/* Copyright (c) 2018, 2022, Oracle and/or its affiliates.

This program is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License, version 2.0,

as published by the Free Software Foundation.

This program is also distributed with certain software (including

but not limited to OpenSSL) that is licensed under separate terms,

as designated in a particular file or component or in included license

documentation. The authors of MySQL hereby grant you an additional

permission to link the program and your derivative works with the

separately licensed software that they have included with MySQL.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

GNU General Public License, version 2.0, for more details.

You should have received a copy of the GNU General Public License

along with this program; if not, write to the Free Software

Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */

#include "sql-common/json_syntax_check.h"

#include "my_rapidjson_size_t.h" // IWYU pragma: keep

#include <assert.h>

#include <rapidjson/error/en.h>

#include <rapidjson/error/error.h>

#include <rapidjson/memorystream.h>

#include <rapidjson/reader.h>

#include <string>

#include <utility>

#include "my_sys.h"

#include "mysqld_error.h"

bool Syntax_check_handler::StartObject() {

m_too_deep_error_raised = check_json_depth(++m_depth, m_depth_handler);

return !m_too_deep_error_raised;

}

bool Syntax_check_handler::EndObject(rapidjson::SizeType) {

--m_depth;

return true;

}

bool Syntax_check_handler::StartArray() {

m_too_deep_error_raised = check_json_depth(++m_depth, m_depth_handler);

return !m_too_deep_error_raised;

}

bool Syntax_check_handler::EndArray(rapidjson::SizeType) {

--m_depth;

return true;

}

Syntax_check_handler::Syntax_check_handler(

JsonDocumentDepthHandler m_depth_handler)

: m_depth_handler(std::move(m_depth_handler)) {}

bool is_valid_json_syntax(const char *text, size_t length, size_t *error_offset,

std::string *error_message,

const JsonDocumentDepthHandler &depth_handler) {

Syntax_check_handler handler(depth_handler);

rapidjson::Reader reader;

rapidjson::MemoryStream ms(text, length);

const bool valid = reader.Parse<rapidjson::kParseDefaultFlags>(ms, handler);

if (!valid && (error_offset != nullptr || error_message != nullptr)) {

const std::pair<std::string, size_t> error = get_error_from_reader(reader);

if (error_offset != nullptr) {

*error_offset = error.second;

}

if (error_message != nullptr) {

error_message->assign(error.first);

}

}

return valid;

}

/// The maximum number of nesting levels allowed in a JSON document.

static constexpr int JSON_DOCUMENT_MAX_DEPTH = 100;

bool check_json_depth(size_t depth, const JsonDocumentDepthHandler &handler) {

if (depth > JSON_DOCUMENT_MAX_DEPTH) {

handler();

return true;

}

return false;

}

std::pair<std::string, size_t> get_error_from_reader(

const rapidjson::Reader &reader) {

assert(reader.GetParseErrorCode() != rapidjson::kParseErrorNone);

return std::make_pair(

std::string(rapidjson::GetParseError_En(reader.GetParseErrorCode())),

reader.GetErrorOffset());

}