printing: Create temporary queues for Avahi printers

This change extends set of Avahi advertised printers which
works with Gtk's CUPS print backend.

It creates a temporary queue (local printer) for each
Avahi printer in CUPS instead of accessing them directly
(via CUPS library).

This makes some printers work which did not work before and
also gives users more options to change in the print dialog.

This also changes naming of printers to be in accordance with CUPS.
It uses '_' instead of '-' and has hostname appended for CUPS remote
printers.

2 files changed, 243 insertions, 57 deletions

diff --git a/modules/printbackends/cups/gtkprintbackendcups.c b/modules/printbackends/cups/gtkprintbackendcups.c
index d95d632e0b..b1ee0584d0 100644
--- a/modules/printbackends/cups/gtkprintbackendcups.c
+++ b/modules/printbackends/cups/gtkprintbackendcups.c
@@ -154,6 +154,9 @@ struct _GtkPrintBackendCups
   gboolean      secrets_service_available;
   guint         secrets_service_watch_id;
   GCancellable *secrets_service_cancellable;
+
+  GList *temporary_queues_in_construction;
+  GList *temporary_queues_removed;
 };
 
 static GObjectClass *backend_parent_class;
@@ -238,6 +241,11 @@ static void                 secrets_service_vanished_cb             (GDBusConnec
                                                                      const gchar *name,
                                                                      gpointer user_data);
 
+static void                 create_temporary_queue                  (GtkPrintBackendCups *backend,
+                                                                     const gchar         *printer_name,
+                                                                     const gchar         *printer_uri,
+                                                                     const gchar         *device_uri);
+
 static void
 gtk_print_backend_cups_register_type (GTypeModule *module)
 {
@@ -897,6 +905,9 @@ gtk_print_backend_cups_init (GtkPrintBackendCups *backend_cups)
     gtk_cups_secrets_service_watch (secrets_service_appeared_cb,
                                     secrets_service_vanished_cb,
                                     backend_cups);
+
+  backend_cups->temporary_queues_in_construction = NULL;
+  backend_cups->temporary_queues_removed = NULL;
 }
 
 static void
@@ -933,6 +944,12 @@ gtk_print_backend_cups_finalize (GObject *object)
       g_bus_unwatch_name (backend_cups->secrets_service_watch_id);
     }
 
+  g_list_free_full (backend_cups->temporary_queues_in_construction, g_free);
+  backend_cups->temporary_queues_in_construction = NULL;
+
+  g_list_free_full (backend_cups->temporary_queues_removed, g_free);
+  backend_cups->temporary_queues_removed = NULL;
+
   backend_parent_class->finalize (object);
 }
 
@@ -1861,8 +1878,28 @@ static void
 mark_printer_inactive (GtkPrinter      *printer,
                        GtkPrintBackend *backend)
 {
-  gtk_printer_set_is_active (printer, FALSE);
-  g_signal_emit_by_name (backend, "printer-removed", printer);
+  GtkPrinterCups *cups_printer = GTK_PRINTER_CUPS (printer);
+  GList          *iter;
+
+  if (cups_printer->is_temporary)
+    {
+      /* Do not recreate printers which disappeared from Avahi. */
+      iter = g_list_find_custom (GTK_PRINT_BACKEND_CUPS (backend)->temporary_queues_removed,
+                                 gtk_printer_get_name (printer), (GCompareFunc) g_strcmp0);
+      if (iter == NULL)
+        {
+          /* Recreate temporary queue since they are created for 60 seconds only. */
+          create_temporary_queue (GTK_PRINT_BACKEND_CUPS (backend),
+                                  gtk_printer_get_name (printer),
+                                  cups_printer->printer_uri,
+                                  cups_printer->temporary_queue_device_uri);
+        }
+    }
+  else
+    {
+      gtk_printer_set_is_active (printer, FALSE);
+      g_signal_emit_by_name (backend, "printer-removed", printer);
+    }
 }
 
 static gint
@@ -1913,7 +1950,8 @@ static const char * const printer_attrs[] =
     "multiple-document-handling-supported",
     "copies-supported",
     "number-up-supported",
-    "device-uri"
+    "device-uri",
+    "printer-is-temporary"
   };
 
 /* Attributes we're interested in for printers without PPD */
@@ -2010,6 +2048,7 @@ typedef struct
   gchar    *output_bin_default;
   GList    *output_bin_supported;
   gchar    *original_device_uri;
+  gboolean  is_temporary;
 } PrinterSetupInfo;
 
 static void
@@ -2395,6 +2434,13 @@ cups_printer_handle_attribute (GtkPrintBackendCups *cups_backend,
     {
       info->original_device_uri = g_strdup (ippGetString (attr, 0, NULL));
     }
+  else if (strcmp (ippGetName (attr), "printer-is-temporary") == 0)
+    {
+      if (ippGetBoolean (attr, 0) == 1)
+        info->is_temporary = TRUE;
+      else
+        info->is_temporary = FALSE;
+    }
   else
     {
       GTK_NOTE (PRINTING,
@@ -2430,12 +2476,7 @@ cups_create_printer (GtkPrintBackendCups *cups_backend,
   cups_printer = gtk_printer_cups_new (info->printer_name, backend, NULL);
 #endif
 
-  if (info->avahi_printer)
-    {
-      cups_printer->device_uri = g_strdup_printf ("/%s",
-                                                  info->avahi_resource_path);
-    }
-  else
+  if (!info->avahi_printer)
     {
       cups_printer->device_uri = g_strdup_printf ("/printers/%s",
                                                   info->printer_name);
@@ -2799,6 +2840,8 @@ cups_request_printer_info_cb (GtkPrintBackendCups *cups_backend,
           GTK_PRINTER_CUPS (printer)->output_bin_default = info->output_bin_default;
           GTK_PRINTER_CUPS (printer)->output_bin_supported = info->output_bin_supported;
 
+          GTK_PRINTER_CUPS (printer)->is_temporary = info->is_temporary;
+
           gtk_printer_set_has_details (printer, TRUE);
           g_signal_emit_by_name (printer, "details-acquired", TRUE);
 
@@ -2866,8 +2909,10 @@ cups_request_printer_info (GtkPrinterCups *printer)
 typedef struct
 {
   gchar               *printer_uri;
+  gchar               *device_uri;
   gchar               *location;
-  gchar               *host;
+  gchar               *address;
+  gchar               *hostname;
   gint                 port;
   gchar               *printer_name;
   gchar               *name;
@@ -2924,6 +2969,88 @@ find_printer_by_uuid (GtkPrintBackendCups *backend,
   return result;
 }
 
+static void
+cups_create_local_printer_cb (GtkPrintBackendCups *print_backend,
+                              GtkCupsResult       *result,
+                              gpointer             user_data)
+{
+  ipp_attribute_t *attr;
+  gchar           *printer_name = NULL;
+  ipp_t           *response;
+  GList           *iter;
+
+  response = gtk_cups_result_get_response (result);
+
+  if (ippGetStatusCode (response) <= IPP_OK_CONFLICT)
+    {
+      if ((attr = ippFindAttribute (response, "printer-uri-supported", IPP_TAG_URI)) != NULL)
+        {
+          printer_name = g_strdup (g_strrstr (ippGetString (attr, 0, NULL), "/") + 1);
+        }
+
+      GTK_NOTE (PRINTING,
+                g_print ("CUPS Backend: Created local printer %s\n", printer_name));
+    }
+  else
+    {
+      GTK_NOTE (PRINTING,
+                g_print ("CUPS Backend: Creating of local printer failed: %d\n", ippGetStatusCode (response)));
+    }
+
+  iter = g_list_find_custom (print_backend->temporary_queues_in_construction, printer_name, (GCompareFunc) g_strcmp0);
+  if (iter != NULL)
+    {
+      g_free (iter->data);
+      print_backend->temporary_queues_in_construction = g_list_delete_link (print_backend->temporary_queues_in_construction, iter);
+    }
+
+  g_free (printer_name);
+}
+
+/*
+ *  Create CUPS temporary queue.
+ */
+static void
+create_temporary_queue (GtkPrintBackendCups *backend,
+                        const gchar         *printer_name,
+                        const gchar         *printer_uri,
+                        const gchar         *device_uri)
+{
+  GtkCupsRequest *request;
+  GList          *iter;
+
+  /* There can be several queues with the same name (ipp and ipps versions of the same printer) */
+  iter = g_list_find_custom (backend->temporary_queues_in_construction, printer_name, (GCompareFunc) g_strcmp0);
+  if (iter != NULL)
+    return;
+
+  GTK_NOTE (PRINTING,
+            g_print ("CUPS Backend: Creating local printer %s\n", printer_name));
+
+  backend->temporary_queues_in_construction = g_list_prepend (backend->temporary_queues_in_construction, g_strdup (printer_name));
+
+  request = gtk_cups_request_new_with_username (NULL,
+                                                GTK_CUPS_POST,
+                                                IPP_OP_CUPS_CREATE_LOCAL_PRINTER,
+                                                NULL,
+                                                NULL,
+                                                NULL,
+                                                NULL);
+
+  gtk_cups_request_ipp_add_string (request, IPP_TAG_OPERATION, IPP_TAG_URI,
+                                   "printer-uri", NULL, printer_uri);
+  gtk_cups_request_ipp_add_string (request, IPP_TAG_PRINTER, IPP_TAG_NAME,
+                                   "printer-name", NULL, printer_name);
+  gtk_cups_request_ipp_add_string (request, IPP_TAG_PRINTER, IPP_TAG_URI,
+                                   "device-uri", NULL, device_uri);
+
+  cups_request_execute (backend,
+                        request,
+                        (GtkPrintCupsResponseCallbackFunc) cups_create_local_printer_cb,
+                        NULL,
+                        NULL);
+}
+
 /*
  *  Create new GtkPrinter from informations included in TXT records.
  */
@@ -2933,6 +3060,15 @@ create_cups_printer_from_avahi_data (AvahiConnectionTestData *data)
   PrinterSetupInfo *info = g_slice_new0 (PrinterSetupInfo);
   GtkPrinter       *printer;
 
+  printer = gtk_print_backend_find_printer (GTK_PRINT_BACKEND (data->backend), data->printer_name);
+  if (printer != NULL)
+    {
+      /* A printer with this name is already present in this backend. It is probably the same printer
+       * on another protocol (IPv4 vs IPv6).
+       */
+      return;
+    }
+
   info->avahi_printer = TRUE;
   info->printer_name = data->printer_name;
   info->printer_uri = data->printer_uri;
@@ -2997,8 +3133,9 @@ create_cups_printer_from_avahi_data (AvahiConnectionTestData *data)
       GTK_PRINTER_CUPS (printer)->avahi_type = g_strdup (data->type);
       GTK_PRINTER_CUPS (printer)->avahi_domain = g_strdup (data->domain);
       GTK_PRINTER_CUPS (printer)->printer_uri = g_strdup (data->printer_uri);
+      GTK_PRINTER_CUPS (printer)->temporary_queue_device_uri = g_strdup (data->device_uri);
       g_free (GTK_PRINTER_CUPS (printer)->hostname);
-      GTK_PRINTER_CUPS (printer)->hostname = g_strdup (data->host);
+      GTK_PRINTER_CUPS (printer)->hostname = g_strdup (data->hostname);
       GTK_PRINTER_CUPS (printer)->port = data->port;
       gtk_printer_set_location (printer, data->location);
       gtk_printer_set_state_message (printer, info->state_msg);
@@ -3031,10 +3168,11 @@ avahi_connection_test_cb (GObject      *source_object,
 {
   AvahiConnectionTestData *data = (AvahiConnectionTestData *) user_data;
   GSocketConnection       *connection;
+  GError                  *error = NULL;
 
   connection = g_socket_client_connect_to_host_finish (G_SOCKET_CLIENT (source_object),
                                                        res,
-                                                       NULL);
+                                                       &error);
   g_object_unref (source_object);
 
   if (connection != NULL)
@@ -3044,15 +3182,25 @@ avahi_connection_test_cb (GObject      *source_object,
 
       create_cups_printer_from_avahi_data (data);
     }
+  else
+    {
+      GTK_NOTE (PRINTING,
+                g_warning ("CUPS Backend: Can not connect to %s: %s\n",
+                           data->address,
+                           error->message));
+      g_error_free (error);
+    }
 
   g_free (data->printer_uri);
   g_free (data->location);
-  g_free (data->host);
+  g_free (data->address);
+  g_free (data->hostname);
   g_free (data->printer_name);
   g_free (data->name);
   g_free (data->resource_path);
   g_free (data->type);
   g_free (data->domain);
+  g_free (data->device_uri);
   g_free (data);
 }
 
@@ -3091,17 +3239,17 @@ avahi_service_resolver_cb (GObject      *source_object,
   AvahiConnectionTestData *data;
   GtkPrintBackendCups     *backend;
   const gchar             *name;
-  const gchar             *host;
+  const gchar             *hostname;
   const gchar             *type;
   const gchar             *domain;
   const gchar             *address;
-  const gchar             *protocol_string;
   GVariant                *output;
   GVariant                *txt;
   GVariant                *child;
   guint32                  flags;
   guint16                  port;
   GError                  *error = NULL;
+  GList                   *iter;
   gchar                   *tmp;
   gchar                   *printer_name;
   gchar                  **printer_name_strv;
@@ -3128,7 +3276,7 @@ avahi_service_resolver_cb (GObject      *source_object,
                      &name,
                      &type,
                      &domain,
-                     &host,
+                     &hostname,
                      &aprotocol,
                      &address,
                      &port,
@@ -3193,51 +3341,50 @@ avahi_service_resolver_cb (GObject      *source_object,
 
       if (data->resource_path != NULL)
         {
-          if (data->got_printer_type &&
-              (g_str_has_prefix (data->resource_path, "printers/") ||
-               g_str_has_prefix (data->resource_path, "classes/")))
+          /*
+           * Create name of temporary queue from the name of the discovered service.
+           * This emulates the way how CUPS creates the name.
+           */
+          printer_name = g_strdup_printf ("%s", name);
+          g_strcanon (printer_name, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789", '_');
+
+          printer_name_strv = g_strsplit_set (printer_name, "_", -1);
+          printer_name_compressed_strv = g_new0 (gchar *, g_strv_length (printer_name_strv) + 1);
+          for (i = 0, j = 0; printer_name_strv[i] != NULL; i++)
             {
-              /* This is a CUPS printer advertised via Avahi */
-              printer_name = g_strrstr (data->resource_path, "/");
-              if (printer_name != NULL && printer_name[0] != '\0')
-                data->printer_name = g_strdup (printer_name + 1);
-              else
-                data->printer_name = g_strdup (data->resource_path);
-            }
-          else
-            {
-              printer_name = g_strdup (name);
-              g_strcanon (printer_name, PRINTER_NAME_ALLOWED_CHARACTERS, '-');
-
-              printer_name_strv = g_strsplit_set (printer_name, "-", -1);
-              printer_name_compressed_strv = g_new0 (gchar *, g_strv_length (printer_name_strv) + 1);
-              for (i = 0, j = 0; printer_name_strv[i] != NULL; i++)
+              if (printer_name_strv[i][0] != '\0')
                 {
-                  if (printer_name_strv[i][0] != '\0')
-                    {
-                      printer_name_compressed_strv[j] = printer_name_strv[i];
-                      j++;
-                    }
+                  printer_name_compressed_strv[j] = printer_name_strv[i];
+                  j++;
                 }
+            }
+
+          data->printer_name = g_strjoinv ("_", printer_name_compressed_strv);
 
-              data->printer_name = g_strjoinv ("-", printer_name_compressed_strv);
+          g_strfreev (printer_name_strv);
+          g_free (printer_name_compressed_strv);
+          g_free (printer_name);
 
-              g_strfreev (printer_name_strv);
-              g_free (printer_name_compressed_strv);
-              g_free (printer_name);
+          iter = g_list_find_custom (backend->temporary_queues_removed, data->printer_name, (GCompareFunc) g_strcmp0);
+          if (iter != NULL)
+            {
+              g_free (iter->data);
+              backend->temporary_queues_removed = g_list_delete_link (backend->temporary_queues_removed, iter);
             }
 
           if (g_strcmp0 (type, "_ipp._tcp") == 0)
-            protocol_string = "ipp";
-          else
-            protocol_string = "ipps";
-
-          if (aprotocol == AVAHI_PROTO_INET6)
-            data->printer_uri = g_strdup_printf ("%s://[%s]:%u/%s", protocol_string, address, port, data->resource_path);
+            {
+              data->printer_uri = g_strdup_printf ("ipp://localhost/printers/%s", data->printer_name);
+              data->device_uri = g_strdup_printf ("ipp://%s:%d/%s", hostname, port, data->resource_path);
+            }
           else
-            data->printer_uri = g_strdup_printf ("%s://%s:%u/%s", protocol_string, address, port, data->resource_path);
+            {
+              data->printer_uri = g_strdup_printf ("ipps://localhost/printers/%s", data->printer_name);
+              data->device_uri = g_strdup_printf ("ipps://%s:%d/%s", hostname, port, data->resource_path);
+            }
 
-          data->host = g_strdup (address);
+          data->address = g_strdup (address);
+          data->hostname = g_strdup (hostname);
           data->port = port;
 
           data->name = g_strdup (name);
@@ -3351,6 +3498,9 @@ avahi_service_browser_signal_handler (GDBusConnection *connection,
                                  backend->avahi_default_printer) == 0)
                     g_clear_pointer (&backend->avahi_default_printer, g_free);
 
+                  backend->temporary_queues_removed = g_list_prepend (backend->temporary_queues_removed,
+                    g_strdup (gtk_printer_get_name (GTK_PRINTER (printer))));
+
                   g_signal_emit_by_name (backend, "printer-removed", printer);
                   gtk_print_backend_remove_printer (GTK_PRINT_BACKEND (backend),
                                                     GTK_PRINTER (printer));
@@ -3463,7 +3613,6 @@ avahi_create_browsers (GObject      *source_object,
                                          avahi_service_browser_signal_handler,
                                          cups_backend,
                                          NULL);
-
   /*
    * Create service browsers for _ipp._tcp and _ipps._tcp services.
    */
@@ -3591,6 +3740,12 @@ cups_request_printer_list_cb (GtkPrintBackendCups *cups_backend,
             continue;
         }
 
+      /* Do not show printer for queue which was removed from Avahi. */
+      iter = g_list_find_custom (GTK_PRINT_BACKEND_CUPS (backend)->temporary_queues_removed,
+                                 info->printer_name, (GCompareFunc) g_strcmp0);
+      if (iter != NULL)
+        continue;
+
       if (info->got_printer_type)
         {
           if (info->default_printer && !cups_backend->got_default_printer)
@@ -3626,7 +3781,24 @@ cups_request_printer_list_cb (GtkPrintBackendCups *cups_backend,
 	  printer = cups_create_printer (cups_backend, info);
 	  list_has_changed = TRUE;
 	}
-
+      else if (GTK_PRINTER_CUPS (printer)->avahi_browsed && info->is_temporary)
+        {
+          /*
+           * A temporary queue was created for a printer found via Avahi.
+           * We modify the placeholder GtkPrinter to point to the temporary queue
+           * instead of removing the placeholder GtkPrinter and creating new GtkPrinter.
+           */
+
+          g_object_ref (printer);
+
+          GTK_PRINTER_CUPS (printer)->avahi_browsed = FALSE;
+          GTK_PRINTER_CUPS (printer)->is_temporary = TRUE;
+          g_free (GTK_PRINTER_CUPS (printer)->device_uri);
+          GTK_PRINTER_CUPS (printer)->device_uri = g_strdup_printf ("/printers/%s",
+                                                                    info->printer_name);
+          gtk_printer_set_has_details (printer, FALSE);
+          cups_printer_request_details (printer);
+        }
       else
 	g_object_ref (printer);
 
@@ -3657,6 +3829,7 @@ cups_request_printer_list_cb (GtkPrintBackendCups *cups_backend,
       GTK_PRINTER_CUPS (printer)->supports_number_up = info->supports_number_up;
       GTK_PRINTER_CUPS (printer)->number_of_covers = info->number_of_covers;
       GTK_PRINTER_CUPS (printer)->covers = g_strdupv (info->covers);
+      GTK_PRINTER_CUPS (printer)->is_temporary = info->is_temporary;
       status_changed = gtk_printer_set_job_count (printer, info->job_count);
       status_changed |= gtk_printer_set_location (printer, info->location);
       status_changed |= gtk_printer_set_description (printer,
@@ -3979,7 +4152,10 @@ cups_request_ppd (GtkPrinter *printer)
     }
   else
     {
-      hostname = cups_printer->hostname;
+      if (cups_printer->is_temporary)
+        hostname = cupsServer ();
+      else
+        hostname = cups_printer->hostname;
       port = cups_printer->port;
       resource = g_strdup_printf ("/printers/%s.ppd",
                                   gtk_printer_cups_get_ppd_name (GTK_PRINTER_CUPS (printer)));
@@ -4352,8 +4528,16 @@ cups_printer_request_details (GtkPrinter *printer)
   GtkPrinterCups *cups_printer;
 
   cups_printer = GTK_PRINTER_CUPS (printer);
-  if (!cups_printer->reading_ppd &&
-      gtk_printer_cups_get_ppd (cups_printer) == NULL)
+
+  if (cups_printer->avahi_browsed)
+    {
+      create_temporary_queue (GTK_PRINT_BACKEND_CUPS (gtk_printer_get_backend (printer)),
+                              gtk_printer_get_name (printer),
+                              cups_printer->printer_uri,
+                              cups_printer->temporary_queue_device_uri);
+    }
+  else if (!cups_printer->reading_ppd &&
+           gtk_printer_cups_get_ppd (cups_printer) == NULL)
     {
       if (cups_printer->remote && !cups_printer->avahi_browsed)
         {
diff --git a/modules/printbackends/cups/gtkprintercups.h b/modules/printbackends/cups/gtkprintercups.h
index bdc30ca4f3..c8ad83fcb9 100644
--- a/modules/printbackends/cups/gtkprintercups.h
+++ b/modules/printbackends/cups/gtkprintercups.h
@@ -56,7 +56,9 @@ struct _GtkPrinterCups
   gchar *original_hostname;
   gchar *original_resource;
   gint original_port;
-  gboolean request_original_uri; /* Request PPD from original hostname */
+  gboolean request_original_uri;     /* Request PPD from original hostname */
+  gboolean is_temporary;             /* This printer is temporary queue */
+  gchar *temporary_queue_device_uri; /* Device uri of temporary queue for this printer */
 
   ipp_pstate_t state;
   gboolean reading_ppd;