Re-implement ParserState anchors with dedicated Anchor class

Author: raxbg

src/Parsing/Anchor.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace Sabberworm\CSS\Parsing;
+
+class Anchor
+{
+    /**
+     * @var int
+     */
+    private $iPosition;
+
+    /**
+     * @var \Sabberworm\CSS\Parsing\ParserState
+     */
+    private $oParserState;
+
+    /**
+     * @param int $iPosition
+     * @param \Sabberworm\CSS\Parsing\ParserState $oParserState
+     */
+    public function __construct($iPosition, ParserState $oParserState)
+    {
+        $this->iPosition = $iPosition;
+        $this->oParserState = $oParserState;
+    }
+
+    /**
+     * @return void
+     */
+    public function backtrack()
+    {
+        $this->oParserState->setPosition($this->iPosition);
+    }
+}

src/Parsing/ParserState.php

@@ -49,11 +49,6 @@ class ParserState
      */
     private $iLineNo;
 
-    /**
-     * @var int
-     */
-    private $iAnchor;
-
     /**
      * @param string $sText the complete CSS as text (i.e., usually the contents of a CSS file)
      * @param int $iLineNo
@@ -64,7 +59,6 @@ public function __construct($sText, Settings $oParserSettings, $iLineNo = 1)
         $this->sText = $sText;
         $this->iCurrentPosition = 0;
         $this->iLineNo = $iLineNo;
-        $this->iAnchor = null;
         $this->setCharset($this->oParserSettings->sDefaultCharset);
     }
 
@@ -118,16 +112,22 @@ public function getSettings()
         return $this->oParserSettings;
     }
 
-    public function setAnchor()
+    /**
+     * @return \Sabberworm\CSS\Parsing\Anchor
+     */
+    public function anchor()
     {
-        $this->iAnchor = $this->iCurrentPosition;
+        return new Anchor($this->iCurrentPosition, $this);
     }
 
-    public function backtrackToAnchor()
+    /**
+     * @param int $iPosition
+     *
+     * @return void
+     */
+    public function setPosition($iPosition)
     {
-        if ($this->iAnchor !== null) {
-            $this->iCurrentPosition = $this->iAnchor;
-        }
+        $this->iCurrentPosition = $iPosition;
     }
 
     /**

src/Value/URL.php

@@ -36,7 +36,7 @@ public function __construct(CSSString $oURL, $iLineNo = 0)
      */
     public static function parse(ParserState $oParserState)
     {
-        $oParserState->setAnchor();
+        $oAnchor = $oParserState->anchor();
         $sIdentifier = '';
         for ($i = 0; $i < 3; $i++) {
             $sChar = $oParserState->parseCharacter(true);
@@ -50,7 +50,7 @@ public static function parse(ParserState $oParserState)
             $oParserState->consumeWhiteSpace();
             $oParserState->consume('(');
         } else {
-            $oParserState->backtrackToAnchor();
+            $oAnchor->backtrack();
         }
         $oParserState->consumeWhiteSpace();
         $oResult = new URL(CSSString::parse($oParserState), $oParserState->currentLine());

src/Value/Value.php

@@ -106,15 +106,15 @@ public static function parseValue(ParserState $oParserState, array $aListDelimit
      */
     public static function parseIdentifierOrFunction(ParserState $oParserState, $bIgnoreCase = false)
     {
-        $oParserState->setAnchor();
+        $oAnchor = $oParserState->anchor();
         $mResult = $oParserState->parseIdentifier($bIgnoreCase);
 
         if ($oParserState->comes('(')) {
             if ($oParserState->streql('url', $mResult)) {
-                $oParserState->backtrackToAnchor();
+                $oAnchor->backtrack();
                 $mResult = URL::parse($oParserState);
             } else if ($oParserState->streql('calc', $mResult) || $oParserState->streql('-webkit-calc', $mResult) || $oParserState->streql('-moz-calc', $mResult)) {
-                $oParserState->backtrackToAnchor();
+                $oAnchor->backtrack();
                 $mResult = CalcFunction::parse($oParserState);
             } else {
                 $oParserState->consume('(');