initial checkin

firmware/src/semaphore_guard.h

@@ -0,0 +1,33 @@
+/*
+   Copyright 2020 Scott Bezek and the splitflap contributors
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+#pragma once
+
+#include <Arduino.h>
+
+class SemaphoreGuard {
+    public:
+        SemaphoreGuard(SemaphoreHandle_t handle) : handle_{handle} {
+            xSemaphoreTake(handle_, portMAX_DELAY);
+        }
+        ~SemaphoreGuard() {
+            xSemaphoreGive(handle_);
+        }
+        SemaphoreGuard(SemaphoreGuard const&)=delete;
+        SemaphoreGuard& operator=(SemaphoreGuard const&)=delete;
+
+    private:
+        SemaphoreHandle_t handle_;
+};