Added getDocumentSymbols call to extension API

[omusil24]

Hello everyone,

at Qore Technologies we are working on a VSCode extension and in it we need support for finding symbols in Java files. Adding a whole language server in it and supporting it would be way too much work, especially since your extension already has everything we need. There just wasn't a way to call the language server you are using from outside the extension.

This PR adds function getDocumentSymbols to the extension API, which can then be called by other extensions. This function performs textDocument/documentSymbol call to the language server and returns a promise with the result.

If you have any questions just ask, or if this PR has incorrect style etc. then I can fix that, no problem.

Signed-off-by: Ondřej Musil [email protected]

[omusil24]

@testforstephen I fixed the issues that you pointed out but suddenly the calls started to fail with the following response error:

ResponseError: Message could not be parsed.

code: -32700

Object {message: "java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 74 path $.params"}

"Error: Message could not be parsed.
	at handleResponse (/home/omusil/.vscode/extensions/redhat.java-0.54.0/node_modules/vscode-languageserver-protocol/node_modules/vscode-jsonrpc/lib/main.js:448:48)
	at processMessageQueue (/home/omusil/.vscode/extensions/redhat.java-0.54.0/node_modules/vscode-languageserver-protocol/node_modules/vscode-jsonrpc/lib/main.js:275:17)
	at Immediate.setImmediate (/home/omusil/.vscode/extensions/redhat.java-0.54.0/node_modules/vscode-languageserver-protocol/node_modules/vscode-jsonrpc/lib/main.js:259:13)
	at runCallback (timers.js:694:18)
	at tryOnImmediate (timers.js:665:5)
	at processImmediate (timers.js:647:5)"

Any idea what could be causing this? Is it maybe a bug in the language server? Cause I'm calling the function exactly the same way like before with same parameters, but now with the DocumentSymbolRequest from vscode-languageclient and the token added.

[omusil24]

Actually, now it's working fine. Just had to put in a check for undefined CancellationToken. After that it started working.

[testforstephen]

Looks good to me.

[omusil24]

@testforstephen is there anything else that I need to do? Or when will this get merged?

[fbricon]

@omusil24 thanks for your contribution, keep 'em coming!