Use constructor instead of putNextLink in LinkedValue and Links

Author: ilya-g

kotlinx-collections-immutable/src/main/kotlin/kotlinx/collections/immutable/implementations/persistentOrderedMap/PersistentOrderedMap.kt

@@ -25,20 +25,17 @@ import kotlinx.collections.immutable.mutate
 internal object EndOfChain
 
 internal class LinkedValue<V>(val value: V, val previous: Any?, val next: Any?) {
+    /** Constructs LinkedValue for a new single entry */
     constructor(value: V) : this(value, EndOfChain, EndOfChain)
+    /** Constructs LinkedValue for a new last entry */
+    constructor(value: V, previous: Any?) : this(value, previous, EndOfChain)
 
     fun withValue(newValue: V) = LinkedValue(newValue, previous, next)
     fun withPrevious(newPrevious: Any?) = LinkedValue(value, newPrevious, next)
     fun withNext(newNext: Any?) = LinkedValue(value, previous, newNext)
 
     val hasNext get() = next !== EndOfChain
     val hasPrevious get() = previous !== EndOfChain
-
-    // TODO: it doesn't use 'this', can be made static
-    fun putNextLink(value: V, previous: Any?): LinkedValue<V> {
-//        assert(next === EndOfChain)
-        return LinkedValue(value, previous, EndOfChain)
-    }
 }
 
 internal class PersistentOrderedMap<K, V>(
@@ -95,11 +92,11 @@ internal class PersistentOrderedMap<K, V>(
 
         @Suppress("UNCHECKED_CAST")
         val lastKey = lastKey as K
-        val lastLink = hashMap[lastKey]!!
+        val lastLinks = hashMap[lastKey]!!
 //        assert(!lastLink.hasNext)
         val newMap = hashMap
-                .put(lastKey, lastLink.withNext(key))
-                .put(key, lastLink.putNextLink(value, lastKey))
+                .put(lastKey, lastLinks.withNext(key))
+                .put(key, LinkedValue(value, previous = lastKey))
         return PersistentOrderedMap(firstKey, key, newMap)
     }
 

kotlinx-collections-immutable/src/main/kotlin/kotlinx/collections/immutable/implementations/persistentOrderedMap/PersistentOrderedMapBuilder.kt

@@ -77,11 +77,11 @@ internal class PersistentOrderedMapBuilder<K, V>(private var map: PersistentOrde
         }
         @Suppress("UNCHECKED_CAST")
         val lastKey = lastKey as K
-        val lastLink = hashMapBuilder[lastKey]!!
-        assert(!lastLink.hasNext)
+        val lastLinks = hashMapBuilder[lastKey]!!
+        assert(!lastLinks.hasNext)
 
-        hashMapBuilder[lastKey] = lastLink.withNext(key)
-        hashMapBuilder[key] = lastLink.putNextLink(value, lastKey)
+        hashMapBuilder[lastKey] = lastLinks.withNext(key)
+        hashMapBuilder[key] = LinkedValue(value, previous = lastKey)
         this.lastKey = key
         return null
     }

kotlinx-collections-immutable/src/main/kotlin/kotlinx/collections/immutable/implementations/persistentOrderedSet/PersistentOrderedSet.kt

@@ -22,18 +22,16 @@ import kotlinx.collections.immutable.implementations.persistentOrderedMap.EndOfC
 import kotlinx.collections.immutable.mutate
 
 internal class Links(val previous: Any?, val next: Any?) {
+    /** Constructs Links for a new single element */
     constructor() : this(EndOfChain, EndOfChain)
+    /** Constructs Links for a new last element */
+    constructor(previous: Any?) : this(previous, EndOfChain)
 
     fun withNext(newNext: Any?) = Links(previous, newNext)
     fun withPrevious(newPrevious: Any?) = Links(newPrevious, next)
 
     val hasNext get() = next !== EndOfChain
     val hasPrevious get() = previous !== EndOfChain
-
-    fun putNextLink(previous: Any?): Links {
-//        assert(next === EndOfChain)
-        return Links(previous, next)
-    }
 }
 
 internal class PersistentOrderedSet<E>(
@@ -61,7 +59,7 @@ internal class PersistentOrderedSet<E>(
 
         val newMap = hashMap
                 .put(lastElement, lastLinks.withNext(element))
-                .put(element, lastLinks.putNextLink(lastElement))
+                .put(element, Links(previous = lastElement))
         return PersistentOrderedSet(firstElement, element, newMap)
     }
 

kotlinx-collections-immutable/src/main/kotlin/kotlinx/collections/immutable/implementations/persistentOrderedSet/PersistentOrderedSetBuilder.kt

@@ -57,7 +57,7 @@ internal class PersistentOrderedSetBuilder<E>(private var set: PersistentOrdered
         val lastLinks = hashMapBuilder[lastElement]!!
 //        assert(lastLinks.next === EndOfLink)
         hashMapBuilder[lastElement as E] = lastLinks.withNext(element)
-        hashMapBuilder[element] = lastLinks.putNextLink(lastElement)
+        hashMapBuilder[element] = Links(previous = lastElement)
         lastElement = element
 
         return true