add checkedInMessage

1 files changed, 22 insertions, 0 deletions

diff --git a/src/main/kotlin/Connection.kt b/src/main/kotlin/Connection.kt
index 203b5e2..e0b7f18 100644
--- a/src/main/kotlin/Connection.kt
+++ b/src/main/kotlin/Connection.kt
@@ -50,6 +50,28 @@ class Connection(transLay: TransportLayer) : ProtocolTranslator {
         this.tl.close()
     }
 
+    /**
+     * Handy function to create an [InMessage] instance and check for errors. 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).
+     */
+    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)
+        }
+        if (imsg.type == NinePMessageType.RERROR) {
+            imsg.applyField(InMessage.Field("ename", InMessage.Field.Type.STRING, 0u))
+            return Pair(imsg.fieldsStr["ename"]!!, null)
+        }
+        return Pair(null, imsg)
+    }
+
     override fun version(msize: UInt, version: String): String? {
         val omsg = OutMessage(NinePMessageType.TVERSION, this.NOTAG, listOf("msize", "version"),
             mapOf(