Don't rely on exceptions when parsing

Author: keynmol

core/src/jsonrpclib/CallId.scala

@@ -1,6 +1,7 @@
 package jsonrpclib
 
 import com.github.plokhotnyuk.jsoniter_scala.core._
+import scala.annotation.switch
 
 sealed trait CallId
 object CallId {
@@ -10,17 +11,13 @@ object CallId {
 
  implicit val callIdRW: JsonValueCodec[CallId] = new JsonValueCodec[CallId] {
  def decodeValue(in: JsonReader, default: CallId): CallId = {
- try {
- NumberId(in.readLong())
- } catch {
- case _: JsonReaderException =>
- in.rollbackToken()
- try {
- StringId(in.readString(null))
- } catch {
- case _: JsonReaderException =>
- in.readNullOrError(default, "expected null")
- }
+ val nt = in.nextToken()
+
+ (nt: @switch) match {
+ case 'n' => in.readNullOrError(default, "expected null")
+ case '"' => in.rollbackToken(); StringId(in.readString(null))
+ case _ => in.rollbackToken(); NumberId(in.readLong())
+
  }
  }