source: Ballon/out/artifacts/geisa_artifact/WEB-INF/lib/mysql-connector-java-5.1.21/src/com/mysql/jdbc/EscapeTokenizer.java @ 766

/*
 Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
 

  The MySQL Connector/J 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



 */
package com.mysql.jdbc;

/**
 * EscapeTokenizer breaks up an SQL statement into SQL and escape code parts.
 * 
 * @author Mark Matthews
 */
public class EscapeTokenizer {
        // ~ Instance fields
        // --------------------------------------------------------

        private int bracesLevel = 0;

        private boolean emittingEscapeCode = false;

        private boolean inComment = false;

        private boolean inQuotes = false;

        private char lastChar = 0;

        private char lastLastChar = 0;

        private int pos = 0;

        private char quoteChar = 0;

        private boolean sawVariableUse = false;

        private String source = null;

        private int sourceLength = 0;

        // ~ Constructors
        // -----------------------------------------------------------

        /**
         * Creates a new EscapeTokenizer object.
         * 
         * @param s
         *            the string to tokenize
         */
        public EscapeTokenizer(String s) {
                this.source = s;
                this.sourceLength = s.length();
                this.pos = 0;
        }

        // ~ Methods
        // ----------------------------------------------------------------

        /**
         * 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() {
                StringBuffer tokenBuf = new StringBuffer();

                if (this.emittingEscapeCode) {
                        tokenBuf.append("{"); //$NON-NLS-1$
                        this.emittingEscapeCode = false;
                }

                for (; this.pos < this.sourceLength; this.pos++) {
                        char c = this.source.charAt(this.pos);

                        // Detect variable usage

                        if (!this.inQuotes && c == '@') {
                                this.sawVariableUse = true;
                        }

                        if ((c == '\'' || c == '"') && !inComment) {
                                if (this.inQuotes && c == quoteChar) {
                                        if (this.pos + 1 < this.sourceLength) {
                                                if (this.source.charAt(this.pos + 1) == quoteChar) {
                                                        // Doubled-up quote escape, if the first quote isn't already escaped
                                                        if (this.lastChar != '\\') {
                                                                tokenBuf.append(quoteChar);
                                                                tokenBuf.append(quoteChar);
                                                                this.pos++;
                                                                continue;
                                                        }
                                                }
                                        }
                                }
                                if (this.lastChar != '\\') {
                                        if (this.inQuotes) {
                                                if (this.quoteChar == c) {
                                                        this.inQuotes = false;
                                                }
                                        } else {
                                                this.inQuotes = true;
                                                this.quoteChar = c;
                                        }
                                } else if (this.lastLastChar == '\\') {
                                        if (this.inQuotes) {
                                                if (this.quoteChar == c) {
                                                        this.inQuotes = false;
                                                }
                                        } else {
                                                this.inQuotes = true;
                                                this.quoteChar = c;
                                        }
                                }

                                tokenBuf.append(c);
                        } else if (c == '-') {
                                if ((this.lastChar == '-')
                                                && ((this.lastLastChar != '\\') && !this.inQuotes)) {
                                        this.inComment = true;
                                }

                                tokenBuf.append(c);
                        } else if ((c == '\n') || (c == '\r')) {
                                this.inComment = false;

                                tokenBuf.append(c);
                        } else if (c == '{') {
                                if (this.inQuotes || this.inComment) {
                                        tokenBuf.append(c);
                                } else {
                                        this.bracesLevel++;

                                        if (this.bracesLevel == 1) {
                                                this.pos++;
                                                this.emittingEscapeCode = true;

                                                return tokenBuf.toString();
                                        }

                                        tokenBuf.append(c);
                                }
                        } else if (c == '}') {
                                tokenBuf.append(c);

                                if (!this.inQuotes && !this.inComment) {
                                        this.lastChar = c;

                                        this.bracesLevel--;

                                        if (this.bracesLevel == 0) {
                                                this.pos++;

                                                return tokenBuf.toString();
                                        }
                                }
                        } else {
                                tokenBuf.append(c);
                        }

                        this.lastLastChar = this.lastChar;
                        this.lastChar = c;
                }

                return tokenBuf.toString();
        }

        boolean sawVariableUse() {
                return this.sawVariableUse;
        }
}