From b04bfab964bbbbb32e915f0988d34c0dd70ab75b Mon Sep 17 00:00:00 2001
From: "Timur A. Fatkhullin" <timur@sao.ru>
Date: Mon, 6 Jul 2026 18:59:09 +0300
Subject: [PATCH] add loggers

---
 CMakeLists.txt                              |  40 ++++
 include/snipplib/concepts/snplib_concepts.h |  14 ++
 include/snipplib/concepts/snplib_traits.h   |   1 +
 include/snipplib/utils/snplib_logger.h      | 222 ++++++++++++++++++++
 include/snipplib/utils/snplib_utils.h       |   4 +-
 5 files changed, 280 insertions(+), 1 deletion(-)
 create mode 100644 include/snipplib/utils/snplib_logger.h

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0b821a8..543e19a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,12 +3,42 @@ project(snipplib VERSION 0.1.0 LANGUAGES CXX)
 
 option(SNPLIB_BUILD_EXAMPLES "Build examples" ON)
 
+option(SNPLIB_USE_SPDLOG "Use of spdlog library" ON)
+
+if(SNPLIB_USE_SPDLOG)
+    find_package(spdlog CONFIG)
+    if(NOT spdlog_FOUND)
+        FetchContent_Declare(
+            spdlog
+            GIT_REPOSITORY "https://github.com/gabime/spdlog.git"
+            GIT_TAG "v1.17.0"
+            GIT_SHALLOW TRUE
+            GIT_SUBMODULES ""
+            GIT_PROGRESS TRUE
+            # CMAKE_ARGS
+            # -DSPDLOG_USE_STD_FORMAT=ON
+            # -DSPDLOG_FMT_EXTERNAL=OFF
+            OVERRIDE_FIND_PACKAGE
+        )
+
+        set(SPDLOG_USE_STD_FORMAT ON CACHE INTERNAL "Use of C++20 std::format")
+        set(SPDLOG_FMT_EXTERNAL
+            OFF
+            CACHE INTERNAL
+            "Turn off external fmt library"
+        )
+        set(SPDLOG_INSTALL ON CACHE BOOL "Enable spdlog installation" FORCE)
+        FetchContent_MakeAvailable(spdlog)
+    endif()
+endif(SNPLIB_USE_SPDLOG)
+
 set(LIB_HEADERS
     include/snipplib/concepts/snplib_concepts.h
     include/snipplib/concepts/snplib_traits.h
     include/snipplib/utils/snplib_hash.h
     include/snipplib/utils/snplib_string.h
     include/snipplib/utils/snplib_keyvalue_expr.h
+    include/snipplib/utils/snplib_logger.h
     include/snipplib/utils/snplib_utils.h
     include/snipplib/containers/snplib_hmap.h
     include/snipplib/containers/snplib_hvec.h
@@ -24,6 +54,16 @@ target_include_directories(
         "$<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/include>"
         "$<INSTALL_INTERFACE:include/${PROJECT_NAME}>"
 )
+if(SNPLIB_USE_SPDLOG)
+    target_compile_definitions(
+        ${PROJECT_NAME}
+        INTERFACE
+            SPDLOG_USE_STD_FORMAT=1
+            SPDLOG_FMT_EXTERNAL=0
+            SNPLIB_SPDLOGGER=1
+    )
+    target_link_libraries(${PROJECT_NAME} INTERFACE spdlog::spdlog_header_only)
+endif()
 
 if(SNPLIB_BUILD_EXAMPLES)
     set(EXAM_STRING str_exam)
diff --git a/include/snipplib/concepts/snplib_concepts.h b/include/snipplib/concepts/snplib_concepts.h
index fde448d..42a7c29 100644
--- a/include/snipplib/concepts/snplib_concepts.h
+++ b/include/snipplib/concepts/snplib_concepts.h
@@ -200,4 +200,18 @@ template <typename T, typename UT = void>
 concept snplib_async_retval_c = snplib_awaitable_c<T, UT> && snplib_expected_c<UT>;
 
 
+
+/*                          a concept for generic logger class                         */
+
+template <typename T>
+concept snplib_logger_c = requires(T t) {
+    { t.logInfo(std::declval<std::string const&>()) };
+    { t.logWarn(std::declval<std::string const&>()) };
+    { t.logDebug(std::declval<std::string const&>()) };
+    { t.logError(std::declval<std::string const&>()) };
+    { t.logTrace(std::declval<std::string const&>()) };
+};
+
+
+
 }  // namespace snplib
\ No newline at end of file
diff --git a/include/snipplib/concepts/snplib_traits.h b/include/snipplib/concepts/snplib_traits.h
index 2e38103..1791b89 100644
--- a/include/snipplib/concepts/snplib_traits.h
+++ b/include/snipplib/concepts/snplib_traits.h
@@ -81,4 +81,5 @@ struct snplib_func_traits_t<F&&> : snplib_func_traits_t<F> {
 template <typename T>
 using snplib_func_arg1_t = typename snplib_func_traits_t<T>::arg1_t;
 
+
 }  // namespace snplib
\ No newline at end of file
diff --git a/include/snipplib/utils/snplib_logger.h b/include/snipplib/utils/snplib_logger.h
new file mode 100644
index 0000000..9bd174f
--- /dev/null
+++ b/include/snipplib/utils/snplib_logger.h
@@ -0,0 +1,222 @@
+#pragma once
+
+#include <list>
+#ifdef SNPLIB_SPDLOGGER
+#include <spdlog/logger.h>
+#endif
+
+#include "../concepts/snplib_concepts.h"
+
+namespace snplib
+{
+
+/*                          snplib_logger_c-like class adaptor to use formating                         */
+
+// template <snplib_logger_c LoggerT>
+// struct snplib_logger_fmt_adaptor_t : public LoggerT {
+//     template<typename ...CtorArgTs>
+//     snplib_logger_fmt_adaptor_t(CtorArgTs&&... ctor_args): LoggerT(std::forward<CtorArgTs>(ctor_args)...) {}
+
+//     ~snplib_logger_fmt_adaptor_t() = default;
+
+//     template <std::formattable<char>... ArgTs>
+//     auto logInfo(std::format_string<ArgTs...> fmt, ArgTs&&... args)
+//     {
+//         return logInfo(std::format(fmt, std::forward<ArgTs>(args)...));
+//     }
+
+//     template <std::formattable<char>... ArgTs>
+//     auto logWarn(std::format_string<ArgTs...> fmt, ArgTs&&... args)
+//     {
+//         return logWarn(std::format(fmt, std::forward<ArgTs>(args)...));
+//     }
+
+//     template <std::formattable<char>... ArgTs>
+//     auto logDebug(std::format_string<ArgTs...> fmt, ArgTs&&... args)
+//     {
+//         return logDebug(std::format(fmt, std::forward<ArgTs>(args)...));
+//     }
+
+//     template <std::formattable<char>... ArgTs>
+//     auto logError(std::format_string<ArgTs...> fmt, ArgTs&&... args)
+//     {
+//         return logError(std::format(fmt, std::forward<ArgTs>(args)...));
+//     }
+
+//     template <std::formattable<char>... ArgTs>
+//     auto logTrace(std::format_string<ArgTs...> fmt, ArgTs&&... args)
+//     {
+//         return logTrace(std::format(fmt, std::forward<ArgTs>(args)...));
+//     }
+// };
+
+
+
+/*                          a NULL-logger                           */
+
+struct snplib_null_logger_t {
+    void logInfo(std::string const&) {}
+    void logWarn(std::string const&) {}
+    void logDebug(std::string const&) {}
+    void logError(std::string const&) {}
+    void logTrace(std::string const&) {}
+};
+
+
+#ifdef SNPLIB_SPDLOGGER
+
+/*                              SPDLOG-library based advanced single/multithreaded logger                           */
+
+class snplib_spdlog_logger_t
+{
+protected:
+    std::shared_ptr<spdlog::logger> _loggerSPtr;
+    std::list<std::string> _currentLogPatternRange{};
+    std::string _currentLogPattern{};
+
+public:
+    // [year-month-day time.millisecs][log-level]: log-message
+    constexpr static std::array LOGGER_DEFAULT_FORMAT = {std::string_view{"[%Y-%m-%d %T.%e]"}, std::string_view{"[%l]"},
+                                                         std::string_view{": "}, std::string_view{"%v"}};
+
+
+
+    template <std::ranges::input_range R = decltype(LOGGER_DEFAULT_FORMAT)>
+        requires snplib_input_char_range_c<std::ranges::range_value_t<R>>
+    snplib_spdlog_logger_t(std::shared_ptr<spdlog::logger> logger, R&& pattern_range = LOGGER_DEFAULT_FORMAT)
+        : _loggerSPtr(logger)
+    {
+        if (std::distance(pattern_range.begin(), pattern_range.end())) {
+            std::ranges::copy(
+                pattern_range | std::views::transform([](const auto& el) { return std::string(el.begin(), el.end()); }),
+                std::back_inserter(_currentLogPatternRange));
+        } else {
+            std::ranges::copy(LOGGER_DEFAULT_FORMAT | std::views::transform([](const auto& el) {
+                                  return std::string(el.begin(), el.end());
+                              }),
+                              std::back_inserter(_currentLogPatternRange));
+        }
+
+        std::ranges::copy(std::views::join(_currentLogPatternRange), std::back_inserter(_currentLogPattern));
+
+        _loggerSPtr->set_pattern(_currentLogPattern);
+    }
+
+    virtual ~snplib_spdlog_logger_t() = default;
+
+    void logMessage(spdlog::level::level_enum level, const std::string& msg)
+    {
+        _loggerSPtr->log(level, msg);
+    }
+
+    // specialized for given level methods
+
+    void logCritical(const std::string& msg)
+    {
+        logMessage(spdlog::level::critical, msg);
+    }
+
+    void logError(const std::string& msg)
+    {
+        logMessage(spdlog::level::err, msg);
+    }
+
+    void logWarn(const std::string& msg)
+    {
+        logMessage(spdlog::level::warn, msg);
+    }
+
+    void logInfo(const std::string& msg)
+    {
+        logMessage(spdlog::level::info, msg);
+    }
+
+    void logDebug(const std::string& msg)
+    {
+        logMessage(spdlog::level::debug, msg);
+    }
+
+    void logTrace(const std::string& msg)
+    {
+        logMessage(spdlog::level::trace, msg);
+    }
+
+    template <std::formattable<char>... ArgTs>
+    void logMessage(spdlog::level::level_enum level, spdlog::format_string_t<ArgTs...> fmt, ArgTs&&... args)
+    {
+        _loggerSPtr->log(level, fmt, std::forward<ArgTs>(args)...);
+    }
+
+    template <std::formattable<char>... ArgTs>
+    void logCritical(spdlog::format_string_t<ArgTs...> fmt, ArgTs&&... args)
+    {
+        _loggerSPtr->log(spdlog::level::critical, fmt, std::forward<ArgTs>(args)...);
+    }
+
+    template <std::formattable<char>... ArgTs>
+    void logError(spdlog::format_string_t<ArgTs...> fmt, ArgTs&&... args)
+    {
+        _loggerSPtr->log(spdlog::level::err, fmt, std::forward<ArgTs>(args)...);
+    }
+
+    template <std::formattable<char>... ArgTs>
+    void logWarn(spdlog::format_string_t<ArgTs...> fmt, ArgTs&&... args)
+    {
+        _loggerSPtr->log(spdlog::level::warn, fmt, std::forward<ArgTs>(args)...);
+    }
+
+    template <std::formattable<char>... ArgTs>
+    void logInfo(spdlog::format_string_t<ArgTs...> fmt, ArgTs&&... args)
+    {
+        _loggerSPtr->log(spdlog::level::info, fmt, std::forward<ArgTs>(args)...);
+    }
+
+    template <std::formattable<char>... ArgTs>
+    void logDebug(spdlog::format_string_t<ArgTs...> fmt, ArgTs&&... args)
+    {
+        _loggerSPtr->log(spdlog::level::debug, fmt, std::forward<ArgTs>(args)...);
+    }
+
+    template <std::formattable<char>... ArgTs>
+    void logTrace(spdlog::format_string_t<ArgTs...> fmt, ArgTs&&... args)
+    {
+        _loggerSPtr->log(spdlog::level::trace, fmt, std::forward<ArgTs>(args)...);
+    }
+
+
+    // 'after_idx' is 0-based index!
+    void addMarkToPatternIdx(snplib_input_char_range_c auto&& mark, size_t after_idx = 1)
+        requires(!std::is_pointer_v<std::decay_t<decltype(mark)>>)
+    {
+        if constexpr (std::is_pointer_v<std::decay_t<decltype(mark)>>) {
+            addMarkToPatternIdx(std::string_view(mark), after_idx);
+        } else {
+            if (!std::distance(mark.begin(), mark.end())) {
+                return;
+            }
+
+            auto it = _currentLogPatternRange.begin();
+            size_t idx = 0;
+            while (it != _currentLogPatternRange.end()) {
+                ++it;
+                if (idx == after_idx)
+                    break;
+
+                ++idx;
+            }
+
+            _currentLogPatternRange.emplace(it, mark.begin(), mark.end());
+
+            _currentLogPattern.clear();
+            std::ranges::copy(std::views::join(_currentLogPatternRange), std::back_inserter(_currentLogPattern));
+
+            _loggerSPtr->set_pattern(_currentLogPattern);
+        }
+    }
+};
+
+static_assert(snplib_logger_c<snplib_spdlog_logger_t>);
+
+#endif
+
+}  // namespace snplib
\ No newline at end of file
diff --git a/include/snipplib/utils/snplib_utils.h b/include/snipplib/utils/snplib_utils.h
index 632355b..09e40ed 100644
--- a/include/snipplib/utils/snplib_utils.h
+++ b/include/snipplib/utils/snplib_utils.h
@@ -1,4 +1,6 @@
 #pragma once
 
 #include "snplib_hash.h"
-#include "snplib_string.h"
\ No newline at end of file
+#include "snplib_keyvalue_expr.h"
+#include "snplib_logger.h"
+#include "snplib_string.h"