[gtk+/gtk-3-22] printing: Do not truncate job names in GtkPrintOperation

[Carlos Garcia Campos <carlosgc src gnome org>]

commit 255225584e200029c041a308dc7cf0eda555ae97
Author: Carlos Garcia Campos <cgarcia igalia com>
Date:   Tue Nov 8 11:44:44 2016 +0100

    printing: Do not truncate job names in GtkPrintOperation
    
    We are currently truncating job names to 255 bytes, because that's the
    maximum allowed length of job-name attribute in CUPS. This is a CUPS
    limitation that GtkPrintOperation shouldn't need to know, and it
    shouldn't affect other backends, that might have other limitations or
    even no limitation at all. This has another side effect, that what you
    set as GtkPrintOperation:job-name could be different to what you get if
    the property is truncated, this is not documented in
    gtk_print_operation_set_job_name(). So, I think the job name should be
    truncated by the CUPS backend, right before setting the job-name
    attribute.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=774097

 gtk/gtkprintoperation.c                          |   24 +++------------------
 modules/printbackends/cups/gtkprintbackendcups.c |   20 ++++++++++++++++-
 2 files changed, 22 insertions(+), 22 deletions(-)
---
diff --git a/gtk/gtkprintoperation.c b/gtk/gtkprintoperation.c
index db53d05..329a07a 100644
--- a/gtk/gtkprintoperation.c
+++ b/gtk/gtkprintoperation.c
@@ -1606,33 +1606,17 @@ gtk_print_operation_set_job_name (GtkPrintOperation *op,
                                  const gchar       *job_name)
 {
   GtkPrintOperationPrivate *priv;
-  gchar *end;
 
   g_return_if_fail (GTK_IS_PRINT_OPERATION (op));
   g_return_if_fail (job_name != NULL);
 
   priv = op->priv;
 
-  g_free (priv->job_name);
-  /*
-   * according to http://datatracker.ietf.org/doc/rfc2911/,
-   * job names MUST NOT exceed 255 (MAX) octets.
-   *
-   * CUPS will not print jobs with names exceeding 255 chars.
-   */
-  if (strlen (job_name) > 255)
-    {
-      end = g_utf8_find_prev_char (job_name, job_name + 255);
-      priv->job_name = g_utf8_substring (job_name,
-                                         0,
-                                         g_utf8_pointer_to_offset (job_name,
-                                                                   end));
-    }
-  else
-    {
-      priv->job_name = g_strdup (job_name);
-    }
+  if (g_strcmp0 (priv->job_name, job_name) == 0)
+    return;
 
+  g_free (priv->job_name);
+  priv->job_name = g_strdup (job_name);
 
   g_object_notify (G_OBJECT (op), "job-name");
 }
diff --git a/modules/printbackends/cups/gtkprintbackendcups.c 
b/modules/printbackends/cups/gtkprintbackendcups.c
index d114076..2056434 100644
--- a/modules/printbackends/cups/gtkprintbackendcups.c
+++ b/modules/printbackends/cups/gtkprintbackendcups.c
@@ -752,10 +752,26 @@ gtk_print_backend_cups_print_stream (GtkPrintBackend         *print_backend,
                                    NULL, printer_absolute_uri);
 
   title = gtk_print_job_get_title (job);
-  if (title)
+  if (title) {
+    char *title_truncated = NULL;
+    size_t title_bytes = strlen (title);
+
+    if (title_bytes >= IPP_MAX_NAME)
+      {
+        gchar *end;
+
+        end = g_utf8_find_prev_char (title, title + IPP_MAX_NAME - 1);
+        title_truncated = g_utf8_substring (title,
+                                            0,
+                                            g_utf8_pointer_to_offset (title, end));
+      }
+
     gtk_cups_request_ipp_add_string (request, IPP_TAG_OPERATION,
                                      IPP_TAG_NAME, "job-name",
-                                     NULL, title);
+                                     NULL,
+                                     title_truncated ? title_truncated : title);
+    g_free (title_truncated);
+  }
 
   options_data = g_new0 (CupsOptionsData, 1);
   options_data->request = request;