minute_file_sink to support every 1 min file rotation

example driver code:
auto logger = spdlog::minute_logger_mt("minutes_basic_logger", "logs/min-log.txt",false,60);

include/spdlog/sinks/minute_file_sink.h

@@ -0,0 +1,208 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//File: minute_file_sink to support every 1 min file rotation.
+//Author Manoj Mallawaarachchie manoj_ws@yahoo.com / manoj@vizuamatix.com
+//example driver code:
+//auto logger = spdlog::minute_logger_mt("minutes_basic_logger", "logs/min-log.txt",false,60);
+
+#pragma once
+
+#include <spdlog/common.h>
+#include <spdlog/details/file_helper.h>
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/fmt/fmt.h>
+#include <spdlog/sinks/base_sink.h>
+#include <spdlog/details/os.h>
+#include <spdlog/details/circular_q.h>
+#include <spdlog/details/synchronous_factory.h>
+
+#include <chrono>
+#include <cstdio>
+#include <ctime>
+#include <mutex>
+#include <string>
+
+namespace spdlog {
+namespace sinks {
+
+/*
+ * Generator of Minute log file names in format basename.YYYY-MM-DD-HH-MM.ext
+ */
+struct minute_filename_calculator
+{
+    // Create filename for the form basename.YYYY-MM-DD-H-M
+    static filename_t calc_filename(const filename_t &filename, const tm &now_tm)
+    {
+        filename_t basename, ext;
+        std::tie(basename, ext) = details::file_helper::split_by_extension(filename);
+        return fmt_lib::format(SPDLOG_FILENAME_T("{}_{:04d}-{:02d}-{:02d}-{:02d}_{:02d}{}"), basename, now_tm.tm_year + 1900, now_tm.tm_mon + 1,
+            now_tm.tm_mday, now_tm.tm_hour,now_tm.tm_min,ext);//colock details define in os-inl.h
+    }
+};
+
+/*
+ * Rotating file sink based on time(minutes).
+ * If truncate != false , the created file will be truncated.
+ * If max_files > 0, retain only the last max_files and delete previous.
+ */
+template<typename Mutex, typename FileNameCalc = minute_filename_calculator>
+class minute_file_sink final : public base_sink<Mutex>
+{
+public:
+    // create hourly file sink which rotates on given time
+    minute_file_sink(
+        filename_t base_filename, bool truncate = false, uint16_t max_files = 0, const file_event_handlers &event_handlers = {})
+        : base_filename_(std::move(base_filename))
+        , file_helper_{event_handlers}
+        , truncate_(truncate)
+        , max_files_(max_files)
+        , filenames_q_()
+    {
+        auto now = log_clock::now();
+        auto filename = FileNameCalc::calc_filename(base_filename_, now_tm(now));
+        file_helper_.open(filename, truncate_);
+        remove_init_file_ = file_helper_.size() == 0;
+        rotation_tp_ = next_rotation_tp_();
+
+        if (max_files_ > 0)
+        {
+            init_filenames_q_();
+        }
+    }
+
+    filename_t filename()
+    {
+        std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+        return file_helper_.filename();
+    }
+
+protected:
+    void sink_it_(const details::log_msg &msg) override
+    {
+        auto time = msg.time;
+        bool should_rotate = time >= rotation_tp_;
+        if (should_rotate)
+        {
+            if (remove_init_file_)
+            {
+                file_helper_.close();
+                details::os::remove(file_helper_.filename());
+            }
+            auto filename = FileNameCalc::calc_filename(base_filename_, now_tm(time));
+            file_helper_.open(filename, truncate_);
+            rotation_tp_ = next_rotation_tp_();
+        }
+        remove_init_file_ = false;
+        memory_buf_t formatted;
+        base_sink<Mutex>::formatter_->format(msg, formatted);
+        file_helper_.write(formatted);
+
+        // Do the cleaning only at the end because it might throw on failure.
+        if (should_rotate && max_files_ > 0)
+        {
+            delete_old_();
+        }
+    }
+
+    void flush_() override
+    {
+        file_helper_.flush();
+    }
+
+private:
+    void init_filenames_q_()
+    {
+        using details::os::path_exists;
+
+        filenames_q_ = details::circular_q<filename_t>(static_cast<size_t>(max_files_));
+        std::vector<filename_t> filenames;
+        auto now = log_clock::now();
+        while (filenames.size() < max_files_)
+        {
+            auto filename = FileNameCalc::calc_filename(base_filename_, now_tm(now));
+            if (!path_exists(filename))
+            {
+                break;
+            }
+            filenames.emplace_back(filename);
+            now -= std::chrono::minutes(1);
+        }
+        for (auto iter = filenames.rbegin(); iter != filenames.rend(); ++iter)
+        {
+            filenames_q_.push_back(std::move(*iter));
+        }
+    }
+
+    tm now_tm(log_clock::time_point tp)
+    {
+        time_t tnow = log_clock::to_time_t(tp);
+        return spdlog::details::os::localtime(tnow);
+    }
+
+    log_clock::time_point next_rotation_tp_()
+    {
+        auto now = log_clock::now();
+        tm date = now_tm(now);
+        date.tm_min = 0;
+        date.tm_sec = 0;
+        auto rotation_time = log_clock::from_time_t(std::mktime(&date));
+        if (rotation_time > now)
+        {
+            return rotation_time;
+        }
+        return {rotation_time + std::chrono::minutes(1)};
+    }
+
+    // Delete the file N rotations ago.
+    // Throw spdlog_ex on failure to delete the old file.
+    void delete_old_()
+    {
+        using details::os::filename_to_str;
+        using details::os::remove_if_exists;
+
+        filename_t current_file = file_helper_.filename();
+        if (filenames_q_.full())
+        {
+            auto old_filename = std::move(filenames_q_.front());
+            filenames_q_.pop_front();
+            bool ok = remove_if_exists(old_filename) == 0;
+            if (!ok)
+            {
+                filenames_q_.push_back(std::move(current_file));
+                SPDLOG_THROW(spdlog_ex("Failed removing minute file " + filename_to_str(old_filename), errno));
+            }
+        }
+        filenames_q_.push_back(std::move(current_file));
+    }
+
+    filename_t base_filename_;
+    log_clock::time_point rotation_tp_;
+    details::file_helper file_helper_;
+    bool truncate_;
+    uint16_t max_files_;
+    details::circular_q<filename_t> filenames_q_;
+    bool remove_init_file_;
+};
+
+using minute_file_sink_mt = minute_file_sink<std::mutex>;
+using minute_file_sink_st = minute_file_sink<details::null_mutex>;
+
+} // namespace sinks
+
+//
+// factory functions
+//
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> minute_logger_mt(const std::string &logger_name, const filename_t &filename, bool truncate = false,
+    uint16_t max_files = 0, const file_event_handlers &event_handlers = {})
+{
+    return Factory::template create<sinks::minute_file_sink_mt>(logger_name, filename, truncate, max_files, event_handlers);
+}
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> minute_logger_st(const std::string &logger_name, const filename_t &filename, bool truncate = false,
+    uint16_t max_files = 0, const file_event_handlers &event_handlers = {})
+{
+    return Factory::template create<sinks::minute_file_sink_st>(logger_name, filename, truncate, max_files, event_handlers);
+}
+} // namespace spdlog