[Phpmyadmin-devel] about $common_functions

[Rouslan Placella]

On 03/07/12 15:05, Marc Delisle wrote:
> Le 2012-07-03 10:00, Rouslan Placella a écrit :
>> On 03/07/12 14:51, Marc Delisle wrote:
>>> Le 2012-07-03 09:38, Rouslan Placella a écrit :
>>>> On 03/07/12 14:34, Marc Delisle wrote:
>>>>> Hi,
>>>>> I just made a suggestion to Thilina but I want to validate it with
>>>>> everyone.
>>>>>
>>>>> I see a lot of
>>>>> $common_functions = PMA_CommonFunctions::getInstance()
>>>>>
>>>>> inside many functions of the same library. If we know that this library
>>>>> is always called from one script, I believe it would be more efficient
>>>>> to do this instead, inside the functions:
>>>>>
>>>>> global $common_functions;
>>>>>
>>>>> and ensure that $common_functions has been defined in the global scope
>>>>> of the calling script.
>>>>>
>>>>
>>>> Doesn't that defeat the purpose of having a singleton class?
>>>
>>> Well, I don't understand the definition of a singleton. From [0],
>>> "the singleton pattern is a design pattern that restricts the
>>> instantiation of a class to one object"
>>>
>>> Does that mean that one such object must exist inside a function, or
>>> must exist considering all scopes?
>>
>> There will be only one in all scopes. However I thought that we were
>> trying to reduce the number of globals that we have, since sometimes we
>> get problems with undefined globals. Also, if we have a global reference
>> to the commonFunctions object, then I see no point in restricting the
>> number of instances.
>
> Ok, so what do you think of this code snippet:
>
> $query[] = $insert_command . 'INTO '
>   . PMA_CommonFunctions::getInstance()->backquote($GLOBALS['db']) . '.'
>   . PMA_CommonFunctions::getInstance()->backquote($GLOBALS['table'])
>          . ' (' . implode(', ', $query_fields) . ') VALUES ('
>          . implode('), (', $value_sets) . ')';
>
> Does this follow the singleton principle?

I don't know about following the principle, but it looks ugly. There 
should definitely be a local reference to the commonFunctions object.

$commonFunctions = PMA_CommonFunctions::getInstance();
$query[] = $insert_command . 'INTO '
    . $commonFunctions->backquote($GLOBALS['db']) . '.'
    . $commonFunctions->backquote($GLOBALS['table'])
           . ' (' . implode(', ', $query_fields) . ') VALUES ('
           . implode('), (', $value_sets) . ')';