JUCE/modules/juce_gui_basics/detail/juce_ScopedMessageBoxImpl.h

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

   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
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   framework to you, and you must discontinue the installation or download
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   Or:

   You may also use this code under the terms of the AGPLv3:
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   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::detail
{

//==============================================================================
class ScopedMessageBoxImpl
{
public:
    virtual ~ScopedMessageBoxImpl() = default;
    virtual void close() = 0;
};

//==============================================================================
class ConcreteScopedMessageBoxImpl : public ScopedMessageBoxImpl,
                                     public AsyncUpdater
{
public:
    static ScopedMessageBox show (std::unique_ptr<ScopedMessageBoxInterface>&& native,
                                  std::function<void (int)> callback)
    {
        return ScopedMessageBox (runAsync (std::move (native),
                                           rawToUniquePtr (ModalCallbackFunction::create (std::move (callback)))));
    }

    static int showUnmanaged (std::unique_ptr<ScopedMessageBoxInterface>&& native,
                              ModalComponentManager::Callback* cb)
    {
       #if JUCE_MODAL_LOOPS_PERMITTED
        if (cb == nullptr)
            return runSync (std::move (native));
       #endif

        runAsync (std::move (native), rawToUniquePtr (cb));

        return 0;
    }

    ~ConcreteScopedMessageBoxImpl() override
    {
        cancelPendingUpdate();
    }

    void close() override
    {
        cancelPendingUpdate();
        nativeImplementation->close();
        self.reset();
    }

private:
    static std::shared_ptr<ConcreteScopedMessageBoxImpl> runAsync (std::unique_ptr<ScopedMessageBoxInterface>&& p,
                                                                   std::unique_ptr<ModalComponentManager::Callback>&& c)
    {
        std::shared_ptr<ConcreteScopedMessageBoxImpl> result (new ConcreteScopedMessageBoxImpl (std::move (p), std::move (c)));
        result->self = result;
        result->triggerAsyncUpdate();
        return result;
    }

    static int runSync (std::unique_ptr<ScopedMessageBoxInterface>&& p)
    {
        auto local = std::move (p);
        return local != nullptr ? local->runSync() : 0;
    }

    explicit ConcreteScopedMessageBoxImpl (std::unique_ptr<ScopedMessageBoxInterface>&& p)
        : ConcreteScopedMessageBoxImpl (std::move (p), nullptr) {}

    ConcreteScopedMessageBoxImpl (std::unique_ptr<ScopedMessageBoxInterface>&& p,
                                  std::unique_ptr<ModalComponentManager::Callback>&& c)
        : callback (std::move (c)), nativeImplementation (std::move (p)) {}

    void handleAsyncUpdate() override
    {
        nativeImplementation->runAsync ([weakRecipient = std::weak_ptr<ConcreteScopedMessageBoxImpl> (self)] (int result)
                                        {
                                            const auto notifyRecipient = [result, weakRecipient]
                                            {
                                                if (const auto locked = weakRecipient.lock())
                                                {
                                                    if (auto* cb = locked->callback.get())
                                                        cb->modalStateFinished (result);

                                                    locked->self.reset();
                                                }
                                            };

                                            if (MessageManager::getInstance()->isThisTheMessageThread())
                                                notifyRecipient();
                                            else
                                                MessageManager::callAsync (notifyRecipient);
                                        });
    }

    std::unique_ptr<ModalComponentManager::Callback> callback;
    std::unique_ptr<ScopedMessageBoxInterface> nativeImplementation;

    /*  The 'old' native message box API doesn't have a concept of message box owners.
        Instead, message boxes have to clean up after themselves, once they're done displaying.
        To allow this mode of usage, the implementation keeps an owning reference to itself,
        which is cleared once the message box is closed or asked to quit. To display a native
        message box without a scoped lifetime, just create a Pimpl instance without using
        the ScopedMessageBox wrapper, and the Pimpl will destroy itself after it is dismissed.
    */
    std::shared_ptr<ConcreteScopedMessageBoxImpl> self;
};

} // namespace juce::detail