This patch adds support for iterating through a const list. This allows
users of lists to be more rigid with regard to constness. Furthermore,
the patch adds the function 'List::insert_at' for inserting an element
at a specified position. By adding this function, we can remove code
duplication in nitpicker.
With this patch, the 'Signal_receiver::dissolve()' function does not return
as long as the signal context to be dissolved is still referenced by one
or more 'Signal' objects. This is supposed to delay the destruction of the
signal context while it is still in use.
Fixes#594.
Several users of the signal API used custom convenience classes to
invoke signal-handling functions on the reception of incoming signals.
The 'Signal_dispatcher' pattern turned out to be particularly useful. To
avoid the duplication of this code across the code base, this patch
adds the interface to 'base/signal.h'.
Furthermore, the patch changes the 'Signal::num()' return type from int
to unsigned because negative numbers are meaningless here.
Fixes#511
We cannot trust signal imprints received with signals to represent valid
pointers to signal contexts. After a signal context has been dissolved
from its receiver, a signal corresponding to the context might still be
in flight. Hence, we need a facility to check received signal imprints
against the list of valid contexts at reception time. The new
'Signal_context_registry' is a very simple attempt to create such a
facility.
Properly account signal count in the explicit-reply path (when source-
client gets immediately unblocked by 'signal_session_component::submit').
This patch prevents the delivery of superfluous signals with num == 0.