QtCore: Remove std::mutex and std::condition_variable fallbacks

They existed because INTEGRITY hadn't yet been updated to the C++11
Standard Library, with a minor for broken MinGW cross-compilation builds
that forgot to enable gthreads support in libstdc++. The former appears
to have been since fixed and the latter is a massive toolchain
configuration mistake.

Change-Id: I63b988479db546dabffcfffd1766b55132371f9b
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

src/corelib/thread/qreadwritelock.cpp

@@ -411,7 +411,7 @@ void QReadWriteLock::unlock()
     }
 }
 
-bool QReadWriteLockPrivate::lockForRead(std::unique_lock<QtPrivate::mutex> &lock, QDeadlineTimer timeout)
+bool QReadWriteLockPrivate::lockForRead(std::unique_lock<std::mutex> &lock, QDeadlineTimer timeout)
 {
     Q_ASSERT(!mutex.try_lock()); // mutex must be locked when entering this function
 
@@ -432,7 +432,7 @@ bool QReadWriteLockPrivate::lockForRead(std::unique_lock<QtPrivate::mutex> &lock
     return true;
 }
 
-bool QReadWriteLockPrivate::lockForWrite(std::unique_lock<QtPrivate::mutex> &lock, QDeadlineTimer timeout)
+bool QReadWriteLockPrivate::lockForWrite(std::unique_lock<std::mutex> &lock, QDeadlineTimer timeout)
 {
     Q_ASSERT(!mutex.try_lock()); // mutex must be locked when entering this function
 

src/corelib/thread/qreadwritelock_p.h

@@ -45,10 +45,10 @@ public:
     explicit QReadWriteLockPrivate(bool isRecursive = false)
         : recursive(isRecursive) {}
 
-    alignas(QtPrivate::IdealMutexAlignment) QtPrivate::condition_variable writerCond;
-    QtPrivate::condition_variable readerCond;
+    alignas(QtPrivate::IdealMutexAlignment) std::condition_variable writerCond;
+    std::condition_variable readerCond;
 
-    alignas(QtPrivate::IdealMutexAlignment) QtPrivate::mutex mutex;
+    alignas(QtPrivate::IdealMutexAlignment) std::mutex mutex;
     int readerCount = 0;
     int writerCount = 0;
     int waitingReaders = 0;
@@ -56,8 +56,8 @@ public:
     const bool recursive;
 
     //Called with the mutex locked
-    bool lockForWrite(std::unique_lock<QtPrivate::mutex> &lock, QDeadlineTimer timeout);
-    bool lockForRead(std::unique_lock<QtPrivate::mutex> &lock, QDeadlineTimer timeout);
+    bool lockForWrite(std::unique_lock<std::mutex> &lock, QDeadlineTimer timeout);
+    bool lockForRead(std::unique_lock<std::mutex> &lock, QDeadlineTimer timeout);
     void unlock();
 
     //memory management

src/corelib/thread/qsemaphore.cpp

@@ -255,15 +255,15 @@ namespace { namespace QtSemaphorePrivate {
 using namespace QtPrivate;
 struct Layout1
 {
-    alignas(IdealMutexAlignment) QtPrivate::mutex mutex;
+    alignas(IdealMutexAlignment) std::mutex mutex;
     qsizetype avail = 0;
-    alignas(IdealMutexAlignment) QtPrivate::condition_variable cond;
+    alignas(IdealMutexAlignment) std::condition_variable cond;
 };
 
 struct Layout2
 {
-    alignas(IdealMutexAlignment) QtPrivate::mutex mutex;
-    alignas(IdealMutexAlignment) QtPrivate::condition_variable cond;
+    alignas(IdealMutexAlignment) std::mutex mutex;
+    alignas(IdealMutexAlignment) std::condition_variable cond;
     qsizetype avail = 0;
 };
 

src/corelib/thread/qwaitcondition_p.h

@@ -19,116 +19,18 @@
 #include <QtCore/QDeadlineTimer>
 #include <QtCore/private/qglobal_p.h>
 
-// This header always defines a class called "mutex" and one called
-// "condition_variable", so those mustn't be used to mark ELF symbol
-// visibility. Don't add more classes to this header!
-// ELFVERSION:stop
-
 #include <condition_variable>
 #include <mutex>
 
-// There's no feature macro for C++11 std::mutex, so we use the C++14 one
-// for shared_mutex to detect it.
-// Needed for: MinGW without gthreads, Integrity
-#if __has_include(<shared_mutex>)
-#  include <shared_mutex>
-#endif
-
 QT_BEGIN_NAMESPACE
 
 namespace QtPrivate {
-
-#if !defined(__cpp_lib_shared_timed_mutex)
-
-enum class cv_status { no_timeout, timeout };
-class condition_variable;
-
-class mutex : private QMutex
-{
-    friend class QtPrivate::condition_variable;
-
-public:
-    // all special member functions are ok!
-    // do not expose the (QMutex::Recursive) ctor
-    // don't use 'using QMutex::lock;' etc as those have the wrong noexcept
-
-    void lock() { return QMutex::lock(); }
-    void unlock() { return QMutex::unlock(); }
-    bool try_lock() { return QMutex::tryLock(); }
-};
-
-class condition_variable : private QWaitCondition
-{
-public:
-    // all special member functions are ok!
-
-    void notify_one() { QWaitCondition::wakeOne(); }
-    void notify_all() { QWaitCondition::wakeAll(); }
-
-    void wait(std::unique_lock<QtPrivate::mutex> &lock) { QWaitCondition::wait(lock.mutex()); }
-    template <class Predicate>
-    void wait(std::unique_lock<QtPrivate::mutex> &lock, Predicate p)
-    {
-        while (!p())
-            wait(lock);
-    }
-
-    template <typename Rep, typename Period>
-    cv_status wait_for(std::unique_lock<QtPrivate::mutex> &lock,
-                            const std::chrono::duration<Rep, Period> &d)
-    {
-        return QWaitCondition::wait(lock.mutex(), QDeadlineTimer{d})
-                ? cv_status::no_timeout
-                : cv_status::timeout;
-    }
-    template <typename Rep, typename Period, typename Predicate>
-    bool wait_for(std::unique_lock<QtPrivate::mutex> &lock,
-                  const std::chrono::duration<Rep, Period> &d, Predicate p)
-    {
-        const auto timer = QDeadlineTimer{d};
-        while (!p()) {
-            if (!QWaitCondition::wait(lock.mutex(), timer))
-                return p();
-        }
-        return true;
-    }
-
-    template <typename Clock, typename Duration>
-    cv_status wait_until(std::unique_lock<QtPrivate::mutex> &lock,
-                              const std::chrono::time_point<Clock, Duration> &t)
-    {
-        return QWaitCondition::wait(lock.mutex(), QDeadlineTimer{t})
-                ? cv_status::no_timeout
-                : cv_status::timeout;
-    }
-
-    template <typename Clock, typename Duration, typename Predicate>
-    bool wait_until(std::unique_lock<QtPrivate::mutex> &lock,
-                    const std::chrono::time_point<Clock, Duration> &t, Predicate p)
-    {
-        const auto timer = QDeadlineTimer{t};
-        while (!p()) {
-            if (!QWaitCondition::wait(lock.mutex(), timer))
-                return p();
-        }
-        return true;
-    }
-
-};
-
-#else // C++11 threads
-
-using mutex = std::mutex;
-using condition_variable = std::condition_variable;
-
-#endif // C++11 threads
-
 // Ideal alignment for mutex and condition_variable: it's the hardware
 // interference size (size of a cache line) if the types are likely to contain
 // the actual data structures, otherwise just that of a pointer.
 static constexpr quintptr IdealMutexAlignment =
-        sizeof(QtPrivate::mutex) > sizeof(void *) &&
-        sizeof(QtPrivate::condition_variable) > sizeof(void *) ?
+        sizeof(std::mutex) > sizeof(void *) &&
+        sizeof(std::condition_variable) > sizeof(void *) ?
             64 : alignof(void*);
 
 } // namespace QtPrivate

src/testlib/qtestcase.cpp

@@ -1231,7 +1231,7 @@ class WatchDog : public QThread
     static constexpr Expectation combine(Expectation e, size_t gen) noexcept
     { return Expectation{e | (gen << GenerationShift)}; }
 
-    bool waitFor(std::unique_lock<QtPrivate::mutex> &m, Expectation e)
+    bool waitFor(std::unique_lock<std::mutex> &m, Expectation e)
     {
         auto expectationChanged = [this, e] { return expecting.load(std::memory_order_relaxed) != e; };
         switch (state(e)) {
@@ -1310,8 +1310,8 @@ public:
     }
 
 private:
-    QtPrivate::mutex mutex;
-    QtPrivate::condition_variable waitCondition;
+    std::mutex mutex;
+    std::condition_variable waitCondition;
     std::atomic<Expectation> expecting;
 };