Refactor GraphQLService.cpp visitors into RequestLoader.*

Author: wravery

include/RequestLoader.h

@@ -0,0 +1,170 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+#pragma once
+
+#ifndef REQUESTLOADER_H
+#define REQUESTLOADER_H
+
+#include "graphqlservice/GraphQLParse.h"
+#include "graphqlservice/GraphQLService.h"
+
+namespace graphql::runtime {
+
+// ValueVisitor visits the AST and builds a response::Value representation of any value
+// hardcoded or referencing a variable in an operation.
+class ValueVisitor
+{
+public:
+	ValueVisitor(const response::Value& variables);
+
+	void visit(const peg::ast_node& value);
+
+	response::Value getValue();
+
+private:
+	void visitVariable(const peg::ast_node& variable);
+	void visitIntValue(const peg::ast_node& intValue);
+	void visitFloatValue(const peg::ast_node& floatValue);
+	void visitStringValue(const peg::ast_node& stringValue);
+	void visitBooleanValue(const peg::ast_node& booleanValue);
+	void visitNullValue(const peg::ast_node& nullValue);
+	void visitEnumValue(const peg::ast_node& enumValue);
+	void visitListValue(const peg::ast_node& listValue);
+	void visitObjectValue(const peg::ast_node& objectValue);
+
+	const response::Value& _variables;
+	response::Value _value;
+};
+
+// DirectiveVisitor visits the AST and builds a 2-level map of directive names to argument
+// name/value pairs.
+class DirectiveVisitor
+{
+public:
+	explicit DirectiveVisitor(const response::Value& variables);
+
+	void visit(const peg::ast_node& directives);
+
+	bool shouldSkip() const;
+	response::Value getDirectives();
+
+private:
+	const response::Value& _variables;
+
+	response::Value _directives;
+};
+
+// As we recursively expand fragment spreads and inline fragments, we want to accumulate the
+// directives at each location and merge them with any directives included in outer fragments to
+// build the complete set of directives for nested fragments. Directives with the same name at the
+// same location will be overwritten by the innermost fragment.
+struct FragmentDirectives
+{
+	response::Value fragmentDefinitionDirectives;
+	response::Value fragmentSpreadDirectives;
+	response::Value inlineFragmentDirectives;
+};
+
+// SelectionVisitor visits the AST and resolves a field or fragment, unless it's skipped by
+// a directive or type condition.
+class SelectionVisitor
+{
+public:
+	explicit SelectionVisitor(const service::SelectionSetParams& selectionSetParams,
+		const service::FragmentMap& fragments, const response::Value& variables,
+		const service::TypeNames& typeNames, const service::ResolverMap& resolvers, size_t count);
+
+	void visit(const peg::ast_node& selection);
+
+	std::vector<std::pair<std::string_view, std::future<service::ResolverResult>>> getValues();
+
+private:
+	void visitField(const peg::ast_node& field);
+	void visitFragmentSpread(const peg::ast_node& fragmentSpread);
+	void visitInlineFragment(const peg::ast_node& inlineFragment);
+
+	const service::ResolverContext _resolverContext;
+	const std::shared_ptr<service::RequestState>& _state;
+	const response::Value& _operationDirectives;
+	const std::optional<std::reference_wrapper<const service::field_path>> _path;
+	const std::launch _launch;
+	const service::FragmentMap& _fragments;
+	const response::Value& _variables;
+	const service::TypeNames& _typeNames;
+	const service::ResolverMap& _resolvers;
+
+	std::list<FragmentDirectives> _fragmentDirectives;
+	internal::string_view_set _names;
+	std::vector<std::pair<std::string_view, std::future<service::ResolverResult>>> _values;
+};
+
+// FragmentDefinitionVisitor visits the AST and collects all of the fragment
+// definitions in the document.
+class FragmentDefinitionVisitor
+{
+public:
+	FragmentDefinitionVisitor(const response::Value& variables);
+
+	service::FragmentMap getFragments();
+
+	void visit(const peg::ast_node& fragmentDefinition);
+
+private:
+	const response::Value& _variables;
+
+	service::FragmentMap _fragments;
+};
+
+// OperationDefinitionVisitor visits the AST and executes the one with the specified
+// operation name.
+class OperationDefinitionVisitor
+{
+public:
+	OperationDefinitionVisitor(service::ResolverContext resolverContext, std::launch launch,
+		std::shared_ptr<service::RequestState> state, const service::TypeMap& operations, response::Value&& variables,
+		service::FragmentMap&& fragments);
+
+	std::future<service::ResolverResult> getValue();
+
+	void visit(std::string_view operationType, const peg::ast_node& operationDefinition);
+
+private:
+	const service::ResolverContext _resolverContext;
+	const std::launch _launch;
+	std::shared_ptr<service::OperationData> _params;
+	const service::TypeMap& _operations;
+	std::future<service::ResolverResult> _result;
+};
+
+// SubscriptionDefinitionVisitor visits the AST collects the fields referenced in the subscription
+// at the point where we create a subscription.
+class SubscriptionDefinitionVisitor
+{
+public:
+	SubscriptionDefinitionVisitor(service::SubscriptionParams&& params, service::SubscriptionCallback&& callback,
+		service::FragmentMap&& fragments, const std::shared_ptr<service::Object>& subscriptionObject);
+
+	const peg::ast_node& getRoot() const;
+	std::shared_ptr<service::SubscriptionData> getRegistration();
+
+	void visit(const peg::ast_node& operationDefinition);
+
+private:
+	void visitField(const peg::ast_node& field);
+	void visitFragmentSpread(const peg::ast_node& fragmentSpread);
+	void visitInlineFragment(const peg::ast_node& inlineFragment);
+
+	service::SubscriptionParams _params;
+	service::SubscriptionCallback _callback;
+	service::FragmentMap _fragments;
+	const std::shared_ptr<service::Object>& _subscriptionObject;
+	service::SubscriptionName _field;
+	response::Value _arguments;
+	response::Value _fieldDirectives;
+	std::shared_ptr<service::SubscriptionData> _result;
+};
+
+} /* namespace graphql::runtime */
+
+#endif // REQUESTLOADER_H

src/CMakeLists.txt

@@ -285,6 +285,7 @@ endif()
 add_library(graphqlservice
   GraphQLService.cpp
   GraphQLSchema.cpp
+  RequestLoader.cpp
   Validation.cpp)
 add_library(cppgraphqlgen::graphqlservice ALIAS graphqlservice)
 target_link_libraries(graphqlservice PUBLIC