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+#ifndef QPID_EXCEPTIONHOLDER_H
+#define QPID_EXCEPTIONHOLDER_H
+
+/*
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ *
+ */
+
+#include "qpid/memory.h"
+#include <memory>
+
+namespace qpid {
+
+struct Raisable {
+ virtual ~Raisable() {};
+ virtual void raise() const=0;
+ virtual std::string what() const=0;
+};
+
+/**
+ * Holder for exceptions. Allows the thread that notices an error condition to
+ * create an exception and store it to be thrown by another thread.
+ */
+class ExceptionHolder : public Raisable {
+ public:
+ ExceptionHolder() {}
+ ExceptionHolder(ExceptionHolder& ex) : Raisable(), wrapper(ex.wrapper) {}
+ /** Take ownership of ex */
+ template <class Ex> ExceptionHolder(Ex* ex) { wrap(ex); }
+ template <class Ex> ExceptionHolder(const std::auto_ptr<Ex>& ex) { wrap(ex.release()); }
+
+ ExceptionHolder& operator=(ExceptionHolder& ex) { wrapper=ex.wrapper; return *this; }
+ template <class Ex> ExceptionHolder& operator=(Ex* ex) { wrap(ex); return *this; }
+ template <class Ex> ExceptionHolder& operator=(std::auto_ptr<Ex> ex) { wrap(ex.release()); return *this; }
+
+ void raise() const { if (wrapper.get()) wrapper->raise() ; }
+ std::string what() const { return wrapper->what(); }
+ bool empty() const { return !wrapper.get(); }
+ operator bool() const { return !empty(); }
+ void reset() { wrapper.reset(); }
+
+ private:
+ template <class Ex> struct Wrapper : public Raisable {
+ Wrapper(Ex* ptr) : exception(ptr) {}
+ void raise() const { throw *exception; }
+ std::string what() const { return exception->what(); }
+ std::auto_ptr<Ex> exception;
+ };
+ template <class Ex> void wrap(Ex* ex) { wrapper.reset(new Wrapper<Ex>(ex)); }
+ std::auto_ptr<Raisable> wrapper;
+
+};
+
+
+} // namespace qpid
+
+#endif /*!QPID_EXCEPTIONHOLDER_H*/