Short live QtPrivate::{condition_variable,mutex}!

This is a temporary measure to work around an implementation bug on
Integrity: For all other platforms, QtPrivate::condition_variable is
just std::condition_variable. On Integrity, it's a class that wraps
QWaitCondition to provide the interface of std::condition_variable.

This allows the use of std::condition_variable across Qt without
running into the Integrity issue. Once we can depend on an more modern
Integrity toolchain, removing QtPrivate::condition_variable is a
simple mechanical change:

   s/QtPrivate::condition_variable/std::condition_variable/g;
   s/QtPrivate::mutex/std::mutex/g;

Task-number: QTBUG-78450
Change-Id: I293a99d1cdc48691817b926aa51ecd84556e5e90
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

3 files changed, 163 insertions, 8 deletions

diff --git a/src/corelib/thread/qwaitcondition_p.h b/src/corelib/thread/qwaitcondition_p.h
new file mode 100644
index 0000000000..5133e52e92
--- /dev/null
+++ b/src/corelib/thread/qwaitcondition_p.h
@@ -0,0 +1,153 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 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 QWAITCONDITION_P_H
+#define QWAITCONDITION_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists for the convenience
+// of qmutex.cpp, qmutex_unix.cpp, and qmutex_win.cpp.  This header
+// file may change from version to version without notice, or even be
+// removed.
+//
+// We mean it.
+//
+
+#include <QtCore/QWaitCondition>
+#include <QtCore/QMutex>
+#include <QtCore/QDeadlineTimer>
+
+#include <condition_variable>
+#include <mutex>
+
+QT_BEGIN_NAMESPACE
+
+namespace QtPrivate
+{
+
+#if defined(Q_OS_INTEGRITY)
+
+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>
+    std::cv_status wait_for(std::unique_lock<QtPrivate::mutex> &lock,
+                            const std::chrono::duration<Rep, Period> &d)
+    {
+        return QWaitCondition::wait(lock.mutex(), QDeadlineTimer{d})
+                ? std::cv_status::no_timeout
+                : std::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>
+    std::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})
+                ? std::cv_status::no_timeout
+                : std::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 // Integrity
+
+using mutex = std::mutex;
+using condition_variable = std::condition_variable;
+
+#endif // Integrity
+
+} // namespace QtPrivate
+
+QT_END_NAMESPACE
+
+#endif /* QWAITCONDITION_P_H */
diff --git a/src/corelib/thread/thread.pri b/src/corelib/thread/thread.pri
index 9fc9af0e65..25cf68a324 100644
--- a/src/corelib/thread/thread.pri
+++ b/src/corelib/thread/thread.pri
@@ -6,6 +6,7 @@ HEADERS += \
     thread/qrunnable.h \
     thread/qthread.h \
     thread/qthreadstorage.h \
+    thread/qwaitcondition_p.h \
     thread/qwaitcondition.h
 
 SOURCES += \
diff --git a/src/testlib/qtestcase.cpp b/src/testlib/qtestcase.cpp
index e29897abee..5c87844fcd 100644
--- a/src/testlib/qtestcase.cpp
+++ b/src/testlib/qtestcase.cpp
@@ -59,6 +59,7 @@
 #include <QtCore/qtemporarydir.h>
 #include <QtCore/qthread.h>
 #include <QtCore/private/qlocking_p.h>
+#include <QtCore/private/qwaitcondition_p.h>
 
 #include <QtCore/qtestsupport_core.h>
 
@@ -1017,15 +1018,15 @@ class WatchDog : public QThread
         ThreadEnd,
     };
 
-    bool waitFor(std::unique_lock<std::mutex> &m, Expectation e) {
-        auto expectation = [this, e] { return expecting != e; };
+    bool waitFor(std::unique_lock<QtPrivate::mutex> &m, Expectation e) {
+        auto expectationChanged = [this, e] { return expecting != e; };
         switch (e) {
         case TestFunctionEnd:
-            return waitCondition.wait_for(m, defaultTimeout(), expectation);
+            return waitCondition.wait_for(m, defaultTimeout(), expectationChanged);
         case ThreadStart:
         case ThreadEnd:
         case TestFunctionStart:
-            waitCondition.wait(m, expectation);
+            waitCondition.wait(m, expectationChanged);
             return true;
         }
         Q_UNREACHABLE();
@@ -1035,7 +1036,7 @@ class WatchDog : public QThread
 public:
     WatchDog()
     {
-        std::unique_lock<std::mutex> locker(mutex);
+        auto locker = qt_unique_lock(mutex);
         expecting = ThreadStart;
         start();
         waitFor(locker, ThreadStart);
@@ -1062,7 +1063,7 @@ public:
     }
 
     void run() override {
-        std::unique_lock<std::mutex> locker(mutex);
+        auto locker = qt_unique_lock(mutex);
         expecting = TestFunctionStart;
         waitCondition.notify_all();
         while (true) {
@@ -1082,8 +1083,8 @@ public:
     }
 
 private:
-    std::mutex mutex;
-    std::condition_variable waitCondition;
+    QtPrivate::mutex mutex;
+    QtPrivate::condition_variable waitCondition;
     Expectation expecting;
 };