michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "mozilla/Types.h"
michael@0: 
michael@0: #include <gtk/gtk.h>
michael@0: 
michael@0: #include "nsGtkUtils.h"
michael@0: #include "nsIFileURL.h"
michael@0: #include "nsIURI.h"
michael@0: #include "nsIWidget.h"
michael@0: #include "nsIFile.h"
michael@0: #include "nsIStringBundle.h"
michael@0: 
michael@0: #include "nsArrayEnumerator.h"
michael@0: #include "nsMemory.h"
michael@0: #include "nsEnumeratorUtils.h"
michael@0: #include "nsNetUtil.h"
michael@0: #include "nsReadableUtils.h"
michael@0: #include "mozcontainer.h"
michael@0: 
michael@0: #include "nsFilePicker.h"
michael@0: 
michael@0: using namespace mozilla;
michael@0: 
michael@0: #define MAX_PREVIEW_SIZE 180
michael@0: 
michael@0: nsIFile *nsFilePicker::mPrevDisplayDirectory = nullptr;
michael@0: 
michael@0: void
michael@0: nsFilePicker::Shutdown()
michael@0: {
michael@0:   NS_IF_RELEASE(mPrevDisplayDirectory);
michael@0: }
michael@0: 
michael@0: static GtkFileChooserAction
michael@0: GetGtkFileChooserAction(int16_t aMode)
michael@0: {
michael@0:   GtkFileChooserAction action;
michael@0: 
michael@0:   switch (aMode) {
michael@0:     case nsIFilePicker::modeSave:
michael@0:     action = GTK_FILE_CHOOSER_ACTION_SAVE;
michael@0:     break;
michael@0: 
michael@0:     case nsIFilePicker::modeGetFolder:
michael@0:     action = GTK_FILE_CHOOSER_ACTION_SELECT_FOLDER;
michael@0:     break;
michael@0: 
michael@0:     case nsIFilePicker::modeOpen:
michael@0:     case nsIFilePicker::modeOpenMultiple:
michael@0:     action = GTK_FILE_CHOOSER_ACTION_OPEN;
michael@0:     break;
michael@0: 
michael@0:     default:
michael@0:     NS_WARNING("Unknown nsIFilePicker mode");
michael@0:     action = GTK_FILE_CHOOSER_ACTION_OPEN;
michael@0:     break;
michael@0:   }
michael@0: 
michael@0:   return action;
michael@0: }
michael@0: 
michael@0: 
michael@0: static void
michael@0: UpdateFilePreviewWidget(GtkFileChooser *file_chooser,
michael@0:                         gpointer preview_widget_voidptr)
michael@0: {
michael@0:   GtkImage *preview_widget = GTK_IMAGE(preview_widget_voidptr);
michael@0:   char *image_filename = gtk_file_chooser_get_preview_filename(file_chooser);
michael@0: 
michael@0:   if (!image_filename) {
michael@0:     gtk_file_chooser_set_preview_widget_active(file_chooser, FALSE);
michael@0:     return;
michael@0:   }
michael@0: 
michael@0:   gint preview_width = 0;
michael@0:   gint preview_height = 0;
michael@0:   GdkPixbufFormat *preview_format = gdk_pixbuf_get_file_info(image_filename,
michael@0:                                                              &preview_width,
michael@0:                                                              &preview_height);
michael@0:   if (!preview_format) {
michael@0:     g_free(image_filename);
michael@0:     gtk_file_chooser_set_preview_widget_active(file_chooser, FALSE);
michael@0:     return;
michael@0:   }
michael@0: 
michael@0:   GdkPixbuf *preview_pixbuf;
michael@0:   // Only scale down images that are too big
michael@0:   if (preview_width > MAX_PREVIEW_SIZE || preview_height > MAX_PREVIEW_SIZE) {
michael@0:     preview_pixbuf = gdk_pixbuf_new_from_file_at_size(image_filename,
michael@0:                                                       MAX_PREVIEW_SIZE,
michael@0:                                                       MAX_PREVIEW_SIZE,
michael@0:                                                       nullptr);
michael@0:   }
michael@0:   else {
michael@0:     preview_pixbuf = gdk_pixbuf_new_from_file(image_filename, nullptr);
michael@0:   }
michael@0: 
michael@0:   g_free(image_filename);
michael@0: 
michael@0:   if (!preview_pixbuf) {
michael@0:     gtk_file_chooser_set_preview_widget_active(file_chooser, FALSE);
michael@0:     return;
michael@0:   }
michael@0: 
michael@0: #if GTK_CHECK_VERSION(2,12,0)
michael@0:   GdkPixbuf *preview_pixbuf_temp = preview_pixbuf;
michael@0:   preview_pixbuf = gdk_pixbuf_apply_embedded_orientation(preview_pixbuf_temp);
michael@0:   g_object_unref(preview_pixbuf_temp);
michael@0: #endif
michael@0: 
michael@0:   // This is the easiest way to do center alignment without worrying about containers
michael@0:   // Minimum 3px padding each side (hence the 6) just to make things nice
michael@0:   gint x_padding = (MAX_PREVIEW_SIZE + 6 - gdk_pixbuf_get_width(preview_pixbuf)) / 2;
michael@0:   gtk_misc_set_padding(GTK_MISC(preview_widget), x_padding, 0);
michael@0: 
michael@0:   gtk_image_set_from_pixbuf(preview_widget, preview_pixbuf);
michael@0:   g_object_unref(preview_pixbuf);
michael@0:   gtk_file_chooser_set_preview_widget_active(file_chooser, TRUE);
michael@0: }
michael@0: 
michael@0: static nsAutoCString
michael@0: MakeCaseInsensitiveShellGlob(const char* aPattern) {
michael@0:   // aPattern is UTF8
michael@0:   nsAutoCString result;
michael@0:   unsigned int len = strlen(aPattern);
michael@0: 
michael@0:   for (unsigned int i = 0; i < len; i++) {
michael@0:     if (!g_ascii_isalpha(aPattern[i])) {
michael@0:       // non-ASCII characters will also trigger this path, so unicode
michael@0:       // is safely handled albeit case-sensitively
michael@0:       result.Append(aPattern[i]);
michael@0:       continue;
michael@0:     }
michael@0: 
michael@0:     // add the lowercase and uppercase version of a character to a bracket
michael@0:     // match, so it matches either the lowercase or uppercase char.
michael@0:     result.Append('[');
michael@0:     result.Append(g_ascii_tolower(aPattern[i]));
michael@0:     result.Append(g_ascii_toupper(aPattern[i]));
michael@0:     result.Append(']');
michael@0: 
michael@0:   }
michael@0: 
michael@0:   return result;
michael@0: }
michael@0: 
michael@0: NS_IMPL_ISUPPORTS(nsFilePicker, nsIFilePicker)
michael@0: 
michael@0: nsFilePicker::nsFilePicker()
michael@0:   : mSelectedType(0),
michael@0:     mRunning(false),
michael@0:     mAllowURLs(false)
michael@0: {
michael@0: }
michael@0: 
michael@0: nsFilePicker::~nsFilePicker()
michael@0: {
michael@0: }
michael@0: 
michael@0: void
michael@0: ReadMultipleFiles(gpointer filename, gpointer array)
michael@0: {
michael@0:   nsCOMPtr<nsIFile> localfile;
michael@0:   nsresult rv = NS_NewNativeLocalFile(nsDependentCString(static_cast<char*>(filename)),
michael@0:                                       false,
michael@0:                                       getter_AddRefs(localfile));
michael@0:   if (NS_SUCCEEDED(rv)) {
michael@0:     nsCOMArray<nsIFile>& files = *static_cast<nsCOMArray<nsIFile>*>(array);
michael@0:     files.AppendObject(localfile);
michael@0:   }
michael@0: 
michael@0:   g_free(filename);
michael@0: }
michael@0: 
michael@0: void
michael@0: nsFilePicker::ReadValuesFromFileChooser(GtkWidget *file_chooser)
michael@0: {
michael@0:   mFiles.Clear();
michael@0: 
michael@0:   if (mMode == nsIFilePicker::modeOpenMultiple) {
michael@0:     mFileURL.Truncate();
michael@0: 
michael@0:     GSList *list = gtk_file_chooser_get_filenames(GTK_FILE_CHOOSER(file_chooser));
michael@0:     g_slist_foreach(list, ReadMultipleFiles, static_cast<gpointer>(&mFiles));
michael@0:     g_slist_free(list);
michael@0:   } else {
michael@0:     gchar *filename = gtk_file_chooser_get_uri(GTK_FILE_CHOOSER(file_chooser));
michael@0:     mFileURL.Assign(filename);
michael@0:     g_free(filename);
michael@0:   }
michael@0: 
michael@0:   GtkFileFilter *filter = gtk_file_chooser_get_filter(GTK_FILE_CHOOSER(file_chooser));
michael@0:   GSList *filter_list = gtk_file_chooser_list_filters(GTK_FILE_CHOOSER(file_chooser));
michael@0: 
michael@0:   mSelectedType = static_cast<int16_t>(g_slist_index(filter_list, filter));
michael@0:   g_slist_free(filter_list);
michael@0: 
michael@0:   // Remember last used directory.
michael@0:   nsCOMPtr<nsIFile> file;
michael@0:   GetFile(getter_AddRefs(file));
michael@0:   if (file) {
michael@0:     nsCOMPtr<nsIFile> dir;
michael@0:     file->GetParent(getter_AddRefs(dir));
michael@0:     if (dir) {
michael@0:       dir.swap(mPrevDisplayDirectory);
michael@0:     }
michael@0:   }
michael@0: }
michael@0: 
michael@0: void
michael@0: nsFilePicker::InitNative(nsIWidget *aParent,
michael@0:                          const nsAString& aTitle)
michael@0: {
michael@0:   mParentWidget = aParent;
michael@0:   mTitle.Assign(aTitle);
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsFilePicker::AppendFilters(int32_t aFilterMask)
michael@0: {
michael@0:   mAllowURLs = !!(aFilterMask & filterAllowURLs);
michael@0:   return nsBaseFilePicker::AppendFilters(aFilterMask);
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsFilePicker::AppendFilter(const nsAString& aTitle, const nsAString& aFilter)
michael@0: {
michael@0:   if (aFilter.EqualsLiteral("..apps")) {
michael@0:     // No platform specific thing we can do here, really....
michael@0:     return NS_OK;
michael@0:   }
michael@0: 
michael@0:   nsAutoCString filter, name;
michael@0:   CopyUTF16toUTF8(aFilter, filter);
michael@0:   CopyUTF16toUTF8(aTitle, name);
michael@0: 
michael@0:   mFilters.AppendElement(filter);
michael@0:   mFilterNames.AppendElement(name);
michael@0: 
michael@0:   return NS_OK;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsFilePicker::SetDefaultString(const nsAString& aString)
michael@0: {
michael@0:   mDefault = aString;
michael@0: 
michael@0:   return NS_OK;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsFilePicker::GetDefaultString(nsAString& aString)
michael@0: {
michael@0:   // Per API...
michael@0:   return NS_ERROR_FAILURE;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsFilePicker::SetDefaultExtension(const nsAString& aExtension)
michael@0: {
michael@0:   mDefaultExtension = aExtension;
michael@0: 
michael@0:   return NS_OK;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsFilePicker::GetDefaultExtension(nsAString& aExtension)
michael@0: {
michael@0:   aExtension = mDefaultExtension;
michael@0: 
michael@0:   return NS_OK;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsFilePicker::GetFilterIndex(int32_t *aFilterIndex)
michael@0: {
michael@0:   *aFilterIndex = mSelectedType;
michael@0: 
michael@0:   return NS_OK;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsFilePicker::SetFilterIndex(int32_t aFilterIndex)
michael@0: {
michael@0:   mSelectedType = aFilterIndex;
michael@0: 
michael@0:   return NS_OK;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsFilePicker::GetFile(nsIFile **aFile)
michael@0: {
michael@0:   NS_ENSURE_ARG_POINTER(aFile);
michael@0: 
michael@0:   *aFile = nullptr;
michael@0:   nsCOMPtr<nsIURI> uri;
michael@0:   nsresult rv = GetFileURL(getter_AddRefs(uri));
michael@0:   if (!uri)
michael@0:     return rv;
michael@0: 
michael@0:   nsCOMPtr<nsIFileURL> fileURL(do_QueryInterface(uri, &rv));
michael@0:   NS_ENSURE_SUCCESS(rv, rv);
michael@0: 
michael@0:   nsCOMPtr<nsIFile> file;
michael@0:   rv = fileURL->GetFile(getter_AddRefs(file));
michael@0:   NS_ENSURE_SUCCESS(rv, rv);
michael@0: 
michael@0:   file.forget(aFile);
michael@0:   return NS_OK;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsFilePicker::GetFileURL(nsIURI **aFileURL)
michael@0: {
michael@0:   *aFileURL = nullptr;
michael@0:   return NS_NewURI(aFileURL, mFileURL);
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsFilePicker::GetFiles(nsISimpleEnumerator **aFiles)
michael@0: {
michael@0:   NS_ENSURE_ARG_POINTER(aFiles);
michael@0: 
michael@0:   if (mMode == nsIFilePicker::modeOpenMultiple) {
michael@0:     return NS_NewArrayEnumerator(aFiles, mFiles);
michael@0:   }
michael@0: 
michael@0:   return NS_ERROR_FAILURE;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsFilePicker::Show(int16_t *aReturn)
michael@0: {
michael@0:   NS_ENSURE_ARG_POINTER(aReturn);
michael@0: 
michael@0:   nsresult rv = Open(nullptr);
michael@0:   if (NS_FAILED(rv))
michael@0:     return rv;
michael@0: 
michael@0:   while (mRunning) {
michael@0:     g_main_context_iteration(nullptr, TRUE);
michael@0:   }
michael@0: 
michael@0:   *aReturn = mResult;
michael@0:   return NS_OK;
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsFilePicker::Open(nsIFilePickerShownCallback *aCallback)
michael@0: {
michael@0:   // Can't show two dialogs concurrently with the same filepicker
michael@0:   if (mRunning)
michael@0:     return NS_ERROR_NOT_AVAILABLE;
michael@0: 
michael@0:   nsXPIDLCString title;
michael@0:   title.Adopt(ToNewUTF8String(mTitle));
michael@0: 
michael@0:   GtkWindow *parent_widget =
michael@0:     GTK_WINDOW(mParentWidget->GetNativeData(NS_NATIVE_SHELLWIDGET));
michael@0: 
michael@0:   GtkFileChooserAction action = GetGtkFileChooserAction(mMode);
michael@0:   const gchar *accept_button = (action == GTK_FILE_CHOOSER_ACTION_SAVE)
michael@0:                                ? GTK_STOCK_SAVE : GTK_STOCK_OPEN;
michael@0:   GtkWidget *file_chooser =
michael@0:       gtk_file_chooser_dialog_new(title, parent_widget, action,
michael@0:                                   GTK_STOCK_CANCEL, GTK_RESPONSE_CANCEL,
michael@0:                                   accept_button, GTK_RESPONSE_ACCEPT,
michael@0:                                   nullptr);
michael@0:   gtk_dialog_set_alternative_button_order(GTK_DIALOG(file_chooser),
michael@0:                                           GTK_RESPONSE_ACCEPT,
michael@0:                                           GTK_RESPONSE_CANCEL,
michael@0:                                           -1);
michael@0:   if (mAllowURLs) {
michael@0:     gtk_file_chooser_set_local_only(GTK_FILE_CHOOSER(file_chooser), FALSE);
michael@0:   }
michael@0: 
michael@0:   if (action == GTK_FILE_CHOOSER_ACTION_OPEN || action == GTK_FILE_CHOOSER_ACTION_SAVE) {
michael@0:     GtkWidget *img_preview = gtk_image_new();
michael@0:     gtk_file_chooser_set_preview_widget(GTK_FILE_CHOOSER(file_chooser), img_preview);
michael@0:     g_signal_connect(file_chooser, "update-preview", G_CALLBACK(UpdateFilePreviewWidget), img_preview);
michael@0:   }
michael@0: 
michael@0:   GtkWindow *window = GTK_WINDOW(file_chooser);
michael@0:   gtk_window_set_modal(window, TRUE);
michael@0:   if (parent_widget) {
michael@0:     gtk_window_set_destroy_with_parent(window, TRUE);
michael@0:   }
michael@0: 
michael@0:   NS_ConvertUTF16toUTF8 defaultName(mDefault);
michael@0:   switch (mMode) {
michael@0:     case nsIFilePicker::modeOpenMultiple:
michael@0:       gtk_file_chooser_set_select_multiple(GTK_FILE_CHOOSER(file_chooser), TRUE);
michael@0:       break;
michael@0:     case nsIFilePicker::modeSave:
michael@0:       gtk_file_chooser_set_current_name(GTK_FILE_CHOOSER(file_chooser),
michael@0:                                         defaultName.get());
michael@0:       break;
michael@0:   }
michael@0: 
michael@0:   nsCOMPtr<nsIFile> defaultPath;
michael@0:   if (mDisplayDirectory) {
michael@0:     mDisplayDirectory->Clone(getter_AddRefs(defaultPath));
michael@0:   } else if (mPrevDisplayDirectory) {
michael@0:     mPrevDisplayDirectory->Clone(getter_AddRefs(defaultPath));
michael@0:   }
michael@0: 
michael@0:   if (defaultPath) {
michael@0:     if (!defaultName.IsEmpty() && mMode != nsIFilePicker::modeSave) {
michael@0:       // Try to select the intended file. Even if it doesn't exist, GTK still switches
michael@0:       // directories.
michael@0:       defaultPath->AppendNative(defaultName);
michael@0:       nsAutoCString path;
michael@0:       defaultPath->GetNativePath(path);
michael@0:       gtk_file_chooser_set_filename(GTK_FILE_CHOOSER(file_chooser), path.get());
michael@0:     } else {
michael@0:       nsAutoCString directory;
michael@0:       defaultPath->GetNativePath(directory);
michael@0:       gtk_file_chooser_set_current_folder(GTK_FILE_CHOOSER(file_chooser),
michael@0:                                           directory.get());
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   gtk_dialog_set_default_response(GTK_DIALOG(file_chooser), GTK_RESPONSE_ACCEPT);
michael@0: 
michael@0:   int32_t count = mFilters.Length();
michael@0:   for (int32_t i = 0; i < count; ++i) {
michael@0:     // This is fun... the GTK file picker does not accept a list of filters
michael@0:     // so we need to split out each string, and add it manually.
michael@0: 
michael@0:     char **patterns = g_strsplit(mFilters[i].get(), ";", -1);
michael@0:     if (!patterns) {
michael@0:       return NS_ERROR_OUT_OF_MEMORY;
michael@0:     }
michael@0: 
michael@0:     GtkFileFilter *filter = gtk_file_filter_new();
michael@0:     for (int j = 0; patterns[j] != nullptr; ++j) {
michael@0:       nsAutoCString caseInsensitiveFilter = MakeCaseInsensitiveShellGlob(g_strstrip(patterns[j]));
michael@0:       gtk_file_filter_add_pattern(filter, caseInsensitiveFilter.get());
michael@0:     }
michael@0: 
michael@0:     g_strfreev(patterns);
michael@0: 
michael@0:     if (!mFilterNames[i].IsEmpty()) {
michael@0:       // If we have a name for our filter, let's use that.
michael@0:       const char *filter_name = mFilterNames[i].get();
michael@0:       gtk_file_filter_set_name(filter, filter_name);
michael@0:     } else {
michael@0:       // If we don't have a name, let's just use the filter pattern.
michael@0:       const char *filter_pattern = mFilters[i].get();
michael@0:       gtk_file_filter_set_name(filter, filter_pattern);
michael@0:     }
michael@0: 
michael@0:     gtk_file_chooser_add_filter(GTK_FILE_CHOOSER(file_chooser), filter);
michael@0: 
michael@0:     // Set the initially selected filter
michael@0:     if (mSelectedType == i) {
michael@0:       gtk_file_chooser_set_filter(GTK_FILE_CHOOSER(file_chooser), filter);
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   gtk_file_chooser_set_do_overwrite_confirmation(GTK_FILE_CHOOSER(file_chooser), TRUE);
michael@0: 
michael@0:   mRunning = true;
michael@0:   mCallback = aCallback;
michael@0:   NS_ADDREF_THIS();
michael@0:   g_signal_connect(file_chooser, "response", G_CALLBACK(OnResponse), this);
michael@0:   g_signal_connect(file_chooser, "destroy", G_CALLBACK(OnDestroy), this);
michael@0:   gtk_widget_show(file_chooser);
michael@0: 
michael@0:   return NS_OK;
michael@0: }
michael@0: 
michael@0: /* static */ void
michael@0: nsFilePicker::OnResponse(GtkWidget* file_chooser, gint response_id,
michael@0:                          gpointer user_data)
michael@0: {
michael@0:   static_cast<nsFilePicker*>(user_data)->
michael@0:     Done(file_chooser, response_id);
michael@0: }
michael@0: 
michael@0: /* static */ void
michael@0: nsFilePicker::OnDestroy(GtkWidget* file_chooser, gpointer user_data)
michael@0: {
michael@0:   static_cast<nsFilePicker*>(user_data)->
michael@0:     Done(file_chooser, GTK_RESPONSE_CANCEL);
michael@0: }
michael@0: 
michael@0: void
michael@0: nsFilePicker::Done(GtkWidget* file_chooser, gint response)
michael@0: {
michael@0:   mRunning = false;
michael@0: 
michael@0:   int16_t result;
michael@0:   switch (response) {
michael@0:     case GTK_RESPONSE_OK:
michael@0:     case GTK_RESPONSE_ACCEPT:
michael@0:     ReadValuesFromFileChooser(file_chooser);
michael@0:     result = nsIFilePicker::returnOK;
michael@0:     if (mMode == nsIFilePicker::modeSave) {
michael@0:       nsCOMPtr<nsIFile> file;
michael@0:       GetFile(getter_AddRefs(file));
michael@0:       if (file) {
michael@0:         bool exists = false;
michael@0:         file->Exists(&exists);
michael@0:         if (exists)
michael@0:           result = nsIFilePicker::returnReplace;
michael@0:       }
michael@0:     }
michael@0:     break;
michael@0: 
michael@0:     case GTK_RESPONSE_CANCEL:
michael@0:     case GTK_RESPONSE_CLOSE:
michael@0:     case GTK_RESPONSE_DELETE_EVENT:
michael@0:     result = nsIFilePicker::returnCancel;
michael@0:     break;
michael@0: 
michael@0:     default:
michael@0:     NS_WARNING("Unexpected response");
michael@0:     result = nsIFilePicker::returnCancel;
michael@0:     break;
michael@0:   }
michael@0: 
michael@0:   // A "response" signal won't be sent again but "destroy" will be.
michael@0:   g_signal_handlers_disconnect_by_func(file_chooser,
michael@0:                                        FuncToGpointer(OnDestroy), this);
michael@0: 
michael@0:   // When response_id is GTK_RESPONSE_DELETE_EVENT or when called from
michael@0:   // OnDestroy, the widget would be destroyed anyway but it is fine if
michael@0:   // gtk_widget_destroy is called more than once.  gtk_widget_destroy has
michael@0:   // requests that any remaining references be released, but the reference
michael@0:   // count will not be decremented again if GtkWindow's reference has already
michael@0:   // been released.
michael@0:   gtk_widget_destroy(file_chooser);
michael@0: 
michael@0:   if (mCallback) {
michael@0:     mCallback->Done(result);
michael@0:     mCallback = nullptr;
michael@0:   } else {
michael@0:     mResult = result;
michael@0:   }
michael@0:   NS_RELEASE_THIS();
michael@0: }