QStringConverter/Encoder/Decoder: make move noexcept

The State state data member had non-noexcept move-SMFs, which were
inherited by the move-SMFs of QStringConverter, QStringEncoder and
QStringDecoder.

To fix, because it is called in the move-assignment operator, we need
to mark State::clear() as noexcept, and, since that can perform an
indirect call through clearFn, require the clearFn to be noexcept,
too.

The only users of clearFn were in Qt5Compat; a separate fix should
have been merged there by the time this lands.

Change-Id: Ibe8147970886526b6a479960050e108607b63874
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

2 files changed, 10 insertions, 5 deletions

diff --git a/src/corelib/text/qstringconverter.cpp b/src/corelib/text/qstringconverter.cpp
index e6c2552348..199e85aaae 100644
--- a/src/corelib/text/qstringconverter.cpp
+++ b/src/corelib/text/qstringconverter.cpp
@@ -60,6 +60,11 @@
 
 QT_BEGIN_NAMESPACE
 
+static_assert(std::is_nothrow_move_constructible_v<QStringEncoder>);
+static_assert(std::is_nothrow_move_assignable_v<QStringEncoder>);
+static_assert(std::is_nothrow_move_constructible_v<QStringDecoder>);
+static_assert(std::is_nothrow_move_assignable_v<QStringDecoder>);
+
 enum { Endian = 0, Data = 1 };
 
 static const uchar utf8bom[] = { 0xef, 0xbb, 0xbf };
@@ -1388,7 +1393,7 @@ QByteArray QLocal8Bit::convertFromUnicode(QStringView in, QStringConverter::Stat
 }
 #endif
 
-void QStringConverter::State::clear()
+void QStringConverter::State::clear() noexcept
 {
     if (clearFn)
         clearFn(this);
diff --git a/src/corelib/text/qstringconverter_base.h b/src/corelib/text/qstringconverter_base.h
index ac147892ee..f726d95b82 100644
--- a/src/corelib/text/qstringconverter_base.h
+++ b/src/corelib/text/qstringconverter_base.h
@@ -73,14 +73,14 @@ public:
         constexpr State(Flags f = Flag::Default)
             : flags(f), state_data{0, 0, 0, 0} {}
         ~State() { clear(); }
-        State(State &&other)
+        State(State &&other) noexcept
             : flags(other.flags),
               remainingChars(other.remainingChars),
               invalidChars(other.invalidChars),
               d{other.d[0], other.d[1]},
               clearFn(other.clearFn)
         { other.clearFn = nullptr; }
-        State &operator=(State &&other)
+        State &operator=(State &&other) noexcept
         {
             clear();
             flags = other.flags;
@@ -92,7 +92,7 @@ public:
             other.clearFn = nullptr;
             return *this;
         }
-        Q_CORE_EXPORT void clear();
+        Q_CORE_EXPORT void clear() noexcept;
 
         Flags flags;
         int internalState = 0;
@@ -103,7 +103,7 @@ public:
             uint state_data[4];
             void *d[2];
         };
-        using ClearDataFn = void (*)(State *);
+        using ClearDataFn = void (*)(State *) noexcept;
         ClearDataFn clearFn = nullptr;
     private:
         Q_DISABLE_COPY(State)