Separate ExceptionStore.

1 files changed, 69 insertions, 0 deletions

diff --git a/src/lib/exception_store.h b/src/lib/exception_store.h
new file mode 100644
index 000000000..d7c34c0f4
--- /dev/null
+++ b/src/lib/exception_store.h
@@ -0,0 +1,69 @@
+/*
+    Copyright (C) 2012-2014 Carl Hetherington <cth@carlh.net>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#ifndef DCPOMATIC_EXCEPTION_STORE_H
+#define DCPOMATIC_EXCEPTION_STORE_H
+
+#include <boost/exception/all.hpp>
+#include <boost/thread/mutex.hpp>
+
+/** @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::exception_ptr tmp = _exception;
+			_exception = boost::exception_ptr ();
+			boost::rethrow_exception (tmp);
+		}
+	}
+
+protected:
+
+	void store_current () {
+		boost::mutex::scoped_lock lm (_mutex);
+		_exception = boost::current_exception ();
+	}
+
+private:
+	boost::exception_ptr _exception;
+	mutable boost::mutex _mutex;
+};
+
+#endif