From 98897b26f8c63f848562cb4d8401bbe2521dffd3 Mon Sep 17 00:00:00 2001
From: Martchus <martchus@gmx.net>
Date: Thu, 10 Mar 2016 22:15:16 +0100
Subject: [PATCH] added locker classes intended to be used with QMutex

---
 CMakeLists.txt     |  2 ++
 misc/adoptlocker.h | 38 +++++++++++++++++++++++++++++++
 misc/trylocker.h   | 57 ++++++++++++++++++++++++++++++++++++++++++++++
 qtutilities.pro    |  4 +++-
 4 files changed, 100 insertions(+), 1 deletion(-)
 create mode 100644 misc/adoptlocker.h
 create mode 100644 misc/trylocker.h

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0730d5d..4fc632c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,6 +8,8 @@ set(HEADER_FILES
     misc/desktoputils.h
     misc/xmlparsermacros.h
     misc/undefxmlparsermacros.h
+    misc/trylocker.h
+    misc/adoptlocker.h
     models/checklistmodel.h
     resources/qtconfigarguments.h
     resources/resources.h
diff --git a/misc/adoptlocker.h b/misc/adoptlocker.h
new file mode 100644
index 0000000..4bc860e
--- /dev/null
+++ b/misc/adoptlocker.h
@@ -0,0 +1,38 @@
+#ifndef ADOPTLOCKER_H
+#define ADOPTLOCKER_H
+
+#include <QtGlobal>
+
+QT_FORWARD_DECLARE_CLASS(QMutex)
+
+namespace ThreadingUtils {
+
+/*!
+ * \brief Like QMutexLocker, but assumes that the mutex has already been locked.
+ */
+template<typename Mutex = QMutex>
+class AdoptLocker
+{
+public:
+    /*!
+     * \brief Constructs the locker for the specified \a mutex.
+     */
+    AdoptLocker(Mutex &mutex) :
+        m_mutex(mutex)
+    {}
+
+    /*!
+     * \brief Unlocks the mutex specified when constructing the instance.
+     */
+    ~AdoptLocker()
+    {
+        m_mutex.unlock();
+    }
+
+private:
+    Mutex &m_mutex;
+};
+
+}
+
+#endif // ADOPTLOCKER_H
diff --git a/misc/trylocker.h b/misc/trylocker.h
new file mode 100644
index 0000000..7d432ae
--- /dev/null
+++ b/misc/trylocker.h
@@ -0,0 +1,57 @@
+#ifndef TRYLOCKER_H
+#define TRYLOCKER_H
+
+#include <QtGlobal>
+
+QT_FORWARD_DECLARE_CLASS(QMutex)
+
+namespace ThreadingUtils {
+
+/*!
+ * \brief Like QMutexLocker, but it just tries to lock the mutex.
+ */
+template<typename Mutex = QMutex>
+class TryLocker
+{
+public:
+    /*!
+     * \brief Tries to lock the specified mutex.
+     */
+    TryLocker(Mutex &mutex) :
+        m_mutex(mutex.tryLock() ? &mutex : nullptr)
+    {}
+
+    /*!
+     * \brief Unlocks the mutex specified when constructing.
+     * \remarks Does nothing if the mutex couldn't be locked in the first place.
+     */
+    ~TryLocker()
+    {
+        if(m_mutex) {
+            m_mutex->unlock();
+        }
+    }
+
+    /*!
+     * \brief Returns whether the mutex could be locked.
+     */
+    bool isLocked() const
+    {
+        return m_mutex != nullptr;
+    }
+
+    /*!
+     * \brief Returns whether the mutex could be locked.
+     */
+    operator bool() const
+    {
+        return m_mutex != nullptr;
+    }
+
+private:
+    Mutex *m_mutex;
+};
+
+}
+
+#endif // TRYLOCKER_H
diff --git a/qtutilities.pro b/qtutilities.pro
index 0a40e87..c4174f2 100644
--- a/qtutilities.pro
+++ b/qtutilities.pro
@@ -32,7 +32,9 @@ HEADERS += \
     misc/dialogutils.h \
     misc/desktoputils.h \
     misc/xmlparsermacros.h \
-    misc/undefxmlparsermacros.h
+    misc/undefxmlparsermacros.h \
+    misc/trylocker.h \
+    misc/adoptlocker.h
 
 SOURCES += resources/resources.cpp \
     models/checklistmodel.cpp \