<?php
require_once dirname(__DIR__) . "/parser/parser.php";
require_once dirname(__DIR__) . "/css-parser/css-term.php";
require_once dirname(__DIR__) . "/css-parser/filters/css-attr-filter.php";
require_once dirname(__DIR__) . "/css-parser/filters/css-class-filter.php";
require_once dirname(__DIR__) . "/css-parser/filters/css-id-filter.php";
require_once dirname(__DIR__) . "/css-parser/filters/css-pseudo-first-child-filter.php";
require_once dirname(__DIR__) . "/css-parser/filters/css-pseudo-nth-child-filter.php";
/**
* BNF Grammar:
*
* <expression> ::= <term> {"," <term>}
* <term> ::= <factor> {<factor>}
* <factor> ::= <operator> <element> | <element>
* <element> ::= ("*" | <identifier>) {<filter>}
* <filter> ::= <class-filter> | <id-filter> | <attr->filter> | <pseudo-filter>
* <class-filter> ::= "." <identifier>
* <id-filter> ::= "#" <identifier>
* <attr-filter> ::= "[" <identifier> [<attr-operator> <value>] "]"
* <pseudo-filter> ::= ":" (<pseudo-first-child-filter> | <pseudo-nth-child-filter>)
* <pseudo-nth-child-filter> ::= "nth-child" "(" <number> ")"
* <pseudo-first-child-filter> ::= "first-child"
* <identifier> ::= ( "_" | <alphanum> ) { "_" | "-" | <alphanum> }
* <attr-operator> ::= "=" | "~="
* <operator> ::= ">" | "+"
* <value> ::= <quoted string> | <alphanum> {<alphanum>}
*/
class CSSParser extends Parser {
/**
* Identifier pattern.
*/
const IDENTIFIER = "[_a-z0-9][_\-a-z0-9]*";
/**
* List of operators.
* @var array of strings
*/
private $operators = array(">", "+");
/**
* List of 'attribute operators'.
* @var array of strings
*/
private $attr_operators = array("=", "~=");
/**
* A node context.
* @var DOMNode
*/
private $node;
/**
* @param DOMNode $node
* @param string $query CSS selector expression
*/
public function __construct($node, $query) {
$this->node = $node;
parent::__construct($query);
}
/**
* Is the node in array?
* @param DOMNode $node
* @param array(DOMNode, ...) $items
* @return boolean
*/
private function isNodeInArray($node, $items) {
foreach ($items as $item) {
if ($node->isSameNode($item)) {
return TRUE;
}
}
return FALSE;
}
/**
* Is the next an operator?
* <operator> ::= ">" | "+"
*
* @return FALSE|array(string)
*/
protected function operator() {
return $this->in($this->operators);
}
/**
* Is the next an attribute operator?
* <attr-operator> ::= "=" | "~="
*
* @return FALSE|array(string)
*/
protected function attrOperator() {
return $this->in(CSSAttrFilter::getOperators());
}
/**
* Is the next an identifier?
* <identifier> ::= ( "_" | <alphanum> ) { "_" | "-" | <alphanum> }
*
* @return FALSE|array(string)
*/
protected function identifier() {
if (list($id) = $this->match(CSSparser::IDENTIFIER)) {
return array($id);
}
return FALSE;
}
/**
* Is the next a value?
* <value> ::= <a quoted string> | <a list of alphanumeric characters>
*
* The following examples are values:
* 'hello'
* "hello\"man"
* 'hello\'man'
* 0015blah
* _blah_
*
* @return FALSE|array(string)
*/
protected function value() {
if ( !(list($value) = $this->str()) && !(list($value) = $this->match(CSSParser::IDENTIFIER)) ) {
return array($value);
}
return array($value);
}
/**
* Is the next a nth-child pseudo filter?
* <pseudo-nth-child-filter> ::= "nth-child" "(" <number> ")"
*
* @return FALSE|CSSPseudoNthChildFilter
*/
protected function pseudoNthChildFilter() {
$position = 0;
if (!$this->eq("nth-child")) {
return FALSE;
}
if (!$this->eq("(")) {
throw new ParserException($this, "Invalid expression");
}
if (!list($position) = $this->number()) {
throw new ParserException($this, "Invalid position");
}
if (!$this->eq(")")) {
throw new ParserException($this, "Invalid expression");
}
return new CSSPseudoNthChildFilter(intval($position));
}
/**
* Is the next a first-child pseudo filter?
* <pseudo-first-child-filter> ::= "first-child"
*
* @return FALSE|CSSPseudoFirstChildFilter
*/
protected function pseudoFirstChildFilter() {
if (!$this->eq("first-child")) {
return FALSE;
}
return new CSSPseudoFirstChildFilter();
}
/**
* Is the next a speudo filter?
* <pseudo-filter> ::= ":" (<pseudo-first-child-filter> | <pseudo-nth-child-filter>)
*
* @return FALSE|CSSPseudoFilter
*/
protected function pseudoFilter() {
$filter = NULL;
if (!$this->match("/^\:/")) {
return FALSE;
}
if (
(!$filter = $this->is("pseudoFirstChildFilter")) &&
(!$filter = $this->is("pseudoNthChildFilter"))
) {
throw new ParserException($this, "Invalid pseudo filter");
}
return $filter;
}
/**
* Is the next an attribute filter?
* <attr-filter> ::= "[" <identifier> (<attr-operator> <value>) "]"
*
* @return FALSE|CSSAttrFilter
*/
protected function attrFilter() {
$attr_name = "";
$op = "";
$value = "";
if (!$this->match("/^\[/")) {
return FALSE;
}
if (!list($attr_name) = $this->is("identifier")) {
throw new ParserException($this, "Invalid identifier");
}
if (list($op) = $this->is("attrOperator")) {
if (!list($value) = $this->is("value")) {
throw new ParserException($this, "Invalid attribute operator");
}
}
if (!$this->eq("]")) {
throw new ParserException($this, "Invalid expression");
}
return new CSSAttrFilter($attr_name, $op, $value);
}
/**
* Is the next an id filter?
* <id-filter> ::= "#" <identifier>
*
* @return FALSE|CSSIdFilter
*/
protected function idFilter() {
$id = "";
if (!$this->match("/^\#/")) {
return FALSE;
}
if (!list($id) = $this->is("identifier")) {
throw new ParserException($this, "Invalid identifier");
}
return new CSSIdFilter($id);
}
/**
* Is the next a class filter?
* <class-filter> ::= "." <identifier>
*
* @return FALSE|CSSClassFilter
*/
protected function classFilter() {
$class_name = "";
if (!$this->match("/^\./")) {
return FALSE;
}
if (!list($class_name) = $this->is("identifier")) {
throw new ParserException($this, "Invalid identifier");
}
return new CSSClassFilter($class_name);
}
/**
* Is the next a filter?
* <filter> ::= <class-filter> | <id-filter> | <attr->filter> | <pseudo-filter>
*
* @return FALSE|CSSFilter
*/
protected function filter() {
$filter = NULL;
if (
(!$filter = $this->is("classFilter")) &&
(!$filter = $this->is("idFilter")) &&
(!$filter = $this->is("attrFilter")) &&
(!$filter = $this->is("pseudoFilter"))
) {
return FALSE;
}
return $filter;
}
/**
* Is the next an element?
* <element> ::= ("*" | <identifier> | <filter>) {<filter>}
*
* The following example is an element:
* div.my-class[title = hello]:nth-child(1)
*
* In the above example, 'div' is the tag name and the following strings are filters:
* .my-class // a class filter
* [title = hello] // an attribute filter
* :nth-child(1) // a pseudo filter
*
* @return FALSE|CSSElement
*/
protected function element() {
$element = NULL;
$filter = NULL;
$tag_name = "*";
// ignores left spaces
$this->match("\s+");
if ( (list($name) = $this->eq("*")) || (list($name) = $this->is("identifier")) ) {;
$tag_name = $name? $name : "*";
} else
if (!$filter = $this->is("filter")) {
return FALSE;
}
$element = new CSSElement($tag_name);
// first filter
if ($filter) {
$element->addFilter($filter);
}
// additional filters
while ($filter = $this->is("filter")) {
$element->addFilter($filter);
}
return $element;
}
/**
* Is the next a factor?
* <factor> ::= <operator> <element> | <element>
*
* The following example is a factor:
* > div.my-class[title = hello]
*
* In the above example, ">" is an operator and "div.my-class[title = hello]" is an element.
*
* @return FALSE|CSSFactor
*/
protected function factor() {
$op = "";
if (list($op) = $this->is("operator")) {
if (!$element = $this->is("element")) {
throw new ParserException($this, "Invalid expression");
}
} else
if (!$element = $this->is("element")) {
return FALSE;
}
return new CSSFactor($op, $element);
}
/**
* Is the next a term?
* <term> ::= <factor> {<factor>}
*
* The following example is a term:
* div > div.class h2[title = 'main-title'] + h3
*
* In the above example, the following strings are factors:
* div
* > div.class
* h2[title = 'main-title']
* + h3
*
* @return FALSE|CSSTerm
*/
protected function term() {
$factor = NULL;
// first factor
if (!$factor = $this->is("factor")) {
return FALSE;
}
$term = new CSSTerm();
$term->addFactor($factor);
// additional factors
while ($factor = $this->is("factor")) {
$term->addFactor($factor);
}
return $term;
}
/**
* Is the next a css selector expression?
* <expression> ::= <term> {"," <term>}
*
* The following example is an expression:
* div > div.class div#id, div > p, pre
*
* In the above example, the following strings are terms:
* div > div.class div
* div > p
* pre
*
* @return array(DOMElement, ...)
*/
protected function expression() {
$nodes = array();
do {
if (!$term = $this->is("term")) {
throw new ParserException($this, "Invalid expression");
}
$nodes = CSSHelper::mergeNodes($nodes, $term->filter($this->node));
} while ($this->eq(","));
return $nodes;
}
protected function _parse() {
return $this->is("expression");
}
}
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