Fix language server not working with the latest beta

[david-driscoll]

This contains two fixes.

1. Fixed the problem where requests were not being routed correctly.
2. Adds an example folding range, to ensure that it works.
   

Also I've done a small refactor around ITextDocumentIdentifier previously this was only integrated in ITextDocumentSyncHandler, if you didn't register a ITextDocumentSyncHandler we would never catch any file registrations, because we would have way to identify a file.

I have left ITextDocumentIdentifier as a member of the ITextDocumentSyncHandler interface but I have added the ability to add your own ITextDocumentIdentifier instances, which will then be used when trying to identify files by Uri.

[david-driscoll]

This was why descriptors could not be found with the latest beta... I need to add an integration test with the LanguageServer for this at somepoint.

[david-driscoll]

This is the folding range in the gif attached.

[david-driscoll]

cc @mholo65 @TylerLeonhardt @tintoy

[david-driscoll]

Here are a few logs reference, you should see folding range in there.

Initialize should not return any static features

[Trace - 10:53:38 AM] Received response 'initialize - (0)' in 3991ms.
Result: {
    "capabilities": {
        "textDocumentSync": 0,
        "hoverProvider": false,
        "definitionProvider": false,
        "referencesProvider": false,
        "documentHighlightProvider": false,
        "documentSymbolProvider": false,
        "workspaceSymbolProvider": false,
        "documentFormattingProvider": false,
        "documentRangeFormattingProvider": false,
        "experimental": {}
    }
}

Registration (this should contain the folding range registration)

[Info  - 10:53:39 AM] Converting params for Notification initialized to OmniSharp.Extensions.LanguageServer.Protocol.Models.InitializedParams
[Trace - 10:53:39 AM] Received request 'client/registerCapability - (0)'.
Params: {
    "registrations": [
        {
            "id": "fa8256a9-3f00-410f-b940-d7aee4303371",
            "method": "textDocument/didChange",
            "registerOptions": {
                "syncKind": 1,
                "documentSelector": [
                    {
                        "pattern": "**/*.cs"
                    }
                ]
            }
        },
        {
            "id": "aa17d766-aeb5-4fd5-999d-1ef9f23e54bd",
            "method": "textDocument/didOpen",
            "registerOptions": {
                "documentSelector": [
                    {
                        "pattern": "**/*.cs"
                    }
                ]
            }
        },
        {
            "id": "6bb59ea1-11ca-4b49-8317-5f77baa62d05",
            "method": "textDocument/didClose",
            "registerOptions": {
                "documentSelector": [
                    {
                        "pattern": "**/*.cs"
                    }
                ]
            }
        },
        {
            "id": "4c884630-fa8e-4e30-8449-68230c54da52",
            "method": "textDocument/didSave",
            "registerOptions": {
                "includeText": true,
                "documentSelector": [
                    {
                        "pattern": "**/*.cs"
                    }
                ]
            }
        },
        {
            "id": "8fff9ed8-80e4-49d3-ae81-eef813b91a8c",
            "method": "workspace/didChangeWatchedFiles",
            "registerOptions": {}
        },
        {
            "id": "972a811e-4df5-4bcc-943f-e86345d08d37",
            "method": "textDocument/foldingRange",
            "registerOptions": {
                "documentSelector": [
                    {
                        "language": "csharp"
                    }
                ]
            }
        }
    ]
}

then you should see some folding range content in the logs later

[Info  - 10:53:50 AM] Handler Selected: SampleServer.FoldingRangeHandler via (null) (targeting OmniSharp.Extensions.JsonRpc.IJsonRpcRequestHandler`2[[OmniSharp.Extensions.LanguageServer.Protocol.Models.FoldingRangeRequestParam, OmniSharp.Extensions.LanguageProtocol, Version=0.0.9.9, Culture=neutral, PublicKeyToken=6d868dff454e6022],[OmniSharp.Extensions.LanguageServer.Protocol.Models.Container`1[[OmniSharp.Extensions.LanguageServer.Protocol.Models.FoldingRange, OmniSharp.Extensions.LanguageProtocol, Version=0.0.9.9, Culture=neutral, PublicKeyToken=6d868dff454e6022]], OmniSharp.Extensions.LanguageProtocol, Version=0.0.9.9, Culture=neutral, PublicKeyToken=6d868dff454e6022]])
[Trace - 10:53:50 AM] Received notification 'window/logMessage'.
Params: {
    "type": 3,
    "message": "Starting: Routing Request (2) textDocument/foldingRange"
}


[Info  - 10:53:50 AM] Starting: Routing Request (2) textDocument/foldingRange
[Trace - 10:53:50 AM] Received notification 'window/logMessage'.
Params: {
    "type": 3,
    "message": "Converting params for Request (2) textDocument/foldingRange to OmniSharp.Extensions.LanguageServer.Protocol.Models.FoldingRangeRequestParam"
}


[Info  - 10:53:50 AM] Converting params for Request (2) textDocument/foldingRange to OmniSharp.Extensions.LanguageServer.Protocol.Models.FoldingRangeRequestParam
[Trace - 10:53:50 AM] Received notification 'window/logMessage'.
Params: {
    "type": 3,
    "message": "Result was System.Threading.Tasks.Task`1[[OmniSharp.Extensions.LanguageServer.Protocol.Models.Container`1[[OmniSharp.Extensions.LanguageServer.Protocol.Models.FoldingRange, OmniSharp.Extensions.LanguageProtocol, Version=0.0.9.9, Culture=neutral, PublicKeyToken=6d868dff454e6022]], OmniSharp.Extensions.LanguageProtocol, Version=0.0.9.9, Culture=neutral, PublicKeyToken=6d868dff454e6022]]"
}


[Info  - 10:53:50 AM] Result was System.Threading.Tasks.Task`1[[OmniSharp.Extensions.LanguageServer.Protocol.Models.Container`1[[OmniSharp.Extensions.LanguageServer.Protocol.Models.FoldingRange, OmniSharp.Extensions.LanguageProtocol, Version=0.0.9.9, Culture=neutral, PublicKeyToken=6d868dff454e6022]], OmniSharp.Extensions.LanguageProtocol, Version=0.0.9.9, Culture=neutral, PublicKeyToken=6d868dff454e6022]]
[Trace - 10:53:50 AM] Received notification 'window/logMessage'.
Params: {
    "type": 3,
    "message": "Response value was OmniSharp.Extensions.LanguageServer.Protocol.Models.Container`1[[OmniSharp.Extensions.LanguageServer.Protocol.Models.FoldingRange, OmniSharp.Extensions.LanguageProtocol, Version=0.0.9.9, Culture=neutral, PublicKeyToken=6d868dff454e6022]]"
}


[Info  - 10:53:50 AM] Response value was OmniSharp.Extensions.LanguageServer.Protocol.Models.Container`1[[OmniSharp.Extensions.LanguageServer.Protocol.Models.FoldingRange, OmniSharp.Extensions.LanguageProtocol, Version=0.0.9.9, Culture=neutral, PublicKeyToken=6d868dff454e6022]]
[Trace - 10:53:50 AM] Received notification 'window/logMessage'.
Params: {
    "type": 3,
    "message": "Finished: Routing Request (2) textDocument/foldingRange in 0ms"
}


[Info  - 10:53:50 AM] Finished: Routing Request (2) textDocument/foldingRange in 0ms
[Trace - 10:53:50 AM] Received response 'textDocument/foldingRange - (2)' in 4ms.
Result: [
    {
        "startLine": 10,
        "startCharacter": 0,
        "endLine": 20,
        "endCharacter": 0,
        "kind": 2
    }
]

[TylerLeonhardt]

💯👌 Nice!