MySQLDumper/library/Msd/Sql/Parser.php

<?php
/**
 * This file is part of MySQLDumper released under the GNU/GPL 2 license
 * http://www.mysqldumper.net
 *
 * @package    MySQLDumper
 * @subpackage SQL-Parser
 * @version    SVN: $Rev$
 * @author     $Author$
 */

/**
 * Class to parse MySQL queries.
 * This enables you to analyze and modify MySQL queries, which the user has entered.
 *
 * @package         MySQLDumper
 * @subpackage      SQL-Browser
 */
class Msd_Sql_Parser implements Iterator
{
    /**
     * Saves the raw MySQL Query.
     *
     * @var string
     */
    private $_rawQuery = null;

    /**
     * Parsed MySQL statements.
     *
     * @var array
     */
    private $_parsedStatements = array();

    /**
     * Holds the summary of the parsing process.
     * The summary contains the count of each statement in the query.
     *
     * @var array
     */
    private $_parsingSummary = array();

    /**
     * MySQL comment types.
     *
     * @var array
     */
    protected $_sqlComments = array(
        '--' => "\n", '/*' => '*/', '/*!' => '*/'
    );

    /**
     * Whether to save debug output
     *
     * @var bool
     */
    private $_debug = false;

    /**
     * Debug output buffer
     *
     * @var string
     */
    private $_debugOutput = '';


    /**
     * Class constructor.
     * Creates a new instance of the MySQL parser and optionally assign the raw MySQL query.
     *
     * @param Msd_Sql_Object $sqlObject SQL-Object holding the data to be parsed
     * @param bool           $debug     If turned on, detection of queries is logged
     */
    public function __construct(Msd_Sql_Object $sqlObject, $debug = false)
    {
        $this->_sql = $sqlObject;
        $this->_debug = $debug;
    }

    /**
     * Parses a raw MySQL query.
     * This could include more than one MySQL statement.
     *
     * @throws Msd_Sql_Parser_Exception
     *
     * @return void
     */
    public function parse()
    {
        // get first characters to extract the kind of query we have to process
        $statementCounter = 0;
        while ($this->_sql->hasMoreToProcess()) {
            $this->_sql->movePointerToNextCommand();
            $endOfCommand = $this->_sql->getPosition(' ');
            $sqlQuery = $this->_sql->getData($endOfCommand);
            //echo "<br>Query beginn: ".$sqlQuery;

            $parts = explode(' ', $sqlQuery);
            $statement = strtolower($parts[0]);
            // check for comments or conditional comments
            $commentCheck = substr($sqlQuery, 0, 2);
            if (isset($this->_sqlComments[$commentCheck]) || substr($statement, 0, 3) == '/*!') {
                $statement = 'Comment';
            }

            $foundStatement = $this->_parseStatement($this->_sql, ucwords($statement));
            if ($this->_debug) {
                $this->_debugOutput .= '<br />Extracted statement: '.$foundStatement;
            }
            $this->_parsedStatements[] = $foundStatement;
            $statementCounter++;
            // increment query type counter
            if (!isset($this->_parsingSummary[$statement])) {
                $this->_parsingSummary[$statement] = 0;
            }
            $this->_parsingSummary[$statement]++;
        }
    }

    /**
     * Creates an instance of a statement parser class and invokes statement parsing.
     *
     * @throws Msd_Sql_Parser_Exception
     *
     * @param Msd_Sql_Object $sqlObject MySQL statement to parse
     * @param string         $statement Parser class to use
     *
     * @return array
     */
    private function _parseStatement(Msd_Sql_Object $sqlObject, $statement)
    {
        $statementPath = '/Msd/Sql/Parser/Statement/' . $statement;
        if ($statement !== 'Select') die("Not implemented yet: ".$statement);
        if (!file_exists(LIBRARY_PATH . $statementPath . '.php')) {
            throw new Msd_Sql_Parser_Exception("Can't find statement class for statement: " . $statement);
        }
        $statementClass = 'Msd_Sql_Parser_Statement_' . $statement;
        $parserObject = new $statementClass;
        return $parserObject->parse($sqlObject);
    }

    /**
     * Returns the array with the parsed statements.
     *
     * @return array
     */
    public function getParsedStatements()
    {
        return $this->_parsedStatements;
    }

    /**
     * Returns the parsing summary.
     *
     * @return array
     */
    public function getSummary()
    {
        return $this->_parsingSummary;
    }

    /**
     * Rewind (reset) the internal pointer position af the parsed statements array.
     *
     * @return mixed
     */
    public function rewind()
    {
        return reset($this->_parsedStatements);
    }

    /**
     * Return the current value af the parsed statements array.
     *
     * @return mixed
     */
    public function current()
    {
        return current($this->_parsedStatements);
    }

    /**
     * Return the current key af the parsed statements array.
     *
     * @return mixed
     */
    public function key()
    {
        return key($this->_parsedStatements);
    }

    /**
     * Move the internal pointer af the parsed statements array to the next position.
     *
     * @return mixed
     */
    public function next()
    {
        return next($this->_parsedStatements);
    }

    /**
     * Validates the internal pointer position af the parsed statements array.
     *
     * @return bool
     */
    public function valid()
    {
        return key($this->_parsedStatements) !== null;
    }

    /**
     * Get debug output buffer
     *
     * @return array
     */
    public function getDebugOutput()
    {
        return $this->_debugOutput;
    }
}