Add thread safe log prefix assignment

src/utils/log.cpp

@@ -21,6 +21,7 @@
 #include "config/user_config.hpp"
 #include "network/network_config.hpp"
 #include "utils/file_utils.hpp"
+#include "utils/tls.hpp"
 
 #include <cstdio>
 #include <ctime>
@@ -42,10 +43,21 @@
 Log::LogLevel Log::m_min_log_level = Log::LL_VERBOSE;
 bool          Log::m_no_colors     = false;
 FILE*         Log::m_file_stdout   = NULL;
-std::string   Log::m_prefix        = "";
 size_t        Log::m_buffer_size = 1;
 bool          Log::m_console_log = true;
 Synchronised<std::vector<struct Log::LineInfo> > Log::m_line_buffer;
+thread_local  char g_prefix[11] = {};
+
+// ----------------------------------------------------------------------------
+void Log::setPrefix(const char* prefix)
+{
+    size_t len = strlen(prefix);
+    if (len > 10)
+        len = 10;
+    if (len != 0)
+        memcpy(g_prefix, prefix, len);
+    g_prefix[len] = 0;
+}   // setPrefix
 
 // ----------------------------------------------------------------------------
 /** Selects background/foreground colors for the message depending on
@@ -155,9 +167,9 @@ void Log::printMessage(int level, const char *component, const char *format,
     int index = 0;
     int remaining = MAX_LENGTH;
 
-    if (!m_prefix.empty())
+    if (strlen(g_prefix) != 0)
     {
-        index += snprintf(line+index, remaining, "%s ", m_prefix.c_str());
+        index += snprintf(line+index, remaining, "%s ", g_prefix);
         remaining = MAX_LENGTH - index > 0 ? MAX_LENGTH - index : 0;
     }
 

src/utils/log.hpp

@@ -73,14 +73,11 @@ private:
         int m_level;
     };
     static Synchronised<std::vector<struct LineInfo> > m_line_buffer;
-    
+
     /** <0 if no buffered logging is to be used, otherwise this is
      ** the maximum number of lines the buffer should hold. */
     static size_t m_buffer_size;
 
-    /** An optional prefix to be printed. */
-    static std::string m_prefix;
-
     static void setTerminalColor(LogLevel level);
     static void resetTerminalColor();
     static void writeLine(const char *line, int level);
@@ -152,7 +149,8 @@ public:
     }   // disableColor
     // ------------------------------------------------------------------------
     /** Sets a prefix to be printed before each line. To disable the prefix,
-     *  set it to "". */
+     *  set it to "", max length of prefix is 10, if larger than that the
-    static void setPrefix(const std::string &prefix) { m_prefix = prefix; }
+     *  remaining characters are ignored. */
+    static void setPrefix(const char* prefix);
 };   // Log
 #endif