[gtksourceview] gutter: use signal group to track adjustments

[Christian Hergert <chergert src gnome org>]

commit 1507256374d56e5849a28adba89d5f55a40ad0f9
Author: Christian Hergert <chergert redhat com>
Date:   Sun Feb 28 14:32:27 2021 -0800

    gutter: use signal group to track adjustments
    
    Rather than expecting to have the adjustments available when the widget
    is created, we should delay setup and track changes as they occur.
    
    Thankfully, we have GtkSourceSignalGroup now which makes that rather
    trivial to be more complete in our support here.
    
    Fixes #175

 gtksourceview/gtksourcegutter.c | 79 +++++++++++++++++++++++++----------------
 1 file changed, 48 insertions(+), 31 deletions(-)
---
diff --git a/gtksourceview/gtksourcegutter.c b/gtksourceview/gtksourcegutter.c
index 889a7b2e..72828939 100644
--- a/gtksourceview/gtksourcegutter.c
+++ b/gtksourceview/gtksourcegutter.c
@@ -24,6 +24,7 @@
 #include "gtksourcegutter-private.h"
 #include "gtksourcegutterlines.h"
 #include "gtksourcegutterlines-private.h"
+#include "gtksourcesignalgroup-private.h"
 #include "gtksourcestylescheme-private.h"
 #include "gtksourceview.h"
 #include "gtksourcegutterrenderer.h"
@@ -74,13 +75,12 @@ struct _GtkSourceGutter
        GtkSourceView        *view;
        GList                *renderers;
        GtkSourceGutterLines *lines;
+       GtkSourceSignalGroup *signals;
+       GBinding             *target_binding;
 
        GtkTextWindowType     window_type;
        GtkOrientation        orientation;
 
-       gulong                adj_changed_handler;
-       gulong                adj_upper_changed_handler;
-
        guint                 is_drawing : 1;
 };
 
@@ -202,38 +202,29 @@ on_adjustment_upper_changed (GtkAdjustment   *adj,
        _gtk_source_gutter_queue_draw (gutter);
 }
 
-static GtkAdjustment *
-get_adjustment (GtkSourceGutter *gutter,
-               GtkSourceView   *view)
+static void
+connect_view (GtkSourceGutter *gutter,
+              GtkSourceView   *view)
 {
+       const gchar *property_name;
+
+       g_assert (GTK_SOURCE_IS_GUTTER (gutter));
+       g_assert (GTK_SOURCE_IS_VIEW (view));
+       g_assert (gutter->target_binding == NULL);
+
        if (gutter->window_type == GTK_TEXT_WINDOW_LEFT ||
            gutter->window_type == GTK_TEXT_WINDOW_RIGHT)
        {
-               return gtk_scrollable_get_vadjustment (GTK_SCROLLABLE (view));
+               property_name = "vadjustment";
        }
        else
        {
-               return gtk_scrollable_get_hadjustment (GTK_SCROLLABLE (view));
+               property_name = "hadjustment";
        }
-}
 
-static void
-connect_view (GtkSourceGutter *gutter,
-              GtkSourceView   *view)
-{
-       g_assert (GTK_SOURCE_IS_GUTTER (gutter));
-       g_assert (GTK_SOURCE_IS_VIEW (view));
-
-       gutter->adj_changed_handler =
-               g_signal_connect (get_adjustment (gutter, view),
-                                 "value-changed",
-                                 G_CALLBACK (on_adjustment_value_changed),
-                                 gutter);
-       gutter->adj_upper_changed_handler =
-               g_signal_connect (get_adjustment (gutter, view),
-                                 "notify::upper",
-                                 G_CALLBACK (on_adjustment_upper_changed),
-                                 gutter);
+       g_object_bind_property (view, property_name,
+                               gutter->signals, "target",
+                               G_BINDING_SYNC_CREATE);
 }
 
 static void
@@ -243,10 +234,7 @@ disconnect_view (GtkSourceGutter *gutter,
        g_assert (GTK_SOURCE_IS_GUTTER (gutter));
        g_assert (GTK_SOURCE_IS_VIEW (view));
 
-       g_clear_signal_handler (&gutter->adj_changed_handler,
-                               get_adjustment (gutter, view));
-       g_clear_signal_handler (&gutter->adj_upper_changed_handler,
-                               get_adjustment (gutter, view));
+       g_clear_pointer (&gutter->target_binding, g_binding_unbind);
 }
 
 static void
@@ -376,6 +364,22 @@ gtk_source_gutter_constructed (GObject *object)
        G_OBJECT_CLASS (gtk_source_gutter_parent_class)->constructed (object);
 }
 
+static void
+gtk_source_gutter_dispose (GObject *object)
+{
+       GtkSourceGutter *gutter = (GtkSourceGutter *)object;
+
+       g_clear_pointer (&gutter->target_binding, g_binding_unbind);
+
+       if (gutter->signals != NULL)
+       {
+               gtk_source_signal_group_set_target (gutter->signals, NULL);
+               g_clear_object (&gutter->signals);
+       }
+
+       G_OBJECT_CLASS (gtk_source_gutter_parent_class)->dispose (object);
+}
+
 static void
 gtk_source_gutter_class_init (GtkSourceGutterClass *klass)
 {
@@ -383,6 +387,7 @@ gtk_source_gutter_class_init (GtkSourceGutterClass *klass)
        GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
 
        object_class->constructed = gtk_source_gutter_constructed;
+       object_class->dispose = gtk_source_gutter_dispose;
        object_class->get_property = gtk_source_gutter_get_property;
        object_class->set_property = gtk_source_gutter_set_property;
 
@@ -427,7 +432,19 @@ gtk_source_gutter_init (GtkSourceGutter *gutter)
        GtkGesture *click;
        GtkEventController *motion;
 
-  gutter->window_type = GTK_TEXT_WINDOW_LEFT;
+       gutter->window_type = GTK_TEXT_WINDOW_LEFT;
+
+       gutter->signals = gtk_source_signal_group_new (GTK_TYPE_ADJUSTMENT);
+       gtk_source_signal_group_connect_object (gutter->signals,
+                                               "value-changed",
+                                               G_CALLBACK (on_adjustment_value_changed),
+                                               gutter,
+                                               0);
+       gtk_source_signal_group_connect_object (gutter->signals,
+                                               "notify::upper",
+                                               G_CALLBACK (on_adjustment_upper_changed),
+                                               gutter,
+                                               0);
 
        /* Setup fallback click handling */
        click = gtk_gesture_click_new ();