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<?php
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/**
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 * Abstract class for a set of proprietary modules that clean up (tidy)
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 * poorly written HTML.
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 * @todo Figure out how to protect some of these methods/properties
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 */
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class HTMLPurifier_HTMLModule_Tidy extends HTMLPurifier_HTMLModule
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{
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    /**
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     * List of supported levels.
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     * Index zero is a special case "no fixes" level.
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     * @type array
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     */
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    public $levels = array(0 => 'none', 'light', 'medium', 'heavy');
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    /**
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     * Default level to place all fixes in.
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     * Disabled by default.
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     * @type string
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     */
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    public $defaultLevel = null;
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    /**
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     * Lists of fixes used by getFixesForLevel().
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     * Format is:
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     *      HTMLModule_Tidy->fixesForLevel[$level] = array('fix-1', 'fix-2');
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     * @type array
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     */
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    public $fixesForLevel = array(
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        'light' => array(),
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        'medium' => array(),
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        'heavy' => array()
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    );
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    /**
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     * Lazy load constructs the module by determining the necessary
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     * fixes to create and then delegating to the populate() function.
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     * @param HTMLPurifier_Config $config
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     * @todo Wildcard matching and error reporting when an added or
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     *       subtracted fix has no effect.
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     */
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    public function setup($config)
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    {
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        // create fixes, initialize fixesForLevel
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        $fixes = $this->makeFixes();
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        $this->makeFixesForLevel($fixes);
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        // figure out which fixes to use
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        $level = $config->get('HTML.TidyLevel');
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        $fixes_lookup = $this->getFixesForLevel($level);
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        // get custom fix declarations: these need namespace processing
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        $add_fixes = $config->get('HTML.TidyAdd');
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        $remove_fixes = $config->get('HTML.TidyRemove');
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        foreach ($fixes as $name => $fix) {
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            // needs to be refactored a little to implement globbing
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            if (isset($remove_fixes[$name]) ||
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                (!isset($add_fixes[$name]) && !isset($fixes_lookup[$name]))) {
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                unset($fixes[$name]);
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            }
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        }
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        // populate this module with necessary fixes
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        $this->populate($fixes);
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    }
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    /**
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     * Retrieves all fixes per a level, returning fixes for that specific
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     * level as well as all levels below it.
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     * @param string $level level identifier, see $levels for valid values
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     * @return array Lookup up table of fixes
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     */
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    public function getFixesForLevel($level)
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    {
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        if ($level == $this->levels[0]) {
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            return array();
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        }
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        $activated_levels = array();
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        for ($i = 1, $c = count($this->levels); $i < $c; $i++) {
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            $activated_levels[] = $this->levels[$i];
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            if ($this->levels[$i] == $level) {
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                break;
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            }
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        }
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        if ($i == $c) {
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            trigger_error(
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                'Tidy level ' . htmlspecialchars($level) . ' not recognized',
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                E_USER_WARNING
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            );
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            return array();
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        }
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        $ret = array();
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        foreach ($activated_levels as $level) {
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            foreach ($this->fixesForLevel[$level] as $fix) {
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                $ret[$fix] = true;
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            }
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        }
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        return $ret;
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    }
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    /**
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     * Dynamically populates the $fixesForLevel member variable using
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     * the fixes array. It may be custom overloaded, used in conjunction
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     * with $defaultLevel, or not used at all.
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     * @param array $fixes
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     */
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    public function makeFixesForLevel($fixes)
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    {
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        if (!isset($this->defaultLevel)) {
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            return;
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        }
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        if (!isset($this->fixesForLevel[$this->defaultLevel])) {
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            trigger_error(
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                'Default level ' . $this->defaultLevel . ' does not exist',
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                E_USER_ERROR
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            );
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            return;
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        }
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        $this->fixesForLevel[$this->defaultLevel] = array_keys($fixes);
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    }
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    /**
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     * Populates the module with transforms and other special-case code
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     * based on a list of fixes passed to it
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     * @param array $fixes Lookup table of fixes to activate
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     */
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    public function populate($fixes)
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    {
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        foreach ($fixes as $name => $fix) {
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            // determine what the fix is for
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            list($type, $params) = $this->getFixType($name);
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            switch ($type) {
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                case 'attr_transform_pre':
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                case 'attr_transform_post':
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                    $attr = $params['attr'];
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                    if (isset($params['element'])) {
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                        $element = $params['element'];
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                        if (empty($this->info[$element])) {
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                            $e = $this->addBlankElement($element);
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                        } else {
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                            $e = $this->info[$element];
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                        }
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                    } else {
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                        $type = "info_$type";
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                        $e = $this;
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                    }
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                    $e->{$type}[$attr] = $fix;
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                    break;
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                case 'tag_transform':
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                    $this->info_tag_transform[$params['element']] = $fix;
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                    break;
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                case 'child':
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                case 'content_model_type':
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                    $element = $params['element'];
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                    if (empty($this->info[$element])) {
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                        $e = $this->addBlankElement($element);
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                    } else {
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                        $e = $this->info[$element];
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                    }
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                    $e->$type = $fix;
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                    break;
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                default:
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                    trigger_error("Fix type $type not supported", E_USER_ERROR);
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                    break;
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            }
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        }
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    }
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    /**
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     * Parses a fix name and determines what kind of fix it is, as well
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     * as other information defined by the fix
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     * @param $name String name of fix
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     * @return array(string $fix_type, array $fix_parameters)
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     * @note $fix_parameters is type dependant, see populate() for usage
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     *       of these parameters
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     */
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    public function getFixType($name)
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    {
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        // parse it
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        $property = $attr = null;
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        if (strpos($name, '#') !== false) {
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            list($name, $property) = explode('#', $name);
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        }
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        if (strpos($name, '@') !== false) {
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            list($name, $attr) = explode('@', $name);
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        }
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        // figure out the parameters
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        $params = array();
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        if ($name !== '') {
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            $params['element'] = $name;
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        }
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        if (!is_null($attr)) {
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            $params['attr'] = $attr;
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        }
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        // special case: attribute transform
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        if (!is_null($attr)) {
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            if (is_null($property)) {
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                $property = 'pre';
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            }
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            $type = 'attr_transform_' . $property;
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            return array($type, $params);
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        }
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        // special case: tag transform
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        if (is_null($property)) {
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            return array('tag_transform', $params);
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        }
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        return array($property, $params);
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    }
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    /**
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     * Defines all fixes the module will perform in a compact
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     * associative array of fix name to fix implementation.
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     * @return array
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     */
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    public function makeFixes()
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    {
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        return array();
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    }
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}
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// vim: et sw=4 sts=4