diff options
| -rw-r--r-- | src/corelib/tools/qstring.h | 10 | ||||
| -rw-r--r-- | src/corelib/tools/qstringview.cpp | 533 | ||||
| -rw-r--r-- | src/corelib/tools/qstringview.h | 226 | ||||
| -rw-r--r-- | src/corelib/tools/tools.pri | 2 | ||||
| -rw-r--r-- | tests/auto/corelib/tools/qstringview/.gitignore | 1 | ||||
| -rw-r--r-- | tests/auto/corelib/tools/qstringview/qstringview.pro | 6 | ||||
| -rw-r--r-- | tests/auto/corelib/tools/qstringview/tst_qstringview.cpp | 446 | ||||
| -rw-r--r-- | tests/auto/corelib/tools/tools.pro | 1 |
8 files changed, 1225 insertions, 0 deletions
diff --git a/src/corelib/tools/qstring.h b/src/corelib/tools/qstring.h index 8a7f4ff324..2b7118e960 100644 --- a/src/corelib/tools/qstring.h +++ b/src/corelib/tools/qstring.h @@ -73,6 +73,10 @@ Q_FORWARD_DECLARE_CF_TYPE(CFString); Q_FORWARD_DECLARE_OBJC_CLASS(NSString); #endif +#ifndef QT_STRINGVIEW_LEVEL +# define QT_STRINGVIEW_LEVEL 1 +#endif + QT_BEGIN_NAMESPACE class QCharRef; @@ -83,6 +87,7 @@ class QString; class QStringList; class QTextCodec; class QStringRef; +class QStringView; template <typename T> class QVector; class QLatin1String @@ -875,6 +880,7 @@ private: friend class QCharRef; friend class QTextCodec; friend class QStringRef; + friend class QStringView; friend class QByteArray; friend class QCollator; friend struct QAbstractConcatenable; @@ -1574,6 +1580,10 @@ inline QStringRef::QStringRef(const QString *aString, int aPosition, int aSize) inline QStringRef::QStringRef(const QString *aString) :m_string(aString), m_position(0), m_size(aString?aString->size() : 0){} +QT_BEGIN_INCLUDE_NAMESPACE +#include <QtCore/qstringview.h> +QT_END_INCLUDE_NAMESPACE + // QStringRef <> QStringRef Q_CORE_EXPORT bool operator==(const QStringRef &s1, const QStringRef &s2) Q_DECL_NOTHROW; inline bool operator!=(const QStringRef &s1, const QStringRef &s2) Q_DECL_NOTHROW diff --git a/src/corelib/tools/qstringview.cpp b/src/corelib/tools/qstringview.cpp new file mode 100644 index 0000000000..8504b941b3 --- /dev/null +++ b/src/corelib/tools/qstringview.cpp @@ -0,0 +1,533 @@ +/**************************************************************************** +** +** Copyright (C) 2017 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Marc Mutz <marc.mutz@kdab.com> +** Contact: http://www.qt.io/licensing/ +** +** This file is part of the QtCore module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and The Qt Company. For licensing terms +** and conditions see https://www.qt.io/terms-conditions. For further +** information use the contact form at https://www.qt.io/contact-us. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 3 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL3 included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 3 requirements +** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 2.0 or (at your option) the GNU General +** Public license version 3 or any later version approved by the KDE Free +** Qt Foundation. The licenses are as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 +** included in the packaging of this file. Please review the following +** information to ensure the GNU General Public License requirements will +** be met: https://www.gnu.org/licenses/gpl-2.0.html and +** https://www.gnu.org/licenses/gpl-3.0.html. +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qstringview.h" + +QT_BEGIN_NAMESPACE + +/*! + \class QStringView + \inmodule QtCore + \since 5.10 + \brief The QStringView class provides a unified view on UTF-16 strings + \reentrant + \ingroup tools + \ingroup string-processing + + QStringView provides a read-only subset of the QString API. + + A string view explicitly stores a portion of a UTF-16 string it does + not own. It acts as an interface type to all kinds of UTF-16 string, + without the need to construct a QString first. + + The UTF-16 string may be represented as an array (or an array-compatible + data-structure such as QString, + std::basic_string, etc.) of \c QChar, \c ushort, \c char16_t (on compilers that + support C++11 Unicode strings) or (on platforms, such as Windows, + where it is a 16-bit type) \c wchar_t. + + QStringView is designed as an interface type; its main use-case is + as a function parameter type. When QStringViews are used as automatic + variables or data members, care must be taken to ensure that the referenced + string data (for example, owned by a QString) outlives the QStringView on all code paths, + lest the string view ends up referencing deleted data. + + When used as an interface type, QStringView allows a single function to accept + a wide variety of UTF-16 string data sources. One function accepting QStringView + thus replaces three function overloads (taking QString, QStringRef, and + \c{(const QChar*, int)}), while at the same time enabling even more string data + sources to be passed to the function, such as \c{u"Hello World"}, a \c char16_t + string literal. + + QStringViews should be passed by value, not by reference-to-const: + \code + void myfun1(QStringView sv); // preferred + void myfun2(const QStringView &sv); // compiles and works, but slower + \endcode + + If you want to give your users maximum freedom in what strings they can pass + to your function, accompany the QStringView overload with overloads for + + \list + \li \e QChar: this overload can delegate to the QStringView version: + \code + void fun(QChar ch) { fun(QStringView(&ch, 1)); } + \endcode + even though, for technical reasons, QStringView cannot provide a + QChar constructor by itself. + \li \e QString: if you store an unmodified copy of the string and thus would + like to take advantage of QString's implicit sharing. + \li QLatin1String: if you can implement the function without converting the + QLatin1String to UTF-16 first; users expect a function overloaded on + QLatin1String to perform strictly less memory allocations than the + semantically equivalent call of the QStringView version, involving + construction of a QString from the QLatin1String. + \endlist + + QStringView can also be used as the return value of a function. If you call a + function returning QStringView, take extra care to not keep the QStringView + around longer than the function promises to keep the referenced string data alive. + If in doubt, obtain a strong reference to the data by calling toString() to convert + the QStringView into a QString. + + QStringView is a \e{Literal Type}. + + \note We strongly discourage the use of QList<QStringView>, + because QList is a very inefficient container for QStringViews (it would heap-allocate + every element). Use QVector (or std::vector) to hold QStringViews instead. + + \sa QString, QStringRef +*/ + +/*! + \typedef QStringView::value_type + + Alias for \c{const QChar}. Provided for compatibility with the STL. +*/ + +/*! + \typedef QStringView::difference_type + + Alias for \c{std::ptrdiff_t}. Provided for compatibility with the STL. +*/ + +/*! + \typedef QStringView::size_type + + Alias for \c{std::ptrdiff_t}. Provided for compatibility with the STL. + + Unlike other Qt classes, QStringView uses \c ptrdiff_t as its \c size_type, to allow + accepting data from \c{std::basic_string} without truncation. The Qt API functions, + for example length(), return \c int, while the STL-compatible functions, for example + size(), return \c size_type. +*/ + +/*! + \typedef QStringView::reference + + Alias for \c{value_type &}. Provided for compatibility with the STL. + + QStringView does not support mutable references, so this is the same + as const_reference. +*/ + +/*! + \typedef QStringView::const_reference + + Alias for \c{value_type &}. Provided for compatibility with the STL. +*/ + +/*! + \typedef QStringView::pointer + + Alias for \c{value_type *}. Provided for compatibility with the STL. + + QStringView does not support mutable pointers, so this is the same + as const_pointer. +*/ + +/*! + \typedef QStringView::const_pointer + + Alias for \c{value_type *}. Provided for compatibility with the STL. +*/ + +/*! + \typedef QStringView::iterator + + This typedef provides an STL-style const iterator for QStringView. + + QStringView does not support mutable iterators, so this is the same + as const_iterator. + + \sa const_iterator, reverse_iterator +*/ + +/*! + \typedef QStringView::const_iterator + + This typedef provides an STL-style const iterator for QStringView. + + \sa iterator, const_reverse_iterator +*/ + +/*! + \typedef QStringView::reverse_iterator + + This typedef provides an STL-style const reverse iterator for QStringView. + + QStringView does not support mutable reverse iterators, so this is the + same as const_reverse_iterator. + + \sa const_reverse_iterator, iterator +*/ + +/*! + \typedef QStringView::const_reverse_iterator + + This typedef provides an STL-style const reverse iterator for QStringView. + + \sa reverse_iterator, const_iterator +*/ + +/*! + \fn QStringView::QStringView() + + Constructs a null string view. + + \sa isNull() +*/ + +/*! + \fn QStringView::QStringView(std::nullptr_t) + + Constructs a null string view. + + \sa isNull() +*/ + +/*! + \fn QStringView::QStringView(QString::Null) + \internal + + Constructs a null string view. + + \sa isNull() +*/ + +/*! + \fn QStringView::QStringView(const Char *str, size_type len) + + Constructs a string view on \a str with length \a len. + + The range \c{[str,len)} must remain valid for the lifetime of this string view object. + + Passing \c nullptr as \a str is safe if \a len is 0, too, and results in a null string view. + + The behavior is undefined if \a len is negative or, when positive, if \a str is \c nullptr. + + This constructor only participates in overload resolution if \c Char is a compatible + character type. The compatible character types are: \c QChar, \c ushort, \c char16_t and + (on platforms, such as Windows, where it is a 16-bit type) \c wchar_t. +*/ + +/*! + \fn QStringView::QStringView(const Char *str) + + Constructs a string view on \a str. The length is determined + by scanning for the first \c{char16_t(0)}. + + \a str must remain valid for the lifetime of this string view object. + + Passing \c nullptr as \a str is safe and results in a null string view. + + This constructor only participates in overload resolution if \c Char is a compatible + character type. The compatible character types are: \c QChar, \c ushort, \c char16_t and + (on platforms, such as Windows, where it is a 16-bit type) \c wchar_t. +*/ + +/*! + \fn QStringView::QStringView(const QString &str) + + Constructs a string view on \a str. + + \c{str.data()} must remain valid for the lifetime of this string view object. + + The string view will be null if and only if \c{str.isNull()}. +*/ + +/*! + \fn QStringView::QStringView(const QStringRef &str) + + Constructs a string view on \a str. + + \c{str.data()} must remain valid for the lifetime of this string view object. + + The string view will be null if and only if \c{str.isNull()}. +*/ + +/*! + \fn QStringView::QStringView(const StdBasicString &str) + + Constructs a string view on \a str. The length is taken from \c{str.size()}. + + \c{str.data()} must remain valid for the lifetime of this string view object. + + This constructor only participates in overload resolution if \c StdBasicString is an + instantiation of \c std::basic_string with a compatible character type. The + compatible character types are: \c QChar, \c ushort, \c char16_t and + (on platforms, such as Windows, where it is a 16-bit type) \c wchar_t. + + The string view will be empty if and only if \c{str.empty()}. It is unspecified + whether this constructor can result in a null string view (\c{str.data()} would + have to return \c nullptr for this). + + \sa isNull(), isEmpty() +*/ + +/*! + \fn QString QStringView::toString() const + + Returns a deep copy of this string view's data as a QString. + + The return value will be the null QString if and only if this string view is null. + + \warning QStringView can store strings with more than 2\sup{30} characters + while QString cannot. Calling this function on a string view for which size() + returns a value greater than \c{INT_MAX / 2} constitutes undefined behavior. +*/ + +/*! + \fn const QChar *QStringView::data() const + + Returns a const pointer to the first character in the string. + + \sa begin(), end() +*/ + +/*! + \fn QStringView::const_iterator QStringView::begin() const + + Returns a const \l{STL-style iterators}{STL-style iterator} pointing to the first character in + the string. + + This function is provided for STL compatibility. + + \sa end(), cbegin(), rbegin(), data() +*/ + +/*! + \fn QStringView::const_iterator QStringView::cbegin() const + + Same as begin(). + + This function is provided for STL compatibility. + + \sa cend(), begin(), crbegin(), data() +*/ + +/*! + \fn QStringView::const_iterator QStringView::end() const + + Returns a const \l{STL-style iterators}{STL-style iterator} pointing to the imaginary + character after the last character in the list. + + This function is provided for STL compatibility. + + \sa begin(), cend(), rend() +*/ + +/*! \fn QStringView::const_iterator QStringView::cend() const + + Same as end(). + + This function is provided for STL compatibility. + + \sa cbegin(), end(), crend() +*/ + +/*! + \fn QStringView::const_reverse_iterator QStringView::rbegin() const + + Returns a const \l{STL-style iterators}{STL-style} reverse iterator pointing to the first + character in the string, in reverse order. + + This function is provided for STL compatibility. + + \sa rend(), crbegin(), begin() +*/ + +/*! + \fn QStringView::const_reverse_iterator QStringView::crbegin() const + + Same as rbegin(). + + This function is provided for STL compatibility. + + \sa crend(), rbegin(), cbegin() +*/ + +/*! + \fn QStringView::const_reverse_iterator QStringView::rend() const + + Returns a \l{STL-style iterators}{STL-style} reverse iterator pointing to one past + the last character in the string, in reverse order. + + This function is provided for STL compatibility. + + \sa rbegin(), crend(), end() +*/ + +/*! + \fn QStringView::const_reverse_iterator QStringView::crend() const + + Same as rend(). + + This function is provided for STL compatibility. + + \sa crbegin(), rend(), cend() +*/ + +/*! + \fn bool QStringView::empty() const + + Returns whether this string view is empty - that is, whether \c{size() == 0}. + + This function is provided for STL compatibility. + + \sa isEmpty(), isNull(), size(), length() +*/ + +/*! + \fn bool QStringView::isEmpty() const + + Returns whether this string view is empty - that is, whether \c{size() == 0}. + + This function is provided for compatibility with other Qt containers. + + \sa empty(), isNull(), size(), length() +*/ + +/*! + \fn bool QStringView::isNull() const + + Returns whether this string view is null - that is, whether \c{data() == nullptr}. + + This functions is provided for compatibility with other Qt containers. + + \sa empty(), isEmpty(), size(), length() +*/ + +/*! + \fn QStringView::size_type QStringView::size() const + + Returns the size of this string view, in UTF-16 code points (that is, + surrogate pairs count as two for the purposes of this function, the same + as in QString and QStringRef). + + \sa empty(), isEmpty(), isNull(), length() +*/ + +/*! + \fn int QStringView::length() const + + Same as size(), except returns the result as an \c int. + + This function is provided for compatibility with other Qt containers. + + \warning QStringView can represent strings with more than 2\sup{31} characters. + Calling this function on a string view for which size() returns a value greater + than \c{INT_MAX} constitutes undefined behavior. + + \sa empty(), isEmpty(), isNull(), size() +*/ + +/*! + \fn QChar QStringView::operator[](size_type n) const + + Returns the character at position \a n in this string view. + + The behavior is undefined if \a n is negative or not less than size(). + + \sa at(), front(), back() +*/ + +/*! + \fn QChar QStringView::at(size_type n) const + + Returns the character at position \a n in this string view. + + The behavior is undefined if \a n is negative or not less than size(). + + \sa operator[](), front(), back() +*/ + +/*! + \fn QChar QStringView::front() const + + Returns the first character in the string. Same as first(). + + This function is provided for STL compatibility. + + \warning Calling this function on an empty string view constitutes + undefined behavior. + + \sa back(), first(), last() +*/ + +/*! + \fn QChar QStringView::back() const + + Returns the last character in the string. Same as last(). + + This function is provided for STL compatibility. + + \warning Calling this function on an empty string view constitutes + undefined behavior. + + \sa front(), first(), last() +*/ + +/*! + \fn QChar QStringView::first() const + + Returns the first character in the string. Same as front(). + + This function is provided for compatibility with other Qt containers. + + \warning Calling this function on an empty string view constitutes + undefined behavior. + + \sa front(), back(), last() +*/ + +/*! + \fn QChar QStringView::last() const + + Returns the last character in the string. Same as back(). + + This function is provided for compatibility with other Qt containers. + + \warning Calling this function on an empty string view constitutes + undefined behavior. + + \sa back(), front(), first() +*/ + +QT_END_NAMESPACE diff --git a/src/corelib/tools/qstringview.h b/src/corelib/tools/qstringview.h new file mode 100644 index 0000000000..5384e73039 --- /dev/null +++ b/src/corelib/tools/qstringview.h @@ -0,0 +1,226 @@ +/**************************************************************************** +** +** Copyright (C) 2017 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Marc Mutz <marc.mutz@kdab.com> +** Contact: http://www.qt.io/licensing/ +** +** This file is part of the QtCore module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and The Qt Company. For licensing terms +** and conditions see https://www.qt.io/terms-conditions. For further +** information use the contact form at https://www.qt.io/contact-us. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 3 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL3 included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 3 requirements +** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 2.0 or (at your option) the GNU General +** Public license version 3 or any later version approved by the KDE Free +** Qt Foundation. The licenses are as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 +** included in the packaging of this file. Please review the following +** information to ensure the GNU General Public License requirements will +** be met: https://www.gnu.org/licenses/gpl-2.0.html and +** https://www.gnu.org/licenses/gpl-3.0.html. +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#ifndef QSTRING_H +# include <QtCore/qstring.h> +#endif + +#ifndef QSTRINGVIEW_H +#define QSTRINGVIEW_H + +#include <string> + +QT_BEGIN_NAMESPACE + +#ifndef QT_NO_UNICODE_LITERAL +# ifndef QT_UNICODE_LITERAL +# error "If you change QStringLiteral, please change QStringViewLiteral, too" +# endif +# define QStringViewLiteral(str) QStringView(QT_UNICODE_LITERAL(str), sizeof(str) - 1) +#endif + +namespace QtPrivate { +template <typename Char> +struct IsCompatibleCharTypeHelper + : std::integral_constant<bool, + std::is_same<Char, QChar>::value || + std::is_same<Char, ushort>::value || +#if !defined(Q_OS_WIN) || defined(Q_COMPILER_UNICODE_STRINGS) + std::is_same<Char, char16_t>::value || +#endif + (std::is_same<Char, wchar_t>::value && sizeof(wchar_t) == sizeof(QChar))> {}; +template <typename Char> +struct IsCompatibleCharType + : IsCompatibleCharTypeHelper<typename std::remove_cv<typename std::remove_reference<Char>::type>::type> {}; + +template <typename T> +struct IsCompatibleStdBasicStringHelper : std::false_type {}; +template <typename Char, typename...Args> +struct IsCompatibleStdBasicStringHelper<std::basic_string<Char, Args...> > + : IsCompatibleCharType<Char> {}; + +template <typename T> +struct IsCompatibleStdBasicString + : IsCompatibleStdBasicStringHelper< + typename std::remove_cv<typename std::remove_reference<T>::type>::type + > {}; + +} // namespace QtPrivate + +class QStringView +{ +#if defined(Q_OS_WIN) && !defined(Q_COMPILER_UNICODE_STRINGS) + typedef wchar_t storage_type; +#else + typedef char16_t storage_type; +#endif +public: + typedef const QChar value_type; + typedef std::ptrdiff_t difference_type; + typedef QIntegerForSizeof<size_t>::Signed size_type; + typedef value_type &reference; + typedef value_type &const_reference; + typedef value_type *pointer; + typedef value_type *const_pointer; + + typedef pointer iterator; + typedef const_pointer const_iterator; + typedef std::reverse_iterator<iterator> reverse_iterator; + typedef std::reverse_iterator<const_iterator> const_reverse_iterator; + +private: + template <typename Char> + using if_compatible_char = typename std::enable_if<QtPrivate::IsCompatibleCharType<Char>::value, bool>::type; + + template <typename T> + using if_compatible_string = typename std::enable_if<QtPrivate::IsCompatibleStdBasicString<T>::value, bool>::type; + + template <typename Char> + static Q_DECL_RELAXED_CONSTEXPR size_type lengthHelper(const Char *str) Q_DECL_NOTHROW + { + size_type result = 0; + while (*str++) + ++result; + return result; + } + static Q_DECL_RELAXED_CONSTEXPR size_type lengthHelper(const QChar *str) Q_DECL_NOTHROW + { + size_type result = 0; + while (!str++->isNull()) + ++result; + return result; + } + + template <typename Char> + static const storage_type *castHelper(const Char *str) Q_DECL_NOTHROW + { return reinterpret_cast<const storage_type*>(str); } + static Q_DECL_CONSTEXPR const storage_type *castHelper(const storage_type *str) Q_DECL_NOTHROW + { return str; } + + // prevent + // T t; QStringView sv(t), T \in {QChar, QLatin1String, QByteArray, const char*} + // from compiling as QStringView sv(QString(t)): + QStringView(QChar) = delete; + QStringView(QLatin1String) = delete; + QStringView(const QByteArray &) = delete; + QStringView(const char *) = delete; + +#ifdef Q_OS_WIN + // prevent QStringView(Char), Char compatible, from compiling due to: + // https://connect.microsoft.com/VisualStudio/feedback/details/2256407/c-two-user-defined-conversions-incorrectly-accepted-in-implicit-conversion-sequence + template <typename Char, if_compatible_char<Char> = true> + QStringView(Char) = delete; +#endif +public: + Q_DECL_CONSTEXPR QStringView() Q_DECL_NOTHROW + : m_size(0), m_data(nullptr) {} + Q_DECL_CONSTEXPR QStringView(std::nullptr_t) Q_DECL_NOTHROW + : QStringView() {} +#if QT_DEPRECATED_SINCE(5, 9) + Q_DECL_CONSTEXPR QStringView(QString::Null) Q_DECL_NOTHROW + : QStringView() {} +#endif + + template <typename Char, if_compatible_char<Char> = true> + Q_DECL_CONSTEXPR QStringView(const Char *str, size_type len) + : m_size((Q_ASSERT(len >= 0), Q_ASSERT(str || !len), len)), + m_data(castHelper(str)) {} + + template <typename Char, if_compatible_char<Char> = true> + Q_DECL_CONSTEXPR QStringView(const Char *str) + : QStringView(str, str ? lengthHelper(str) : 0) {} + + QStringView(const QString &str) Q_DECL_NOTHROW + : QStringView(str.isNull() ? nullptr : str.data(), size_type(str.size())) {} + QStringView(const QStringRef &str) Q_DECL_NOTHROW + : QStringView(str.isNull() ? nullptr : str.data(), size_type(str.size())) {} + + template <typename StdBasicString, if_compatible_string<StdBasicString> = true> + QStringView(const StdBasicString &str) Q_DECL_NOTHROW + : QStringView(str.data(), size_type(str.size())) {} + + QString toString() const { return Q_ASSERT(size() == length()), QString(data(), length()); } + + Q_DECL_CONSTEXPR size_type size() const Q_DECL_NOTHROW { return m_size; } + const_pointer data() const Q_DECL_NOTHROW { return reinterpret_cast<const_pointer>(m_data); } + Q_DECL_CONSTEXPR const storage_type *utf16() const Q_DECL_NOTHROW { return m_data; } + + Q_DECL_CONSTEXPR QChar operator[](size_type n) const + { return Q_ASSERT(n >= 0), Q_ASSERT(n < size()), QChar(m_data[n]); } + + // + // QString API + // + + Q_DECL_CONSTEXPR QChar at(size_type n) const { return (*this)[n]; } + + // + // STL compatibility API: + // + const_iterator begin() const Q_DECL_NOTHROW { return data(); } + const_iterator end() const Q_DECL_NOTHROW { return data() + size(); } + const_iterator cbegin() const Q_DECL_NOTHROW { return begin(); } + const_iterator cend() const Q_DECL_NOTHROW { return end(); } + const_reverse_iterator rbegin() const Q_DECL_NOTHROW { return const_reverse_iterator(end()); } + const_reverse_iterator rend() const Q_DECL_NOTHROW { return const_reverse_iterator(begin()); } + const_reverse_iterator crbegin() const Q_DECL_NOTHROW { return rbegin(); } + const_reverse_iterator crend() const Q_DECL_NOTHROW { return rend(); } + + Q_DECL_CONSTEXPR bool empty() const Q_DECL_NOTHROW { return size() == 0; } + Q_DECL_CONSTEXPR QChar front() const { return Q_ASSERT(!empty()), QChar(m_data[0]); } + Q_DECL_CONSTEXPR QChar back() const { return Q_ASSERT(!empty()), QChar(m_data[m_size - 1]); } + + // + // Qt compatibility API: + // + Q_DECL_CONSTEXPR bool isNull() const Q_DECL_NOTHROW { return !m_data; } + Q_DECL_CONSTEXPR bool isEmpty() const Q_DECL_NOTHROW { return empty(); } + Q_DECL_CONSTEXPR int length() const /* not nothrow! */ + { return Q_ASSERT(int(size()) == size()), int(size()); } + Q_DECL_CONSTEXPR QChar first() const { return front(); } + Q_DECL_CONSTEXPR QChar last() const { return back(); } +private: + size_type m_size; + const storage_type *m_data; +}; +Q_DECLARE_TYPEINFO(QStringView, Q_MOVABLE_TYPE); + +QT_END_NAMESPACE + +#endif /* QSTRINGVIEW_H */ diff --git a/src/corelib/tools/tools.pri b/src/corelib/tools/tools.pri index bb6c135a1a..8dd3550617 100644 --- a/src/corelib/tools/tools.pri +++ b/src/corelib/tools/tools.pri @@ -62,6 +62,7 @@ HEADERS += \ tools/qstringiterator_p.h \ tools/qstringlist.h \ tools/qstringmatcher.h \ + tools/qstringview.h \ tools/qtextboundaryfinder.h \ tools/qtimeline.h \ tools/qtools_p.h \ @@ -106,6 +107,7 @@ SOURCES += \ tools/qstring.cpp \ tools/qstringbuilder.cpp \ tools/qstringlist.cpp \ + tools/qstringview.cpp \ tools/qtextboundaryfinder.cpp \ tools/qtimeline.cpp \ tools/qunicodetools.cpp \ diff --git a/tests/auto/corelib/tools/qstringview/.gitignore b/tests/auto/corelib/tools/qstringview/.gitignore new file mode 100644 index 0000000000..5f757d448a --- /dev/null +++ b/tests/auto/corelib/tools/qstringview/.gitignore @@ -0,0 +1 @@ +tst_qstringview diff --git a/tests/auto/corelib/tools/qstringview/qstringview.pro b/tests/auto/corelib/tools/qstringview/qstringview.pro new file mode 100644 index 0000000000..e0e9973c91 --- /dev/null +++ b/tests/auto/corelib/tools/qstringview/qstringview.pro @@ -0,0 +1,6 @@ +CONFIG += testcase +TARGET = tst_qstringview +QT = core testlib +contains(QT_CONFIG, c++14):CONFIG *= c++14 +contains(QT_CONFIG, c++1z):CONFIG *= c++1z +SOURCES += tst_qstringview.cpp diff --git a/tests/auto/corelib/tools/qstringview/tst_qstringview.cpp b/tests/auto/corelib/tools/qstringview/tst_qstringview.cpp new file mode 100644 index 0000000000..2e671040dc --- /dev/null +++ b/tests/auto/corelib/tools/qstringview/tst_qstringview.cpp @@ -0,0 +1,446 @@ +/**************************************************************************** +** +** Copyright (C) 2017 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Marc Mutz <marc.mutz@kdab.com> +** Contact: http://www.qt.io/licensing/ +** +** This file is part of the QtCore module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL21$ +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and The Qt Company. For licensing terms +** and conditions see http://www.qt.io/terms-conditions. For further +** information use the contact form at http://www.qt.io/contact-us. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 or version 3 as published by the Free +** Software Foundation and appearing in the file LICENSE.LGPLv21 and +** LICENSE.LGPLv3 included in the packaging of this file. Please review the +** following information to ensure the GNU Lesser General Public License +** requirements will be met: https://www.gnu.org/licenses/lgpl.html and +** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** As a special exception, The Qt Company gives you certain additional +** rights. These rights are described in The Qt Company LGPL Exception +** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include <QStringView> +#include <QString> +#include <QChar> +#include <QStringRef> + +#include <QTest> + +#include <string> + +template <typename T> +using CanConvert = std::is_convertible<T, QStringView>; + +// +// QChar +// + +Q_STATIC_ASSERT(CanConvert< QString >::value); +Q_STATIC_ASSERT(CanConvert<const QString >::value); +Q_STATIC_ASSERT(CanConvert< QString&>::value); +Q_STATIC_ASSERT(CanConvert<const QString&>::value); + +Q_STATIC_ASSERT(CanConvert< QStringRef >::value); +Q_STATIC_ASSERT(CanConvert<const QStringRef >::value); +Q_STATIC_ASSERT(CanConvert< QStringRef&>::value); +Q_STATIC_ASSERT(CanConvert<const QStringRef&>::value); + + +// +// ushort +// + +Q_STATIC_ASSERT(CanConvert< ushort*>::value); +Q_STATIC_ASSERT(CanConvert<const ushort*>::value); + + +// +// char16_t +// + +#if !defined(Q_OS_WIN) || defined(Q_COMPILER_UNICODE_STRINGS) + +Q_STATIC_ASSERT(CanConvert< char16_t*>::value); +Q_STATIC_ASSERT(CanConvert<const char16_t*>::value); + +#endif + +#ifdef Q_COMPILER_UNICODE_STRINGS + +Q_STATIC_ASSERT(CanConvert< std::u16string >::value); +Q_STATIC_ASSERT(CanConvert<const std::u16string >::value); +Q_STATIC_ASSERT(CanConvert< std::u16string&>::value); +Q_STATIC_ASSERT(CanConvert<const std::u16string&>::value); + +#endif + + +// +// wchar_t +// + +Q_CONSTEXPR bool CanConvertFromWCharT = +#ifdef Q_OS_WIN + true +#else + false +#endif + ; + +Q_STATIC_ASSERT(CanConvert< wchar_t*>::value == CanConvertFromWCharT); +Q_STATIC_ASSERT(CanConvert<const wchar_t*>::value == CanConvertFromWCharT); + +Q_STATIC_ASSERT(CanConvert< std::wstring >::value == CanConvertFromWCharT); +Q_STATIC_ASSERT(CanConvert<const std::wstring >::value == CanConvertFromWCharT); +Q_STATIC_ASSERT(CanConvert< std::wstring&>::value == CanConvertFromWCharT); +Q_STATIC_ASSERT(CanConvert<const std::wstring&>::value == CanConvertFromWCharT); + + +class tst_QStringView : public QObject +{ + Q_OBJECT + +private Q_SLOTS: + void constExpr() const; + void basics() const; + void at() const; + + void fromQString() const; + void fromQStringRef() const; + + void fromQCharStar() const + { + const QChar str[] = { 'H', 'e', 'l', 'l', 'o', ',', ' ', 'W', 'o', 'r', 'l', 'd', '!', 0 }; + fromLiteral(str); + } + + void fromUShortStar() const + { + const ushort str[] = { 'H', 'e', 'l', 'l', 'o', ',', ' ', 'W', 'o', 'r', 'l', 'd', '!', 0 }; + fromLiteral(str); + } + + void fromChar16TStar() const + { +#if !defined(Q_OS_WIN) || defined(Q_COMPILER_UNICODE_STRINGS) + fromLiteral(u"Hello, World!"); +#else + QSKIP("This test requires C++11 char16_t support enabled in the compiler"); +#endif + } + + void fromWCharTStar() const + { +#ifdef Q_OS_WIN + fromLiteral(L"Hello, World!"); +#else + QSKIP("This is a Windows-only test"); +#endif + } + + // std::basic_string + void fromStdStringWCharT() const + { +#ifdef Q_OS_WIN + fromStdString<wchar_t>(); +#else + QSKIP("This is a Windows-only test"); +#endif + } + void fromStdStringChar16T() const + { +#ifdef Q_COMPILER_UNICODE_STRINGS + fromStdString<char16_t>(); +#else + QSKIP("This test requires C++11 char16_t support enabled in compiler & stdlib"); +#endif + } + +private: + template <typename String> + void conversion_tests(String arg) const; + template <typename Char> + void fromLiteral(const Char *arg) const; + template <typename Char, typename Container> + void fromContainer() const; + template <typename Char> + void fromStdString() const { fromContainer<Char, std::basic_string<Char> >(); } +}; + +void tst_QStringView::constExpr() const +{ + // compile-time checks +#ifdef Q_COMPILER_CONSTEXPR + { + constexpr QStringView sv; + Q_STATIC_ASSERT(sv.size() == 0); + Q_STATIC_ASSERT(sv.isNull()); + Q_STATIC_ASSERT(sv.empty()); + Q_STATIC_ASSERT(sv.isEmpty()); + Q_STATIC_ASSERT(sv.utf16() == nullptr); + } + { + constexpr QStringView sv = QStringViewLiteral(""); + Q_STATIC_ASSERT(sv.size() == 0); + Q_STATIC_ASSERT(!sv.isNull()); + Q_STATIC_ASSERT(sv.empty()); + Q_STATIC_ASSERT(sv.isEmpty()); + Q_STATIC_ASSERT(sv.utf16() != nullptr); + } + { + constexpr QStringView sv = QStringViewLiteral("Hello"); + Q_STATIC_ASSERT(sv.size() == 5); + Q_STATIC_ASSERT(!sv.empty()); + Q_STATIC_ASSERT(!sv.isEmpty()); + Q_STATIC_ASSERT(!sv.isNull()); + Q_STATIC_ASSERT(*sv.utf16() == 'H'); + Q_STATIC_ASSERT(sv[0] == QLatin1Char('H')); + Q_STATIC_ASSERT(sv.at(0) == QLatin1Char('H')); + Q_STATIC_ASSERT(sv.front() == QLatin1Char('H')); + Q_STATIC_ASSERT(sv.first() == QLatin1Char('H')); + Q_STATIC_ASSERT(sv[4] == QLatin1Char('o')); + Q_STATIC_ASSERT(sv.at(4) == QLatin1Char('o')); + Q_STATIC_ASSERT(sv.back() == QLatin1Char('o')); + Q_STATIC_ASSERT(sv.last() == QLatin1Char('o')); + } +#endif +} + +void tst_QStringView::basics() const +{ + QStringView sv1; + + // a default-constructed QStringView is null: + QVERIFY(sv1.isNull()); + // which implies it's empty(); + QVERIFY(sv1.isEmpty()); +} + +void tst_QStringView::at() const +{ + QString hello("Hello"); + QStringView sv(hello); + QCOMPARE(sv.at(0), QChar('H')); QCOMPARE(sv[0], QChar('H')); + QCOMPARE(sv.at(1), QChar('e')); QCOMPARE(sv[1], QChar('e')); + QCOMPARE(sv.at(2), QChar('l')); QCOMPARE(sv[2], QChar('l')); + QCOMPARE(sv.at(3), QChar('l')); QCOMPARE(sv[3], QChar('l')); + QCOMPARE(sv.at(4), QChar('o')); QCOMPARE(sv[4], QChar('o')); +} + +void tst_QStringView::fromQString() const +{ + QString null; + QString empty = ""; + + QVERIFY( QStringView(null).isNull()); + QVERIFY( QStringView(null).isEmpty()); + QVERIFY( QStringView(empty).isEmpty()); + QVERIFY(!QStringView(empty).isNull()); + + conversion_tests(QString("Hello World!")); +} + +void tst_QStringView::fromQStringRef() const +{ + QStringRef null; + QString emptyS = ""; + QStringRef empty(&emptyS); + + QVERIFY( QStringView(null).isNull()); + QVERIFY( QStringView(null).isEmpty()); + QVERIFY( QStringView(empty).isEmpty()); + QVERIFY(!QStringView(empty).isNull()); + + conversion_tests(QString("Hello World!").midRef(6)); +} + +template <typename Char> +void tst_QStringView::fromLiteral(const Char *arg) const +{ + const Char *null = nullptr; + const Char empty[] = { 0 }; + + QCOMPARE(QStringView(null).size(), QStringView::size_type(0)); + QCOMPARE(QStringView(null).data(), nullptr); + QCOMPARE(QStringView(empty).size(), QStringView::size_type(0)); + QCOMPARE(static_cast<const void*>(QStringView(empty).data()), + static_cast<const void*>(empty)); + + QVERIFY( QStringView(null).isNull()); + QVERIFY( QStringView(null).isEmpty()); + QVERIFY( QStringView(empty).isEmpty()); + QVERIFY(!QStringView(empty).isNull()); + + conversion_tests(arg); +} + +template <typename Char, typename Container> +void tst_QStringView::fromContainer() const +{ + const QString s = "Hello World!"; + + Container c; + // unspecified whether empty containers make null QStringViews + QVERIFY(QStringView(c).isEmpty()); + + QCOMPARE(sizeof(Char), sizeof(QChar)); + + const auto *data = reinterpret_cast<const Char *>(s.utf16()); + std::copy(data, data + s.size(), std::back_inserter(c)); + conversion_tests(std::move(c)); +} + +namespace help { +template <typename T> +size_t size(const T &t) { return size_t(t.size()); } +template <typename T> +size_t size(const T *t) +{ + size_t result = 0; + if (t) { + while (*t++) + ++result; + } + return result; +} +size_t size(const QChar *t) +{ + size_t result = 0; + if (t) { + while (!t++->isNull()) + ++result; + } + return result; +} + +template <typename T> +typename T::const_iterator cbegin(const T &t) { return t.cbegin(); } +template <typename T> +const T * cbegin(const T *t) { return t; } + +template <typename T> +typename T::const_iterator cend(const T &t) { return t.cend(); } +template <typename T> +const T * cend(const T *t) { return t + size(t); } + +template <typename T> +typename T::const_reverse_iterator crbegin(const T &t) { return t.crbegin(); } +template <typename T> +std::reverse_iterator<const T*> crbegin(const T *t) { return std::reverse_iterator<const T*>(cend(t)); } + +template <typename T> +typename T::const_reverse_iterator crend(const T &t) { return t.crend(); } +template <typename T> +std::reverse_iterator<const T*> crend(const T *t) { return std::reverse_iterator<const T*>(cbegin(t)); } + +} // namespace help + +template <typename String> +void tst_QStringView::conversion_tests(String string) const +{ + // copy-construct: + { + QStringView sv = string; + + QCOMPARE(help::size(sv), help::size(string)); + + // check iterators: + + QVERIFY(std::equal(help::cbegin(string), help::cend(string), + QT_MAKE_CHECKED_ARRAY_ITERATOR(sv.cbegin(), sv.size()))); + QVERIFY(std::equal(help::cbegin(string), help::cend(string), + QT_MAKE_CHECKED_ARRAY_ITERATOR(sv.begin(), sv.size()))); + QVERIFY(std::equal(help::crbegin(string), help::crend(string), + sv.crbegin())); + QVERIFY(std::equal(help::crbegin(string), help::crend(string), + sv.rbegin())); + } + + QStringView sv; + + // copy-assign: + { + sv = string; + + QCOMPARE(help::size(sv), help::size(string)); + + QVERIFY(std::equal(help::cbegin(string), help::cend(string), + QT_MAKE_CHECKED_ARRAY_ITERATOR(sv.cbegin(), sv.size()))); + QVERIFY(std::equal(help::cbegin(string), help::cend(string), + QT_MAKE_CHECKED_ARRAY_ITERATOR(sv.begin(), sv.size()))); + QVERIFY(std::equal(help::crbegin(string), help::crend(string), + sv.crbegin())); + QVERIFY(std::equal(help::crbegin(string), help::crend(string), + sv.rbegin())); + } + + // copy-construct from rvalue (QStringView never assumes ownership): + { + QStringView sv2 = std::move(string); + + QCOMPARE(help::size(sv2), help::size(string)); + + QVERIFY(std::equal(help::cbegin(string), help::cend(string), + QT_MAKE_CHECKED_ARRAY_ITERATOR(sv2.cbegin(), sv2.size()))); + QVERIFY(std::equal(help::cbegin(string), help::cend(string), + QT_MAKE_CHECKED_ARRAY_ITERATOR(sv2.begin(), sv2.size()))); + QVERIFY(std::equal(help::crbegin(string), help::crend(string), + sv2.crbegin())); + QVERIFY(std::equal(help::crbegin(string), help::crend(string), + sv2.rbegin())); + + QCOMPARE(help::size(sv2), help::size(sv)); + + QVERIFY(std::equal(help::cbegin(sv), help::cend(sv), + QT_MAKE_CHECKED_ARRAY_ITERATOR(sv2.cbegin(), sv2.size()))); + QVERIFY(std::equal(help::cbegin(sv), help::cend(sv), + QT_MAKE_CHECKED_ARRAY_ITERATOR(sv2.begin(), sv2.size()))); + QVERIFY(std::equal(help::crbegin(sv), help::crend(sv), + sv2.crbegin())); + QVERIFY(std::equal(help::crbegin(sv), help::crend(sv), + sv2.rbegin())); + } + + // copy-assign from rvalue (QStringView never assumes ownership): + { + QStringView sv2; + sv2 = std::move(string); + + QCOMPARE(help::size(sv2), help::size(string)); + + QVERIFY(std::equal(help::cbegin(string), help::cend(string), + QT_MAKE_CHECKED_ARRAY_ITERATOR(sv2.cbegin(), sv2.size()))); + QVERIFY(std::equal(help::cbegin(string), help::cend(string), + QT_MAKE_CHECKED_ARRAY_ITERATOR(sv2.begin(), sv2.size()))); + QVERIFY(std::equal(help::crbegin(string), help::crend(string), + sv2.crbegin())); + QVERIFY(std::equal(help::crbegin(string), help::crend(string), + sv2.rbegin())); + + QCOMPARE(help::size(sv2), help::size(sv)); + + QVERIFY(std::equal(help::cbegin(sv), help::cend(sv), + QT_MAKE_CHECKED_ARRAY_ITERATOR(sv2.cbegin(), sv2.size()))); + QVERIFY(std::equal(help::cbegin(sv), help::cend(sv), + QT_MAKE_CHECKED_ARRAY_ITERATOR(sv2.begin(), sv2.size()))); + QVERIFY(std::equal(help::crbegin(sv), help::crend(sv), + sv2.crbegin())); + QVERIFY(std::equal(help::crbegin(sv), help::crend(sv), + sv2.rbegin())); + } +} + +QTEST_APPLESS_MAIN(tst_QStringView) +#include "tst_qstringview.moc" diff --git a/tests/auto/corelib/tools/tools.pro b/tests/auto/corelib/tools/tools.pro index e45771a704..e16648c15f 100644 --- a/tests/auto/corelib/tools/tools.pro +++ b/tests/auto/corelib/tools/tools.pro @@ -56,6 +56,7 @@ SUBDIRS=\ qstringlist \ qstringmatcher \ qstringref \ + qstringview \ qtextboundaryfinder \ qtime \ qtimezone \ |