[evolution-ews] I#41 - Unreachable EWS service causes Calendar(s) to disappear

[Milan Crha <mcrha src gnome org>]

commit 78dfcc9b1182352d7ccf3d87f0f45590cb63757f
Author: Milan Crha <mcrha redhat com>
Date:   Mon Mar 18 21:30:05 2019 +0100

    I#41 - Unreachable EWS service causes Calendar(s) to disappear
    
    Closes https://gitlab.gnome.org/GNOME/evolution-ews/issues/41

 src/collection/e-ews-backend.c | 117 +++++++++++++++++++++++++++++++++--------
 1 file changed, 94 insertions(+), 23 deletions(-)
---
diff --git a/src/collection/e-ews-backend.c b/src/collection/e-ews-backend.c
index 74cea1d8..45201a44 100644
--- a/src/collection/e-ews-backend.c
+++ b/src/collection/e-ews-backend.c
@@ -56,6 +56,7 @@ struct _SyncFoldersClosure {
        GSList *folders_created;
        GSList *folders_deleted;
        GSList *folders_updated;
+       GHashTable *old_sources; /* gchar *folder_id ~> ESource * */
 };
 
 G_DEFINE_DYNAMIC_TYPE (
@@ -77,6 +78,8 @@ sync_folders_closure_free (SyncFoldersClosure *closure)
        /* List of EEwsFolder instances. */
        g_slist_free_full (closure->folders_updated, g_object_unref);
 
+       g_hash_table_destroy (closure->old_sources);
+
        g_slice_free (SyncFoldersClosure, closure);
 }
 
@@ -373,7 +376,8 @@ ews_backend_new_address_book (EEwsBackend *backend,
 
 static void
 ews_backend_sync_created_folders (EEwsBackend *backend,
-                                  GSList *list)
+                                 GSList *list,
+                                 GHashTable *old_sources)
 {
        ECollectionBackend *collection_backend;
        ESourceRegistryServer *server;
@@ -391,8 +395,10 @@ ews_backend_sync_created_folders (EEwsBackend *backend,
                fid = e_ews_folder_get_id (folder);
                if (!fid || !fid->id)
                        continue;  /* not a valid ID anyway */
-               if (ews_backend_folders_contains (backend, fid->id))
+               if (ews_backend_folders_contains (backend, fid->id)) {
+                       g_hash_table_remove (old_sources, fid->id);
                        continue;
+               }
 
                switch (e_ews_folder_get_folder_type (folder)) {
                        case E_EWS_FOLDER_TYPE_CALENDAR:
@@ -417,6 +423,9 @@ ews_backend_sync_created_folders (EEwsBackend *backend,
 
                if (source != NULL) {
                        e_source_registry_server_add_source (server, source);
+
+                       g_hash_table_remove (old_sources, fid->id);
+
                        g_object_unref (source);
                }
        }
@@ -426,7 +435,8 @@ ews_backend_sync_created_folders (EEwsBackend *backend,
 
 static void
 ews_backend_sync_deleted_folders (EEwsBackend *backend,
-                                  GSList *list)
+                                 GSList *list,
+                                 GHashTable *old_sources)
 {
        GSList *link;
 
@@ -434,9 +444,10 @@ ews_backend_sync_deleted_folders (EEwsBackend *backend,
                const gchar *folder_id = link->data;
                ESource *source = NULL;
 
-               if (folder_id != NULL)
-                       source = ews_backend_folders_lookup (
-                               backend, folder_id);
+               if (folder_id) {
+                       source = ews_backend_folders_lookup (backend, folder_id);
+                       g_hash_table_remove (old_sources, folder_id);
+               }
 
                if (source == NULL)
                        continue;
@@ -581,21 +592,22 @@ ews_backend_source_changed_cb (ESource *source,
 }
 
 static void
-add_remote_sources (EEwsBackend *backend)
+add_remote_sources (EEwsBackend *backend,
+                   GHashTable *old_sources)
 {
-       GList *old_sources, *iter;
+       GHashTableIter iter;
        ESourceRegistryServer *registry;
        const gchar *extension_name;
+       gpointer value;
 
        registry = e_collection_backend_ref_server (
                E_COLLECTION_BACKEND (backend));
-       old_sources = e_collection_backend_claim_all_resources (
-               E_COLLECTION_BACKEND (backend));
 
        extension_name = E_SOURCE_EXTENSION_EWS_FOLDER;
 
-       for (iter = old_sources; iter; iter = iter->next) {
-               ESource *source = iter->data;
+       g_hash_table_iter_init (&iter, old_sources);
+       while (g_hash_table_iter_next (&iter, NULL, &value)) {
+               ESource *source = value;
                ESourceEwsFolder *extension;
 
                if (!e_source_has_extension (source, extension_name))
@@ -622,7 +634,6 @@ add_remote_sources (EEwsBackend *backend)
                }
        }
 
-       g_list_free_full (old_sources, g_object_unref);
        g_object_unref (registry);
 }
 
@@ -634,11 +645,11 @@ ews_backend_sync_folders_idle_cb (gpointer user_data)
        /* FIXME Handle updated folders. */
 
        ews_backend_sync_deleted_folders (
-               closure->backend, closure->folders_deleted);
+               closure->backend, closure->folders_deleted, closure->old_sources);
        ews_backend_sync_created_folders (
-               closure->backend, closure->folders_created);
+               closure->backend, closure->folders_created, closure->old_sources);
 
-       add_remote_sources (closure->backend);
+       add_remote_sources (closure->backend, closure->old_sources);
 
        return FALSE;
 }
@@ -796,6 +807,7 @@ ews_backend_populate (ECollectionBackend *backend)
                return;
 
        ews_backend_add_gal_source (ews_backend);
+       ews_backend_claim_old_resources (backend);
 
        if (e_backend_get_online (E_BACKEND (backend))) {
                CamelEwsSettings *ews_settings;
@@ -809,8 +821,6 @@ ews_backend_populate (ECollectionBackend *backend)
                                E_SOURCE_CREDENTIALS_REASON_REQUIRED, NULL, 0, NULL,
                                NULL, NULL);
                }
-       } else {
-               ews_backend_claim_old_resources (backend);
        }
 }
 
@@ -1393,6 +1403,60 @@ ews_backend_forget_all_sources (EEwsBackend *backend)
        g_list_free_full (sources, g_object_unref);
 }
 
+static void
+ews_backend_fill_known_sources (EEwsBackend *backend,
+                               GHashTable *known_sources) /* gchar *folder_id ~> ESource * */
+{
+       ECollectionBackend *collection_backend;
+       CamelEwsSettings *settings;
+       GList *sources, *link;
+       gchar *gal_source_uid;
+
+       g_return_if_fail (E_IS_EWS_BACKEND (backend));
+       g_return_if_fail (known_sources != NULL);
+
+       settings = ews_backend_get_settings (backend);
+       gal_source_uid = camel_ews_settings_dup_gal_uid (settings);
+
+       collection_backend = E_COLLECTION_BACKEND (backend);
+
+       sources = e_collection_backend_list_calendar_sources (collection_backend);
+       for (link = sources; link; link = g_list_next (link)) {
+               ESource *source = link->data;
+
+               if (e_source_has_extension (source, E_SOURCE_EXTENSION_EWS_FOLDER)) {
+                       ESourceEwsFolder *extension;
+                       gchar *folder_id;
+
+                       extension = e_source_get_extension (source, E_SOURCE_EXTENSION_EWS_FOLDER);
+                       folder_id = e_source_ews_folder_dup_id (extension);
+                       if (folder_id)
+                               g_hash_table_insert (known_sources, folder_id, g_object_ref (source));
+               }
+       }
+       g_list_free_full (sources, g_object_unref);
+
+       sources = e_collection_backend_list_contacts_sources (collection_backend);
+       for (link = sources; link; link = g_list_next (link)) {
+               ESource *source = link->data;
+
+               /* Do not include GAL in known sources, there is always at least one */
+               if ((!gal_source_uid || g_strcmp0 (gal_source_uid, e_source_get_uid (source)) != 0) &&
+                   e_source_has_extension (source, E_SOURCE_EXTENSION_EWS_FOLDER)) {
+                       ESourceEwsFolder *extension;
+                       gchar *folder_id;
+
+                       extension = e_source_get_extension (source, E_SOURCE_EXTENSION_EWS_FOLDER);
+                       folder_id = e_source_ews_folder_dup_id (extension);
+                       if (folder_id)
+                               g_hash_table_insert (known_sources, folder_id, g_object_ref (source));
+               }
+       }
+       g_list_free_full (sources, g_object_unref);
+
+       g_free (gal_source_uid);
+}
+
 gboolean
 e_ews_backend_sync_folders_sync (EEwsBackend *backend,
                                  GCancellable *cancellable,
@@ -1465,25 +1529,32 @@ e_ews_backend_sync_folders_sync (EEwsBackend *backend,
 
        if (success) {
                SyncFoldersClosure *closure;
+               gboolean had_sync_state;
 
                /* This takes ownership of the folder lists. */
                closure = g_slice_new0 (SyncFoldersClosure);
                closure->backend = g_object_ref (backend);
+               closure->old_sources = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, 
g_object_unref);
                closure->folders_created = folders_created;
                closure->folders_deleted = folders_deleted;
                closure->folders_updated = folders_updated;
 
+               g_mutex_lock (&backend->priv->sync_state_lock);
+               had_sync_state = backend->priv->sync_state && *(backend->priv->sync_state);
+
+               g_free (backend->priv->sync_state);
+               backend->priv->sync_state = g_strdup (new_sync_state);
+               g_mutex_unlock (&backend->priv->sync_state_lock);
+
+               if (!had_sync_state)
+                       ews_backend_fill_known_sources (backend, closure->old_sources);
+
                /* Process the results from an idle callback. */
                g_idle_add_full (
                        G_PRIORITY_DEFAULT_IDLE,
                        ews_backend_sync_folders_idle_cb, closure,
                        (GDestroyNotify) sync_folders_closure_free);
 
-               g_mutex_lock (&backend->priv->sync_state_lock);
-               g_free (backend->priv->sync_state);
-               backend->priv->sync_state = g_strdup (new_sync_state);
-               g_mutex_unlock (&backend->priv->sync_state_lock);
-
        } else {
                /* Make sure we're not leaking anything. */
                g_warn_if_fail (folders_created == NULL);