[gtksourceview/wip/completion-fix: 2/2] CompletionContext: more robust code

[Sébastien Wilmet <swilmet src gnome org>]

commit 5d159aa68a2dffdd7a0863706c2b892aad723f94
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Fri Sep 26 21:51:41 2014 +0200

    CompletionContext: more robust code
    
    Buffer changes are now handled correctly.
    gtk_source_completion_context_get_iter() returns a gboolean to tell if
    the iter was set.
    
    Connecting to the mark-set signal is not needed, because the mark can be
    set only in set_iter().

 gtksourceview/gtksourcecompletioncontext.c |  122 +++++++++++++--------------
 gtksourceview/gtksourcecompletioncontext.h |    2 +-
 2 files changed, 60 insertions(+), 64 deletions(-)
---
diff --git a/gtksourceview/gtksourcecompletioncontext.c b/gtksourceview/gtksourcecompletioncontext.c
index 202bd9b..723bdf4 100644
--- a/gtksourceview/gtksourcecompletioncontext.c
+++ b/gtksourceview/gtksourcecompletioncontext.c
@@ -95,23 +95,6 @@ guint context_signals[NUM_SIGNALS] = {0,};
 
 G_DEFINE_TYPE_WITH_PRIVATE (GtkSourceCompletionContext, gtk_source_completion_context, 
G_TYPE_INITIALLY_UNOWNED)
 
-/* FIXME: we use this util to get the buffer from the completion
- * but this object is not robust to a change of the buffer associated
- * to the view. Context lifetime should be short enough to not really
- * matter.
- * (swilmet) This can happen when the GtkSourceView is being destroyed:
- * GtkTextView set the buffer to NULL, then the code here calls
- * gtk_text_view_get_buffer() which creates another buffer... So it would be
- * better to handle buffer changes.
- */
-
-static GtkTextBuffer *
-get_buffer (GtkSourceCompletionContext *context)
-{
-       GtkSourceView *view = gtk_source_completion_get_view (context->priv->completion);
-       return gtk_text_view_get_buffer (GTK_TEXT_VIEW (view));
-}
-
 static void
 gtk_source_completion_context_dispose (GObject *object)
 {
@@ -136,10 +119,25 @@ gtk_source_completion_context_dispose (GObject *object)
 }
 
 static void
-gtk_source_completion_context_set_iter (GtkSourceCompletionContext *context,
-                                        GtkTextIter                *iter)
+set_iter (GtkSourceCompletionContext *context,
+         GtkTextIter                *iter)
 {
-       GtkTextBuffer *buffer = get_buffer (context);
+       GtkTextBuffer *buffer;
+
+       buffer = gtk_text_iter_get_buffer (iter);
+
+       if (context->priv->mark != NULL)
+       {
+               GtkTextBuffer *old_buffer;
+
+               old_buffer = gtk_text_mark_get_buffer (context->priv->mark);
+
+               if (old_buffer != buffer)
+               {
+                       g_object_unref (context->priv->mark);
+                       context->priv->mark = NULL;
+               }
+       }
 
        if (context->priv->mark == NULL)
        {
@@ -150,6 +148,8 @@ gtk_source_completion_context_set_iter (GtkSourceCompletionContext *context,
        {
                gtk_text_buffer_move_mark (buffer, context->priv->mark, iter);
        }
+
+       g_object_notify (G_OBJECT (context), "iter");
 }
 
 static void
@@ -165,12 +165,15 @@ gtk_source_completion_context_set_property (GObject      *object,
                case PROP_COMPLETION:
                        context->priv->completion = g_value_dup_object (value);
                        break;
+
                case PROP_ITER:
-                       gtk_source_completion_context_set_iter (context, (GtkTextIter *) g_value_get_boxed 
(value));
+                       set_iter (context, g_value_get_boxed (value));
                        break;
+
                case PROP_ACTIVATION:
                        context->priv->activation = g_value_get_flags (value);
                        break;
+
                default:
                        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
        }
@@ -189,6 +192,7 @@ gtk_source_completion_context_get_property (GObject    *object,
                case PROP_COMPLETION:
                        g_value_set_object (value, context->priv->completion);
                        break;
+
                case PROP_ITER:
                        {
                                GtkTextIter iter;
@@ -196,51 +200,21 @@ gtk_source_completion_context_get_property (GObject    *object,
                                g_value_set_boxed (value, &iter);
                        }
                        break;
+
                case PROP_ACTIVATION:
                        g_value_set_flags (value, context->priv->activation);
                        break;
+
                default:
                        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
        }
 }
 
 static void
-buffer_mark_set_cb (GtkTextBuffer              *buffer,
-                    GtkTextIter                *iter,
-                    GtkTextMark                *mark,
-                    GtkSourceCompletionContext *context)
-{
-       if (mark == context->priv->mark)
-       {
-               g_object_notify (G_OBJECT (context), "iter");
-       }
-}
-
-static void
-gtk_source_completion_context_constructed (GObject *object)
-{
-       GtkSourceCompletionContext *context;
-       GtkTextBuffer *buffer;
-
-       /* we need to connect after the completion property is set */
-       context = GTK_SOURCE_COMPLETION_CONTEXT (object);
-       buffer = get_buffer (context);
-
-       g_signal_connect_object (buffer,
-                                "mark-set",
-                                G_CALLBACK (buffer_mark_set_cb),
-                                context,
-                                0);
-
-       G_OBJECT_CLASS (gtk_source_completion_context_parent_class)->constructed (object);
-}
-
-static void
 gtk_source_completion_context_class_init (GtkSourceCompletionContextClass *klass)
 {
        GObjectClass *object_class = G_OBJECT_CLASS (klass);
 
-       object_class->constructed = gtk_source_completion_context_constructed;
        object_class->set_property = gtk_source_completion_context_set_property;
        object_class->get_property = gtk_source_completion_context_get_property;
        object_class->dispose = gtk_source_completion_context_dispose;
@@ -345,27 +319,49 @@ gtk_source_completion_context_add_proposals (GtkSourceCompletionContext  *contex
  *
  * Get the iter at which the completion was invoked. Providers can use this
  * to determine how and if to match proposals.
+ *
+ * Returns: %TRUE if @iter is correctly set, %FALSE otherwise.
  **/
-void
+gboolean
 gtk_source_completion_context_get_iter (GtkSourceCompletionContext *context,
                                         GtkTextIter                *iter)
 {
-       GtkTextBuffer *buffer;
-
-       g_return_if_fail (GTK_SOURCE_IS_COMPLETION_CONTEXT (context));
+       GtkTextBuffer *mark_buffer;
+       GtkSourceView *view;
+       GtkTextBuffer *completion_buffer;
 
-       buffer = get_buffer (context);
+       g_return_val_if_fail (GTK_SOURCE_IS_COMPLETION_CONTEXT (context), FALSE);
 
-       if (context->priv->mark != NULL)
-       {
-               gtk_text_buffer_get_iter_at_mark (buffer, iter, context->priv->mark);
-       }
-       else
+       if (context->priv->mark == NULL)
        {
                /* This should never happen: context should be always be created
                   providing a position iter */
                g_warning ("Completion context without mark");
+               return FALSE;
+       }
+
+       mark_buffer = gtk_text_mark_get_buffer (context->priv->mark);
+
+       if (mark_buffer == NULL)
+       {
+               return FALSE;
+       }
+
+       view = gtk_source_completion_get_view (context->priv->completion);
+       if (view == NULL)
+       {
+               return FALSE;
        }
+
+       completion_buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (view));
+
+       if (completion_buffer != mark_buffer)
+       {
+               return FALSE;
+       }
+
+       gtk_text_buffer_get_iter_at_mark (mark_buffer, iter, context->priv->mark);
+       return TRUE;
 }
 
 /**
diff --git a/gtksourceview/gtksourcecompletioncontext.h b/gtksourceview/gtksourcecompletioncontext.h
index e0e0ce0..ad919c6 100644
--- a/gtksourceview/gtksourcecompletioncontext.h
+++ b/gtksourceview/gtksourcecompletioncontext.h
@@ -78,7 +78,7 @@ void           gtk_source_completion_context_add_proposals    (GtkSourceCompletionContext
                                                                 GList                        *proposals,
                                                                 gboolean                      finished);
 
-void            gtk_source_completion_context_get_iter         (GtkSourceCompletionContext   *context,
+gboolean        gtk_source_completion_context_get_iter         (GtkSourceCompletionContext   *context,
                                                                 GtkTextIter                  *iter);
 
 GtkSourceCompletionActivation