JUCE/modules/juce_gui_basics/native/juce_mac_FileChooser.mm

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

   This file is part of the JUCE library.
   Copyright (c) 2020 - Raw Material Software Limited

   JUCE is an open source library subject to commercial or open-source
   licensing.

   By using JUCE, you agree to the terms of both the JUCE 6 End-User License
   Agreement and JUCE Privacy Policy (both effective as of the 16th June 2020).

   End User License Agreement: www.juce.com/juce-6-licence
   Privacy Policy: www.juce.com/juce-privacy-policy

   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).

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

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

namespace juce
{

//==============================================================================
static NSMutableArray* createAllowedTypesArray (const StringArray& filters)
{
    if (filters.size() == 0)
        return nil;

    NSMutableArray* filterArray = [[[NSMutableArray alloc] init] autorelease];

    for (int i = 0; i < filters.size(); ++i)
    {
        // From OS X 10.6 you can only specify allowed extensions, so any filters containing wildcards
        // must be of the form "*.extension"
        jassert (filters[i] == "*"
                 || (filters[i].startsWith ("*.") && filters[i].lastIndexOfChar ('*') == 0));
        const String f (filters[i].replace ("*.", ""));

        if (f == "*")
            return nil;

        [filterArray addObject: juceStringToNS (f)];
    }

    return filterArray;
}

//==============================================================================
class FileChooser::Native     : public Component,
                                public FileChooser::Pimpl
{
public:
    Native (FileChooser& fileChooser, int flags, FilePreviewComponent* previewComponent)
        : owner (fileChooser), preview (previewComponent),
          selectsDirectories ((flags & FileBrowserComponent::canSelectDirectories)   != 0),
          selectsFiles       ((flags & FileBrowserComponent::canSelectFiles)         != 0),
          isSave             ((flags & FileBrowserComponent::saveMode)               != 0),
          selectMultiple     ((flags & FileBrowserComponent::canSelectMultipleItems) != 0)
    {
        setBounds (0, 0, 0, 0);
        setOpaque (true);

        static DelegateClass delegateClass;
        static SafeSavePanel safeSavePanel;
        static SafeOpenPanel safeOpenPanel;

        panel = isSave ? [safeSavePanel.createInstance() init]
                       : [safeOpenPanel.createInstance() init];

        delegate = [delegateClass.createInstance() init];
        object_setInstanceVariable (delegate, "cppObject", this);

        [panel setDelegate: delegate];

        filters.addTokens (owner.filters.replaceCharacters (",:", ";;"), ";", String());
        filters.trim();
        filters.removeEmptyStrings();

        [panel setTitle: juceStringToNS (owner.title)];
        [panel setAllowedFileTypes: createAllowedTypesArray (filters)];

        if (! isSave)
        {
            auto* openPanel = static_cast<NSOpenPanel*> (panel);

            [openPanel setCanChooseDirectories: selectsDirectories];
            [openPanel setCanChooseFiles: selectsFiles];
            [openPanel setAllowsMultipleSelection: selectMultiple];
            [openPanel setResolvesAliases: YES];

            if (owner.treatFilePackagesAsDirs)
                [openPanel setTreatsFilePackagesAsDirectories: YES];
        }

        if (preview != nullptr)
        {
            nsViewPreview = [[NSView alloc] initWithFrame: makeNSRect (preview->getLocalBounds())];
            [panel setAccessoryView: nsViewPreview];

            preview->addToDesktop (0, (void*) nsViewPreview);
            preview->setVisible (true);

            if (! isSave)
            {
                auto* openPanel = static_cast<NSOpenPanel*> (panel);
                [openPanel setAccessoryViewDisclosed: YES];
            }
        }

        if (isSave || selectsDirectories)
            [panel setCanCreateDirectories: YES];

        [panel setLevel:NSModalPanelWindowLevel];

        if (owner.startingFile.isDirectory())
        {
            startingDirectory = owner.startingFile.getFullPathName();
        }
        else
        {
            startingDirectory = owner.startingFile.getParentDirectory().getFullPathName();
            filename = owner.startingFile.getFileName();
        }

        [panel setDirectoryURL: createNSURLFromFile (startingDirectory)];
        [panel setNameFieldStringValue: juceStringToNS (filename)];
    }

    ~Native() override
    {
        exitModalState (0);

        if (preview != nullptr)
            preview->removeFromDesktop();

        removeFromDesktop();

        if (panel != nil)
        {
            [panel setDelegate: nil];

            if (nsViewPreview != nil)
            {
                [panel setAccessoryView: nil];

                [nsViewPreview release];

                nsViewPreview = nil;
                preview = nullptr;
            }

            [panel close];
            [panel release];
        }

        if (delegate != nil)
        {
            [delegate release];
            delegate = nil;
        }
    }

    void launch() override
    {
        if (panel != nil)
        {
            setAlwaysOnTop (juce_areThereAnyAlwaysOnTopWindows());
            addToDesktop (0);

            enterModalState (true);
            [panel beginWithCompletionHandler:CreateObjCBlock (this, &Native::finished)];

            if (preview != nullptr)
                preview->toFront (true);
        }
    }

    void runModally() override
    {
        ensurePanelSafe();

        std::unique_ptr<TemporaryMainMenuWithStandardCommands> tempMenu;

        if (JUCEApplicationBase::isStandaloneApp())
            tempMenu = std::make_unique<TemporaryMainMenuWithStandardCommands> (preview);

        jassert (panel != nil);
        auto result = [panel runModal];
        finished (result);
    }

    bool canModalEventBeSentToComponent (const Component* targetComponent) override
    {
        return TemporaryMainMenuWithStandardCommands::checkModalEvent (preview, targetComponent);
    }

private:
    //==============================================================================
    typedef NSObject<NSOpenSavePanelDelegate> DelegateType;

    void finished (NSInteger result)
    {
        Array<URL> chooserResults;

        exitModalState (0);

        if (panel != nil && result ==
                             #if defined (MAC_OS_X_VERSION_10_9) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_9
                               NSModalResponseOK)
                             #else
                               NSFileHandlingPanelOKButton)
                             #endif
        {
            auto addURLResult = [&chooserResults] (NSURL* urlToAdd)
            {
                auto scheme = nsStringToJuce ([urlToAdd scheme]);
                auto pathComponents = StringArray::fromTokens (nsStringToJuce ([urlToAdd path]), "/", {});

                for (auto& component : pathComponents)
                    component = URL::addEscapeChars (component, false);

                chooserResults.add (URL (scheme + "://" + pathComponents.joinIntoString ("/")));
            };

            if (isSave)
            {
                addURLResult ([panel URL]);
            }
            else
            {
                auto* openPanel = static_cast<NSOpenPanel*> (panel);
                auto urls = [openPanel URLs];

                for (unsigned int i = 0; i < [urls count]; ++i)
                    addURLResult ([urls objectAtIndex: i]);
            }
        }

        owner.finished (chooserResults);
    }

    bool shouldShowFilename (const String& filenameToTest)
    {
        const File f (filenameToTest);
        auto nsFilename = juceStringToNS (filenameToTest);

        for (int i = filters.size(); --i >= 0;)
            if (f.getFileName().matchesWildcard (filters[i], true))
                return true;

        return f.isDirectory()
                 && ! [[NSWorkspace sharedWorkspace] isFilePackageAtPath: nsFilename];
    }

    void panelSelectionDidChange (id sender)
    {
        jassert (sender == panel);
        ignoreUnused (sender);

        // NB: would need to extend FilePreviewComponent to handle the full list rather than just the first one
        if (preview != nullptr)
            preview->selectedFileChanged (File (getSelectedPaths()[0]));
    }

    StringArray getSelectedPaths() const
    {
        if (panel == nullptr)
            return {};

        StringArray paths;

        if (isSave)
        {
            paths.add (nsStringToJuce ([[panel URL] path]));
        }
        else
        {
            auto* urls = [static_cast<NSOpenPanel*> (panel) URLs];

            for (NSUInteger i = 0; i < [urls count]; ++i)
                paths.add (nsStringToJuce ([[urls objectAtIndex: i] path]));
        }

        return paths;
    }

    //==============================================================================
    FileChooser& owner;
    FilePreviewComponent* preview;
    NSView* nsViewPreview = nullptr;
    bool selectsDirectories, selectsFiles, isSave, selectMultiple;

    NSSavePanel* panel;
    DelegateType* delegate;

    StringArray filters;
    String startingDirectory, filename;

    void ensurePanelSafe()
    {
        // If you hit this, something (probably the plugin host) has modified the panel,
        // allowing the application to terminate while the panel's modal loop is running.
        // This is a very bad idea! Quitting from within the panel's modal loop may cause
        // your plugin/app destructor to run directly from within `runModally`, which will
        // dispose all app resources while they're still in use.
        // A safer alternative is to invoke the FileChooser with `launchAsync`, rather than
        // using the modal launchers.
        jassert ([panel preventsApplicationTerminationWhenModal]);
    }

    static BOOL preventsApplicationTerminationWhenModal() { return YES; }

    template <typename Base>
    struct SafeModalPanel : public ObjCClass<Base>
    {
        explicit SafeModalPanel (const char* name) : ObjCClass<Base> (name)
        {
            this->addMethod (@selector (preventsApplicationTerminationWhenModal),
                             preventsApplicationTerminationWhenModal,
                             "c@:");

            this->registerClass();
        }
    };

    struct SafeSavePanel : SafeModalPanel<NSSavePanel>
    {
        SafeSavePanel() : SafeModalPanel ("SaveSavePanel_") {}
    };

    struct SafeOpenPanel : SafeModalPanel<NSOpenPanel>
    {
        SafeOpenPanel() : SafeModalPanel ("SaveOpenPanel_") {}
    };

    //==============================================================================
    struct DelegateClass : public ObjCClass<DelegateType>
    {
        DelegateClass() : ObjCClass<DelegateType> ("JUCEFileChooser_")
        {
            addIvar<Native*> ("cppObject");

            addMethod (@selector (panel:shouldShowFilename:), shouldShowFilename,      "c@:@@");
            addMethod (@selector (panelSelectionDidChange:),  panelSelectionDidChange, "c@");

            addProtocol (@protocol (NSOpenSavePanelDelegate));

            registerClass();
        }

    private:
        static BOOL shouldShowFilename (id self, SEL, id /*sender*/, NSString* filename)
        {
            auto* _this = getIvar<Native*> (self, "cppObject");

            return _this->shouldShowFilename (nsStringToJuce (filename)) ? YES : NO;
        }

        static void panelSelectionDidChange (id self, SEL, id sender)
        {
            auto* _this = getIvar<Native*> (self, "cppObject");

            _this->panelSelectionDidChange (sender);
        }
    };

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Native)
};

FileChooser::Pimpl* FileChooser::showPlatformDialog (FileChooser& owner, int flags,
                                                     FilePreviewComponent* preview)
{
    return new FileChooser::Native (owner, flags, preview);
}

bool FileChooser::isPlatformDialogAvailable()
{
   #if JUCE_DISABLE_NATIVE_FILECHOOSERS
    return false;
   #else
    return true;
   #endif
}

}