[CallerEnvironment] Add a new OWNER caller environment

The OWNER caller environment can be used when the executed algorithm
should be different if the current worker owns the objects it touches.
For example a worker reaping completions on a foreign IoContext may
use the EMPER callerEnvironment and the worker of the IoContext OWNER.

Also implement the stream operator to print caller environments.

emper/CallerEnvironment.cpp

+// SPDX-License-Identifier: LGPL-3.0-or-later
+// Copyright © 2021 Florian Fischer
+#include "CallerEnvironment.hpp"
+
+#include <iostream>
+
+#include "Common.hpp"
+
+auto operator<<(std::ostream& os, const CallerEnvironment& callerEnvironment) -> std::ostream& {
+	switch (callerEnvironment) {
+		case OWNER:
+			return os << "OWNER";
+		case EMPER:
+			return os << "EMPER";
+		case ANYWHERE:
+			return os << "ANYWHERE";
+		default:
+			DIE_MSG("Unknown CallerEnvironment");
+	}
+}

emper/CallerEnvironment.hpp

 // SPDX-License-Identifier: LGPL-3.0-or-later
-// Copyright © 2020 Florian Schmaus
+// Copyright © 2020-2021 Florian Schmaus, Florian Fischer
 #pragma once
 
+#include <iostream>
+
+/*! Enum representing the different environments where code can be executed */
 enum CallerEnvironment {
-	EMPER,
-	ANYWHERE,
+	OWNER,		/*!< indicate code executed by the worker owning the object */
+	EMPER,		/*!< indicate code executed by any worker */
+	ANYWHERE, /*!< indicate code executed outside of any worker */
 };
+
+auto operator<<(std::ostream& os, const CallerEnvironment& callerEnvironment) -> std::ostream&;

emper/meson.build

@@ -13,6 +13,7 @@ nasm_gen = generator(nasm,
 emper_asm_objects = nasm_gen.process(emper_asm_sources)
 
 emper_cpp_sources = [
+  'CallerEnvironment.cpp',
   'Runtime.cpp',
   'Emper.cpp',
   'Fiber.cpp',