86 lines
2.6 KiB
C++
86 lines
2.6 KiB
C++
// Copyright 2022 Memgraph Ltd.
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//
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// Use of this software is governed by the Business Source License
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// included in the file licenses/BSL.txt; by using this file, you agree to be bound by the terms of the Business Source
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// License, and you may not use this file except in compliance with the Business Source License.
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//
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// As of the Change Date specified in that file, in accordance with
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// the Business Source License, use of this software will be governed
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// by the Apache License, Version 2.0, included in the file
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// licenses/APL.txt.
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#pragma once
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#include <string>
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#include "antlr4-runtime.h"
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#include "utils/exceptions.hpp"
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#include "parser/opencypher/generated/MemgraphCypher.h"
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#include "parser/opencypher/generated/MemgraphCypherLexer.h"
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#include "utils/concepts.hpp"
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namespace memgraph::frontend::opencypher {
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class SyntaxException : public utils::BasicException {
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public:
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using utils::BasicException::BasicException;
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SyntaxException() : SyntaxException("") {}
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};
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/**
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* Generates openCypher AST
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* This thing must me a class since parser.cypher() returns pointer and there is
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* no way for us to get ownership over the object.
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*/
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enum class ParserOpTag : uint8_t {
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CYPHER, EXPRESSION
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};
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template<ParserOpTag Tag = ParserOpTag::CYPHER>
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class Parser {
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public:
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/**
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* @param query incoming query that has to be compiled into query plan
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* the first step is to generate AST
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*/
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Parser(const std::string query) : query_(std::move(query)) {
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parser_.removeErrorListeners();
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parser_.addErrorListener(&error_listener_);
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if constexpr(Tag == ParserOpTag::CYPHER) {
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tree_ = parser_.cypher();
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}
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else {
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tree_ = parser_.expression();
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}
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if (parser_.getNumberOfSyntaxErrors()) {
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throw SyntaxException(error_listener_.error_);
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}
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}
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auto tree() { return tree_; }
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private:
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class FirstMessageErrorListener : public antlr4::BaseErrorListener {
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void syntaxError(antlr4::Recognizer *, antlr4::Token *, size_t line, size_t position, const std::string &message,
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std::exception_ptr) override {
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if (error_.empty()) {
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error_ = "line " + std::to_string(line) + ":" + std::to_string(position + 1) + " " + message;
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}
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}
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public:
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std::string error_;
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};
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FirstMessageErrorListener error_listener_;
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std::string query_;
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antlr4::ANTLRInputStream input_{query_};
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antlropencypher::MemgraphCypherLexer lexer_{&input_};
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antlr4::CommonTokenStream tokens_{&lexer_};
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// generate ast
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antlropencypher::MemgraphCypher parser_{&tokens_};
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antlr4::tree::ParseTree *tree_ = nullptr;
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};
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} // namespace memgraph::frontend::opencypher
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