fsfw/storagemanager/ConstStorageAccessor.h

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2020-06-23 10:58:48 +02:00
#ifndef FRAMEWORK_STORAGEMANAGER_CONSTSTORAGEACCESSOR_H_
#define FRAMEWORK_STORAGEMANAGER_CONSTSTORAGEACCESSOR_H_
#include <framework/storagemanager/storeAddress.h>
#include <framework/returnvalues/HasReturnvaluesIF.h>
#include <cstddef>
class StorageManagerIF;
/**
* @brief Helper classes to facilitate safe access to storages which is also
* conforming to RAII principles
* @details
* Accessor class which can be returned by pool manager or passed and set by
* pool managers to have safe access to the pool resources.
*
* These helper can be used together with the StorageManager classes to manage
* access to a storage. It can take care of thread-safety while also providing
* mechanisms to automatically clear storage data.
*/
class ConstStorageAccessor {
//! StorageManager classes have exclusive access to private variables.
template<uint8_t NUMBER_OF_POOLS>
friend class PoolManager;
template<uint8_t NUMBER_OF_POOLS>
friend class LocalPool;
public:
/**
* @brief Simple constructor which takes the store ID of the storage
* entry to access.
* @param storeId
*/
ConstStorageAccessor(store_address_t storeId);
ConstStorageAccessor(store_address_t storeId, StorageManagerIF* store);
/**
* @brief The destructor in default configuration takes care of
* deleting the accessed pool entry and unlocking the mutex
*/
virtual ~ConstStorageAccessor();
/**
* @brief Returns a pointer to the read-only data
* @return
*/
const uint8_t* data() const;
/**
* @brief Copies the read-only data to the supplied pointer
* @param pointer
*/
virtual ReturnValue_t getDataCopy(uint8_t *pointer, size_t maxSize);
/**
* @brief Calling this will prevent the Accessor from deleting the data
* when the destructor is called.
*/
void release();
/**
* Get the size of the data
* @return
*/
size_t size() const;
/**
* Get the storage ID.
* @return
*/
store_address_t getId() const;
void print() const;
/**
* @brief Move ctor and move assignment allow returning accessors as
* a returnvalue. They prevent resource being free prematurely.
* Refer to: https://github.com/MicrosoftDocs/cpp-docs/blob/master/docs/cpp/
* move-constructors-and-move-assignment-operators-cpp.md
* @param
* @return
*/
ConstStorageAccessor& operator= (ConstStorageAccessor&&);
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ConstStorageAccessor(ConstStorageAccessor&&);
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//! The copy ctor and copy assignemnt should be deleted implicitely
//! according to https://foonathan.net/2019/02/special-member-functions/
//! but I still deleted them to make it more explicit. (remember rule of 5).
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ConstStorageAccessor& operator=(const ConstStorageAccessor&) = delete;
ConstStorageAccessor(const ConstStorageAccessor&) = delete;
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protected:
const uint8_t* constDataPointer = nullptr;
store_address_t storeId;
size_t size_ = 0;
//! Managing pool, has to assign itself.
StorageManagerIF* store = nullptr;
bool deleteData = true;
enum class AccessState {
UNINIT,
ASSIGNED
};
//! Internal state for safety reasons.
AccessState internalState = AccessState::UNINIT;
/**
* Used by the pool manager instances to assign themselves to the
* accessor. This is necessary to delete the data when the acessor
* exits the scope ! The internal state will be considered read
* when this function is called, so take care all data is set properly as
* well.
* @param
*/
void assignStore(StorageManagerIF*);
};
#endif /* FRAMEWORK_STORAGEMANAGER_CONSTSTORAGEACCESSOR_H_ */