sql-parser/src/utils.cpp

#include "utils.h"

#include <fmt/core.h>

#include <algorithm>
#include <fstream>
#include <map>
#include <nlohmann/json.hpp>
#include <string>
#include <vector>

using json = nlohmann::json;
using std::string;
using std::vector;

SQLParserRes parse_sql(const std::string& sql) {
    SQLParserRes res;
    // auto stdout_name = std::tmpnam(nullptr);
    // auto stderr_name = std::tmpnam(nullptr);
    auto stdout_name = "/tmp/sql-parser-stdout";
    auto stderr_name = "/tmp/sql-parser-stderr";

    auto cmd = fmt::format("xmake run sql-parser \"{}\" > {} 2> {}", sql,
                           stdout_name, stderr_name);
    res.exit_code = system(cmd.c_str());

    std::ifstream stdout_f(stdout_name);
    json stdout_j = json::parse(stdout_f);
    res.out = stdout_j;

    std::ifstream stderr_f(stderr_name);

    res.err.assign((std::istreambuf_iterator<char>(stderr_f)),
                   (std::istreambuf_iterator<char>()));

    return res;
}

ExistTables::ExistTables(const char* file_name) {
    table_file_name = file_name;
    std::ifstream ifile(table_file_name);

    if (!ifile.good()) {
        std::ofstream ofile(table_file_name);
        ofile << "{}";
        ofile.close();
    }
    ifile.close();
    read_from_file();
}
ExistTables* ExistTables::read_from_file() {
    std::ifstream f(table_file_name);
    json j = json::parse(f);
    for (auto& item : j.items()) {
        tables[item.key()] = item.value();
    }
    return this;
};

bool ExistTables::exists(const std::string& table_name) {
    return tables.find(table_name) != tables.end();
}
void ExistTables::set(const std::string& table_name, const TableCols& cols) {
    tables[table_name] = cols;
}
TableCols ExistTables::operator[](const std::string& table_name) {
    return this->get(table_name);
}
TableCols ExistTables::operator[](const std::vector<std::string>& table_names) {
    return this->get(table_names);
}
TableCols ExistTables::get(const std::string& table_name) {
    return tables[table_name];
}
TableCols ExistTables::get(const std::vector<std::string>& table_names) {
    TableCols res = {};
    for (let table_name : table_names) {
        let cols = this->get(table_name);
        res.assign(cols.begin(), cols.end());
    }
    return res;
}

optional<TableCol> ExistTables::find_col_in_tables(
    const std::vector<std::string>& table_names, const std::string col_name) {
    for (let table_name : table_names) {
        let cols = this->get(table_name);
        for (let col : cols) {
            if (col.column_name == col_name) {
                return col;
            }
        }
    }
    return nullopt;
}

void ExistTables::remove(const std::string& table_name) {
    tables.erase(table_name);
}
void ExistTables::save() {
    json j;
    for (auto& item : tables) {
        j[item.first] = item.second;
    }
    std::ofstream f(table_file_name);
    f << j.dump(2);
}

optional<TableCol> ExistTables::get_select_column_define(
    const vector<string> table_names, const json& select_col) {
    auto type = type_of(select_col);
    if (type == "identifier") {
        return this->find_col_in_tables(table_names, select_col["value"]);
    } else if (type == "int" || type == "string" || type == "float") {
        return TableCol{.column_name = select_col["value"].dump(),
                        .type = "const",
                        .data_type = type,
                        .primary_key = false};
    } else if (type == "select_all_column") {
        return TableCol{.column_name = "*",
                        .type = "select_all_column",
                        .data_type = "",
                        .primary_key = false};
    } else if (type == "table_field") {
        let curr_table_name = select_col["table"];
        let curr_field_name = select_col["field"];

        if (std::find(table_names.begin(), table_names.end(),
                      curr_table_name) == table_names.end()) {
            return nullopt;
        }
        return this->find_col_in_tables({curr_table_name}, curr_field_name);
    }
    return nullopt;
}

string select_column_get_name(const json& j) {
    let type = j["type"];
    if (type == "identifier") {
        return j["value"];
    } else if (type == "select_all_column") {
        return "select_all_column";
    } else if (type == "int" || type == "string" || type == "float") {
        return fmt::format("{}:{}", type, j["value"]);
    } else if (type == "table_field") {
        return fmt::format("{}.{}", j["table"], j["field"]);
    }
    throw std::runtime_error(
        fmt::format("无法将 json 视为 select_column: {}", j.dump(2)));
}