Mark type-erased classes as final and hold const Concept

Author: wravery

doc/awaitable.md

@@ -8,7 +8,7 @@ specifically a type-erased `graphql::service::await_async` class in
 [GraphQLService.h](../include/graphqlservice/GraphQLService.h):
 ```cpp
 // Type-erased awaitable.
-class await_async : public coro::suspend_always
+class await_async final
 {
 private:
 	struct Concept
@@ -31,17 +31,17 @@ public:
 
 	// Default to immediate synchronous execution.
 	await_async()
-		: _pimpl { std::static_pointer_cast<Concept>(
+		: _pimpl { std::static_pointer_cast<const Concept>(
 			std::make_shared<Model<coro::suspend_never>>(std::make_shared<coro::suspend_never>())) }
 	{
 	}
 
 	// Implicitly convert a std::launch parameter used with std::async to an awaitable.
 	await_async(std::launch launch)
 		: _pimpl { ((launch & std::launch::async) == std::launch::async)
-				? std::static_pointer_cast<Concept>(std::make_shared<Model<await_worker_thread>>(
+				? std::static_pointer_cast<const Concept>(std::make_shared<Model<await_worker_thread>>(
 					std::make_shared<await_worker_thread>()))
-				: std::static_pointer_cast<Concept>(std::make_shared<Model<coro::suspend_never>>(
+				: std::static_pointer_cast<const Concept>(std::make_shared<Model<coro::suspend_never>>(
 					std::make_shared<coro::suspend_never>())) }
 	{
 	}

doc/json.md

@@ -46,7 +46,7 @@ to some other output mechanism, without building a single string buffer for the
 document in memory. For example, you might use this to write directly to a buffered IPC pipe
 or network connection:
 ```cpp
-class Writer
+class Writer final
 {
 private:
 	struct Concept
@@ -71,7 +71,7 @@ private:
 public:
 	template <class T>
 	Writer(std::unique_ptr<T> writer)
-		: _concept { std::static_pointer_cast<Concept>(
+		: _concept { std::static_pointer_cast<const Concept>(
 			std::make_shared<Model<T>>(std::move(writer))) }
 	{
 	}

include/graphqlservice/GraphQLResponse.h

@@ -269,7 +269,7 @@ GRAPHQLRESPONSE_EXPORT IdType Value::release<IdType>();
 
 using AwaitableValue = internal::Awaitable<Value>;
 
-class Writer
+class Writer final
 {
 private:
 	struct Concept
@@ -357,7 +357,7 @@ class Writer
 public:
 	template <class T>
 	Writer(std::unique_ptr<T> writer)
-		: _concept { std::static_pointer_cast<Concept>(
+		: _concept { std::static_pointer_cast<const Concept>(
 			std::make_shared<Model<T>>(std::move(writer))) }
 	{
 	}

include/graphqlservice/GraphQLService.h

@@ -177,7 +177,7 @@ struct await_worker_queue : coro::suspend_always
 };
 
 // Type-erased awaitable.
-class await_async
+class await_async final
 {
 private:
 	struct Concept

include/graphqlservice/introspection/DirectiveObject.h

@@ -12,7 +12,7 @@
 
 namespace graphql::introspection::object {
 
-class Directive
+class Directive final
 	: public service::Object
 {
 private:
@@ -73,7 +73,7 @@ class Directive
 		const std::shared_ptr<T> _pimpl;
 	};
 
-	const std::unique_ptr<Concept> _pimpl;
+	const std::unique_ptr<const Concept> _pimpl;
 
 	service::TypeNames getTypeNames() const noexcept;
 	service::ResolverMap getResolvers() const noexcept;

include/graphqlservice/introspection/EnumValueObject.h

@@ -12,7 +12,7 @@
 
 namespace graphql::introspection::object {
 
-class EnumValue
+class EnumValue final
 	: public service::Object
 {
 private:
@@ -66,7 +66,7 @@ class EnumValue
 		const std::shared_ptr<T> _pimpl;
 	};
 
-	const std::unique_ptr<Concept> _pimpl;
+	const std::unique_ptr<const Concept> _pimpl;
 
 	service::TypeNames getTypeNames() const noexcept;
 	service::ResolverMap getResolvers() const noexcept;

include/graphqlservice/introspection/FieldObject.h

@@ -12,7 +12,7 @@
 
 namespace graphql::introspection::object {
 
-class Field
+class Field final
 	: public service::Object
 {
 private:
@@ -80,7 +80,7 @@ class Field
 		const std::shared_ptr<T> _pimpl;
 	};
 
-	const std::unique_ptr<Concept> _pimpl;
+	const std::unique_ptr<const Concept> _pimpl;
 
 	service::TypeNames getTypeNames() const noexcept;
 	service::ResolverMap getResolvers() const noexcept;

include/graphqlservice/introspection/InputValueObject.h

@@ -12,7 +12,7 @@
 
 namespace graphql::introspection::object {
 
-class InputValue
+class InputValue final
 	: public service::Object
 {
 private:
@@ -66,7 +66,7 @@ class InputValue
 		const std::shared_ptr<T> _pimpl;
 	};
 
-	const std::unique_ptr<Concept> _pimpl;
+	const std::unique_ptr<const Concept> _pimpl;
 
 	service::TypeNames getTypeNames() const noexcept;
 	service::ResolverMap getResolvers() const noexcept;

include/graphqlservice/introspection/SchemaObject.h

@@ -12,7 +12,7 @@
 
 namespace graphql::introspection::object {
 
-class Schema
+class Schema final
 	: public service::Object
 {
 private:
@@ -80,7 +80,7 @@ class Schema
 		const std::shared_ptr<T> _pimpl;
 	};
 
-	const std::unique_ptr<Concept> _pimpl;
+	const std::unique_ptr<const Concept> _pimpl;
 
 	service::TypeNames getTypeNames() const noexcept;
 	service::ResolverMap getResolvers() const noexcept;

include/graphqlservice/introspection/TypeObject.h

@@ -12,7 +12,7 @@
 
 namespace graphql::introspection::object {
 
-class Type
+class Type final
 	: public service::Object
 {
 private:
@@ -108,7 +108,7 @@ class Type
 		const std::shared_ptr<T> _pimpl;
 	};
 
-	const std::unique_ptr<Concept> _pimpl;
+	const std::unique_ptr<const Concept> _pimpl;
 
 	service::TypeNames getTypeNames() const noexcept;
 	service::ResolverMap getResolvers() const noexcept;