src/api/cpp/include/gmxapi/status.h

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  35
  36 #ifndef GMXAPI_STATUS_H
  37 #define GMXAPI_STATUS_H
  38 /*! \file
  39  * \brief Declare Status class for API operations with no other results.
  40  *
  41  * \author M. Eric Irrgang <ericirrgang@gmail.com>
  42  * \ingroup gmxapi
  43  */
  44
  45 #include <memory>
  46
  47 namespace gmxapi
  48 {
  49 /*! \brief Trivial API operation return value.
  50  *
  51  * Returned by some API operations when a richer return value type does not
  52  * exist.
  53  *
  54  * \cond internal
  55  * In general, API operations should return an object and not to allow
  56  * unsuccessful operations to go undetected. In some cases, there is either no
  57  * obvious result object or the API needs a placeholder for a more elaborate
  58  * result to be implemented in a future version. This class allows a return
  59  * value and potential proxy object as a fall-back where no other option exists.
  60  * \endcond
  61  *
  62  * \ingroup gmxapi
  63  */
  64 class Status final
  65 {
  66     public:
  67         /*!
  68          * \brief Status is "unsuccessful" until set otherwise.
  69          *
  70          * \internal
  71          * Default constructor can be used for convenience when preparing the
  72          * return value for an operation that should be assumed unsuccessful
  73          * until proven otherwise.
  74          */
  75         Status();
  76         /*!
  77          * \brief Can be copy-initialized
  78          *
  79          * \param status
  80          */
  81         Status(const Status &status);
  82         /*!
  83          * \brief Can be moved.
  84          */
  85         Status(Status &&) noexcept;
  86         /*!
  87          * \brief Can be copy-assigned.
  88          *
  89          * \param status
  90          * \return reference to lhs.
  91          */
  92         Status &operator=(const Status &status);
  93         /*!
  94          * \brief Transfer ownership by move assignment.
  95          *
  96          * \param status
  97          * \return reference to lhs
  98          */
  99         Status &operator=(Status &&status) noexcept;
 100         /*!
 101          * \brief Set success status from boolean.
 102          *
 103          * \param success true to indicate successful operation.
 104          * \return reference to lhs
 105          */
 106         Status &operator=(bool success);
 107
 108         /*!
 109          * \brief Initialize with success set true or false.
 110          *
 111          * \param success
 112          */
 113         explicit Status(bool success);
 114
 115         /*!
 116          * \brief Clean up resources.
 117          *
 118          * Note non-virtual destructor. This class is not heritable.
 119          */
 120         ~Status();
 121
 122         /*!
 123          * \brief Check success status.
 124          *
 125          * Forces evaluation of any pending computation. The operation that
 126          * returned the Status object is guaranteed to complete, successfully
 127          * or unsuccessfully, before this function returns.
 128          *
 129          * \return true if the operation described was successful.
 130          *
 131          * \internal
 132          * Unsuccessful operations should have more useful information associated
 133          * than just a boolean. Future versions should behave more like a
 134          * `gmx::future<gmx::expected<T>>`, but this functionality is not yet
 135          * available.
 136          */
 137         bool success() const;
 138     private:
 139         //! \cond
 140         class Impl;
 141         std::unique_ptr<Impl> impl_;
 142         //! \endcond
 143 };
 144
 145 }      // end namespace gmxapi
 146
 147 #endif //GMXAPI_STATUS_H