TASK: Do not check all classname parts for extension name

* As discussed in PR, fetch possible extension names and lookup only
  them, not all parts of class name.

Relates: #44, !70

src/Standards/Typo3Update/Feature/FeaturesSupport.php

@@ -21,12 +21,15 @@ namespace Typo3Update\Feature;
  */
 
 use PHP_CodeSniffer_File as PhpCsFile;
+use Typo3Update\Sniffs\ExtendedPhpCsSupportTrait;
 
 /**
  * Provides "feature" support for sniffs.
  */
 trait FeaturesSupport
 {
+    use ExtendedPhpCsSupportTrait;
+
     /**
      * @return Features
      */
@@ -44,6 +47,8 @@ trait FeaturesSupport
      */
     public function processFeatures(PhpCsFile $phpcsFile, $stackPtr, $content)
     {
+        $content = $this->getStringContent($content);
+
         foreach ($this->getFeatures() as $featureClassName) {
             $feature = $this->createFeature($featureClassName);
             $feature->process($phpcsFile, $stackPtr, $content);

src/Standards/Typo3Update/Feature/RemovedExtensionFeature.php

@@ -27,18 +27,8 @@ class RemovedExtensionFeature extends AbstractYamlRemovedUsage
 {
     public function process(PhpCsFile $phpcsFile, $classnamePosition, $classname)
     {
-        $classnameParts = array_filter(preg_split('/\\\\|_/', $classname));
-        $extname = '';
-
-        foreach ($classnameParts as $classnamePart) {
-            $classnamePart = strtolower($classnamePart);
-            if ($this->configured->isRemoved($classnamePart) === true) {
-                $extname = $classnamePart;
-                break;
-            }
-        }
-
-        if ($extname === '') {
+        $extname = $this->getExtnameFromClassname($classname);
+        if ($extname === '' || $this->configured->isRemoved($extname) === false) {
             return;
         }
 
@@ -49,6 +39,25 @@ class RemovedExtensionFeature extends AbstractYamlRemovedUsage
         );
     }
 
+    protected function getExtnameFromClassname($classname)
+    {
+        $classname = ltrim($classname, '\\');
+        $classnameParts = array_filter(preg_split('/\\\\|_/', $classname));
+        $classnameParts = array_values($classnameParts); // To reset key numbers of array.
+        $extname = '';
+
+        if (count($classnameParts) <= 2) {
+            return '';
+        }
+
+        $extname = $classnameParts[1];
+        if (stripos($classname, 'TYPO3\CMS') === 0) {
+            $extname = $classnameParts[2];
+        }
+
+        return strtolower($extname);
+    }
+
     protected function prepareStructure(array $typo3Versions)
     {
         $newStructure = [];