QtCore: port all QMutexLocker users to qt_{scoped,unique}_lock

... except four instances in QCoreApplication that would conflict with
another change.

Replace a locally-defined MutexUnlocker with a call to unlock() +
qScopedGuard'ed lock() to avoid having to spell out the locker type
while we can't depend on C++17 CTAD, yet.

In QSettings, move the new mutex locker into and out of
initDefaultPaths(), such as is idiomatic for std::unique_lock, but
wasn't possible with QMutexLocker (which is not movable).

Change-Id: I23056e13ecaa76159db583c7dccc6e05715e0788
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

1 files changed, 4 insertions, 3 deletions

diff --git a/src/corelib/io/qloggingregistry.cpp b/src/corelib/io/qloggingregistry.cpp
index 7849dfd14c..e8eb18b4c1 100644
--- a/src/corelib/io/qloggingregistry.cpp
+++ b/src/corelib/io/qloggingregistry.cpp
@@ -41,6 +41,7 @@
 
 #include <QtCore/qfile.h>
 #include <QtCore/qlibraryinfo.h>
+#include <QtCore/private/qlocking_p.h>
 #include <QtCore/qstandardpaths.h>
 #include <QtCore/qtextstream.h>
 #include <QtCore/qdir.h>
@@ -356,7 +357,7 @@ void QLoggingRegistry::initializeRules()
 */
 void QLoggingRegistry::registerCategory(QLoggingCategory *cat, QtMsgType enableForLevel)
 {
-    QMutexLocker locker(&registryMutex);
+    const auto locker = qt_scoped_lock(registryMutex);
 
     if (!categories.contains(cat)) {
         categories.insert(cat, enableForLevel);
@@ -370,7 +371,7 @@ void QLoggingRegistry::registerCategory(QLoggingCategory *cat, QtMsgType enableF
 */
 void QLoggingRegistry::unregisterCategory(QLoggingCategory *cat)
 {
-    QMutexLocker locker(&registryMutex);
+    const auto locker = qt_scoped_lock(registryMutex);
     categories.remove(cat);
 }
 
@@ -413,7 +414,7 @@ void QLoggingRegistry::updateRules()
 QLoggingCategory::CategoryFilter
 QLoggingRegistry::installFilter(QLoggingCategory::CategoryFilter filter)
 {
-    QMutexLocker locker(&registryMutex);
+    const auto locker = qt_scoped_lock(registryMutex);
 
     if (!filter)
         filter = defaultCategoryFilter;