C++ generated code - add missing <optional> or <memory> include

Author: vaind

internal/generator/c/cgenerator.go

@@ -129,7 +129,8 @@ func (gen *CGenerator) generateBindingFile(bindingFile, headerFile string, m *mo
 		GeneratorVersion int
 		FileIdentifier   string
 		HeaderFile       string
-	}{m, generator.VersionId, fileIdentifier, filepath.Base(headerFile)}
+		Optional         string
+	}{m, generator.VersionId, fileIdentifier, filepath.Base(headerFile), gen.Optional}
 
 	var tpl *template.Template
 

internal/generator/c/templates/binding-hpp.go

@@ -31,6 +31,11 @@ var CppBindingTemplateHeader = template.Must(template.New("binding-hpp").Funcs(f
 
 #include <cstdbool>
 #include <cstdint>
+{{- if eq "std::optional" .Optional}} 
+#include <optional>
+{{- else if .Optional}}
+#include <memory>
+{{end}}
 
 #include "flatbuffers/flatbuffers.h"
 #include "objectbox.h"