JUCE/modules/juce_gui_extra/documents/juce_FileBasedDocument.cpp

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

   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/
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   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
{

//==============================================================================
class FileBasedDocument::Pimpl
{
private:
    //==============================================================================
    class SafeParentPointer
    {
    public:
        SafeParentPointer (Pimpl* parent, bool isAsync)
            : ptr (parent), shouldCheck (isAsync)
        {}

        Pimpl* operator->() const noexcept
        {
            return ptr.get();
        }

        bool operator== (Pimpl* object) const noexcept   { return ptr.get() == object; }
        bool operator!= (Pimpl* object) const noexcept   { return ptr.get() != object; }

        bool shouldExitAsyncCallback() const noexcept
        {
            return shouldCheck && ptr == nullptr;
        }

    private:
        WeakReference<Pimpl> ptr;
        bool shouldCheck = false;
    };

public:
    //==============================================================================
    Pimpl (FileBasedDocument& parent_,
           const String& fileExtension_,
           const String& fileWildcard_,
           const String& openFileDialogTitle_,
           const String& saveFileDialogTitle_)
        : document (parent_),
          fileExtension (fileExtension_),
          fileWildcard (fileWildcard_),
          openFileDialogTitle (openFileDialogTitle_),
          saveFileDialogTitle (saveFileDialogTitle_)
    {
    }

    //==============================================================================
    bool hasChangedSinceSaved() const
    {
        return changedSinceSave;
    }

    void setChangedFlag (bool hasChanged)
    {
        if (changedSinceSave != hasChanged)
        {
            changedSinceSave = hasChanged;
            document.sendChangeMessage();
        }
    }

    void changed()
    {
        changedSinceSave = true;
        document.sendChangeMessage();
    }

    //==============================================================================
    Result loadFrom (const File& newFile, bool showMessageOnFailure, bool showWaitCursor = true)
    {
        SafeParentPointer parent { this, false };
        auto result = Result::ok();
        loadFromImpl (parent,
                      newFile,
                      showMessageOnFailure,
                      showWaitCursor,
                      [this] (const File& file, const auto& callback) { callback (document.loadDocument (file)); },
                      [&result] (Result r) { result = r; });
        return result;
    }

    void loadFromAsync (const File& newFile,
                        bool showMessageOnFailure,
                        std::function<void (Result)> callback)
    {
        SafeParentPointer parent { this, true };
        loadFromImpl (parent,
                      newFile,
                      showMessageOnFailure,
                      false,
                      [parent] (const File& file, auto cb)
                      {
                          if (parent != nullptr)
                              parent->document.loadDocumentAsync (file, std::move (cb));
                      },
                      std::move (callback));
    }

    //==============================================================================
   #if JUCE_MODAL_LOOPS_PERMITTED
    Result loadFromUserSpecifiedFile (bool showMessageOnFailure)
    {
        FileChooser fc (openFileDialogTitle,
                        document.getLastDocumentOpened(),
                        fileWildcard);

        if (fc.browseForFileToOpen())
            return loadFrom (fc.getResult(), showMessageOnFailure);

        return Result::fail (TRANS ("User cancelled"));
    }
   #endif

    void loadFromUserSpecifiedFileAsync (const bool showMessageOnFailure, std::function<void (Result)> callback)
    {
        asyncFc = std::make_unique<FileChooser> (openFileDialogTitle,
                                                 document.getLastDocumentOpened(),
                                                 fileWildcard);

        asyncFc->launchAsync (FileBrowserComponent::openMode | FileBrowserComponent::canSelectFiles,
                              [this, showMessageOnFailure, cb = std::move (callback)] (const FileChooser& fc)
        {
            auto chosenFile = fc.getResult();

            if (chosenFile == File{})
            {
                NullCheckedInvocation::invoke (cb, Result::fail (TRANS ("User cancelled")));
                return;
            }

            WeakReference<Pimpl> parent { this };
            loadFromAsync (chosenFile, showMessageOnFailure, [parent, cb] (Result result)
            {
                if (parent != nullptr)
                    NullCheckedInvocation::invoke (cb, result);
            });

            asyncFc = nullptr;
        });
    }

    //==============================================================================
   #if JUCE_MODAL_LOOPS_PERMITTED
    FileBasedDocument::SaveResult save (bool askUserForFileIfNotSpecified,
                                        bool showMessageOnFailure)
    {
        return saveAs (documentFile,
                       false,
                       askUserForFileIfNotSpecified,
                       showMessageOnFailure);
    }
   #endif

    void saveAsync (bool askUserForFileIfNotSpecified,
                    bool showMessageOnFailure,
                    std::function<void (SaveResult)> callback)
    {
        saveAsAsync (documentFile,
                     false,
                     askUserForFileIfNotSpecified,
                     showMessageOnFailure,
                     std::move (callback));
    }

    //==============================================================================
   #if JUCE_MODAL_LOOPS_PERMITTED
    FileBasedDocument::SaveResult saveIfNeededAndUserAgrees()
    {
        SafeParentPointer parent { this, false };
        SaveResult result;
        saveIfNeededAndUserAgreesImpl (parent,
                                       [&result] (SaveResult r) { result = r; },
                                       AskToSaveChangesSync { *this },
                                       SaveSync { *this });
        return result;
    }
   #endif

    void saveIfNeededAndUserAgreesAsync (std::function<void (SaveResult)> callback)
    {
        SafeParentPointer parent { this, true };

        saveIfNeededAndUserAgreesImpl (parent,
                                       std::move (callback),
                                       [] (SafeParentPointer ptr, auto cb)
                                       {
                                           if (ptr != nullptr)
                                               ptr->askToSaveChangesAsync (ptr, std::move (cb));
                                       },
                                       [parent] (bool askUserForFileIfNotSpecified,
                                                 bool showMessageOnFailure,
                                                 auto cb)
                                       {
                                           if (parent != nullptr)
                                               parent->saveAsync (askUserForFileIfNotSpecified,
                                                                  showMessageOnFailure,
                                                                  std::move (cb));
                                       });
    }

    //==============================================================================
   #if JUCE_MODAL_LOOPS_PERMITTED
    FileBasedDocument::SaveResult saveAs (const File& newFile,
                                          bool warnAboutOverwritingExistingFiles,
                                          bool askUserForFileIfNotSpecified,
                                          bool showMessageOnFailure,
                                          bool showWaitCursor = true)
    {
        SafeParentPointer parent { this, false };
        SaveResult result{};
        saveAsSyncImpl (parent,
                        newFile,
                        warnAboutOverwritingExistingFiles,
                        askUserForFileIfNotSpecified,
                        showMessageOnFailure,
                        [&result] (SaveResult r) { result = r; },
                        showWaitCursor);
        return result;
    }
    #endif

    void saveAsAsync (const File& newFile,
                      bool warnAboutOverwritingExistingFiles,
                      bool askUserForFileIfNotSpecified,
                      bool showMessageOnFailure,
                      std::function<void (SaveResult)> callback)
    {
        SafeParentPointer parent { this, true };
        saveAsAsyncImpl (parent,
                         newFile,
                         warnAboutOverwritingExistingFiles,
                         askUserForFileIfNotSpecified,
                         showMessageOnFailure,
                         std::move (callback),
                         false);
    }

    //==============================================================================
   #if JUCE_MODAL_LOOPS_PERMITTED
    FileBasedDocument::SaveResult saveAsInteractive (bool warnAboutOverwritingExistingFiles)
    {
        SafeParentPointer parent { this, false };
        SaveResult result{};
        saveAsInteractiveSyncImpl (parent,
                                   warnAboutOverwritingExistingFiles,
                                   [&result] (SaveResult r) { result = r; });
        return result;
    }
   #endif

    void saveAsInteractiveAsync (bool warnAboutOverwritingExistingFiles,
                                 std::function<void (SaveResult)> callback)
    {
        SafeParentPointer parent { this, true };
        saveAsInteractiveAsyncImpl (parent,
                                    warnAboutOverwritingExistingFiles,
                                    std::move (callback));
    }

    //==============================================================================
    const File& getFile() const
    {
        return documentFile;
    }

    void setFile (const File& newFile)
    {
        if (documentFile != newFile)
        {
            documentFile = newFile;
            changed();
        }
    }

    //==============================================================================
    const String& getFileExtension() const
    {
        return fileExtension;
    }

private:
    //==============================================================================
    template <typename DoLoadDocument>
    void loadFromImpl (SafeParentPointer parent,
                       const File& newFile,
                       bool showMessageOnFailure,
                       bool showWaitCursor,
                       DoLoadDocument&& doLoadDocument,
                       std::function<void (Result)> completed)
    {
        if (parent.shouldExitAsyncCallback())
            return;

        if (showWaitCursor)
            MouseCursor::showWaitCursor();

        auto oldFile = documentFile;
        documentFile = newFile;

        auto tidyUp = [parent, newFile, oldFile, showMessageOnFailure, showWaitCursor, completed] (Result result)
        {
            if (parent.shouldExitAsyncCallback())
                return;

            parent->documentFile = oldFile;

            if (showWaitCursor)
                MouseCursor::hideWaitCursor();

            if (showMessageOnFailure)
            {
                auto options = MessageBoxOptions::makeOptionsOk (MessageBoxIconType::WarningIcon,
                                                                 TRANS ("Failed to open file..."),
                                                                 TRANS ("There was an error while trying to load the file: FLNM")
                                                                         .replace ("FLNM", "\n" + newFile.getFullPathName())
                                                                     + "\n\n"
                                                                     + result.getErrorMessage());
                parent->messageBox = AlertWindow::showScopedAsync (options, nullptr);
            }

            NullCheckedInvocation::invoke (completed, result);
        };

        if (newFile.existsAsFile())
        {
            auto afterLoading = [parent,
                                 showWaitCursor,
                                 newFile,
                                 cb = std::move (completed),
                                 tidyUp] (Result result)
            {
                if (result.wasOk())
                {
                    parent->setChangedFlag (false);

                    if (showWaitCursor)
                        MouseCursor::hideWaitCursor();

                    parent->document.setLastDocumentOpened (newFile);
                    NullCheckedInvocation::invoke (cb, result);
                    return;
                }

                tidyUp (result);
            };

            doLoadDocument (newFile, std::move (afterLoading));

            return;
        }

        tidyUp (Result::fail (TRANS ("The file doesn't exist")));
    }

    //==============================================================================
    template <typename DoAskToSaveChanges, typename DoSave>
    void saveIfNeededAndUserAgreesImpl (SafeParentPointer parent,
                                        std::function<void (SaveResult)> completed,
                                        DoAskToSaveChanges&& doAskToSaveChanges,
                                        DoSave&& doSave)
    {
        if (parent.shouldExitAsyncCallback())
            return;

        if (! hasChangedSinceSaved())
        {
            NullCheckedInvocation::invoke (completed, savedOk);
            return;
        }

        auto afterAsking = [save = std::forward<DoSave> (doSave),
                            cb = std::move (completed)] (SafeParentPointer ptr,
                                                         int alertResult)
        {
            if (ptr.shouldExitAsyncCallback())
                return;

            switch (alertResult)
            {
                case 1:  // save changes
                    save (true, true, [ptr, cb] (SaveResult result)
                    {
                        if (ptr.shouldExitAsyncCallback())
                            return;

                        NullCheckedInvocation::invoke (cb, result);
                    });
                    return;

                case 2:  // discard changes
                    NullCheckedInvocation::invoke (cb, savedOk);
                    return;
            }

            NullCheckedInvocation::invoke (cb, userCancelledSave);
        };

        doAskToSaveChanges (parent, std::move (afterAsking));
    }

    //==============================================================================
    MessageBoxOptions getAskToSaveChangesOptions() const
    {
        return MessageBoxOptions::makeOptionsYesNoCancel (MessageBoxIconType::QuestionIcon,
                                                          TRANS ("Closing document..."),
                                                          TRANS ("Do you want to save the changes to \"DCNM\"?")
                                                                  .replace ("DCNM", document.getDocumentTitle()),
                                                          TRANS ("Save"),
                                                          TRANS ("Discard changes"),
                                                          TRANS ("Cancel"));
    }

    void askToSaveChangesAsync (SafeParentPointer parent,
                                std::function<void (SafeParentPointer, int)> callback)
    {
        messageBox = AlertWindow::showScopedAsync (getAskToSaveChangesOptions(),
                                                   [parent, cb = std::move (callback)] (int alertResult)
                                                   {
                                                       if (parent != nullptr)
                                                           cb (parent, alertResult);
                                                   });
    }

   #if JUCE_MODAL_LOOPS_PERMITTED
    int askToSaveChangesSync()
    {
        return AlertWindow::show (getAskToSaveChangesOptions());
    }
   #endif

    //==============================================================================
    template <typename DoSaveDocument>
    void saveInternal (SafeParentPointer parent,
                       const File& newFile,
                       bool showMessageOnFailure,
                       bool showWaitCursor,
                       std::function<void (SaveResult)> afterSave,
                       DoSaveDocument&& doSaveDocument)
    {
        if (showWaitCursor)
            MouseCursor::showWaitCursor();

        auto oldFile = documentFile;
        documentFile = newFile;

        doSaveDocument (newFile, [parent,
                                  showMessageOnFailure,
                                  showWaitCursor,
                                  oldFile,
                                  newFile,
                                  after = std::move (afterSave)] (Result result)
        {
            if (parent.shouldExitAsyncCallback())
            {
                if (showWaitCursor)
                    MouseCursor::hideWaitCursor();

                return;
            }

            if (result.wasOk())
            {
                parent->setChangedFlag (false);

                if (showWaitCursor)
                    MouseCursor::hideWaitCursor();

                parent->document.sendChangeMessage(); // because the filename may have changed

                NullCheckedInvocation::invoke (after, savedOk);
                return;
            }

            parent->documentFile = oldFile;

            if (showWaitCursor)
                MouseCursor::hideWaitCursor();

            if (showMessageOnFailure)
            {
                auto options = MessageBoxOptions::makeOptionsOk (MessageBoxIconType::WarningIcon,
                                                                 TRANS ("Error writing to file..."),
                                                                 TRANS ("An error occurred while trying to save \"DCNM\" to the file: FLNM")
                                                                         .replace ("DCNM", parent->document.getDocumentTitle())
                                                                         .replace ("FLNM", "\n" + newFile.getFullPathName())
                                                                     + "\n\n"
                                                                     + result.getErrorMessage());
                parent->messageBox = AlertWindow::showScopedAsync (options, nullptr);
            }

            parent->document.sendChangeMessage(); // because the filename may have changed
            NullCheckedInvocation::invoke (after, failedToWriteToFile);
        });
    }

    template <typename DoSaveAsInteractive, typename DoAskToOverwriteFile, typename DoSaveDocument>
    void saveAsImpl (SafeParentPointer parent,
                     const File& newFile,
                     bool warnAboutOverwritingExistingFiles,
                     bool askUserForFileIfNotSpecified,
                     bool showMessageOnFailure,
                     std::function<void (SaveResult)> callback,
                     bool showWaitCursor,
                     DoSaveAsInteractive&& doSaveAsInteractive,
                     DoAskToOverwriteFile&& doAskToOverwriteFile,
                     DoSaveDocument&& doSaveDocument)
    {
        if (parent.shouldExitAsyncCallback())
            return;

        if (newFile == File())
        {
            if (askUserForFileIfNotSpecified)
            {
                doSaveAsInteractive (parent, true, std::move (callback));
                return;
            }

            // can't save to an unspecified file
            jassertfalse;

            NullCheckedInvocation::invoke (callback, failedToWriteToFile);
            return;
        }

        auto saveInternalHelper = [parent,
                                   callback,
                                   newFile,
                                   showMessageOnFailure,
                                   showWaitCursor,
                                   saveDocument = std::forward<DoSaveDocument> (doSaveDocument)]
        {
            if (! parent.shouldExitAsyncCallback())
                parent->saveInternal (parent,
                                      newFile,
                                      showMessageOnFailure,
                                      showWaitCursor,
                                      callback,
                                      saveDocument);
        };

        if (warnAboutOverwritingExistingFiles && newFile.exists())
        {
            auto afterAsking = [cb = std::move (callback),
                                saveInternalHelper] (SafeParentPointer ptr,
                                                     bool shouldOverwrite)
            {
                if (ptr.shouldExitAsyncCallback())
                    return;

                if (shouldOverwrite)
                    saveInternalHelper();
                else
                    NullCheckedInvocation::invoke (cb, userCancelledSave);
            };
            doAskToOverwriteFile (parent, newFile, std::move (afterAsking));
            return;
        }

        saveInternalHelper();
    }

    void saveAsAsyncImpl (SafeParentPointer parent,
                          const File& newFile,
                          bool warnAboutOverwritingExistingFiles,
                          bool askUserForFileIfNotSpecified,
                          bool showMessageOnFailure,
                          std::function<void (SaveResult)> callback,
                          bool showWaitCursor)
    {
        saveAsImpl (parent,
                    newFile,
                    warnAboutOverwritingExistingFiles,
                    askUserForFileIfNotSpecified,
                    showMessageOnFailure,
                    std::move (callback),
                    showWaitCursor,
                    [] (SafeParentPointer ptr, bool warnAboutOverwriting, auto cb)
                    {
                        if (ptr != nullptr)
                            ptr->saveAsInteractiveAsyncImpl (ptr, warnAboutOverwriting, std::move (cb));
                    },
                    [] (SafeParentPointer ptr, const File& destination, std::function<void (SafeParentPointer, bool)> cb)
                    {
                        if (ptr != nullptr)
                            ptr->askToOverwriteFileAsync (ptr, destination, std::move (cb));
                    },
                    [parent] (const File& destination, std::function<void (Result)> cb)
                    {
                        if (parent != nullptr)
                            parent->document.saveDocumentAsync (destination, std::move (cb));
                    });
    }

    //==============================================================================
    void saveAsInteractiveAsyncImpl (SafeParentPointer parent,
                                     bool warnAboutOverwritingExistingFiles,
                                     std::function<void (SaveResult)> callback)
    {
        if (parent == nullptr)
            return;

        saveAsInteractiveImpl (parent,
                               warnAboutOverwritingExistingFiles,
                               std::move (callback),
                               [] (SafeParentPointer ptr, bool warnAboutOverwriting, auto cb)
                               {
                                   if (ptr != nullptr)
                                       ptr->getSaveAsFilenameAsync (ptr, warnAboutOverwriting, std::move (cb));
                               },
                               [] (SafeParentPointer ptr,
                                   const File& newFile,
                                   bool warnAboutOverwriting,
                                   bool askUserForFileIfNotSpecified,
                                   bool showMessageOnFailure,
                                   auto cb,
                                   bool showWaitCursor)
                               {
                                   if (ptr != nullptr)
                                       ptr->saveAsAsyncImpl (ptr,
                                                             newFile,
                                                             warnAboutOverwriting,
                                                             askUserForFileIfNotSpecified,
                                                             showMessageOnFailure,
                                                             std::move (cb),
                                                             showWaitCursor);
                               },
                               [] (SafeParentPointer ptr, const File& destination, auto cb)
                               {
                                   if (ptr != nullptr)
                                       ptr->askToOverwriteFileAsync (ptr, destination, std::move (cb));
                               });
    }

    //==============================================================================
    MessageBoxOptions getAskToOverwriteFileOptions (const File& newFile) const
    {
        return MessageBoxOptions::makeOptionsOkCancel (MessageBoxIconType::WarningIcon,
                                                       TRANS ("File already exists"),
                                                       TRANS ("There's already a file called: FLNM")
                                                               .replace ("FLNM", newFile.getFullPathName())
                                                           + "\n\n"
                                                           + TRANS ("Are you sure you want to overwrite it?"),
                                                       TRANS ("Overwrite"),
                                                       TRANS ("Cancel"));
    }

    void askToOverwriteFileAsync (SafeParentPointer parent,
                                  const File& newFile,
                                  std::function<void (SafeParentPointer, bool)> callback)
    {
        if (parent == nullptr)
            return;

        messageBox = AlertWindow::showScopedAsync (getAskToOverwriteFileOptions (newFile),
                                                   [parent, cb = std::move (callback)] (int r)
                                                   {
                                                       if (parent != nullptr)
                                                           NullCheckedInvocation::invoke (cb, parent, r != 1);
                                                   });
    }

   #if JUCE_MODAL_LOOPS_PERMITTED
    bool askToOverwriteFileSync (const File& newFile)
    {
        return AlertWindow::show (getAskToOverwriteFileOptions (newFile));
    }
   #endif

    //==============================================================================
    void getSaveAsFilenameAsync (SafeParentPointer parent,
                                 bool warnAboutOverwritingExistingFiles,
                                 std::function<void (SafeParentPointer, const File&)> callback)
    {
        asyncFc = getInteractiveFileChooser();

        auto flags = FileBrowserComponent::saveMode | FileBrowserComponent::canSelectFiles;

        if (warnAboutOverwritingExistingFiles)
            flags |= FileBrowserComponent::warnAboutOverwriting;

        asyncFc->launchAsync (flags, [parent, cb = std::move (callback)] (const FileChooser& fc)
        {
            cb (parent, fc.getResult());
        });
    }

    //==============================================================================
    template <typename DoSelectFilename, typename DoSaveAs, typename DoAskToOverwriteFile>
    void saveAsInteractiveImpl (SafeParentPointer parent,
                                bool warnAboutOverwritingExistingFiles,
                                std::function<void (SaveResult)> callback,
                                DoSelectFilename&& doSelectFilename,
                                DoSaveAs&& doSaveAs,
                                DoAskToOverwriteFile&& doAskToOverwriteFile)
    {
        doSelectFilename (parent,
                          warnAboutOverwritingExistingFiles,
                          [saveAs = std::forward<DoSaveAs> (doSaveAs),
                           askToOverwriteFile = std::forward<DoAskToOverwriteFile> (doAskToOverwriteFile),
                           cb = std::move (callback)] (SafeParentPointer parentPtr, File chosen)
        {
            if (parentPtr.shouldExitAsyncCallback())
                return;

            if (chosen == File{})
            {
                NullCheckedInvocation::invoke (cb, userCancelledSave);
                return;
            }

            auto updateAndSaveAs = [parentPtr, saveAs, cb] (const File& chosenFile)
            {
                if (parentPtr.shouldExitAsyncCallback())
                    return;

                parentPtr->document.setLastDocumentOpened (chosenFile);
                saveAs (parentPtr, chosenFile, false, false, true, cb, false);
            };

            if (chosen.getFileExtension().isEmpty())
            {
                chosen = chosen.withFileExtension (parentPtr->fileExtension);

                if (chosen.exists())
                {
                    auto afterAsking = [chosen, updateAndSaveAs, cb] (SafeParentPointer overwritePtr,
                                                                            bool overwrite)
                    {
                        if (overwritePtr.shouldExitAsyncCallback())
                            return;

                        if (overwrite)
                            updateAndSaveAs (chosen);
                        else
                            NullCheckedInvocation::invoke (cb, userCancelledSave);
                    };

                    askToOverwriteFile (parentPtr, chosen, std::move (afterAsking));
                    return;
                }
            }

            updateAndSaveAs (chosen);
        });
    }

    //==============================================================================
    std::unique_ptr<FileChooser> getInteractiveFileChooser()
    {
        auto f = documentFile.existsAsFile() ? documentFile : document.getLastDocumentOpened();

        auto legalFilename = File::createLegalFileName (document.getDocumentTitle());

        if (legalFilename.isEmpty())
            legalFilename = "unnamed";

        f = (f.existsAsFile() || f.getParentDirectory().isDirectory())
            ? f.getSiblingFile (legalFilename)
            : File::getSpecialLocation (File::userDocumentsDirectory).getChildFile (legalFilename);

        f = document.getSuggestedSaveAsFile (f);

        return std::make_unique<FileChooser> (saveFileDialogTitle,
                                              f,
                                              fileWildcard);
    }

    //==============================================================================
   #if JUCE_MODAL_LOOPS_PERMITTED
    struct SaveAsInteractiveSyncImpl
    {
        template <typename... Ts>
        void operator() (Ts&&... ts) const noexcept
        {
            p.saveAsInteractiveSyncImpl (std::forward<Ts> (ts)...);
        }

        Pimpl& p;
    };

    struct AskToOverwriteFileSync
    {
        template <typename... Ts>
        void operator() (Ts&&... ts) const noexcept
        {
            p.askToOverwriteFileSync (std::forward<Ts> (ts)...);
        }

        Pimpl& p;
    };

    struct AskToSaveChangesSync
    {
        template <typename... Ts>
        void operator() (Ts&&... ts) const noexcept
        {
            p.askToSaveChangesSync (std::forward<Ts> (ts)...);
        }

        Pimpl& p;
    };

    struct SaveSync
    {
        template <typename... Ts>
        void operator() (Ts&&... ts) const noexcept
        {
            p.saveSync (std::forward<Ts> (ts)...);
        }

        Pimpl& p;
    };

    struct GetSaveAsFilenameSync
    {
        template <typename... Ts>
        void operator() (Ts&&... ts) const noexcept
        {
            p.getSaveAsFilenameSync (std::forward<Ts> (ts)...);
        }

        Pimpl& p;
    };

    struct SaveAsSyncImpl
    {
        template <typename... Ts>
        void operator() (Ts&&... ts) const noexcept
        {
            p.saveAsSyncImpl (std::forward<Ts> (ts)...);
        }

        Pimpl& p;
    };

    //==============================================================================
    void saveAsSyncImpl (SafeParentPointer parent,
                         const File& newFile,
                         bool warnAboutOverwritingExistingFiles,
                         bool askUserForFileIfNotSpecified,
                         bool showMessageOnFailure,
                         std::function<void (SaveResult)> callback,
                         bool showWaitCursor)
    {
        saveAsImpl (parent,
                    newFile,
                    warnAboutOverwritingExistingFiles,
                    askUserForFileIfNotSpecified,
                    showMessageOnFailure,
                    std::move (callback),
                    showWaitCursor,
                    SaveAsInteractiveSyncImpl { *this },
                    AskToOverwriteFileSync { *this },
                    [this] (const File& file, const auto& cb) { cb (document.saveDocument (file)); });
    }

    //==============================================================================
    template <typename Callback>
    void askToSaveChangesSync (SafeParentPointer parent, Callback&& callback)
    {
        callback (parent, askToSaveChangesSync());
    }

    //==============================================================================
    void saveAsInteractiveSyncImpl (SafeParentPointer parent,
                                    bool warnAboutOverwritingExistingFiles,
                                    std::function<void (SaveResult)> callback)
    {
        saveAsInteractiveImpl (parent,
                               warnAboutOverwritingExistingFiles,
                               std::move (callback),
                               GetSaveAsFilenameSync { *this },
                               SaveAsSyncImpl { *this },
                               AskToOverwriteFileSync { *this });
    }

    //==============================================================================
    template <typename Callback>
    void askToOverwriteFileSync (SafeParentPointer parent,
                                 const File& newFile,
                                 Callback&& callback)
    {
        callback (parent, askToOverwriteFileSync (newFile));
    }

    //==============================================================================
    template <typename Callback>
    void saveSync (bool askUserForFileIfNotSpecified,
                   bool showMessageOnFailure,
                   Callback&& callback)
    {
        callback (save (askUserForFileIfNotSpecified, showMessageOnFailure));
    }

    //==============================================================================
    template <typename Callback>
    void getSaveAsFilenameSync (SafeParentPointer parent,
                                bool warnAboutOverwritingExistingFiles,
                                Callback&& callback)
    {
        auto fc = getInteractiveFileChooser();

        if (fc->browseForFileToSave (warnAboutOverwritingExistingFiles))
        {
            callback (parent, fc->getResult());
            return;
        }

        callback (parent, {});
    }
   #endif

    //==============================================================================
    FileBasedDocument& document;

    File documentFile;
    bool changedSinceSave = false;
    String fileExtension, fileWildcard, openFileDialogTitle, saveFileDialogTitle;
    std::unique_ptr<FileChooser> asyncFc;
    ScopedMessageBox messageBox;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Pimpl)
    JUCE_DECLARE_WEAK_REFERENCEABLE (Pimpl)
};

//==============================================================================
FileBasedDocument::FileBasedDocument (const String& fileExtension,
                                      const String& fileWildcard,
                                      const String& openFileDialogTitle,
                                      const String& saveFileDialogTitle)
    : pimpl (new Pimpl (*this,
                        fileExtension,
                        fileWildcard,
                        openFileDialogTitle,
                        saveFileDialogTitle))
{
}

FileBasedDocument::~FileBasedDocument() = default;

//==============================================================================
bool FileBasedDocument::hasChangedSinceSaved() const
{
    return pimpl->hasChangedSinceSaved();
}

void FileBasedDocument::setChangedFlag (bool hasChanged)
{
    pimpl->setChangedFlag (hasChanged);
}

void FileBasedDocument::changed()
{
    pimpl->changed();
}

//==============================================================================
Result FileBasedDocument::loadFrom (const File& fileToLoadFrom,
                                    bool showMessageOnFailure,
                                    bool showWaitCursor)
{
    return pimpl->loadFrom (fileToLoadFrom, showMessageOnFailure, showWaitCursor);
}

void FileBasedDocument::loadFromAsync (const File& fileToLoadFrom,
                                       bool showMessageOnFailure,
                                       std::function<void (Result)> callback)
{
    pimpl->loadFromAsync (fileToLoadFrom, showMessageOnFailure, std::move (callback));
}

//==============================================================================
#if JUCE_MODAL_LOOPS_PERMITTED
Result FileBasedDocument::loadFromUserSpecifiedFile (bool showMessageOnFailure)
{
    return pimpl->loadFromUserSpecifiedFile (showMessageOnFailure);
}
#endif

void FileBasedDocument::loadFromUserSpecifiedFileAsync (const bool showMessageOnFailure,
                                                        std::function<void (Result)> callback)
{
    pimpl->loadFromUserSpecifiedFileAsync (showMessageOnFailure, std::move (callback));
}

//==============================================================================
#if JUCE_MODAL_LOOPS_PERMITTED
FileBasedDocument::SaveResult FileBasedDocument::save (bool askUserForFileIfNotSpecified,
                                                       bool showMessageOnFailure)
{
    return pimpl->save (askUserForFileIfNotSpecified, showMessageOnFailure);
}
#endif

void FileBasedDocument::saveAsync (bool askUserForFileIfNotSpecified,
                                   bool showMessageOnFailure,
                                   std::function<void (SaveResult)> callback)
{
    pimpl->saveAsync (askUserForFileIfNotSpecified, showMessageOnFailure, std::move (callback));
}

//==============================================================================
#if JUCE_MODAL_LOOPS_PERMITTED
FileBasedDocument::SaveResult FileBasedDocument::saveIfNeededAndUserAgrees()
{
    return pimpl->saveIfNeededAndUserAgrees();
}
#endif

void FileBasedDocument::saveIfNeededAndUserAgreesAsync (std::function<void (SaveResult)> callback)
{
    pimpl->saveIfNeededAndUserAgreesAsync (std::move (callback));
}

//==============================================================================
#if JUCE_MODAL_LOOPS_PERMITTED
FileBasedDocument::SaveResult FileBasedDocument::saveAs (const File& newFile,
                                                         bool warnAboutOverwritingExistingFiles,
                                                         bool askUserForFileIfNotSpecified,
                                                         bool showMessageOnFailure,
                                                         bool showWaitCursor)
{
    return pimpl->saveAs (newFile,
                          warnAboutOverwritingExistingFiles,
                          askUserForFileIfNotSpecified,
                          showMessageOnFailure,
                          showWaitCursor);
}
#endif

void FileBasedDocument::saveAsAsync (const File& newFile,
                                     bool warnAboutOverwritingExistingFiles,
                                     bool askUserForFileIfNotSpecified,
                                     bool showMessageOnFailure,
                                     std::function<void (SaveResult)> callback)
{
    pimpl->saveAsAsync (newFile,
                        warnAboutOverwritingExistingFiles,
                        askUserForFileIfNotSpecified,
                        showMessageOnFailure,
                        std::move (callback));
}

//==============================================================================
#if JUCE_MODAL_LOOPS_PERMITTED
FileBasedDocument::SaveResult FileBasedDocument::saveAsInteractive (bool warnAboutOverwritingExistingFiles)
{
    return pimpl->saveAsInteractive (warnAboutOverwritingExistingFiles);
}
#endif

void FileBasedDocument::saveAsInteractiveAsync (bool warnAboutOverwritingExistingFiles,
                                                std::function<void (SaveResult)> callback)
{
    pimpl->saveAsInteractiveAsync (warnAboutOverwritingExistingFiles, std::move (callback));
}

//==============================================================================
const File& FileBasedDocument::getFile() const
{
    return pimpl->getFile();
}

void FileBasedDocument::setFile (const File& newFile)
{
    pimpl->setFile (newFile);
}

//==============================================================================
void FileBasedDocument::loadDocumentAsync (const File& file, std::function<void (Result)> callback)
{
    const auto result = loadDocument (file);
    NullCheckedInvocation::invoke (callback, result);
}

void FileBasedDocument::saveDocumentAsync (const File& file, std::function<void (Result)> callback)
{
    const auto result = saveDocument (file);
    NullCheckedInvocation::invoke (callback, result);
}

File FileBasedDocument::getSuggestedSaveAsFile (const File& defaultFile)
{
    return defaultFile.withFileExtension (pimpl->getFileExtension()).getNonexistentSibling (true);
}

} // namespace juce