To use it, simply declare a JUCE_LEAK_DETECTOR(YourClassName) inside a private section
of the class declaration. E.g.
@code
class MyClass
{
public:
MyClass();
void blahBlah();
private:
JUCE_LEAK_DETECTOR (MyClass)
};
@endcode
@see JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR, LeakedObjectDetector
*/
#define JUCE_LEAK_DETECTOR(OwnerClass) \
friend class juce::LeakedObjectDetector<OwnerClass>; \
static const char* getLeakedObjectClassName() noexcept { return #OwnerClass; } \
juce::LeakedObjectDetector<OwnerClass> JUCE_JOIN_MACRO (leakDetector, __LINE__);
往上查找，看說明，大體明白是使用靜態變量來計數，當應用程序銷燬時，靜成變量的析構函數得到調用，這個時候檢查計數是否爲零，如果不爲零說明沒有刪除掉。原來是這個原理
//==============================================================================
/**
Embedding an instance of this class inside another class can be used as a low-overhead
way of detecting leaked instances.
This class keeps an internal static count of the number of instances that are
active, so that when the app is shutdown and the static destructors are called,
it can check whether there are any left-over instances that may have been leaked.
To use it, use the JUCE_LEAK_DETECTOR macro as a simple way to put one in your
class declaration. Have a look through the juce codebase for examples, it's used
in most of the classes.
*/
template <class OwnerClass>
class LeakedObjectDetector
{
public:
//==============================================================================
LeakedObjectDetector() noexcept { ++(getCounter().numObjects); }
LeakedObjectDetector (const LeakedObjectDetector&) noexcept { ++(getCounter().numObjects); }
~LeakedObjectDetector()
{
if (--(getCounter().numObjects) < 0)
{
DBG ("*** Dangling pointer deletion! Class: " << getLeakedObjectClassName());
/** If you hit this, then you've managed to delete more instances of this class than you've
created.. That indicates that you're deleting some dangling pointers.
Note that although this assertion will have been triggered during a destructor, it might
not be this particular deletion that's at fault - the incorrect one may have happened
at an earlier point in the program, and simply not been detected until now.
Most errors like this are caused by using old-fashioned, non-RAII techniques for
your object management. Tut, tut. Always, always use ScopedPointers, OwnedArrays,
ReferenceCountedObjects, etc, and avoid the 'delete' operator at all costs!
*/
jassertfalse;
}
}
private:
//==============================================================================
class LeakCounter
{
public:
LeakCounter() noexcept {}
~LeakCounter()
{
if (numObjects.value > 0)
{
DBG ("*** Leaked objects detected: " << numObjects.value << " instance(s) of class " << getLeakedObjectClassName());
/** If you hit this, then you've leaked one or more objects of the type specified by
the 'OwnerClass' template parameter - the name should have been printed by the line above.
If you're leaking, it's probably because you're using old-fashioned, non-RAII techniques for
your object management. Tut, tut. Always, always use ScopedPointers, OwnedArrays,
ReferenceCountedObjects, etc, and avoid the 'delete' operator at all costs!
*/
jassertfalse;
}
}
Atomic<int> numObjects;
};
static const char* getLeakedObjectClassName()
{
return OwnerClass::getLeakedObjectClassName();
}
static LeakCounter& getCounter() noexcept
{
static LeakCounter counter;
return counter;
}
};
//==============================================================================
#if DOXYGEN || ! defined (JUCE_LEAK_DETECTOR)
#if (DOXYGEN || JUCE_CHECK_MEMORY_LEAKS)
/** This macro lets you embed a leak-detecting object inside a class.
To use it, simply declare a JUCE_LEAK_DETECTOR(YourClassName) inside a private section
of the class declaration. E.g.
@code
class MyClass
{
public:
MyClass();
void blahBlah();
private:
JUCE_LEAK_DETECTOR (MyClass)
};
@endcode
@see JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR, LeakedObjectDetector
*/
#define JUCE_LEAK_DETECTOR(OwnerClass) \
friend class juce::LeakedObjectDetector<OwnerClass>; \
static const char* getLeakedObjectClassName() noexcept { return #OwnerClass; } \
juce::LeakedObjectDetector<OwnerClass> JUCE_JOIN_MACRO (leakDetector, __LINE__);
#else
#define JUCE_LEAK_DETECTOR(OwnerClass)
#endif
#endif
#endif // JUCE_LEAKEDOBJECTDETECTOR_H_INCLUDED