use nonblocking write for serial

lib/log/GWLog.cpp

@@ -1,25 +1,38 @@
 #include "GwLog.h"
 
-GwLog::GwLog(bool logSerial, int level){
-    this->logSerial=logSerial;
+class DefaultLogWriter: public GwLogWriter{
+    public:
+        virtual ~DefaultLogWriter(){};
+        virtual void write(const char *data){
+            Serial.print(data);
+        }
+};
+
+GwLog::GwLog(int level, GwLogWriter *writer){
     logLevel=level;
+    if (writer == NULL) writer=new DefaultLogWriter();
+    this->writer=writer;
 }
 void GwLog::logString(const char *fmt,...){
+    if (! writer) return;
     va_list args;
     va_start(args,fmt);
     vsnprintf(buffer,99,fmt,args);
-    if (logSerial){
-        Serial.print("LOG: ");
-        Serial.println(buffer);
-    }
+    writer->write(prefix.c_str());
+    writer->write(buffer);
+    writer->write("\n");
 }
 void GwLog::logDebug(int level,const char *fmt,...){
     if (level > logLevel) return;
+    if (! writer) return;
     va_list args;
     va_start(args,fmt);
     vsnprintf(buffer,99,fmt,args);
-    if (logSerial){
-        Serial.print("LOG: ");
-        Serial.println(buffer);
-    }
+    writer->write(prefix.c_str());
+    writer->write(buffer);
+    writer->write("\n");
+}
+void GwLog::setWriter(GwLogWriter *writer){
+    if (this->writer) delete this->writer;
+    this->writer=writer;
 }

lib/log/GwLog.h

@@ -1,17 +1,25 @@
 #ifndef _GWLOG_H
 #define _GWLOG_H
 #include <Arduino.h>
+
+class GwLogWriter{
+    public:
+        virtual ~GwLogWriter(){}
+        virtual void write(const char *data)=0;
+};
 class GwLog{
     private:
         char buffer[100];
-        bool logSerial=false;
         int logLevel=1;
+        GwLogWriter *writer;
     public:
         static const int LOG=1;
         static const int ERROR=0;
         static const int DEBUG=3;
         static const int TRACE=2;
-        GwLog(bool logSerial,int level=LOG);
+        String prefix="LOG:";
+        GwLog(int level=LOG, GwLogWriter *writer=NULL);
+        void setWriter(GwLogWriter *writer);
         void logString(const char *fmt,...);
         void logDebug(int level, const char *fmt,...);
         int isActive(int level){return level <= logLevel;};