Merge pull request 'allow nf7::Exception to take dynamic string' (#136) from feat/124-exception-dstr into main

Reviewed-on: #136

iface/CMakeLists.txt

@@ -9,8 +9,8 @@ target_sources(nf7_iface
     common/exception.cc
     version.cc
   PUBLIC
-    common/dealer.hh
     common/container.hh
+    common/dealer.hh
     common/exception.hh
     common/future.hh
     common/leak_detector.hh
@@ -32,8 +32,9 @@ target_sources(nf7_iface
 add_executable(nf7_iface_test)
 target_sources(nf7_iface_test
   PRIVATE
-    common/dealer_test.cc
     common/container_test.cc
+    common/dealer_test.cc
+    common/exception_test.cc
     common/future_test.cc
     common/leak_detector_test.cc
     common/observer_test.cc

iface/common/exception.hh

@@ -4,6 +4,8 @@
 #include <exception>
 #include <ostream>
 #include <source_location>
+#include <string>
+#include <variant>
 
 namespace nf7 {
 
@@ -14,6 +16,10 @@ class Exception : public std::exception, std::nested_exception {
       const char*          what,
       std::source_location location = std::source_location::current()) :
       what_(what), location_(location) { }
+  explicit Exception(
+      const std::string&   what,
+      std::source_location location = std::source_location::current()) :
+      what_(what), location_(location) { }
 
   void RethrowNestedIf() const {
     if (auto ptr = nested_ptr()) {
@@ -21,11 +27,15 @@ class Exception : public std::exception, std::nested_exception {
     }
   }
 
-  const char* what() const noexcept override { return what_; }
+  const char* what() const noexcept override {
+    return std::holds_alternative<const char*>(what_)?
+        std::get<const char*>(what_):
+        std::get<std::string>(what_).c_str();
+  }
   const std::source_location& location() const noexcept { return location_; }
 
  private:
-  const char* what_;
+  std::variant<const char*, std::string> what_;
   std::source_location location_;
 };
 

iface/common/exception_test.cc

@@ -0,0 +1,20 @@
+// No copyright
+#include "iface/common/exception.hh"
+
+#include <gtest/gtest.h>
+
+#include <string>
+
+
+TEST(Exception, WithStaticMessage) {
+  static const char* kMsg = "helloworld";
+  nf7::Exception sut {kMsg};
+  EXPECT_EQ(sut.what(), kMsg);
+}
+
+TEST(Exception, WithDynamicMessage) {
+  static const char* kMsg = "helloworld";
+  nf7::Exception sut {std::string {kMsg}};
+  EXPECT_STREQ(sut.what(), kMsg);
+  EXPECT_NE(sut.what(), kMsg);
+}