/common/libraries/plugin/htmlpurifier/library/HTMLPurifier/Lexer/PEARSax3.php

<?php



/**

 * Proof-of-concept lexer that uses the PEAR package XML_HTMLSax3 to parse HTML.

 *

 * PEAR, not suprisingly, also has a SAX parser for HTML.  I don't know

 * very much about implementation, but it's fairly well written.  However, that

 * abstraction comes at a price: performance. You need to have it installed,

 * and if the API changes, it might break our adapter. Not sure whether or not

 * it's UTF-8 aware, but it has some entity parsing trouble (in all areas,

 * text and attributes).

 *

 * Quite personally, I don't recommend using the PEAR class, and the defaults

 * don't use it. The unit tests do perform the tests on the SAX parser too, but

 * whatever it does for poorly formed HTML is up to it.

 *

 * @todo Generalize so that XML_HTMLSax is also supported.

 *

 * @warning Entity-resolution inside attributes is broken.

 */



class HTMLPurifier_Lexer_PEARSax3 extends HTMLPurifier_Lexer

{

    

    /**

     * Internal accumulator array for SAX parsers.

     */

    protected $tokens = array();

    protected $last_token_was_empty;

    

    private $parent_handler;

    private $stack = array();



    public function tokenizeHTML($string, $config, $context)

    {

        

        $this->tokens = array();

        $this->last_token_was_empty = false;

        

        $string = $this->normalize($string, $config, $context);

        

        $this->parent_handler = set_error_handler(array($this, 'muteStrictErrorHandler'));

        

        $parser = new XML_HTMLSax3();

        $parser->set_object($this);

        $parser->set_element_handler('openHandler', 'closeHandler');

        $parser->set_data_handler('dataHandler');

        $parser->set_escape_handler('escapeHandler');

        

        // doesn't seem to work correctly for attributes

        $parser->set_option('XML_OPTION_ENTITIES_PARSED', 1);

        

        $parser->parse($string);

        

        restore_error_handler();

        

        return $this->tokens;

    

    }



    /**

     * Open tag event handler, interface is defined by PEAR package.

     */

    public function openHandler(&$parser, $name, $attrs, $closed)

    {

        // entities are not resolved in attrs

        foreach ($attrs as $key => $attr)

        {

            $attrs[$key] = $this->parseData($attr);

        }

        if ($closed)

        {

            $this->tokens[] = new HTMLPurifier_Token_Empty($name, $attrs);

            $this->last_token_was_empty = true;

        }

        else

        {

            $this->tokens[] = new HTMLPurifier_Token_Start($name, $attrs);

        }

        $this->stack[] = $name;

        return true;

    }



    /**

     * Close tag event handler, interface is defined by PEAR package.

     */

    public function closeHandler(&$parser, $name)

    {

        // HTMLSax3 seems to always send empty tags an extra close tag

        // check and ignore if you see it:

        // [TESTME] to make sure it doesn't overreach

        if ($this->last_token_was_empty)

        {

            $this->last_token_was_empty = false;

            return true;

        }

        $this->tokens[] = new HTMLPurifier_Token_End($name);

        if (! empty($this->stack))

            array_pop($this->stack);

        return true;

    }



    /**

     * Data event handler, interface is defined by PEAR package.

     */

    public function dataHandler(&$parser, $data)

    {

        $this->last_token_was_empty = false;

        $this->tokens[] = new HTMLPurifier_Token_Text($data);

        return true;

    }



    /**

     * Escaped text handler, interface is defined by PEAR package.

     */

    public function escapeHandler(&$parser, $data)

    {

        if (strpos($data, '--') === 0)

        {

            // remove trailing and leading double-dashes

            $data = substr($data, 2);

            if (strlen($data) >= 2 && substr($data, - 2) == "--")

            {

                $data = substr($data, 0, - 2);

            }

            if (isset($this->stack[sizeof($this->stack) - 1]) && $this->stack[sizeof($this->stack) - 1] == "style")

            {

                $this->tokens[] = new HTMLPurifier_Token_Text($data);

            }

            else

            {

                $this->tokens[] = new HTMLPurifier_Token_Comment($data);

            }

            $this->last_token_was_empty = false;

        }

        // CDATA is handled elsewhere, but if it was handled here:

        //if (strpos($data, '[CDATA[') === 0) {

        //    $this->tokens[] = new HTMLPurifier_Token_Text(

        //        substr($data, 7, strlen($data) - 9) );

        //}

        return true;

    }



    /**

     * An error handler that mutes strict errors

     */

    public function muteStrictErrorHandler($errno, $errstr, $errfile = null, $errline = null, $errcontext = null)

    {

        if ($errno == E_STRICT)

            return;

        return call_user_func($this->parent_handler, $errno, $errstr, $errfile, $errline, $errcontext);

    }



}



// vim: et sw=4 sts=4