[Commonizer] Nicer API for CirProvidedClassifiers

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/facade.kt

@@ -41,9 +41,9 @@ private fun mergeAndCommonize(storageManager: StorageManager, parameters: Common
     val classifiers = CirKnownClassifiers(
         commonizedNodes = CirCommonizedClassifierNodes.default(),
         forwardDeclarations = CirForwardDeclarations.default(),
-        commonDependencies = CirCompositeClassifiers(
+        commonDependencies = CirProvidedClassifiers.of(
             CirFictitiousFunctionClassifiers,
-            CirLoadedClassifiers.from(parameters.dependencyModulesProvider)
+            CirProvidedClassifiers.by(parameters.dependencyModulesProvider)
         )
     )
     val mergeResult = CirTreeMerger(storageManager, classifiers, parameters).merge()

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/mergedtree/CirCompositeClassifiers.kt

@@ -1,14 +0,0 @@
-/*
- * 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.descriptors.commonizer.mergedtree
-
-import org.jetbrains.kotlin.descriptors.commonizer.cir.CirEntityId
-
-class CirCompositeClassifiers(private val delegates: List<CirProvidedClassifiers>) : CirProvidedClassifiers {
-    constructor(vararg delegates: CirProvidedClassifiers) : this(delegates.toList())
-
-    override fun hasClassifier(classifierId: CirEntityId): Boolean = delegates.any { it.hasClassifier(classifierId) }
-}

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/mergedtree/CirProvidedClassifiers.kt

@@ -0,0 +1,47 @@
+/*
+ * 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.descriptors.commonizer.mergedtree
+
+import org.jetbrains.kotlin.descriptors.commonizer.ModulesProvider
+import org.jetbrains.kotlin.descriptors.commonizer.cir.CirEntityId
+
+/** A set of classes and type aliases provided by libraries (either the libraries to commonize, or their dependency libraries)/ */
+interface CirProvidedClassifiers {
+    fun hasClassifier(classifierId: CirEntityId): Boolean
+
+    // TODO: implement later
+    //fun classifier(classifierId: ClassId): Any?
+
+    object EMPTY : CirProvidedClassifiers {
+        override fun hasClassifier(classifierId: CirEntityId) = false
+    }
+
+    private class CompositeClassifiers(val delegates: List<CirProvidedClassifiers>) : CirProvidedClassifiers {
+        override fun hasClassifier(classifierId: CirEntityId) = delegates.any { it.hasClassifier(classifierId) }
+    }
+
+    companion object {
+        fun of(vararg delegates: CirProvidedClassifiers): CirProvidedClassifiers {
+            val unwrappedDelegates: List<CirProvidedClassifiers> = delegates.fold(ArrayList()) { acc, delegate ->
+                when (delegate) {
+                    EMPTY -> Unit
+                    is CompositeClassifiers -> acc.addAll(delegate.delegates)
+                    else -> acc.add(delegate)
+                }
+                acc
+            }
+
+            return when (unwrappedDelegates.size) {
+                0 -> EMPTY
+                1 -> unwrappedDelegates.first()
+                else -> CompositeClassifiers(unwrappedDelegates)
+            }
+        }
+
+        fun by(modulesProvider: ModulesProvider?): CirProvidedClassifiers =
+            if (modulesProvider != null) CirProvidedClassifiersByModules(modulesProvider) else EMPTY
+    }
+}

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/mergedtree/CirProvidedClassifiersByModules.kt

@@ -14,15 +14,10 @@ import org.jetbrains.kotlin.library.metadata.parsePackageFragment
 import org.jetbrains.kotlin.metadata.ProtoBuf
 import org.jetbrains.kotlin.metadata.deserialization.NameResolverImpl
 
-class CirLoadedClassifiers(modulesProvider: ModulesProvider) : CirProvidedClassifiers {
+internal class CirProvidedClassifiersByModules(modulesProvider: ModulesProvider) : CirProvidedClassifiers {
     private val classifiers: Set<CirEntityId> = loadClassifiers(modulesProvider)
 
     override fun hasClassifier(classifierId: CirEntityId): Boolean = classifierId in classifiers
-
-    companion object {
-        fun from(modulesProvider: ModulesProvider?): CirProvidedClassifiers =
-            if (modulesProvider != null) CirLoadedClassifiers(modulesProvider) else CirProvidedClassifiers.EMPTY
-    }
 }
 
 private fun loadClassifiers(modulesProvider: ModulesProvider): Set<CirEntityId> {

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/mergedtree/classifierContainers.kt

@@ -67,18 +67,4 @@ interface CirForwardDeclarations {
             }
         }
     }
-}
-
-/** A set of classes and type aliases provided by libraries (either the libraries to commonize, or their dependency libraries)/ */
-interface CirProvidedClassifiers {
-    fun hasClassifier(classifierId: CirEntityId): Boolean
-
-    // TODO: implement later
-    //fun classifier(classifierId: ClassId): Any?
-
-    companion object {
-        internal val EMPTY = object : CirProvidedClassifiers {
-            override fun hasClassifier(classifierId: CirEntityId) = false
-        }
-    }
-}
+}