QTextCodec: add QStringView overloads

[ChangeLog][QtCore][QTextCodec] Added fromUnicode()
and canEncode() overloads taking QStringView.
[ChangeLog][QtCore][QTextEncoder] Added fromUnicode()
overload taking QStringView.

Change-Id: I2599f25570480d967921ccd4414e092bfc90d821
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

src/corelib/codecs/qtextcodec.cpp

@@ -803,6 +803,7 @@ QTextEncoder* QTextCodec::makeEncoder(QTextCodec::ConversionFlags flags) const
     The \a state of the convertor used is updated.
 */
 
+#if QT_STRINGVIEW_LEVEL < 2
 /*!
     Converts \a str from Unicode to the encoding of this codec, and
     returns the result in a QByteArray.
@@ -811,6 +812,19 @@ QByteArray QTextCodec::fromUnicode(const QString& str) const
 {
     return convertFromUnicode(str.constData(), str.length(), 0);
 }
+#endif
+
+/*!
+    \overload
+    \since 5.10
+
+    Converts \a str from Unicode to the encoding of this codec, and
+    returns the result in a QByteArray.
+*/
+QByteArray QTextCodec::fromUnicode(QStringView str) const
+{
+    return convertFromUnicode(str.data(), str.length(), nullptr);
+}
 
 /*!
     \fn QString QTextCodec::toUnicode(const char *input, int size,
@@ -844,6 +858,7 @@ bool QTextCodec::canEncode(QChar ch) const
     return (state.invalidChars == 0);
 }
 
+#if QT_STRINGVIEW_LEVEL < 2
 /*!
     \overload
 
@@ -856,7 +871,22 @@ bool QTextCodec::canEncode(const QString& s) const
     convertFromUnicode(s.constData(), s.length(), &state);
     return (state.invalidChars == 0);
 }
+#endif
 
+/*!
+    \overload
+    \since 5.10
+
+    Returns \c true if the Unicode string \a s can be fully encoded
+    with this codec; otherwise returns \c false.
+*/
+bool QTextCodec::canEncode(QStringView s) const
+{
+    ConverterState state;
+    state.flags = ConvertInvalidToNull;
+    convertFromUnicode(s.data(), s.length(), &state);
+    return !state.invalidChars;
+}
 /*!
     \overload
 
@@ -921,6 +951,7 @@ bool QTextEncoder::hasFailure() const
     return state.invalidChars != 0;
 }
 
+#if QT_STRINGVIEW_LEVEL < 2
 /*!
     Converts the Unicode string \a str into an encoded QByteArray.
 */
@@ -929,6 +960,17 @@ QByteArray QTextEncoder::fromUnicode(const QString& str)
     QByteArray result = c->fromUnicode(str.constData(), str.length(), &state);
     return result;
 }
+#endif
+
+/*!
+    \overload
+    \since 5.10
+    Converts the Unicode string \a str into an encoded QByteArray.
+*/
+QByteArray QTextEncoder::fromUnicode(QStringView str)
+{
+    return c->fromUnicode(str.data(), str.length(), &state);
+}
 
 /*!
     \overload

src/corelib/codecs/qtextcodec.h

@@ -79,11 +79,17 @@ public:
     static QTextCodec *codecForUtfText(const QByteArray &ba, QTextCodec *defaultCodec);
 
     bool canEncode(QChar) const;
+#if QT_STRINGVIEW_LEVEL < 2
     bool canEncode(const QString&) const;
+#endif
+    bool canEncode(QStringView) const;
 
     QString toUnicode(const QByteArray&) const;
     QString toUnicode(const char* chars) const;
+#if QT_STRINGVIEW_LEVEL < 2
     QByteArray fromUnicode(const QString& uc) const;
+#endif
+    QByteArray fromUnicode(QStringView uc) const;
     enum ConversionFlag {
         DefaultConversion,
         ConvertInvalidToNull = 0x80000000,
@@ -135,7 +141,10 @@ public:
     explicit QTextEncoder(const QTextCodec *codec) : c(codec), state() {}
     QTextEncoder(const QTextCodec *codec, QTextCodec::ConversionFlags flags);
     ~QTextEncoder();
+#if QT_STRINGVIEW_LEVEL < 2
     QByteArray fromUnicode(const QString& str);
+#endif
+    QByteArray fromUnicode(QStringView str);
     QByteArray fromUnicode(const QChar *uc, int len);
     bool hasFailure() const;
 private:

tests/auto/corelib/codecs/qtextcodec/tst_qtextcodec.cpp

@@ -126,6 +126,7 @@ void tst_QTextCodec::toUnicode()
         }
         QVERIFY(!uniString.isEmpty());
         QCOMPARE( ba, c->fromUnicode( uniString ) );
+        QCOMPARE(ba, c->fromUnicode(QStringView(uniString)) );
 
         char ch = '\0';
         QVERIFY(c->toUnicode(&ch, 1).length() == 1);
@@ -262,7 +263,7 @@ void tst_QTextCodec::fromUnicode()
         If the encoding is a superset of ASCII, test that the byte
         array is correct (no off by one, no trailing '\0').
     */
-    QByteArray result = codec->fromUnicode(QString("abc"));
+    QByteArray result = codec->fromUnicode(QStringViewLiteral("abc"));
     if (result.startsWith('a')) {
         QCOMPARE(result.size(), 3);
         QCOMPARE(result, QByteArray("abc"));
@@ -397,6 +398,7 @@ void tst_QTextCodec::asciiToIscii() const
 
         QVERIFY2(textCodec->canEncode(ascii), qPrintable(QString::fromLatin1("Failed for full string with encoding %1")
                                                          .arg(QString::fromLatin1(textCodec->name().constData()))));
+        QVERIFY(textCodec->canEncode(QStringView(ascii)));
     }
 }
 
@@ -404,12 +406,11 @@ void tst_QTextCodec::nonFlaggedCodepointFFFF() const
 {
     //Check that the code point 0xFFFF (=non-character code 0xEFBFBF) is not flagged
     const QChar ch(0xFFFF);
-    QString input(ch);
 
     QTextCodec *const codec = QTextCodec::codecForMib(106); // UTF-8
     QVERIFY(codec);
 
-    const QByteArray asDecoded(codec->fromUnicode(input));
+    const QByteArray asDecoded = codec->fromUnicode(QStringView(&ch, 1));
     QCOMPARE(asDecoded, QByteArray("\357\277\277"));
 
     QByteArray ffff("\357\277\277");