Add some auto baggage macros

include/baggage.h

@@ -91,5 +91,32 @@ namespace ThreadLocalBaggage {
 
 }
 
+#define BAGGAGE(b) BaggageHelpers::AutoBaggageScopeImpl __baggage__auto_baggage_(&b, __FILE__, __LINE__)
+
+
+namespace BaggageHelpers {
+
+	// Used by AutoBaggageScope macro to scope the current block to the provided baggage
+	class AutoBaggageScopeImpl {
+	private:
+		Baggage* baggageSource;
+		Baggage suspendedBaggage;
+		const char* file;
+		int line;
+	public:
+		AutoBaggageScopeImpl(Baggage* b, const char* file, int line) : file(file), line(line) {
+			baggageSource = b;
+			suspendedBaggage = ThreadLocalBaggage::Swap(*b, file, line);
+		}
+
+		~AutoBaggageScopeImpl() {
+			*baggageSource = ThreadLocalBaggage::Swap(suspendedBaggage, file, line);
+		}
+
+	};
+
+
+}
+
 
 #endif
\ No newline at end of file

src/main.cc

@@ -33,7 +33,6 @@ int main(int argc, char *argv[]) {
 	XTRACE("c", {{"key1", "value1"}, {"key2", "value2"}});
 
 	Baggage branched_baggage = BRANCH_CURRENT_BAGGAGE();
-
 	std::thread branched_thread([&branched_baggage]() {
 		SET_CURRENT_BAGGAGE(branched_baggage);	
 		XTRACE("f");
@@ -41,11 +40,35 @@ int main(int argc, char *argv[]) {
 		branched_baggage = TAKE_CURRENT_BAGGAGE();
 	});
 
+
+	// Use the auto baggage macro
+	Baggage branched_baggage2 = BRANCH_CURRENT_BAGGAGE();
+	std::thread branched_thread2([&branched_baggage2]() {
+		BAGGAGE(branched_baggage2);
+
+		XTRACE("f");
+		XTRACE("g");
+	});
+
+	Baggage inline_branched_baggage = BRANCH_CURRENT_BAGGAGE();
+
+	{
+		BAGGAGE(inline_branched_baggage);
+
+		XTRACE("hello world");
+		XTRACE("goodbyte world");
+	}
+
+
 	XTRACE("d");
 	XTRACE("e");
 
 	branched_thread.join();
+	branched_thread2.join();
+	
 	JOIN_CURRENT_BAGGAGE(branched_baggage);
+	JOIN_CURRENT_BAGGAGE(branched_baggage2);	
+	JOIN_CURRENT_BAGGAGE(inline_branched_baggage);
 
 	XTRACE("h");