PhpCsFixer\Fixer\Comment\HeaderCommentFixer::fix PHP Method

    public function fix(\SplFileInfo $file, Tokens $tokens)
    {
        if (null === $this->headerComment) {
            throw new RequiredFixerConfigurationException($this->getName(), 'Configuration is required.');
        }
        // figure out where the comment should be placed
        $headerNewIndex = $this->findHeaderCommentInsertionIndex($tokens);
        // check if there is already a comment
        $headerCurrentIndex = $this->findHeaderCommentCurrentIndex($tokens, $headerNewIndex - 1);
        if (null === $headerCurrentIndex) {
            if ('' === $this->headerComment) {
                return;
                // header not found and none should be set, return
            }
            $this->insertHeader($tokens, $headerNewIndex);
        } elseif ($this->headerComment !== $tokens[$headerCurrentIndex]->getContent()) {
            $tokens->clearTokenAndMergeSurroundingWhitespace($headerCurrentIndex);
            if ('' === $this->headerComment) {
                return;
                // header found and cleared, none should be set, return
            }
            $this->insertHeader($tokens, $headerNewIndex);
        } else {
            $headerNewIndex = $headerCurrentIndex;
        }
        $this->fixWhiteSpaceAroundHeader($tokens, $headerNewIndex);
    }