Drop the Big GDK Lock

GDK has a lock to mark critical sections inside the backends.
Additionally, code that would re-enter into the GTK main loop was
supposed to hold the lock.

Back in the Good Old Days™ this was guaranteed to kind of work only on
the X11 backend, and would cause a neat explosion on any other GDK
backend.

During GTK+ 3.x we deprecated the API to enter and leave the critical
sections, and now we can remove all the internal uses of the lock, since
external API that uses GTK+ 4.x won't be able to hold the GDK lock.

https://bugzilla.gnome.org/show_bug.cgi?id=793124

3 files changed, 11 insertions, 52 deletions

diff --git a/modules/input/gtkimcontextmultipress.c b/modules/input/gtkimcontextmultipress.c
index f62e42b1b8..d3c52b08c3 100644
--- a/modules/input/gtkimcontextmultipress.c
+++ b/modules/input/gtkimcontextmultipress.c
@@ -201,8 +201,6 @@ on_timeout (gpointer data)
 {
   GtkImContextMultipress *multipress_context;
 
-  gdk_threads_enter ();
-
   multipress_context = GTK_IM_CONTEXT_MULTIPRESS (data);
 
   /* A certain amount of time has passed, so we will assume that the user
@@ -211,8 +209,6 @@ on_timeout (gpointer data)
 
   multipress_context->timeout_id = 0;
 
-  gdk_threads_leave ();
-
   return G_SOURCE_REMOVE; /* don't call me again */
 }
 
diff --git a/modules/printbackends/cups/gtkprintbackendcups.c b/modules/printbackends/cups/gtkprintbackendcups.c
index 4e6091ea2d..40e7a61375 100644
--- a/modules/printbackends/cups/gtkprintbackendcups.c
+++ b/modules/printbackends/cups/gtkprintbackendcups.c
@@ -553,8 +553,6 @@ cups_print_cb (GtkPrintBackendCups *print_backend,
   GError *error = NULL;
   CupsPrintStreamData *ps = user_data;
 
-  gdk_threads_enter ();
-
   GTK_NOTE (PRINTING,
             g_print ("CUPS Backend: %s\n", G_STRFUNC));
 
@@ -589,8 +587,6 @@ cups_print_cb (GtkPrintBackendCups *print_backend,
 
   if (error)
     g_error_free (error);
-
-  gdk_threads_leave ();
 }
 
 typedef struct {
@@ -1709,12 +1705,10 @@ cups_request_job_info_cb (GtkPrintBackendCups *print_backend,
   int state;
   gboolean done;
 
-  gdk_threads_enter ();
-
   if (data->job == NULL)
     {
       cups_job_poll_data_free (data);
-      goto done;
+      return;
     }
 
   data->counter++;
@@ -1781,9 +1775,6 @@ cups_request_job_info_cb (GtkPrintBackendCups *print_backend,
     }
   else
     cups_job_poll_data_free (data);
-
-done:
-  gdk_threads_leave ();
 }
 
 static void
@@ -2682,8 +2673,6 @@ cups_request_printer_info_cb (GtkPrintBackendCups *cups_backend,
   gboolean          status_changed = FALSE;
   ipp_t            *response;
 
-  gdk_threads_enter ();
-
   GTK_NOTE (PRINTING,
             g_print ("CUPS Backend: %s\n", G_STRFUNC));
 
@@ -2783,8 +2772,6 @@ done:
     }
 
   printer_setup_info_free (info);
-
-  gdk_threads_leave ();
 }
 
 static void
@@ -3454,8 +3441,6 @@ cups_request_printer_list_cb (GtkPrintBackendCups *cups_backend,
   gchar *remote_default_printer = NULL;
   GList *iter;
 
-  gdk_threads_enter ();
-
   list_has_changed = FALSE;
 
   GTK_NOTE (PRINTING,
@@ -3669,8 +3654,6 @@ done:
       set_default_printer (cups_backend, cups_backend->avahi_default_printer);
     }
 #endif
-
-  gdk_threads_leave ();
 }
 
 static void
@@ -3790,8 +3773,6 @@ cups_request_ppd_cb (GtkPrintBackendCups *print_backend,
   GtkPrinter *printer;
   struct stat data_info;
 
-  gdk_threads_enter ();
-
   GTK_NOTE (PRINTING,
             g_print ("CUPS Backend: %s\n", G_STRFUNC));
 
@@ -3815,7 +3796,7 @@ cups_request_ppd_cb (GtkPrintBackendCups *print_backend,
 
       g_signal_emit_by_name (printer, "details-acquired", success);
 
-      goto done;
+      return;
     }
 #endif
 
@@ -3846,15 +3827,12 @@ cups_request_ppd_cb (GtkPrintBackendCups *print_backend,
                                  GTK_PRINTER_CUPS (printer)->port,
                                  GTK_PRINT_BACKEND_CUPS (gtk_printer_get_backend (printer)));
 
-      goto done;
+      return;
     }
 #endif
 
   gtk_printer_set_has_details (printer, TRUE);
   g_signal_emit_by_name (printer, "details-acquired", TRUE);
-
-done:
-  gdk_threads_leave ();
 }
 
 static gboolean
@@ -4204,8 +4182,6 @@ cups_request_default_printer_cb (GtkPrintBackendCups *print_backend,
   ipp_attribute_t *attr;
   GtkPrinter *printer;
 
-  gdk_threads_enter ();
-
   if (gtk_cups_result_is_error (result))
     {
       if (gtk_cups_result_get_error_type (result) == GTK_CUPS_ERROR_AUTH &&
@@ -4242,8 +4218,6 @@ cups_request_default_printer_cb (GtkPrintBackendCups *print_backend,
    */
   if (print_backend->list_printers_poll != 0)
     cups_request_printer_list (print_backend);
-
-  gdk_threads_leave ();
 }
 
 static gboolean
diff --git a/modules/printbackends/file/gtkprintbackendfile.c b/modules/printbackends/file/gtkprintbackendfile.c
index c584b19f9d..775af6647c 100644
--- a/modules/printbackends/file/gtkprintbackendfile.c
+++ b/modules/printbackends/file/gtkprintbackendfile.c
@@ -378,11 +378,10 @@ typedef struct {
   GDestroyNotify dnotify;
 } _PrintStreamData;
 
-/* expects GDK lock to be held */
 static void
-file_print_cb_locked (GtkPrintBackendFile *print_backend,
-                      GError              *error,
-                      gpointer            user_data)
+file_print_cb (GtkPrintBackendFile *print_backend,
+               GError              *error,
+               gpointer            user_data)
 {
   gchar *uri;
 
@@ -399,7 +398,9 @@ file_print_cb_locked (GtkPrintBackendFile *print_backend,
     ps->dnotify (ps->user_data);
 
   gtk_print_job_set_status (ps->job,
-			    (error != NULL)?GTK_PRINT_STATUS_FINISHED_ABORTED:GTK_PRINT_STATUS_FINISHED);
+			    (error != NULL)
+                              ? GTK_PRINT_STATUS_FINISHED_ABORTED
+                              : GTK_PRINT_STATUS_FINISHED);
 
   recent_manager = gtk_recent_manager_get_default ();
   uri = output_file_from_settings (gtk_print_job_get_settings (ps->job), NULL);
@@ -412,18 +413,6 @@ file_print_cb_locked (GtkPrintBackendFile *print_backend,
   g_free (ps);
 }
 
-static void
-file_print_cb (GtkPrintBackendFile *print_backend,
-               GError              *error,
-               gpointer            user_data)
-{
-  gdk_threads_enter ();
-
-  file_print_cb_locked (print_backend, error, user_data);
-
-  gdk_threads_leave ();
-}
-
 static gboolean
 file_write (GIOChannel   *source,
             GIOCondition  con,
@@ -515,8 +504,8 @@ gtk_print_backend_file_print_stream (GtkPrintBackend        *print_backend,
 error:
   if (internal_error != NULL)
     {
-      file_print_cb_locked (GTK_PRINT_BACKEND_FILE (print_backend),
-                            internal_error, ps);
+      file_print_cb (GTK_PRINT_BACKEND_FILE (print_backend),
+                     internal_error, ps);
 
       g_error_free (internal_error);
       return;