Squash of branch setup

main/common/semaphore_guard.h

@@ -0,0 +1,49 @@
+#pragma once
+#include "freertos/semphr.h"
+#include "freertos/portmacro.h"
+#include "esp_log.h"
+
+struct SemaphoreGuard {
+public:
+
+  SemaphoreGuard(SemaphoreHandle_t semaphore) : semaphore(semaphore) { }
+
+  portBASE_TYPE take(TickType_t ticks_to_wait = portMAX_DELAY) {
+    if (this->semaphore == nullptr) {
+      ESP_LOGE("SemaphoreGuard", "Attempted to take a null semaphore");
+      return pdFALSE;
+    }
+    portBASE_TYPE result = xSemaphoreTake(this->semaphore, ticks_to_wait);
+    taken = (result == pdTRUE);
+    return result;
+  }
+
+  ~SemaphoreGuard() {
+    if (taken) {
+      xSemaphoreGive(this->semaphore);
+    }
+  }
+
+  // allow move semantics
+  SemaphoreGuard(SemaphoreGuard&& other) noexcept
+    : semaphore(other.semaphore), taken(other.taken) {
+    other.taken = false;
+  }
+  SemaphoreGuard& operator=(SemaphoreGuard&& other) noexcept {
+    if (this != &other) {
+      // move from other
+      taken = other.taken;
+      other.taken = false;
+      semaphore = other.semaphore;
+      other.semaphore = nullptr;
+    }
+    return *this;
+  }
+
+private:
+  // prevent copying
+  SemaphoreGuard(const SemaphoreGuard&) = delete;
+  SemaphoreGuard& operator=(const SemaphoreGuard&) = delete;
+  SemaphoreHandle_t semaphore = nullptr;
+  bool taken = false;
+};