DEV-41354 convert llerror tut test into a llcommon integration test

1 files changed, 767 insertions, 0 deletions

diff --git a/indra/llcommon/tests/llerror_test.cpp b/indra/llcommon/tests/llerror_test.cpp
new file mode 100644
index 0000000000..930047e164
--- /dev/null
+++ b/indra/llcommon/tests/llerror_test.cpp
@@ -0,0 +1,767 @@
+/** 
+ * @file llerror_tut.cpp
+ * @date   December 2006
+ * @brief error unit tests
+ *
+ * $LicenseInfo:firstyear=2006&license=viewergpl$
+ * 
+ * Copyright (c) 2006-2009, Linden Research, Inc.
+ * 
+ * Second Life Viewer Source Code
+ * The source code in this file ("Source Code") is provided by Linden Lab
+ * to you under the terms of the GNU General Public License, version 2.0
+ * ("GPL"), unless you have obtained a separate licensing agreement
+ * ("Other License"), formally executed by you and Linden Lab.  Terms of
+ * the GPL can be found in doc/GPL-license.txt in this distribution, or
+ * online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
+ * 
+ * There are special exceptions to the terms and conditions of the GPL as
+ * it is applied to this Source Code. View the full text of the exception
+ * in the file doc/FLOSS-exception.txt in this software distribution, or
+ * online at
+ * http://secondlifegrid.net/programs/open_source/licensing/flossexception
+ * 
+ * By copying, modifying or distributing this software, you acknowledge
+ * that you have read and understood your obligations described above,
+ * and agree to abide by those obligations.
+ * 
+ * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
+ * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
+ * COMPLETENESS OR PERFORMANCE.
+ * $/LicenseInfo$
+ */
+
+#include "linden_common.h"
+#include "../llerror.h"
+
+namespace
+{
+	void test_that_error_h_includes_enough_things_to_compile_a_message()
+	{
+		llinfos << "!" << llendl;
+	}
+}
+
+#include "../test/lltut.h"
+
+#include <vector>
+
+#include "../llerrorcontrol.h"
+#include "../llsd.h"
+
+namespace
+{
+	static bool fatalWasCalled;
+	void fatalCall(const std::string&) { fatalWasCalled = true; }
+	
+	class TestRecorder : public LLError::Recorder
+	{
+	public:
+		TestRecorder() : mWantsTime(false) { }
+		~TestRecorder() { LLError::removeRecorder(this); }
+		
+		void recordMessage(LLError::ELevel level,
+							const std::string& message)
+		{
+			mMessages.push_back(message);
+		}
+		
+		int countMessages()			{ return (int) mMessages.size(); }
+		void clearMessages()		{ mMessages.clear(); }
+		
+		void setWantsTime(bool t)	{ mWantsTime = t; }
+		bool wantsTime()			{ return mWantsTime; }
+
+		std::string message(int n)
+		{
+			std::ostringstream test_name;
+			test_name << "testing message " << n << ", not enough messages";
+
+			tut::ensure(test_name.str(), n < countMessages());
+			return mMessages[n];
+		}
+		
+	private:
+		typedef std::vector<std::string> MessageVector;
+		MessageVector mMessages;
+		
+		bool mWantsTime;
+	};
+}
+	
+namespace tut
+{
+	struct ErrorTestData
+	{
+		TestRecorder mRecorder;
+		LLError::Settings* mPriorErrorSettings;
+		
+		ErrorTestData()
+		{
+			fatalWasCalled = false;
+			
+			mPriorErrorSettings = LLError::saveAndResetSettings();
+			LLError::setDefaultLevel(LLError::LEVEL_DEBUG);
+			LLError::setFatalFunction(fatalCall);
+			LLError::addRecorder(&mRecorder);
+		}
+		
+		~ErrorTestData()
+		{
+			LLError::removeRecorder(&mRecorder);
+			LLError::restoreSettings(mPriorErrorSettings);
+		}
+		
+		void ensure_message_count(int expectedCount)
+		{
+			ensure_equals("message count", mRecorder.countMessages(), expectedCount);
+		}
+
+		void ensure_message_contains(int n, const std::string& expectedText)
+		{
+			std::ostringstream test_name;
+			test_name << "testing message " << n;
+
+			ensure_contains(test_name.str(), mRecorder.message(n), expectedText);
+		}
+
+		void ensure_message_does_not_contain(int n, const std::string& expectedText)
+		{
+			std::ostringstream test_name;
+			test_name << "testing message " << n;
+
+			ensure_does_not_contain(test_name.str(), mRecorder.message(n), expectedText);
+		}
+	};
+	
+	typedef test_group<ErrorTestData>	ErrorTestGroup;
+	typedef ErrorTestGroup::object		ErrorTestObject;
+	
+	ErrorTestGroup errorTestGroup("error");
+	
+	template<> template<>
+	void ErrorTestObject::test<1>()
+		// basic test of output
+	{
+		llinfos << "test" << llendl;
+		llinfos << "bob" << llendl;
+		
+		ensure_message_contains(0, "test");
+		ensure_message_contains(1, "bob");
+	}
+}
+
+namespace
+{
+	void writeSome()
+	{
+		lldebugs << "one" << llendl;
+		llinfos << "two" << llendl;
+		llwarns << "three" << llendl;
+		llerrs << "four" << llendl;
+			// fatal messages write out and addtional "error" message
+	}
+};
+
+namespace tut
+{	
+	template<> template<>
+	void ErrorTestObject::test<2>()
+		// messages are filtered based on default level
+	{
+		LLError::setDefaultLevel(LLError::LEVEL_DEBUG);
+		writeSome();
+		ensure_message_contains(0, "one");
+		ensure_message_contains(1, "two");
+		ensure_message_contains(2, "three");
+		ensure_message_contains(3, "error");
+		ensure_message_contains(4, "four");
+		ensure_message_count(5);
+	
+		LLError::setDefaultLevel(LLError::LEVEL_INFO);
+		writeSome();
+		ensure_message_contains(5, "two");
+		ensure_message_contains(6, "three");
+		ensure_message_contains(7, "error");
+		ensure_message_contains(8, "four");
+		ensure_message_count(9);
+		
+		LLError::setDefaultLevel(LLError::LEVEL_WARN);
+		writeSome();
+		ensure_message_contains(9, "three");
+		ensure_message_contains(10, "error");
+		ensure_message_contains(11, "four");
+		ensure_message_count(12);
+		
+		LLError::setDefaultLevel(LLError::LEVEL_ERROR);
+		writeSome();
+		ensure_message_contains(12, "error");
+		ensure_message_contains(13, "four");
+		ensure_message_count(14);
+		
+		LLError::setDefaultLevel(LLError::LEVEL_NONE);
+		writeSome();
+		ensure_message_count(14);
+	}
+
+	template<> template<>
+	void ErrorTestObject::test<3>()
+		// error type string in output
+	{
+		writeSome();
+		ensure_message_contains(0, "DEBUG: ");
+		ensure_message_contains(1, "INFO: ");
+		ensure_message_contains(2, "WARNING: ");
+		ensure_message_does_not_contain(3, "ERROR");
+		ensure_message_contains(4, "ERROR: ");
+		ensure_message_count(5);
+	}
+
+	template<> template<>
+	void ErrorTestObject::test<4>()
+		// file abbreviation
+	{
+		std::string thisFile = __FILE__;
+		std::string abbreviateFile = LLError::abbreviateFile(thisFile);
+		
+		ensure_ends_with("file name abbreviation",
+			abbreviateFile,
+			"llcommon/tests/llerror_test.cpp"
+			);
+		ensure_does_not_contain("file name abbreviation",
+			abbreviateFile, "indra");
+			
+		std::string someFile =
+#if LL_WINDOWS
+			"C:/amy/bob/cam.cpp"
+#else
+			"/amy/bob/cam.cpp"
+#endif
+			;
+		std::string someAbbreviation = LLError::abbreviateFile(someFile);
+		
+		ensure_equals("non-indra file abbreviation",
+			someAbbreviation, someFile);
+	}
+}
+	
+namespace
+{
+	std::string locationString(int line)
+	{
+		std::ostringstream location;
+		location << LLError::abbreviateFile(__FILE__)
+				 << "(" << line << ") : ";
+				 
+		return location.str();
+	}
+	
+	std::string writeReturningLocation()
+	{
+		llinfos << "apple" << llendl;	int this_line = __LINE__;
+		return locationString(this_line);
+	}
+	
+	std::string writeReturningLocationAndFunction()
+	{
+		llinfos << "apple" << llendl;	int this_line = __LINE__;
+		return locationString(this_line) + __FUNCTION__;
+	}
+	
+	std::string errorReturningLocation()
+	{
+		llerrs << "die" << llendl;	int this_line = __LINE__;
+		return locationString(this_line);
+	}
+}
+
+namespace tut
+{	
+	template<> template<>
+	void ErrorTestObject::test<5>()
+		// file and line information in log messages
+	{
+		std::string location = writeReturningLocation();
+			// expecting default to not print location information
+		
+		LLError::setPrintLocation(true);
+		writeReturningLocation();
+		
+		LLError::setPrintLocation(false);
+		writeReturningLocation();
+		
+		ensure_message_does_not_contain(0, location);
+		ensure_message_contains(1, location);
+		ensure_message_does_not_contain(2, location);
+	}
+}
+
+/* The following helper functions and class members all log a simple message
+	from some particular function scope.  Each function takes a bool argument
+	that indicates if it should log its own name or not (in the manner that
+	existing log messages often do.)  The functions all return their C++
+	name so that test can be substantial mechanized.
+ */
+ 
+std::string logFromGlobal(bool id)
+{
+	llinfos << (id ? "logFromGlobal: " : "") << "hi" << llendl;
+	return "logFromGlobal";
+}
+
+static std::string logFromStatic(bool id)
+{
+	llinfos << (id ? "logFromStatic: " : "") << "hi" << llendl;
+	return "logFromStatic";
+}
+
+namespace
+{
+	std::string logFromAnon(bool id)
+	{
+		llinfos << (id ? "logFromAnon: " : "") << "hi" << llendl;
+		return "logFromAnon";
+	}
+}
+
+namespace Foo {
+	std::string logFromNamespace(bool id)
+	{
+		llinfos << (id ? "Foo::logFromNamespace: " : "") << "hi" << llendl;
+		//return "Foo::logFromNamespace";
+			// there is no standard way to get the namespace name, hence
+			// we won't be testing for it
+		return "logFromNamespace";
+	}
+}
+
+namespace
+{
+	class ClassWithNoLogType {
+	public:
+		std::string logFromMember(bool id)
+		{
+			llinfos << (id ? "ClassWithNoLogType::logFromMember: " : "") << "hi" << llendl;
+			return "ClassWithNoLogType::logFromMember";
+		}
+		static std::string logFromStatic(bool id)
+		{
+			llinfos << (id ? "ClassWithNoLogType::logFromStatic: " : "") << "hi" << llendl;
+			return "ClassWithNoLogType::logFromStatic";
+		}
+	};
+	
+	class ClassWithLogType {
+		LOG_CLASS(ClassWithLogType);
+	public:
+		std::string logFromMember(bool id)
+		{
+			llinfos << (id ? "ClassWithLogType::logFromMember: " : "") << "hi" << llendl;
+			return "ClassWithLogType::logFromMember";
+		}
+		static std::string logFromStatic(bool id)
+		{
+			llinfos << (id ? "ClassWithLogType::logFromStatic: " : "") << "hi" << llendl;
+			return "ClassWithLogType::logFromStatic";
+		}
+	};
+	
+	std::string logFromNamespace(bool id) { return Foo::logFromNamespace(id); }
+	std::string logFromClassWithNoLogTypeMember(bool id) { ClassWithNoLogType c; return c.logFromMember(id); }
+	std::string logFromClassWithNoLogTypeStatic(bool id) { return ClassWithNoLogType::logFromStatic(id); }
+	std::string logFromClassWithLogTypeMember(bool id) { ClassWithLogType c; return c.logFromMember(id); }
+	std::string logFromClassWithLogTypeStatic(bool id) { return ClassWithLogType::logFromStatic(id); }
+	
+	void ensure_has(const std::string& message,
+		const std::string& actual, const std::string& expected)
+	{
+		std::string::size_type n1 = actual.find(expected);
+		if (n1 == std::string::npos)
+		{
+			std::stringstream ss;
+			ss << message << ": " << "expected to find a copy of " << expected
+				<< " in actual " << actual;
+			throw tut::failure(ss.str().c_str());
+		}
+	}
+	
+	typedef std::string (*LogFromFunction)(bool);
+	void testLogName(TestRecorder& recorder, LogFromFunction f,
+		const std::string& class_name = "")
+	{
+		recorder.clearMessages();
+		std::string name = f(false);
+		f(true);
+		
+		std::string messageWithoutName = recorder.message(0);
+		std::string messageWithName = recorder.message(1);
+		
+		ensure_has(name + " logged without name",
+			messageWithoutName, name);
+		ensure_has(name + " logged with name",
+			messageWithName, name);
+
+		if (!class_name.empty())
+		{
+			ensure_has(name + "logged without name",
+				messageWithoutName, class_name);
+			ensure_has(name + "logged with name",
+				messageWithName, class_name);
+		}
+	}
+}
+
+namespace tut
+{
+	template<> template<>
+		// 	class/function information in output
+	void ErrorTestObject::test<6>()
+	{
+		testLogName(mRecorder, logFromGlobal);
+		testLogName(mRecorder, logFromStatic);
+		testLogName(mRecorder, logFromAnon);
+		testLogName(mRecorder, logFromNamespace);
+		//testLogName(mRecorder, logFromClassWithNoLogTypeMember, "ClassWithNoLogType");
+		//testLogName(mRecorder, logFromClassWithNoLogTypeStatic, "ClassWithNoLogType");
+			// XXX: figure out what the exepcted response is for these
+		testLogName(mRecorder, logFromClassWithLogTypeMember, "ClassWithLogType");
+		testLogName(mRecorder, logFromClassWithLogTypeStatic, "ClassWithLogType");
+	}
+}
+
+namespace
+{
+	std::string innerLogger()
+	{
+		llinfos << "inside" << llendl;
+		return "moo";
+	}
+	
+	std::string outerLogger()
+	{
+		llinfos << "outside(" << innerLogger() << ")" << llendl;
+		return "bar";
+	}
+	
+	void uberLogger()
+	{
+		llinfos << "uber(" << outerLogger() << "," << innerLogger() << ")" << llendl;
+	}
+	
+	class LogWhileLogging
+	{
+	public:
+		void print(std::ostream& out) const
+		{
+			llinfos << "logging" << llendl;
+			out << "baz";
+		}
+	};
+
+	std::ostream& operator<<(std::ostream& out, const LogWhileLogging& l)
+		{ l.print(out); return out; }
+
+	void metaLogger()
+	{
+		LogWhileLogging l;
+		llinfos << "meta(" << l << ")" << llendl;
+	}
+	
+}
+
+namespace tut
+{			
+	template<> template<>
+		// handle nested logging
+	void ErrorTestObject::test<7>()
+	{
+		outerLogger();
+		ensure_message_contains(0, "inside");
+		ensure_message_contains(1, "outside(moo)");
+		ensure_message_count(2);
+		
+		uberLogger();
+		ensure_message_contains(2, "inside");
+		ensure_message_contains(3, "inside");
+		ensure_message_contains(4, "outside(moo)");
+		ensure_message_contains(5, "uber(bar,moo)");
+		ensure_message_count(6);
+		
+		metaLogger();
+		ensure_message_contains(6, "logging");
+		ensure_message_contains(7, "meta(baz)");
+		ensure_message_count(8);
+	}
+	
+	template<> template<>
+		// special handling of llerrs calls
+	void ErrorTestObject::test<8>()
+	{
+		LLError::setPrintLocation(false);
+		std::string location = errorReturningLocation();
+		
+		ensure_message_contains(0, location + "error");
+		ensure_message_contains(1, "die");
+		ensure_message_count(2);
+		
+		ensure("fatal callback called", fatalWasCalled);
+	}
+}
+
+namespace
+{
+	std::string roswell()
+	{
+		return "1947-07-08T03:04:05Z";
+	}
+	
+	void ufoSighting()
+	{
+		llinfos << "ufo" << llendl;
+	}
+}
+
+namespace tut
+{	
+	template<> template<>
+		// time in output (for recorders that need it)
+	void ErrorTestObject::test<9>()
+	{
+		LLError::setTimeFunction(roswell);
+
+		mRecorder.setWantsTime(false);
+		ufoSighting();
+		ensure_message_contains(0, "ufo");
+		ensure_message_does_not_contain(0, roswell());
+		
+		mRecorder.setWantsTime(true);
+		ufoSighting();
+		ensure_message_contains(1, "ufo");
+		ensure_message_contains(1, roswell());
+	}
+	
+	template<> template<>
+		// output order
+	void ErrorTestObject::test<10>()
+	{
+		LLError::setPrintLocation(true);
+		LLError::setTimeFunction(roswell);
+		mRecorder.setWantsTime(true);
+		std::string locationAndFunction = writeReturningLocationAndFunction();
+		
+		ensure_equals("order is time type location function message",
+			mRecorder.message(0),
+			roswell() + " INFO: " + locationAndFunction + ": apple");
+	}
+
+	template<> template<>
+		// multiple recorders
+	void ErrorTestObject::test<11>()
+	{
+		TestRecorder altRecorder;
+		LLError::addRecorder(&altRecorder);
+		
+		llinfos << "boo" << llendl;
+
+		ensure_message_contains(0, "boo");
+		ensure_equals("alt recorder count", altRecorder.countMessages(), 1);
+		ensure_contains("alt recorder message 0", altRecorder.message(0), "boo");
+		
+		LLError::setTimeFunction(roswell);
+
+		TestRecorder anotherRecorder;
+		anotherRecorder.setWantsTime(true);
+		LLError::addRecorder(&anotherRecorder);
+		
+		llinfos << "baz" << llendl;
+
+		std::string when = roswell();
+		
+		ensure_message_does_not_contain(1, when);
+		ensure_equals("alt recorder count", altRecorder.countMessages(), 2);
+		ensure_does_not_contain("alt recorder message 1", altRecorder.message(1), when);
+		ensure_equals("another recorder count", anotherRecorder.countMessages(), 1);
+		ensure_contains("another recorder message 0", anotherRecorder.message(0), when);
+	}
+}
+
+class TestAlpha
+{
+	LOG_CLASS(TestAlpha);
+public:
+	static void doDebug()	{ lldebugs << "add dice" << llendl; }
+	static void doInfo()	{ llinfos  << "any idea" << llendl; }
+	static void doWarn()	{ llwarns  << "aim west" << llendl; }
+	static void doError()	{ llerrs   << "ate eels" << llendl; }
+	static void doAll() { doDebug(); doInfo(); doWarn(); doError(); }
+};
+
+class TestBeta
+{
+	LOG_CLASS(TestBeta);
+public:
+	static void doDebug()	{ lldebugs << "bed down" << llendl; }
+	static void doInfo()	{ llinfos  << "buy iron" << llendl; }
+	static void doWarn()	{ llwarns  << "bad word" << llendl; }
+	static void doError()	{ llerrs   << "big easy" << llendl; }
+	static void doAll() { doDebug(); doInfo(); doWarn(); doError(); }
+};
+
+namespace tut
+{
+	template<> template<>
+		// filtering by class
+	void ErrorTestObject::test<12>()
+	{
+		LLError::setDefaultLevel(LLError::LEVEL_WARN);
+		LLError::setClassLevel("TestBeta", LLError::LEVEL_INFO);
+		
+		TestAlpha::doAll();
+		TestBeta::doAll();
+		
+		ensure_message_contains(0, "aim west");
+		ensure_message_contains(1, "error");
+		ensure_message_contains(2, "ate eels");
+		ensure_message_contains(3, "buy iron");
+		ensure_message_contains(4, "bad word");
+		ensure_message_contains(5, "error");
+		ensure_message_contains(6, "big easy");
+		ensure_message_count(7);
+	}
+	
+	template<> template<>
+		// filtering by function, and that it will override class filtering
+	void ErrorTestObject::test<13>()
+	{
+		LLError::setDefaultLevel(LLError::LEVEL_DEBUG);
+		LLError::setClassLevel("TestBeta", LLError::LEVEL_WARN);
+		LLError::setFunctionLevel("TestBeta::doInfo", LLError::LEVEL_DEBUG);
+		LLError::setFunctionLevel("TestBeta::doError", LLError::LEVEL_NONE);
+		
+		TestBeta::doAll();
+		ensure_message_contains(0, "buy iron");
+		ensure_message_contains(1, "bad word");
+		ensure_message_count(2);
+	}
+	
+	template<> template<>
+		// filtering by file
+		// and that it is overridden by both class and function filtering
+	void ErrorTestObject::test<14>()
+	{
+		LLError::setDefaultLevel(LLError::LEVEL_DEBUG);
+		LLError::setFileLevel(LLError::abbreviateFile(__FILE__),
+									LLError::LEVEL_WARN);
+		LLError::setClassLevel("TestAlpha", LLError::LEVEL_INFO);
+		LLError::setFunctionLevel("TestAlpha::doError",
+									LLError::LEVEL_NONE);
+		LLError::setFunctionLevel("TestBeta::doError",
+									LLError::LEVEL_NONE);
+		
+		TestAlpha::doAll();
+		TestBeta::doAll();
+		ensure_message_contains(0, "any idea");
+		ensure_message_contains(1, "aim west");
+		ensure_message_contains(2, "bad word");
+		ensure_message_count(3);
+	}
+	
+	template<> template<>
+		// proper cached, efficient lookup of filtering
+	void ErrorTestObject::test<15>()
+	{
+		LLError::setDefaultLevel(LLError::LEVEL_NONE);
+
+		TestAlpha::doInfo();
+		ensure_message_count(0);
+		ensure_equals("first check", LLError::shouldLogCallCount(), 1);
+		TestAlpha::doInfo();
+		ensure_message_count(0);
+		ensure_equals("second check", LLError::shouldLogCallCount(), 1);
+
+		LLError::setClassLevel("TestAlpha", LLError::LEVEL_DEBUG);
+		TestAlpha::doInfo();
+		ensure_message_count(1);
+		ensure_equals("third check", LLError::shouldLogCallCount(), 2);
+		TestAlpha::doInfo();
+		ensure_message_count(2);
+		ensure_equals("fourth check", LLError::shouldLogCallCount(), 2);
+
+		LLError::setClassLevel("TestAlpha", LLError::LEVEL_WARN);
+		TestAlpha::doInfo();
+		ensure_message_count(2);
+		ensure_equals("fifth check", LLError::shouldLogCallCount(), 3);
+		TestAlpha::doInfo();
+		ensure_message_count(2);
+		ensure_equals("sixth check", LLError::shouldLogCallCount(), 3);
+	}
+	
+	template<> template<>
+		// configuration from LLSD
+	void ErrorTestObject::test<16>()
+	{
+		std::string this_file = LLError::abbreviateFile(__FILE__);
+		LLSD config;
+		config["print-location"] = true;
+		config["default-level"] = "DEBUG";
+		
+		LLSD set1;
+		set1["level"] = "WARN";
+		set1["files"][0] = this_file;
+		
+		LLSD set2;
+		set2["level"] = "INFO";
+		set2["classes"][0] = "TestAlpha";
+		
+		LLSD set3;
+		set3["level"] = "NONE";
+		set3["functions"][0] = "TestAlpha::doError";
+		set3["functions"][1] = "TestBeta::doError";
+		
+		config["settings"][0] = set1;
+		config["settings"][1] = set2;
+		config["settings"][2] = set3;
+		
+		LLError::configure(config);
+		
+		TestAlpha::doAll();
+		TestBeta::doAll();
+		ensure_message_contains(0, "any idea");
+		ensure_message_contains(0, this_file);
+		ensure_message_contains(1, "aim west");
+		ensure_message_contains(2, "bad word");
+		ensure_message_count(3);
+		
+		// make sure reconfiguring works
+		LLSD config2;
+		config2["default-level"] = "WARN";
+		
+		LLError::configure(config2);
+		
+		TestAlpha::doAll();
+		TestBeta::doAll();
+		ensure_message_contains(3, "aim west");
+		ensure_message_does_not_contain(3, this_file);
+		ensure_message_contains(4, "error");
+		ensure_message_contains(5, "ate eels");
+		ensure_message_contains(6, "bad word");
+		ensure_message_contains(7, "error");
+		ensure_message_contains(8, "big easy");
+		ensure_message_count(9);
+	}
+}	
+
+/* Tests left:
+	handling of classes without LOG_CLASS
+
+	live update of filtering from file	
+	
+	syslog recorder
+	file recorder
+	cerr/stderr recorder
+	fixed buffer recorder
+	windows recorder
+
+	mutex use when logging (?)
+	strange careful about to crash handling (?)
+*/