adding LSP rcp error codes

rpc.go

@@ -0,0 +1,51 @@
+package protocol
+
+// Range of the LSP code space
+const (
+	LspReservedErrorRangeStart = -32899
+	LspReservedErrorRangeEnd   = -32800
+)
+
+// LSP Specific error codes used with JSON RPC.
+const (
+	// Error code indicating that a server received a notification or
+	// request before the server received the `initialize` request.
+	//
+	// For backwards compatibility these codes are not in the LSP range.
+	RPCServerNotInitialized int64 = -32002
+	RPCUnknownErrorCode     int64 = -32001
+
+	// A request failed but it was syntactically correct, e.g the
+	// method name was known and the parameters were valid. The error
+	// message should contain human readable information about why
+	// the request failed.
+	//
+	// @since 3.17.0
+	RPCRequestFailed int64 = -32803
+
+	// The server detected that the content of a document got
+	// modified outside normal conditions. A server should
+	// NOT send this error code if it detects a content change
+	// in its unprocessed messages. The result even computed
+	// on an older state might still be useful for the client.
+	//
+	// If a client decides that a result is not of any use anymore
+	// the client should cancel the request.
+	RPCContentModified int64 = -32801
+
+	// The client has canceled a request and a server has detected
+	// the cancel.
+	RPCRequestCancelled int64 = -32800
+)
+
+func IsLspRPCErrorCode(code int64) bool {
+	if code >= LspReservedErrorRangeStart && code <= LspReservedErrorRangeEnd {
+		return true
+	}
+
+	if code == RPCServerNotInitialized || code == RPCUnknownErrorCode {
+		return true
+	}
+
+	return false
+}