[FIR] Introduce new Visibility class which not depends on descriptors

compiler/fir/cones/src/org/jetbrains/kotlin/fir/Visibilities.kt

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2010-2020 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.fir
+
+object Visibilities {
+    object PRIVATE : Visibility("private", isPublicAPI = false)
+
+    object PRIVATE_TO_THIS : Visibility("private_to_this", isPublicAPI = false) {
+        override val internalDisplayName: String
+            get() = "private/*private to this*/"
+    }
+
+    object PROTECTED : Visibility("protected", isPublicAPI = true)
+    object INTERNAL : Visibility("internal", isPublicAPI = false)
+    object PUBLIC : Visibility("public", isPublicAPI = true)
+    object LOCAL : Visibility("local", isPublicAPI = false)
+    object INVISIBLE_FAKE : Visibility("invisible_fake", isPublicAPI = false)
+    object UNKNOWN : Visibility("unknown", isPublicAPI = false)
+
+    @OptIn(ExperimentalStdlibApi::class)
+    private val ORDERED_VISIBILITIES: Map<Visibility, Int> = buildMap {
+        put(PRIVATE_TO_THIS, 0)
+        put(PRIVATE, 0);
+        put(INTERNAL, 1);
+        put(PROTECTED, 1);
+        put(PUBLIC, 2);
+    }
+
+    fun compare(first: Visibility, second: Visibility): Int? {
+        val result = first.compareTo(second)
+        if (result != null) {
+            return result
+        }
+        val oppositeResult = second.compareTo(first)
+        return if (oppositeResult != null) {
+            -oppositeResult
+        } else null
+    }
+
+    internal fun compareLocal(first: Visibility, second: Visibility): Int? {
+        if (first === second) return 0
+        val firstIndex = ORDERED_VISIBILITIES[first]
+        val secondIndex = ORDERED_VISIBILITIES[second]
+        return if (firstIndex == null || secondIndex == null || firstIndex == secondIndex) {
+            null
+        } else firstIndex - secondIndex
+    }
+
+    fun isPrivate(visibility: Visibility): Boolean {
+        return visibility === PRIVATE || visibility === PRIVATE_TO_THIS
+    }
+
+    val DEFAULT_VISIBILITY = PUBLIC
+}

compiler/fir/cones/src/org/jetbrains/kotlin/fir/Visibility.kt

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2010-2020 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.fir
+
+abstract class Visibility protected constructor(
+    val name: String,
+    val isPublicAPI: Boolean
+) {
+    open val internalDisplayName: String
+        get() = name
+
+    final override fun toString() = internalDisplayName
+
+    open fun compareTo(visibility: Visibility): Int? {
+        return Visibilities.compareLocal(this, visibility)
+    }
+
+    open fun normalize(): Visibility = this
+}
+