From f042fd992170ee8a50a7f596f1c9cdd9600b8583 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 5 Oct 2013 15:12:35 +0300
Subject: [PATCH 1/1] Redesign uncaught exception handling to allow external
 reporters

This helps keep UI code out of the core library.  It was becoming a
problem especially on OS X where including an Objective-C wrapper around
NSAlert would have broken Builder's bootstrap.  Libmspgui will acquire
a class that will present graphical error dialogs on each platform.
---
 source/core/application.cpp         | 16 ++++++++++++++--
 source/core/application.h           |  2 --
 source/core/unix/application.cpp    | 17 -----------------
 source/core/windows/application.cpp | 16 ----------------
 source/debug/errorreporter.cpp      | 20 ++++++++++++++++++++
 source/debug/errorreporter.h        | 29 +++++++++++++++++++++++++++++
 6 files changed, 63 insertions(+), 37 deletions(-)
 delete mode 100644 source/core/unix/application.cpp
 delete mode 100644 source/core/windows/application.cpp
 create mode 100644 source/debug/errorreporter.cpp
 create mode 100644 source/debug/errorreporter.h

diff --git a/source/core/application.cpp b/source/core/application.cpp
index ebd928b..43bb023 100644
--- a/source/core/application.cpp
+++ b/source/core/application.cpp
@@ -1,4 +1,7 @@
+#include <typeinfo>
 #include <signal.h>
+#include <msp/debug/demangle.h>
+#include <msp/debug/errorreporter.h>
 #include <msp/io/print.h>
 #include "application.h"
 #include "getopt.h"
@@ -53,9 +56,18 @@ int Application::run(int argc, char **argv, void *data)
 	}
 	catch(const exception &e)
 	{
-		delete app_;
+		bool handled = false;
+		if(const Debug::ErrorReporter *er = Debug::ErrorReporter::get_current())
+			handled = er->report_uncaught_exception(e);
 
-		display_exception(e);
+		if(!handled)
+		{
+			IO::print(IO::cerr, "An uncaught exception occurred.\n");
+			IO::print(IO::cerr, "  type:   %s\n", Debug::demangle(typeid(e).name()));
+			IO::print(IO::cerr, "  what(): %s\n", e.what());
+		}
+
+		delete app_;
 
 		return 124;
 	}
diff --git a/source/core/application.h b/source/core/application.h
index 1384085..e1d3a8b 100644
--- a/source/core/application.h
+++ b/source/core/application.h
@@ -66,8 +66,6 @@ private:
 	/** Static wrapper function to call a member function of the Application
 	instance. */
 	static void sighandler_(int);
-
-	static void display_exception(const std::exception &);
 };
 
 
diff --git a/source/core/unix/application.cpp b/source/core/unix/application.cpp
deleted file mode 100644
index 7f45fbc..0000000
--- a/source/core/unix/application.cpp
+++ /dev/null
@@ -1,17 +0,0 @@
-#include <typeinfo>
-#include <msp/debug/demangle.h>
-#include <msp/io/print.h>
-#include "application.h"
-
-using namespace std;
-
-namespace Msp {
-
-void Application::display_exception(const exception &e)
-{
-	IO::print(IO::cerr, "An uncaught exception occurred.\n");
-	IO::print(IO::cerr, "  type:   %s\n", Debug::demangle(typeid(e).name()));
-	IO::print(IO::cerr, "  what(): %s\n", e.what());
-}
-
-} // namespace Msp
diff --git a/source/core/windows/application.cpp b/source/core/windows/application.cpp
deleted file mode 100644
index ed8702a..0000000
--- a/source/core/windows/application.cpp
+++ /dev/null
@@ -1,16 +0,0 @@
-#include <windows.h>
-#include <typeinfo>
-#include <msp/debug/demangle.h>
-#include "application.h"
-
-using namespace std;
-
-namespace Msp {
-
-void Application::display_exception(const exception &e)
-{
-	string msg = Debug::demangle(typeid(e).name())+":\n"+e.what();
-	MessageBoxA(0, msg.c_str(), "Uncaught exception", MB_OK|MB_ICONERROR);
-}
-
-} // namespace Msp
diff --git a/source/debug/errorreporter.cpp b/source/debug/errorreporter.cpp
new file mode 100644
index 0000000..d4d51bc
--- /dev/null
+++ b/source/debug/errorreporter.cpp
@@ -0,0 +1,20 @@
+#include "errorreporter.h"
+
+namespace Msp {
+namespace Debug {
+
+ErrorReporter *ErrorReporter::current = 0;
+
+ErrorReporter::ErrorReporter():
+	prev(current)
+{
+	current = this;
+}
+
+ErrorReporter::~ErrorReporter()
+{
+	current = prev;
+}
+
+} // namespace Debug
+} // namespace Msp
diff --git a/source/debug/errorreporter.h b/source/debug/errorreporter.h
new file mode 100644
index 0000000..b0385ff
--- /dev/null
+++ b/source/debug/errorreporter.h
@@ -0,0 +1,29 @@
+#ifndef MSP_DEBUG_ERRORREPORTER_H_
+#define MSP_DEBUG_ERRORREPORTER_H_
+
+#include <stdexcept>
+
+namespace Msp {
+namespace Debug {
+
+class ErrorReporter
+{
+private:
+	ErrorReporter *prev;
+
+	static ErrorReporter *current;
+
+protected:
+	ErrorReporter();
+public:
+	virtual ~ErrorReporter();
+
+	static const ErrorReporter *get_current() { return current; }
+
+	virtual bool report_uncaught_exception(const std::exception &) const = 0;
+};
+
+} // namespace Debug
+} // namespace Msp
+
+#endif
-- 
2.43.0