FileChooser: Hide chooser when it leaves scope on Windows

extras/Build/juceaide/Main.cpp

@@ -495,7 +495,7 @@ int main (int argc, char** argv)
         std::transform (argv, argv + argc, std::back_inserter (arguments), getString);
 
         juce::ArgumentList argumentList { arguments.front(),
-                                          juce::StringArray (arguments.data() + 1, arguments.size() - 1) };
+                                          juce::StringArray (arguments.data() + 1, (int) arguments.size() - 1) };
 
         using Fn = typename std::add_lvalue_reference<decltype (writeBinaryData)>::type;
 

modules/juce_gui_basics/components/juce_Component.h

@@ -2179,10 +2179,7 @@ public:
         operator ComponentType*() const noexcept              { return getComponent(); }
 
         /** Returns the component that this pointer refers to, or null if the component no longer exists. */
-        ComponentType* operator->() noexcept                  { return getComponent(); }
-
-        /** Returns the component that this pointer refers to, or null if the component no longer exists. */
-        const ComponentType* operator->() const noexcept      { return getComponent(); }
+        ComponentType* operator->() const noexcept            { return getComponent(); }
 
         /** If the component is valid, this deletes it and sets this pointer to null. */
         void deleteAndZero()                                  { delete getComponent(); }

modules/juce_gui_basics/filebrowser/juce_FileChooser.cpp

@@ -158,7 +158,7 @@ bool FileChooser::showDialog (const int flags, FilePreviewComponent* const previ
 {
     FocusRestorer focusRestorer;
 
-    pimpl.reset (createPimpl (flags, previewComp));
+    pimpl = createPimpl (flags, previewComp);
     pimpl->runModally();
 
     // ensure that the finished function was invoked
@@ -179,12 +179,12 @@ void FileChooser::launchAsync (int flags, std::function<void (const FileChooser&
 
     asyncCallback = std::move (callback);
 
-    pimpl.reset (createPimpl (flags, previewComp));
+    pimpl = createPimpl (flags, previewComp);
     pimpl->launch();
 }
 
 
-FileChooser::Pimpl* FileChooser::createPimpl (int flags, FilePreviewComponent* previewComp)
+std::unique_ptr<FileChooser::Pimpl> FileChooser::createPimpl (int flags, FilePreviewComponent* previewComp)
 {
     results.clear();
 
@@ -214,10 +214,8 @@ FileChooser::Pimpl* FileChooser::createPimpl (int flags, FilePreviewComponent* p
     {
         return showPlatformDialog (*this, flags, previewComp);
     }
-    else
-    {
-        return new NonNative (*this, flags, previewComp);
-    }
+
+    return std::make_unique<NonNative> (*this, flags, previewComp);
 }
 
 Array<File> FileChooser::getResults() const noexcept

modules/juce_gui_basics/filebrowser/juce_FileChooser.h

@@ -325,12 +325,11 @@ private:
         virtual void runModally() = 0;
     };
 
-    std::unique_ptr<Pimpl> pimpl;
+    std::shared_ptr<Pimpl> pimpl;
 
     //==============================================================================
-    Pimpl* createPimpl (int, FilePreviewComponent*);
-    static Pimpl* showPlatformDialog (FileChooser&, int,
-                                      FilePreviewComponent*);
+    std::unique_ptr<Pimpl> createPimpl (int, FilePreviewComponent*);
+    static std::unique_ptr<Pimpl> showPlatformDialog (FileChooser&, int, FilePreviewComponent*);
 
     class NonNative;
     friend class NonNative;

modules/juce_gui_basics/native/juce_android_FileChooser.cpp

@@ -219,11 +219,11 @@ private:
 
 FileChooser::Native* FileChooser::Native::currentFileChooser = nullptr;
 
-FileChooser::Pimpl* FileChooser::showPlatformDialog (FileChooser& owner, int flags,
-                                                     FilePreviewComponent*)
+std::unique_ptr<FileChooser::Pimpl> FileChooser::showPlatformDialog (FileChooser& owner, int flags,
+                                                                     FilePreviewComponent*)
 {
     if (FileChooser::Native::currentFileChooser == nullptr)
-        return new FileChooser::Native (owner, flags);
+        return std::make_unique<FileChooser::Native> (owner, flags);
 
     // there can only be one file chooser on Android at a once
     jassertfalse;

modules/juce_gui_basics/native/juce_ios_FileChooser.mm

@@ -379,10 +379,10 @@ bool FileChooser::isPlatformDialogAvailable()
    #endif
 }
 
-FileChooser::Pimpl* FileChooser::showPlatformDialog (FileChooser& owner, int flags,
-                                                     FilePreviewComponent*)
+std::unique_ptr<FileChooser::Pimpl> FileChooser::showPlatformDialog (FileChooser& owner, int flags,
+                                                                     FilePreviewComponent*)
 {
-    return new FileChooser::Native (owner, flags);
+    return std::make_unique<FileChooser::Native> (owner, flags);
 }
 
 #if JUCE_DEPRECATION_IGNORED

modules/juce_gui_basics/native/juce_linux_FileChooser.cpp

@@ -256,9 +256,9 @@ bool FileChooser::isPlatformDialogAvailable()
    #endif
 }
 
-FileChooser::Pimpl* FileChooser::showPlatformDialog (FileChooser& owner, int flags, FilePreviewComponent*)
+std::unique_ptr<FileChooser::Pimpl> FileChooser::showPlatformDialog (FileChooser& owner, int flags, FilePreviewComponent*)
 {
-    return new Native (owner, flags);
+    return std::make_unique<Native> (owner, flags);
 }
 
 } // namespace juce

modules/juce_gui_basics/native/juce_mac_FileChooser.mm

@@ -377,10 +377,10 @@ private:
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Native)
 };
 
-FileChooser::Pimpl* FileChooser::showPlatformDialog (FileChooser& owner, int flags,
-                                                     FilePreviewComponent* preview)
+std::unique_ptr<FileChooser::Pimpl> FileChooser::showPlatformDialog (FileChooser& owner, int flags,
+                                                                     FilePreviewComponent* preview)
 {
-    return new FileChooser::Native (owner, flags, preview);
+    return std::make_unique<FileChooser::Native> (owner, flags, preview);
 }
 
 bool FileChooser::isPlatformDialogAvailable()

modules/juce_gui_basics/native/juce_win32_FileChooser.cpp

@@ -26,32 +26,23 @@
 namespace juce
 {
 
-// Win32NativeFileChooser needs to be a reference counted object as there
-// is no way for the parent to know when the dialog HWND has actually been
-// created without pumping the message thread (which is forbidden when modal
-// loops are disabled). However, the HWND pointer is the only way to cancel
-// the dialog box. This means that the actual native FileChooser HWND may
-// not have been created yet when the user deletes JUCE's FileChooser class. If this
-// occurs the Win32NativeFileChooser will still have a reference count of 1 and will
-// simply delete itself immediately once the HWND will have been created a while later.
-class Win32NativeFileChooser  : public ReferenceCountedObject,
+class Win32NativeFileChooser  : public std::enable_shared_from_this<Win32NativeFileChooser>,
                                 private Thread
 {
 public:
-    using Ptr = ReferenceCountedObjectPtr<Win32NativeFileChooser>;
-
     enum { charsAvailableForResult = 32768 };
 
     Win32NativeFileChooser (Component* parent, int flags, FilePreviewComponent* previewComp,
                             const File& startingFile, const String& titleToUse,
                             const String& filtersToUse)
         : Thread ("Native Win32 FileChooser"),
-          owner (parent), title (titleToUse), filtersString (filtersToUse.replaceCharacter (',', ';')),
+          owner (parent),
+          title (titleToUse),
+          filtersString (filtersToUse.replaceCharacter (',', ';')),
           selectsDirectories ((flags & FileBrowserComponent::canSelectDirectories)   != 0),
           isSave             ((flags & FileBrowserComponent::saveMode)               != 0),
           warnAboutOverwrite ((flags & FileBrowserComponent::warnAboutOverwriting)   != 0),
-          selectMultiple     ((flags & FileBrowserComponent::canSelectMultipleItems) != 0),
-          nativeDialogRef (nullptr), shouldCancel (0)
+          selectMultiple     ((flags & FileBrowserComponent::canSelectMultipleItems) != 0)
     {
         auto parentDirectory = startingFile.getParentDirectory();
 
@@ -95,10 +86,7 @@ public:
         {
             jassert (! isThreadRunning());
 
-            threadHasReference.reset();
             startThread();
-
-            threadHasReference.wait (-1);
         }
         else
         {
@@ -112,7 +100,7 @@ public:
         ScopedLock lock (deletingDialog);
 
         customComponent = nullptr;
-        shouldCancel.set (1);
+        shouldCancel = true;
 
         if (auto hwnd = nativeDialogRef.get())
             EndDialog (hwnd, 0);
@@ -151,12 +139,11 @@ private:
     };
 
     //==============================================================================
-    Component::SafePointer<Component> owner;
+    const Component::SafePointer<Component> owner;
     String title, filtersString;
     std::unique_ptr<CustomComponentHolder> customComponent;
     String initialPath, returnedString;
 
-    WaitableEvent threadHasReference;
     CriticalSection deletingDialog;
 
     bool selectsDirectories, isSave, warnAboutOverwrite, selectMultiple;
@@ -164,15 +151,15 @@ private:
     HeapBlock<WCHAR> files;
     HeapBlock<WCHAR> filters;
 
-    Atomic<HWND> nativeDialogRef;
-    Atomic<int>  shouldCancel;
+    Atomic<HWND> nativeDialogRef { nullptr };
+    bool shouldCancel = false;
 
     struct FreeLPWSTR
     {
         void operator() (LPWSTR ptr) const noexcept { CoTaskMemFree (ptr); }
     };
 
-    bool showDialog (IFileDialog& dialog, bool async) const
+    bool showDialog (IFileDialog& dialog, bool async)
     {
         FILEOPENDIALOGOPTIONS flags = {};
 
@@ -235,7 +222,49 @@ private:
         if (! selectsDirectories && FAILED (dialog.SetFileTypes (numElementsInArray (spec), spec)))
             return false;
 
-        return dialog.Show (static_cast<HWND> (async ? nullptr : owner->getWindowHandle())) == S_OK;
+        struct Events  : public ComBaseClassHelper<IFileDialogEvents>
+        {
+            explicit Events (Win32NativeFileChooser& o) : owner (o) {}
+
+            JUCE_COMRESULT OnTypeChange (IFileDialog* d) override
+            {
+                HWND hwnd = nullptr;
+                IUnknown_GetWindow (d, &hwnd);
+
+                ScopedLock lock (owner.deletingDialog);
+
+                if (hwnd != nullptr)
+                    owner.nativeDialogRef = hwnd;
+
+                return owner.shouldCancel ? S_FALSE : S_OK;
+            }
+
+            JUCE_COMRESULT OnFolderChanging (IFileDialog*, IShellItem*) override                                { return S_OK; }
+            JUCE_COMRESULT OnFileOk (IFileDialog*) override                                                     { return S_OK; }
+            JUCE_COMRESULT OnFolderChange (IFileDialog*) override                                               { return S_OK; }
+            JUCE_COMRESULT OnSelectionChange (IFileDialog*) override                                            { return S_OK; }
+            JUCE_COMRESULT OnShareViolation (IFileDialog*, IShellItem*, FDE_SHAREVIOLATION_RESPONSE*) override  { return S_OK; }
+            JUCE_COMRESULT OnOverwrite (IFileDialog*, IShellItem*, FDE_OVERWRITE_RESPONSE*) override            { return S_OK; }
+
+            Win32NativeFileChooser& owner;
+        };
+
+        DWORD cookie = 0;
+        dialog.Advise (new Events { *this }, &cookie);
+
+        {
+            ScopedLock lock (deletingDialog);
+
+            if (shouldCancel)
+                return false;
+        }
+
+        const auto result = dialog.Show (async ? nullptr : static_cast<HWND> (owner->getWindowHandle())) == S_OK;
+
+        ScopedLock lock (deletingDialog);
+        nativeDialogRef = nullptr;
+
+        return result;
     }
 
     //==============================================================================
@@ -447,33 +476,21 @@ private:
 
     void run() override
     {
-        // We use a functor rather than a lambda here because
-        // we want to move ownership of the Ptr into the function
-        // object, and C++11 doesn't support general lambda capture
-        struct AsyncCallback
-        {
-            AsyncCallback (Ptr p, Array<URL> r)
-                : ptr (std::move (p)),
-                  results (std::move (r)) {}
+        // IUnknown_GetWindow will only succeed when instantiated in a single-thread apartment
+        CoInitializeEx (nullptr, COINIT_APARTMENTTHREADED);
 
-            void operator()()
-            {
-                ptr->results = std::move (results);
-
-                if (ptr->owner != nullptr)
-                    ptr->owner->exitModalState (ptr->results.size() > 0 ? 1 : 0);
-            }
+        auto resultsCopy = openDialog (true);
+        auto safeOwner = owner;
+        std::weak_ptr<Win32NativeFileChooser> weakThis = shared_from_this();
 
-            Ptr ptr;
-            Array<URL> results;
-        };
-
-        // as long as the thread is running, don't delete this class
-        Ptr safeThis (this);
-        threadHasReference.signal();
+        MessageManager::callAsync ([resultsCopy, safeOwner, weakThis]
+        {
+            if (auto locked = weakThis.lock())
+                locked->results = resultsCopy;
 
-        auto r = openDialog (true);
-        MessageManager::callAsync (AsyncCallback (std::move (safeThis), std::move (r)));
+            if (safeOwner != nullptr)
+                safeOwner->exitModalState (resultsCopy.size() > 0 ? 1 : 0);
+        });
     }
 
     static HashMap<HWND, Win32NativeFileChooser*>& getNativeDialogList()
@@ -482,9 +499,9 @@ private:
         return dialogs;
     }
 
-    static Win32NativeFileChooser* getNativePointerForDialog (HWND hWnd)
+    static Win32NativeFileChooser* getNativePointerForDialog (HWND hwnd)
     {
-        return getNativeDialogList()[hWnd];
+        return getNativeDialogList()[hwnd];
     }
 
     //==============================================================================
@@ -552,7 +569,7 @@ private:
         ScopedLock lock (deletingDialog);
         getNativeDialogList().set (hdlg, this);
 
-        if (shouldCancel.get() != 0)
+        if (shouldCancel)
         {
             EndDialog (hdlg, 0);
         }
@@ -617,7 +634,7 @@ private:
     {
         ScopedLock lock (deletingDialog);
 
-        if (customComponent != nullptr && shouldCancel.get() == 0)
+        if (customComponent != nullptr && ! shouldCancel)
         {
             if (FilePreviewComponent* comp = dynamic_cast<FilePreviewComponent*> (customComponent->getChildComponent (0)))
             {
@@ -715,14 +732,15 @@ private:
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Win32NativeFileChooser)
 };
 
-class FileChooser::Native     : public Component,
+class FileChooser::Native     : public std::enable_shared_from_this<Native>,
+                                public Component,
                                 public FileChooser::Pimpl
 {
 public:
     Native (FileChooser& fileChooser, int flags, FilePreviewComponent* previewComp)
         : owner (fileChooser),
-          nativeFileChooser (new Win32NativeFileChooser (this, flags, previewComp, fileChooser.startingFile,
-                                                         fileChooser.title, fileChooser.filters))
+          nativeFileChooser (std::make_shared<Win32NativeFileChooser> (this, flags, previewComp, fileChooser.startingFile,
+                                                                       fileChooser.title, fileChooser.filters))
     {
         auto mainMon = Desktop::getInstance().getDisplays().getPrimaryDisplay()->userArea;
 
@@ -739,19 +757,17 @@ public:
     {
         exitModalState (0);
         nativeFileChooser->cancel();
-        nativeFileChooser = nullptr;
     }
 
     void launch() override
     {
-        SafePointer<Native> safeThis (this);
+        std::weak_ptr<Native> safeThis = shared_from_this();
 
-        enterModalState (true, ModalCallbackFunction::create (
-                         [safeThis] (int)
-                         {
-                             if (safeThis != nullptr)
-                                 safeThis->owner.finished (safeThis->nativeFileChooser->results);
-                         }));
+        enterModalState (true, ModalCallbackFunction::create ([safeThis] (int)
+        {
+            if (auto locked = safeThis.lock())
+                locked->owner.finished (locked->nativeFileChooser->results);
+        }));
 
         nativeFileChooser->open (true);
     }
@@ -783,7 +799,7 @@ public:
 
 private:
     FileChooser& owner;
-    Win32NativeFileChooser::Ptr nativeFileChooser;
+    std::shared_ptr<Win32NativeFileChooser> nativeFileChooser;
 };
 
 //==============================================================================
@@ -796,10 +812,10 @@ bool FileChooser::isPlatformDialogAvailable()
    #endif
 }
 
-FileChooser::Pimpl* FileChooser::showPlatformDialog (FileChooser& owner, int flags,
-                                                     FilePreviewComponent* preview)
+std::unique_ptr<FileChooser::Pimpl> FileChooser::showPlatformDialog (FileChooser& owner, int flags,
+                                                                     FilePreviewComponent* preview)
 {
-    return new FileChooser::Native (owner, flags, preview);
+    return std::make_unique<FileChooser::Native> (owner, flags, preview);
 }
 
 } // namespace juce