[cpp-libcurl] Add oneOf support

ppritchard-peer · ppritchard-peer · commit 359de667726d · 2025-08-12T10:15:09.000+01:00
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppLibcurlClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppLibcurlClientCodegen.java
@@ -68,7 +68,8 @@ public CppLibcurlClientCodegen() {
                         GlobalFeature.MultiServer
                 )
                 .includeSchemaSupportFeatures(
-                        SchemaSupportFeature.Polymorphism
+                        SchemaSupportFeature.Polymorphism,
+                        SchemaSupportFeature.oneOf
                 )
                 .excludeParameterFeatures(
                         ParameterFeature.Cookie
diff --git a/modules/openapi-generator/src/main/resources/cpp-libcurl/model-header.mustache b/modules/openapi-generator/src/main/resources/cpp-libcurl/model-header.mustache
@@ -8,6 +8,11 @@
 #ifndef {{modelHeaderGuardPrefix}}_{{classname}}_H_
 #define {{modelHeaderGuardPrefix}}_{{classname}}_H_
 
+{{#oneOf}}
+{{#-first}}
+#include <variant>
+{{/-first}}
+{{/oneOf}}
 {{^parent}}
 {{{defaultInclude}}}
 {{#isEnum}}
@@ -31,6 +36,24 @@ namespace {{this}} {
 {{#vendorExtensions.x-forward-declarations}}{{.}}
 {{/vendorExtensions.x-forward-declarations}}
 {{/vendorExtensions.x-has-forward-declarations}}
+{{#oneOf}}{{#-first}}
+class {{declspec}} {{classname}} {
+public:
+    nlohmann::json toJson() const;
+    bool fromJson(const nlohmann::json& json);
+
+    using VariantType = std::variant<{{#oneOf}}{{^-first}}, {{/-first}}{{{.}}}{{/oneOf}}>;
+
+    const VariantType& getVariant() const;
+    void setVariant(const VariantType& value);
+    void setVariant(VariantType&& value);
+
+private:
+    VariantType m_variantValue;
+};
+
+{{/-first}}{{/oneOf}}
+{{^oneOf}}
 {{#isEnum}}
 class {{declspec}} {{classname}}
     : public {{{parent}}}{{^parent}}ModelBase{{/parent}} {
@@ -62,7 +85,6 @@ private:
 };
 {{/isEnum}}
 {{^isEnum}}
-
 {{#description}}
 /// <summary>
 /// {{{description}}}
@@ -130,6 +152,7 @@ private:
 };
 
 {{/isEnum}}
+{{/oneOf}}
 
 {{#modelNamespaceDeclarations}}
 }
diff --git a/modules/openapi-generator/src/main/resources/cpp-libcurl/model-source.mustache b/modules/openapi-generator/src/main/resources/cpp-libcurl/model-source.mustache
@@ -6,12 +6,50 @@
 #include <string_view>
 {{/isNumeric}}
 {{/isEnum}}
+{{#oneOf}}
+#include <utility>
+{{/oneOf}}
 #include "{{packageName}}/model/{{classFilename}}.h"
 
 {{#modelNamespaceDeclarations}}
 namespace {{this}} {
 {{/modelNamespaceDeclarations}}
+{{#oneOf}}
+{{#-first}}
 
+const {{classname}}::VariantType& {{classname}}::getVariant() const {
+    return m_variantValue;
+}
+
+void {{classname}}::setVariant(const {{classname}}::VariantType& value) {
+    m_variantValue = value;
+}
+
+void {{classname}}::setVariant({{classname}}::VariantType&& value) {
+    m_variantValue = std::move(value);
+}
+
+bool {{classname}}::fromJson(const nlohmann::json& json) {
+    return ModelBase::fromJson(json, m_variantValue);
+}
+
+nlohmann::json {{classname}}::toJson() const {
+    nlohmann::json val = nlohmann::json::object();
+
+    std::visit([&val](const auto& arg) {
+        using T = std::decay_t<decltype(arg)>;
+        if constexpr (std::is_same_v<T, std::monostate>) {
+            val = nullptr;
+        } else {
+            val = ModelBase::toJson(arg);
+        }
+    }, m_variantValue);
+
+    return val;
+}
+{{/-first}}
+{{/oneOf}}
+{{^oneOf}}
 {{#isEnum}}
 
 namespace {
@@ -159,6 +197,7 @@ void {{classname}}::unset{{name}}() {
 {{/isInherited}}
 {{/vars}}
 {{/isEnum}}
+{{/oneOf}}
 {{#modelNamespaceDeclarations}}
 }
 {{/modelNamespaceDeclarations}}
diff --git a/modules/openapi-generator/src/main/resources/cpp-libcurl/modelbase-header.mustache b/modules/openapi-generator/src/main/resources/cpp-libcurl/modelbase-header.mustache
@@ -18,7 +18,9 @@
 #include <memory>
 #include <set>
 #include <string>
+#include <type_traits>
 #include <utility>
+#include <variant>
 #include <vector>
 
 {{#modelNamespaceDeclarations}}
@@ -51,6 +53,11 @@ public:
     static nlohmann::json toJson(const std::set<T>& val);
     template<typename T>
     static nlohmann::json toJson(const std::map<std::string, T, std::less<>>& val);
+    template<class T,
+        std::enable_if_t<std::is_member_function_pointer_v<decltype(&T::toJson)>, bool> = false>
+    static nlohmann::json toJson(const T& val) {
+        return val.toJson();
+    }
 
     static bool fromJson(const nlohmann::json& val, bool &);
     static bool fromJson(const nlohmann::json& val, float &);
@@ -61,6 +68,7 @@ public:
     static bool fromJson(const nlohmann::json& val, uint64_t &);
     static bool fromJson(const nlohmann::json& val, std::string &);
     static bool fromJson(const nlohmann::json& val, nlohmann::json &);
+    static bool fromJson(const nlohmann::json& val, const std::monostate&);
     template<typename T>
     static bool fromJson(const nlohmann::json& val, std::shared_ptr<T>&);
     template<typename T>
@@ -69,6 +77,15 @@ public:
     static bool fromJson(const nlohmann::json& val, std::set<T> &);
     template<typename T>
     static bool fromJson(const nlohmann::json& val, std::map<std::string, T, std::less<>> &);
+    template<class T,
+        std::enable_if_t<std::is_member_function_pointer_v<decltype(&T::fromJson)>, bool> = false>
+    static bool fromJson(const nlohmann::json& val, T& outVal) {
+        return outVal.fromJson(val);
+    }
+    template<size_t N, typename... Args>
+    static bool fromJson(const nlohmann::json &val, std::variant<Args...> &);
+    template<typename... Args>
+    static bool fromJson(const nlohmann::json &val, std::variant<Args...> &);
 
 private:
     bool m_IsSet{false};
@@ -168,6 +185,27 @@ bool ModelBase::fromJson(const nlohmann::json& val, std::map<std::string, T, std
     }
     return ok;
 }
+template<size_t N, typename... Args>
+bool ModelBase::fromJson([[maybe_unused]] const nlohmann::json &val,
+        [[maybe_unused]] std::variant<Args...> &outVal) {
+    if constexpr (N >= sizeof...(Args)) {
+        return false;
+    } else {
+        std::variant_alternative_t<N, std::variant<Args...>> target;
+
+        if (!ModelBase::fromJson(val, target)) {
+            return fromJson<N + 1>(val, outVal);
+        }
+
+        outVal = std::move(target);
+        return true;
+    }
+}
+template<typename... Args>
+bool ModelBase::fromJson(const nlohmann::json &val, std::variant<Args...> &outVal) {
+    /* Try each variant type in order until a successful conversion */
+    return fromJson<0>(val, outVal);
+}
 {{#modelNamespaceDeclarations}}
 }
 {{/modelNamespaceDeclarations}}
diff --git a/modules/openapi-generator/src/main/resources/cpp-libcurl/modelbase-source.mustache b/modules/openapi-generator/src/main/resources/cpp-libcurl/modelbase-source.mustache
@@ -72,6 +72,9 @@ bool ModelBase::fromJson(const nlohmann::json& val, nlohmann::json & outVal) {
     outVal = val;
     return !val.is_null();
 }
+bool ModelBase::fromJson(const nlohmann::json& val, const std::monostate&) {
+    return val.is_null();
+}
 
 {{#modelNamespaceDeclarations}}
 }
diff --git a/samples/client/petstore/cpp/libcurl/include/CppLibcurlOpenAPIClient/ModelBase.h b/samples/client/petstore/cpp/libcurl/include/CppLibcurlOpenAPIClient/ModelBase.h
@@ -28,7 +28,9 @@
 #include <memory>
 #include <set>
 #include <string>
+#include <type_traits>
 #include <utility>
+#include <variant>
 #include <vector>
 
 namespace org::openapitools::client::model {
@@ -59,6 +61,11 @@ class  ModelBase {
     static nlohmann::json toJson(const std::set<T>& val);
     template<typename T>
     static nlohmann::json toJson(const std::map<std::string, T, std::less<>>& val);
+    template<class T,
+        std::enable_if_t<std::is_member_function_pointer_v<decltype(&T::toJson)>, bool> = false>
+    static nlohmann::json toJson(const T& val) {
+        return val.toJson();
+    }
 
     static bool fromJson(const nlohmann::json& val, bool &);
     static bool fromJson(const nlohmann::json& val, float &);
@@ -69,6 +76,7 @@ class  ModelBase {
     static bool fromJson(const nlohmann::json& val, uint64_t &);
     static bool fromJson(const nlohmann::json& val, std::string &);
     static bool fromJson(const nlohmann::json& val, nlohmann::json &);
+    static bool fromJson(const nlohmann::json& val, const std::monostate&);
     template<typename T>
     static bool fromJson(const nlohmann::json& val, std::shared_ptr<T>&);
     template<typename T>
@@ -77,6 +85,15 @@ class  ModelBase {
     static bool fromJson(const nlohmann::json& val, std::set<T> &);
     template<typename T>
     static bool fromJson(const nlohmann::json& val, std::map<std::string, T, std::less<>> &);
+    template<class T,
+        std::enable_if_t<std::is_member_function_pointer_v<decltype(&T::fromJson)>, bool> = false>
+    static bool fromJson(const nlohmann::json& val, T& outVal) {
+        return outVal.fromJson(val);
+    }
+    template<size_t N, typename... Args>
+    static bool fromJson(const nlohmann::json &val, std::variant<Args...> &);
+    template<typename... Args>
+    static bool fromJson(const nlohmann::json &val, std::variant<Args...> &);
 
 private:
     bool m_IsSet{false};
@@ -176,6 +193,27 @@ bool ModelBase::fromJson(const nlohmann::json& val, std::map<std::string, T, std
     }
     return ok;
 }
+template<size_t N, typename... Args>
+bool ModelBase::fromJson([[maybe_unused]] const nlohmann::json &val,
+        [[maybe_unused]] std::variant<Args...> &outVal) {
+    if constexpr (N >= sizeof...(Args)) {
+        return false;
+    } else {
+        std::variant_alternative_t<N, std::variant<Args...>> target;
+
+        if (!ModelBase::fromJson(val, target)) {
+            return fromJson<N + 1>(val, outVal);
+        }
+
+        outVal = std::move(target);
+        return true;
+    }
+}
+template<typename... Args>
+bool ModelBase::fromJson(const nlohmann::json &val, std::variant<Args...> &outVal) {
+    /* Try each variant type in order until a successful conversion */
+    return fromJson<0>(val, outVal);
+}
 }
 
 #endif /* ORG_OPENAPITOOLS_CLIENT_MODEL_ModelBase_H_ */
diff --git a/samples/client/petstore/cpp/libcurl/src/ModelBase.cpp b/samples/client/petstore/cpp/libcurl/src/ModelBase.cpp
@@ -80,5 +80,8 @@ bool ModelBase::fromJson(const nlohmann::json& val, nlohmann::json & outVal) {
     outVal = val;
     return !val.is_null();
 }
+bool ModelBase::fromJson(const nlohmann::json& val, const std::monostate&) {
+    return val.is_null();
+}
 
 }
diff --git a/samples/client/petstore/cpp/libcurl/src/model/Category.cpp b/samples/client/petstore/cpp/libcurl/src/model/Category.cpp
@@ -14,7 +14,6 @@
 
 namespace org::openapitools::client::model {
 
-
 nlohmann::json Category::toJson() const {
     nlohmann::json val = nlohmann::json::object();
     if (m_IdIsSet) {
diff --git a/samples/client/petstore/cpp/libcurl/src/model/Order.cpp b/samples/client/petstore/cpp/libcurl/src/model/Order.cpp
@@ -14,7 +14,6 @@
 
 namespace org::openapitools::client::model {
 
-
 nlohmann::json Order::toJson() const {
     nlohmann::json val = nlohmann::json::object();
     if (m_IdIsSet) {
diff --git a/samples/client/petstore/cpp/libcurl/src/model/Pet.cpp b/samples/client/petstore/cpp/libcurl/src/model/Pet.cpp
@@ -14,7 +14,6 @@
 
 namespace org::openapitools::client::model {
 
-
 nlohmann::json Pet::toJson() const {
     nlohmann::json val = nlohmann::json::object();
     if (m_IdIsSet) {
diff --git a/samples/client/petstore/cpp/libcurl/src/model/Tag.cpp b/samples/client/petstore/cpp/libcurl/src/model/Tag.cpp
@@ -14,7 +14,6 @@
 
 namespace org::openapitools::client::model {
 
-
 nlohmann::json Tag::toJson() const {
     nlohmann::json val = nlohmann::json::object();
     if (m_IdIsSet) {
diff --git a/samples/client/petstore/cpp/libcurl/src/model/User.cpp b/samples/client/petstore/cpp/libcurl/src/model/User.cpp
@@ -14,7 +14,6 @@
 
 namespace org::openapitools::client::model {
 
-
 nlohmann::json User::toJson() const {
     nlohmann::json val = nlohmann::json::object();
     if (m_IdIsSet) {
diff --git a/samples/client/petstore/cpp/libcurl/src/model/r_ApiResponse.cpp b/samples/client/petstore/cpp/libcurl/src/model/r_ApiResponse.cpp
@@ -14,7 +14,6 @@
 
 namespace org::openapitools::client::model {
 
-
 nlohmann::json r_ApiResponse::toJson() const {
     nlohmann::json val = nlohmann::json::object();
     if (m_CodeIsSet) {

Original file line number	Diff line number	Diff line change
`@@ -68,7 +68,8 @@ public CppLibcurlClientCodegen() {`
`68`	`68`	`GlobalFeature.MultiServer`
`69`	`69`	`)`
`70`	`70`	`.includeSchemaSupportFeatures(`
`71`		`- SchemaSupportFeature.Polymorphism`
	`71`	`+ SchemaSupportFeature.Polymorphism,`
	`72`	`+ SchemaSupportFeature.oneOf`
`72`	`73`	`)`
`73`	`74`	`.excludeParameterFeatures(`
`74`	`75`	`ParameterFeature.Cookie`
Original file line number	Diff line number	Diff line change
`@@ -72,6 +72,9 @@ bool ModelBase::fromJson(const nlohmann::json& val, nlohmann::json & outVal) {`
`72`	`72`	`outVal = val;`
`73`	`73`	`return !val.is_null();`
`74`	`74`	`}`
	`75`	`+bool ModelBase::fromJson(const nlohmann::json& val, const std::monostate&) {`
	`76`	`+ return val.is_null();`
	`77`	`+}`
`75`	`78`
`76`	`79`	`{{#modelNamespaceDeclarations}}`
`77`	`80`	`}`
Original file line number	Diff line number	Diff line change
`@@ -80,5 +80,8 @@ bool ModelBase::fromJson(const nlohmann::json& val, nlohmann::json & outVal) {`
`80`	`80`	`outVal = val;`
`81`	`81`	`return !val.is_null();`
`82`	`82`	`}`
	`83`	`+bool ModelBase::fromJson(const nlohmann::json& val, const std::monostate&) {`
	`84`	`+ return val.is_null();`
	`85`	`+}`
`83`	`86`
`84`	`87`	`}`