content: /*
   * Copyright (c) 2002, 2020, 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.
   *
   * Without limiting anything contained in the foregoing, this file, which is
   * part of MySQL Connector/J, is also subject to the Universal FOSS Exception,
   * version 1.0, a copy of which can be found at
   * http://oss.oracle.com/licenses/universal-foss-exception.
   *
   * 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
   */
  
  package com.mysql.cj.util;
  
  /**
   * EscapeTokenizer breaks up an SQL statement into SQL and escape code parts.
   */
  public class EscapeTokenizer {
      private static final char CHR_ESCAPE = '\\';
      private static final char CHR_SGL_QUOTE = '\'';
      private static final char CHR_DBL_QUOTE = '"';
      private static final char CHR_LF = '\n';
      private static final char CHR_CR = '\r';
      private static final char CHR_COMMENT = '-';
      private static final char CHR_BEGIN_TOKEN = '{';
      private static final char CHR_END_TOKEN = '}';
      private static final char CHR_VARIABLE = '@';
  
      private String source = null;
      private int sourceLength = 0;
      private int pos = 0;
  
      private boolean emittingEscapeCode = false;
      private boolean sawVariableUse = false;
      private int bracesLevel = 0;
      private boolean inQuotes = false;
      private char quoteChar = 0;
  
      /**
       * Creates a new EscapeTokenizer object.
       * 
       * @param source
       *            the string to tokenize
       */
      public EscapeTokenizer(String source) {
          this.source = source;
          this.sourceLength = source.length();
          this.pos = 0;
      }
  
      /**
       * Does this tokenizer have more tokens available?
       * 
       * @return if this tokenizer has more tokens available
       */
      public synchronized boolean hasMoreTokens() {
          return (this.pos < this.sourceLength);
      }
  
      /**
       * Returns the next token
       * 
       * @return the next token.
       */
      public synchronized String nextToken() {
          StringBuilder tokenBuf = new StringBuilder();
          boolean backslashEscape = false;
  
          if (this.emittingEscapeCode) {
              // Previous token ended at the beginning of an escape code, so this token must start with '{'
              tokenBuf.append("{");
              this.emittingEscapeCode = false;
          }
  
          for (; this.pos < this.sourceLength; this.pos++) {
              char c = this.source.charAt(this.pos);
  
              // process escape char: (\)
              if (c == CHR_ESCAPE) {
                  tokenBuf.append(c);
                  backslashEscape = !backslashEscape;
                  continue;
              }
  
              // process quotes: ('|")
              if ((c == CHR_SGL_QUOTE || c == CHR_DBL_QUOTE) && !backslashEscape) {
                  tokenBuf.append(c);
                  if (this.inQuotes) {
                      if (c == this.quoteChar) {
                          // look ahead for doubled quote
                          if ((this.pos + 1 < this.sourceLength) && (this.source.charAt(this.pos + 1) == this.quoteChar)) {
                              tokenBuf.append(c);
                              this.pos++; // consume following char '\'' or '"'
                          } else {
                              this.inQuotes = false;
                          }
                      }
                  } else {
                      this.inQuotes = true;
                      this.quoteChar = c;
                  }
                  continue;
              }
  
              // process new line: (\n|\r)
              if ((c == CHR_LF) || (c == CHR_CR)) {
                  tokenBuf.append(c);
                  backslashEscape = false;
                  continue;
              }
  
              if (!this.inQuotes && !backslashEscape) {
                  // process comments: (--)
                  if (c == CHR_COMMENT) {
                      tokenBuf.append(c);
                      // look ahead for double hyphen
                      if ((this.pos + 1 < this.sourceLength) && (this.source.charAt(this.pos + 1) == CHR_COMMENT)) {
                          // consume following chars until new line or end of string
                          while (++this.pos < this.sourceLength && c != CHR_LF && c != CHR_CR) {
                              c = this.source.charAt(this.pos);
                              tokenBuf.append(c);
                          }
                          this.pos--;
                      }
                      continue;
                  }
  
                  // process begin token: ({)
                  if (c == CHR_BEGIN_TOKEN) {
                      this.bracesLevel++;
                      if (this.bracesLevel == 1) {
                          this.emittingEscapeCode = true;
                          this.pos++; // consume char '{' before returning
                          return tokenBuf.toString();
                      }
                      tokenBuf.append(c);
                      continue;
                  }
  
                  // process end token: (})
                  if (c == CHR_END_TOKEN) {
                      tokenBuf.append(c);
                      this.bracesLevel--;
                      if (this.bracesLevel == 0) {
                          this.pos++; // consume char '}' before returning
                          return tokenBuf.toString();
                      }
                      continue;
                  }
  
                  // detect variable usage: (@)
                  if (c == CHR_VARIABLE) {
                      this.sawVariableUse = true;
                  }
              }
  
              tokenBuf.append(c);
              backslashEscape = false;
          }
  
          return tokenBuf.toString();
      }
  
      /**
       * Returns true if a variable reference was found. Note that this information isn't accurate until finishing to
       * process all tokens from source String. It also can't be used as per token basis.
       * 
       * @return true if a variable reference was found.
       */
      public boolean sawVariableUse() {
          return this.sawVariableUse;
      }
  }
  