apewer-dotnet/Apewer.Source/Externals/MySql.Data-6.10.9/MySqlClient/Common/MySqlTokenizer.cs

#if MYSQL_6_10

// Copyright ?2004, 2016, Oracle and/or its affiliates.  All rights reserved.
//
// MySQL Connector/NET is licensed under the terms of the GPLv2
// <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most 
// MySQL Connectors. There are special exceptions to the terms and 
// conditions of the GPLv2 as it is applied to this software, see the 
// FLOSS License Exception
// <http://www.mysql.com/about/legal/licensing/foss-exception.html>.
//
// This program is free software; you can redistribute it and/or modify 
// it under the terms of the GNU General Public License as published 
// by the Free Software Foundation; version 2 of the License.
//
// 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 
// 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

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Text;

namespace Externals.MySql.Data.Common
{
    internal class MySqlTokenizer
    {
        private string _sql;

        public MySqlTokenizer()
        {
            BackslashEscapes = true;
            MultiLine = true;
            Position = 0;
        }

        public MySqlTokenizer(string input)
          : this()
        {
            _sql = input;
        }

        #region Properties

        public string Text
        {
            get { return _sql; }
            set { _sql = value; Position = 0; }
        }

        public bool AnsiQuotes { get; set; }

        public bool BackslashEscapes { get; set; }

        public bool MultiLine { get; set; }

        public bool SqlServerMode { get; set; }

        public bool Quoted { get; private set; }

        public bool IsComment { get; private set; }

        public int StartIndex { get; set; }

        public int StopIndex { get; set; }

        public int Position { get; set; }

        public bool ReturnComments { get; set; }

        #endregion

        public List<string> GetAllTokens()
        {
            List<string> tokens = new List<string>();
            string token = NextToken();
            while (token != null)
            {
                tokens.Add(token);
                token = NextToken();
            }
            return tokens;
        }

        public string NextToken()
        {
            while (FindToken())
            {
                string token = _sql.Substring(StartIndex, StopIndex - StartIndex);
                return token;
            }
            return null;
        }

        public static bool IsParameter(string s)
        {
            if (String.IsNullOrEmpty(s)) return false;
            if (s[0] == '?') return true;
            return s.Length > 1 && s[0] == '@' && s[1] != '@';
        }

        public string NextParameter()
        {
            while (FindToken())
            {
                if ((StopIndex - StartIndex) < 2) continue;
                char c1 = _sql[StartIndex];
                char c2 = _sql[StartIndex + 1];
                if (c1 == '?' ||
                    (c1 == '@' && c2 != '@'))
                    return _sql.Substring(StartIndex, StopIndex - StartIndex);
            }
            return null;
        }

        public bool FindToken()
        {
            IsComment = Quoted = false;  // reset our flags
            StartIndex = StopIndex = -1;

            while (Position < _sql.Length)
            {
                char c = _sql[Position++];
                if (Char.IsWhiteSpace(c)) continue;

                if (c == '`' || c == '\'' || c == '"' || (c == '[' && SqlServerMode))
                    ReadQuotedToken(c);
                else if (c == '#' || c == '-' || c == '/')
                {
                    if (!ReadComment(c))
                        ReadSpecialToken();
                }
                else
                    ReadUnquotedToken();
                if (StartIndex != -1) return true;
            }
            return false;
        }

        public string ReadParenthesis()
        {
            StringBuilder sb = new StringBuilder("(");
            int start = StartIndex;
            string token = NextToken();
            while (true)
            {
                if (token == null)
                    throw new InvalidOperationException("Unable to parse SQL");
                sb.Append(token);
                if (token == ")" && !Quoted) break;
                token = NextToken();
            }
            return sb.ToString();
        }

        private bool ReadComment(char c)
        {
            // make sure the comment starts correctly
            if (c == '/' && (Position >= _sql.Length || _sql[Position] != '*')) return false;
            if (c == '-' && ((Position + 1) >= _sql.Length || _sql[Position] != '-' || _sql[Position + 1] != ' ')) return false;

            string endingPattern = "\n";
            if (_sql[Position] == '*')
                endingPattern = "*/";

            int startingIndex = Position - 1;

            int index = _sql.IndexOf(endingPattern, Position);
            if (endingPattern == "\n")
                index = _sql.IndexOf('\n', Position);
            if (index == -1)
                index = _sql.Length - 1;
            else
                index += endingPattern.Length;

            Position = index;
            if (ReturnComments)
            {
                StartIndex = startingIndex;
                StopIndex = index;
                IsComment = true;
            }
            return true;
        }

        private void CalculatePosition(int start, int stop)
        {
            StartIndex = start;
            StopIndex = stop;
            if (!MultiLine) return;
        }

        private void ReadUnquotedToken()
        {
            StartIndex = Position - 1;

            if (!IsSpecialCharacter(_sql[StartIndex]))
            {
                while (Position < _sql.Length)
                {
                    char c = _sql[Position];
                    if (Char.IsWhiteSpace(c)) break;
                    if (IsSpecialCharacter(c)) break;
                    Position++;
                }
            }

            Quoted = false;
            StopIndex = Position;
        }

        private void ReadSpecialToken()
        {
            StartIndex = Position - 1;

            Debug.Assert(IsSpecialCharacter(_sql[StartIndex]));

            StopIndex = Position;
            Quoted = false;
        }

        /// <summary>
        ///  Read a single quoted identifier from the stream
        /// </summary>
        /// <param name="quoteChar"></param>
        /// <returns></returns>
        private void ReadQuotedToken(char quoteChar)
        {
            if (quoteChar == '[')
                quoteChar = ']';
            StartIndex = Position - 1;
            bool escaped = false;

            bool found = false;
            while (Position < _sql.Length)
            {
                char c = _sql[Position];

                if (c == quoteChar && !escaped)
                {
                    found = true;
                    break;
                }

                if (escaped)
                    escaped = false;
                else if (c == '\\' && BackslashEscapes)
                    escaped = true;
                Position++;
            }
            if (found) Position++;
            Quoted = found;
            StopIndex = Position;
        }

        private bool IsQuoteChar(char c)
        {
            return c == '`' || c == '\'' || c == '\"';
        }

        private bool IsParameterMarker(char c)
        {
            return c == '@' || c == '?';
        }

        private bool IsSpecialCharacter(char c)
        {
            if (Char.IsLetterOrDigit(c) ||
                c == '$' || c == '_' || c == '.') return false;
            if (IsParameterMarker(c)) return false;
            return true;
        }
    }
}

#endif