Improve readability of code that uses the Qt signed size typev5.10.0-rc2

During the container BoF session at the Qt Contributor Summit 2017 the
name of the signed size type became a subject of discussion in the
context of readability of code using this type and the intention of
using it for all length, size and count properties throughout the entire
framework in future versions of Qt.

This change proposes qsizetype as new name for qssize_t to emphasize the
readability of code over POSIX compatibility, the former being
potentially more relevant than the latter to the majority of users of
Qt.

Change-Id: Idb99cb4a8782703c054fa463a9e5af23a918e7f3
Reviewed-by: Samuel Gaist <samuel.gaist@edeltech.ch>
Reviewed-by: David Faure <david.faure@kdab.com>

7 files changed, 40 insertions, 40 deletions

diff --git a/src/corelib/tools/qlocale.cpp b/src/corelib/tools/qlocale.cpp
index 723e63114d..166cbe8dee 100644
--- a/src/corelib/tools/qlocale.cpp
+++ b/src/corelib/tools/qlocale.cpp
@@ -576,7 +576,7 @@ int qt_repeatCount(QStringView s)
     if (s.isEmpty())
         return 0;
     const QChar c = s.front();
-    qssize_t j = 1;
+    qsizetype j = 1;
     while (j < s.size() && s.at(j) == c)
         ++j;
     return int(j);
@@ -3443,7 +3443,7 @@ bool QLocaleData::validateChars(QStringView str, NumberMode numMode, QByteArray
     bool dec = false;
     int decDigitCnt = 0;
 
-    for (qssize_t i = 0; i < str.size(); ++i) {
+    for (qsizetype i = 0; i < str.size(); ++i) {
         char c = digitToCLocale(str.at(i));
 
         if (c >= '0' && c <= '9') {
diff --git a/src/corelib/tools/qstring.cpp b/src/corelib/tools/qstring.cpp
index c10987a5fe..bba0a85319 100644
--- a/src/corelib/tools/qstring.cpp
+++ b/src/corelib/tools/qstring.cpp
@@ -160,9 +160,9 @@ static inline bool qt_ends_with(QStringView haystack, QStringView needle, Qt::Ca
 static inline bool qt_ends_with(QStringView haystack, QLatin1String needle, Qt::CaseSensitivity cs);
 static inline bool qt_ends_with(QStringView haystack, QChar needle, Qt::CaseSensitivity cs);
 
-qssize_t QtPrivate::qustrlen(const ushort *str) Q_DECL_NOTHROW
+qsizetype QtPrivate::qustrlen(const ushort *str) Q_DECL_NOTHROW
 {
-    qssize_t result = 0;
+    qsizetype result = 0;
 
 #ifdef __SSE2__
     // find the 16-byte alignment immediately prior or equal to str
diff --git a/src/corelib/tools/qstringalgorithms.h b/src/corelib/tools/qstringalgorithms.h
index 336da87468..aaa702301e 100644
--- a/src/corelib/tools/qstringalgorithms.h
+++ b/src/corelib/tools/qstringalgorithms.h
@@ -55,7 +55,7 @@ template <typename T> class QVector;
 
 namespace QtPrivate {
 
-Q_REQUIRED_RESULT Q_CORE_EXPORT Q_DECL_PURE_FUNCTION qssize_t qustrlen(const ushort *str) Q_DECL_NOTHROW;
+Q_REQUIRED_RESULT Q_CORE_EXPORT Q_DECL_PURE_FUNCTION qsizetype qustrlen(const ushort *str) Q_DECL_NOTHROW;
 
 Q_REQUIRED_RESULT Q_CORE_EXPORT Q_DECL_PURE_FUNCTION int compareStrings(QStringView   lhs, QStringView   rhs, Qt::CaseSensitivity cs = Qt::CaseSensitive) Q_DECL_NOTHROW;
 Q_REQUIRED_RESULT Q_CORE_EXPORT Q_DECL_PURE_FUNCTION int compareStrings(QStringView   lhs, QLatin1String rhs, Qt::CaseSensitivity cs = Qt::CaseSensitive) Q_DECL_NOTHROW;
diff --git a/src/corelib/tools/qstringiterator.qdoc b/src/corelib/tools/qstringiterator.qdoc
index 95c2247bc1..caec8803f3 100644
--- a/src/corelib/tools/qstringiterator.qdoc
+++ b/src/corelib/tools/qstringiterator.qdoc
@@ -120,7 +120,7 @@
 */
 
 /*!
-    \fn QStringIterator::QStringIterator(QStringView string, qssize_t idx)
+    \fn QStringIterator::QStringIterator(QStringView string, qsizetype idx)
 
     Constructs an iterator over the contents of \a string. The iterator will point
     before position \a idx in the string.
diff --git a/src/corelib/tools/qstringiterator_p.h b/src/corelib/tools/qstringiterator_p.h
index 8b1a6a1cd3..219589b6e4 100644
--- a/src/corelib/tools/qstringiterator_p.h
+++ b/src/corelib/tools/qstringiterator_p.h
@@ -62,7 +62,7 @@ class QStringIterator
     QString::const_iterator i, pos, e;
     Q_STATIC_ASSERT((std::is_same<QString::const_iterator, const QChar *>::value));
 public:
-    explicit QStringIterator(QStringView string, qssize_t idx = 0)
+    explicit QStringIterator(QStringView string, qsizetype idx = 0)
         : i(string.begin()),
           pos(i + idx),
           e(string.end())
diff --git a/src/corelib/tools/qstringview.cpp b/src/corelib/tools/qstringview.cpp
index 8eefc6d814..bb22239b66 100644
--- a/src/corelib/tools/qstringview.cpp
+++ b/src/corelib/tools/qstringview.cpp
@@ -131,9 +131,9 @@ QT_BEGIN_NAMESPACE
 /*!
     \typedef QStringView::size_type
 
-    Alias for qssize_t. Provided for compatibility with the STL.
+    Alias for qsizetype. Provided for compatibility with the STL.
 
-    Unlike other Qt classes, QStringView uses qssize_t as its \c size_type, to allow
+    Unlike other Qt classes, QStringView uses qsizetype 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.
@@ -224,7 +224,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn QStringView::QStringView(const Char *str, qssize_t len)
+    \fn QStringView::QStringView(const Char *str, qsizetype len)
 
     Constructs a string view on \a str with length \a len.
 
@@ -486,7 +486,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn qssize_t QStringView::size() const
+    \fn qsizetype 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
@@ -510,7 +510,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn QChar QStringView::operator[](qssize_t n) const
+    \fn QChar QStringView::operator[](qsizetype n) const
 
     Returns the character at position \a n in this string view.
 
@@ -520,7 +520,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn QChar QStringView::at(qssize_t n) const
+    \fn QChar QStringView::at(qsizetype n) const
 
     Returns the character at position \a n in this string view.
 
@@ -582,7 +582,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn QStringView QStringView::mid(qssize_t start) const
+    \fn QStringView QStringView::mid(qsizetype start) const
 
     Returns the substring starting at position \a start in this object,
     and extending to the end of the string.
@@ -593,7 +593,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn QStringView QStringView::mid(qssize_t start, qssize_t length) const
+    \fn QStringView QStringView::mid(qsizetype start, qsizetype length) const
     \overload
 
     Returns the substring of length \a length starting at position
@@ -606,7 +606,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn QStringView QStringView::left(qssize_t length) const
+    \fn QStringView QStringView::left(qsizetype length) const
 
     Returns the substring of length \a length starting at position
     0 in this object.
@@ -617,7 +617,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn QStringView QStringView::right(qssize_t length) const
+    \fn QStringView QStringView::right(qsizetype length) const
 
     Returns the substring of length \a length starting at position
     size() - \a length in this object.
@@ -628,7 +628,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn QStringView QStringView::chopped(qssize_t length) const
+    \fn QStringView QStringView::chopped(qsizetype length) const
 
     Returns the substring of length size() - \a length starting at the
     beginning of this object.
@@ -641,7 +641,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn void QStringView::truncate(qssize_t length)
+    \fn void QStringView::truncate(qsizetype length)
 
     Truncates this string view to length \a length.
 
@@ -653,7 +653,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn void QStringView::chop(qssize_t length)
+    \fn void QStringView::chop(qsizetype length)
 
     Truncates this string view by \a length characters.
 
diff --git a/src/corelib/tools/qstringview.h b/src/corelib/tools/qstringview.h
index 14405f325d..903d7ccb24 100644
--- a/src/corelib/tools/qstringview.h
+++ b/src/corelib/tools/qstringview.h
@@ -111,7 +111,7 @@ public:
 #endif
     typedef const QChar value_type;
     typedef std::ptrdiff_t difference_type;
-    typedef qssize_t size_type;
+    typedef qsizetype size_type;
     typedef value_type &reference;
     typedef value_type &const_reference;
     typedef value_type *pointer;
@@ -139,24 +139,24 @@ private:
     using if_compatible_qstring_like = typename std::enable_if<std::is_same<T, QString>::value || std::is_same<T, QStringRef>::value, bool>::type;
 
     template <typename Char, size_t N>
-    static Q_DECL_CONSTEXPR qssize_t lengthHelperArray(const Char (&)[N]) Q_DECL_NOTHROW
+    static Q_DECL_CONSTEXPR qsizetype lengthHelperArray(const Char (&)[N]) Q_DECL_NOTHROW
     {
-        return qssize_t(N - 1);
+        return qsizetype(N - 1);
     }
 
     template <typename Char>
-    static qssize_t lengthHelperPointer(const Char *str) Q_DECL_NOTHROW
+    static qsizetype lengthHelperPointer(const Char *str) Q_DECL_NOTHROW
     {
 #if defined(Q_CC_GNU) && !defined(Q_CC_CLANG) && !defined(Q_CC_INTEL)
         if (__builtin_constant_p(*str)) {
-            qssize_t result = 0;
+            qsizetype result = 0;
             while (*str++)
                 ++result;
         }
 #endif
         return QtPrivate::qustrlen(reinterpret_cast<const ushort *>(str));
     }
-    static qssize_t lengthHelperPointer(const QChar *str) Q_DECL_NOTHROW
+    static qsizetype lengthHelperPointer(const QChar *str) Q_DECL_NOTHROW
     {
         return QtPrivate::qustrlen(reinterpret_cast<const ushort *>(str));
     }
@@ -174,7 +174,7 @@ public:
         : QStringView() {}
 
     template <typename Char, if_compatible_char<Char> = true>
-    Q_DECL_CONSTEXPR QStringView(const Char *str, qssize_t len)
+    Q_DECL_CONSTEXPR QStringView(const Char *str, qsizetype len)
         : m_size((Q_ASSERT(len >= 0), Q_ASSERT(str || !len), len)),
           m_data(castHelper(str)) {}
 
@@ -204,20 +204,20 @@ public:
 #else
     template <typename String, if_compatible_qstring_like<String> = true>
     QStringView(const String &str) Q_DECL_NOTHROW
-        : QStringView(str.isNull() ? nullptr : str.data(), qssize_t(str.size())) {}
+        : QStringView(str.isNull() ? nullptr : str.data(), qsizetype(str.size())) {}
 #endif
 
     template <typename StdBasicString, if_compatible_string<StdBasicString> = true>
     QStringView(const StdBasicString &str) Q_DECL_NOTHROW
-        : QStringView(str.data(), qssize_t(str.size())) {}
+        : QStringView(str.data(), qsizetype(str.size())) {}
 
     Q_REQUIRED_RESULT inline QString toString() const; // defined in qstring.h
 
-    Q_REQUIRED_RESULT Q_DECL_CONSTEXPR qssize_t size() const Q_DECL_NOTHROW { return m_size; }
+    Q_REQUIRED_RESULT Q_DECL_CONSTEXPR qsizetype size() const Q_DECL_NOTHROW { return m_size; }
     Q_REQUIRED_RESULT const_pointer data() const Q_DECL_NOTHROW { return reinterpret_cast<const_pointer>(m_data); }
     Q_REQUIRED_RESULT Q_DECL_CONSTEXPR const storage_type *utf16() const Q_DECL_NOTHROW { return m_data; }
 
-    Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QChar operator[](qssize_t n) const
+    Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QChar operator[](qsizetype n) const
     { return Q_ASSERT(n >= 0), Q_ASSERT(n < size()), QChar(m_data[n]); }
 
     //
@@ -229,22 +229,22 @@ public:
     Q_REQUIRED_RESULT QByteArray toLocal8Bit() const { return QtPrivate::convertToLocal8Bit(*this); }
     Q_REQUIRED_RESULT inline QVector<uint> toUcs4() const; // defined in qvector.h
 
-    Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QChar at(qssize_t n) const { return (*this)[n]; }
+    Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QChar at(qsizetype n) const { return (*this)[n]; }
 
-    Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QStringView mid(qssize_t pos) const
+    Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QStringView mid(qsizetype pos) const
     { return Q_ASSERT(pos >= 0), Q_ASSERT(pos <= size()), QStringView(m_data + pos, m_size - pos); }
-    Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QStringView mid(qssize_t pos, qssize_t n) const
+    Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QStringView mid(qsizetype pos, qsizetype n) const
     { return Q_ASSERT(pos >= 0), Q_ASSERT(n >= 0), Q_ASSERT(pos + n <= size()), QStringView(m_data + pos, n); }
-    Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QStringView left(qssize_t n) const
+    Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QStringView left(qsizetype n) const
     { return Q_ASSERT(n >= 0), Q_ASSERT(n <= size()), QStringView(m_data, n); }
-    Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QStringView right(qssize_t n) const
+    Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QStringView right(qsizetype n) const
     { return Q_ASSERT(n >= 0), Q_ASSERT(n <= size()), QStringView(m_data + m_size - n, n); }
-    Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QStringView chopped(qssize_t n) const
+    Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QStringView chopped(qsizetype n) const
     { return Q_ASSERT(n >= 0), Q_ASSERT(n <= size()), QStringView(m_data, m_size - n); }
 
-    Q_DECL_RELAXED_CONSTEXPR void truncate(qssize_t n)
+    Q_DECL_RELAXED_CONSTEXPR void truncate(qsizetype n)
     { Q_ASSERT(n >= 0); Q_ASSERT(n <= size()); m_size = n; }
-    Q_DECL_RELAXED_CONSTEXPR void chop(qssize_t n)
+    Q_DECL_RELAXED_CONSTEXPR void chop(qsizetype n)
     { Q_ASSERT(n >= 0); Q_ASSERT(n <= size()); m_size -= n; }
 
     Q_REQUIRED_RESULT QStringView trimmed() const Q_DECL_NOTHROW { return QtPrivate::trimmed(*this); }
@@ -291,7 +291,7 @@ public:
     Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QChar first() const { return front(); }
     Q_REQUIRED_RESULT Q_DECL_CONSTEXPR QChar last()  const { return back(); }
 private:
-    qssize_t m_size;
+    qsizetype m_size;
     const storage_type *m_data;
 };
 Q_DECLARE_TYPEINFO(QStringView, Q_PRIMITIVE_TYPE);