[gnome-builder] editor-frame: Add squiggly underlines for invalid regex

[Matthew Leeds <mwleeds src gnome org>]

commit e8d39eeabb9f940f2e5aa2003b8021470bfc6255
Author: Matthew Leeds <mleeds redhat com>
Date:   Thu Jul 14 09:41:10 2016 -0400

    editor-frame: Add squiggly underlines for invalid regex
    
    When an invalid regex is entered in the search entry field, it's
    difficult for the user to tell if there's an issue with their input or
    if the search genuinely returned no results. This commit addresses that
    ambiguity by adding a wavy underline when an invalid regular expression
    is entered in the search field, or an invalid replacement string is
    entered in the replace field (which can contain backreferences). The
    color white is used so that it can still be seen when the background
    is red (which happens when a search returns no results).
    
    https://bugzilla.gnome.org/show_bug.cgi?id=768812

 libide/editor/ide-editor-frame.c |   90 ++++++++++++++++++++++++++++++++++++++
 1 files changed, 90 insertions(+), 0 deletions(-)
---
diff --git a/libide/editor/ide-editor-frame.c b/libide/editor/ide-editor-frame.c
index 6d8438c..d83774e 100644
--- a/libide/editor/ide-editor-frame.c
+++ b/libide/editor/ide-editor-frame.c
@@ -348,6 +348,36 @@ on_cursor_moved (IdeBuffer         *buffer,
     }
 }
 
+static void
+on_regex_error_changed (IdeEditorFrame         *self,
+                        GParamSpec             *pspec,
+                        GtkSourceSearchContext *search_context)
+{
+  g_autoptr(GError) error = NULL;
+  PangoAttrList *attrs;
+
+  g_assert (IDE_IS_EDITOR_FRAME (self));
+  g_assert (GTK_SOURCE_IS_SEARCH_CONTEXT (search_context));
+
+  /*
+   * If the regular expression is invalid, add a white squiggly underline;
+   * otherwise remove it.
+   */
+  attrs = pango_attr_list_new ();
+  error = gtk_source_search_context_get_regex_error (search_context);
+
+  if (error != NULL)
+    {
+      pango_attr_list_insert (attrs, pango_attr_underline_new (PANGO_UNDERLINE_ERROR));
+      pango_attr_list_insert (attrs, pango_attr_underline_color_new (65535, 65535, 65535));
+    }
+
+  gtk_entry_set_attributes (GTK_ENTRY (self->search_entry), attrs);
+  pango_attr_list_unref (attrs);
+
+  update_replace_actions_sensitivity (self);
+}
+
 /**
  * ide_editor_frame_get_source_view:
  *
@@ -485,6 +515,53 @@ on_search_text_changed (IdeEditorFrame          *self,
 }
 
 static void
+check_replace_text (IdeEditorFrame *self)
+{
+  GtkSourceSearchContext *search_context;
+  GtkSourceSearchSettings *search_settings;
+  g_autoptr(GError) error = NULL;
+  PangoAttrList *attrs;
+
+  g_assert (IDE_IS_EDITOR_FRAME (self));
+
+  search_context = ide_source_view_get_search_context (self->source_view);
+  search_settings = gtk_source_search_context_get_settings (search_context);
+
+  attrs = pango_attr_list_new ();
+
+  /*
+   * If the replace expression is invalid, add a white squiggly underline;
+   * otherwise remove it.
+   */
+  if (gtk_source_search_settings_get_regex_enabled (search_settings))
+    {
+      const gchar *replace_text;
+
+      replace_text = gtk_entry_get_text (GTK_ENTRY (self->replace_entry));
+
+      if (!g_regex_check_replacement (replace_text, NULL, &error))
+        {
+          pango_attr_list_insert (attrs, pango_attr_underline_new (PANGO_UNDERLINE_ERROR));
+          pango_attr_list_insert (attrs, pango_attr_underline_color_new (65535, 65535, 65535));
+        }
+    }
+
+  gtk_entry_set_attributes (GTK_ENTRY (self->replace_entry), attrs);
+  pango_attr_list_unref (attrs);
+}
+
+static void
+on_regex_enabled_changed (IdeEditorFrame          *self,
+                          GParamSpec              *pspec,
+                          GtkSourceSearchSettings *search_settings)
+{
+  g_assert (IDE_IS_EDITOR_FRAME (self));
+  g_assert (GTK_SOURCE_IS_SEARCH_SETTINGS (search_settings));
+
+  check_replace_text (self);
+}
+
+static void
 on_replace_text_changed (IdeEditorFrame *self,
                          GParamSpec     *pspec,
                          GtkSearchEntry *replace_entry)
@@ -492,6 +569,7 @@ on_replace_text_changed (IdeEditorFrame *self,
   g_assert (IDE_IS_EDITOR_FRAME (self));
   g_assert (GTK_IS_SEARCH_ENTRY (replace_entry));
 
+  check_replace_text (self);
   update_replace_actions_sensitivity (self);
 }
 
@@ -559,6 +637,12 @@ ide_editor_frame_set_document (IdeEditorFrame *self,
                            self,
                            G_CONNECT_SWAPPED);
 
+  g_signal_connect_object (search_context,
+                           "notify::regex-error",
+                           G_CALLBACK (on_regex_error_changed),
+                           self,
+                           G_CONNECT_SWAPPED);
+
   /*
    * Add search option property actions
    */
@@ -571,6 +655,12 @@ ide_editor_frame_set_document (IdeEditorFrame *self,
                            self,
                            G_CONNECT_SWAPPED);
 
+  g_signal_connect_object (search_settings,
+                           "notify::regex-enabled",
+                           G_CALLBACK (on_regex_enabled_changed),
+                           self,
+                           G_CONNECT_SWAPPED);
+
   g_signal_connect_object (self->replace_entry,
                            "notify::text",
                            G_CALLBACK (on_replace_text_changed),