So, if I understand correctly, it would be:
boolean flipEcho;
and the readPassword would do something like:
if (echo0() != false) {
flipEcho = true;
echo(false);
}
....
if (flipEcho) { //this would also be in the shutdown hook
echo(!echo0());
}
I guess I can do that (the variant with two boolean feels to me slightly
easier to understand and a tiny bit more robust, but this flip boolean
variant is doable as well).
Thanks,
Jan
On 25.4.2018 21:07, Martin Buchholz wrote:
I keep hoping for something simpler.
Is it possible to have more than one Console object? Looks like NO.
Assuming no, then you simply need one static flag
boolean restoreEcho;
(it could also be an instance field of Console - that would be slightly
more principled)
In readPassword you check current value of echo and set restoreEcho if it
was changed. Shutdown hook also checks the same restoreEcho.
For bonus points, only create the shutdown hook the first time readPassword
is called with echo on to appease the Emacs shell users with pitchforks.
On Wed, Apr 25, 2018 at 9:34 AM, Xueming Shen <xueming.s...@oracle.com>
wrote:
On 4/25/18, 9:02 AM, Martin Buchholz wrote:
It would be more correct I think for Console to track if there is a
pending readPassword in progress and try to restore echo on exit only if
so. But a little annoying to implement (need an additional boolean?)
I think that is what Jan proposed "to add restoredEchoOnShutdown = true",
and I'm fine
with that. I'm just a little confused why jshell invokes System.console()
if it handles all "raw"
terminal stuff itself.
On Wed, Apr 25, 2018 at 8:52 AM, Xueming Shen <xueming.s...@oracle.com>
wrote:
Hi Jan,
I saw System.console() returns null inside jshell ... but it seems there
are 2 vms.
I would assume jshell itself sets the terminal to raw and then call
System.console()?
for example an alternative for this issue is to ask jshell's impl to call
System.console()
before going into raw mode? No, I'm not saying the proposed one is not a
good one,
just wanted to make sure I understand the situation correctly.
Thanks,
Sherman
On 4/25/18, 4:50 AM, Jan Lahoda wrote:
Hi,
Under:
https://bugs.openjdk.java.net/browse/JDK-8194750
j.i.Console was changed to capture the state of the terminal echo at
creation time, and to restore it on shutdown.
That is problematic at least in jshell, where the terminal is already in
the raw mode when j.i.Console is created, and so "echo disabled" is
recorded there. So even though jshell itself sets the terminal into the
original mode when it terminates, the shutdown hook in j.i.Console, which
is run later, sets the echo to off even if it was enabled before the VM
started.
My understanding is that the shutdown hook is only needed in case the VM
goes down while readPassword is running. So I tried to change the shutdown
hook to only work while readPassword is running.
Bug: https://bugs.openjdk.java.net/browse/JDK-8202105
Webrev: http://cr.openjdk.java.net/~jlahoda/8202105/webrev.00/
What do you think?
Thanks,
Jan
