jsonrpc2: add initial jsonrpc2 package

Author: zchee

jsonrpc2.go

@@ -0,0 +1,94 @@
+// Copyright 2019 The go-language-server Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package jsonrpc2
+
+import (
+	"encoding/json"
+)
+
+// ID is a Request identifier.
+// Only one of either the Name or Number members will be set, using the
+// number form if the Name is the empty string.
+type ID struct {
+	Name   string
+	Number int64
+}
+
+// Message is a general message as defined by JSON-RPC. The language server protocol always uses "2.0" as the jsonrpc version.
+type Message struct {
+	JSONRPC string `json:"jsonrpc"`
+}
+
+// Request is a request message to describe a request between the client and the server. Every processed request must send a response back to the sender of the request.
+type Request struct {
+	Message
+
+	// The request id.
+	ID *ID `json:"id"`
+
+	// The method to be invoked.
+	Method string `json:"method"`
+
+	// The method's params.
+	Params *json.RawMessage `json:"params,omitempty"`
+}
+
+// Response is a response ressage sent as a result of a request. If a request doesn't provide a result value the receiver of a request still needs to return a response message to conform to the JSON RPC specification. The result property of the ResponseMessage should be set to null in this case to signal a successful request.
+type Response struct {
+	Message
+
+	// The error object in case a request fails.
+	Error *ResponseError `json:"error,omitempty"`
+
+	// The request id.
+	ID *ID `json:"id"`
+
+	// The result of a request. This member is REQUIRED on success.
+	// This member MUST NOT exist if there was an error invoking the method.
+	Result *json.RawMessage `json:"result,omitempty"`
+}
+
+// ResponseError ...
+type ResponseError struct {
+
+	// Code a number indicating the error type that occurred.
+	Code ErrorCode `json:"code"`
+
+	// Data a Primitive or Structured value that contains additional
+	// information about the error. Can be omitted.
+	Data *json.RawMessage `json:"data"`
+
+	// Message a string providing a short description of the error.
+	Message string `json:"message"`
+}
+
+type NotificationMessage struct {
+	Message
+
+	// Method is the method to be invoked.
+	Method string `json:"method"`
+
+	// Params is the notification's params.
+	Params interface{} `json:"params,omitempty"`
+}
+
+type ErrorCode int
+
+const (
+	// Defined by JSON RPC
+	ParseError           ErrorCode = -32700
+	InvalidRequest       ErrorCode = -32600
+	MethodNotFound       ErrorCode = -32601
+	InvalidParams        ErrorCode = -32602
+	InternalError        ErrorCode = -32603
+	ServerErrorStart     ErrorCode = -32099
+	ServerErrorEnd       ErrorCode = -32000
+	ServerNotInitialized ErrorCode = -32002
+	UnknownErrorCode     ErrorCode = -32001
+
+	// Defined by the protocol.
+	RequestCancelled ErrorCode = -32800
+	ContentModified  ErrorCode = -32801
+)