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<?php
/**
* @package s9e\TextFormatter
* @copyright Copyright (c) 2010-2022 The s9e authors
* @license http://www.opensource.org/licenses/mit-license.php The MIT License
*/
namespace s9e\TextFormatter\Configurator\TemplateNormalizations;
use DOMElement;
class OptimizeChoose extends AbstractChooseOptimization
{
/**
* 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);
}
/**
* 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->isXsl($firstChild, 'choose'))
{
// Abort on xsl:choose because we can't move it without moving its children
return false;
}
foreach ($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);
}
}
/**
* {@inheritdoc}
*/
protected function optimizeChoose()
{
if ($this->hasOtherwise())
{
$this->optimizeCommonFirstChild();
$this->optimizeCommonLastChild();
$this->optimizeCommonOnlyChild();
$this->optimizeEmptyBranch();
$this->optimizeEmptyOtherwise();
}
if ($this->isEmpty())
{
$this->choose->parentNode->removeChild($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();
}
}
/**
* Switch the logic of an xsl:otherwise if the only other branch is empty
*
* @return void
*/
protected function optimizeEmptyBranch()
{
$query = 'count(xsl:when) = 1 and count(xsl:when/node()) = 0 and xsl:otherwise';
if (!$this->xpath->evaluate($query, $this->choose))
{
return;
}
// test="@foo" becomes test="not(@foo)"
$when = $this->xpath('xsl:when', $this->choose)[0];
$when->setAttribute('test', 'not(' . $when->getAttribute('test') . ')');
$otherwise = $this->xpath('xsl:otherwise', $this->choose)[0];
while ($otherwise->firstChild)
{
$when->appendChild($otherwise->removeChild($otherwise->firstChild));
}
}
/**
* 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, $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('xsl:when', $this->choose)[0];
$if = $this->createElement('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);
}
}
}