Error handling: Fit to the spec and complete message if needed

A parameter is added to Tumbler's internal error signals to account for
the error domain, and the error code `TUMBLER_ERROR_OTHER_ERROR_DOMAIN`
is added to indicate that the error originated from a third-party API.

When sending the error signal via D-Bus, cancelling errors are filtered
out, and when the error originates from a third-party API, the error
message is prefixed with the domain and code of that error, in a
possibly parsable format.

Fixes #49.

1 files changed, 1 insertions, 0 deletions

diff --git a/tumbler/tumbler-thumbnailer.h b/tumbler/tumbler-thumbnailer.h
index 285626e..b983d4e 100644
--- a/tumbler/tumbler-thumbnailer.h
+++ b/tumbler/tumbler-thumbnailer.h
@@ -50,6 +50,7 @@ struct _TumblerThumbnailerIface
                       const gchar        *uri);
   void (*error)      (TumblerThumbnailer *thumbnailer,
                       const gchar        *failed_uri,
+                      GQuark              error_domain,
                       gint                error_code,
                       const gchar        *message);
   void (*unregister) (TumblerThumbnailer *thumbnailer);