[gnome-builder/wip/gtk4-port] libide/sourceview: handle request to scroll to insert

[Christian Hergert <chergert src gnome org>]

commit e40c45efc0a4a4273bcc1921da3657b14c1a478d
Author: Christian Hergert <chergert redhat com>
Date:   Mon Apr 11 14:01:48 2022 -0700

    libide/sourceview: handle request to scroll to insert
    
    Generally we don't want to use this API, as it forces all views to scroll
    to the insert location which are observing the buffer. However, it is used
    for things like "restore-cursor" at load time, so we should at least start
    with it working even if we remove it later.

 src/libide/sourceview/ide-source-view.c | 47 +++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
---
diff --git a/src/libide/sourceview/ide-source-view.c b/src/libide/sourceview/ide-source-view.c
index 1e2619a02..557e0eaff 100644
--- a/src/libide/sourceview/ide-source-view.c
+++ b/src/libide/sourceview/ide-source-view.c
@@ -25,6 +25,7 @@
 #include <glib/gi18n.h>
 #include <math.h>
 
+#include <libide-code.h>
 #include <libide-gtk.h>
 
 #include "ide-source-view.h"
@@ -238,6 +239,47 @@ ide_source_view_click_pressed_cb (IdeSourceView   *self,
   IDE_EXIT;
 }
 
+static void
+ide_source_view_buffer_request_scroll_to_insert_cb (IdeSourceView *self,
+                                                    IdeBuffer     *buffer)
+{
+  GtkTextMark *mark;
+  GtkTextIter iter;
+
+  IDE_ENTRY;
+
+  g_assert (IDE_IS_SOURCE_VIEW (self));
+  g_assert (IDE_IS_BUFFER (buffer));
+
+  mark = gtk_text_buffer_get_insert (GTK_TEXT_BUFFER (buffer));
+  gtk_text_buffer_get_iter_at_mark (GTK_TEXT_BUFFER (buffer), &iter, mark);
+  gtk_text_view_scroll_to_iter (GTK_TEXT_VIEW (self),
+                                &iter, 0.25, TRUE, 1.0, 0.5);
+
+  IDE_EXIT;
+}
+
+static void
+ide_source_view_notify_buffer_cb (IdeSourceView *self,
+                                  GParamSpec    *pspec,
+                                  gpointer       user_data)
+{
+  GtkTextBuffer *buffer;
+
+  g_assert (IDE_IS_SOURCE_VIEW (self));
+
+  buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (self));
+
+  if (IDE_IS_BUFFER (buffer))
+    {
+      g_signal_connect_object (buffer,
+                               "request-scroll-to-insert",
+                               G_CALLBACK (ide_source_view_buffer_request_scroll_to_insert_cb),
+                               self,
+                               G_CONNECT_SWAPPED);
+    }
+}
+
 static void
 ide_source_view_dispose (GObject *object)
 {
@@ -382,6 +424,11 @@ ide_source_view_init (IdeSourceView *self)
   GtkStyleContext *style_context;
   GtkEventController *click;
 
+  g_signal_connect (self,
+                    "notify::buffer",
+                    G_CALLBACK (ide_source_view_notify_buffer_cb),
+                    NULL);
+
   /* Setup our extra menu so that consumers can use
    * ide_source_view_append_men() or similar to update menus.
    */