[gnome-software/gnome-3-24] snap: Better handle cancel errors

[Robert Ancell <rancell src gnome org>]

commit 0e39f143d566eb8a8ace7d7eb29316c60290db98
Author: Robert Ancell <robert ancell canonical com>
Date:   Fri Oct 27 16:23:05 2017 +1300

    snap: Better handle cancel errors

 plugins/snap/gs-snapd.c |   65 +++++++++++++++++++++++++---------------------
 1 files changed, 35 insertions(+), 30 deletions(-)
---
diff --git a/plugins/snap/gs-snapd.c b/plugins/snap/gs-snapd.c
index 8057ac3..022268e 100644
--- a/plugins/snap/gs-snapd.c
+++ b/plugins/snap/gs-snapd.c
@@ -684,8 +684,10 @@ send_package_action (const gchar *macaroon,
        g_autofree gchar *response = NULL;
        g_autofree gchar *status = NULL;
        g_autoptr(JsonParser) parser = NULL;
-       JsonObject *root, *result;
+       JsonObject *root;
        const gchar *type;
+       const gchar *change_id;
+       gboolean aborted = FALSE;
 
        content = g_strdup_printf ("{\"action\": \"%s\"}", action);
        path = g_strdup_printf ("/v2/snaps/%s", name);
@@ -719,43 +721,46 @@ send_package_action (const gchar *macaroon,
 
        root = json_node_get_object (json_parser_get_root (parser));
        type = json_object_get_string_member (root, "type");
+       if (g_strcmp0 (type, "async") != 0) {
+               g_set_error (error,
+                            GS_PLUGIN_ERROR,
+                            GS_PLUGIN_ERROR_NOT_SUPPORTED,
+                            "snapd operation returned unexpected type '%s'", type);
+               return FALSE;
+       }
+       change_id = json_object_get_string_member (root, "change");
 
-       if (g_strcmp0 (type, "async") == 0) {
-               const gchar *change_id;
-
-               change_id = json_object_get_string_member (root, "change");
+       while (TRUE) {
+               g_autoptr(JsonObject) result = NULL;
 
-               while (TRUE) {
-                       if (g_cancellable_is_cancelled (cancellable)) {
-                               result = abort_change (macaroon, discharges, change_id, NULL, error);
-                        }
-                       else {
-                               /* Wait for a little bit before polling */
-                               g_usleep (100 * 1000);
-
-                               result = get_change (macaroon, discharges, change_id, NULL, error);
-                       }
-                       if (result == NULL)
-                               return FALSE;
+               if (g_cancellable_is_cancelled (cancellable) && !aborted) {
+                       result = abort_change (macaroon, discharges, change_id, NULL, error);
+                       aborted = TRUE;
+               }
+               else {
+                       /* Wait for a little bit before polling */
+                       g_usleep (100 * 1000);
+                       result = get_change (macaroon, discharges, change_id, NULL, error);
+               }
+               if (result == NULL)
+                       return FALSE;
 
-                       status = g_strdup (json_object_get_string_member (result, "status"));
+               callback (result, user_data);
 
-                       if (g_strcmp0 (status, "Done") == 0)
-                               break;
+               if (!json_object_get_boolean_member (result, "ready"))
+                       continue;
 
-                       callback (result, user_data);
+               if (json_object_has_member (result, "err")) {
+                       g_set_error (error,
+                                    GS_PLUGIN_ERROR,
+                                    GS_PLUGIN_ERROR_NOT_SUPPORTED,
+                                    "snapd operation finished with error: %s",
+                                    json_object_get_string_member (result, "err"));
+                       return FALSE;
                }
-       }
 
-       if (g_strcmp0 (status, "Done") != 0) {
-               g_set_error (error,
-                            GS_PLUGIN_ERROR,
-                            GS_PLUGIN_ERROR_NOT_SUPPORTED,
-                            "snapd operation finished with status %s", status);
-               return FALSE;
+               return TRUE;
        }
-
-       return TRUE;
 }
 
 gboolean