[Kde-pim] parseRFCDate/parseISODate - wrong bad date handling (PATCH)

[David Jarvie]

On Wednesday 16 July 2008 14:44, Michal Hlaivnka wrote:
> Allen Winter napsal(a):
>> On Wednesday 16 July 2008 07:48:32 David Jarvie wrote:
>>
>>> On Wednesday 16 July 2008 12:27, masp01 at centrum.cz wrote:
>>>
>>>> Hi,
>>>>
>>>> I've found bug in kdepimlibs/syndication/tools.cpp (bugs.kde.org -
>>>> 166721)
>>>>
>>>> description: if string contains date in wrong format, parseRFCDate (or
>>>> parseISODate) returns 2^32-1
>>>>
>>>>  result: some apps (akregator) don't know about error, because
>>>> returned
>>>> value uint32_t(-1) is not the expected time_t(-1) ( = uint64_t(-1) at
>>>> least on my computer). This leads to wrong dates being displayed
>>>>
>>>>  Problem is located between Qt 4 and KDateTime.
>>>>
>>>>  KDateTime::toTime_t() returns time_t (64bit at least on my computer)
>>>>  but
>>>>  QDateTime::toTime_t() returns uint (32bit)
>>>>
>>>>  QDateTime's -1 is converted to 4294967295, but error is tested for -1
>>>>
>>>>  solution: QDateTime's return type should be time_t, not uint
>>>>
>>>>  fix: Don't test for -1 but do QDateTime/KDateTime::isValid() tests
>>>>
>>>>
>>>> patch to fix this is attached
>>>>
>>>>
>>>>  time_t parseISODate(const QString& str)
>>>>  {
>>>> -    time_t res = KDateTime::fromString(str,
>>>>
>>> KDateTime::ISODate).toTime_t();
>>>
>>>> -    return res != -1 ? res : 0;
>>>> +    const KDateTime kdt = KDateTime::fromString(str,
>>>> KDateTime::ISODate);
>>>> +    return kdt.isValid() ? kdt.toTime_t() : 0;
>>>>  }
>>>>
>>>>  time_t parseRFCDate(const QString& str)
>>>>  {
>>>> -    time_t res = KDateTime::fromString(str,
>>>>
>>> KDateTime::RFCDate).toTime_t();
>>>
>>>> -    return res != -1 ? res : 0;
>>>> +    const KDateTime kdt = KDateTime::fromString(str,
>>>> KDateTime::RFCDate);
>>>> +    return kdt.isValid() ? kdt.toTime_t() : 0;
>>>>  }
>>>>
>>>>  time_t parseDate(const QString& str, DateFormat hint)
>>>>
>>> How about casting the -1 to time_t in the return statements instead:
>>>
>>>    return res != (time_t)(-1) ? res : 0;
>>>
> It won't work. res is time_t( uint(-1) ), so '-1' in the statement is
> already time_t(-1)

Actually, I just checked and KDateTime::toTime_t() returns a uint the same
as QDateTime::toTime_t(). See the apidox (which does correspond to the
source code :) ). So the return statement should presumably be

    return uint(res) != uint(-1) ? res : 0;

Of course, if time_t is signed (as it is on some systems), the return
value won't be correct if the m.s. bit is set.

-- 
David Jarvie.
KAlarm author & maintainer.
http://www.astrojar.org.uk/kalarm

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