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QRegularExpressionMatch: add a way to know if a capturing group captured 

Relying on the fact that a given capturing group captured a null string
doesn't allow users to distinguish whether a capturing group did not
capture anything, or captured a null substring (say, from a null subject
string).

Perl allows for the distinction: the entries in the @- and @+ arrays are
set to values in case there is a capture, but they're undef otherwise.

PCRE2 gives us the information already in the results "ovector", but
it was simply not exposed to QREM users. So, expose it.

[ChangeLog][QtCore][QRegularExpressionMatch] Added the hasCaptured()
family of functions to know if a given capturing group has captured
something.

Change-Id: Ic1320933d4554e2e313c0a680be1b1b9dd95af0b
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
bb10
Giuseppe D'Angelo 2021-08-06 10:17:50 +02:00
parent 145940e1ef
commit bac329a28b
4 changed files with 245 additions and 83 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
src/corelib/doc/snippets/code/src_corelib_text_qregularexpression.cpp
View File

@ -374,4 +374,16 @@ QRegularExpression re(R"(\d\d \w+)");
//! [35]
}
{
//! [36]
QRegularExpression re("([a-z]+)|([A-Z]+)");
QRegularExpressionMatch m = re.match("UPPERCASE");
if (m.hasMatch()) {
qDebug() << m.hasCaptured(0); // true
qDebug() << m.hasCaptured(1); // false
qDebug() << m.hasCaptured(2); // true
}
//! [36]
}
}

71
src/corelib/text/qregularexpression.cpp
View File

@ -1259,6 +1259,12 @@ void QRegularExpressionPrivate::doMatch(QRegularExpressionMatchPrivate *priv,
PCRE2_SIZE *ovector = pcre2_get_ovector_pointer_16(matchData);
qsizetype *const capturedOffsets = priv->capturedOffsets.data();
// We rely on the fact that capturing groups that did not
// capture anything have offset -1, but PCRE technically
// returns "PCRE2_UNSET". Test that out, better safe than
// sorry...
static_assert(qsizetype(PCRE2_UNSET) == qsizetype(-1), "Internal error: PCRE2 changed its API");
for (int i = 0; i < priv->capturedCount * 2; ++i)
capturedOffsets[i] = qsizetype(ovector[i]);
@ -2178,13 +2184,70 @@ QRegularExpression::MatchOptions QRegularExpressionMatch::matchOptions() const
If the regular expression did not match, this function returns -1.
\sa captured(), capturedStart(), capturedEnd(), capturedLength()
\sa hasCaptured(), captured(), capturedStart(), capturedEnd(), capturedLength()
*/
int QRegularExpressionMatch::lastCapturedIndex() const
{
return d->capturedCount - 1;
}
/*!
\fn bool QRegularExpressionMatch::hasCaptured(const QString &name) const
\fn bool QRegularExpressionMatch::hasCaptured(QStringView name) const
\since 6.3
Returns true if the capturing group named \a name captured something
in the subject string, and false otherwise (or if there is no
capturing group called \a name).
\note Some capturing groups in a regular expression may not have
captured anything even if the regular expression matched. This may
happen, for instance, if a conditional operator is used in the
pattern:
\snippet code/src_corelib_text_qregularexpression.cpp 36
Similarly, a capturing group may capture a substring of length 0;
this function will return \c{true} for such a capturing group.
\sa captured(), hasMatch()
*/
bool QRegularExpressionMatch::hasCaptured(QStringView name) const
{
const int nth = d->regularExpression.d->captureIndexForName(name);
return hasCaptured(nth);
}
/*!
\since 6.3
Returns true if the \a nth capturing group captured something
in the subject string, and false otherwise (or if there is no
such capturing group).
\note The implicit capturing group number 0 captures the substring
matched by the entire pattern.
\note Some capturing groups in a regular expression may not have
captured anything even if the regular expression matched. This may
happen, for instance, if a conditional operator is used in the
pattern:
\snippet code/src_corelib_text_qregularexpression.cpp 36
Similarly, a capturing group may capture a substring of length 0;
this function will return \c{true} for such a capturing group.
\sa captured(), lastCapturedIndex(), hasMatch()
*/
bool QRegularExpressionMatch::hasCaptured(int nth) const
{
if (nth < 0 || nth > lastCapturedIndex())
return false;
return d->capturedOffsets.at(nth * 2) != -1;
}
/*!
Returns the substring captured by the \a nth capturing group.
@ -2218,7 +2281,7 @@ QString QRegularExpressionMatch::captured(int nth) const
*/
QStringView QRegularExpressionMatch::capturedView(int nth) const
{
if (nth < 0 || nth > lastCapturedIndex())
if (!hasCaptured(nth))
return QStringView();
qsizetype start = capturedStart(nth);
@ -2312,7 +2375,7 @@ QStringList QRegularExpressionMatch::capturedTexts() const
*/
qsizetype QRegularExpressionMatch::capturedStart(int nth) const
{
if (nth < 0 || nth > lastCapturedIndex())
if (!hasCaptured(nth))
return -1;
return d->capturedOffsets.at(nth * 2);
@ -2341,7 +2404,7 @@ qsizetype QRegularExpressionMatch::capturedLength(int nth) const
*/
qsizetype QRegularExpressionMatch::capturedEnd(int nth) const
{
if (nth < 0 || nth > lastCapturedIndex())
if (!hasCaptured(nth))
return -1;
return d->capturedOffsets.at(nth * 2 + 1);

7
src/corelib/text/qregularexpression.h
View File

@ -233,6 +233,13 @@ public:
int lastCapturedIndex() const;
#if QT_STRINGVIEW_LEVEL < 2
bool hasCaptured(const QString &name) const
{ return hasCaptured(QStringView(name)); }
#endif
bool hasCaptured(QStringView name) const;
bool hasCaptured(int nth) const;
QString captured(int nth = 0) const;
QStringView capturedView(int nth = 0) const;

238
tests/auto/corelib/text/qregularexpression/tst_qregularexpression.cpp
View File

@ -37,6 +37,8 @@
#include <qregularexpression.h>
#include <qthread.h>
#include <optional>
Q_DECLARE_METATYPE(QRegularExpression::PatternOptions)
Q_DECLARE_METATYPE(QRegularExpression::MatchType)
Q_DECLARE_METATYPE(QRegularExpression::MatchOptions)
@ -92,6 +94,8 @@ private:
void provideRegularExpressions();
};
using CapturedList = QVector<std::optional<QString>>;
struct Match
{
Match()
@ -111,8 +115,8 @@ struct Match
bool isValid;
bool hasMatch;
bool hasPartialMatch;
QStringList captured;
QHash<QString, QString> namedCaptured;
CapturedList captured;
QHash<QString, std::optional<QString>> namedCaptured;
};
QT_BEGIN_NAMESPACE
Q_DECLARE_TYPEINFO(Match, Q_RELOCATABLE_TYPE);
@ -129,27 +133,53 @@ bool operator==(const QRegularExpressionMatch &rem, const Match &m)
if ((rem.hasMatch() != m.hasMatch) || (rem.hasPartialMatch() != m.hasPartialMatch))
return false;
if (rem.hasMatch() || rem.hasPartialMatch()) {
if (!rem.hasCaptured(0))
return false;
if (rem.lastCapturedIndex() != (m.captured.size() - 1))
return false;
for (int i = 0; i <= rem.lastCapturedIndex(); ++i) {
auto mMaybeCaptured = m.captured.at(i);
QString remCaptured = rem.captured(i);
QString mCaptured = m.captured.at(i);
if (remCaptured != mCaptured
|| remCaptured.isNull() != mCaptured.isNull()
|| remCaptured.isEmpty() != mCaptured.isEmpty()) {
return false;
if (!mMaybeCaptured) {
if (rem.hasCaptured(i))
return false;
if (!remCaptured.isNull())
return false;
} else {
if (!rem.hasCaptured(i))
return false;
QString mCaptured = *mMaybeCaptured;
if (remCaptured != mCaptured
|| remCaptured.isNull() != mCaptured.isNull()
|| remCaptured.isEmpty() != mCaptured.isEmpty()) {
return false;
}
}
}
for (auto it = m.namedCaptured.begin(), end = m.namedCaptured.end(); it != end; ++it) {
const QString remCaptured = rem.captured(it.key());
const QString mCaptured = it.value();
if (remCaptured != mCaptured
|| remCaptured.isNull() != mCaptured.isNull()
|| remCaptured.isEmpty() != mCaptured.isEmpty()) {
return false;
const QString capturedGroupName = it.key();
const QString remCaptured = rem.captured(capturedGroupName);
const auto mMaybeCaptured = it.value();
if (!mMaybeCaptured) {
if (rem.hasCaptured(capturedGroupName))
return false;
if (!remCaptured.isNull())
return false;
} else {
if (!rem.hasCaptured(capturedGroupName))
return false;
const auto mCaptured = *mMaybeCaptured;
if (remCaptured != mCaptured
|| remCaptured.isNull() != mCaptured.isNull()
|| remCaptured.isEmpty() != mCaptured.isEmpty()) {
return false;
}
}
}
} else {
if (rem.hasCaptured(0))
return false;
}
return true;
@ -803,7 +833,7 @@ void tst_QRegularExpression::normalMatch_data()
m.clear();
m.isValid = true; m.hasMatch = true;
m.captured << " string" << QString() << "string";
m.captured << " string" << std::nullopt << "string";
QTest::newRow("match04") << QRegularExpression("(\\w+)? (\\w+)")
<< " string"
<< qsizetype(0)
@ -887,9 +917,9 @@ void tst_QRegularExpression::normalMatch_data()
m.captured << "a string" << "a" << "string";
m.namedCaptured["article"] = "a";
m.namedCaptured["noun"] = "string";
m.namedCaptured["nonexisting1"] = QString();
m.namedCaptured["nonexisting2"] = QString();
m.namedCaptured["nonexisting3"] = QString();
m.namedCaptured["nonexisting1"] = std::nullopt;
m.namedCaptured["nonexisting2"] = std::nullopt;
m.namedCaptured["nonexisting3"] = std::nullopt;
QTest::newRow("match10") << QRegularExpression("(?<article>\\w+) (?<noun>\\w+)")
<< "a string"
<< qsizetype(0)
@ -900,7 +930,7 @@ void tst_QRegularExpression::normalMatch_data()
m.isValid = true; m.hasMatch = true;
m.captured << "" << "";
m.namedCaptured["digits"] = ""; // empty VS null
m.namedCaptured["nonexisting"] = QString();
m.namedCaptured["nonexisting"] = std::nullopt;
QTest::newRow("match11") << QRegularExpression("(?<digits>\\d*)")
<< "abcde"
<< qsizetype(0)
@ -921,6 +951,56 @@ void tst_QRegularExpression::normalMatch_data()
// ***
m.clear();
m.isValid = true; m.hasMatch = true;
m.captured << QString() << QString();
QTest::newRow("capture-in-null-string")
<< QRegularExpression("(a*)")
<< QString()
<< qsizetype(0)
<< QRegularExpression::MatchOptions(QRegularExpression::NoMatchOption)
<< m;
m.clear();
m.isValid = true; m.hasMatch = true;
m.captured << QString() << QString() << QString();
QTest::newRow("capture-in-null-string-2")
<< QRegularExpression("(a*)(b*)")
<< QString()
<< qsizetype(0)
<< QRegularExpression::MatchOptions(QRegularExpression::NoMatchOption)
<< m;
m.clear();
m.isValid = true; m.hasMatch = true;
m.captured << QString();
QTest::newRow("no-capture-in-null-string")
<< QRegularExpression("(a+)?")
<< QString()
<< qsizetype(0)
<< QRegularExpression::MatchOptions(QRegularExpression::NoMatchOption)
<< m;
m.clear();
m.isValid = true; m.hasMatch = true;
m.captured << "bb" << QString("") << "bb";
QTest::newRow("empty-capture-in-non-null-string")
<< QRegularExpression("(a*)(b*)")
<< QString("bbc")
<< qsizetype(0)
<< QRegularExpression::MatchOptions(QRegularExpression::NoMatchOption)
<< m;
m.clear();
m.isValid = true; m.hasMatch = true;
m.captured << "bb" << std::nullopt << "bb";
QTest::newRow("no-capture-in-non-null-string")
<< QRegularExpression("(a+)?(b+)?")
<< QString("bbc")
<< qsizetype(0)
<< QRegularExpression::MatchOptions(QRegularExpression::NoMatchOption)
<< m;
m.clear();
m.isValid = true;
QTest::newRow("nomatch01") << QRegularExpression("\\d+")
@ -1316,11 +1396,11 @@ void tst_QRegularExpression::globalMatch_data()
matchList.clear();
m.clear();
m.isValid = true; m.hasMatch = true;
m.captured = QStringList() << "the";
m.captured = CapturedList() << "the";
matchList << m;
m.captured = QStringList() << "quick";
m.captured = CapturedList() << "quick";
matchList << m;
m.captured = QStringList() << "fox";
m.captured = CapturedList() << "fox";
matchList << m;
QTest::newRow("globalmatch01") << QRegularExpression("\\w+")
<< "the quick fox"
@ -1332,11 +1412,11 @@ void tst_QRegularExpression::globalMatch_data()
matchList.clear();
m.clear();
m.isValid = true; m.hasMatch = true;
m.captured = QStringList() << "the" << "t" << "he";
m.captured = CapturedList() << "the" << "t" << "he";
matchList << m;
m.captured = QStringList() << "quick" << "q" << "uick";
m.captured = CapturedList() << "quick" << "q" << "uick";
matchList << m;
m.captured = QStringList() << "fox" << "f" << "ox";
m.captured = CapturedList() << "fox" << "f" << "ox";
matchList << m;
QTest::newRow("globalmatch02") << QRegularExpression("(\\w+?)(\\w+)")
<< "the quick fox"
@ -1348,13 +1428,13 @@ void tst_QRegularExpression::globalMatch_data()
matchList.clear();
m.clear();
m.isValid = true; m.hasMatch = true;
m.captured = QStringList() << "ACA""GTG""CGA""AAA";
m.captured = CapturedList() << "ACA""GTG""CGA""AAA";
matchList << m;
m.captured = QStringList() << "AAA";
m.captured = CapturedList() << "AAA";
matchList << m;
m.captured = QStringList() << "AAG""GAA""AAG""AAA";
m.captured = CapturedList() << "AAG""GAA""AAG""AAA";
matchList << m;
m.captured = QStringList() << "AAA";
m.captured = CapturedList() << "AAA";
matchList << m;
QTest::newRow("globalmatch03") << QRegularExpression("\\G(?:\\w\\w\\w)*?AAA")
<< "ACA""GTG""CGA""AAA""AAA""AAG""GAA""AAG""AAA""AAA"
@ -1373,19 +1453,19 @@ void tst_QRegularExpression::globalMatch_data()
matchList.clear();
m.clear();
m.isValid = true; m.hasMatch = true;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << "c";
m.captured = CapturedList() << "c";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << "c";
m.captured = CapturedList() << "c";
matchList << m;
m.captured = QStringList() << "aabb";
m.captured = CapturedList() << "aabb";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
QTest::newRow("globalmatch_emptycaptures01") << QRegularExpression("a*b*|c")
@ -1398,17 +1478,17 @@ void tst_QRegularExpression::globalMatch_data()
matchList.clear();
m.clear();
m.isValid = true; m.hasMatch = true;
m.captured = QStringList() << "the";
m.captured = CapturedList() << "the";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << "quick";
m.captured = CapturedList() << "quick";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << "fox";
m.captured = CapturedList() << "fox";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
QTest::newRow("globalmatch_emptycaptures02") << QRegularExpression(".*")
@ -1421,19 +1501,19 @@ void tst_QRegularExpression::globalMatch_data()
matchList.clear();
m.clear();
m.isValid = true; m.hasMatch = true;
m.captured = QStringList() << "the";
m.captured = CapturedList() << "the";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << "quick";
m.captured = CapturedList() << "quick";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << "fox";
m.captured = CapturedList() << "fox";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
QTest::newRow("globalmatch_emptycaptures03") << QRegularExpression(".*")
@ -1446,17 +1526,17 @@ void tst_QRegularExpression::globalMatch_data()
matchList.clear();
m.clear();
m.isValid = true; m.hasMatch = true;
m.captured = QStringList() << "the";
m.captured = CapturedList() << "the";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << "quick";
m.captured = CapturedList() << "quick";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << "fox";
m.captured = CapturedList() << "fox";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
QTest::newRow("globalmatch_emptycaptures04") << QRegularExpression("(*CRLF).*")
@ -1469,19 +1549,19 @@ void tst_QRegularExpression::globalMatch_data()
matchList.clear();
m.clear();
m.isValid = true; m.hasMatch = true;
m.captured = QStringList() << "the";
m.captured = CapturedList() << "the";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << "quick";
m.captured = CapturedList() << "quick";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << "fox";
m.captured = CapturedList() << "fox";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
QTest::newRow("globalmatch_emptycaptures05") << QRegularExpression("(*CRLF).*")
@ -1494,21 +1574,21 @@ void tst_QRegularExpression::globalMatch_data()
matchList.clear();
m.clear();
m.isValid = true; m.hasMatch = true;
m.captured = QStringList() << "the";
m.captured = CapturedList() << "the";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << "quick";
m.captured = CapturedList() << "quick";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << "fox";
m.captured = CapturedList() << "fox";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << "jumped";
m.captured = CapturedList() << "jumped";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
QTest::newRow("globalmatch_emptycaptures06") << QRegularExpression("(*ANYCRLF).*")
@ -1521,17 +1601,17 @@ void tst_QRegularExpression::globalMatch_data()
matchList.clear();
m.clear();
m.isValid = true; m.hasMatch = true;
m.captured = QStringList() << "ABC";
m.captured = CapturedList() << "ABC";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << "DEF";
m.captured = CapturedList() << "DEF";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << "GHI";
m.captured = CapturedList() << "GHI";
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
QTest::newRow("globalmatch_emptycaptures07") << QRegularExpression("[\\x{0000}-\\x{FFFF}]*")
<< QString::fromUtf8("ABC""\xf0\x9d\x85\x9d""DEF""\xf0\x9d\x85\x9e""GHI")
@ -1543,13 +1623,13 @@ void tst_QRegularExpression::globalMatch_data()
matchList.clear();
m.clear();
m.isValid = true; m.hasMatch = true;
m.captured = QStringList() << QString::fromUtf8("ABC""\xc3\x80");
m.captured = CapturedList() << QString::fromUtf8("ABC""\xc3\x80");
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
m.captured = QStringList() << QString::fromUtf8("\xc3\x80""DEF""\xc3\x80");
m.captured = CapturedList() << QString::fromUtf8("\xc3\x80""DEF""\xc3\x80");
matchList << m;
m.captured = QStringList() << "";
m.captured = CapturedList() << "";
matchList << m;
QTest::newRow("globalmatch_emptycaptures08") << QRegularExpression("[\\x{0000}-\\x{FFFF}]*")
<< QString::fromUtf8("ABC""\xc3\x80""\xf0\x9d\x85\x9d""\xc3\x80""DEF""\xc3\x80")