[evolution-data-server] [CalDAV] Be able to open in offline mode when VPN is down

[Milan Crha <mcrha src gnome org>]

commit d7030579928ac02d959c5480e58f529aa106918f
Author: Milan Crha <mcrha redhat com>
Date:   Wed Feb 25 15:11:44 2015 +0100

    [CalDAV] Be able to open in offline mode when VPN is down

 calendar/backends/caldav/e-cal-backend-caldav.c |   58 +++++++++++++++++++++-
 libebackend/e-backend.c                         |   27 +++++++++-
 2 files changed, 79 insertions(+), 6 deletions(-)
---
diff --git a/calendar/backends/caldav/e-cal-backend-caldav.c b/calendar/backends/caldav/e-cal-backend-caldav.c
index c0533c0..4e1693e 100644
--- a/calendar/backends/caldav/e-cal-backend-caldav.c
+++ b/calendar/backends/caldav/e-cal-backend-caldav.c
@@ -571,6 +571,8 @@ status_code_to_result (SoupMessage *message,
                return FALSE;
 
        switch (message->status_code) {
+       case SOUP_STATUS_CANT_RESOLVE:
+       case SOUP_STATUS_CANT_RESOLVE_PROXY:
        case SOUP_STATUS_CANT_CONNECT:
        case SOUP_STATUS_CANT_CONNECT_PROXY:
                g_propagate_error (
@@ -1197,6 +1199,8 @@ caldav_server_open_calendar (ECalBackendCalDAV *cbdav,
                e_source_set_connection_status (source, E_SOURCE_CONNECTION_STATUS_DISCONNECTED);
 
                switch (message->status_code) {
+               case SOUP_STATUS_CANT_RESOLVE:
+               case SOUP_STATUS_CANT_RESOLVE_PROXY:
                case SOUP_STATUS_CANT_CONNECT:
                case SOUP_STATUS_CANT_CONNECT_PROXY:
                        *server_unreachable = TRUE;
@@ -1545,6 +1549,8 @@ caldav_server_list_objects (ECalBackendCalDAV *cbdav,
        /* Check the result */
        if (message->status_code != SOUP_STATUS_MULTI_STATUS) {
                switch (message->status_code) {
+               case SOUP_STATUS_CANT_RESOLVE:
+               case SOUP_STATUS_CANT_RESOLVE_PROXY:
                case SOUP_STATUS_CANT_CONNECT:
                case SOUP_STATUS_CANT_CONNECT_PROXY:
                        cbdav->priv->opened = FALSE;
@@ -1669,6 +1675,8 @@ caldav_server_query_for_uid (ECalBackendCalDAV *cbdav,
        /* Check the result */
        if (message->status_code != SOUP_STATUS_MULTI_STATUS) {
                switch (message->status_code) {
+               case SOUP_STATUS_CANT_RESOLVE:
+               case SOUP_STATUS_CANT_RESOLVE_PROXY:
                case SOUP_STATUS_CANT_CONNECT:
                case SOUP_STATUS_CANT_CONNECT_PROXY:
                        cbdav->priv->opened = FALSE;
@@ -2572,14 +2580,35 @@ caldav_synch_slave_loop (gpointer data)
                }
 
                if (!cbdav->priv->opened) {
-                       if (open_calendar_wrapper (cbdav, NULL, NULL, TRUE, &know_unreachable, NULL, NULL)) {
+                       gchar *certificate_pem = NULL;
+                       GTlsCertificateFlags certificate_errors = 0;
+                       GError *local_error = NULL;
+
+                       if (open_calendar_wrapper (cbdav, NULL, &local_error, TRUE, &know_unreachable, 
&certificate_pem, &certificate_errors)) {
                                cbdav->priv->opened = TRUE;
                                update_slave_cmd (cbdav->priv, SLAVE_SHOULD_WORK);
                                g_cond_signal (&cbdav->priv->cond);
 
                                cbdav->priv->is_google = is_google_uri (cbdav->priv->uri);
                                know_unreachable = FALSE;
+                       } else {
+                               ESourceCredentialsReason reason = E_SOURCE_CREDENTIALS_REASON_REQUIRED;
+                               GError *local_error2 = NULL;
+
+                               if (g_error_matches (local_error, SOUP_HTTP_ERROR, SOUP_STATUS_SSL_FAILED)) {
+                                       reason = E_SOURCE_CREDENTIALS_REASON_SSL_FAILED;
+                               }
+
+                               if (!e_backend_credentials_required_sync (E_BACKEND (cbdav), reason, 
certificate_pem, certificate_errors,
+                                       local_error, NULL, &local_error2)) {
+                                       g_warning ("%s: Failed to call credentials required: %s", G_STRFUNC, 
local_error2 ? local_error2->message : "Unknown error");
+                               }
+
+                               g_clear_error (&local_error2);
                        }
+
+                       g_clear_error (&local_error);
+                       g_free (certificate_pem);
                }
 
                if (cbdav->priv->opened) {
@@ -2910,6 +2939,28 @@ initialize_backend (ECalBackendCalDAV *cbdav,
 }
 
 static gboolean
+caldav_was_ever_connected (ECalBackendCalDAV *cbdav)
+{
+       gboolean has_components;
+       GSList *uids;
+
+       g_return_val_if_fail (E_IS_CAL_BACKEND_CALDAV (cbdav), FALSE);
+
+       if (!cbdav->priv->store)
+               return FALSE;
+
+       uids = e_cal_backend_store_get_component_ids (cbdav->priv->store);
+
+       /* Assume the calendar was connected if it has any events stored;
+          obviously, empty calendars will fail this check. */
+       has_components = uids != NULL;
+
+       g_slist_free_full (uids, (GDestroyNotify) e_cal_component_free_id);
+
+       return has_components;
+}
+
+static gboolean
 open_calendar_wrapper (ECalBackendCalDAV *cbdav,
                       GCancellable *cancellable,
                       GError **error,
@@ -2951,8 +3002,9 @@ open_calendar_wrapper (ECalBackendCalDAV *cbdav,
                                g_clear_error (&local_error);
 
                                *know_unreachable = TRUE;
-                       } else {
-                               /* this allows to open the calendar in read-only mode */
+                       } else if (caldav_was_ever_connected (cbdav)) {
+                               /* This allows to open the calendar in read-only mode, which can be done
+                                  if it was ever connected to the server. */
                                g_clear_error (&local_error);
                                success = TRUE;
                        }
diff --git a/libebackend/e-backend.c b/libebackend/e-backend.c
index 1da8626..bdd682f 100644
--- a/libebackend/e-backend.c
+++ b/libebackend/e-backend.c
@@ -565,9 +565,30 @@ backend_get_destination_address (EBackend *backend,
                                  gchar **host,
                                  guint16 *port)
 {
-       /* default implementation returns FALSE, indicating
-        * no remote destination being used for this backend */
-       return FALSE;
+       GSocketConnectable *connectable;
+       GNetworkAddress *address;
+
+       g_return_val_if_fail (E_IS_BACKEND (backend), FALSE);
+       g_return_val_if_fail (host != NULL, FALSE);
+       g_return_val_if_fail (port != NULL, FALSE);
+
+       connectable = e_backend_ref_connectable (backend);
+       if (!connectable)
+               return FALSE;
+
+       if (!G_IS_NETWORK_ADDRESS (connectable)) {
+               g_object_unref (connectable);
+               return FALSE;
+       }
+
+       address = G_NETWORK_ADDRESS (connectable);
+
+       *host = g_strdup (g_network_address_get_hostname (address));
+       *port = g_network_address_get_port (address);
+
+       g_object_unref (connectable);
+
+       return *host != NULL;
 }
 
 static void