From 9a43d50969ecc34d9a3bc8944bc2182e55f7a712 Mon Sep 17 00:00:00 2001
From: mrbesen <y.g.2@gmx.de>
Date: Wed, 26 Oct 2022 21:16:56 +0200
Subject: [PATCH] qt support

---
 Log.cpp  | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 Log.h    | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 Makefile |  3 ++-
 3 files changed, 100 insertions(+), 1 deletion(-)

diff --git a/Log.cpp b/Log.cpp
index 95c1f6c..32cd703 100644
--- a/Log.cpp
+++ b/Log.cpp
@@ -10,8 +10,29 @@
 #include <mutex>
 #endif
 
+#if LOG_ENABLEQT == 1
+#include <QString>
+#endif
+
 namespace Log {
 
+#if LOG_ENABLEQT == 1
+void qtMessageHandler(QtMsgType type, const QMessageLogContext& context, const QString& message) {
+
+	// convert type to Log::Level
+	Log::Level lvl = Log::Level::off;
+	switch(type) {
+		case QtDebugMsg:    lvl = Log::Level::debug; break;
+		case QtInfoMsg:     lvl = Log::Level::info;  break;
+		case QtWarningMsg:  lvl = Log::Level::warn;  break;
+		case QtCriticalMsg: lvl = Log::Level::error; break;
+		case QtFatalMsg:    lvl = Log::Level::fatal; break;
+	}
+
+	Entry(lvl, context) << message.toStdString();
+}
+#endif
+
 /*
  * abstract class Output
  *   default implementations
@@ -147,6 +168,13 @@ void log(Level lvl, std::stringbuf* strb) {
 /*
  * class Entry
  */
+#if LOG_ENABLEQT == 1
+Entry::Entry(Level lvl, const QMessageLogContext& context) : lvl{lvl}, context{&context} {
+	for(const auto& metafunc : entryMetaFunctions) {
+		metafunc(ss, *this);
+	}
+}
+#endif
 
 Entry::Entry(Level lvl) : lvl{lvl} {
 	for(const auto& metafunc : entryMetaFunctions) {
@@ -182,6 +210,16 @@ std::ostream& defaultEntryMetaLevel(std::ostream& os, const Entry& e) {
 	return os << LevelTag[static_cast<int>(e.getLevel())];
 }
 
+#if LOG_ENABLEQT == 1
+std::ostream& defaultEntryMetaQtContext(std::ostream& os, const Entry& e) {
+	if (e.getContext() && e.getContext()->file) {
+		const std::string file = e.getContext()->file;
+		return os << file << ':' << e.getContext()->line;
+	}
+	return os << "-:-";
+}
+#endif
+
 void init() {
 	// add default console logger
 	if (outputs.empty()) {
@@ -196,11 +234,24 @@ void init() {
 	entryMetaFunctions = {
 		defaultEntryMetaTime,
 		defaultEntryMetaLevel,
+
+		#if LOG_ENABLEQT == 1
+		space,
+		defaultEntryMetaQtContext,
+		#endif
+
 		space
 	};
+
+	#if LOG_ENABLEQT == 1
+	qInstallMessageHandler( &Log::qtMessageHandler );
+	#endif
 }
 
 void stop() {
+	#if LOG_ENABLEQT == 1
+	qInstallMessageHandler( nullptr );
+	#endif
 	outputs.clear();
 }
 
diff --git a/Log.h b/Log.h
index b172eb5..3072eea 100644
--- a/Log.h
+++ b/Log.h
@@ -9,9 +9,45 @@
 #define LOG_USEMUTEX 0
 #endif
 
+#ifndef LOG_ENABLEQT
+#define LOG_ENABLEQT 0
+#endif
+
+#if LOG_ENABLEQT == 1
+#include <QMessageLogContext>
+#include <QDebug>
+#endif
+
+#if LOG_ENABLEQT == 1
+template<typename T>
+QDebug operator<<(QDebug dbg, const T& str) {
+	std::ostringstream stream;
+	stream << str;
+	QString conv = QString::fromStdString(stream.str());
+	QDebugStateSaver saver(dbg);
+	dbg << conv;
+	return dbg;
+}
+
+/*
+// string specialisation, not allowed, because multiple definitions of the same operator are not allowed
+template<>
+QDebug operator<<(QDebug dbg, const std::string& str) {
+	QDebugStateSaver saver(dbg);
+	QString conv = QString::fromStdString(str);
+	dbg << conv;
+	return dbg;
+}
+*/
+#endif
+
 namespace Log {
 enum class Level { off = 0, fatal, error, warn, note, info, debug, trace };
 
+#if LOG_ENABLEQT == 1
+void qtMessageHandler(QtMsgType type, const QMessageLogContext& context, const QString& message);
+#endif
+
 // set up the logger with a ConsoleOutput
 void init();
 // close all output streams
@@ -30,6 +66,11 @@ class Entry {
 private:
 	std::stringstream ss;
 	const Level lvl;
+#if LOG_ENABLEQT == 1
+	const QMessageLogContext* context = nullptr;
+	Entry(Level lvl, const QMessageLogContext&);
+	friend void qtMessageHandler(QtMsgType type, const QMessageLogContext& context, const QString& message);
+#endif
 
 	void addMetadataHeader();
 
@@ -45,6 +86,12 @@ public:
 		return lvl;
 	}
 
+#if LOG_ENABLEQT == 1
+	constexpr const QMessageLogContext* getContext() const {
+		return context;
+	}
+#endif
+
 	using MetaFunction = std::function<std::ostream&(std::ostream&, const Entry&)>;
 
 	template <typename T> Entry& operator<<(T&& msg) {
diff --git a/Makefile b/Makefile
index 89fcc76..0b94e75 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,8 @@
 TARGET = Log.o
 TEST   = test
 LOG_USEMUTEX ?= 0
-CXXFLAGS = -O2 -g -std=c++11 -Wall -Wextra -pedantic-errors -MMD -DLOG_USEMUTEX=$(LOG_USEMUTEX)
+LOG_ENABLEQT ?= 0
+CXXFLAGS = -O2 -g -std=c++11 -Wall -Wextra -pedantic-errors -MMD -DLOG_USEMUTEX=$(LOG_USEMUTEX) -DLOG_ENABLEQT=$(LOG_ENABLEQT)
 
 .PHONY: all clean