LittleVGL 源码分析--src/lv_misc/lv_log.h
这是log配置信息：
/*================
* Log settings 日志设置
*===============*/
/*1: Enable the log module 启用日志模块 */
#define LV_USE_LOG 1
#if LV_USE_LOG
/* How important log should be added:
* LV_LOG_LEVEL_TRACE A lot of logs to give detailed information跟踪大量日志以提供详细信息
* LV_LOG_LEVEL_INFO Log important events重要事件
* LV_LOG_LEVEL_WARN Log if something unwanted happened but didn't cause a problem如果发生了不需要发生的事情但没有引起问题，请记录
* LV_LOG_LEVEL_ERROR Only critical issue, when the system may fail只有在系统可能出现故障时才会出现的严重问题
* LV_LOG_LEVEL_NONE Do not log anything不要记录任何内容
*/
# define LV_LOG_LEVEL LV_LOG_LEVEL_WARN
/* 1: Print the log with 'printf';
* 0: user need to register a callback with `lv_log_register_print` 用户需要使用“lv”log“register”print注册回调*/
# define LV_LOG_PRINTF 1
#endif /*LV_USE_LOG*/lv_log.h
/**
* @file lv_log.h
*
*/
#ifndef LV_LOG_H
#define LV_LOG_H
#ifdef __cplusplus
extern "C" {
#endif
/*********************
* INCLUDES
*********************/
#ifdef LV_CONF_INCLUDE_SIMPLE
#include "lv_conf.h"
#else
#include "../../../lv_conf.h"
#endif
#include
/*********************
* DEFINES
*********************/
/*Possible log level. For compatibility declare it independently from `LV_USE_LOG`*/
//可能的日志级别。为了兼容性，请独立于“LV”USE\u LOG声明它`
#define LV_LOG_LEVEL_TRACE 0 /**< A lot of logs to give detailed information*/
#define LV_LOG_LEVEL_INFO 1 /**< Log important events*/
#define LV_LOG_LEVEL_WARN 2 /**< Log if something unwanted happened but didn't caused problem*/
#define LV_LOG_LEVEL_ERROR 3 /**< Only critical issue, when the system may fail*/
#define LV_LOG_LEVEL_NONE 4 /**< Do not log anything*/
#define _LV_LOG_LEVEL_NUM 5 /**< Number of log levels */
typedef int8_t lv_log_level_t;
#if LV_USE_LOG
/**********************
* TYPEDEFS
**********************/
/**
* Log print function. Receives "Log Level", "File path", "Line number" and "Description".
* 日志打印功能。 接收“日志级别”、“文件路径”、“行号”和“说明”。
*/
typedef void (*lv_log_print_g_cb_t)(lv_log_level_t level, const char *, uint32_t, const char *);
/**********************
* GLOBAL PROTOTYPES
**********************/
/**
* Register custom print/write function to call when a log is added.
* It can format its "File path", "Line number" and "Description" as required
* and send the formatted log message to a consol or serial port.
* @param print_cb a function pointer to print a log
*注册自定义打印/写入函数以在添加日志时调用。
*它可以根据需要格式化“文件路径”、“行号”和“说明”
*并将格式化的日志消息发送到控制台或串行端口。
*/
void lv_log_register_print_cb(lv_log_print_g_cb_t print_cb);
/**
* Add a log *添加日志
* @param level the level of log. (From `lv_log_level_t` enum)
* @param file name of the file when the log added
* @param line line number in the source code where the log added
* @param dsc description of the log
*/
void lv_log_add(lv_log_level_t level, const char * file, int line, const char * dsc);
/**********************
* MACROS
**********************/
#if LV_LOG_LEVEL <= LV_LOG_LEVEL_TRACE
#define LV_LOG_TRACE(dsc) lv_log_add(LV_LOG_LEVEL_TRACE, __FILE__, __LINE__, dsc);
#else
#define LV_LOG_TRACE(dsc) \
{ \
; \
}
#endif
#if LV_LOG_LEVEL <= LV_LOG_LEVEL_INFO
#define LV_LOG_INFO(dsc) lv_log_add(LV_LOG_LEVEL_INFO, __FILE__, __LINE__, dsc);
#else
#define LV_LOG_INFO(dsc) \
{ \
; \
}
#endif
#if LV_LOG_LEVEL <= LV_LOG_LEVEL_WARN
#define LV_LOG_WARN(dsc) lv_log_add(LV_LOG_LEVEL_WARN, __FILE__, __LINE__, dsc);
#else
#define LV_LOG_WARN(dsc) \
{ \
; \
}
#endif
#if LV_LOG_LEVEL <= LV_LOG_LEVEL_ERROR
#define LV_LOG_ERROR(dsc) lv_log_add(LV_LOG_LEVEL_ERROR, __FILE__, __LINE__, dsc);
#else
#define LV_LOG_ERROR(dsc) \
{ \
; \
}
#endif
#else /*LV_USE_LOG*/
/*Do nothing if `LV_USE_LOG 0`*/
#define lv_log_add(level, file, line, dsc) \
{ \
; \
}
#define LV_LOG_TRACE(dsc) \
{ \
; \
}
#define LV_LOG_INFO(dsc) \
{ \
; \
}
#define LV_LOG_WARN(dsc) \
{ \
; \
}
#define LV_LOG_ERROR(dsc) \
{ \
; \
}
#endif /*LV_USE_LOG*/
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /*LV_LOG_H*/
lv_log.c
/**
* @file lv_log.c
*
*/
#include "lv_log.h"
#if LV_USE_LOG
#if LV_LOG_PRINTF
#include
#endif
static lv_log_print_g_cb_t custom_print_cb;//系统回掉函数
void lv_log_register_print_cb(lv_log_print_g_cb_t print_cb)
{
custom_print_cb = print_cb;//将自己定义的log回掉函数赋给系统回掉函数
}
void lv_log_add(lv_log_level_t level, const char * file, int line, const char * dsc)
{
if(level >= _LV_LOG_LEVEL_NUM) return; /*Invalid level*/
if(level >= LV_LOG_LEVEL) {
#if LV_LOG_PRINTF //判断
static const char * lvl_prefix[] = {"Trace", "Info", "Warn", "Error"};
printf("%s: %s \t(%s #%d)\n", lvl_prefix[level], dsc, file, line);//调用printf
#else
if(custom_print_cb) custom_print_cb(level, file, line, dsc);//调用自己定义的
#endif
}
}
总结：
log的函数有两个
注册自己的log函数：
lv_log_register_print_cb(lv_log_print_g_cb_t print_cb)
打印函数
lv_log_add(lv_log_level_t level, const char * file, int line, const char * dsc) level： LV_LOG_LEVEL_TRACE 0 /**< A lot of logs to give detailed information*/
LV_LOG_LEVEL_INFO 1 /**< Log important events*/
LV_LOG_LEVEL_WARN 2 /**< Log if something unwanted happened but didn't caused problem*/
LV_LOG_LEVEL_ERROR 3 /**< Only critical issue, when the system may fail*/
LV_LOG_LEVEL_NONE 4 /**< Do not log anything*/
_LV_LOG_LEVEL_NUM 5 /**< Number of log levels */
下面的宏定义直接打印：
#if LV_LOG_LEVEL <= LV_LOG_LEVEL_TRACE
#define LV_LOG_TRACE(dsc) lv_log_add(LV_LOG_LEVEL_TRACE, __FILE__, __LINE__, dsc);
#else
#define LV_LOG_TRACE(dsc) \
{ \
; \
}
#endif
#if LV_LOG_LEVEL <= LV_LOG_LEVEL_INFO
#define LV_LOG_INFO(dsc) lv_log_add(LV_LOG_LEVEL_INFO, __FILE__, __LINE__, dsc);
#else
#define LV_LOG_INFO(dsc) \
{ \
; \
}
#endif
#if LV_LOG_LEVEL <= LV_LOG_LEVEL_WARN
#define LV_LOG_WARN(dsc) lv_log_add(LV_LOG_LEVEL_WARN, __FILE__, __LINE__, dsc);
#else
#define LV_LOG_WARN(dsc) \
{ \
; \
}
#endif
#if LV_LOG_LEVEL <= LV_LOG_LEVEL_ERROR
#define LV_LOG_ERROR(dsc) lv_log_add(LV_LOG_LEVEL_ERROR, __FILE__, __LINE__, dsc);
#else
#define LV_LOG_ERROR(dsc) \
{ \
; \
}
#endif
#else /*LV_USE_LOG*/
/*Do nothing if `LV_USE_LOG 0`*/
#define lv_log_add(level, file, line, dsc) \
{ \
; \
}
#define LV_LOG_TRACE(dsc) \
{ \
; \
}
#define LV_LOG_INFO(dsc) \
{ \
; \
}
#define LV_LOG_WARN(dsc) \
{ \
; \
}
#define LV_LOG_ERROR(dsc) \
{ \
; \
}
#endif /*LV_USE_LOG*/