// Copyright 2016 The SwiftShader Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef COMPILER_PREPROCESSOR_MACRO_EXPANDER_H_
#define COMPILER_PREPROCESSOR_MACRO_EXPANDER_H_

#include <memory>
#include <vector>

#include "Lexer.h"
#include "Macro.h"
#include "pp_utils.h"

namespace pp
{

class Diagnostics;
struct SourceLocation;

class MacroExpander : public Lexer
{
public:
	MacroExpander(Lexer *lexer, MacroSet *macroSet, Diagnostics *diagnostics, bool parseDefined, int allowedMacroExpansionDepth);
	~MacroExpander() override;

	void lex(Token *token) override;

private:
	PP_DISALLOW_COPY_AND_ASSIGN(MacroExpander);

	void getToken(Token *token);
	void ungetToken(const Token &token);
	bool isNextTokenLeftParen();

	bool pushMacro(std::shared_ptr<Macro> macro, const Token &identifier);
	void popMacro();

	bool expandMacro(const Macro &macro, const Token &identifier, std::vector<Token> *replacements);

	typedef std::vector<Token> MacroArg;
	bool collectMacroArgs(const Macro &macro,
	                      const Token &identifier,
	                      std::vector<MacroArg> *args,
	                      SourceLocation *closingParenthesisLocation);
	void replaceMacroParams(const Macro &macro,
	                        const std::vector<MacroArg> &args,
	                        std::vector<Token> *replacements);

	struct MacroContext
	{
		MacroContext();
		~MacroContext();
		bool empty() const;
		const Token &get();
		void unget();

		std::shared_ptr<Macro> macro;
		std::size_t index;
		std::vector<Token> replacements;
	};

	Lexer *mLexer;
	MacroSet *mMacroSet;
	Diagnostics *mDiagnostics;
	const bool mParseDefined;

	std::unique_ptr<Token> mReserveToken;
	std::vector<MacroContext *> mContextStack;
	size_t mTotalTokensInContexts;

	int mAllowedMacroExpansionDepth;

	bool mDeferReenablingMacros;
	std::vector<std::shared_ptr<Macro>> mMacrosToReenable;

	class ScopedMacroReenabler;
};

}  // namespace pp
#endif  // COMPILER_PREPROCESSOR_MACROEXPANDER_H_