Introduce ConcurrentMapBasedCache

analysis/analysis-internal-utils/src/org/jetbrains/kotlin/analysis/utils/collections/ConcurrentNullableMap.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.analysis.utils.collections
+
+import java.util.concurrent.ConcurrentMap
+
+public class ConcurrentMapBasedCache<K, V>(public val map: ConcurrentMap<K, Any>) {
+    public inline fun getOrPut(
+        key: K,
+        crossinline compute: (K) -> V?
+    ): V {
+        val value = map.getOrPut(key) { compute(key) ?: NullValue }
+        return value.nullValueToNull()
+    }
+}
+
+public object NullValue
+
+@Suppress("NOTHING_TO_INLINE", "UNCHECKED_CAST")
+public fun <V> Any.nullValueToNull(): V = when (this) {
+    NullValue -> null
+    else -> this
+} as V
+