refine log, can be used when _srs_config is NULL.

@@ -205,6 +205,10 @@ void SrsFastLog::error(const char* tag, int context_id, const char* fmt, ...)
 int SrsFastLog::on_reload_log_tank()
 {
     int ret = ERROR_SUCCESS;
+    
+    if (!_srs_config) {
+        return ret;
+    }
 
     bool tank = log_to_file_tank;
     log_to_file_tank = _srs_config->get_log_tank_file();
@@ -229,6 +233,10 @@ int SrsFastLog::on_reload_log_level()
 {
     int ret = ERROR_SUCCESS;
     
+    if (!_srs_config) {
+        return ret;
+    }
+    
     _level = srs_get_log_level(_srs_config->get_log_level());
     
     return ret;
@@ -237,6 +245,10 @@ int SrsFastLog::on_reload_log_level()
 int SrsFastLog::on_reload_log_file()
 {
     int ret = ERROR_SUCCESS;
+    
+    if (!_srs_config) {
+        return ret;
+    }
 
     if (!log_to_file_tank) {
         return ret;
@@ -345,6 +357,10 @@ void SrsFastLog::write_log(int& fd, char *str_log, int size, int level)
 
 void SrsFastLog::open_log_file()
 {
+    if (!_srs_config) {
+        return;
+    }
+    
     std::string filename = _srs_config->get_log_file();
     
     if (filename.empty()) {

@@ -57,6 +57,8 @@ public:
 
 /**
 * we use memory/disk cache and donot flush when write log.
+* it's ok to use it without config, which will log to console, and default trace level.
+* when you want to use different level, override this classs, set the protected _level.
 */
 class SrsFastLog : public ISrsLog, public ISrsReloadHandler
 {
@@ -64,6 +66,7 @@ class SrsFastLog : public ISrsLog, public ISrsReloadHandler
 protected:
     // defined in SrsLogLevel.
     int _level;
+private:
     char* log_data;
     // log to file if specified srs_log_file
     int fd;

@@ -45,21 +45,6 @@ MockEmptyLog::~MockEmptyLog()
 {
 }
 
-int MockEmptyLog::on_reload_log_tank()
-{
-    return ERROR_SUCCESS;
-}
-
-int MockEmptyLog::on_reload_log_level()
-{
-    return ERROR_SUCCESS;
-}
-
-int MockEmptyLog::on_reload_log_file()
-{
-    return ERROR_SUCCESS;
-}
-
 void __srs_bytes_print(char* pa, int size)
 {
     for(int i = 0; i < size; i++) {

@@ -61,10 +61,6 @@ private:
 public:
     MockEmptyLog(int level);
     virtual ~MockEmptyLog();
-public:
-    virtual int on_reload_log_tank();
-    virtual int on_reload_log_level();
-    virtual int on_reload_log_file();
 };
 
 #endif