From 59e3a9e23cb2e81cb1a5ffd044b57538b3071e6c Mon Sep 17 00:00:00 2001
From: Edoardo La Greca
Date: Wed, 6 Aug 2025 21:41:38 +0200
Subject: add FIDInfo

---
 src/main/kotlin/Connection.kt |  4 ++--
 src/main/kotlin/FIDInfo.kt    | 42 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 2 deletions(-)
 create mode 100644 src/main/kotlin/FIDInfo.kt

diff --git a/src/main/kotlin/Connection.kt b/src/main/kotlin/Connection.kt
index 6444ade..b916d1b 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
 
     /**
-     * Each FID associated with each file.
+     * Info about FIDs.
      */
-    val fids: Map<UInt, String> = emptyMap()
+    val fids: FIDInfo = FIDInfo()
 
     // 9P constants.
     val DEFAULT_VERSION = "9P2000"
diff --git a/src/main/kotlin/FIDInfo.kt b/src/main/kotlin/FIDInfo.kt
new file mode 100644
index 0000000..dbbc945
--- /dev/null
+++ b/src/main/kotlin/FIDInfo.kt
@@ -0,0 +1,42 @@
+/**
+ * This class holds all info about File IDs (FIDs).
+ */
+class FIDInfo() {
+    private val inUse: MutableSet<FID> = mutableSetOf()
+
+    /**
+     * A single FID.
+     *
+     * @param fid The actual FID value.
+     * @param path The path of the FID, represented as successive path name elements.
+     * @param qid The QID associated with the FID.
+     */
+    data class FID(val fid: UInt, val path: List<String>, val qid: QID)
+
+    /**
+     * Add a FID with the associated file path and QID.
+     */
+    fun addFID(fid: FID) {
+        this.inUse.add(fid)
+    }
+
+    /**
+     * Find the path associated to a FID.
+     *
+     * @param fid The FID to find the path of.
+     * @return The path if [fid] could be found, or null otherwise.
+     */
+    fun findPathByFID(fid: UInt): List<String>? {
+        return this.inUse.find { x -> x.fid == fid }?.path
+    }
+
+    /**
+     * Find the FID associated to a path.
+     *
+     * @param path The path to find the FID of.
+     * @return The FID if [path] has an associated FID, or null otherwise.
+     */
+    fun findFIDByPath(path: List<String>): UInt? {
+        return this.inUse.find { x -> x.path == path }?.fid
+    }
+}
\ No newline at end of file
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