first commit

utils/logger/vp_log_file_writer.h

@@ -0,0 +1,49 @@
+#pragma once
+
+#include <string>
+#include <fstream>
+#include <chrono>
+#include <experimental/filesystem>
+
+#include "../vp_utils.h"
+
+namespace vp_utils {
+    // log file writer, write log to local file. auto create new log file bye date.
+    // NOT thread safe, MUST use in single thread.
+    class vp_log_file_writer
+    {
+    private:
+        // ready to go
+        bool inited = false;
+        
+        // root dir for log saving
+        std::string log_dir;
+        // log file name template, such as `<year>-<mon>-<day>.txt`, refer to vp_utils::time_format(...) for rule details
+        std::string log_file_name_template;
+
+        // file handle
+        std::ofstream log_writer;
+        // get valid log file name including path, name and extension
+        std::string create_valid_log_file_name();
+
+        // current log day (1 ~ 31)
+        int log_day = 0;
+
+        // get day of now
+        int get_now_day();
+
+        #define NOW std::chrono::system_clock::now()
+    public:
+        vp_log_file_writer();
+        ~vp_log_file_writer();
+        
+        // write log
+        void write(std::string log);
+
+        // initialize writer
+        void init(std::string log_dir, std::string log_file_name_template);
+
+        // for << operator
+        vp_log_file_writer& operator<<(std::string log);
+    };
+}