[gtksourceview] snippets: avoid creating informative until necessary

[Christian Hergert <chergert src gnome org>]

commit 0fa24e457bfba4b686550088354ea63bb5ccef07
Author: Christian Hergert <chergert redhat com>
Date:   Fri May 13 17:57:33 2022 -0700

    snippets: avoid creating informative until necessary
    
    This fixes GtkSourceStyleSchemePreview so that it doesn't create a new
    informative for every widget. GtkSourceMap as well.

 gtksourceview/gtksourceview-snippets.c | 36 ++++++++++++++++++++++------------
 1 file changed, 24 insertions(+), 12 deletions(-)
---
diff --git a/gtksourceview/gtksourceview-snippets.c b/gtksourceview/gtksourceview-snippets.c
index 64d41ec9..b0662093 100644
--- a/gtksourceview/gtksourceview-snippets.c
+++ b/gtksourceview/gtksourceview-snippets.c
@@ -312,6 +312,17 @@ gtk_source_view_snippets_update_informative (GtkSourceViewSnippets *snippets)
                goto hide_informative;
        }
 
+       if (snippets->informative == NULL)
+       {
+               snippets->informative = g_object_new (GTK_SOURCE_TYPE_INFORMATIVE,
+                                                     "position", GTK_POS_TOP,
+                                                     "message-type", GTK_MESSAGE_INFO,
+                                                      "icon-name", "completion-snippet-symbolic",
+                                                     NULL);
+               _gtk_source_view_add_assistant (snippets->view,
+                                               GTK_SOURCE_ASSISTANT (snippets->informative));
+       }
+
        _gtk_source_assistant_set_mark (GTK_SOURCE_ASSISTANT (snippets->informative), chunk->begin_mark);
        gtk_source_informative_set_message (snippets->informative, tooltip_text);
 
@@ -327,7 +338,10 @@ gtk_source_view_snippets_update_informative (GtkSourceViewSnippets *snippets)
        return;
 
 hide_informative:
-       gtk_widget_hide (GTK_WIDGET (snippets->informative));
+       if (snippets->informative != NULL)
+       {
+               gtk_widget_hide (GTK_WIDGET (snippets->informative));
+       }
 }
 
 static void
@@ -386,14 +400,6 @@ _gtk_source_view_snippets_init (GtkSourceViewSnippets *snippets,
                _gtk_source_view_snippets_set_buffer (snippets,
                                                      GTK_SOURCE_BUFFER (buffer));
        }
-
-       snippets->informative = g_object_new (GTK_SOURCE_TYPE_INFORMATIVE,
-                                             "position", GTK_POS_TOP,
-                                             "message-type", GTK_MESSAGE_INFO,
-                                             "icon-name", "completion-snippet-symbolic",
-                                             NULL);
-       _gtk_source_view_add_assistant (snippets->view,
-                                       GTK_SOURCE_ASSISTANT (snippets->informative));
 }
 
 void
@@ -415,8 +421,11 @@ _gtk_source_view_snippets_shutdown (GtkSourceViewSnippets *snippets)
        g_clear_signal_handler (&snippets->buffer_cursor_moved_handler,
                                snippets->buffer);
 
-       _gtk_source_view_remove_assistant (snippets->view,
-                                          GTK_SOURCE_ASSISTANT (snippets->informative));
+       if (snippets->informative != NULL)
+       {
+               _gtk_source_view_remove_assistant (snippets->view,
+                                                  GTK_SOURCE_ASSISTANT (snippets->informative));
+       }
 
        if (snippets->snippet_signals != NULL)
        {
@@ -661,7 +670,10 @@ _gtk_source_view_snippets_pop (GtkSourceViewSnippets *snippets)
 
                g_object_unref (snippet);
 
-               gtk_widget_hide (GTK_WIDGET (snippets->informative));
+               if (snippets->informative != NULL)
+               {
+                       gtk_widget_hide (GTK_WIDGET (snippets->informative));
+               }
        }
 
        snippet = g_queue_peek_head (&snippets->queue);