WIP

src/CMakeLists.txt

@@ -1,3 +1,6 @@
 cmake_minimum_required(VERSION 3.20)
 
 add_subdirectory(example_boost)
+add_subdirectory(hello_world)
+add_subdirectory(hello_world_awesome)
+add_subdirectory(awesome_log)

src/awesome_log/CMakeLists.txt

@@ -0,0 +1,21 @@
+cmake_minimum_required(VERSION 3.20)
+
+project(awesome_log)
+
+add_library(
+    ${PROJECT_NAME}
+    ./src/console_writer.cpp
+    ./src/log.cpp
+    ./src/null_writer.cpp
+    ./src/scoped_log.cpp
+)
+
+set_property(
+    TARGET ${PROJECT_NAME}
+    PROPERTY CXX_STANDARD 20
+)
+
+target_include_directories(
+    ${PROJECT_NAME}
+    PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include
+)

src/awesome_log/include/awesome_log/console_writer.hpp

@@ -0,0 +1,14 @@
+
+#pragma once
+
+#include "writer_interface.hpp"
+
+namespace awesome_log
+{
+    class console_writer : public writer_interface
+    {
+    public:
+        ~console_writer() override;
+        void log(std::string_view msg) override;
+    };
+}

src/awesome_log/include/awesome_log/log.hpp

@@ -0,0 +1,12 @@
+
+#pragma once
+
+#include <memory>
+
+namespace awesome_log
+{
+    class writer_interface;
+
+    writer_interface& get_writer();
+    void set_writer(const std::shared_ptr<writer_interface>& writer);
+}

src/awesome_log/include/awesome_log/null_writer.hpp

@@ -0,0 +1,14 @@
+
+#pragma once
+
+#include "writer_interface.hpp"
+
+namespace awesome_log
+{
+    class null_writer : public writer_interface
+    {
+    public:
+        ~null_writer() override;
+        void log(std::string_view msg) override;
+    };
+}

src/awesome_log/include/awesome_log/scoped_log.hpp

@@ -0,0 +1,27 @@
+
+#pragma once
+
+#include <string>
+#include <string_view>
+
+namespace awesome_log
+{
+    class scoped_log
+    {
+    public:
+        scoped_log(std::string_view msg);
+        ~scoped_log();
+
+        scoped_log() = delete;
+
+        // No copying or moving allowed.
+        scoped_log(const scoped_log&) = delete;
+        scoped_log(scoped_log&&) = delete;
+        scoped_log& operator=(const scoped_log&) = delete;
+        scoped_log& operator=(scoped_log&&) = delete;
+
+        private:
+        std::string m_msg;
+        int m_uncaught_exceptions;
+    };
+}

src/awesome_log/include/awesome_log/writer_interface.hpp

@@ -0,0 +1,15 @@
+
+#pragma once
+
+#include <string_view>
+
+namespace awesome_log
+{
+    class writer_interface
+    {
+    public:
+        virtual ~writer_interface() = default;
+
+        virtual void log(std::string_view msg) = 0;
+    };
+}

src/awesome_log/src/console_writer.cpp

@@ -0,0 +1,12 @@
+
+#include <awesome_log/console_writer.hpp>
+#include <iostream>
+
+using namespace awesome_log;
+
+console_writer::~console_writer() = default;
+
+void console_writer::log(std::string_view msg)
+{
+    std::cout << msg << std::endl;
+}

src/awesome_log/src/log.cpp

@@ -0,0 +1,23 @@
+#include <awesome_log/log.hpp>
+#include <awesome_log/null_writer.hpp>
+
+using awesome_log::writer_interface;
+
+namespace
+{
+    std::shared_ptr<writer_interface> g_instance;
+}
+
+writer_interface& awesome_log::get_writer()
+{
+    if(!g_instance)
+    {
+        g_instance = std::make_shared<null_writer>();
+    }
+    return *g_instance;
+}
+
+void awesome_log::set_writer(const std::shared_ptr<writer_interface>& writer)
+{
+    g_instance = writer;
+}

src/awesome_log/src/null_writer.cpp

@@ -0,0 +1,10 @@
+
+#include <awesome_log/null_writer.hpp>
+
+using namespace awesome_log;
+
+null_writer::~null_writer() = default;
+
+void null_writer::log(std::string_view)
+{
+}

src/awesome_log/src/scoped_log.cpp

@@ -0,0 +1,32 @@
+#include <awesome_log/scoped_log.hpp>
+#include <awesome_log/log.hpp>
+#include <awesome_log/writer_interface.hpp>
+#include <sstream>
+#include <exception>
+
+using namespace awesome_log;
+
+scoped_log::scoped_log(std::string_view msg)
+    : m_msg(msg)
+    , m_uncaught_exceptions(std::uncaught_exceptions())
+{
+    std::stringstream ss;
+    ss << "> " << m_msg;
+
+    get_writer().log(ss.str());
+}
+
+scoped_log::~scoped_log()
+{
+    bool is_stack_unwinding = (m_uncaught_exceptions != std::uncaught_exceptions());
+
+    std::stringstream ss;
+    ss << "< " << m_msg;
+    
+    if (is_stack_unwinding)
+    {
+        ss << " (stack unwinding)";
+    }
+
+    get_writer().log(ss.str());
+}

src/example_boost/CMakeLists.txt

@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.20)
 
 find_package(Boost 1.88.0 REQUIRED COMPONENTS serialization)
 
-project(hello_world_boost)
+project(example_boost)
 
 add_executable(
     ${PROJECT_NAME}

src/example_boost/src/main.cpp

@@ -5,8 +5,8 @@
 
 struct position
 {
-    double x;
+    int x;
-    double y;
+    int y;
 
     template<class Archive>
     void serialize(Archive & ar, const unsigned int /*version*/)
@@ -25,7 +25,7 @@ struct position
 
 int main(int argc, char* argv[])
 {
-    position myposition{.x=123.0, .y=456.0};
+    position myposition{.x=123, .y=456};
 
     std::stringstream ss;
     {

src/hello_world/CMakeLists.txt

@@ -0,0 +1,13 @@
+cmake_minimum_required(VERSION 3.20)
+
+project(hello_world)
+
+add_executable(
+    ${PROJECT_NAME}
+    src/main.cpp
+)
+
+set_property(
+    TARGET ${PROJECT_NAME}
+    PROPERTY CXX_STANDARD 20
+)

src/hello_world/src/main.cpp

@@ -0,0 +1,7 @@
+
+#include <iostream>
+
+int main(int argc, char* argv[])
+{
+    std::cout << "Hello world" << std::endl;
+}

src/hello_world_awesome/CMakeLists.txt

@@ -0,0 +1,18 @@
+cmake_minimum_required(VERSION 3.20)
+
+project(hello_world_awesome)
+
+add_executable(
+    ${PROJECT_NAME}
+    src/main.cpp
+)
+
+target_link_libraries(
+    ${PROJECT_NAME}
+    awesome_log
+)
+
+set_property(
+    TARGET ${PROJECT_NAME}
+    PROPERTY CXX_STANDARD 20
+)

src/hello_world_awesome/src/main.cpp

@@ -0,0 +1,29 @@
+#include <awesome_log/log.hpp>
+#include <awesome_log/scoped_log.hpp>
+#include <awesome_log/console_writer.hpp>
+
+#include <iostream>
+#include <memory>
+
+using awesome_log::scoped_log;
+
+int main(int argc, char* argv[])
+{
+    awesome_log::set_writer(std::make_shared<awesome_log::console_writer>());
+
+    {
+        scoped_log scoped("main.cpp, printing text");
+        std::cout << "Hello world" << std::endl;
+    }
+
+    try
+    {
+        scoped_log scoped("main.cpp, playing with exceptions");
+        throw std::runtime_error("Let's play!");
+        // ... unreachable code goes here.
+    }
+    catch(const std::exception& e)
+    {
+        std::cout << "Caught an exception, as expected in this example" << std::endl;
+    }
+}