/*
  ==============================================================================

   This file is part of the JUCE framework.
   Copyright (c) Raw Material Software Limited

   JUCE is an open source framework subject to commercial or open source
   licensing.

   By downloading, installing, or using the JUCE framework, or combining the
   JUCE framework with any other source code, object code, content or any other
   copyrightable work, you agree to the terms of the JUCE End User Licence
   Agreement, and all incorporated terms including the JUCE Privacy Policy and
   the JUCE Website Terms of Service, as applicable, which will bind you. If you
   do not agree to the terms of these agreements, we will not license the JUCE
   framework to you, and you must discontinue the installation or download
   process and cease use of the JUCE framework.

   JUCE End User Licence Agreement: https://juce.com/legal/juce-8-licence/
   JUCE Privacy Policy: https://juce.com/juce-privacy-policy
   JUCE Website Terms of Service: https://juce.com/juce-website-terms-of-service/

   Or:

   You may also use this code under the terms of the AGPLv3:
   https://www.gnu.org/licenses/agpl-3.0.en.html

   THE JUCE FRAMEWORK IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL
   WARRANTIES, WHETHER EXPRESSED OR IMPLIED, INCLUDING WARRANTY OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

//==============================================================================
/**
    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.

    @tags{Core}
*/
template <class OwnerClass>
class LeakedObjectDetector
{
public:
    //==============================================================================
    LeakedObjectDetector() noexcept                                 { ++(getCounter().numObjects); }
    LeakedObjectDetector (const LeakedObjectDetector&) noexcept     { ++(getCounter().numObjects); }

    LeakedObjectDetector& operator= (const LeakedObjectDetector&) noexcept = default;

    ~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.

                Many errors like this are caused by using old-fashioned, non-RAII techniques for
                object management. If you're seeing this, it's a good idea to double-check
                that you're using std::unique_ptrs, OwnedArrays,
                ReferenceCountedObjects, etc, and avoiding manual calls to the 'delete'
                operator at all costs!

                You may also see this error if JUCE's shutdown code is called while an object
                containing a leak detector is still alive (perhaps declared as a namespace-scope
                static).
            */
            jassertfalse;
        }
    }

private:
    //==============================================================================
    class LeakCounter
    {
    public:
        LeakCounter() = default;

        ~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.

                    Many errors like this are caused by using old-fashioned, non-RAII techniques for
                    object management. If you're seeing this, it's a good idea to double-check
                    that you're using std::unique_ptrs, OwnedArrays,
                    ReferenceCountedObjects, etc, and avoiding manual calls to the 'delete'
                    operator at all costs!

                    You may also see this error if JUCE's shutdown code is called while an object
                    containing a leak detector is still alive (perhaps declared as a namespace-scope
                    static).
                */
                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

} // namespace juce
