FillSlot.php
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<?php
/**
* PHPTAL templating engine
*
* PHP Version 5
*
* @category HTML
* @package PHPTAL
* @author Laurent Bedubourg <lbedubourg@motion-twin.com>
* @author Kornel Lesiński <kornel@aardvarkmedia.co.uk>
* @license http://www.gnu.org/licenses/lgpl.html GNU Lesser General Public License
* @version SVN: $Id: FillSlot.php 710 2009-09-07 11:46:50Z kornel $
* @link http://phptal.org/
*/
/**
* METAL Specification 1.0
*
* argument ::= Name
*
* Example:
*
* <table metal:use-macro="here/doc1/macros/sidebar">
* <tr><th>Links</th></tr>
* <tr><td metal:fill-slot="links">
* <a href="http://www.goodplace.com">Good Place</a><br>
* <a href="http://www.badplace.com">Bad Place</a><br>
* <a href="http://www.otherplace.com">Other Place</a>
* </td></tr>
* </table>
*
* PHPTAL:
*
* 1. evaluate slots
*
* <?php ob_start(); ? >
* <td>
* <a href="http://www.goodplace.com">Good Place</a><br>
* <a href="http://www.badplace.com">Bad Place</a><br>
* <a href="http://www.otherplace.com">Other Place</a>
* </td>
* <?php $tpl->slots->links = ob_get_contents(); ob_end_clean(); ? >
*
* 2. call the macro (here not supported)
*
* <?php echo phptal_macro($tpl, 'master_page.html/macros/sidebar'); ? >
*
*
* @package PHPTAL
* @subpackage Php.attribute.metal
* @author Laurent Bedubourg <lbedubourg@motion-twin.com>
*/
class PHPTAL_Php_Attribute_METAL_FillSlot extends PHPTAL_Php_Attribute
{
private static $uid = 0;
private $function_name;
public function before(PHPTAL_Php_CodeWriter $codewriter)
{
if ($this->shouldUseCallback()) {
$function_base_name = 'slot_'.preg_replace('/[^a-z0-9]/','_',$this->expression).'_'.(self::$uid++);
$codewriter->doFunction($function_base_name,'PHPTAL $_thistpl, PHPTAL $tpl');
$this->function_name = $codewriter->getFunctionPrefix().$function_base_name;
$codewriter->doSetVar('$ctx','$tpl->getContext()');
$codewriter->doSetVar('$_translator', '$tpl->getTranslator()');
} else {
$codewriter->pushCode('ob_start()');
$this->function_name = NULL;
}
}
public function after(PHPTAL_Php_CodeWriter $codewriter)
{
if ($this->function_name !== NULL) {
$codewriter->doEnd();
$codewriter->pushCode('$ctx->fillSlotCallback('.$codewriter->str($this->expression).', '.$codewriter->str($this->function_name).', $_thistpl, clone $tpl)');
} else {
$codewriter->pushCode('$ctx->fillSlot('.$codewriter->str($this->expression).', ob_get_clean())');
}
}
// rough guess
const CALLBACK_THRESHOLD = 10000;
/**
* inspects contents of the element to decide whether callback makes sense
*/
private function shouldUseCallback()
{
// since callback is slightly slower than buffering,
// use callback only for content that is large to offset speed loss by memory savings
return $this->estimateNumberOfBytesOutput($this->phpelement, false) > self::CALLBACK_THRESHOLD;
}
/**
* @param bool $is_nested_in_repeat true if any parent element has tal:repeat
* @return rough guess
*/
private function estimateNumberOfBytesOutput(PHPTAL_Dom_Element $element, $is_nested_in_repeat)
{
// macros don't output anything on their own
if ($element->hasAttributeNS('http://xml.zope.org/namespaces/metal','define-macro')) {
return 0;
}
$estimated_bytes = 2*(3+strlen($element->getQualifiedName()));
foreach($element->getAttributeNodes() as $attr) {
$estimated_bytes += 4+strlen($attr->getQualifiedName());
$estimated_bytes += strlen($attr->getValueEscaped()); // this is shoddy for replaced attributes
}
$has_repeat_attr = $element->hasAttributeNS('http://xml.zope.org/namespaces/tal','repeat');
if ($element->hasAttributeNS('http://xml.zope.org/namespaces/tal','content') ||
$element->hasAttributeNS('http://xml.zope.org/namespaces/tal','replace')) {
// assume that output in loops is shorter (e.g. table rows) than outside (main content)
$estimated_bytes += ($has_repeat_attr || $is_nested_in_repeat) ? 500 : 2000;
} else {
foreach($element->childNodes as $node) {
if ($node instanceof PHPTAL_Dom_Element) {
$estimated_bytes += $this->estimateNumberOfBytesOutput($node, $has_repeat_attr || $is_nested_in_repeat);
} else {
$estimated_bytes += strlen($node->getValueEscaped());
}
}
}
if ($element->hasAttributeNS('http://xml.zope.org/namespaces/metal','use-macro')) {
$estimated_bytes += ($has_repeat_attr || $is_nested_in_repeat) ? 500 : 2000;
}
if ($element->hasAttributeNS('http://xml.zope.org/namespaces/tal','condition')) {
$estimated_bytes /= 2; // naively assuming 50% chance, that works well with if/else pattern
}
if ($element->hasAttributeNS('http://xml.zope.org/namespaces/tal','repeat')) {
// assume people don't write big nested loops
$estimated_bytes *= $is_nested_in_repeat ? 5 : 10;
}
return $estimated_bytes;
}
}