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Check POSIX rules during QTzTimeZone creation

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Previously, an apparent POSIX rule would be saved and any defects in
it would only be discovered when trying to use it to generate
transitions. Instead, check that it has the right form during the
initial parsing of its data.

In the process, since checking for DST in the process is trivial,
implement a long-standing TODO to cache hasDaylightTime()'s
answer. The array it scanned was in any case being scanned during
construction, so detecting DST in init()'s scan is trivial; and its
failure to check the POSIX rule mean it failed to notice when zones
entirely specified by a POSIX rule have DST.

Adapt a test using a POSIX-only rule to verify it does know the zone
has DST; it did not, before this change.

Change-Id: I690c013d3331600f7348dae61c35d41e5599da70
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This commit is contained in:
Edward Welbourne 2021-04-19 13:55:06 +02:00
parent 7fa8315eb1
commit 828f533b32
3 changed files with 66 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
src/corelib/time/qtimezoneprivate_p.h
View File

@ -301,6 +301,7 @@ struct QTzTimeZoneCacheEntry
QList<QByteArray> m_abbreviations;
QByteArray m_posixRule;
QTzTransitionRule m_preZoneRule;
bool m_hasDst;
};
class Q_AUTOTEST_EXPORT QTzTimeZonePrivate final : public QTimeZonePrivate

79
src/corelib/time/qtimezoneprivate_tz.cpp
View File

@ -555,7 +555,52 @@ PosixZone PosixZone::parse(const char *&pos, const char *end)
return {std::move(name), offset};
}
static QList<QTimeZonePrivate::Data> calculatePosixTransitions(const QByteArray &posixRule, int startYear, int endYear,
static auto validatePosixRule(const QByteArray &posixRule)
{
// Format is described here:
// http://www.gnu.org/software/libc/manual/html_node/TZ-Variable.html
// See also calculatePosixTransition()'s reference.
const auto parts = posixRule.split(',');
const struct { bool isValid, hasDst; } fail{false, false}, good{true, parts.count() > 1};
const QByteArray &zoneinfo = parts.at(0);
if (zoneinfo.isEmpty())
return fail;
const char *begin = zoneinfo.begin();
// Updates begin to point after the name and offset it parses:
if (PosixZone::parse(begin, zoneinfo.end()).name.isEmpty())
return fail;
if (good.hasDst) {
if (begin >= zoneinfo.end())
return fail;
// Expect a second name and offset after the first:
if (PosixZone::parse(begin, zoneinfo.end()).name.isEmpty())
return fail;
}
if (begin < zoneinfo.end())
return fail;
if (good.hasDst) {
if (parts.count() != 3 || parts.at(1).isEmpty() || parts.at(2).isEmpty())
return fail;
for (int i = 1; i < 3; ++i) {
const auto tran = parts.at(i).split('/');
if (!calculatePosixDate(tran.at(0), 1972).isValid())
return fail;
if (tran.count() > 1) {
const auto time = tran.at(1);
if (parsePosixTime(time.begin(), time.end()) == INT_MIN)
return fail;
}
}
}
return good;
}
static QList<QTimeZonePrivate::Data> calculatePosixTransitions(const QByteArray &posixRule,
int startYear, int endYear,
qint64 lastTranMSecs)
{
QList<QTimeZonePrivate::Data> result;
@ -564,6 +609,7 @@ static QList<QTimeZonePrivate::Data> calculatePosixTransitions(const QByteArray
// i.e. "std offset dst [offset],start[/time],end[/time]"
// See the section about TZ at
// http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html
// and the link in validatePosixRule(), above.
QList<QByteArray> parts = posixRule.split(',');
PosixZone stdZone, dstZone = PosixZone::invalid();
@ -727,11 +773,9 @@ QTzTimeZoneCacheEntry QTzTimeZoneCache::findEntry(const QByteArray &ianaId)
tzif.setFileName(QLatin1String("/usr/lib/zoneinfo/") + QString::fromLocal8Bit(ianaId));
if (!tzif.open(QIODevice::ReadOnly)) {
// ianaId may be a POSIX rule, taken from $TZ or /etc/TZ
const QByteArray zoneInfo = ianaId.split(',').at(0);
const char *begin = zoneInfo.constBegin();
if (PosixZone::parse(begin, zoneInfo.constEnd()).hasValidOffset()
&& (begin == zoneInfo.constEnd()
|| PosixZone::parse(begin, zoneInfo.constEnd()).hasValidOffset())) {
auto check = validatePosixRule(ianaId);
if (check.isValid) {
ret.m_hasDst = check.hasDst;
ret.m_posixRule = ianaId;
}
return ret;
@ -743,6 +787,7 @@ QTzTimeZoneCacheEntry QTzTimeZoneCache::findEntry(const QByteArray &ianaId)
// Parse the old version block of data
bool ok = false;
QByteArray posixRule;
QTzHeader hdr = parseTzHeader(ds, &ok);
if (!ok || ds.status() != QDataStream::Ok)
return ret;
@ -783,14 +828,21 @@ QTzTimeZoneCacheEntry QTzTimeZoneCache::findEntry(const QByteArray &ianaId)
typeList = parseTzIndicators(ds, typeList, hdr2.tzh_ttisstdcnt, hdr2.tzh_ttisgmtcnt);
if (ds.status() != QDataStream::Ok)
return ret;
ret.m_posixRule = parseTzPosixRule(ds);
posixRule = parseTzPosixRule(ds);
if (ds.status() != QDataStream::Ok)
return ret;
}
// Translate the TZ file's raw data into our internal form:
// Translate the TZ file into internal format
if (!posixRule.isEmpty()) {
auto check = validatePosixRule(posixRule);
if (!check.isValid) // We got a POSIX rule, but it was malformed:
return ret;
ret.m_posixRule = posixRule;
ret.m_hasDst = check.hasDst;
}
// Translate the array index based tz_abbrind into list index
// Translate the array-index-based tz_abbrind into list index
const int size = abbrevMap.size();
ret.m_abbreviations.clear();
ret.m_abbreviations.reserve(size);
@ -879,6 +931,8 @@ QTzTimeZoneCacheEntry QTzTimeZoneCache::findEntry(const QByteArray &ianaId)
// If the rule already exist then use that, otherwise add it
int ruleIndex = ret.m_tranRules.indexOf(rule);
if (ruleIndex == -1) {
if (rule.dstOffset != 0)
ret.m_hasDst = true;
ret.m_tranRules.append(rule);
tran.ruleIndex = ret.m_tranRules.size() - 1;
} else {
@ -1051,12 +1105,7 @@ int QTzTimeZonePrivate::daylightTimeOffset(qint64 atMSecsSinceEpoch) const
bool QTzTimeZonePrivate::hasDaylightTime() const
{
// TODO Perhaps cache as frequently accessed?
for (const QTzTransitionRule &rule : cached_data.m_tranRules) {
if (rule.dstOffset != 0)
return true;
}
return false;
return cached_data.m_hasDst;
}
bool QTzTimeZonePrivate::isDaylightTime(qint64 atMSecsSinceEpoch) const

1
tests/auto/corelib/time/qtimezone/tst_qtimezone.cpp
View File

@ -1140,6 +1140,7 @@ void tst_QTimeZone::tzTest()
// Test POSIX-format value for $TZ:
QTzTimeZonePrivate tzposix("MET-1METDST-2,M3.5.0/02:00:00,M10.5.0/03:00:00");
QVERIFY(tzposix.isValid());
QVERIFY(tzposix.hasDaylightTime());
// RHEL has been seen with this as Africa/Casablanca's POSIX rule:
QTzTimeZonePrivate permaDst("<+00>0<+01>,0/0,J365/25");