1 files changed, 71 insertions, 0 deletions
diff --git a/qpid/cpp/src/qpid/sys/ExceptionHolder.h b/qpid/cpp/src/qpid/sys/ExceptionHolder.h
new file mode 100644
index 0000000000..4bc934cf75
--- /dev/null
+++ b/qpid/cpp/src/qpid/sys/ExceptionHolder.h
@@ -0,0 +1,71 @@
+#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 <boost/shared_ptr.hpp>
+
+
+namespace qpid {
+namespace sys {
+
+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() {}
+    // Use default copy & assign.
+
+    /** Take ownership of ex */
+    template <class Ex> ExceptionHolder(Ex* ex) { wrap(ex); }
+    template <class Ex> ExceptionHolder& operator=(Ex* ex) { wrap(ex); return *this; }
+
+    void raise() const { if (wrapper.get()) wrapper->raise() ; }
+    std::string what() const { return wrapper.get() ? wrapper->what() : std::string(); }
+    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(); }
+        boost::shared_ptr<Ex> exception;
+    };
+    template <class Ex> void wrap(Ex* ex) { wrapper.reset(new Wrapper<Ex>(ex)); }
+    boost::shared_ptr<Raisable> wrapper;
+};
+
+
+}} // namespace qpid::sys
+
+
+#endif  /*!QPID_EXCEPTIONHOLDER_H*/