From 97f1f049710da905bbd1338923eb6d25125b7f15 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sun, 8 Nov 2015 20:34:20 +0000
Subject: Add exception helper

---
 libadhocutil/exception.h                 | 28 +++++++++
 libadhocutil/unittests/Jamfile.jam       | 10 ++++
 libadhocutil/unittests/testException.cpp | 97 ++++++++++++++++++++++++++++++++
 3 files changed, 135 insertions(+)
 create mode 100644 libadhocutil/exception.h
 create mode 100644 libadhocutil/unittests/testException.cpp

diff --git a/libadhocutil/exception.h b/libadhocutil/exception.h
new file mode 100644
index 0000000..a63439b
--- /dev/null
+++ b/libadhocutil/exception.h
@@ -0,0 +1,28 @@
+#ifndef ADHOCUTIL_EXCEPTION_H
+#define ADHOCUTIL_EXCEPTION_H
+
+#include <exception>
+#include <string>
+#include <boost/optional.hpp>
+
+namespace AdHoc {
+	template <typename BaseException>
+	class Exception : public BaseException {
+		public:
+			inline const char * what() const throw() override
+			{
+				if (!msg) {
+					msg = message();
+				}
+				return msg->c_str();
+			}
+
+		private:
+			virtual std::string message() const throw() = 0;
+			mutable boost::optional<std::string> msg;
+	};
+	typedef Exception<std::exception> StdException;
+}
+
+#endif
+
diff --git a/libadhocutil/unittests/Jamfile.jam b/libadhocutil/unittests/Jamfile.jam
index b4ec60a..0961f31 100644
--- a/libadhocutil/unittests/Jamfile.jam
+++ b/libadhocutil/unittests/Jamfile.jam
@@ -164,3 +164,13 @@ run
 	testFactory
 	;
 
+run
+	testException.cpp
+	: : :
+	<define>BOOST_TEST_DYN_LINK
+	<library>..//adhocutil
+	<library>boost_utf
+	:
+	testException
+	;
+
diff --git a/libadhocutil/unittests/testException.cpp b/libadhocutil/unittests/testException.cpp
new file mode 100644
index 0000000..5794468
--- /dev/null
+++ b/libadhocutil/unittests/testException.cpp
@@ -0,0 +1,97 @@
+#define BOOST_TEST_MODULE Excetion
+#include <boost/test/unit_test.hpp>
+
+#include <exception.h>
+#include <buffer.h>
+
+using namespace AdHoc;
+
+class Ex1 : public AdHoc::StdException {
+	public:
+		Ex1(const char * f, int l) : file(f), line(l) { }
+
+	private:
+		std::string message() const throw() override
+		{
+			return stringf("Something something at %s:%d", file, line);
+		}
+
+		const char * file;
+		const int line;
+};
+
+class OtherBaseException : public std::exception { };
+
+class Ex2 : public AdHoc::Exception<OtherBaseException> {
+	public:
+		Ex2(const char * f, int l) : file(f), line(l) { }
+
+	private:
+		std::string message() const throw() override
+		{
+			return stringf("Something other something at %s:%d", file, line);
+		}
+
+		const char * file;
+		const int line;
+};
+
+class Ex3 : public AdHoc::StdException {
+	private:
+		// LCOV_EXCL_START
+		std::string message() const throw() override
+		{
+			// Never called
+			std::abort();
+		}
+		// LCOV_EXCL_STOP
+};
+
+void failing1()
+{
+	throw Ex1(__PRETTY_FUNCTION__, 1);
+}
+
+void failing2()
+{
+	throw Ex2(__PRETTY_FUNCTION__, 2);
+}
+
+void failing3()
+{
+	throw Ex3();
+}
+
+BOOST_AUTO_TEST_CASE( throwCatch )
+{
+	BOOST_REQUIRE_THROW(failing1(), Ex1);
+	BOOST_REQUIRE_THROW(failing1(), std::exception);
+
+	BOOST_REQUIRE_THROW(failing2(), Ex2);
+	BOOST_REQUIRE_THROW(failing2(), OtherBaseException);
+	BOOST_REQUIRE_THROW(failing2(), std::exception);
+
+	BOOST_REQUIRE_THROW(failing3(), Ex3);
+	BOOST_REQUIRE_THROW(failing3(), std::exception);
+}
+
+BOOST_AUTO_TEST_CASE( message1 )
+{
+	try {
+		failing1();
+	}
+	catch (const std::exception & ex) {
+		BOOST_REQUIRE_EQUAL("Something something at void failing1():1", ex.what());
+	}
+}
+
+BOOST_AUTO_TEST_CASE( message2 )
+{
+	try {
+		failing2();
+	}
+	catch (const std::exception & ex) {
+		BOOST_REQUIRE_EQUAL("Something other something at void failing2():2", ex.what());
+	}
+}
+
-- 
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