CallTimePassByReferenceSniff.php

<?php
/**
 * Ensures that variables are not passed by reference when calling a function.
 *
 * @author    Florian Grandel <jerico.dev@gmail.com>
 * @copyright 2009-2014 Florian Grandel
 * @license   https://github.com/squizlabs/PHP_CodeSniffer/blob/master/licence.txt BSD Licence
 */

namespace PHP_CodeSniffer\Standards\Generic\Sniffs\Functions;

use PHP_CodeSniffer\Sniffs\Sniff;
use PHP_CodeSniffer\Files\File;
use PHP_CodeSniffer\Util\Tokens;

class CallTimePassByReferenceSniff implements Sniff
{


    /**
     * Returns an array of tokens this test wants to listen for.
     *
     * @return array
     */
    public function register()
    {
        return array(
                T_STRING,
                T_VARIABLE,
               );

    }//end register()


    /**
     * Processes this test, when one of its tokens is encountered.
     *
     * @param \PHP_CodeSniffer\Files\File $phpcsFile The file being scanned.
     * @param int                         $stackPtr  The position of the current token
     *                                               in the stack passed in $tokens.
     *
     * @return void
     */
    public function process(File $phpcsFile, $stackPtr)
    {
        $tokens = $phpcsFile->getTokens();

        $findTokens = array_merge(
            Tokens::$emptyTokens,
            array(T_BITWISE_AND)
        );

        $prev = $phpcsFile->findPrevious($findTokens, ($stackPtr - 1), null, true);

        // Skip tokens that are the names of functions or classes
        // within their definitions. For example: function myFunction...
        // "myFunction" is T_STRING but we should skip because it is not a
        // function or method *call*.
        $prevCode = $tokens[$prev]['code'];
        if ($prevCode === T_FUNCTION || $prevCode === T_CLASS) {
            return;
        }

        // If the next non-whitespace token after the function or method call
        // is not an opening parenthesis then it cant really be a *call*.
        $functionName = $stackPtr;
        $openBracket  = $phpcsFile->findNext(
            Tokens::$emptyTokens,
            ($functionName + 1),
            null,
            true
        );

        if ($tokens[$openBracket]['code'] !== T_OPEN_PARENTHESIS) {
            return;
        }

        if (isset($tokens[$openBracket]['parenthesis_closer']) === false) {
            return;
        }

        $closeBracket = $tokens[$openBracket]['parenthesis_closer'];

        $nextSeparator = $openBracket;
        $find          = array(
                          T_VARIABLE,
                          T_OPEN_SHORT_ARRAY,
                         );

        while (($nextSeparator = $phpcsFile->findNext($find, ($nextSeparator + 1), $closeBracket)) !== false) {
            if (isset($tokens[$nextSeparator]['nested_parenthesis']) === false) {
                continue;
            }

            if ($tokens[$nextSeparator]['code'] === T_OPEN_SHORT_ARRAY) {
                $nextSeparator = $tokens[$nextSeparator]['bracket_closer'];
                continue;
            }

            // Make sure the variable belongs directly to this function call
            // and is not inside a nested function call or array.
            $brackets    = $tokens[$nextSeparator]['nested_parenthesis'];
            $lastBracket = array_pop($brackets);
            if ($lastBracket !== $closeBracket) {
                continue;
            }

            // Checking this: $value = my_function(...[*]$arg...).
            $tokenBefore = $phpcsFile->findPrevious(
                Tokens::$emptyTokens,
                ($nextSeparator - 1),
                null,
                true
            );

            if ($tokens[$tokenBefore]['code'] === T_BITWISE_AND) {
                // Checking this: $value = my_function(...[*]&$arg...).
                $tokenBefore = $phpcsFile->findPrevious(
                    Tokens::$emptyTokens,
                    ($tokenBefore - 1),
                    null,
                    true
                );

                // We have to exclude all uses of T_BITWISE_AND that are not
                // references. We use a blacklist approach as we prefer false
                // positives to not identifying a pass-by-reference call at all.
                $tokenCode = $tokens[$tokenBefore]['code'];
                if ($tokenCode === T_VARIABLE
                    || $tokenCode === T_CLOSE_PARENTHESIS
                    || $tokenCode === T_CLOSE_SQUARE_BRACKET
                    || $tokenCode === T_LNUMBER
                    || isset(Tokens::$assignmentTokens[$tokenCode]) === true
                ) {
                    continue;
                }

                // T_BITWISE_AND represents a pass-by-reference.
                $error = 'Call-time pass-by-reference calls are prohibited';
                $phpcsFile->addError($error, $tokenBefore, 'NotAllowed');
            }//end if
        }//end while

    }//end process()


}//end class