getInstance Comparision

existing.php

public static function getInstance($options = array())
{
	// Sanitize the database connector options.
	$options['driver']   = (isset($options['driver'])) ? preg_replace('/[^A-Z0-9_\.-]/i', '', $options['driver']) : 'mysqli';
	$options['database'] = (isset($options['database'])) ? $options['database'] : null;
	$options['select']   = (isset($options['select'])) ? $options['select'] : true;

	// If the selected driver is `mysql` and we are on PHP 7 or greater, switch to the `mysqli` driver.
	if ($options['driver'] === 'mysql' && PHP_MAJOR_VERSION >= 7)
	{
		// Check if we have support for the other MySQL drivers
		$mysqliSupported   = JDatabaseDriverMysqli::isSupported();
		$pdoMysqlSupported = JDatabaseDriverPdomysql::isSupported();

		// If neither is supported, then the user cannot use MySQL; throw an exception
		if (!$mysqliSupported && !$pdoMysqlSupported)
		{
			throw new RuntimeException(
				'The PHP `ext/mysql` extension is removed in PHP 7, cannot use the `mysql` driver.'
				. ' Also, this system does not support MySQLi or PDO MySQL.  Cannot instantiate database driver.'
			);
		}

		// Prefer MySQLi as it is a closer replacement for the removed MySQL driver, otherwise use the PDO driver
		if ($mysqliSupported)
		{
			JLog::add(
				'The PHP `ext/mysql` extension is removed in PHP 7, cannot use the `mysql` driver.  Trying `mysqli` instead.',
				JLog::WARNING,
				'deprecated'
			);

			$options['driver'] = 'mysqli';
		}
		else
		{
			JLog::add(
				'The PHP `ext/mysql` extension is removed in PHP 7, cannot use the `mysql` driver.  Trying `pdomysql` instead.',
				JLog::WARNING,
				'deprecated'
			);

			$options['driver'] = 'pdomysql';
		}
	}

	// Get the options signature for the database connector.
	$signature = md5(serialize($options));

	// If we already have a database connector instance for these options then just use that.
	if (empty(self::$instances[$signature]))
	{
		// Derive the class name from the driver.
		$class = 'JDatabaseDriver' . ucfirst(strtolower($options['driver']));

		// If the class still doesn't exist we have nothing left to do but throw an exception.  We did our best.
		if (!class_exists($class))
		{
			throw new RuntimeException(sprintf('Unable to load Database Driver: %s', $options['driver']));
		}

		// Create our new JDatabaseDriver connector based on the options given.
		try
		{
			$instance = new $class($options);
		}
		catch (RuntimeException $e)
		{
			throw new RuntimeException(sprintf('Unable to connect to the Database: %s', $e->getMessage()));
		}

		// Set the new connector to the global instances based on signature.
		self::$instances[$signature] = $instance;
	}

	return self::$instances[$signature];
}

modified.php

public static function getInstance($options = array())
{
	// Sanitize the database connector options.
	$options['driver']   = (isset($options['driver'])) ? preg_replace('/[^A-Z0-9_\.-]/i', '', $options['driver']) : 'mysqli';
	$options['database'] = (isset($options['database'])) ? $options['database'] : null;
	$options['select']   = (isset($options['select'])) ? $options['select'] : true;

	// If the selected driver is `mysql` and we are on PHP 7 or greater, switch to the `mysqli` driver.
	// START MODIFICATION
	$isPhp7 = PHP_MAJOR_VERSION >= 7;
	$isDeprecatedMysql = $options['driver'] === 'mysql';
	
	if ($isPhp7 && $isDeprecatedMysql)
	// END MODIFICATION
	{
		// Check if we have support for the other MySQL drivers
		$mysqliSupported   = JDatabaseDriverMysqli::isSupported();
		$pdoMysqlSupported = JDatabaseDriverPdomysql::isSupported();

		// If neither is supported, then the user cannot use MySQL; throw an exception
		if (!$mysqliSupported && !$pdoMysqlSupported)
		{
			throw new RuntimeException(
				'The PHP `ext/mysql` extension is removed in PHP 7, cannot use the `mysql` driver.'
				. ' Also, this system does not support MySQLi or PDO MySQL.  Cannot instantiate database driver.'
			);
		}

		// Prefer MySQLi as it is a closer replacement for the removed MySQL driver, otherwise use the PDO driver
		if ($mysqliSupported)
		{
			JLog::add(
				'The PHP `ext/mysql` extension is removed in PHP 7, cannot use the `mysql` driver.  Trying `mysqli` instead.',
				JLog::WARNING,
				'deprecated'
			);

			$options['driver'] = 'mysqli';
		}
		else
		{
			JLog::add(
				'The PHP `ext/mysql` extension is removed in PHP 7, cannot use the `mysql` driver.  Trying `pdomysql` instead.',
				JLog::WARNING,
				'deprecated'
			);

			$options['driver'] = 'pdomysql';
		}
	}

	// Get the options signature for the database connector.
	$signature = md5(serialize($options));

	// If we already have a database connector instance for these options then just use that.
	if (empty(self::$instances[$signature]))
	{
		// Derive the class name from the driver.
		$class = 'JDatabaseDriver' . ucfirst(strtolower($options['driver']));

		// If the class still doesn't exist we have nothing left to do but throw an exception.  We did our best.
		if (!class_exists($class))
		{
			throw new RuntimeException(sprintf('Unable to load Database Driver: %s', $options['driver']));
		}

		// Create our new JDatabaseDriver connector based on the options given.
		try
		{
			$instance = new $class($options);
		}
		catch (RuntimeException $e)
		{
			throw new RuntimeException(sprintf('Unable to connect to the Database: %s', $e->getMessage()));
		}

		// Set the new connector to the global instances based on signature.
		self::$instances[$signature] = $instance;
	}

	return self::$instances[$signature];
}