forked from qt-creator/qt-creator
8c288bf05f
To get rid of QDoc warnings. Change-Id: Idd39b7ae4327798c376f424c94d6617bcaee2258 Reviewed-by: hjk <hjk@qt.io>
103 lines
2.2 KiB
C++
103 lines
2.2 KiB
C++
// Copyright (C) 2016 The Qt Company Ltd.
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// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
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#include "guard.h"
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#include "qtcassert.h"
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/*!
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\class Utils::Guard
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\inmodule QtCreator
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\brief The Guard class implements a recursive guard with locking mechanism.
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It may be used as an alternative to QSignalBlocker.
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QSignalBlocker blocks all signals of the object
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which is usually not desirable. It may also block signals
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which are needed internally by the object itself.
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The Guard and GuardLocker classes don't block signals at all.
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When calling a object's method which may in turn emit a signal
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which you are connected to, and you want to ignore
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this notification, you should keep the Guard object
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as your class member and declare the GuardLocker object
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just before calling the mentioned method, like:
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\code
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class MyClass : public QObject
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{
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\dots
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private:
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Guard updateGuard; // member of your class
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};
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\dots
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void MyClass::updateOtherObject()
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{
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GuardLocker updatelocker(updateGuard);
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otherObject->update(); // this may trigger a signal
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}
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\endcode
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Inside a slot which is connected to the other's object signal
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you may check if the guard is locked and ignore the further
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operations in this case:
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\code
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void MyClass::otherObjectUpdated()
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{
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if (updateGuard.isLocked())
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return;
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// we didn't trigger the update
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// so do update now
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\dots
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}
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\endcode
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The GuardLocker unlocks the Guard in its destructor.
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The Guard object is recursive, you may declare many GuardLocker
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objects for the same Guard instance and the Guard will be locked
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as long as at least one GuardLocker object created for the Guard
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is in scope.
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*/
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namespace Utils {
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Guard::Guard() = default;
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Guard::~Guard()
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{
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QTC_CHECK(m_lockCount == 0);
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}
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bool Guard::isLocked() const
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{
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return m_lockCount;
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}
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void Guard::lock()
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{
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++m_lockCount;
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}
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void Guard::unlock()
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{
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QTC_CHECK(m_lockCount > 0);
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--m_lockCount;
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}
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GuardLocker::GuardLocker(Guard &guard)
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: m_guard(guard)
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{
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++m_guard.m_lockCount;
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}
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GuardLocker::~GuardLocker()
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{
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--m_guard.m_lockCount;
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}
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} // namespace Utils
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