[evolution] e-mail-reader: Add safety checks on return value from e_mail_reader_get_selected_uids()

[Milan Crha <mcrha src gnome org>]

commit d36cb281ed9369c8570cd2e0e41537bd30b22875
Author: Milan Crha <mcrha redhat com>
Date:   Tue May 4 18:26:45 2021 +0200

    e-mail-reader: Add safety checks on return value from e_mail_reader_get_selected_uids()
    
    Discovered by static analyzers.

 src/mail/e-mail-reader.c | 33 +++++++++++++++++++++++----------
 1 file changed, 23 insertions(+), 10 deletions(-)
---
diff --git a/src/mail/e-mail-reader.c b/src/mail/e-mail-reader.c
index 684c5bbb57..ac49eb20d8 100644
--- a/src/mail/e-mail-reader.c
+++ b/src/mail/e-mail-reader.c
@@ -898,7 +898,6 @@ action_mail_label_new_cb (GtkAction *action,
        EMailLabelListStore *label_store;
        EMailBackend *backend;
        EMailSession *session;
-       CamelFolder *folder;
        GtkTreeModel *model;
        GtkTreeIter iter;
        GtkWidget *dialog;
@@ -938,15 +937,20 @@ action_mail_label_new_cb (GtkAction *action,
        g_warn_if_fail (gtk_tree_model_iter_nth_child (model, &iter, NULL, n_children - 1));
        label_tag = e_mail_label_list_store_get_tag (label_store, &iter);
 
-       folder = e_mail_reader_ref_folder (reader);
        uids = e_mail_reader_get_selected_uids (reader);
+       if (uids) {
+               CamelFolder *folder;
 
-       for (ii = 0; ii < uids->len; ii++)
-               camel_folder_set_message_user_flag (
-                       folder, uids->pdata[ii], label_tag, TRUE);
+               folder = e_mail_reader_ref_folder (reader);
 
-       g_clear_object (&folder);
-       g_ptr_array_unref (uids);
+               for (ii = 0; ii < uids->len; ii++) {
+                       camel_folder_set_message_user_flag (
+                               folder, uids->pdata[ii], label_tag, TRUE);
+               }
+
+               g_clear_object (&folder);
+               g_ptr_array_unref (uids);
+       }
 
        g_free (label_tag);
 
@@ -967,13 +971,16 @@ action_mail_label_none_cb (GtkAction *action,
        gboolean valid;
        guint ii;
 
+       uids = e_mail_reader_get_selected_uids (reader);
+       if (!uids)
+               return;
+
        backend = e_mail_reader_get_backend (reader);
        session = e_mail_backend_get_session (backend);
        label_store = e_mail_ui_session_get_label_store (
                E_MAIL_UI_SESSION (session));
 
        folder = e_mail_reader_ref_folder (reader);
-       uids = e_mail_reader_get_selected_uids (reader);
 
        valid = gtk_tree_model_get_iter_first (
                GTK_TREE_MODEL (label_store), &iter);
@@ -2237,8 +2244,11 @@ action_mail_toggle_important_cb (GtkAction *action,
        GPtrArray *uids;
        guint ii;
 
-       folder = e_mail_reader_ref_folder (reader);
        uids = e_mail_reader_get_selected_uids_with_collapsed_threads (reader);
+       if (!uids)
+               return;
+
+       folder = e_mail_reader_ref_folder (reader);
 
        camel_folder_freeze (folder);
 
@@ -4161,8 +4171,11 @@ action_mail_label_cb (GtkToggleAction *action,
        tag = g_object_get_data (G_OBJECT (action), "tag");
        g_return_if_fail (tag != NULL);
 
-       folder = e_mail_reader_ref_folder (reader);
        uids = e_mail_reader_get_selected_uids (reader);
+       if (!uids)
+               return;
+
+       folder = e_mail_reader_ref_folder (reader);
 
        camel_folder_freeze (folder);
        for (ii = 0; ii < uids->len; ii++) {