[evolution-data-server] I#179 - Calendar: Handle errors in file backend's refresh thread gracefully

[Milan Crha <mcrha src gnome org>]

commit a2b806168d1011c25f6f664d8e8a49fc6aebb601
Author: Milan Crha <mcrha redhat com>
Date:   Tue Jan 21 09:48:10 2020 +0100

    I#179 - Calendar: Handle errors in file backend's refresh thread gracefully
    
    Closes https://gitlab.gnome.org/GNOME/evolution-data-server/issues/179

 src/calendar/backends/file/e-cal-backend-file.c | 29 ++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 6 deletions(-)
---
diff --git a/src/calendar/backends/file/e-cal-backend-file.c b/src/calendar/backends/file/e-cal-backend-file.c
index 0c89f2cef..3ce7b80e5 100644
--- a/src/calendar/backends/file/e-cal-backend-file.c
+++ b/src/calendar/backends/file/e-cal-backend-file.c
@@ -87,6 +87,9 @@ struct _ECalBackendFilePrivate {
        GMutex refresh_lock;
        /* set to TRUE to indicate thread should stop */
        gboolean refresh_thread_stop;
+       /* set to TRUE when the refresh thread is running;
+          it can happen that the refresh_cond is set, but the thread is gone */
+       gboolean refresh_thread_running;
        /* condition for refreshing, not NULL when thread exists */
        GCond *refresh_cond;
        /* cond to know the refresh thread gone */
@@ -977,15 +980,24 @@ refresh_thread_func (gpointer data)
 
        /* This returns a newly-created GFile. */
        file = e_source_local_dup_custom_file (extension);
-       g_return_val_if_fail (G_IS_FILE (file), NULL);
+       if (!file) {
+               g_mutex_lock (&priv->refresh_lock);
+               priv->refresh_thread_running = FALSE;
+               g_cond_signal (priv->refresh_gone_cond);
+               g_mutex_unlock (&priv->refresh_lock);
+
+               return NULL;
+       }
 
        info = g_file_query_info (
                file, G_FILE_ATTRIBUTE_TIME_MODIFIED,
                G_FILE_QUERY_INFO_NONE, NULL, NULL);
-       g_return_val_if_fail (info != NULL, NULL);
-
-       last_modified = g_file_info_get_attribute_uint64 (info, G_FILE_ATTRIBUTE_TIME_MODIFIED);
-       g_object_unref (info);
+       if (info) {
+               last_modified = g_file_info_get_attribute_uint64 (info, G_FILE_ATTRIBUTE_TIME_MODIFIED);
+               g_object_unref (info);
+       } else {
+               last_modified = 0;
+       }
 
        g_mutex_lock (&priv->refresh_lock);
        while (!priv->refresh_thread_stop) {
@@ -1025,6 +1037,7 @@ refresh_thread_func (gpointer data)
        }
 
        g_object_unref (file);
+       priv->refresh_thread_running = FALSE;
        g_cond_signal (priv->refresh_gone_cond);
        g_mutex_unlock (&priv->refresh_lock);
 
@@ -1090,6 +1103,7 @@ prepare_refresh_data (ECalBackendFile *cbfile)
 
                priv->refresh_cond = g_new0 (GCond, 1);
                priv->refresh_gone_cond = g_new0 (GCond, 1);
+               priv->refresh_thread_running = TRUE;
 
                thread = g_thread_new (NULL, refresh_thread_func, cbfile);
                g_thread_unref (thread);
@@ -1116,7 +1130,10 @@ free_refresh_data (ECalBackendFile *cbfile)
        if (priv->refresh_cond) {
                priv->refresh_thread_stop = TRUE;
                g_cond_signal (priv->refresh_cond);
-               g_cond_wait (priv->refresh_gone_cond, &priv->refresh_lock);
+
+               while (priv->refresh_thread_running) {
+                       g_cond_wait (priv->refresh_gone_cond, &priv->refresh_lock);
+               }
 
                g_cond_clear (priv->refresh_cond);
                g_free (priv->refresh_cond);