(in-package :rdb)

 (define-condition rdb-error (error)

   ((message :initarg :message

             :reader rdb-error-message))

   (:documentation "Error signaled by the RDB system"))

 (define-condition rocksdb-error (rdb-error)

   ((db :initarg :db :reader rdb-error-db))

   (:documentation "Error signaled by RocksDB subsystem"))

 (defmethod print-object ((obj rdb-error) stream)

   (print-unreadable-object (obj stream :type t :identity t)

     (format stream "~A" (rdb-error-message obj))))

 (define-condition open-db-error (rocksdb-error)

   ()

   (:documentation "Error signaled while opening a database"))

 (define-condition destroy-db-error (rocksdb-error)

   ()

   (:documentation "Error signaled while destroying a database"))

 (define-condition cf-error (rocksdb-error)

   ((cf :initarg :cf :reader rdb-error-cf)))

 (define-condition put-kv-error (rdb-error)

   ((kv :initarg :kv :reader rdb-error-kv))

   (:documentation "Error signaled while processing a PUT-KV request"))

 (define-condition get-kv-error (rdb-error)

   ((key :initarg :key :reader key))

   (:documentation "Error signaled while processing a GET-KV request"))

 (defun handle-errptr (errptr &optional errtyp params)

   "Handle ERRPTR, a ROCKSDB-ERRPTR type which is a pointer to NULL,

 indicating a success or a pointer to a C-STRING.

 ERRTYP if present must be a condition which sub-classes RDB-ERROR. If

 an error is detected, the resulting string from ERRPTR and the

 additional PARAMS will be used to signal a lisp error condition."

   ;; if NULL, return nil

   (unless (null-alien errptr)

     (apply #'signal (or errtyp 'rdb-error)

            (nconc (list :message errptr) params))))

 (defmacro with-errptr ((e &optional errtyp params) &body body)

   `(with-alien ((,e rocksdb-errptr nil))

      (unwind-protect 

           (handler-bind ((sb-sys:memory-fault-error 

                            (lambda (condition)

                              (error 'rdb-error

                                     :message

                                     (format nil

                          (error 

                            (lambda (condition)

                              (error 'rdb-error 

                                     :message 

                                     (format nil 

                                             condition)))))

             (progn ,@body))

        (handle-errptr ,e ,errtyp ,params))))