add liblokinet custom logger

include/lokinet/lokinet_misc.h

@@ -21,6 +21,12 @@ extern "C"
   int EXPORT
   lokinet_log_level(const char*);
 
+  typedef void (*lokinet_logger_func)(const char*, void*);
+
+  /// set a custom logger function
+  void EXPORT
+  lokinet_set_logger(lokinet_logger_func func, void* user);
+
   /// @brief take in hex and turn it into base32z
   /// @return value must be free()'d later
   char* EXPORT

llarp/lokinet_shared.cpp

@@ -22,6 +22,33 @@
 
 namespace
 {
+  struct Logger : public llarp::ILogStream
+  {
+    lokinet_logger_func func;
+    void* user;
+
+    explicit Logger(lokinet_logger_func _func, void* _user) : func{_func}, user{_user}
+    {}
+
+    void
+    PreLog(std::stringstream&, llarp::LogLevel, const char*, int, const std::string&) const override
+    {}
+
+    void
+    Print(llarp::LogLevel, const char*, const std::string& msg) override
+    {
+      func(msg.c_str(), user);
+    }
+
+    void
+    PostLog(std::stringstream&) const override{};
+
+    void
+    ImmediateFlush() override{};
+
+    void Tick(llarp_time_t) override{};
+  };
+
   struct Context : public llarp::Context
   {
     using llarp::Context::Context;
@@ -1028,4 +1055,10 @@ extern "C"
     }
     return EINVAL;
   }
+
+  void EXPORT
+  lokinet_set_logger(lokinet_logger_func func, void* user)
+  {
+    llarp::LogContext::Instance().logStream.reset(new Logger{func, user});
+  }
 }