[xdg-desktop-portal-gnome/gbsneto/more-portals: 1/2] Implement the Print portal

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 2ffa5a9d7b4613e1c10f456c44e368e5ecc1ba5b
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Thu Dec 9 18:25:44 2021 -0300

    Implement the Print portal
    
    Mostly a copy of the xdg-desktop-portal-gtk implementation.

 data/gnome.portal              |   2 +-
 src/meson.build                |   4 +
 src/print.c                    | 719 +++++++++++++++++++++++++++++++++++++++++
 src/print.h                    |  26 ++
 src/xdg-desktop-portal-gnome.c |   7 +
 5 files changed, 757 insertions(+), 1 deletion(-)
---
diff --git a/data/gnome.portal b/data/gnome.portal
index 2502fd9..d47d251 100644
--- a/data/gnome.portal
+++ b/data/gnome.portal
@@ -1,4 +1,4 @@
 [portal]
 DBusName=org.freedesktop.impl.portal.desktop.gnome
-Interfaces=org.freedesktop.impl.portal.AppChooser;org.freedesktop.impl.portal.Screenshot;org.freedesktop.impl.portal.ScreenCast;org.freedesktop.impl.portal.RemoteDesktop;org.freedesktop.impl.portal.Lockdown;org.freedesktop.impl.portal.Background;org.freedesktop.impl.portal.Settings;org.freedesktop.impl.portal.Wallpaper;org.freedesktop.impl.portal.FileChooser;
+Interfaces=org.freedesktop.impl.portal.AppChooser;org.freedesktop.impl.portal.Screenshot;org.freedesktop.impl.portal.ScreenCast;org.freedesktop.impl.portal.RemoteDesktop;org.freedesktop.impl.portal.Lockdown;org.freedesktop.impl.portal.Background;org.freedesktop.impl.portal.Settings;org.freedesktop.impl.portal.Wallpaper;org.freedesktop.impl.portal.FileChooser;org.freedesktop.impl.portal.Print;
 UseIn=gnome
diff --git a/src/meson.build b/src/meson.build
index 0c0a9a5..f26185c 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -6,6 +6,7 @@ xdg_desktop_portal_dep = dependency('xdg-desktop-portal', version: '>= 1.5')
 # Desktop Portal D-Bus interfaces
 desktop_portal_interfaces_dir = xdg_desktop_portal_dep.get_pkgconfig_variable('interfaces_dir')
 desktop_portal_dbus_interfaces = [
+  desktop_portal_interfaces_dir / 'org.freedesktop.impl.portal.Print.xml',
   desktop_portal_interfaces_dir / 'org.freedesktop.impl.portal.Request.xml',
   desktop_portal_interfaces_dir / 'org.freedesktop.impl.portal.Session.xml',
   desktop_portal_interfaces_dir / 'org.freedesktop.impl.portal.AppChooser.xml',
@@ -53,6 +54,7 @@ built_sources += gnome.compile_resources(
 config_h = configuration_data()
 config_h.set_quoted('GETTEXT_PACKAGE', meson.project_name())
 config_h.set_quoted('LOCALEDIR', prefix / get_option('localedir'))
+config_h.set_quoted('PACKAGE_NAME', meson.project_name())
 config_h.set_quoted('PACKAGE_STRING', '@0@ @1@'.format(meson.project_name(), meson.project_version()))
 built_sources += configure_file(output: 'config.h', configuration: config_h)
 
@@ -69,6 +71,7 @@ deps = [
   dependency('glib-2.0', version: '>= 2.44'),
   dependency('gio-unix-2.0'),
   dependency('gtk4', version: '>= 4.0'),
+  dependency('gtk4-unix-print', version: '>= 4.0'),
   dependency('gsettings-desktop-schemas'),
   libadwaita_dep,
   xdg_desktop_portal_dep,
@@ -88,6 +91,7 @@ sources = built_sources + files(
   'gnome-bg-slide-show.c',
   'gnomescreencast.c',
   'lockdown.c',
+  'print.c',
   'remotedesktop.c',
   'remotedesktopdialog.c',
   'request.c',
diff --git a/src/print.c b/src/print.c
new file mode 100644
index 0000000..60722cb
--- /dev/null
+++ b/src/print.c
@@ -0,0 +1,719 @@
+/*
+ * Copyright © 2016 Red Hat, Inc
+ *             2021 Endless OS Foundation LLC
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ *       Matthias Clasen <mclasen redhat com>
+ */
+
+#define _GNU_SOURCE 1
+
+#include "config.h"
+
+#include <string.h>
+
+#include <gtk/gtk.h>
+#include <gtk/gtkunixprint.h>
+
+#include <gio/gio.h>
+#include <gio/gunixfdlist.h>
+#include <gio/gunixinputstream.h>
+#include <gio/gunixoutputstream.h>
+#include <gio/gdesktopappinfo.h>
+
+#include "xdg-desktop-portal-dbus.h"
+
+#include "print.h"
+#include "request.h"
+#include "utils.h"
+#include "externalwindow.h"
+
+typedef struct {
+  char *app_id;
+  GtkPageSetup *page_setup;
+  GtkPrintSettings *settings;
+  GtkPrinter *printer;
+  guint timeout_id;
+  guint32 token;
+  gboolean preview;
+} PrintParams;
+
+static GHashTable *print_params;
+
+static void
+print_params_free (gpointer data)
+{
+  PrintParams *params = data;
+
+  g_hash_table_remove (print_params, GUINT_TO_POINTER (params->token));
+
+  g_free (params->app_id);
+  g_object_unref (params->page_setup);
+  g_object_unref (params->settings);
+  g_object_unref (params->printer);
+
+  g_free (params);
+}
+
+static void
+ensure_print_params (void)
+{
+  if (print_params)
+    return;
+
+  print_params = g_hash_table_new (g_direct_hash, g_direct_equal);
+}
+
+static gboolean
+print_params_timeout (gpointer data)
+{
+  print_params_free (data);
+  g_debug ("Removing print params, now %d", g_hash_table_size (print_params));
+  return G_SOURCE_REMOVE;
+}
+
+static PrintParams *
+print_params_new (const char       *app_id,
+                  gboolean          preview,
+                  GtkPageSetup     *page_setup,
+                  GtkPrintSettings *settings,
+                  GtkPrinter       *printer)
+{
+  PrintParams *params;
+  guint32 r;
+
+  ensure_print_params ();
+
+  params = g_new0 (PrintParams, 1);
+  params->app_id = g_strdup (app_id);
+  params->page_setup = g_object_ref (page_setup);
+  params->settings = g_object_ref (settings);
+  params->printer = g_object_ref (printer);
+  params->preview = preview;
+
+  do {
+    r = g_random_int ();
+  } while (r == 0 || g_hash_table_lookup (print_params, GUINT_TO_POINTER (r)) != NULL);
+
+  params->token = r;
+  g_hash_table_insert (print_params, GUINT_TO_POINTER (r), params);
+
+  g_debug ("Remembering print params for %s, token %u, now %d",
+           params->app_id, params->token,
+           g_hash_table_size (print_params));
+
+  params->timeout_id = g_timeout_add_seconds (300, print_params_timeout, params);
+
+  return params;
+}
+
+static PrintParams *
+get_print_params (const char *app_id,
+                  guint32     token)
+{
+  PrintParams *params;
+
+  params = (PrintParams *)g_hash_table_lookup (print_params, GUINT_TO_POINTER (token));
+  if (params == NULL)
+    return NULL;
+
+  if (strcmp (params->app_id, app_id) != 0)
+    return NULL;
+
+  g_source_remove (params->timeout_id);
+  g_hash_table_remove (print_params, GUINT_TO_POINTER (token));
+
+  return params;
+}
+
+typedef struct {
+  XdpImplPrint *impl;
+  GDBusMethodInvocation *invocation;
+  Request *request;
+  GtkWidget *dialog;
+  ExternalWindow *external_parent;
+
+  int fd;
+  int response;
+
+  PrintParams *params;
+
+} PrintDialogHandle;
+
+static void
+print_dialog_handle_free (gpointer data)
+{
+  PrintDialogHandle *handle = data;
+
+  g_clear_object (&handle->external_parent);
+  g_object_unref (handle->request);
+  g_object_unref (handle->dialog);
+  close (handle->fd);
+
+  g_free (handle);
+}
+
+static void
+print_dialog_handle_close (PrintDialogHandle *handle)
+{
+  gtk_window_destroy (GTK_WINDOW (handle->dialog));
+  print_dialog_handle_free (handle);
+}
+
+static gboolean
+can_preview (void)
+{
+  g_autofree char *path = NULL;
+
+  path = g_find_program_in_path ("evince-previewer");
+
+  if (path)
+    return TRUE;
+
+  g_warning ("evince-previewer not found, disabling print preview");
+
+  return FALSE;
+}
+
+static gboolean
+launch_preview (const char        *filename,
+                const char        *title,
+                GtkPrintSettings  *settings,
+                GtkPageSetup      *page_setup,
+                GError           **error)
+{
+  g_autofree char *cmd = NULL;
+  g_autoptr(GAppInfo) appinfo = NULL;
+  g_autoptr(GAppLaunchContext) context = NULL;
+  gboolean retval = FALSE;
+  g_autoptr(GKeyFile) keyfile = NULL;
+  g_autofree char *data = NULL;
+  gsize data_len;
+  g_autofree char *settings_filename = NULL;
+  int fd;
+
+  fd = g_file_open_tmp ("settingsXXXXXX.ini", &settings_filename, error);
+  if (fd == -1)
+    goto out;
+
+  keyfile = g_key_file_new ();
+
+  if (settings)
+    gtk_print_settings_to_key_file (settings, keyfile, NULL);
+
+  if (page_setup)
+    gtk_page_setup_to_key_file (page_setup, keyfile, NULL);
+
+  g_key_file_set_string (keyfile, "Print Job", "title", title);
+
+  data = g_key_file_to_data (keyfile, &data_len, NULL);
+  if (data)
+    g_file_set_contents (settings_filename, data, data_len, NULL);
+
+  cmd = g_strdup_printf ("evince-previewer --unlink-tempfile --print-settings %s %s", settings_filename, 
filename);
+
+  g_debug ("launching %s", cmd);
+
+  appinfo = g_app_info_create_from_commandline (cmd,
+                                                "Print Preview",
+                                                G_APP_INFO_CREATE_NONE,
+                                                error);
+  if (!appinfo)
+    goto out;
+
+  context = (GAppLaunchContext *)gdk_display_get_app_launch_context (gdk_display_get_default ());
+  retval = g_app_info_launch (appinfo, NULL, G_APP_LAUNCH_CONTEXT (context), error);
+
+out:
+  if (fd > 0)
+    close (fd);
+
+  return retval;
+}
+
+static gboolean
+print_file (int                fd,
+            const char        *app_id,
+            gboolean           preview,
+            GtkPrinter        *printer,
+            GtkPrintSettings  *settings,
+            GtkPageSetup      *page_setup,
+            GError           **error)
+{
+  g_autoptr (GtkPrintJob) job = NULL;
+  g_autofree char *title = NULL;
+  g_autofree char *filename = NULL;
+  g_autoptr(GUnixInputStream) istream = NULL;
+  g_autoptr(GUnixOutputStream) ostream = NULL;
+  int fd2;
+  g_autofree char *app_desktop_fullname = NULL;
+  g_autoptr (GDesktopAppInfo) app_info = NULL;
+  // ensures the app_name won't be NULL even if the app_id.desktop file doesn't exist
+  g_autofree char *app_name = g_strdup (app_id);
+
+  if (!g_str_has_suffix (app_id, ".desktop"))
+    {
+      app_desktop_fullname = g_strconcat (app_id, ".desktop", NULL);
+    }
+  else
+    {
+      app_desktop_fullname = g_strdup (app_id);
+    }
+
+  app_info = g_desktop_app_info_new (app_desktop_fullname);
+  if (app_info)
+    {
+      app_name = g_desktop_app_info_get_locale_string (app_info, "Name");
+    }
+
+  title = g_strdup_printf ("Document from %s", app_name);
+
+  if (!preview)
+    job = gtk_print_job_new (title, printer, settings, page_setup);
+
+#if GTK_CHECK_VERSION (3, 22, 0)
+  if (job && !gtk_print_job_set_source_fd (job, fd, error))
+    return FALSE;
+#endif
+
+  istream = (GUnixInputStream *)g_unix_input_stream_new (fd, FALSE);
+
+  if ((fd2 = g_file_open_tmp (PACKAGE_NAME "XXXXXX", &filename, error)) == -1)
+    return FALSE;
+
+  ostream = (GUnixOutputStream *)g_unix_output_stream_new (fd2, TRUE);
+
+  if (g_output_stream_splice (G_OUTPUT_STREAM (ostream),
+                              G_INPUT_STREAM (istream),
+                              G_OUTPUT_STREAM_SPLICE_NONE,
+                              NULL,
+                              error) == -1)
+    return FALSE;
+  if (job)
+    {
+      if (!gtk_print_job_set_source_file (job, filename, error))
+        return FALSE;
+
+      gtk_print_job_send (job, NULL, NULL, NULL);
+    }
+  else
+    {
+      if (!launch_preview (filename, title, settings, page_setup, error))
+        {
+          unlink (filename);
+          return FALSE;
+        }
+    }
+
+  /* The file will be removed when the GtkPrintJob closes it (once the job is
+   * complete).
+   */
+  if (!preview)
+    unlink (filename);
+
+  return TRUE;
+}
+
+static void
+handle_print_response (GtkDialog *dialog,
+                       gint       response,
+                       gpointer   data)
+{
+  PrintDialogHandle *handle = data;
+  g_autoptr(GError) error = NULL;
+  gboolean preview = FALSE;
+
+  switch (response)
+    {
+    default:
+      g_warning ("Unexpected response: %d", response);
+      /* Fall through */
+    case GTK_RESPONSE_DELETE_EVENT:
+      handle->response = 2;
+      break;
+
+    case GTK_RESPONSE_CANCEL:
+      handle->response = 1;
+      break;
+
+    case GTK_RESPONSE_APPLY:
+      preview = TRUE;
+      /* fall thru */
+
+    case GTK_RESPONSE_OK:
+      {
+        GtkPrinter *printer;
+        GtkPrintSettings *settings;
+        GtkPageSetup *page_setup;
+
+        printer = gtk_print_unix_dialog_get_selected_printer (GTK_PRINT_UNIX_DIALOG (handle->dialog));
+        settings = gtk_print_unix_dialog_get_settings (GTK_PRINT_UNIX_DIALOG (handle->dialog));
+        page_setup = gtk_print_unix_dialog_get_page_setup (GTK_PRINT_UNIX_DIALOG (handle->dialog));
+
+        if (!print_file (handle->fd,
+                         handle->request->app_id,
+                         preview,
+                         printer,
+                         settings,
+                         page_setup,
+                         &error))
+          handle->response = 2;
+        else
+          handle->response = 0;
+
+        g_object_unref (settings);
+      }
+      break;
+    }
+
+  if (handle->request->exported)
+    request_unexport (handle->request);
+
+  if (error)
+    {
+      g_dbus_method_invocation_take_error (handle->invocation, error);
+    }
+  else
+    {
+      GVariantBuilder opt_builder;
+
+      g_variant_builder_init (&opt_builder, G_VARIANT_TYPE_VARDICT);
+      xdp_impl_print_complete_print (handle->impl,
+                                     handle->invocation,
+                                     NULL,
+                                     handle->response,
+                                     g_variant_builder_end (&opt_builder));
+    }
+
+  print_dialog_handle_close (handle);
+}
+
+static gboolean
+handle_close (XdpImplRequest        *object,
+              GDBusMethodInvocation *invocation,
+              PrintDialogHandle     *handle)
+{
+  GVariantBuilder opt_builder;
+
+  g_variant_builder_init (&opt_builder, G_VARIANT_TYPE_VARDICT);
+  xdp_impl_print_complete_print (handle->impl,
+                                 handle->invocation,
+                                 NULL,
+                                 2,
+                                 g_variant_builder_end (&opt_builder));
+  print_dialog_handle_close (handle);
+
+  if (handle->request->exported)
+    request_unexport (handle->request);
+
+  xdp_impl_request_complete_close (object, invocation);
+
+  return TRUE;
+}
+
+static gboolean
+handle_print (XdpImplPrint          *object,
+              GDBusMethodInvocation *invocation,
+              GUnixFDList           *fd_list,
+              const char            *arg_handle,
+              const char            *arg_app_id,
+              const char            *arg_parent_window,
+              const char            *arg_title,
+              GVariant              *arg_fd_in,
+              GVariant              *arg_options)
+{
+  g_autoptr(Request) request = NULL;
+  const char *sender;
+  GtkWidget *dialog;
+  PrintDialogHandle *handle;
+  guint32 token = 0;
+  PrintParams *params;
+  int idx, fd;
+  gboolean modal;
+  GdkDisplay *display;
+  GdkSurface *surface;
+  ExternalWindow *external_parent = NULL;
+  GtkWidget *fake_parent;
+
+  g_variant_get (arg_fd_in, "h", &idx);
+  fd = g_unix_fd_list_get (fd_list, idx, NULL);
+
+  g_variant_lookup (arg_options, "token", "u", &token);
+  params = get_print_params (arg_app_id, token);
+  if (params)
+    {
+      GVariantBuilder opt_builder;
+
+      print_file (fd,
+                  params->app_id,
+                  params->preview,
+                  params->printer,
+                  params->settings,
+                  params->page_setup,
+                  NULL);
+
+      print_params_free (params);
+
+      g_variant_builder_init (&opt_builder, G_VARIANT_TYPE_VARDICT);
+      xdp_impl_print_complete_print (object,
+                                     invocation,
+                                     NULL,
+                                     0,
+                                     g_variant_builder_end (&opt_builder));
+      return TRUE;
+    }
+
+  sender = g_dbus_method_invocation_get_sender (invocation);
+  request = request_new (sender, arg_app_id, arg_handle);
+
+  if (arg_parent_window)
+    {
+      external_parent = create_external_window_from_handle (arg_parent_window);
+      if (!external_parent)
+        g_warning ("Failed to associate portal window with parent window %s",
+                   arg_parent_window);
+    }
+
+  if (external_parent)
+    display = external_window_get_display (external_parent);
+  else
+    display = gdk_display_get_default ();
+
+  fake_parent = g_object_new (GTK_TYPE_WINDOW,
+                              "display", display,
+                              NULL);
+  g_object_ref_sink (fake_parent);
+
+
+  if (!g_variant_lookup (arg_options, "modal", "b", &modal))
+    modal = TRUE;
+
+  dialog = gtk_print_unix_dialog_new (arg_title, NULL);
+  gtk_window_set_transient_for (GTK_WINDOW (dialog), GTK_WINDOW (fake_parent));
+  gtk_window_set_modal (GTK_WINDOW (dialog), modal);
+  gtk_print_unix_dialog_set_manual_capabilities (GTK_PRINT_UNIX_DIALOG (dialog),
+                                                 can_preview () ? GTK_PRINT_CAPABILITY_PREVIEW : 0 |
+                                                 GTK_PRINT_CAPABILITY_PAGE_SET |
+                                                 GTK_PRINT_CAPABILITY_COPIES |
+                                                 GTK_PRINT_CAPABILITY_COLLATE |
+                                                 GTK_PRINT_CAPABILITY_REVERSE |
+                                                 GTK_PRINT_CAPABILITY_SCALE |
+                                                 GTK_PRINT_CAPABILITY_NUMBER_UP
+                                                 );
+  handle = g_new0 (PrintDialogHandle, 1);
+  handle->impl = object;
+  handle->invocation = invocation;
+  handle->request = g_object_ref (request);
+  handle->dialog = g_object_ref (dialog);
+  handle->external_parent = external_parent;
+  handle->fd = fd;
+
+  g_signal_connect (request, "handle-close", G_CALLBACK (handle_close), handle);
+
+  g_signal_connect (dialog, "response", G_CALLBACK (handle_print_response), handle);
+
+  gtk_widget_realize (dialog);
+
+  surface = gtk_native_get_surface (GTK_NATIVE (dialog));
+  if (external_parent)
+    external_window_set_parent_of (external_parent, surface);
+
+  request_export (request, g_dbus_method_invocation_get_connection (invocation));
+
+  gtk_window_present (GTK_WINDOW (dialog));
+
+  return TRUE;
+}
+
+static void
+send_prepare_print_response (PrintDialogHandle *handle)
+{
+  GVariantBuilder opt_builder;
+
+  g_variant_builder_init (&opt_builder, G_VARIANT_TYPE_VARDICT);
+
+  if (handle->response == 0)
+    {
+      g_variant_builder_add (&opt_builder, "{sv}", "settings", gtk_print_settings_to_gvariant 
(handle->params->settings));
+      g_variant_builder_add (&opt_builder, "{sv}", "page-setup", gtk_page_setup_to_gvariant 
(handle->params->page_setup));
+      g_variant_builder_add (&opt_builder, "{sv}", "token", g_variant_new_uint32 (handle->params->token));
+    }
+
+  if (handle->request->exported)
+    request_unexport (handle->request);
+
+  xdp_impl_print_complete_prepare_print (handle->impl,
+                                         handle->invocation,
+                                         handle->response,
+                                         g_variant_builder_end (&opt_builder));
+
+  print_dialog_handle_close (handle);
+}
+
+static void
+handle_prepare_print_response (GtkDialog *dialog,
+                               gint       response,
+                               gpointer   data)
+{
+  PrintDialogHandle *handle = data;
+  gboolean preview = FALSE;
+
+  switch (response)
+    {
+    default:
+      g_warning ("Unexpected response: %d", response);
+      /* Fall through */
+    case GTK_RESPONSE_DELETE_EVENT:
+      handle->response = 2;
+      break;
+
+    case GTK_RESPONSE_CANCEL:
+      handle->response = 1;
+      break;
+
+    case GTK_RESPONSE_APPLY:
+      preview = TRUE;
+      /* fall thru */
+
+    case GTK_RESPONSE_OK:
+      {
+        handle->response = 0;
+
+        handle->params = print_params_new (handle->request->app_id,
+                                           preview,
+                                           gtk_print_unix_dialog_get_page_setup (GTK_PRINT_UNIX_DIALOG 
(handle->dialog)),
+                                           gtk_print_unix_dialog_get_settings (GTK_PRINT_UNIX_DIALOG 
(handle->dialog)),
+                                           gtk_print_unix_dialog_get_selected_printer (GTK_PRINT_UNIX_DIALOG 
(handle->dialog)));
+      }
+      break;
+    }
+
+  send_prepare_print_response (handle);
+}
+
+static gboolean
+handle_prepare_print (XdpImplPrint          *object,
+                      GDBusMethodInvocation *invocation,
+                      const char            *arg_handle,
+                      const char            *arg_app_id,
+                      const char            *arg_parent_window,
+                      const char            *arg_title,
+                      GVariant              *arg_settings,
+                      GVariant              *arg_page_setup,
+                      GVariant              *arg_options)
+{
+  g_autoptr(Request) request = NULL;
+  const char *sender;
+  GtkWidget *dialog;
+  PrintDialogHandle *handle;
+  GtkPrintSettings *settings;
+  GtkPageSetup *page_setup;
+  gboolean modal;
+  GdkDisplay *display;
+  GdkSurface *surface;
+  ExternalWindow *external_parent = NULL;
+  GtkWidget *fake_parent;
+
+  sender = g_dbus_method_invocation_get_sender (invocation);
+
+  request = request_new (sender, arg_app_id, arg_handle);
+
+  if (arg_parent_window)
+    {
+      external_parent = create_external_window_from_handle (arg_parent_window);
+      if (!external_parent)
+        g_warning ("Failed to associate portal window with parent window %s",
+                   arg_parent_window);
+    }
+
+  if (external_parent)
+    display = external_window_get_display (external_parent);
+  else
+    display = gdk_display_get_default ();
+
+  fake_parent = g_object_new (GTK_TYPE_WINDOW,
+                              "display", display,
+                              NULL);
+  g_object_ref_sink (fake_parent);
+
+  settings = gtk_print_settings_new_from_gvariant (arg_settings);
+  page_setup = gtk_page_setup_new_from_gvariant (arg_page_setup);
+  if (!g_variant_lookup (arg_options, "modal", "b", &modal))
+    modal = TRUE;
+
+  dialog = gtk_print_unix_dialog_new (arg_title, NULL);
+  gtk_window_set_transient_for (GTK_WINDOW (dialog), GTK_WINDOW (fake_parent));
+  gtk_window_set_modal (GTK_WINDOW (dialog), modal);
+  gtk_print_unix_dialog_set_manual_capabilities (GTK_PRINT_UNIX_DIALOG (dialog),
+                                                 can_preview () ? GTK_PRINT_CAPABILITY_PREVIEW : 0 |
+                                                 GTK_PRINT_CAPABILITY_PAGE_SET |
+                                                 GTK_PRINT_CAPABILITY_COPIES |
+                                                 GTK_PRINT_CAPABILITY_COLLATE |
+                                                 GTK_PRINT_CAPABILITY_REVERSE |
+                                                 GTK_PRINT_CAPABILITY_SCALE |
+                                                 GTK_PRINT_CAPABILITY_NUMBER_UP);
+  gtk_print_unix_dialog_set_embed_page_setup (GTK_PRINT_UNIX_DIALOG (dialog), TRUE);
+  gtk_print_unix_dialog_set_settings (GTK_PRINT_UNIX_DIALOG (dialog), settings);
+  gtk_print_unix_dialog_set_page_setup (GTK_PRINT_UNIX_DIALOG (dialog), page_setup);
+
+  g_object_unref (settings);
+  g_object_unref (page_setup);
+
+  handle = g_new0 (PrintDialogHandle, 1);
+  handle->impl = object;
+  handle->invocation = invocation;
+  handle->request = g_object_ref (request);
+  handle->dialog = g_object_ref (dialog);
+  handle->external_parent = external_parent;
+
+  g_signal_connect (request, "handle-close", G_CALLBACK (handle_close), handle);
+
+  g_signal_connect (dialog, "response", G_CALLBACK (handle_prepare_print_response), handle);
+
+  gtk_widget_realize (dialog);
+
+  surface = gtk_native_get_surface (GTK_NATIVE (dialog));
+  if (external_parent)
+    external_window_set_parent_of (external_parent, surface);
+
+  request_export (request, g_dbus_method_invocation_get_connection (invocation));
+
+  gtk_window_present (GTK_WINDOW (dialog));
+
+  return TRUE;
+}
+
+gboolean
+print_init (GDBusConnection  *bus,
+            GError          **error)
+{
+  GDBusInterfaceSkeleton *helper;
+
+  helper = G_DBUS_INTERFACE_SKELETON (xdp_impl_print_skeleton_new ());
+
+  g_signal_connect (helper, "handle-print", G_CALLBACK (handle_print), NULL);
+  g_signal_connect (helper, "handle-prepare-print", G_CALLBACK (handle_prepare_print), NULL);
+
+  if (!g_dbus_interface_skeleton_export (helper,
+                                         bus,
+                                         DESKTOP_PORTAL_OBJECT_PATH,
+                                         error))
+    return FALSE;
+
+  g_debug ("providing %s", g_dbus_interface_skeleton_get_info (helper)->name);
+
+  return TRUE;
+}
diff --git a/src/print.h b/src/print.h
new file mode 100644
index 0000000..1a27748
--- /dev/null
+++ b/src/print.h
@@ -0,0 +1,26 @@
+/*
+ * Copyright © 2016 Red Hat, Inc
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ *       Matthias Clasen <mclasen redhat com>
+ */
+
+#pragma once
+
+#include <gio/gio.h>
+
+gboolean print_init (GDBusConnection  *bus,
+                     GError          **error);
diff --git a/src/xdg-desktop-portal-gnome.c b/src/xdg-desktop-portal-gnome.c
index 03a24f1..e896195 100644
--- a/src/xdg-desktop-portal-gnome.c
+++ b/src/xdg-desktop-portal-gnome.c
@@ -46,6 +46,7 @@
 #include "background.h"
 #include "filechooser.h"
 #include "lockdown.h"
+#include "print.h"
 #include "screenshot.h"
 #include "screencast.h"
 #include "remotedesktop.h"
@@ -127,6 +128,12 @@ on_bus_acquired (GDBusConnection *connection,
       g_clear_error (&error);
     }
 
+  if (!print_init (connection, &error))
+    {
+      g_warning ("error: %s\n", error->message);
+      g_clear_error (&error);
+    }
+
   if (!screenshot_init (connection, &error))
     {
       g_warning ("error: %s\n", error->message);