Precommit (#1)

* first commit

* cleanup

sdv_services/data_dispatch_service/transaction.h

@@ -0,0 +1,99 @@
+#ifndef TRANSACTION_H
+#define TRANSACTION_H
+
+#include <support/interface_ptr.h>
+
+// Forward declaration
+class CDispatchService;
+class CSignal;
+
+/**
+ * @brief Transaction administration
+ * @details During creation of the transaction object, the transaction is of undefined type. The transaction takes the read or
+ * write type only after a call to the read or write function. After this, the transaction doesn't change type any more and will
+ * block calls to the functions provided for the other type (e.g. a read transaction doesn't allow a write and a write transaction
+ * doesn't allow a read).
+ * A read transaction is using the transaction ID to identify the current time of the transaction. Any data available before can
+ * be read. Any data coming after will not be transmitted. In case there is no data any more (the transaction is too old) the
+ * default value will be used.
+ * A write transaction will collect the signal values. The distribution is deferred until the transaction is finalized. During
+ * finalization, a new transaction ID is requested and the values are distributed using this ID (this is necessary so a read
+ * transaction can decide whether the values are included in a read operation).
+ * The written values are stored in a ringbuffer in the signal class. The latest position in the ring buffer contains the last
+ * distributed transaction.
+ */
+class CTransaction : public sdv::IInterfaceAccess, public sdv::IObjectDestroy
+{
+public:
+    /**
+     * @brief Constructor
+     * @param[in] rDispatchSvc Reference to the dispatch service.
+     */
+    explicit CTransaction(CDispatchService& rDispatchSvc);
+
+    // Interface map
+    BEGIN_SDV_INTERFACE_MAP()
+        SDV_INTERFACE_ENTRY(sdv::IInterfaceAccess)
+        SDV_INTERFACE_ENTRY(sdv::IObjectDestroy)
+    END_SDV_INTERFACE_MAP()
+
+    /**
+    * @brief Destroy the object. Overload of sdv::IObjectDestroy::DestroyObject.
+    */
+    virtual void DestroyObject() override;
+
+    /**
+     * @brief When called, enables the transaction as read-transaction. This would only happen when the transaction is still in
+     * undefined state.
+     * @return Returns the read-transaction ID or 0 when the transaction is not registered as read-transaction.
+     */
+    uint64_t GetReadTransactionID() const;
+
+    /**
+     * @brief When called, enables the transaction as write-transaction. This would only happen when the transaction is still in
+     * undefined state. In that case, the value will be added to the deferred signal map. Any previous value will be overwritten.
+     * @param[in] rSignal Reference to the signal class.
+     * @param[in] ranyVal Reference to the value.
+    */
+    void DeferWrite(CSignal& rSignal, sdv::any_t& ranyVal);
+
+    /**
+     * @brief Finalizes the transaction. For read transactions, nothing happens. For write transactions, a transaction ID is stored
+     * with the written signal value.
+     */
+    void FinalizeWrite();
+
+    /**
+     * @brief Set the iterator to this transaction (prevents having to search for the transaction in the transaction list).
+     * @param[in] itTransaction The iterator to store.
+     */
+    void SetIterator(std::list<CTransaction>::iterator itTransaction);
+
+    /**
+     * @brief Get the stored iterator to the transaction.
+     * @return The stored iterator.
+     */
+    std::list<CTransaction>::iterator GetIterator() const;
+
+private:
+
+    /**
+     * @brief Transaction type
+     */
+    enum class ETransactionType
+    {
+        undefined = 0,          ///< Transaction type was not defined yet.
+        read_transaction = 1,   ///< Read transaction (for TX signals).
+        write_transaction = 2,  ///< Write transaction (for RX signals and publishers).
+    };
+
+    sdv::CLifetimeCookie                m_cookie = sdv::CreateLifetimeCookie();             ///< Lifetime cookie to manage the module lifetime.
+    CDispatchService&                   m_rDispatchSvc;                                     ///< Reference to dispatch service.
+    mutable ETransactionType            m_eTransactionType = ETransactionType::undefined;   ///< Transaction type.
+    std::mutex                          m_mtxDeferredWriteSignalMap;                        ///< Deferred write signal map access.
+    std::map<CSignal*, sdv::any_t>      m_mapDeferredWriteSignalMap;                        ///< Deferred write signal map.
+    uint64_t                            m_uiReadTransactionID = 0ull;                       ///< Read transaction ID.
+    std::list<CTransaction>::iterator m_itTransaction{};                                    ///< Iterator of the transaction in the transaction list.
+};
+
+#endif // !defined TRANSACTION_H