protected_struct.h

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#pragma once
 
#include <freertos/FreeRTOS.h>
#include "helpers/halt_execution.h"
#include "lib/logger/logger.h"

template <typename struct_type>
class protected_struct {
private:
    static constexpr const char* TAG = "protected_struct";
 
    struct_type data;
    mutable SemaphoreHandle_t mutex;
 
    class mutex_lock {
    public:
        protected_struct* parent;
 
        explicit mutex_lock(const protected_struct* parent) :
            parent(const_cast<protected_struct*>(parent))
        {
            if (xSemaphoreGetMutexHolder(parent->mutex) == xTaskGetCurrentTaskHandle()) {
                LOGE("Mutex deadlock detected, aborting");
                halt_execution();
            }
 
            xSemaphoreTake(parent->mutex, portMAX_DELAY);
        }
 
        ~mutex_lock() {
            unlock();
        }

        void unlock() {
            if (parent != nullptr) {
                xSemaphoreGive(parent->mutex);
                parent = nullptr;
            }
        }
 
        struct_type* operator->() {
            return parent != nullptr ? &parent->data : nullptr;
        }
 
        operator struct_type&() {
            return parent->data;
        }
    };
 
public:
    explicit protected_struct() : mutex(xSemaphoreCreateMutex()) {
        if (mutex == nullptr) {
            LOGE("Mutex creation failed");
            halt_execution();
        }
    }
    ~protected_struct() {
        if (mutex != nullptr) {
            vSemaphoreDelete(mutex);
        }
    }
 
    protected_struct(const protected_struct&) = delete;
    protected_struct& operator=(const protected_struct&) = delete;

    mutex_lock operator->() const {
        return mutex_lock(this);
    }

    mutex_lock lock() const {
        return mutex_lock(this);
    }
};