root/trunk/framework/Web/UI/THtmlWriter.php

<?php
/**
 * THtmlWriter class file
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.pradosoft.com/
 * @copyright Copyright &copy; 2005-2008 PradoSoft
 * @license http://www.pradosoft.com/license/
 * @version $Id$
 * @package System.Web.UI
 */

/**
 * THtmlWriter class
 *
 * THtmlWriter is a writer that renders valid XHTML outputs.
 * It provides functions to render tags, their attributes and stylesheet fields.
 * Attribute and stylesheet values will be automatically HTML-encoded if
 * they require so. For example, the 'value' attribute in an input tag
 * will be encoded.
 *
 * A common usage of THtmlWriter is as the following sequence:
 * <code>
 *  $writer->addAttribute($name1,$value1);
 *  $writer->addAttribute($name2,$value2);
 *  $writer->renderBeginTag($tagName);
 *  // ... render contents enclosed within the tag here
 *  $writer->renderEndTag();
 * </code>
 * Make sure each invocation of {@link renderBeginTag} is accompanied with
 * a {@link renderEndTag} and they are properly nested, like nesting
 * tags in HTML and XHTML.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id$
 * @package System.Web.UI
 * @since 3.0
 */
class THtmlWriter extends TApplicationComponent implements ITextWriter
{
    /**
     * @var array list of tags are do not need a closing tag
     */
    private static $_simpleTags=array(
        'area'=>true,
        'base'=>true,
        'basefont'=>true,
        'bgsound'=>true,
        'col'=>true,
        'embed'=>true,
        'frame'=>true,
        'hr'=>true,
        'img'=>true,
        'input'=>true,
        'isindex'=>true,
        'link'=>true,
        'meta'=>true,
        'wbr'=>true,
    );
    /**
     * @var array list of attributes that need HTML encoding
     */
    private static $_attrEncode=array(
        'abbr'=>true,
        'accesskey'=>true,
        'alt'=>true,
        'axis'=>true,
        'background'=>true,
        'class'=>true,
        'content'=>true,
        'headers'=>true,
        'href'=>true,
        'longdesc'=>true,
        'onclick'=>true,
        'onchange'=>true,
        'src'=>true,
        'title'=>true,
        'label'=>true,
        'value'=>true
    );
    /**
     * @var array list of stylesheet attributes that need HTML encoding
     */
    private static $_styleEncode=array(
        'background-image'=>true,
        'list-style-image'=>true
    );
    /**
     * @var array list of attributes to be rendered for a tag
     */
    private $_attributes=array();
    /**
     * @var array list of openning tags
     */
    private $_openTags=array();
    /**
     * @var array list of style attributes
     */
    private $_styles=array();
    /**
     * @var ITextWriter writer
     */
    private $_writer=null;

    /**
     * Constructor.
     * @param ITextWriter a writer that THtmlWriter will pass its rendering result to
     */
    public function __construct($writer)
    {
        $this->_writer=$writer;
    }

    public function getWriter()
    {
        return $this->_writer;
    }
    
    public function setWriter($writer)
    {
        $this->_writer = $writer;
    }
    /**
     * Adds a list of attributes to be rendered.
     * @param array list of attributes to be rendered
     */
    public function addAttributes($attrs)
    {
        foreach($attrs as $name=>$value)
            $this->_attributes[$name]=isset(self::$_attrEncode[$name])?THttpUtility::htmlEncode($value):$value;
    }

    /**
     * Adds an attribute to be rendered.
     * @param string name of the attribute
     * @param string value of the attribute
     */
    public function addAttribute($name,$value)
    {
        $this->_attributes[$name]=isset(self::$_attrEncode[$name])?THttpUtility::htmlEncode($value):$value;
    }

    /**
     * Removes the named attribute from rendering
     * @param string name of the attribute to be removed
     */
    public function removeAttribute($name)
    {
        unset($this->_attributes[$name]);
    }

    /**
     * Adds a list of stylesheet attributes to be rendered.
     * @param array list of stylesheet attributes to be rendered
     */
    public function addStyleAttributes($attrs)
    {
        foreach($attrs as $name=>$value)
            $this->_styles[$name]=isset(self::$_styleEncode[$name])?THttpUtility::htmlEncode($value):$value;
    }

    /**
     * Adds a stylesheet attribute to be rendered
     * @param string stylesheet attribute name
     * @param string stylesheet attribute value
     */
    public function addStyleAttribute($name,$value)
    {
        $this->_styles[$name]=isset(self::$_styleEncode[$name])?THttpUtility::htmlEncode($value):$value;
    }

    /**
     * Removes the named stylesheet attribute from rendering
     * @param string name of the stylesheet attribute to be removed
     */
    public function removeStyleAttribute($name)
    {
        unset($this->_styles[$name]);
    }

    /**
     * Flushes the rendering result.
     * This will invoke the underlying writer's flush method.
     */
    public function flush()
    {
        $this->_writer->flush();
    }

    /**
     * Renders a string.
     * @param string string to be rendered
     */
    public function write($str)
    {
        $this->_writer->write($str);
    }

    /**
     * Renders a string and appends a newline to it.
     * @param string string to be rendered
     */
    public function writeLine($str='')
    {
        $this->_writer->write($str."\n");
    }

    /**
     * Renders an HTML break.
     */
    public function writeBreak()
    {
        $this->_writer->write('<br/>');
    }

    /**
     * Renders the openning tag.
     * @param string tag name
     */
    public function renderBeginTag($tagName)
    {
        $str='<'.$tagName;
        foreach($this->_attributes as $name=>$value)
            $str.=' '.$name.'="'.$value.'"';
        if(!empty($this->_styles))
        {
            $str.=' style="';
            foreach($this->_styles as $name=>$value)
                $str.=$name.':'.$value.';';
            $str.='"';
        }
        if(isset(self::$_simpleTags[$tagName]))
        {
            $str.=' />';
            array_push($this->_openTags,'');
        }
        else
        {
            $str.='>';
            array_push($this->_openTags,$tagName);
        }
        $this->_writer->write($str);
        $this->_attributes=array();
        $this->_styles=array();
    }

    /**
     * Renders the closing tag.
     */
    public function renderEndTag()
    {
        if(!empty($this->_openTags) && ($tagName=array_pop($this->_openTags))!=='')
            $this->_writer->write('</'.$tagName.'>');
    }
}

?>