change read to use exceptions instead of error strings

2 files changed, 7 insertions, 10 deletions

diff --git a/src/main/kotlin/Connection.kt b/src/main/kotlin/Connection.kt
index cb93533..984b345 100644
--- a/src/main/kotlin/Connection.kt
+++ b/src/main/kotlin/Connection.kt
@@ -190,7 +190,7 @@ class Connection(transLay: TransportLayer) : ProtocolTranslator {
         TODO("Not yet implemented")
     }
 
-    override fun read(fid: UInt, offset: ULong, count: UInt): Pair<String?, Array<UByte>> {
+    override fun read(fid: UInt, offset: ULong, count: UInt): Array<UByte> {
         val omsg = OutMessage(NinePMessageType.TREAD, this.tagGen.generate(), listOf("fid", "offset", "count"),
             mapOf(
                 "fid" to BigInteger(fid.toString()),
@@ -202,16 +202,12 @@ class Connection(transLay: TransportLayer) : ProtocolTranslator {
             this.maxSize
         )
         omsg.write(this.tl)
-        val checkErr = checkedInMessage(omsg.tag)
-        if (checkErr.first != null) {
-            return Pair(checkErr.first, emptyArray())
-        }
-        val imsg = checkErr.second!!
+        val imsg = checkedInMessage(omsg.tag)
         imsg.applyField(InMessage.Field("count", InMessage.Field.Type.INTEGER, 4u))
         val count = imsg.fieldsInt["count"]!!.toInt().toUInt()
         imsg.applyField(InMessage.Field("data", InMessage.Field.Type.RAW, count))
 
-        return Pair(null, imsg.fieldsRaw["data"]!!)
+        return imsg.fieldsRaw["data"]!!
     }
 
     override fun write(fid: UInt, offset: ULong, count: UInt, data: Iterable<UByte>): Pair<String?, UInt> {
diff --git a/src/main/kotlin/ProtocolTranslator.kt b/src/main/kotlin/ProtocolTranslator.kt
index bf29131..b0f02c3 100644
--- a/src/main/kotlin/ProtocolTranslator.kt
+++ b/src/main/kotlin/ProtocolTranslator.kt
@@ -87,10 +87,11 @@ interface ProtocolTranslator {
      * Transfer data from file. Due to the negotiated maximum size of 9P messages, called `msize`, one is supposed to
      * call this method multiple times, unless the content is smaller than `msize`.
      *
-     * @return A pair of: (1) an optional error message and (2) the content read with the call just made. If the string
-     * is not null, an error occurred and the array is going to be empty.
+     * @return The content read with the call just made.
+     * @throws except.InvalidMessageException if the received message is invalid.
+     * @throws except.RErrorException if the received message is an R-error message.
      */
-    fun read(fid: UInt, offset: ULong, count: UInt): Pair<String?, Array<UByte>>
+    fun read(fid: UInt, offset: ULong, count: UInt): Array<UByte>
 
     /**
      * Transfer data to file. Due to the negotiated maximum size of 9P messages, called `msize`, one is supposed to