From f38f27cec58ca39ae74179c29a59ed690e2125b3 Mon Sep 17 00:00:00 2001
From: Ivo Petkov <ivo@ivopetkov.com>
Date: Fri, 8 Dec 2017 09:03:50 +0200
Subject: [PATCH] Performance optimizations.

---
 .../Internal/QuerySelectors.php               | 67 +++++++++++--------
 1 file changed, 40 insertions(+), 27 deletions(-)

diff --git a/src/HTML5DOMDocument/Internal/QuerySelectors.php b/src/HTML5DOMDocument/Internal/QuerySelectors.php
index 87c633a..daa6fe9 100644
--- a/src/HTML5DOMDocument/Internal/QuerySelectors.php
+++ b/src/HTML5DOMDocument/Internal/QuerySelectors.php
@@ -7,7 +7,7 @@ trait QuerySelectors
 
     /**
      * Returns the first element matching the selector
-     *
+     * 
      * @param string $selector CSS query selector
      * @return \DOMElement|null The result DOMElement or null if not found
      */
@@ -19,33 +19,45 @@ private function internalQuerySelector(string $selector)
 
     /**
      * Returns a list of document elements matching the selector
-     *
+     * 
      * @param string $selector CSS query selector
      * @param int|null $preferredLimit Preferred maximum number of elements to return
-     * @return \DOMNodeList Returns a list of DOMElements matching the criteria
+     * @return DOMNodeList Returns a list of DOMElements matching the criteria
      * @throws \InvalidArgumentException
      */
     private function internalQuerySelectorAll(string $selector, $preferredLimit = null)
     {
-        $walkChildren = function($element, $callback) use (&$walkChildren) { // $walkChildren is a lot faster than $this->getElementsByTagName('*') for 300+ elements
-            foreach ($element->childNodes as $child) {
-                if ($child instanceof \DOMElement) {
+        $walkChildren = function($element, $tagName, $callback) use (&$walkChildren) { // $walkChildren is a lot faster than $this->getElementsByTagName('*') for 300+ elements
+            if ($tagName !== null) {
+                $children = $element->getElementsByTagName($tagName);
+                foreach ($children as $child) {
                     if ($callback($child) === true) {
                         return true;
                     }
-                    if ($walkChildren($child, $callback) === true) {
-                        return true;
+                }
+            } else {
+                foreach ($element->childNodes as $child) {
+                    if ($child instanceof \DOMElement) {
+                        if ($callback($child) === true) {
+                            return true;
+                        }
+                        if ($walkChildren($child, $tagName, $callback) === true) {
+                            return true;
+                        }
                     }
                 }
             }
         };
 
-        $getElementById = function($id) use (&$walkChildren) {
+        $getElementById = function($id, $tagName) use (&$walkChildren) {
             if ($this instanceof \DOMDocument) {
-                return $this->getElementById($id);
+                $element = $this->getElementById($id);
+                if ($element && ($tagName === null || $element->tagName === $tagName)) {
+                    return $element;
+                }
             } else {
                 $foundElement = null;
-                $walkChildren($this, function($element) use ($id, &$foundElement) {
+                $walkChildren($this, $tagName, function($element) use ($id, &$foundElement) {
                     if ($element->attributes->length > 0 && $element->getAttribute('id') === $id) {
                         $foundElement = $element;
                         return true;
@@ -59,28 +71,30 @@ private function internalQuerySelectorAll(string $selector, $preferredLimit = nu
         $matches = null;
         if ($selector === '*') { // all
             $result = [];
-            $walkChildren($this, function($element) use (&$result) {
+            $walkChildren($this, null, function($element) use (&$result, $preferredLimit) {
                 $result[] = $element;
+                if ($preferredLimit !== null && sizeof($result) >= $preferredLimit) {
+                    return true;
+                }
             });
             return new \IvoPetkov\HTML5DOMNodeList($result);
         } elseif (preg_match('/^[a-z0-9]+$/', $selector) === 1) { // tagname
             $result = [];
-            $walkChildren($this, function($element) use (&$result, $selector) {
-                if ($element->tagName === $selector) {
-                    $result[] = $element;
+            $walkChildren($this, $selector, function($element) use (&$result, $preferredLimit) {
+                $result[] = $element;
+                if ($preferredLimit !== null && sizeof($result) >= $preferredLimit) {
+                    return true;
                 }
             });
             return new \IvoPetkov\HTML5DOMNodeList($result);
         } elseif (preg_match('/^([a-z0-9]*)\[(.+)\=\"(.+)\"\]$/', $selector, $matches) === 1) { // tagname[attribute="value"] or [attribute="value"]
             $result = [];
             $tagName = strlen($matches[1]) > 0 ? $matches[1] : null;
-            $walkChildren($this, function($element) use (&$result, $tagName, $preferredLimit, $matches) {
-                if ($tagName === null || $element->tagName === $tagName) {
-                    if ($element->attributes->length > 0 && $element->getAttribute($matches[2]) === $matches[3]) {
-                        $result[] = $element;
-                        if ($preferredLimit !== null && sizeof($result) >= $preferredLimit) {
-                            return true;
-                        }
+            $walkChildren($this, $tagName, function($element) use (&$result, $preferredLimit, $matches) {
+                if ($element->attributes->length > 0 && $element->getAttribute($matches[2]) === $matches[3]) {
+                    $result[] = $element;
+                    if ($preferredLimit !== null && sizeof($result) >= $preferredLimit) {
+                        return true;
                     }
                 }
             });
@@ -88,18 +102,17 @@ private function internalQuerySelectorAll(string $selector, $preferredLimit = nu
         } elseif (preg_match('/^([a-z0-9]*)#(.+)$/', $selector, $matches) === 1) { // tagname#id or #id
             $tagName = strlen($matches[1]) > 0 ? $matches[1] : null;
             $idSelector = $matches[2];
-            $element = $getElementById($idSelector);
-            if ($element && ($tagName === null || $element->tagName === $tagName)) {
+            $element = $getElementById($idSelector, $tagName);
+            if ($element) {
                 return new \IvoPetkov\HTML5DOMNodeList([$element]);
             }
             return new \IvoPetkov\HTML5DOMNodeList();
         } elseif (preg_match('/^([a-z0-9]*)\.(.+)$/', $selector, $matches) === 1) { // tagname.classname or .classname
-            $parts = explode('.', $selector, 2);
             $tagName = strlen($matches[1]) > 0 ? $matches[1] : null;
             $classSelector = $matches[2];
             $result = [];
-            $walkChildren($this, function($element) use (&$result, $tagName, $classSelector, $preferredLimit) {
-                if (($tagName === null || $element->tagName === $tagName) && $element->attributes->length > 0) {
+            $walkChildren($this, $tagName, function($element) use (&$result, $classSelector, $preferredLimit) {
+                if ($element->attributes->length > 0) {
                     $classAttribute = $element->getAttribute('class');
                     if ($classAttribute === $classSelector || strpos($classAttribute, $classSelector . ' ') === 0 || substr($classAttribute, -(strlen($classSelector) + 1)) === ' ' . $classSelector || strpos($classAttribute, ' ' . $classSelector . ' ') !== false) {
                         $result[] = $element;