[gnome-builder] editor: maintain line/column after reloading file

[Christian Hergert <chergert src gnome org>]

commit c6162d8a789529650d28b3ac07e819ff76f5330e
Author: Christian Hergert <chergert redhat com>
Date:   Tue May 12 10:41:57 2020 -0700

    editor: maintain line/column after reloading file
    
    We want to try to keep the cursor in as close of position as we can to the
    previous form when reloading the file. This tries to maintain that but
    will fallback to the latest line (assuming line is past the last line)
    and then the column up to the last column (assuming line_offset is past
    the end of the line).
    
    Fixes #1211

 src/libide/editor/ide-editor-page-actions.c | 51 ++++++++++++++++++++++++-----
 1 file changed, 42 insertions(+), 9 deletions(-)
---
diff --git a/src/libide/editor/ide-editor-page-actions.c b/src/libide/editor/ide-editor-page-actions.c
index 9f64bd543..26dad6492 100644
--- a/src/libide/editor/ide-editor-page-actions.c
+++ b/src/libide/editor/ide-editor-page-actions.c
@@ -31,37 +31,61 @@
 #include "ide-editor-print-operation.h"
 #include "ide-editor-settings-dialog.h"
 
+typedef struct
+{
+  IdeEditorPage *self;
+  guint line;
+  guint line_offset;
+} ReloadState;
+
+static void
+reload_state_free (ReloadState *state)
+{
+  g_clear_object (&state->self);
+  g_slice_free (ReloadState, state);
+}
+
+G_DEFINE_AUTOPTR_CLEANUP_FUNC (ReloadState, reload_state_free)
+
 static void
 ide_editor_page_actions_reload_cb (GObject      *object,
                                    GAsyncResult *result,
                                    gpointer      user_data)
 {
   IdeBufferManager *bufmgr = (IdeBufferManager *)object;
-  g_autoptr(IdeEditorPage) self = user_data;
+  g_autoptr(ReloadState) state = user_data;
   g_autoptr(IdeBuffer) buffer = NULL;
   g_autoptr(GError) error = NULL;
+  GtkTextIter iter;
 
   g_assert (IDE_IS_BUFFER_MANAGER (bufmgr));
   g_assert (G_IS_ASYNC_RESULT (result));
-  g_assert (IDE_IS_EDITOR_PAGE (self));
+  g_assert (state != NULL);
+  g_assert (IDE_IS_EDITOR_PAGE (state->self));
 
-  if (self->progress_bar != NULL)
-    dzl_gtk_widget_hide_with_fade (GTK_WIDGET (self->progress_bar));
+  if (state->self->progress_bar != NULL)
+    dzl_gtk_widget_hide_with_fade (GTK_WIDGET (state->self->progress_bar));
 
   if (!(buffer = ide_buffer_manager_load_file_finish (bufmgr, result, &error)))
     {
       g_warning ("%s", error->message);
-      ide_page_report_error (IDE_PAGE (self),
+      ide_page_report_error (IDE_PAGE (state->self),
                              /* translators: %s is the error message */
                              _("Failed to load file: %s"), error->message);
-      ide_page_set_failed (IDE_PAGE (self), TRUE);
+      ide_page_set_failed (IDE_PAGE (state->self), TRUE);
     }
   else
     {
-      ide_editor_page_scroll_to_line (self, 0);
+      ide_editor_page_scroll_to_line (state->self, 0);
     }
 
-  gtk_revealer_set_reveal_child (self->modified_revealer, FALSE);
+  gtk_revealer_set_reveal_child (state->self->modified_revealer, FALSE);
+
+  gtk_text_buffer_get_iter_at_line_offset (GTK_TEXT_BUFFER (buffer),
+                                           &iter,
+                                           state->line,
+                                           state->line_offset);
+  gtk_text_buffer_select_range (GTK_TEXT_BUFFER (buffer), &iter, &iter);
 }
 
 static void
@@ -73,6 +97,8 @@ ide_editor_page_actions_reload (GSimpleAction *action,
   g_autoptr(IdeNotification) notif = NULL;
   g_autoptr(IdeContext) context = NULL;
   IdeBufferManager *bufmgr;
+  ReloadState *state;
+  GtkTextIter iter;
   IdeBuffer *buffer;
   GFile *file;
 
@@ -88,13 +114,20 @@ ide_editor_page_actions_reload (GSimpleAction *action,
 
   notif = ide_notification_new ();
 
+  ide_buffer_get_selection_bounds (buffer, &iter, NULL);
+
+  state = g_slice_new0 (ReloadState);
+  state->self = g_object_ref (self);
+  state->line = gtk_text_iter_get_line (&iter);
+  state->line_offset = gtk_text_iter_get_line_offset (&iter);
+
   ide_buffer_manager_load_file_async (bufmgr,
                                       file,
                                       IDE_BUFFER_OPEN_FLAGS_FORCE_RELOAD,
                                       notif,
                                       NULL,
                                       ide_editor_page_actions_reload_cb,
-                                      g_object_ref (self));
+                                      g_steal_pointer (&state));
 
   g_object_bind_property (notif, "progress",
                           self->progress_bar, "fraction",