Add a GCancellable to EActivity.

EActivity now uses a GCancellable to manage cancellations, instead of
having its own redundant cancellation API.  API changes are as follows:

  + e_activity_get_cancellable()
  + e_activity_set_cancellable()

  - e_activity_cancel()
  - e_activity_is_cancelled()
  - e_activity_get_allow_cancel()
  - e_activity_set_allow_cancel()

EActivity's "cancelled" signal remains, but only as a repeater for
GCancellable::cancelled signals.  It should not be emitted directly.

The presence of a GCancellable implies that cancellation is allowed.
EActivity does not create its own default GCancellable, it has to be
given one.

If a CamelOperation (cast as a GCancellable) is given, EActivity will
configure itself to listen for status updates from the CamelOperation
and propagate the information to its own "primary-text" and "percent"
properties.

These changes allowed me to start cleaning up some of the incredibly
convoluted logic in mail-mt.c -- in particular, mail_operation_status()
is completely gone now.  mail-mt.c is still in a transitional state --
much more significant changes coming soon.

1 files changed, 4 insertions, 6 deletions

diff --git a/e-util/e-activity.h b/e-util/e-activity.h
index b396e3a630..4573fada57 100644
--- a/e-util/e-activity.h
+++ b/e-util/e-activity.h
@@ -65,18 +65,16 @@ struct _EActivityClass {
 };
 
 GType		e_activity_get_type		(void);
-EActivity *	e_activity_new			(const gchar *primary_text);
+EActivity *	e_activity_new			(void);
 EActivity *	e_activity_newv			(const gchar *format,
 						 ...) G_GNUC_PRINTF (1, 2);
-void		e_activity_cancel		(EActivity *activity);
 void		e_activity_complete		(EActivity *activity);
 void		e_activity_clicked		(EActivity *activity);
 gchar *		e_activity_describe		(EActivity *activity);
-gboolean	e_activity_is_cancelled		(EActivity *activity);
 gboolean	e_activity_is_completed		(EActivity *activity);
-gboolean	e_activity_get_allow_cancel	(EActivity *activity);
-void		e_activity_set_allow_cancel	(EActivity *activity,
-						 gboolean allow_cancel);
+GCancellable *	e_activity_get_cancellable	(EActivity *activity);
+void		e_activity_set_cancellable	(EActivity *activity,
+						 GCancellable *cancellable);
 gboolean	e_activity_get_clickable	(EActivity *activity);
 void		e_activity_set_clickable	(EActivity *activity,
 						 gboolean clickable);