CSort

public function __construct($modelClass=null)
{
    $this->modelClass=$modelClass;
}

public function applyOrder($criteria)
{
    $order=$this->getOrderBy($criteria);
    if(!empty($order))
    {
        if(!empty($criteria->order))
            $criteria->order.=', ';
        $criteria->order.=$order;
    }
}

protected function createLink($attribute,$label,$url,$htmlOptions)
{
    return CHtml::link($label,$url,$htmlOptions);
}

public function createUrl($controller,$directions)
{
    $sorts=array();
    foreach($directions as $attribute=>$descending)
        $sorts[]=$descending ? $attribute.$this->separators[1].$this->descTag : $attribute;
    $params=$this->params===null ? $_GET : $this->params;
    $params[$this->sortVar]=implode($this->separators[0],$sorts);
    return $controller->createUrl($this->route,$params);
}

public function getDirection($attribute)
{
    $this->getDirections();
    return isset($this->_directions[$attribute]) ? $this->_directions[$attribute] : null;
}

public function getDirections()
{
    if($this->_directions===null)
    {
        $this->_directions=array();
        if(isset($_GET[$this->sortVar]) && is_string($_GET[$this->sortVar]))
        {
            $attributes=explode($this->separators[0],$_GET[$this->sortVar]);
            foreach($attributes as $attribute)
            {
                if(($pos=strrpos($attribute,$this->separators[1]))!==false)
                {
                    $descending=substr($attribute,$pos+1)===$this->descTag;
                    if($descending)
                        $attribute=substr($attribute,0,$pos);
                }
                else
                    $descending=false;

                if(($this->resolveAttribute($attribute))!==false)
                {
                    $this->_directions[$attribute]=$descending;
                    if(!$this->multiSort)
                        return $this->_directions;
                }
            }
        }
        if($this->_directions===array() && is_array($this->defaultOrder))
            $this->_directions=$this->defaultOrder;
    }
    return $this->_directions;
}

protected function getModel($className)
{
    return CActiveRecord::model($className);
}

public function getOrderBy($criteria=null)
{
    $directions=$this->getDirections();
    if(empty($directions))
        return is_string($this->defaultOrder) ? $this->defaultOrder : '';
    else
    {
        if($this->modelClass!==null)
            $schema=$this->getModel($this->modelClass)->getDbConnection()->getSchema();
        $orders=array();
        foreach($directions as $attribute=>$descending)
        {
            $definition=$this->resolveAttribute($attribute);
            if(is_array($definition))
            {
                if($descending)
                    $orders[]=isset($definition['desc']) ? (is_array($definition['desc']) ? implode(', ',$definition['desc']) : $definition['desc']) : $attribute.' DESC';
                else
                    $orders[]=isset($definition['asc']) ? (is_array($definition['asc']) ? implode(', ',$definition['asc']) : $definition['asc']) : $attribute;
            }
            elseif($definition!==false)
            {
                $attribute=$definition;
                if(isset($schema))
                {
                    if(($pos=strpos($attribute,'.'))!==false)
                        $attribute=$schema->quoteTableName(substr($attribute,0,$pos)).'.'.$schema->quoteColumnName(substr($attribute,$pos+1));
                    else
                        $attribute=($criteria===null || $criteria->alias===null ? $this->getModel($this->modelClass)->getTableAlias(true) : $schema->quoteTableName($criteria->alias)).'.'.$schema->quoteColumnName($attribute);
                }
                $orders[]=$descending?$attribute.' DESC':$attribute;
            }
        }
        return implode(', ',$orders);
    }
}

public function link($attribute,$label=null,$htmlOptions=array())
{
    if($label===null)
        $label=$this->resolveLabel($attribute);
    if(($definition=$this->resolveAttribute($attribute))===false)
        return $label;
    $directions=$this->getDirections();
    if(isset($directions[$attribute]))
    {
        $class=$directions[$attribute] ? 'desc' : 'asc';
        if(isset($htmlOptions['class']))
            $htmlOptions['class'].=' '.$class;
        else
            $htmlOptions['class']=$class;
        $descending=!$directions[$attribute];
        unset($directions[$attribute]);
    }
    elseif(is_array($definition) && isset($definition['default']))
        $descending=$definition['default']==='desc';
    else
        $descending=false;

    if($this->multiSort)
        $directions=array_merge(array($attribute=>$descending),$directions);
    else
        $directions=array($attribute=>$descending);

    $url=$this->createUrl(Yii::app()->getController(),$directions);

    return $this->createLink($attribute,$label,$url,$htmlOptions);
}

public function resolveAttribute($attribute)
{
    if($this->attributes!==array())
        $attributes=$this->attributes;
    elseif($this->modelClass!==null)
        $attributes=$this->getModel($this->modelClass)->attributeNames();
    else
        return false;
    foreach($attributes as $name=>$definition)
    {
        if(is_string($name))
        {
            if($name===$attribute)
                return $definition;
        }
        elseif($definition==='*')
        {
            if($this->modelClass!==null && $this->getModel($this->modelClass)->hasAttribute($attribute))
                return $attribute;
        }
        elseif($definition===$attribute)
            return $attribute;
    }
    return false;
}

public function resolveLabel($attribute)
{
    $definition=$this->resolveAttribute($attribute);
    if(is_array($definition))
    {
        if(isset($definition['label']))
            return $definition['label'];
    }
    elseif(is_string($definition))
        $attribute=$definition;
    if($this->modelClass!==null)
        return $this->getModel($this->modelClass)->getAttributeLabel($attribute);
    else
        return $attribute;
}