[evolution] I#2062 - Limit number of previewed messages on mbox file import

[Milan Crha <mcrha src gnome org>]

commit 0300697b4e5f5fcf2104fbe9f1aea5a4f63626dc
Author: Milan Crha <mcrha redhat com>
Date:   Thu Oct 6 17:25:31 2022 +0200

    I#2062 - Limit number of previewed messages on mbox file import
    
    Closes https://gitlab.gnome.org/GNOME/evolution/-/issues/2062

 src/mail/importers/evolution-mbox-importer.c | 30 ++++++++++++++++++++++------
 1 file changed, 24 insertions(+), 6 deletions(-)
---
diff --git a/src/mail/importers/evolution-mbox-importer.c b/src/mail/importers/evolution-mbox-importer.c
index bc0ff9e4fd..5123de3b46 100644
--- a/src/mail/importers/evolution-mbox-importer.c
+++ b/src/mail/importers/evolution-mbox-importer.c
@@ -424,7 +424,8 @@ mbox_get_preview (EImport *ei,
        GtkListStore *store = NULL;
        GtkTreeIter iter;
        GtkWidget *preview_widget = NULL;
-       gboolean any_read = FALSE;
+       gint n_read = 0;
+       gboolean shortened_list = FALSE;
 
        if (!create_preview_func || !fill_preview_func)
                return NULL;
@@ -453,7 +454,13 @@ mbox_get_preview (EImport *ei,
        while (camel_mime_parser_step (mp, NULL, NULL) == CAMEL_MIME_PARSER_STATE_FROM) {
                CamelMimeMessage *msg;
 
-               any_read = TRUE;
+               n_read++;
+
+               /* Read only first few messages, not the whole mbox */
+               if (n_read > 10) {
+                       shortened_list = TRUE;
+                       break;
+               }
 
                msg = camel_mime_message_new ();
                if (!camel_mime_part_construct_from_parser_sync (
@@ -469,7 +476,7 @@ mbox_get_preview (EImport *ei,
                camel_mime_parser_step (mp, NULL, NULL);
        }
 
-       if (!any_read) {
+       if (!n_read) {
                CamelStream *stream;
 
                stream = camel_stream_fs_new_with_name (filename, O_RDONLY, 0, NULL);
@@ -515,9 +522,20 @@ mbox_get_preview (EImport *ei,
                        tree_view, -1, C_("mboxImp", "From"),
                        gtk_cell_renderer_text_new (), "text", 1, NULL);
 
-               if (gtk_tree_model_iter_n_children (GTK_TREE_MODEL (store), NULL) > 1)
-                       e_web_view_preview_show_tree_view (
-                               E_WEB_VIEW_PREVIEW (preview));
+               if (gtk_tree_model_iter_n_children (GTK_TREE_MODEL (store), NULL) > 1) {
+                       e_web_view_preview_show_tree_view (E_WEB_VIEW_PREVIEW (preview));
+
+                       if (shortened_list) {
+                               GtkTreeIter iter;
+
+                               gtk_list_store_append (store, &iter);
+                               gtk_list_store_set (store, &iter,
+                                       0, _("Showing only first few messages, more will be imported"),
+                                       1, "",
+                                       2, NULL,
+                                       -1);
+                       }
+               }
 
                create_preview_func (G_OBJECT (preview), &preview_widget);
                if (!preview_widget) {