Don't show a progress bar when previewing for the Qt print dialog.

We don't do much work to do that - we don't print anything before the
first selected page, and once we're finished generating that page, we
terminate the printing process - so it shouldn't need a progress bar.
(If it needs a progress bar, We Have A Problem, as that slows down the
drawing of the dialog box.)

This should prevent the problem seen in bug 12040.

Bug: 12040
Change-Id: I129191e06fff3e1eb59a9631c7395b9e7f650809
Reviewed-on: https://code.wireshark.org/review/14255
Reviewed-by: Guy Harris <guy@alum.mit.edu>

6 files changed, 30 insertions, 24 deletions

diff --git a/file.c b/file.c
index 39fbd6dc16..a0c21b2ddb 100644
--- a/file.c
+++ b/file.c
@@ -1977,7 +1977,8 @@ process_specified_records(capture_file *cf, packet_range_t *range,
     const char *string1, const char *string2, gboolean terminate_is_stop,
     gboolean (*callback)(capture_file *, frame_data *,
                          struct wtap_pkthdr *, const guint8 *, void *),
-    void *callback_args)
+    void *callback_args,
+    gboolean show_progress_bar)
 {
   guint32          framenum;
   frame_data      *fdata;
@@ -2023,7 +2024,7 @@ process_specified_records(capture_file *cf, packet_range_t *range,
        longer than the standard time to create it (otherwise, for a
        large file, we might take considerably longer than that standard
        time in order to get to the next progress bar step). */
-    if (progbar == NULL)
+    if (show_progress_bar && progbar == NULL)
       progbar = delayed_create_progress_dlg(cf->window, string1, string2,
                                             terminate_is_stop,
                                             &cf->stop_flag,
@@ -2158,7 +2159,7 @@ cf_retap_packets(capture_file *cf)
 
   ret = process_specified_records(cf, &range, "Recalculating statistics on",
                                   "all packets", TRUE, retap_packet,
-                                  &callback_args);
+                                  &callback_args, TRUE);
 
   epan_dissect_cleanup(&callback_args.edt);
 
@@ -2347,7 +2348,8 @@ fail:
 }
 
 cf_print_status_t
-cf_print_packets(capture_file *cf, print_args_t *print_args)
+cf_print_packets(capture_file *cf, print_args_t *print_args,
+                 gboolean show_progress_bar)
 {
   print_callback_args_t callback_args;
   gint          data_width;
@@ -2475,7 +2477,7 @@ cf_print_packets(capture_file *cf, print_args_t *print_args)
      told to print. */
   ret = process_specified_records(cf, &print_args->range, "Printing",
                                   "selected packets", TRUE, print_packet,
-                                  &callback_args);
+                                  &callback_args, show_progress_bar);
   epan_dissect_cleanup(&callback_args.edt);
   g_free(callback_args.header_line_buf);
   g_free(callback_args.line_buf);
@@ -2566,7 +2568,7 @@ cf_write_pdml_packets(capture_file *cf, print_args_t *print_args)
      told to print. */
   ret = process_specified_records(cf, &print_args->range, "Writing PDML",
                                   "selected packets", TRUE,
-                                  write_pdml_packet, &callback_args);
+                                  write_pdml_packet, &callback_args, TRUE);
 
   epan_dissect_cleanup(&callback_args.edt);
 
@@ -2648,7 +2650,7 @@ cf_write_psml_packets(capture_file *cf, print_args_t *print_args)
      told to print. */
   ret = process_specified_records(cf, &print_args->range, "Writing PSML",
                                   "selected packets", TRUE,
-                                  write_psml_packet, &callback_args);
+                                  write_psml_packet, &callback_args, TRUE);
 
   epan_dissect_cleanup(&callback_args.edt);
 
@@ -2728,7 +2730,7 @@ cf_write_csv_packets(capture_file *cf, print_args_t *print_args)
      told to print. */
   ret = process_specified_records(cf, &print_args->range, "Writing CSV",
                                   "selected packets", TRUE,
-                                  write_csv_packet, &callback_args);
+                                  write_csv_packet, &callback_args, TRUE);
 
   epan_dissect_cleanup(&callback_args.edt);
 
@@ -2791,9 +2793,9 @@ cf_write_carrays_packets(capture_file *cf, print_args_t *print_args)
   /* Iterate through the list of packets, printing the packets we were
      told to print. */
   ret = process_specified_records(cf, &print_args->range,
-                  "Writing C Arrays",
-                  "selected packets", TRUE,
-                                  carrays_write_packet, &callback_args);
+                                  "Writing C Arrays",
+                                  "selected packets", TRUE,
+                                  carrays_write_packet, &callback_args, TRUE);
 
   epan_dissect_cleanup(&callback_args.edt);
 
@@ -4525,7 +4527,7 @@ cf_save_records(capture_file *cf, const char *fname, guint save_format,
     callback_args.fname = fname;
     callback_args.file_type = save_format;
     switch (process_specified_records(cf, NULL, "Saving", "packets",
-                                      TRUE, save_record, &callback_args)) {
+                                      TRUE, save_record, &callback_args, TRUE)) {
 
     case PSP_FINISHED:
       /* Completed successfully. */
@@ -4763,7 +4765,7 @@ cf_export_specified_packets(capture_file *cf, const char *fname,
   callback_args.fname = fname;
   callback_args.file_type = save_format;
   switch (process_specified_records(cf, range, "Writing", "specified records",
-                                    TRUE, save_record, &callback_args)) {
+                                    TRUE, save_record, &callback_args, TRUE)) {
 
   case PSP_FINISHED:
     /* Completed successfully. */
diff --git a/file.h b/file.h
index 2403e24707..a52f9a454e 100644
--- a/file.h
+++ b/file.h
@@ -420,9 +420,11 @@ void cf_timestamp_auto_precision(capture_file *cf);
  *
  * @param cf the capture file
  * @param print_args the arguments what and how to print
+ * @param show_progress_bar TRUE if a progress bar is to be shown
  * @return one of cf_print_status_t
  */
-cf_print_status_t cf_print_packets(capture_file *cf, print_args_t *print_args);
+cf_print_status_t cf_print_packets(capture_file *cf, print_args_t *print_args,
+                                   gboolean show_progress_bar);
 
 /**
  * Print (export) the capture file into PDML format.
diff --git a/ui/gtk/print_dlg.c b/ui/gtk/print_dlg.c
index d3f9b5deb7..262e953695 100644
--- a/ui/gtk/print_dlg.c
+++ b/ui/gtk/print_dlg.c
@@ -1109,7 +1109,7 @@ print_ok_cb(GtkWidget *ok_bt, gpointer parent_w)
       g_assert_not_reached();
       return;
     }
-    status = cf_print_packets(&cfile, args);
+    status = cf_print_packets(&cfile, args, TRUE);
   }
   switch (status) {
 
diff --git a/ui/qt/export_dissection_dialog.cpp b/ui/qt/export_dissection_dialog.cpp
index afd84243cc..53f6f869e1 100644
--- a/ui/qt/export_dissection_dialog.cpp
+++ b/ui/qt/export_dissection_dialog.cpp
@@ -168,7 +168,7 @@ int ExportDissectionDialog::exec()
                 open_failure_alert_box(print_args_.file, errno, TRUE);
                 return QDialog::Rejected;
             }
-            status = cf_print_packets(cap_file_, &print_args_);
+            status = cf_print_packets(cap_file_, &print_args_, TRUE);
             break;
         case export_type_csv:       /* CSV */
             status = cf_write_csv_packets(cap_file_, &print_args_);
diff --git a/ui/qt/print_dialog.cpp b/ui/qt/print_dialog.cpp
index 58f4cb0bba..07979b5306 100644
--- a/ui/qt/print_dialog.cpp
+++ b/ui/qt/print_dialog.cpp
@@ -145,6 +145,8 @@ gboolean PrintDialog::printHeader()
 
     if (page_pos_ > page_top) {
         if (in_preview_) {
+            // When generating a preview, only generate the first page;
+            // if we're past the first page, stop the printing process.
             return FALSE;
         }
         // Second and subsequent pages only
@@ -178,6 +180,8 @@ gboolean PrintDialog::printLine(int indent, const char *line)
 
     if (cur_printer_->pageRect().height() < page_pos_ + out_rect.height()) {
         if (in_preview_) {
+            // When generating a preview, only generate the first page;
+            // if we're past the first page, stop the printing process.
             return FALSE;
         }
         if (*line == '\0') { // Separator
@@ -257,12 +261,10 @@ void PrintDialog::printPackets(QPrinter *printer, bool in_preview)
                              QMessageBox::Ok);
         close();
     }
-    // cf_print_packets updates the progress bar which in turn calls
-    // WiresharkApplication::processEvents(), which can make the preview trip
-    // over itself.
-    preview_->setUpdatesEnabled(false);
-    cf_print_packets(cap_file_, &print_args_);
-    preview_->setUpdatesEnabled(true);
+    // Don't show a progress bar if we're previewing; if it takes a
+    // significant amount of time to generate a preview of the first
+    // page, We Have A Real Problem
+    cf_print_packets(cap_file_, &print_args_, in_preview ? FALSE : TRUE);
     cur_printer_ = NULL;
     cur_painter_ = NULL;
     painter.end();
diff --git a/ui/win32/file_dlg_win32.c b/ui/win32/file_dlg_win32.c
index b7630dfd14..15eca21a30 100644
--- a/ui/win32/file_dlg_win32.c
+++ b/ui/win32/file_dlg_win32.c
@@ -697,7 +697,7 @@ win32_export_file(HWND h_wnd, capture_file *cf, export_type_e export_type) {
                     g_free( (void *) ofn);
                     return;
                 }
-                status = cf_print_packets(cf, &print_args);
+                status = cf_print_packets(cf, &print_args, TRUE);
                 break;
             case export_type_ps:        /* PostScript (r) */
                 print_args.stream = print_stream_ps_new(TRUE, print_args.file);
@@ -706,7 +706,7 @@ win32_export_file(HWND h_wnd, capture_file *cf, export_type_e export_type) {
                     g_free( (void *) ofn);
                     return;
                 }
-                status = cf_print_packets(cf, &print_args);
+                status = cf_print_packets(cf, &print_args, TRUE);
                 break;
             case export_type_csv:       /* CSV */
                 status = cf_write_csv_packets(cf, &print_args);