From 55f95b3ac955dbd944ae430523e1f7f372a485ec Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@duempel.org>
Date: Tue, 15 Dec 2015 23:10:26 +0100
Subject: [PATCH] Log: C++ exception support

---
 src/Log.cxx | 36 ++++++++++++++++++++++++++++++++++++
 src/Log.hxx | 10 ++++++++++
 2 files changed, 46 insertions(+)

diff --git a/src/Log.cxx b/src/Log.cxx
index 585e51f7c..65d3be824 100644
--- a/src/Log.cxx
+++ b/src/Log.cxx
@@ -20,12 +20,18 @@
 #include "config.h"
 #include "LogV.hxx"
 #include "util/Error.hxx"
+#include "util/Domain.hxx"
+
+#include <exception>
 
 #include <assert.h>
 #include <stdio.h>
 #include <string.h>
 #include <errno.h>
 
+/** Domain for std::exception */
+static constexpr Domain exception_domain("exception");
+
 void
 LogFormatV(const Domain &domain, LogLevel level, const char *fmt, va_list ap)
 {
@@ -88,6 +94,36 @@ FormatError(const Domain &domain, const char *fmt, ...)
 	va_end(ap);
 }
 
+void
+LogError(const std::exception &e)
+{
+	Log(exception_domain, LogLevel::ERROR, e.what());
+
+	try {
+		std::rethrow_if_nested(e);
+	} catch (const std::exception &nested) {
+		LogError(nested, "nested");
+	} catch (...) {
+		Log(exception_domain, LogLevel::ERROR,
+		    "Unrecognized nested exception");
+	}
+}
+
+void
+LogError(const std::exception &e, const char *msg)
+{
+	FormatError(exception_domain, "%s: %s", msg, e.what());
+
+	try {
+		std::rethrow_if_nested(e);
+	} catch (const std::exception &nested) {
+		LogError(nested);
+	} catch (...) {
+		Log(exception_domain, LogLevel::ERROR,
+		    "Unrecognized nested exception");
+	}
+}
+
 void
 LogError(const Error &error)
 {
diff --git a/src/Log.hxx b/src/Log.hxx
index 684d5c394..f6474ff1a 100644
--- a/src/Log.hxx
+++ b/src/Log.hxx
@@ -23,6 +23,10 @@
 #include "LogLevel.hxx"
 #include "Compiler.h"
 
+namespace std {
+	class exception;
+}
+
 class Error;
 class Domain;
 
@@ -79,6 +83,12 @@ LogError(const Domain &domain, const char *msg)
 	Log(domain, LogLevel::ERROR, msg);
 }
 
+void
+LogError(const std::exception &e);
+
+void
+LogError(const std::exception &e, const char *msg);
+
 gcc_printf(2,3)
 void
 FormatError(const Domain &domain, const char *fmt, ...);