plen+cooked_cursor==cols => begin = -1 which is passed to substr. The
sign is incorrect as code should be removing a character from begin
instead of trying to add a character.
I noticed that multibyte characters can mess up the console state
variables. I decided to add a minimal multibyte support to make sure the
input only collects complete valid multibyte characters in case user
enters them to console.
This change assumes that UTF-32 has one to one mapping between printed
characters and char32 indexes. But I remember reading there is a few
rare corner cases with accents where character might require multiple
4byte characters too. But this patch at least changes correct handling
from about 100 characters to 99% of unicode characters.
There is a minor chance that console or init thread would access already
freed memory when core is shutting down and cleaning up state. To avoid
any danger of having random bugs caused by the potential data race I
decided to make sure the shutdown code waits for the thread to exit
first.
Windows change is completely untested. It is purely based on msdn
documentation.