c_cpp 带有旋转逻辑的C语言记录器实现

Posted 2021-05-14

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

static const char* LOG_LEVEL_DEBUG = "DEBUG";
static const char* LOG_LEVEL_INFO = "INFO";
static const char* LOG_LEVEL_WARNING = "WARNING";
static const char* LOG_LEVEL_ERROR = "ERROR";

#ifdef WIN32_UTF16_PATHNAMES
# error "UTF-16 pathnames not supported"
#endif

struct logger_t {
  FILE* stream;
  char time_buf[26];
  const char* path;
  struct tm* time_info;
  unsigned rotation;
  size_t curr_size;
  size_t max_size;
  time_t log_time;
};

/**
 * sets log time according to local time.
 */
static inline void
logger_set_time(struct logger_t* log)
{
  time(&(log->log_time));
  log->time_info = localtime(&(log->log_time));
  strftime(log->time_buf, 26, "%Y-%m-%d %H:%M:%S", log->time_info);
}
/**
 * Initializes logger instance, 
 * checks if null on fopen 
 */
static int
logger_init(struct logger_t* log,
            const char* pathname, size_t max_size)
{
  char path_bin[256];
  strncpy(path_bin, log->path, 256);
  strcat(path_bin, "0");
  log->rotation = 0;
  log->stream = fopen(path_bin, "a");
  if(log->stream == NULL) return 0;
  log->curr_size = 0;
  log->max_size = max_size;
  return 1;
}

/**
 * rotating logic,
 * will increment integer at the end of file name
 */
static int
logger_check_rotation(struct logger_t* log)
{
  if(log->max_size > log->curr_size) {
    return 1;
  } else {
    size_t cur_path_len;
    char path_bin[256];
    char rot_int[12];
    strncpy(path_bin, log->path, 256);
    fclose(log->stream);
    log->rotation++;
    sprintf(rot_int, "%u", log->rotation);
    strcat(path_bin, rot_int);
    log->stream = fopen(path_bin, "a");
    if(log->stream == NULL) return 0;
    return 1;
  }
}
/**
 * method to log events, with chosen level and pre-formatted message.
 */
extern int logger_log_event(struct logger_t* log,
                             const char* level,
                             const char* restrict mes)
{
  size_t event_size;
  if(!logger_check_rotation(log)) return 0;
  logger_set_time(log);
  event_size =  strlen(log->time_buf) + strlen(level) +strlen(mes);
  log->curr_size += event_size;
  fprintf(log->stream, "%s %s %s", log->time_buf, level, mes);
  return 1;
}