+
+class InvalidSignerError : public StringError
+{
+public:
+ InvalidSignerError ();
+};
+
+/** @class ExceptionStore
+ * @brief A parent class for classes which have a need to catch and
+ * re-throw exceptions.
+ *
+ * This is intended for classes which run their own thread; they should do
+ * something like
+ *
+ * void my_thread ()
+ * try {
+ * // do things which might throw exceptions
+ * } catch (...) {
+ * store_current ();
+ * }
+ *
+ * and then in another thread call rethrow(). If any
+ * exception was thrown by my_thread it will be stored by
+ * store_current() and then rethrow() will re-throw it where
+ * it can be handled.
+ */
+class ExceptionStore
+{
+public:
+ void rethrow () {
+ boost::mutex::scoped_lock lm (_mutex);
+ if (_exception) {
+ boost::rethrow_exception (_exception);
+ _exception = boost::exception_ptr ();
+ }
+ }
+
+protected:
+
+ void store_current () {
+ boost::mutex::scoped_lock lm (_mutex);
+ _exception = boost::current_exception ();
+ }
+
+private:
+ boost::exception_ptr _exception;
+ mutable boost::mutex _mutex;
+};
+
+#endif