s9e\TextFormatter\Configurator\Helpers\TemplateParser\Normalizer

Complexity

Total Complexity

43

Size/Duplication

Total Lines	331
Duplicated Lines	0 %

Coupling/Cohesion

Components	1
Dependencies	3

Importance

Changes	1
Bugs	0	Features	0

12 Methods

Rating	Name	Duplication	Size	Complexity
A	__construct()	0	4	1
A	normalize()	0	12	1
B	addCloseTagElements()	0	26	4
A	addDefaultCase()	0	7	2
A	addElementIds()	0	8	2
A	getOutputContext()	0	17	3
A	getParentElementId()	0	12	3
C	isEmpty()	0	42	7
C	markBranchTables()	0	48	9
A	markConditionalCloseTagElements()	0	23	3
B	markEmptyElements()	0	25	6
A	setOutputContext()	0	7	2

<?php

/**
* @package   s9e\TextFormatter
* @copyright Copyright (c) 2010-2018 The s9e Authors
* @license   http://www.opensource.org/licenses/mit-license.php The MIT License
*/
namespace s9e\TextFormatter\Configurator\Helpers\TemplateParser;

use DOMDocument;
use DOMElement;
use DOMNode;
use s9e\TextFormatter\Configurator\Helpers\XPathHelper;

class Normalizer extends IRProcessor
{
	/**
	* @var Optimizer
	*/
	protected $optimizer;

	/**
	* @var string Regexp that matches the names of all void elements
	* @link http://www.w3.org/TR/html-markup/syntax.html#void-elements
	*/
	public $voidRegexp = '/^(?:area|base|br|col|command|embed|hr|img|input|keygen|link|meta|param|source|track|wbr)$/Di';

	/**
	* @param  Optimizer $optimizer
	* @return void
	*/
	public function __construct(Optimizer $optimizer)
	{
		$this->optimizer = $optimizer;
	}

	/**
	* Normalize an IR
	*
	* @param  DOMDocument $ir
	* @return void
	*/
	public function normalize(DOMDocument $ir)
	{
		$this->createXPath($ir);
		$this->addDefaultCase($ir);
		$this->addElementIds($ir);
		$this->addCloseTagElements($ir);
		$this->markEmptyElements($ir);
		$this->optimizer->optimize($ir);
		$this->markConditionalCloseTagElements($ir);
		$this->setOutputContext($ir);
		$this->markBranchTables($ir);
	}

	/**
	* Add <closeTag/> elements everywhere an open start tag should be closed
	*
	* @param  DOMDocument $ir
	* @return void
	*/
	protected function addCloseTagElements(DOMDocument $ir)
	{
		$exprs = [
			'//applyTemplates[not(ancestor::attribute)]',
			'//comment',
			'//element',
			'//output[not(ancestor::attribute)]'
		];
		foreach ($this->query(implode('|', $exprs)) as $node)
		{
			$parentElementId = $this->getParentElementId($node);
			if (isset($parentElementId))
			{
				$node->parentNode
				     ->insertBefore($ir->createElement('closeTag'), $node)
				     ->setAttribute('id', $parentElementId);
			}

			// Append a <closeTag/> to <element/> nodes to ensure that empty elements get closed
			if ($node->nodeName === 'element')
			{
				$id = $node->getAttribute('id');
				$this->appendElement($node, 'closeTag')->setAttribute('id', $id);
			}
		}
	}

	/**
	* Add an empty default <case/> to <switch/> nodes that don't have one
	*
	* @param  DOMDocument $ir
	* @return void
	*/
	protected function addDefaultCase(DOMDocument $ir)
	{
		foreach ($this->query('//switch[not(case[not(@test)])]') as $switch)
		{
			$this->appendElement($switch, 'case');
		}
	}

	/**
	* Add an id attribute to <element/> nodes
	*
	* @param  DOMDocument $ir
	* @return void
	*/
	protected function addElementIds(DOMDocument $ir)
	{
		$id = 0;
		foreach ($ir->getElementsByTagName('element') as $element)
		{
			$element->setAttribute('id', ++$id);
		}
	}

	/**
	* Get the context type for given output element
	*
	* @param  DOMNode $output
	* @return string
	*/
	protected function getOutputContext(DOMNode $output)
	{
		$contexts = [
			'boolean(ancestor::attribute)'             => 'attribute',
			'@disable-output-escaping="yes"'           => 'raw',
			'count(ancestor::element[@name="script"])' => 'raw'
		];
		foreach ($contexts as $expr => $context)
		{
			if ($this->evaluate($expr, $output))
			{
				return $context;
			}
		}

		return 'text';
	}

	/**
	* Get the ID of the closest "element" ancestor
	*
	* @param  DOMNode     $node Context node
	* @return string|null
	*/
	protected function getParentElementId(DOMNode $node)
	{
		$parentNode = $node->parentNode;
		while (isset($parentNode))
		{
			if ($parentNode->nodeName === 'element')
			{
				return $parentNode->getAttribute('id');
			}
			$parentNode = $parentNode->parentNode;
		}
	}

	/**
	* Test whether given element will be empty at runtime (no content, no children)
	*
	* @param  DOMElement $ir Element in the IR
	* @return string         'yes', 'maybe' or 'no'
	*/
	protected function isEmpty(DOMElement $ir)
	{
		// Comments and elements count as not-empty and literal output is sure to output something
		if ($this->evaluate('count(comment | element | output[@type="literal"])', $ir))
		{
			return 'no';
		}

		// Test all branches of a <switch/>
		// NOTE: this assumes that <switch/> are normalized to always have a default <case/>
		$cases = [];
		foreach ($this->query('switch/case', $ir) as $case)
		{
			$cases[$this->isEmpty($case)] = 1;
		}

		if (isset($cases['maybe']))
		{
			return 'maybe';
		}

		if (isset($cases['no']))
		{
			// If all the cases are not-empty, the element is not-empty
			if (!isset($cases['yes']))
			{
				return 'no';
			}

			// Some 'yes' and some 'no', the element is a 'maybe'
			return 'maybe';
		}

		// Test for <apply-templates/> or XPath output
		if ($this->evaluate('count(applyTemplates | output[@type="xpath"])', $ir))
		{
			// We can't know in advance whether those will produce output
			return 'maybe';
		}

		return 'yes';
	}

	/**
	* Mark switch elements that are used as branch tables
	*
	* If a switch is used for a series of equality tests against the same attribute or variable, the
	* attribute/variable is stored within the switch as "branch-key" and the values it is compared
	* against are stored JSON-encoded in the case as "branch-values". It can be used to create
	* optimized branch tables
	*
	* @param  DOMDocument $ir
	* @return void
	*/
	protected function markBranchTables(DOMDocument $ir)
	{

		// Iterate over switch elements that have at least two case children with a test attribute
		foreach ($this->query('//switch[case[2][@test]]') as $switch)
		{
			$key = null;
			$branchValues = [];

			foreach ($switch->childNodes as $i => $case)
			{
				if (!$case->hasAttribute('test'))
				{
					continue;
				}

				$map = XPathHelper::parseEqualityExpr($case->getAttribute('test'));

				// Test whether the expression matches an equality
				if ($map === false)
				{
					continue 2;
				}

				// Abort if there's more than 1 variable used
				if (count($map) !== 1)
				{
					continue 2;
				}

				// Test whether it uses the same key
				if (isset($key) && $key !== key($map))
				{
					continue 2;
				}

				$key = key($map);
				$branchValues[$i] = end($map);
			}

			$switch->setAttribute('branch-key', $key);
			foreach ($branchValues as $i => $values)
			{
				sort($values);
				$switch->childNodes->item($i)->setAttribute('branch-values', serialize($values));
			}
		}
	}

	/**
	* Mark conditional <closeTag/> nodes
	*
	* @param  DOMDocument $ir
	* @return void
	*/
	protected function markConditionalCloseTagElements(DOMDocument $ir)
	{
		foreach ($ir->getElementsByTagName('closeTag') as $closeTag)
		{
			$id = $closeTag->getAttribute('id');

			// For each <switch/> ancestor, look for a <closeTag/> and that is either a sibling or
			// the descendant of a sibling, and that matches the id
			$query = 'ancestor::switch/'
			       . 'following-sibling::*/'
			       . 'descendant-or-self::closeTag[@id = "' . $id . '"]';
			foreach ($this->query($query, $closeTag) as $following)
			{
				// Mark following <closeTag/> nodes to indicate that the status of this tag must
				// be checked before it is closed
				$following->setAttribute('check', '');

				// Mark the current <closeTag/> to indicate that it must set a flag to indicate
				// that its tag has been closed
				$closeTag->setAttribute('set', '');
			}
		}
	}

	/**
	* Mark void elements and elements with no content
	*
	* @param  DOMDocument $ir
	* @return void
	*/
	protected function markEmptyElements(DOMDocument $ir)
	{
		foreach ($ir->getElementsByTagName('element') as $element)
		{
			// Test whether this element is (maybe) void
			$elName = $element->getAttribute('name');
			if (strpos($elName, '{') !== false)
			{
				// Dynamic element names must be checked at runtime
				$element->setAttribute('void', 'maybe');
			}
			elseif (preg_match($this->voidRegexp, $elName))
			{
				// Static element names can be checked right now
				$element->setAttribute('void', 'yes');
			}

			// Find whether this element is empty
			$isEmpty = $this->isEmpty($element);
			if ($isEmpty === 'yes' || $isEmpty === 'maybe')
			{
				$element->setAttribute('empty', $isEmpty);
			}
		}
	}

	/**
	* Fill in output context
	*
	* @param  DOMDocument $ir
	* @return void
	*/
	protected function setOutputContext(DOMDocument $ir)
	{
		foreach ($ir->getElementsByTagName('output') as $output)
		{
			$output->setAttribute('escape', $this->getOutputContext($output));
		}
	}
}