JSON: add some QStringView overloads

[ChangeLog][QtCore][JSON] Added overloads of functions taking key
strings as QStringView; in QJsonObject, QJsonValue and QJsonDocument.

Change-Id: I78b40aba8200003acfae257ff06f5f15737005e7
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Anton Kudryavtsev <antkudr@mail.ru>

8 files changed, 180 insertions, 37 deletions

diff --git a/src/corelib/serialization/qjson.cpp b/src/corelib/serialization/qjson.cpp
index d74ffb2a20..76f1eae1ce 100644
--- a/src/corelib/serialization/qjson.cpp
+++ b/src/corelib/serialization/qjson.cpp
@@ -175,7 +175,7 @@ void Base::removeItems(int pos, int numItems)
     length -= numItems;
 }
 
-int Object::indexOf(const QString &key, bool *exists) const
+int Object::indexOf(QStringView key, bool *exists) const
 {
     int min = 0;
     int n = length;
@@ -257,7 +257,7 @@ bool Array::isValid(int maxSize) const
 }
 
 
-bool Entry::operator ==(const QString &key) const
+bool Entry::operator ==(QStringView key) const
 {
     if (value.latinKey)
         return (shallowLatin1Key() == key);
@@ -270,7 +270,7 @@ bool Entry::operator==(QLatin1String key) const
     if (value.latinKey)
         return shallowLatin1Key() == key;
     else
-        return shallowKey() == key;
+        return shallowKey() == QString(key); // ### conversion to QString
 }
 
 bool Entry::operator ==(const Entry &other) const
diff --git a/src/corelib/serialization/qjson_p.h b/src/corelib/serialization/qjson_p.h
index 9de53d5b74..78082a920d 100644
--- a/src/corelib/serialization/qjson_p.h
+++ b/src/corelib/serialization/qjson_p.h
@@ -153,14 +153,14 @@ typedef qle_uint offset;
 // round the size up to the next 4 byte boundary
 inline int alignedSize(int size) { return (size + 3) & ~3; }
 
-static inline bool useCompressed(const QString &s)
+static inline bool useCompressed(QStringView s)
 {
     if (s.length() >= 0x8000)
         return false;
     return QtPrivate::isLatin1(s);
 }
 
-static inline int qStringSize(const QString &string, bool compress)
+static inline int qStringSize(QStringView string, bool compress)
 {
     int l = 2 + string.length();
     if (!compress)
@@ -214,37 +214,31 @@ public:
         return maxSize >= 0 && uint(d->length) <= maxSize / sizeof(ushort);
     }
 
-    inline String &operator=(const QString &str)
+    inline String &operator=(QStringView str)
     {
         d->length = str.length();
-#if Q_BYTE_ORDER == Q_BIG_ENDIAN
-        const ushort *uc = (const ushort *)str.unicode();
-        for (int i = 0; i < str.length(); ++i)
-            d->utf16[i] = uc[i];
-#else
-        memcpy(d->utf16, str.unicode(), str.length()*sizeof(ushort));
-#endif
+        qToLittleEndian<quint16>(str.utf16(), str.length(), d->utf16);
         if (str.length() & 1)
             d->utf16[str.length()] = 0;
         return *this;
     }
 
-    inline bool operator ==(const QString &str) const {
+    inline bool operator ==(QStringView str) const {
         int slen = str.length();
         int l = d->length;
         if (slen != l)
             return false;
-        const ushort *s = (const ushort *)str.constData();
+        const ushort *s = (const ushort *)str.utf16();
         const qle_ushort *a = d->utf16;
         const ushort *b = s;
         while (l-- && *a == *b)
             a++,b++;
         return (l == -1);
     }
-    inline bool operator !=(const QString &str) const {
+    inline bool operator !=(QStringView str) const {
         return !operator ==(str);
     }
-    inline bool operator >=(const QString &str) const {
+    inline bool operator >=(QStringView str) const {
         // ###
         return toString() >= str;
     }
@@ -292,11 +286,11 @@ public:
         return byteSize() <= maxSize;
     }
 
-    inline Latin1String &operator=(const QString &str)
+    inline Latin1String &operator=(QStringView str)
     {
         int len = d->length = str.length();
         uchar *l = (uchar *)d->latin1;
-        const ushort *uc = (const ushort *)str.unicode();
+        const ushort *uc = (const ushort *)str.utf16();
         qt_to_latin1_unchecked(l, uc, len);
 
         for ( ; (quintptr)(l+len) & 0x3; ++len)
@@ -351,11 +345,11 @@ public:
     { \
         return lhs.toQLatin1String() op rhs; \
     } \
-    inline bool operator op(const QString &lhs, Latin1String rhs) noexcept \
+    inline bool operator op(QStringView lhs, Latin1String rhs) noexcept \
     { \
         return lhs op rhs.toQLatin1String(); \
     } \
-    inline bool operator op(Latin1String lhs, const QString &rhs) noexcept \
+    inline bool operator op(Latin1String lhs, QStringView rhs) noexcept \
     { \
         return lhs.toQLatin1String() op rhs; \
     } \
@@ -419,7 +413,7 @@ inline bool String::operator<(const Latin1String &str) const
 
 }
 
-static inline void copyString(char *dest, const QString &str, bool compress)
+static inline void copyString(char *dest, QStringView str, bool compress)
 {
     if (compress) {
         Latin1String string(dest);
@@ -469,7 +463,7 @@ public:
     Entry *entryAt(int i) const {
         return reinterpret_cast<Entry *>(((char *)this) + table()[i]);
     }
-    int indexOf(const QString &key, bool *exists) const;
+    int indexOf(QStringView key, bool *exists) const;
     int indexOf(QLatin1String key, bool *exists) const;
 
     bool isValid(int maxSize) const;
@@ -577,9 +571,9 @@ public:
         return shallowKey().isValid(maxSize);
     }
 
-    bool operator ==(const QString &key) const;
-    inline bool operator !=(const QString &key) const { return !operator ==(key); }
-    inline bool operator >=(const QString &key) const;
+    bool operator ==(QStringView key) const;
+    inline bool operator !=(QStringView key) const { return !operator ==(key); }
+    inline bool operator >=(QStringView key) const;
 
     bool operator==(QLatin1String key) const;
     inline bool operator!=(QLatin1String key) const { return !operator ==(key); }
@@ -589,7 +583,7 @@ public:
     bool operator >=(const Entry &other) const;
 };
 
-inline bool Entry::operator >=(const QString &key) const
+inline bool Entry::operator >=(QStringView key) const
 {
     if (value.latinKey)
         return (shallowLatin1Key() >= key);
@@ -602,10 +596,10 @@ inline bool Entry::operator >=(QLatin1String key) const
     if (value.latinKey)
         return shallowLatin1Key() >= key;
     else
-        return shallowKey() >= key;
+        return shallowKey() >= QString(key); // ### conversion to QString
 }
 
-inline bool operator <(const QString &key, const Entry &e)
+inline bool operator <(QStringView key, const Entry &e)
 { return e >= key; }
 
 inline bool operator<(QLatin1String key, const Entry &e)
diff --git a/src/corelib/serialization/qjsondocument.cpp b/src/corelib/serialization/qjsondocument.cpp
index f8027efb58..193b80ee22 100644
--- a/src/corelib/serialization/qjsondocument.cpp
+++ b/src/corelib/serialization/qjsondocument.cpp
@@ -544,6 +544,7 @@ void QJsonDocument::setArray(const QJsonArray &array)
     d->ref.ref();
 }
 
+#if QT_STRINGVIEW_LEVEL < 2
 /*!
     Returns a QJsonValue representing the value for the key \a key.
 
@@ -558,6 +559,16 @@ void QJsonDocument::setArray(const QJsonArray &array)
  */
 const QJsonValue QJsonDocument::operator[](const QString &key) const
 {
+    return (*this)[QStringView(key)];
+}
+#endif
+
+/*!
+    \overload
+    \since 5.14
+*/
+const QJsonValue QJsonDocument::operator[](QStringView key) const
+{
     if (!isObject())
         return QJsonValue(QJsonValue::Undefined);
 
diff --git a/src/corelib/serialization/qjsondocument.h b/src/corelib/serialization/qjsondocument.h
index a8006a6cc5..a8e7485f5d 100644
--- a/src/corelib/serialization/qjsondocument.h
+++ b/src/corelib/serialization/qjsondocument.h
@@ -146,7 +146,10 @@ public:
     void setObject(const QJsonObject &object);
     void setArray(const QJsonArray &array);
 
+#if QT_STRINGVIEW_LEVEL < 2
     const QJsonValue operator[](const QString &key) const;
+#endif
+    const QJsonValue operator[](QStringView key) const;
     const QJsonValue operator[](QLatin1String key) const;
     const QJsonValue operator[](int i) const;
 
diff --git a/src/corelib/serialization/qjsonobject.cpp b/src/corelib/serialization/qjsonobject.cpp
index e800d76ab6..19a16d8537 100644
--- a/src/corelib/serialization/qjsonobject.cpp
+++ b/src/corelib/serialization/qjsonobject.cpp
@@ -377,6 +377,7 @@ bool QJsonObject::isEmpty() const
     return !o->length;
 }
 
+#if QT_STRINGVIEW_LEVEL < 2
 /*!
     Returns a QJsonValue representing the value for the key \a key.
 
@@ -386,6 +387,16 @@ bool QJsonObject::isEmpty() const
  */
 QJsonValue QJsonObject::value(const QString &key) const
 {
+    return value(QStringView(key));
+}
+#endif
+
+/*!
+    \overload
+    \since 5.14
+*/
+QJsonValue QJsonObject::value(QStringView key) const
+{
     if (!d)
         return QJsonValue(QJsonValue::Undefined);
 
@@ -412,6 +423,7 @@ QJsonValue QJsonObject::value(QLatin1String key) const
     return QJsonValue(d, o, o->entryAt(i)->value);
 }
 
+#if QT_STRINGVIEW_LEVEL < 2
 /*!
     Returns a QJsonValue representing the value for the key \a key.
 
@@ -423,8 +435,16 @@ QJsonValue QJsonObject::value(QLatin1String key) const
  */
 QJsonValue QJsonObject::operator [](const QString &key) const
 {
-    return value(key);
+    return (*this)[QStringView(key)];
 }
+#endif
+
+/*!
+    \fn QJsonValue QJsonObject::operator [](QStringView key) const
+
+    \overload
+    \since 5.14
+*/
 
 /*!
     \fn QJsonValue QJsonObject::operator [](QLatin1String key) const
@@ -433,6 +453,7 @@ QJsonValue QJsonObject::operator [](const QString &key) const
     \since 5.7
 */
 
+#if QT_STRINGVIEW_LEVEL < 2
 /*!
     Returns a reference to the value for \a key.
 
@@ -446,6 +467,16 @@ QJsonValue QJsonObject::operator [](const QString &key) const
  */
 QJsonValueRef QJsonObject::operator [](const QString &key)
 {
+    return (*this)[QStringView(key)];
+}
+#endif
+
+/*!
+    \overload
+    \since 5.14
+*/
+QJsonValueRef QJsonObject::operator [](QStringView key)
+{
     bool keyExists = false;
     int index = o ? o->indexOf(key, &keyExists) : 0;
     if (!keyExists) {
@@ -465,6 +496,7 @@ QJsonValueRef QJsonObject::operator [](QLatin1String key)
     return operator[](QString(key));
 }
 
+#if QT_STRINGVIEW_LEVEL < 2
 /*!
     Inserts a new item with the key \a key and a value of \a value.
 
@@ -480,6 +512,16 @@ QJsonValueRef QJsonObject::operator [](QLatin1String key)
  */
 QJsonObject::iterator QJsonObject::insert(const QString &key, const QJsonValue &value)
 {
+    return insert(QStringView(key), value);
+}
+#endif
+
+/*!
+    \overload
+    \since 5.14
+*/
+QJsonObject::iterator QJsonObject::insert(QStringView key, const QJsonValue &value)
+{
     if (value.t == QJsonValue::Undefined) {
         remove(key);
         return end();
@@ -492,7 +534,7 @@ QJsonObject::iterator QJsonObject::insert(const QString &key, const QJsonValue &
 /*!
     \internal
  */
-QJsonObject::iterator QJsonObject::insertAt(int pos, const QString &key, const QJsonValue &value, bool keyExists)
+QJsonObject::iterator QJsonObject::insertAt(int pos, QStringView key, const QJsonValue &value, bool keyExists)
 {
     QJsonValue val = value;
 
@@ -530,6 +572,7 @@ QJsonObject::iterator QJsonObject::insertAt(int pos, const QString &key, const Q
     return iterator(this, pos);
 }
 
+#if QT_STRINGVIEW_LEVEL < 2
 /*!
     Removes \a key from the object.
 
@@ -537,6 +580,16 @@ QJsonObject::iterator QJsonObject::insertAt(int pos, const QString &key, const Q
  */
 void QJsonObject::remove(const QString &key)
 {
+    remove(QStringView(key));
+}
+#endif
+
+/*!
+    \overload
+    \since 5.14
+*/
+void QJsonObject::remove(QStringView key)
+{
     if (!d)
         return;
 
@@ -548,6 +601,7 @@ void QJsonObject::remove(const QString &key)
     removeAt(index);
 }
 
+#if QT_STRINGVIEW_LEVEL < 2
 /*!
     Removes \a key from the object.
 
@@ -559,6 +613,16 @@ void QJsonObject::remove(const QString &key)
  */
 QJsonValue QJsonObject::take(const QString &key)
 {
+    return take(QStringView(key));
+}
+#endif
+
+/*!
+    \overload
+    \since 5.14
+*/
+QJsonValue QJsonObject::take(QStringView key)
+{
     if (!o)
         return QJsonValue(QJsonValue::Undefined);
 
@@ -573,6 +637,7 @@ QJsonValue QJsonObject::take(const QString &key)
     return v;
 }
 
+#if QT_STRINGVIEW_LEVEL < 2
 /*!
     Returns \c true if the object contains key \a key.
 
@@ -580,6 +645,16 @@ QJsonValue QJsonObject::take(const QString &key)
  */
 bool QJsonObject::contains(const QString &key) const
 {
+    return contains(QStringView(key));
+}
+#endif
+
+/*!
+    \overload
+    \since 5.14
+*/
+bool QJsonObject::contains(QStringView key) const
+{
     if (!o)
         return false;
 
@@ -656,6 +731,7 @@ QJsonObject::iterator QJsonObject::erase(QJsonObject::iterator it)
     return it;
 }
 
+#if QT_STRINGVIEW_LEVEL < 2
 /*!
     Returns an iterator pointing to the item with key \a key in the
     map.
@@ -665,6 +741,16 @@ QJsonObject::iterator QJsonObject::erase(QJsonObject::iterator it)
  */
 QJsonObject::iterator QJsonObject::find(const QString &key)
 {
+    return find(QStringView(key));
+}
+#endif
+
+/*!
+    \overload
+    \since 5.14
+*/
+QJsonObject::iterator QJsonObject::find(QStringView key)
+{
     bool keyExists = false;
     int index = o ? o->indexOf(key, &keyExists) : 0;
     if (!keyExists)
@@ -687,10 +773,18 @@ QJsonObject::iterator QJsonObject::find(QLatin1String key)
     return iterator(this, index);
 }
 
+#if QT_STRINGVIEW_LEVEL < 2
 /*! \fn QJsonObject::const_iterator QJsonObject::find(const QString &key) const
 
     \overload
 */
+#endif
+
+/*! \fn QJsonObject::const_iterator QJsonObject::find(QStringView key) const
+
+    \overload
+    \since 5.14
+*/
 
 /*! \fn QJsonObject::const_iterator QJsonObject::find(QLatin1String key) const
 
@@ -698,6 +792,7 @@ QJsonObject::iterator QJsonObject::find(QLatin1String key)
     \since 5.7
 */
 
+#if QT_STRINGVIEW_LEVEL < 2
 /*!
     Returns a const iterator pointing to the item with key \a key in the
     map.
@@ -707,6 +802,16 @@ QJsonObject::iterator QJsonObject::find(QLatin1String key)
  */
 QJsonObject::const_iterator QJsonObject::constFind(const QString &key) const
 {
+    return constFind(QStringView(key));
+}
+#endif
+
+/*!
+    \overload
+    \since 5.14
+*/
+QJsonObject::const_iterator QJsonObject::constFind(QStringView key) const
+{
     bool keyExists = false;
     int index = o ? o->indexOf(key, &keyExists) : 0;
     if (!keyExists)
diff --git a/src/corelib/serialization/qjsonobject.h b/src/corelib/serialization/qjsonobject.h
index b12769d3d3..bdaf85b460 100644
--- a/src/corelib/serialization/qjsonobject.h
+++ b/src/corelib/serialization/qjsonobject.h
@@ -100,16 +100,26 @@ public:
     inline int length() const { return size(); }
     bool isEmpty() const;
 
+#if QT_STRINGVIEW_LEVEL < 2
     QJsonValue value(const QString &key) const;
-    QJsonValue value(QLatin1String key) const;
     QJsonValue operator[] (const QString &key) const;
-    QJsonValue operator[] (QLatin1String key) const { return value(key); }
     QJsonValueRef operator[] (const QString &key);
+#endif
+    QJsonValue value(QStringView key) const;
+    QJsonValue value(QLatin1String key) const;
+    QJsonValue operator[] (QStringView key) const { return value(key); }
+    QJsonValue operator[] (QLatin1String key) const { return value(key); }
+    QJsonValueRef operator[] (QStringView key);
     QJsonValueRef operator[] (QLatin1String key);
 
+#if QT_STRINGVIEW_LEVEL < 2
     void remove(const QString &key);
     QJsonValue take(const QString &key);
     bool contains(const QString &key) const;
+#endif
+    void remove(QStringView key);
+    QJsonValue take(QStringView key);
+    bool contains(QStringView key) const;
     bool contains(QLatin1String key) const;
 
     bool operator==(const QJsonObject &other) const;
@@ -218,13 +228,19 @@ public:
     // more Qt
     typedef iterator Iterator;
     typedef const_iterator ConstIterator;
+#if QT_STRINGVIEW_LEVEL < 2
     iterator find(const QString &key);
-    iterator find(QLatin1String key);
     const_iterator find(const QString &key) const { return constFind(key); }
-    const_iterator find(QLatin1String key) const { return constFind(key); }
     const_iterator constFind(const QString &key) const;
-    const_iterator constFind(QLatin1String key) const;
     iterator insert(const QString &key, const QJsonValue &value);
+#endif
+    iterator find(QStringView key);
+    iterator find(QLatin1String key);
+    const_iterator find(QStringView key) const { return constFind(key); }
+    const_iterator find(QLatin1String key) const { return constFind(key); }
+    const_iterator constFind(QStringView key) const;
+    const_iterator constFind(QLatin1String key) const;
+    iterator insert(QStringView key, const QJsonValue &value);
 
     // STL compatibility
     typedef QJsonValue mapped_type;
@@ -253,7 +269,7 @@ private:
     QJsonValue valueAt(int i) const;
     void setValueAt(int i, const QJsonValue &val);
     void removeAt(int i);
-    iterator insertAt(int i, const QString &key, const QJsonValue &val, bool exists);
+    iterator insertAt(int i, QStringView key, const QJsonValue &val, bool exists);
 
     QJsonPrivate::Data *d;
     QJsonPrivate::Object *o;
diff --git a/src/corelib/serialization/qjsonvalue.cpp b/src/corelib/serialization/qjsonvalue.cpp
index 0bd28581f3..5f07a6a03e 100644
--- a/src/corelib/serialization/qjsonvalue.cpp
+++ b/src/corelib/serialization/qjsonvalue.cpp
@@ -694,6 +694,7 @@ QJsonObject QJsonValue::toObject() const
     return toObject(QJsonObject());
 }
 
+#if QT_STRINGVIEW_LEVEL < 2
 /*!
     Returns a QJsonValue representing the value for the key \a key.
 
@@ -708,6 +709,16 @@ QJsonObject QJsonValue::toObject() const
  */
 const QJsonValue QJsonValue::operator[](const QString &key) const
 {
+    return (*this)[QStringView(key)];
+}
+#endif
+
+/*!
+    \overload
+    \since 5.14
+*/
+const QJsonValue QJsonValue::operator[](QStringView key) const
+{
     if (!isObject())
         return QJsonValue(QJsonValue::Undefined);
 
diff --git a/src/corelib/serialization/qjsonvalue.h b/src/corelib/serialization/qjsonvalue.h
index 37d84f9e60..430fa06c0f 100644
--- a/src/corelib/serialization/qjsonvalue.h
+++ b/src/corelib/serialization/qjsonvalue.h
@@ -137,7 +137,10 @@ public:
     QJsonObject toObject() const;
     QJsonObject toObject(const QJsonObject &defaultValue) const;
 
+#if QT_STRINGVIEW_LEVEL < 2
     const QJsonValue operator[](const QString &key) const;
+#endif
+    const QJsonValue operator[](QStringView key) const;
     const QJsonValue operator[](QLatin1String key) const;
     const QJsonValue operator[](int i) const;