From 7b49a4c587eaaee3d071ad12aaeb54ac302d06fa Mon Sep 17 00:00:00 2001
From: Edoardo La Greca
Date: Thu, 7 Aug 2025 17:27:53 +0200
Subject: add walk and change fids to pathInfo in Connection

---
 src/main/kotlin/Connection.kt | 51 ++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 46 insertions(+), 5 deletions(-)

diff --git a/src/main/kotlin/Connection.kt b/src/main/kotlin/Connection.kt
index b308402..13b928d 100644
--- a/src/main/kotlin/Connection.kt
+++ b/src/main/kotlin/Connection.kt
@@ -31,9 +31,9 @@ class Connection(transLay: TransportLayer) : ProtocolTranslator {
     private var maxSize: UInt = 0u
 
     /**
-     * Info about FIDs.
+     * Info about remote paths.
      */
-    val fids: FIDInfo = FIDInfo()
+    val pathInfo: PathInfo = PathInfo()
 
     // 9P constants.
     val DEFAULT_VERSION = "9P2000"
@@ -115,11 +115,52 @@ class Connection(transLay: TransportLayer) : ProtocolTranslator {
     }
 
     override fun attach() {
-        TODO("Not yet implemented")
+
     }
 
-    override fun walk(path: String) {
-        TODO("Not yet implemented")
+    override fun walk(fid: UInt, newfid: UInt, wname: List<String>): String? {
+        val nwname = wname.size
+        val omsg = OutMessage(NinePMessageType.TWALK, this.tagGen.generate(), listOf("fid", "newfid", "nwname"),
+            mapOf(
+                "fid" to BigInteger(fid.toString()),
+                "newfid" to BigInteger(newfid.toString()),
+                "nwname" to BigInteger(nwname.toString())
+            ),
+            emptyMap(),
+            emptyMap(),
+            this.maxSize
+        )
+        omsg.write(this.tl)
+        for (wn in wname) { // write wname elements
+            OutMessage.writeString(this.tl, wn)
+        }
+        val checkErr = checkedInMessage(omsg.tag)
+        if (checkErr.first != null) {
+            return checkErr.first
+        }
+        val imsg = checkErr.second!!
+
+        imsg.applyField(InMessage.Field("nwqid", InMessage.Field.Type.INTEGER, 2u))
+        val nwqid = imsg.fieldsInt["nwqid"]!!.toInt()
+        if (nwqid < nwname) {
+            return "cannot access ${wname.slice(0..nwqid).joinToString(separator = "/")}"
+        }
+        imsg.applyField(InMessage.Field("qids", InMessage.Field.Type.RAW, (nwqid * 13).toUInt()))
+        val rawQids = imsg.fieldsRaw["qids"]!!
+        val qids: MutableList<QID> = mutableListOf()
+        for (i in 0..<nwqid/13) {
+            val start = i * 13
+            val end = ((i+1) * 13) - 1
+            val rawQid = rawQids.slice(start..end)
+            qids += QID(rawQid)
+        }
+
+        for (i in 0..<nwname) {
+            this.pathInfo.addPath(PathInfo.Path(wname.slice(0..<i), null, qids[i]))
+        }
+        this.pathInfo.removeFID(fid)
+        this.pathInfo.addPath(PathInfo.Path(wname, newfid, qids.last()))
+        return null
     }
 
     override fun open(path: String) {
-- 
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