s9e\TextFormatter\Configurator\TemplateNormalizations\OptimizeChoose

Complexity

Total Complexity

48

Size/Duplication

Total Lines	353
Duplicated Lines	0 %

Coupling/Cohesion

Components	1
Dependencies	1

Importance

Changes

0

20 Methods

Rating	Name	Duplication	Size	Complexity
A	getAttributes()	0	11	2
A	getBranches()	0	6	1
A	hasNoContent()	0	6	1
A	hasOtherwise()	0	4	1
A	isEqualNode()	0	4	1
A	isEqualTag()	0	4	3
A	normalize()	0	9	2
A	adoptChildren()	0	8	2
A	isXslChoose()	0	4	2
B	matchBranches()	0	19	5
C	matchOnlyChild()	0	29	7
A	moveFirstChildBefore()	0	9	2
A	moveLastChildAfter()	0	17	3
A	optimizeChooseElement()	0	18	3
A	optimizeCommonFirstChild()	0	7	2
A	optimizeCommonLastChild()	0	7	2
A	optimizeCommonOnlyChild()	0	7	2
A	optimizeEmptyOtherwise()	0	8	2
A	optimizeSingleBranch()	0	17	3
A	reparentChild()	0	11	2

<?php

/**
* @package   s9e\TextFormatter
* @copyright Copyright (c) 2010-2017 The s9e Authors
* @license   http://www.opensource.org/licenses/mit-license.php The MIT License
*/
namespace s9e\TextFormatter\Configurator\TemplateNormalizations;

use DOMElement;
use DOMNode;
use DOMXPath;
use s9e\TextFormatter\Configurator\TemplateNormalization;

class OptimizeChoose extends TemplateNormalization
{
	/**
	* @var DOMElement Current xsl:choose element
	*/
	protected $choose;

	/**
	* @var DOMXPath XPath object for current template
	*/
	protected $xpath;

	/**
	* Optimize xsl:choose branches by moving their common children out of them
	*
	* @param  DOMElement $template <xsl:template/> node
	* @return void
	*/
	public function normalize(DOMElement $template)
	{
		$this->xpath = new DOMXPath($template->ownerDocument);
		foreach ($template->getElementsByTagNameNS(self::XMLNS_XSL, 'choose') as $choose)
		{
			$this->choose = $choose;
			$this->optimizeChooseElement();
		}
	}

	/**
	* Adopt the children of given element's only child
	*
	* @param  DOMElement $branch
	* @return void
	*/
	protected function adoptChildren(DOMElement $branch)
	{
		while ($branch->firstChild->firstChild)
		{
			$branch->appendChild($branch->firstChild->removeChild($branch->firstChild->firstChild));
		}
		$branch->removeChild($branch->firstChild);
	}

	/**
	* Retrieve a list of attributes from given element
	*
	* @return array NamespaceURI#nodeName as keys, attribute values as values
	*/
	protected function getAttributes(DOMElement $element)
	{
		$attributes = array();
		foreach ($element->attributes as $attribute)
		{
			$key = $attribute->namespaceURI . '#' . $attribute->nodeName;
			$attributes[$key] = $attribute->nodeValue;
		}

		return $attributes;
	}

	/**
	* Return a list the xsl:when and xsl:otherwise children of current xsl:choose element
	*
	* @return DOMElement[]
	*/
	protected function getBranches()
	{
		$query = 'xsl:when|xsl:otherwise';

		return iterator_to_array($this->xpath->query($query, $this->choose));
	}

	/**
	* Test whether current xsl:choose element has no content besides xsl:when and xsl:otherwise
	*
	* @return bool
	*/
	protected function hasNoContent()
	{
		$query = 'count(xsl:when/node() | xsl:otherwise/node())';

		return !$this->xpath->evaluate($query, $this->choose);
	}

	/**
	* Test whether current xsl:choose element has an xsl:otherwise child
	*
	* @return bool
	*/
	protected function hasOtherwise()
	{
		return (bool) $this->xpath->evaluate('count(xsl:otherwise)', $this->choose);
	}

	/**
	* Test whether two nodes are identical
	*
	* ext/dom does not support isEqualNode() from DOM Level 3 so this is a makeshift replacement.
	* Unlike the DOM 3 function, attributes order matters
	*
	* @param  DOMNode $node1
	* @param  DOMNode $node2
	* @return bool
	*/
	protected function isEqualNode(DOMNode $node1, DOMNode $node2)
	{
		return ($node1->ownerDocument->saveXML($node1) === $node2->ownerDocument->saveXML($node2));
	}

	/**
	* Test whether two elements have the same start tag
	*
	* @param  DOMElement $el1
	* @param  DOMElement $el2
	* @return bool
	*/
	protected function isEqualTag(DOMElement $el1, DOMElement $el2)
	{
		return ($el1->namespaceURI === $el2->namespaceURI && $el1->nodeName === $el2->nodeName && $this->getAttributes($el1) === $this->getAttributes($el2));
	}

	/**
	* Test whether given node is an xsl:choose element
	*
	* @param  DOMNode $node
	* @return bool
	*/
	protected function isXslChoose(DOMNode $node)
	{
		return ($node->namespaceURI === self::XMLNS_XSL && $node->localName === 'choose');
	}

	/**
	* Test whether all branches of current xsl:choose element share a common firstChild/lastChild
	*
	* @param  string $childType Either firstChild or lastChild
	* @return bool
	*/
	protected function matchBranches($childType)
	{
		$branches = $this->getBranches();
		if (!isset($branches[0]->$childType))
		{
			return false;
		}

		$childNode = $branches[0]->$childType;
		foreach ($branches as $branch)
		{
			if (!isset($branch->$childType) || !$this->isEqualNode($childNode, $branch->$childType))
			{
				return false;
			}
		}

		return true;
	}

	/**
	* Test whether all branches of current xsl:choose element have a single child with the same start tag
	*
	* @return bool
	*/
	protected function matchOnlyChild()
	{
		$branches = $this->getBranches();
		if (!isset($branches[0]->firstChild))
		{
			return false;
		}

		$firstChild = $branches[0]->firstChild;
		if ($this->isXslChoose($firstChild))
		{
			// Abort on xsl:choose because we can't move it without moving its children
			return false;
		}

		foreach ($branches as $branch)
		{
			if ($branch->childNodes->length !== 1 || !($branch->firstChild instanceof DOMElement))
			{
				return false;
			}
			if (!$this->isEqualTag($firstChild, $branch->firstChild))
			{
				return false;
			}
		}

		return true;
	}

	/**
	* Move the firstChild of each branch before current xsl:choose
	*
	* @return void
	*/
	protected function moveFirstChildBefore()
	{
		$branches = $this->getBranches();
		$this->choose->parentNode->insertBefore(array_pop($branches)->firstChild, $this->choose);
		foreach ($branches as $branch)
		{
			$branch->removeChild($branch->firstChild);
		}
	}

	/**
	* Move the lastChild of each branch after current xsl:choose
	*
	* @return void
	*/
	protected function moveLastChildAfter()
	{
		$branches = $this->getBranches();
		$node     = array_pop($branches)->lastChild;
		if (isset($this->choose->nextSibling))
		{
			$this->choose->parentNode->insertBefore($node, $this->choose->nextSibling);
		}
		else
		{
			$this->choose->parentNode->appendChild($node);
		}
		foreach ($branches as $branch)
		{
			$branch->removeChild($branch->lastChild);
		}
	}

	/**
	* Optimize current xsl:choose element
	*
	* @return void
	*/
	protected function optimizeChooseElement()
	{
		if ($this->hasOtherwise())
		{
			$this->optimizeCommonFirstChild();
			$this->optimizeCommonLastChild();
			$this->optimizeCommonOnlyChild();
			$this->optimizeEmptyOtherwise();
		}
		if ($this->hasNoContent())
		{
			$this->choose->parentNode->removeChild($this->choose);
		}
		else
		{
			$this->optimizeSingleBranch();
		}
	}

	/**
	* Optimize current xsl:choose by moving out the first child of each branch if they match
	*
	* @return void
	*/
	protected function optimizeCommonFirstChild()
	{
		while ($this->matchBranches('firstChild'))
		{
			$this->moveFirstChildBefore();
		}
	}

	/**
	* Optimize current xsl:choose by moving out the last child of each branch if they match
	*
	* @return void
	*/
	protected function optimizeCommonLastChild()
	{
		while ($this->matchBranches('lastChild'))
		{
			$this->moveLastChildAfter();
		}
	}

	/**
	* Optimize current xsl:choose by moving out only child of each branch if they match
	*
	* This will reorder xsl:choose/xsl:when/div into div/xsl:choose/xsl:when if every branch has
	* the same only child (excluding the child's own descendants)
	*
	* @return void
	*/
	protected function optimizeCommonOnlyChild()
	{
		while ($this->matchOnlyChild())
		{
			$this->reparentChild();
		}
	}

	/**
	* Optimize away the xsl:otherwise child of current xsl:choose if it's empty
	*
	* @return void
	*/
	protected function optimizeEmptyOtherwise()
	{
		$query = 'xsl:otherwise[count(node()) = 0]';
		foreach ($this->xpath->query($query, $this->choose) as $otherwise)
		{
			$this->choose->removeChild($otherwise);
		}
	}

	/**
	* Replace current xsl:choose with xsl:if if it has only one branch
	*
	* @return void
	*/
	protected function optimizeSingleBranch()
	{
		$query = 'count(xsl:when) = 1 and not(xsl:otherwise)';
		if (!$this->xpath->evaluate($query, $this->choose))
		{
			return;
		}
		$when = $this->xpath->query('xsl:when', $this->choose)->item(0);
		$if   = $this->choose->ownerDocument->createElementNS(self::XMLNS_XSL, 'xsl:if');
		$if->setAttribute('test', $when->getAttribute('test'));
		while ($when->firstChild)
		{
			$if->appendChild($when->removeChild($when->firstChild));
		}

		$this->choose->parentNode->replaceChild($if, $this->choose);
	}

	/**
	* Reorder the current xsl:choose tree to make it a child of the first child of its first branch
	*
	* This will reorder xsl:choose/xsl:when/div into div/xsl:choose/xsl:when
	*
	* @return void
	*/
	protected function reparentChild()
	{
		$branches  = $this->getBranches();
		$childNode = $branches[0]->firstChild->cloneNode();
		$childNode->appendChild($this->choose->parentNode->replaceChild($childNode, $this->choose));

		foreach ($branches as $branch)
		{
			$this->adoptChildren($branch);
		}
	}
}