add support for inline style css functions

Author: garg23neha

src/main/java/org/owasp/validator/css/CssValidator.java

@@ -361,10 +361,23 @@ public String lexicalValueToString(LexicalUnit lu) {
         return "inherit";
       case LexicalUnit.SAC_OPERATOR_COMMA:
         return ",";
+      case LexicalUnit.SAC_FUNCTION:
+        final StringBuffer builder = new StringBuffer();
+        builder.append(lu.getFunctionName());
+        builder.append("(");
+        LexicalUnit params = lu.getParameters();
+        while (params != null) {
+          builder.append(lexicalValueToString(params));
+          params = params.getNextLexicalUnit();
+          if (params != null) {
+            builder.append(", ");
+          }
+        }
+        builder.append(")");
+        return builder.toString();
       case LexicalUnit.SAC_ATTR:
       case LexicalUnit.SAC_COUNTER_FUNCTION:
       case LexicalUnit.SAC_COUNTERS_FUNCTION:
-      case LexicalUnit.SAC_FUNCTION:
       case LexicalUnit.SAC_RECT_FUNCTION:
       case LexicalUnit.SAC_SUB_EXPRESSION:
       case LexicalUnit.SAC_UNICODERANGE:

src/test/java/org/owasp/validator/css/CssValidatorTest.java

@@ -0,0 +1,51 @@
+package org.owasp.validator.css;
+
+import org.apache.batik.css.parser.CSSLexicalUnit;
+import org.junit.Test;
+import org.w3c.css.sac.LexicalUnit;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+
+public class CssValidatorTest {
+    @Test
+    public void testLexicalValueToStringSacFunction() {
+        CssValidator cssValidator = new CssValidator(null);
+
+        final CSSLexicalUnit param =
+                CSSLexicalUnit.createString(LexicalUnit.SAC_STRING_VALUE, "--ds-text-purple", null);
+        final CSSLexicalUnit varFunc = CSSLexicalUnit.createFunction("var", param, null);
+
+        assertEquals("var(--ds-text-purple)", cssValidator.lexicalValueToString(varFunc));
+
+        final CSSLexicalUnit hslaParam = CSSLexicalUnit.createInteger(100, null);
+        final CSSLexicalUnit hslaParam1 = CSSLexicalUnit.createDimension(98, "%", hslaParam);
+        final CSSLexicalUnit hslaParam2 = CSSLexicalUnit.createDimension(50, "%", hslaParam1);
+        CSSLexicalUnit.createFloat(LexicalUnit.SAC_REAL, 0.3f, hslaParam2);
+
+        final CSSLexicalUnit hslaFunc = CSSLexicalUnit.createFunction("hsla", hslaParam, null);
+        assertEquals("hsla(100, 98.0%, 50.0%, 0.3)", cssValidator.lexicalValueToString(hslaFunc));
+    }
+
+    @Test
+    public void testLexicalValueToStringSacFunctionTwoParams() {
+        CssValidator cssValidator = new CssValidator(null);
+
+        final CSSLexicalUnit param =
+                CSSLexicalUnit.createString(LexicalUnit.SAC_STRING_VALUE, "--ds-text-purple", null);
+        CSSLexicalUnit.createString(LexicalUnit.SAC_STRING_VALUE, "#FFFFFF", param);
+        final CSSLexicalUnit func = CSSLexicalUnit.createFunction("var", param, null);
+
+        assertEquals("var(--ds-text-purple, #FFFFFF)", cssValidator.lexicalValueToString(func));
+    }
+
+    @Test
+    public void testLexicalValueToStringUnsupported() {
+        CssValidator cssValidator = new CssValidator(null);
+        final CSSLexicalUnit param =
+                CSSLexicalUnit.createString(LexicalUnit.SAC_STRING_VALUE, "section", null);
+        final CSSLexicalUnit func =
+                CSSLexicalUnit.createPredefinedFunction(LexicalUnit.SAC_COUNTER_FUNCTION, param, null);
+        assertNull(cssValidator.lexicalValueToString(func));
+    }
+}