emerge: Implement "--alert"

Implement "--alert" (short option "-A"), which adds a terminal bell
character ('\a') to all prompts, when it is set to True or "y". It may
be used without an option, like e.g. --ask, to mean True.

The patch refactors userquery to a class, UserQuery, to accommodate
--alert. It also adds the option to the emerge man page.

A quick example is to do 'emerge -PAc portage'.

If you have your terminal emulator set up to make '\a' into a window
manager urgency hint, move your cursor to a different window to get the
effect. 'sleep 2 && emerge' is another way to test this.

The --alert option is especially useful if you, like me, tend to fire up
a big world update when you get to the office in the morning (or night),
and then immediately change your focus to something else. If you now do
'emerge -auAD world', emerge will courteously point out when it has
finished calculating the graph, and again when it has finished emerging.

Signed-off-by: Alexander Berntsen <bernalex@gentoo.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/man/emerge.1 b/man/emerge.1
index abb0ed898..bbcf569e2 100644
--- a/man/emerge.1
+++ b/man/emerge.1
@@ -297,6 +297,11 @@ re\-distributable. With default
 configuration, this would result in an effective
 \fBACCEPT_RESTRICT\fR value of "* -bindist".
 .TP
+.BR "\-\-alert "
+Add a terminal bell character ('\\a') to all interactive prompts. This is
+especially useful if dependency resolution is taking a long time, and
+you want emerge to alert you when it is finished.
+.TP
 .BR "\-\-alphabetical "
 When displaying USE and other flag output, combines the enabled and
 disabled lists into one list and sorts the whole list alphabetically.