This commit makes it possible for the sbt server to render the same ui
to multiple clients. The network client ui should look nearly identical
to the console ui except for the log messages about the experimental
client.
The way that it works is that it associates a ui thread with each
terminal. Whenever a command starts or completes, callbacks are invoked
on the various channels to update their ui state. For example, if there
are two clients and one of them runs compile, then the prompt is changed
from AskUser to Running for the terminal that initiated the command
while the other client remains in the AskUser state. Whenever the client
changes uses ui states, the existing thread is terminated if it is
running and a new thread is begun.
The UITask formalizes this process. It is based on the AskUser class
from older versions of sbt. In fact, there is an AskUserTask which is
very similar. It uses jline to read input from the terminal (which could
be a network terminal). When it gets a line, it submits it to the
CommandExchange and exits. Once the next command is run (which may or
may not be the command it submitted), the ui state will be reset.
The debug, info, warn and error commands should work with the multi
client ui. When run, they set the log level globally, not just for the
client that set the level.
Prior to this change, the server test was repeatedly performing io on
the portfile while the server was starting up. This adds a modest sleep
so that the test is just as responsive without doing needless io.
Initial draft for bsp support.
This shows two communication pattern around BSP.
First, if the request can be handled with the build knowledge is readily available in `NetworkChannel` we can reply immediately. `BuildServerImpl#onBspBuildTargets` is an example for that.
Second, if the request requires `State`, then we can forward the parameter into a custom command, and reply back from a command. `BuildServerProtocol.bspBuildTargetSources` is an example of that since it needs to invoke tasks to generate sources.
Ethan Atkins
Eugene Yokota
Adrien Piquerez