DoubleQuoteUsageSniff

<?php
/**
 * Zend_Sniffs_Strings_DoubleQuoteUsageSniff.
 *
 * PHP version 5
 *
 * @category  PHP
 * @package   PHP_CodeSniffer
 * @author    Juan Sotuyo <juansotuyo@gmail.com>
 * @copyright 2010 Juan Sotuyo (Buenos Aires, Argentina)
 * @license   BSD Licence
 * @version   1.0
 * @link      http://pear.php.net/package/PHP_CodeSniffer
 */

/**
 * Zend_Sniffs_Strings_DoubleQuoteUsageSniff.
 *
 * Makes sure that any use of Double Quotes ("") are warranted.
 *
 * @category  PHP
 * @package   PHP_CodeSniffer
 * @author    Juan Sotuyo <juansotuyo@gmail.com>
 * @copyright 2010 Juan Sotuyo (Buenos Aires, Argentina)
 * @license   BSD Licence
 * @version   Release: 1.2.2
 * @link      http://pear.php.net/package/PHP_CodeSniffer
 */
class Zend_Sniffs_Strings_DoubleQuoteUsageSniff implements PHP_CodeSniffer_Sniff
{

    protected static $allowedChars = array(
                         '\0',
                         '\n',
                         '\r',
                         '\f',
                         '\t',
                         '\v',
                         '\x',
                        );

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

    }//end register()


    /**
     * Processes this test, when one of its tokens is encountered.
     *
     * @param PHP_CodeSniffer_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(PHP_CodeSniffer_File $phpcsFile, $stackPtr)
    {
        $tokens = $phpcsFile->getTokens();
        $string = $tokens[$stackPtr]['content'];

        $varFound = false;

        // The use of variables in double quoted strings is not allowed.
        if ($tokens[$stackPtr]['code'] === T_DOUBLE_QUOTED_STRING) {
            $stringTokens = token_get_all('<?php '.$string);
            foreach ($stringTokens as $token) {
                if (is_array($token) === true && $token[0] === T_VARIABLE) {
                    $varFound = true;
                }
            }
        }

        // Check the var is not in the "${...}" format
        $matches = preg_match('/\$\{[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*\}/', $string);
        if ($matches !== false && $matches > 0) {
            $error = 'String "'.$string.'" contains a variable in the format: ${variable} which is not allowed; use no braces or {$var} instead';
            $phpcsFile->addError($error, $stackPtr);
        }

        if ($varFound) {
            return;
        }

        // Are apostrophes included in the string?
        if (strstr($string, "'") !== false) {
            return;
        }

        foreach (self::$allowedChars as $char) {
            if (strstr($string, $char) !== false) {
                return;
            }
        }

        $error = 'String '.$string.' dows not require double quotes; use single quotes instead.';
        $phpcsFile->addError($error, $stackPtr);
    }//end process()


}//end class

?>