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#if MYSQL_6_10
// Copyright © 2009, 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 Externals.MySql.Data.MySqlClient;using System;using System.Collections.Generic;using System.IO;using System.Linq;using System.Text;
namespace Externals.MySql.Data.Common{ internal class QueryNormalizer { private static readonly List<string> Keywords = new List<string>(); private readonly List<Token> _tokens = new List<Token>(); private int _pos; private string _fullSql; private string _queryType;
static QueryNormalizer() { Keywords.AddRange(Resources.Keywords); }
public string QueryType => _queryType;
public string Normalize(string sql) { _tokens.Clear(); StringBuilder newSql = new StringBuilder(); _fullSql = sql;
TokenizeSql(sql); DetermineStatementType(_tokens); ProcessMathSymbols(_tokens); CollapseValueLists(_tokens); CollapseInLists(_tokens); CollapseWhitespace(_tokens);
foreach (Token t in _tokens.Where(t => t.Output)) newSql.Append(t.Text);
return newSql.ToString(); }
private void DetermineStatementType(List<Token> tok) { foreach (Token t in tok.Where(t => t.Type == TokenType.Keyword)) { _queryType = t.Text.ToUpperInvariant(); break; } }
/// <summary>
/// Mark - or + signs that are unary ops as no output
/// </summary>
/// <param name="tok"></param>
private static void ProcessMathSymbols(List<Token> tok) { Token lastToken = null;
foreach (Token t in tok) { if (t.Type == TokenType.Symbol && (t.Text == "-" || t.Text == "+")) { if (lastToken != null && lastToken.Type != TokenType.Number && lastToken.Type != TokenType.Identifier && (lastToken.Type != TokenType.Symbol || lastToken.Text != ")")) t.Output = false; } if (t.IsRealToken) lastToken = t; } }
private static void CollapseWhitespace(List<Token> tok) { Token lastToken = null;
foreach (Token t in tok) { if (t.Output && t.Type == TokenType.Whitespace && lastToken != null && lastToken.Type == TokenType.Whitespace) { t.Output = false; } if (t.Output) lastToken = t; } }
private void CollapseValueLists(List<Token> tok) { int pos = -1; while (++pos < tok.Count) { Token t = tok[pos]; if (t.Type != TokenType.Keyword) continue; if (!t.Text.StartsWith("VALUE", StringComparison.OrdinalIgnoreCase)) continue; CollapseValueList(tok, ref pos); } }
private void CollapseValueList(List<Token> tok, ref int pos) { List<int> parenIndices = new List<int>();
// this while loop will find all closing parens in this value list
while (true) { // find the close ')'
while (++pos < tok.Count) { if (tok[pos].Type == TokenType.Symbol && tok[pos].Text == ")") break; if (pos == tok.Count - 1) break; } parenIndices.Add(pos);
// now find the next "real" token
while (++pos < tok.Count) if (tok[pos].IsRealToken) break; if (pos == tok.Count) break;
if (tok[pos].Text == ",") continue; pos--; break; }
// if we only have 1 value then we don't collapse
if (parenIndices.Count < 2) return; int index = parenIndices[0]; tok[++index] = new Token(TokenType.Whitespace, " "); tok[++index] = new Token(TokenType.Comment, "/* , ... */"); index++;
// now mark all the other tokens as no output
while (index <= parenIndices[parenIndices.Count - 1]) tok[index++].Output = false; }
private void CollapseInLists(List<Token> tok) { int pos = -1; while (++pos < tok.Count) { Token t = tok[pos]; if (t.Type != TokenType.Keyword) continue; if (t.Text != "IN") continue; CollapseInList(tok, ref pos); } }
private static Token GetNextRealToken(List<Token> tok, ref int pos) { while (++pos < tok.Count) { if (tok[pos].IsRealToken) return tok[pos]; } return null; }
private static void CollapseInList(List<Token> tok, ref int pos) { Token t = GetNextRealToken(tok, ref pos); // Debug.Assert(t.Text == "(");
if (t == null) return;
// if the first token is a keyword then we likely have a
// SELECT .. IN (SELECT ...)
t = GetNextRealToken(tok, ref pos); if (t == null || t.Type == TokenType.Keyword) return;
int start = pos; // first find all the tokens that make up the in list
while (++pos < tok.Count) { t = tok[pos]; if (t.Type == TokenType.CommandComment) return; if (!t.IsRealToken) continue; if (t.Text == "(") return; if (t.Text == ")") break; } int stop = pos;
for (int i = stop; i > start; i--) tok.RemoveAt(i); tok.Insert(++start, new Token(TokenType.Whitespace, " ")); tok.Insert(++start, new Token(TokenType.Comment, "/* , ... */")); tok.Insert(++start, new Token(TokenType.Whitespace, " ")); tok.Insert(++start, new Token(TokenType.Symbol, ")")); }
private void TokenizeSql(string sql) { _pos = 0;
while (_pos < sql.Length) { char c = sql[_pos]; if (LetterStartsComment(c) && ConsumeComment()) continue; if (Char.IsWhiteSpace(c)) ConsumeWhitespace(); else if (c == '\'' || c == '\"' || c == '`') ConsumeQuotedToken(c); else if (!IsSpecialCharacter(c)) ConsumeUnquotedToken(); else ConsumeSymbol(); } }
private bool LetterStartsComment(char c) { return c == '#' || c == '/' || c == '-'; }
private bool IsSpecialCharacter(char c) { return !Char.IsLetterOrDigit(c) && c != '$' && c != '_' && c != '.'; }
private bool ConsumeComment() { char c = _fullSql[_pos]; // make sure the comment starts correctly
if (c == '/' && ((_pos + 1) >= _fullSql.Length || _fullSql[_pos + 1] != '*')) return false; if (c == '-' && ((_pos + 2) >= _fullSql.Length || _fullSql[_pos + 1] != '-' || _fullSql[_pos + 2] != ' ')) return false;
string endingPattern = "\n"; if (c == '/') endingPattern = "*/";
int startingIndex = _pos;
int index = _fullSql.IndexOf(endingPattern, _pos); if (index == -1) index = _fullSql.Length - 1; else index += endingPattern.Length; string comment = _fullSql.Substring(_pos, index - _pos); if (comment.StartsWith("/*!", StringComparison.Ordinal)) _tokens.Add(new Token(TokenType.CommandComment, comment)); _pos = index; return true; }
private void ConsumeSymbol() { char c = _fullSql[_pos++]; _tokens.Add(new Token(TokenType.Symbol, c.ToString())); }
private void ConsumeQuotedToken(char c) { bool escaped = false; int start = _pos; _pos++; while (_pos < _fullSql.Length) { char x = _fullSql[_pos];
if (x == c && !escaped) break;
if (escaped) escaped = false; else if (x == '\\') escaped = true; _pos++; } _pos++; _tokens.Add(c == '\'' ? new Token(TokenType.String, "?") : new Token(TokenType.Identifier, _fullSql.Substring(start, _pos - start))); }
private void ConsumeUnquotedToken() { int startPos = _pos; while (_pos < _fullSql.Length && !IsSpecialCharacter(_fullSql[_pos])) _pos++; string word = _fullSql.Substring(startPos, _pos - startPos); double v; if (Double.TryParse(word, out v)) _tokens.Add(new Token(TokenType.Number, "?")); else { Token t = new Token(TokenType.Identifier, word); if (IsKeyword(word)) { t.Type = TokenType.Keyword; t.Text = t.Text.ToUpperInvariant(); } _tokens.Add(t); } }
private void ConsumeWhitespace() { _tokens.Add(new Token(TokenType.Whitespace, " ")); while (_pos < _fullSql.Length && Char.IsWhiteSpace(_fullSql[_pos])) _pos++; }
private static bool IsKeyword(string word) { return Keywords.Contains(word.ToUpperInvariant()); } }
internal class Token { public TokenType Type; public string Text; public bool Output;
public Token(TokenType type, string text) { Type = type; Text = text; Output = true; }
public bool IsRealToken => Type != TokenType.Comment && Type != TokenType.CommandComment && Type != TokenType.Whitespace && Output; }
internal enum TokenType { Keyword, String, Number, Symbol, Identifier, Comment, CommandComment, Whitespace }}
#endif
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