<?php
/**
* Process Extends Visitor
*
* @package Less
* @subpackage visitor
*/
class Less_Visitor_processExtends extends Less_Visitor{
public $allExtendsStack;
/**
* @param Less_Tree_Ruleset $root
*/
public function run( $root ){
$extendFinder = new Less_Visitor_extendFinder();
$extendFinder->run( $root );
if( !$extendFinder->foundExtends){
return $root;
}
$root->allExtends = $this->doExtendChaining( $root->allExtends, $root->allExtends);
$this->allExtendsStack = array();
$this->allExtendsStack[] = &$root->allExtends;
return $this->visitObj( $root );
}
private function doExtendChaining( $extendsList, $extendsListTarget, $iterationCount = 0){
//
// chaining is different from normal extension.. if we extend an extend then we are not just copying, altering and pasting
// the selector we would do normally, but we are also adding an extend with the same target selector
// this means this new extend can then go and alter other extends
//
// this method deals with all the chaining work - without it, extend is flat and doesn't work on other extend selectors
// this is also the most expensive.. and a match on one selector can cause an extension of a selector we had already processed if
// we look at each selector at a time, as is done in visitRuleset
$extendsToAdd = array();
//loop through comparing every extend with every target extend.
// a target extend is the one on the ruleset we are looking at copy/edit/pasting in place
// e.g. .a:extend(.b) {} and .b:extend(.c) {} then the first extend extends the second one
// and the second is the target.
// the separation into two lists allows us to process a subset of chains with a bigger set, as is the
// case when processing media queries
for( $extendIndex = 0, $extendsList_len = count($extendsList); $extendIndex < $extendsList_len; $extendIndex++ ){
for( $targetExtendIndex = 0; $targetExtendIndex < count($extendsListTarget); $targetExtendIndex++ ){
$extend = $extendsList[$extendIndex];
$targetExtend = $extendsListTarget[$targetExtendIndex];
// look for circular references
if( in_array($targetExtend->object_id, $extend->parent_ids,true) ){
continue;
}
// find a match in the target extends self selector (the bit before :extend)
$selectorPath = array( $targetExtend->selfSelectors[0] );
$matches = $this->findMatch( $extend, $selectorPath);
if( $matches ){
// we found a match, so for each self selector..
foreach($extend->selfSelectors as $selfSelector ){
// process the extend as usual
$newSelector = $this->extendSelector( $matches, $selectorPath, $selfSelector);
// but now we create a new extend from it
$newExtend = new Less_Tree_Extend( $targetExtend->selector, $targetExtend->option, 0);
$newExtend->selfSelectors = $newSelector;
// add the extend onto the list of extends for that selector
end($newSelector)->extendList = array($newExtend);
//$newSelector[ count($newSelector)-1]->extendList = array($newExtend);
// record that we need to add it.
$extendsToAdd[] = $newExtend;
$newExtend->ruleset = $targetExtend->ruleset;
//remember its parents for circular references
$newExtend->parent_ids = array_merge($newExtend->parent_ids,$targetExtend->parent_ids,$extend->parent_ids);
// only process the selector once.. if we have :extend(.a,.b) then multiple
// extends will look at the same selector path, so when extending
// we know that any others will be duplicates in terms of what is added to the css
if( $targetExtend->firstExtendOnThisSelectorPath ){
$newExtend->firstExtendOnThisSelectorPath = true;
$targetExtend->ruleset->paths[] = $newSelector;
}
}
}
}
}
if( $extendsToAdd ){
// try to detect circular references to stop a stack overflow.
// may no longer be needed. $this->extendChainCount++;
if( $iterationCount > 100) {
try{
$selectorOne = $extendsToAdd[0]->selfSelectors[0]->toCSS();
$selectorTwo = $extendsToAdd[0]->selector->toCSS();
}catch(Exception $e){
$selectorOne = "{unable to calculate}";
$selectorTwo = "{unable to calculate}";
}
throw new Less_Exception_Parser("extend circular reference detected. One of the circular extends is currently:" . $selectorOne . ":extend(" . $selectorTwo . ")");
}
// now process the new extends on the existing rules so that we can handle a extending b extending c ectending d extending e...
$extendsToAdd = $this->doExtendChaining( $extendsToAdd, $extendsListTarget, $iterationCount+1);
}
return array_merge($extendsList, $extendsToAdd);
}
protected function visitRule( $ruleNode, &$visitDeeper ){
$visitDeeper = false;
}
protected function visitMixinDefinition( $mixinDefinitionNode, &$visitDeeper ){
$visitDeeper = false;
}
protected function visitSelector( $selectorNode, &$visitDeeper ){
$visitDeeper = false;
}
protected function visitRuleset($rulesetNode){
if( $rulesetNode->root ){
return;
}
$allExtends = end($this->allExtendsStack);
$paths_len = count($rulesetNode->paths);
// look at each selector path in the ruleset, find any extend matches and then copy, find and replace
foreach($allExtends as $allExtend){
for($pathIndex = 0; $pathIndex < $paths_len; $pathIndex++ ){
// extending extends happens initially, before the main pass
if( isset($rulesetNode->extendOnEveryPath) && $rulesetNode->extendOnEveryPath ){
continue;
}
$selectorPath = $rulesetNode->paths[$pathIndex];
if( end($selectorPath)->extendList ){
continue;
}
$this->ExtendMatch( $rulesetNode, $allExtend, $selectorPath);
}
}
}
private function ExtendMatch( $rulesetNode, $extend, $selectorPath ){
$matches = $this->findMatch($extend, $selectorPath);
if( $matches ){
foreach($extend->selfSelectors as $selfSelector ){
$rulesetNode->paths[] = $this->extendSelector($matches, $selectorPath, $selfSelector);
}
}
}
private function findMatch($extend, $haystackSelectorPath ){
if( !$this->HasMatches($extend, $haystackSelectorPath) ){
return false;
}
//
// look through the haystack selector path to try and find the needle - extend.selector
// returns an array of selector matches that can then be replaced
//
$needleElements = $extend->selector->elements;
$potentialMatches = array();
$potentialMatches_len = 0;
$potentialMatch = null;
$matches = array();
// loop through the haystack elements
$haystack_path_len = count($haystackSelectorPath);
for($haystackSelectorIndex = 0; $haystackSelectorIndex < $haystack_path_len; $haystackSelectorIndex++ ){
$hackstackSelector = $haystackSelectorPath[$haystackSelectorIndex];
$haystack_elements_len = count($hackstackSelector->elements);
for($hackstackElementIndex = 0; $hackstackElementIndex < $haystack_elements_len; $hackstackElementIndex++ ){
$haystackElement = $hackstackSelector->elements[$hackstackElementIndex];
// if we allow elements before our match we can add a potential match every time. otherwise only at the first element.
if( $extend->allowBefore || ($haystackSelectorIndex === 0 && $hackstackElementIndex === 0) ){
$potentialMatches[] = array('pathIndex'=> $haystackSelectorIndex, 'index'=> $hackstackElementIndex, 'matched'=> 0, 'initialCombinator'=> $haystackElement->combinator);
$potentialMatches_len++;
}
for($i = 0; $i < $potentialMatches_len; $i++ ){
$potentialMatch = &$potentialMatches[$i];
$potentialMatch = $this->PotentialMatch( $potentialMatch, $needleElements, $haystackElement, $hackstackElementIndex );
// if we are still valid and have finished, test whether we have elements after and whether these are allowed
if( $potentialMatch && $potentialMatch['matched'] === $extend->selector->elements_len ){
$potentialMatch['finished'] = true;
if( !$extend->allowAfter && ($hackstackElementIndex+1 < $haystack_elements_len || $haystackSelectorIndex+1 < $haystack_path_len) ){
$potentialMatch = null;
}
}
// if null we remove, if not, we are still valid, so either push as a valid match or continue
if( $potentialMatch ){
if( $potentialMatch['finished'] ){
$potentialMatch['length'] = $extend->selector->elements_len;
$potentialMatch['endPathIndex'] = $haystackSelectorIndex;
$potentialMatch['endPathElementIndex'] = $hackstackElementIndex + 1; // index after end of match
$potentialMatches = array(); // we don't allow matches to overlap, so start matching again
$potentialMatches_len = 0;
$matches[] = $potentialMatch;
}
continue;
}
array_splice($potentialMatches, $i, 1);
$potentialMatches_len--;
$i--;
}
}
}
return $matches;
}
// Before going through all the nested loops, lets check to see if a match is possible
// Reduces Bootstrap 3.1 compile time from ~6.5s to ~5.6s
private function HasMatches($extend, $haystackSelectorPath){
if( !$extend->selector->cacheable ){
return true;
}
$first_el = $extend->selector->_oelements[0];
foreach($haystackSelectorPath as $hackstackSelector){
if( !$hackstackSelector->cacheable ){
return true;
}
if( in_array($first_el, $hackstackSelector->_oelements) ){
return true;
}
}
return false;
}
/**
* @param integer $hackstackElementIndex
*/
private function PotentialMatch( $potentialMatch, $needleElements, $haystackElement, $hackstackElementIndex ){
if( $potentialMatch['matched'] > 0 ){
// selectors add " " onto the first element. When we use & it joins the selectors together, but if we don't
// then each selector in haystackSelectorPath has a space before it added in the toCSS phase. so we need to work out
// what the resulting combinator will be
$targetCombinator = $haystackElement->combinator;
if( $targetCombinator === '' && $hackstackElementIndex === 0 ){
$targetCombinator = ' ';
}
if( $needleElements[ $potentialMatch['matched'] ]->combinator !== $targetCombinator ){
return null;
}
}
// if we don't match, null our match to indicate failure
if( !$this->isElementValuesEqual( $needleElements[$potentialMatch['matched'] ]->value, $haystackElement->value) ){
return null;
}
$potentialMatch['finished'] = false;
$potentialMatch['matched']++;
return $potentialMatch;
}
private function isElementValuesEqual( $elementValue1, $elementValue2 ){
if( $elementValue1 === $elementValue2 ){
return true;
}
if( is_string($elementValue1) || is_string($elementValue2) ) {
return false;
}
if( $elementValue1 instanceof Less_Tree_Attribute ){
return $this->isAttributeValuesEqual( $elementValue1, $elementValue2 );
}
$elementValue1 = $elementValue1->value;
if( $elementValue1 instanceof Less_Tree_Selector ){
return $this->isSelectorValuesEqual( $elementValue1, $elementValue2 );
}
return false;
}
/**
* @param Less_Tree_Selector $elementValue1
*/
private function isSelectorValuesEqual( $elementValue1, $elementValue2 ){
$elementValue2 = $elementValue2->value;
if( !($elementValue2 instanceof Less_Tree_Selector) || $elementValue1->elements_len !== $elementValue2->elements_len ){
return false;
}
for( $i = 0; $i < $elementValue1->elements_len; $i++ ){
if( $elementValue1->elements[$i]->combinator !== $elementValue2->elements[$i]->combinator ){
if( $i !== 0 || ($elementValue1->elements[$i]->combinator || ' ') !== ($elementValue2->elements[$i]->combinator || ' ') ){
return false;
}
}
if( !$this->isElementValuesEqual($elementValue1->elements[$i]->value, $elementValue2->elements[$i]->value) ){
return false;
}
}
return true;
}
/**
* @param Less_Tree_Attribute $elementValue1
*/
private function isAttributeValuesEqual( $elementValue1, $elementValue2 ){
if( $elementValue1->op !== $elementValue2->op || $elementValue1->key !== $elementValue2->key ){
return false;
}
if( !$elementValue1->value || !$elementValue2->value ){
if( $elementValue1->value || $elementValue2->value ) {
return false;
}
return true;
}
$elementValue1 = ($elementValue1->value->value ? $elementValue1->value->value : $elementValue1->value );
$elementValue2 = ($elementValue2->value->value ? $elementValue2->value->value : $elementValue2->value );
return $elementValue1 === $elementValue2;
}
private function extendSelector($matches, $selectorPath, $replacementSelector){
//for a set of matches, replace each match with the replacement selector
$currentSelectorPathIndex = 0;
$currentSelectorPathElementIndex = 0;
$path = array();
$selectorPath_len = count($selectorPath);
for($matchIndex = 0, $matches_len = count($matches); $matchIndex < $matches_len; $matchIndex++ ){
$match = $matches[$matchIndex];
$selector = $selectorPath[ $match['pathIndex'] ];
$firstElement = new Less_Tree_Element(
$match['initialCombinator'],
$replacementSelector->elements[0]->value,
$replacementSelector->elements[0]->index,
$replacementSelector->elements[0]->currentFileInfo
);
if( $match['pathIndex'] > $currentSelectorPathIndex && $currentSelectorPathElementIndex > 0 ){
$last_path = end($path);
$last_path->elements = array_merge( $last_path->elements, array_slice( $selectorPath[$currentSelectorPathIndex]->elements, $currentSelectorPathElementIndex));
$currentSelectorPathElementIndex = 0;
$currentSelectorPathIndex++;
}
$newElements = array_merge(
array_slice($selector->elements, $currentSelectorPathElementIndex, ($match['index'] - $currentSelectorPathElementIndex) ) // last parameter of array_slice is different than the last parameter of javascript's slice
, array($firstElement)
, array_slice($replacementSelector->elements,1)
);
if( $currentSelectorPathIndex === $match['pathIndex'] && $matchIndex > 0 ){
$last_key = count($path)-1;
$path[$last_key]->elements = array_merge($path[$last_key]->elements,$newElements);
}else{
$path = array_merge( $path, array_slice( $selectorPath, $currentSelectorPathIndex, $match['pathIndex'] ));
$path[] = new Less_Tree_Selector( $newElements );
}
$currentSelectorPathIndex = $match['endPathIndex'];
$currentSelectorPathElementIndex = $match['endPathElementIndex'];
if( $currentSelectorPathElementIndex >= count($selectorPath[$currentSelectorPathIndex]->elements) ){
$currentSelectorPathElementIndex = 0;
$currentSelectorPathIndex++;
}
}
if( $currentSelectorPathIndex < $selectorPath_len && $currentSelectorPathElementIndex > 0 ){
$last_path = end($path);
$last_path->elements = array_merge( $last_path->elements, array_slice($selectorPath[$currentSelectorPathIndex]->elements, $currentSelectorPathElementIndex));
$currentSelectorPathIndex++;
}
$slice_len = $selectorPath_len - $currentSelectorPathIndex;
$path = array_merge($path, array_slice($selectorPath, $currentSelectorPathIndex, $slice_len));
return $path;
}
protected function visitMedia( $mediaNode ){
$newAllExtends = array_merge( $mediaNode->allExtends, end($this->allExtendsStack) );
$this->allExtendsStack[] = $this->doExtendChaining($newAllExtends, $mediaNode->allExtends);
}
protected function visitMediaOut(){
array_pop( $this->allExtendsStack );
}
protected function visitDirective( $directiveNode ){
$newAllExtends = array_merge( $directiveNode->allExtends, end($this->allExtendsStack) );
$this->allExtendsStack[] = $this->doExtendChaining($newAllExtends, $directiveNode->allExtends);
}
protected function visitDirectiveOut(){
array_pop($this->allExtendsStack);
}
}