Fix the map-seq and hash-set to return nil

Author: codeboost

src/xitdb/hash_map.clj

@@ -57,8 +57,7 @@
 
   clojure.lang.Seqable
   (seq [this]
-    (when (pos? (operations/map-item-count rhm))
-      (map-seq rhm)))
+    (map-seq rhm))
 
   clojure.lang.IFn
   (invoke [this k]
@@ -163,8 +162,7 @@
 
   clojure.lang.Seqable
   (seq [this]
-    (when (pos? (operations/map-item-count whm))
-      (map-seq whm)))
+    (map-seq whm))
 
   clojure.core.protocols/IKVReduce
   (kv-reduce [this f init]

src/xitdb/hash_set.clj

@@ -42,8 +42,7 @@
 
   clojure.lang.Seqable
   (seq [this]
-    (when (pos? (operations/set-item-count rhs))
-      (set-seq rhs)))
+    (set-seq rhs))
 
   clojure.lang.ILookup
   (valAt [this k]
@@ -119,8 +118,7 @@
 
   clojure.lang.Seqable
   (seq [this]
-    (when (pos? (operations/set-item-count whs))
-      (set-seq whs)))
+    (set-seq whs))
 
   clojure.lang.ILookup
   (valAt [this k]

src/xitdb/util/operations.clj

@@ -197,31 +197,33 @@
 ;; ============================================================================
 
 (defn map-seq
-  "Return a lazy seq of key-value MapEntry pairs."
+  "Return a lazy seq of key-value MapEntry pairs, or nil if empty."
   [^ReadHashMap rhm read-from-cursor]
   (let [it (.iterator rhm)]
-    (letfn [(step []
-              (lazy-seq
-                (when (.hasNext it)
-                  (let [cursor (.next it)
-                        kv     (.readKeyValuePair cursor)
-                        k      (read-from-cursor (.-keyCursor kv))]
-                    (let [v (read-from-cursor (.-valueCursor kv))]
-                      (cons (clojure.lang.MapEntry. k v) (step)))))))]
-      (step))))
+    (when (.hasNext it)
+      (letfn [(step []
+                (lazy-seq
+                  (when (.hasNext it)
+                    (let [cursor (.next it)
+                          kv     (.readKeyValuePair cursor)
+                          k      (read-from-cursor (.-keyCursor kv))]
+                      (let [v (read-from-cursor (.-valueCursor kv))]
+                        (cons (clojure.lang.MapEntry. k v) (step)))))))]
+        (step)))))
 
 (defn set-seq
-  "Return a lazy seq values from the set."
+  "Return a lazy seq values from the set, or nil if empty."
   [rhm read-from-cursor]
   (let [it (.iterator rhm)]
-    (letfn [(step []
-              (lazy-seq
-                (when (.hasNext it)
-                  (let [cursor (.next it)
-                        kv     (.readKeyValuePair cursor)
-                        v      (read-from-cursor (.-keyCursor kv))]
-                    (cons v (step))))))]
-      (step))))
+    (when (.hasNext it)
+      (letfn [(step []
+                (lazy-seq
+                  (when (.hasNext it)
+                    (let [cursor (.next it)
+                          kv     (.readKeyValuePair cursor)
+                          v      (read-from-cursor (.-keyCursor kv))]
+                      (cons v (step))))))]
+        (step)))))
 
 (defn array-seq
   "Creates a lazy sequence from a ReadArrayList.