use std::string_view en validation functions

This increases performance as std::string (often) requires dynamic memory
allocation.

Author: cmnrd

include/reactor-cpp/assert.hh

@@ -38,10 +38,10 @@ using EnvPhase = Environment::Phase;
 
 class ValidationError : public std::runtime_error {
 private:
-  static auto build_message(const std::string& msg) noexcept -> std::string;
+  static auto build_message(std::string_view msg) noexcept -> std::string;
 
 public:
-  explicit ValidationError(const std::string& msg)
+  explicit ValidationError(const std::string_view msg)
       : std::runtime_error(build_message(msg)) {}
 };
 
@@ -56,7 +56,7 @@ inline void print_debug_backtrace() {
 }
 #endif
 
-constexpr inline void validate([[maybe_unused]] bool condition, [[maybe_unused]] const std::string& message) {
+constexpr inline void validate([[maybe_unused]] bool condition, [[maybe_unused]] const std::string_view message) {
   if constexpr (runtime_validation) { // NOLINT
     if (!condition) {
 #ifdef __linux__

lib/assert.cc

@@ -10,7 +10,7 @@
 
 namespace reactor {
 
-auto ValidationError::build_message(const std::string& msg) noexcept -> std::string {
+auto ValidationError::build_message(const std::string_view msg) noexcept -> std::string {
   std::stringstream string_stream;
   string_stream << "Validation Error! \"" << msg << "\"";
   return string_stream.str();