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.
Fixes https://github.com/sbt/sbt/issues/3112
This unpacks Extracted as State's extension methods.
In addition this provides a way of responding via LSP.
To demonstrate [-Yno-lub](http://eed3si9n.com/stricter-scala-with-ynolub), this shows the code changes that removes lubing (Not all subprojects are done).
After I made the changes, I switched the Scala back to normal 2.12.10.
This is an implementation of `textDocument/definition` request.
Supports types only, and only in case when type is found in Zinc Analysis. When source(s) are found then editor opens potential source(s).
This simple implementation does not use semantic data.
During the processing of `textDocument/didSave`, we will start collecting the location of Analysis files via `lspCollectAnalyses`.
Later on, when the user asked for `textDocument/definition`, sbt server will invoke a Future call to lspDefinition, which direct reads the files to locate the definition of a class.
This is the first cut for the Language Server Protocol on top of server that is still work in progress.
With this change, sbt is able to invoke `compile` task on saving files in VS Code.