1 files changed, 93 insertions, 0 deletions
diff --git a/lib/src/main/kotlin/PathInfo.kt b/lib/src/main/kotlin/PathInfo.kt
new file mode 100644
index 0000000..2aee406
--- /dev/null
+++ b/lib/src/main/kotlin/PathInfo.kt
@@ -0,0 +1,93 @@
+/**
+ * This class holds all info about paths, their FIDs, and their QIDs.
+ */
+class PathInfo() {
+    private val paths: MutableSet<Path> = mutableSetOf()
+
+    /**
+     * Information about a path. Each FID maps to one path but not all paths have FIDs (injective). On the other hand,
+     * one QID can be shared with different paths and FIDs.
+     *
+     * FIDs are optional because some R-messages only return QIDs for certain files (e.g. walk).
+     *
+     * @param path The path.
+     * @param fid The optional FID associated with the path.
+     * @param qid The QID associated with the path.
+     */
+    data class Path(val path: List<String>, val fid: UInt?, val qid: QID)
+
+    /**
+     * Add a path.
+     */
+    fun addPath(path: Path) {
+        this.paths.add(path)
+    }
+
+    /**
+     * Add a QID to an existing FID. Do nothing if the given FID does not exist.
+     */
+    fun addQIDToFID(fid: UInt, qid: QID) {
+        findByFID(fid)?.qid = qid
+    }
+
+    /**
+     * Remove a FID.
+     */
+    fun removeFID(fid: UInt) {
+        this.paths.removeIf { x -> x.fid == fid }
+    }
+
+    fun find(predicate: (Path) -> Boolean) = this.paths.find(predicate)
+
+    /**
+     * Find [Path] object by path.
+     *
+     * @param path The path to search for.
+     * @return A path object if [path] exists, or null otherwise.
+     */
+    fun findByPath(path: List<String>): Path? {
+        return this.paths.find { x -> x.path == path }
+    }
+
+    /**
+     * Find [Path] object by FID.
+     *
+     * @param fid The FID to search for.
+     * @return A path object if [fid] exists, or null otherwise.
+     */
+    fun findByFID(fid: UInt): Path? {
+        return this.paths.find { x -> x.fid == fid }
+    }
+
+    /**
+     * Find [Path] object by QID.
+     *
+     * @param qid The path to search for.
+     * @return A path object if [qid] exists, or null otherwise.
+     */
+    fun findByQID(qid: QID): Path? {
+        return this.paths.find { x -> x.qid == qid }
+    }
+
+    /**
+     * Retrieve all paths
+     */
+    fun getAllPaths(): Set<Path> {
+        return this.paths.toSet()
+    }
+
+    /**
+     * Generate a new FID which is not already in use.
+     *
+     * @return The new FID.
+     * @throws IllegalStateException if there is no available FID.
+     */
+    fun genFID(): UInt {
+        for (newFid in 0u..UInt.MAX_VALUE) {
+            if (findByFID(newFid) == null) {
+                return newFid
+            }
+        }
+        throw IllegalStateException()
+    }
+}
+\ No newline at end of file