[gedit] PreferencesDialog: improve code to install extra style scheme

[Sébastien Wilmet <swilmet src gnome org>]

commit 5e588d97887b98bcc7ce6073953673f7384f855f
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Wed Jun 3 14:46:11 2020 +0200

    PreferencesDialog: improve code to install extra style scheme
    
    To simplify and modernize that part of the code.
    
    - Use GIO.
    - Show error message in the warning dialog.

 gedit/gedit-preferences-dialog.c | 270 +++++++++++++++++----------------------
 1 file changed, 114 insertions(+), 156 deletions(-)
---
diff --git a/gedit/gedit-preferences-dialog.c b/gedit/gedit-preferences-dialog.c
index 0b9db5046..3e8933c62 100644
--- a/gedit/gedit-preferences-dialog.c
+++ b/gedit/gedit-preferences-dialog.c
@@ -500,180 +500,134 @@ style_scheme_notify_cb (GtkSourceStyleSchemeChooser *chooser,
        update_style_scheme_buttons_sensisitivity (dlg);
 }
 
-/*
- * file_copy:
- * @name: a pointer to a %NULL-terminated string, that names
- * the file to be copied, in the GLib file name encoding
- * @dest_name: a pointer to a %NULL-terminated string, that is the
- * name for the destination file, in the GLib file name encoding
- * @error: return location for a #GError, or %NULL
- *
- * Copies file @name to @dest_name.
- *
- * If the call was successful, it returns %TRUE. If the call was not
- * successful, it returns %FALSE and sets @error. The error domain
- * is #G_FILE_ERROR. Possible error
- * codes are those in the #GFileError enumeration.
- *
- * Return value: %TRUE on success, %FALSE otherwise.
- */
-static gboolean
-file_copy (const gchar  *name,
-          const gchar  *dest_name,
-          GError      **error)
+static GFile *
+get_user_style_scheme_destination_file (GFile *src_file)
 {
-       gchar *contents;
-       gsize length;
-       gchar *dest_dir;
-
-       /* FIXME - Paolo (Aug. 13, 2007):
-        * Since the style scheme files are relatively small, we can implement
-        * file copy getting all the content of the source file in a buffer and
-        * then write the content to the destination file. In this way we
-        * can use the g_file_get_contents and g_file_set_contents and avoid to
-        * write custom code to copy the file (with sane error management).
-        * If needed we can improve this code later. */
-
-       g_return_val_if_fail (name != NULL, FALSE);
-       g_return_val_if_fail (dest_name != NULL, FALSE);
-       g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
-
-       /* Note: we allow to copy a file to itself since this is not a problem
-        * in our use case */
-
-       /* Ensure the destination directory exists */
-       dest_dir = g_path_get_dirname (dest_name);
-
-       errno = 0;
-       if (g_mkdir_with_parents (dest_dir, 0755) != 0)
-       {
-               gint save_errno = errno;
-               gchar *display_filename = g_filename_display_name (dest_dir);
-
-               g_set_error (error,
-                            G_FILE_ERROR,
-                            g_file_error_from_errno (save_errno),
-                            _("Directory “%s” could not be created: g_mkdir_with_parents() failed: %s"),
-                            display_filename,
-                            g_strerror (save_errno));
+       gchar *basename;
+       const gchar *styles_dir;
+       GFile *dest_file;
 
-               g_free (dest_dir);
-               g_free (display_filename);
+       basename = g_file_get_basename (src_file);
+       g_return_val_if_fail (basename != NULL, NULL);
 
-               return FALSE;
-       }
+       styles_dir = gedit_dirs_get_user_styles_dir ();
+       dest_file = g_file_new_build_filename (styles_dir, basename, NULL);
 
-       g_free (dest_dir);
+       g_free (basename);
+       return dest_file;
+}
 
-       if (!g_file_get_contents (name, &contents, &length, error))
+/* Returns: whether @src_file has been correctly copied to @dest_file. */
+static gboolean
+copy_file (GFile   *src_file,
+          GFile   *dest_file,
+          GError **error)
+{
+       if (g_file_equal (src_file, dest_file))
+       {
                return FALSE;
+       }
 
-       if (!g_file_set_contents (dest_name, contents, length, error))
+       if (!tepl_utils_create_parent_directories (dest_file, NULL, error))
        {
-               g_free (contents);
                return FALSE;
        }
 
-       g_free (contents);
-
-       return TRUE;
+       return g_file_copy (src_file,
+                           dest_file,
+                           G_FILE_COPY_OVERWRITE | G_FILE_COPY_TARGET_DEFAULT_PERMS,
+                           NULL, /* cancellable */
+                           NULL, NULL, /* progress callback */
+                           error);
 }
 
-/*
- * install_style_scheme:
- * @fname: the file name of the style scheme to be installed
- *
- * Install a new user scheme.
- * This function copies @fname in #GEDIT_STYLES_DIR and ask the style manager to
- * recompute the list of available style schemes. It then checks if a style
- * scheme with the right file name exists.
- *
- * If the call was succesful, it returns the id of the installed scheme
- * otherwise %NULL.
- *
- * Return value: the id of the installed scheme, %NULL otherwise.
+/* Get the style scheme ID of @user_style_scheme_file if it has been correctly
+ * installed and @user_style_scheme_file is a valid style scheme file.
  */
-static GtkSourceStyleScheme *
-install_style_scheme (const gchar *fname)
+static const gchar *
+get_style_scheme_id_after_installing_user_style_scheme (GFile *user_style_scheme_file)
 {
        GtkSourceStyleSchemeManager *manager;
-       gchar *new_file_name = NULL;
-       gchar *dirname;
-       const gchar *styles_dir;
-       GError *error = NULL;
-       gboolean copied = FALSE;
-       const gchar * const *ids;
-
-       g_return_val_if_fail (fname != NULL, NULL);
+       const gchar * const *scheme_ids;
+       gint i;
 
        manager = gtk_source_style_scheme_manager_get_default ();
+       gtk_source_style_scheme_manager_force_rescan (manager);
 
-       dirname = g_path_get_dirname (fname);
-       styles_dir = gedit_dirs_get_user_styles_dir ();
+       scheme_ids = gtk_source_style_scheme_manager_get_scheme_ids (manager);
 
-       if (strcmp (dirname, styles_dir) != 0)
+       for (i = 0; scheme_ids != NULL && scheme_ids[i] != NULL; i++)
        {
-               gchar *basename;
-
-               basename = g_path_get_basename (fname);
-               new_file_name = g_build_filename (styles_dir, basename, NULL);
-               g_free (basename);
+               const gchar *cur_scheme_id = scheme_ids[i];
+               GtkSourceStyleScheme *scheme;
+               const gchar *filename;
+               GFile *scheme_file;
 
-               /* Copy the style scheme file into GEDIT_STYLES_DIR */
-               if (!file_copy (fname, new_file_name, &error))
+               scheme = gtk_source_style_scheme_manager_get_scheme (manager, cur_scheme_id);
+               filename = gtk_source_style_scheme_get_filename (scheme);
+               if (filename == NULL)
                {
-                       g_free (new_file_name);
-                       g_free (dirname);
-
-                       g_message ("Cannot install style scheme:\n%s",
-                                  error->message);
-
-                       g_error_free (error);
+                       continue;
+               }
 
-                       return NULL;
+               scheme_file = g_file_new_for_path (filename);
+               if (g_file_equal (scheme_file, user_style_scheme_file))
+               {
+                       g_object_unref (scheme_file);
+                       return cur_scheme_id;
                }
 
-               copied = TRUE;
-       }
-       else
-       {
-               new_file_name = g_strdup (fname);
+               g_object_unref (scheme_file);
        }
 
-       g_free (dirname);
+       return NULL;
+}
 
-       /* Reload the available style schemes */
-       gtk_source_style_scheme_manager_force_rescan (manager);
+/* Returns: (nullable): the installed style scheme ID, or %NULL on failure. */
+static const gchar *
+install_style_scheme (GFile   *src_file,
+                     GError **error)
+{
+       GFile *dest_file;
+       gboolean copied;
+       const gchar *installed_style_scheme_id = NULL;
+       GError *my_error = NULL;
 
-       /* Check the new style scheme has been actually installed */
-       ids = gtk_source_style_scheme_manager_get_scheme_ids (manager);
+       g_return_val_if_fail (G_IS_FILE (src_file), NULL);
+       g_return_val_if_fail (error == NULL || *error == NULL, NULL);
 
-       while (*ids != NULL)
+       dest_file = get_user_style_scheme_destination_file (src_file);
+       g_return_val_if_fail (dest_file != NULL, NULL);
+
+       copied = copy_file (src_file, dest_file, &my_error);
+       if (my_error != NULL)
        {
-               GtkSourceStyleScheme *scheme;
-               const gchar *filename;
+               g_propagate_error (error, my_error);
+               g_object_unref (dest_file);
+               return NULL;
+       }
 
-               scheme = gtk_source_style_scheme_manager_get_scheme (manager, *ids);
+       installed_style_scheme_id = get_style_scheme_id_after_installing_user_style_scheme (dest_file);
 
-               filename = gtk_source_style_scheme_get_filename (scheme);
-
-               if (filename && (strcmp (filename, new_file_name) == 0))
+       if (installed_style_scheme_id == NULL && copied)
+       {
+               /* The style scheme has not been correctly installed. */
+               g_file_delete (dest_file, NULL, &my_error);
+               if (my_error != NULL)
                {
-                       /* The style scheme has been correctly installed */
-                       g_free (new_file_name);
+                       gchar *dest_file_parse_name = g_file_get_parse_name (dest_file);
+
+                       g_warning ("Failed to delete the file “%s”: %s",
+                                  dest_file_parse_name,
+                                  my_error->message);
 
-                       return scheme;
+                       g_free (dest_file_parse_name);
+                       g_clear_error (&my_error);
                }
-               ++ids;
        }
 
-       /* The style scheme has not been correctly installed */
-       if (copied)
-               g_unlink (new_file_name);
-
-       g_free (new_file_name);
-
-       return NULL;
+       g_object_unref (dest_file);
+       return installed_style_scheme_id;
 }
 
 /*
@@ -709,49 +663,53 @@ uninstall_style_scheme (GtkSourceStyleScheme *scheme)
 
 static void
 add_scheme_chooser_response_cb (GeditFileChooserDialog *chooser,
-                               gint                    res_id,
-                               GeditPreferencesDialog *dlg)
+                               gint                    response_id,
+                               GeditPreferencesDialog *dialog)
 {
        GFile *file;
-       gchar *filename;
-       GtkSourceStyleScheme *scheme;
+       const gchar *scheme_id;
+       GeditSettings *settings;
+       GSettings *editor_settings;
+       GError *error = NULL;
 
-       if (res_id != GTK_RESPONSE_ACCEPT)
+       if (response_id != GTK_RESPONSE_ACCEPT)
        {
                gedit_file_chooser_dialog_hide (chooser);
                return;
        }
 
        file = gedit_file_chooser_dialog_get_file (chooser);
-
        if (file == NULL)
        {
                return;
        }
 
-       filename = g_file_get_path (file);
-       g_object_unref (file);
-
-       if (filename == NULL)
-       {
-               return;
-       }
-
        gedit_file_chooser_dialog_hide (chooser);
 
-       scheme = install_style_scheme (filename);
-       g_free (filename);
+       scheme_id = install_style_scheme (file, &error);
+       g_object_unref (file);
 
-       if (scheme == NULL)
+       if (scheme_id == NULL)
        {
-               tepl_utils_show_warning_dialog (GTK_WINDOW (dlg),
-                                               _("The selected color scheme cannot be installed."));
+               if (error != NULL)
+               {
+                       tepl_utils_show_warning_dialog (GTK_WINDOW (dialog),
+                                                       _("The selected color scheme cannot be installed: 
%s"),
+                                                       error->message);
+               }
+               else
+               {
+                       tepl_utils_show_warning_dialog (GTK_WINDOW (dialog),
+                                                       _("The selected color scheme cannot be installed."));
+               }
 
+               g_clear_error (&error);
                return;
        }
 
-       g_settings_set_string (dlg->editor, GEDIT_SETTINGS_SCHEME,
-                              gtk_source_style_scheme_get_id (scheme));
+       settings = _gedit_settings_get_singleton ();
+       editor_settings = _gedit_settings_peek_editor_settings (settings);
+       g_settings_set_string (editor_settings, GEDIT_SETTINGS_SCHEME, scheme_id);
 }
 
 static void