called when start is called.
+     */
+    virtual void doRun() = 0;
+
+  private:
+    static void callRun(void *_this);
+};
+
+/**
+ * This wraps threading (FreeRTOS for now) with a blocking API intended for efficiently converting onlyschool arduino loop() code.
+ *
+ * Use as a mixin base class for the classes you want to convert.
+ *
+ * https://www.freertos.org/RTOS_Task_Notification_As_Mailbox.html
+ */
+class WorkerThread : public Thread
+{
+  protected:
+    /**
+     * A method that should block execution - either waiting ona queue/mutex or a "task notification"
+     */
+    virtual void block() = 0;
+
+    virtual void loop() = 0;
+
+    /**
+     * The method that will be called when start is called.
+     */
+    virtual void doRun();
+};
+
+/**
+ * A worker thread that waits on a freertos notification
+ */
+class NotifiedWorkerThread : public WorkerThread
+{
+  public:
+    /**
+     * Notify this thread so it can run
+     */
+    void notify(uint32_t v = 0, eNotifyAction action = eNoAction);
+
+    /**
+     * Notify from an ISR
+     */
+    void notifyFromISR(BaseType_t *highPriWoken, uint32_t v = 0, eNotifyAction action = eNoAction);
+
+  protected:
+    /**
+     * The notification that was most recently used to wake the thread.  Read from loop()
+     */
+    uint32_t notification = 0;
+
+    /**
+     * A method that should block execution - either waiting ona queue/mutex or a "task notification"
+     */
+    virtual void block();
+};