change checkedInMessage to throw exceptions instead of returning errors

1 files changed, 11 insertions, 11 deletions

diff --git a/src/main/kotlin/Connection.kt b/src/main/kotlin/Connection.kt
index 1cef2d3..48394e0 100644
--- a/src/main/kotlin/Connection.kt
+++ b/src/main/kotlin/Connection.kt
@@ -51,25 +51,25 @@ class Connection(transLay: TransportLayer) : ProtocolTranslator {
     }
 
     /**
-     * Handy function to create an [InMessage] instance and check for errors. It uses [tl] and [maxSize] for instancing
-     * the [InMessage] class.
+     * Handy function to create an [InMessage] instance and check for errors. After successfully using this function, it
+     * is guaranteed that both no error occurred while reading the incoming message and the message is not of type
+     * R-error.
+     *
+     * It uses [tl] and [maxSize] for instancing the [InMessage] class.
      *
      * @return A pair of: (1) a nullable string (which can be: `null` if no error occurred, empty if an error occurred
      * with no message, or non-empty with the error message) and (2) the optional [InMessage] instance (null if an error
      * occurred).
+     * @throws InvalidMessageException if the received message is invalid.
+     * @throws RErrorException if the received message is an R-error message.
      */
-    private fun checkedInMessage(reqTag: UShort): Pair<String?, InMessage?> {
-        val imsg: InMessage
-        try {
-            imsg = InMessage(this.tl, this.maxSize, reqTag)
-        } catch (ime: InvalidMessageException) {
-            return Pair(ime.message!!, null)
-        }
+    private fun checkedInMessage(reqTag: UShort): InMessage {
+        val imsg = InMessage(this.tl, this.maxSize, reqTag)
         if (imsg.type == NinePMessageType.RERROR) {
             imsg.applyField(InMessage.Field("ename", InMessage.Field.Type.STRING, 0u))
-            return Pair(imsg.fieldsStr["ename"]!!, null)
+            throw RErrorException(imsg.fieldsStr["ename"])
         }
-        return Pair(null, imsg)
+        return imsg
     }
 
     override fun version(msize: UInt, version: String): String? {