Support for IE hack parsing in lenient mode

This allows for \0 and \9 to remain as they are intended. And will
throw an exception when they are found in strict mode.

Author: Frederic Massart

lib/Sabberworm/CSS/Parser.php

@@ -255,6 +255,10 @@ private function parseStringValue() {
 
 	private function parseCharacter($bIsForIdentifier) {
 		if ($this->peek() === '\\') {
+			if ($bIsForIdentifier && $this->oParserSettings->bLenientParsing && ($this->comes('\0') || $this->comes('\9'))) {
+				// Non-strings can contain \0 or \9 which is an IE hack supported in lenient parsing.
+				return null;
+			}
 			$this->consume('\\');
 			if ($this->comes('\n') || $this->comes('\r')) {
 				return '';
@@ -350,6 +354,13 @@ private function parseRule() {
 		$this->consume(':');
 		$oValue = $this->parseValue(self::listDelimiterForRule($oRule->getRule()));
 		$oRule->setValue($oValue);
+		if ($this->oParserSettings->bLenientParsing) {
+			while ($this->comes('\\')) {
+				$this->consume('\\');
+				$oRule->addIeHack($this->consume());
+				$this->consumeWhiteSpace();
+			}
+		}
 		if ($this->comes('!')) {
 			$this->consume('!');
 			$this->consumeWhiteSpace();
@@ -367,7 +378,7 @@ private function parseValue($aListDelimiters) {
 		$aStack = array();
 		$this->consumeWhiteSpace();
 		//Build a list of delimiters and parsed values
-		while (!($this->comes('}') || $this->comes(';') || $this->comes('!') || $this->comes(')'))) {
+		while (!($this->comes('}') || $this->comes(';') || $this->comes('!') || $this->comes(')') || $this->comes('\\'))) {
 			if (count($aStack) > 0) {
 				$bFoundDelimiter = false;
 				foreach ($aListDelimiters as $sDelimiter) {

lib/Sabberworm/CSS/Rule/Rule.php

@@ -15,12 +15,14 @@ class Rule implements Renderable {
 	private $sRule;
 	private $mValue;
 	private $bIsImportant;
+	private $aIeHack;
 	protected $iLineNo;
 
 	public function __construct($sRule, $iLineNo = 0) {
 		$this->sRule = $sRule;
 		$this->mValue = null;
 		$this->bIsImportant = false;
+		$this->aIeHack = array();
 		$this->iLineNo = $iLineNo;
 	}
 
@@ -127,6 +129,18 @@ public function addValue($mValue, $sType = ' ') {
 		}
 	}
 
+	public function addIeHack($iModifier) {
+		$this->aIeHack[] = $iModifier;
+	}
+
+	public function setIeHack(array $aModifiers) {
+		$this->aIeHack = $aModifiers;
+	}
+
+	public function getIeHack() {
+		return $this->aIeHack;
+	}
+
 	public function setIsImportant($bIsImportant) {
 		$this->bIsImportant = $bIsImportant;
 	}
@@ -146,6 +160,9 @@ public function render(\Sabberworm\CSS\OutputFormat $oOutputFormat) {
 		} else {
 			$sResult .= $this->mValue;
 		}
+		if (!empty($this->aIeHack)) {
+			$sResult .= ' \\' . implode('\\', $this->aIeHack);
+		}
 		if ($this->bIsImportant) {
 			$sResult .= ' !important';
 		}

tests/Sabberworm/CSS/ParserTest.php

@@ -505,4 +505,18 @@ function testUnexpectedTokenExceptionLineNo() {
 			throw $e;
 		}
 	}
+
+	/**
+	* @expectedException Sabberworm\CSS\Parsing\UnexpectedTokenException
+	*/
+	function testIeHacksStrictParsing() {
+		// We can't strictly parse IE hacks.
+		$this->parsedStructureForFile('ie-hacks', Settings::create()->beStrict());
+	}
+
+	function testIeHacksParsing() {
+		$oDoc = $this->parsedStructureForFile('ie-hacks', Settings::create()->withLenientParsing(true));
+		$sExpected = 'p {padding-right: .75rem \9;background-image: none \9;color: red \9\0;background-color: red \9\0;background-color: red \9\0 !important;content: "red 	\0";content: "red઼";}';
+		$this->assertEquals($sExpected, $oDoc->render());
+	}
 }

tests/files/ie-hacks.css

@@ -0,0 +1,9 @@
+p {
+    padding-right: .75rem \9;
+    background-image: none \9;
+    color:red\9\0;
+    background-color:red \9 \0;
+    background-color:red \9 \0 !important;
+    content: "red \9\0";
+    content: "red\0abc";
+}