[gtk/wip/carlosg/imwayland-serials] imwayland: Use serial to prevent redundant outbound changes

[Carlos Garnacho <carlosg src gnome org>]

commit 02fb433a48e7db5a64d3364e57db7be4aae9f75c
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Oct 10 23:39:40 2018 +0200

    imwayland: Use serial to prevent redundant outbound changes
    
    The serial was being used to silence away changes introduced by previous
    commit calls. However the text_input protocol reads:
    
      "When the client receives a done event with a serial different than the
       number of past commit requests, it must proceed as normal, except it
       should not change the current state of the zwp_text_input_v3 object."
    
    It makes more sense to prevent the changes on the zwp_text_input object
    itself, as those would be made redundant by more recent events. But the
    effects of the .done calls should still take place.
    
    Closes: https://gitlab.gnome.org/GNOME/gtk/issues/1365

 modules/input/imwayland.c | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)
---
diff --git a/modules/input/imwayland.c b/modules/input/imwayland.c
index 05e8c0c3d7..f4eb527070 100644
--- a/modules/input/imwayland.c
+++ b/modules/input/imwayland.c
@@ -43,6 +43,7 @@ struct _GtkIMContextWaylandGlobal
   GtkIMContext *current;
 
   guint serial;
+  guint server_serial;
 };
 
 struct _GtkIMContextWaylandClass
@@ -207,11 +208,11 @@ text_input_commit (void                     *data,
 }
 
 static void
-text_input_commit_apply (GtkIMContextWaylandGlobal *global, gboolean valid)
+text_input_commit_apply (GtkIMContextWaylandGlobal *global)
 {
   GtkIMContextWayland *context;
   context = GTK_IM_CONTEXT_WAYLAND (global->current);
-  if (context->pending_commit && valid)
+  if (context->pending_commit)
     g_signal_emit_by_name (global->current, "commit", context->pending_commit);
   g_free (context->pending_commit);
   context->pending_commit = NULL;
@@ -236,8 +237,7 @@ text_input_delete_surrounding_text (void                     *data,
 }
 
 static void
-text_input_delete_surrounding_text_apply (GtkIMContextWaylandGlobal *global,
-  gboolean valid)
+text_input_delete_surrounding_text_apply (GtkIMContextWaylandGlobal *global)
 {
   GtkIMContextWayland *context;
   gboolean retval;
@@ -248,7 +248,7 @@ text_input_delete_surrounding_text_apply (GtkIMContextWaylandGlobal *global,
 
   len = context->pending_surrounding_delete.after_length
       + context->pending_surrounding_delete.before_length;
-  if (len > 0 && valid)
+  if (len > 0)
     g_signal_emit_by_name (global->current, "delete-surrounding",
                            -context->pending_surrounding_delete.before_length,
                            len, &retval);
@@ -262,16 +262,16 @@ text_input_done (void                     *data,
 {
   GtkIMContextWaylandGlobal *global = data;
   gboolean result;
-  gboolean valid;
-  
+
+  global->server_serial = serial;
+
   if (!global->current)
     return;
 
-  valid = serial == global->serial;
-  text_input_delete_surrounding_text_apply(global, valid);
-  text_input_commit_apply(global, valid);
+  text_input_delete_surrounding_text_apply (global);
+  text_input_commit_apply (global);
   g_signal_emit_by_name (global->current, "retrieve-surrounding", &result);
-  text_input_preedit_apply(global);
+  text_input_preedit_apply (global);
 }
 
 static const struct zwp_text_input_v3_listener text_input_listener = {
@@ -348,6 +348,8 @@ notify_surrounding_text (GtkIMContextWayland *context)
     return;
   if (!context->surrounding.text)
     return;
+  if (global->server_serial != global->serial)
+    return;
 
   zwp_text_input_v3_set_surrounding_text (global->text_input,
                                           context->surrounding.text,
@@ -368,6 +370,8 @@ notify_cursor_location (GtkIMContextWayland *context)
     return;
   if (!context->window)
     return;
+  if (global->server_serial != global->serial)
+    return;
 
   rect = context->cursor_rect;
   gdk_window_get_root_coords (context->window, rect.x, rect.y,
@@ -445,6 +449,8 @@ notify_content_type (GtkIMContextWayland *context)
 
   if (global->current != GTK_IM_CONTEXT (context))
     return;
+  if (global->server_serial != global->serial)
+    return;
 
   g_object_get (context,
                 "input-hints", &hints,