[ObjCExport] Support nullable type arguments in translating known Collection types

^KT-65167

native/objcexport-header-generator/impl/analysis-api/src/org/jetbrains/kotlin/objcexport/translateToObjCMethod.kt

@@ -6,7 +6,6 @@ import com.intellij.openapi.util.io.FileUtil
 import org.jetbrains.kotlin.analysis.api.KtAnalysisSession
 import org.jetbrains.kotlin.analysis.api.annotations.annotationInfos
 import org.jetbrains.kotlin.analysis.api.symbols.*
-import org.jetbrains.kotlin.analysis.api.types.KtType
 import org.jetbrains.kotlin.backend.konan.InternalKotlinNativeApi
 import org.jetbrains.kotlin.backend.konan.KonanFqNames
 import org.jetbrains.kotlin.backend.konan.objcexport.*
@@ -14,7 +13,6 @@ import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.name.NameUtils
 import org.jetbrains.kotlin.objcexport.Predefined.anyMethodSelectors
 import org.jetbrains.kotlin.objcexport.analysisApiUtils.getFunctionMethodBridge
-import org.jetbrains.kotlin.objcexport.analysisApiUtils.getInlineTargetTypeOrNull
 import org.jetbrains.kotlin.objcexport.analysisApiUtils.isVisibleInObjC
 import org.jetbrains.kotlin.psi.KtFile
 
@@ -327,7 +325,7 @@ fun KtFunctionLikeSymbol.mapReturnType(returnBridge: MethodBridge.ReturnValue):
         MethodBridge.ReturnValue.Void,
         -> ObjCVoidType
         MethodBridge.ReturnValue.HashCode -> ObjCPrimitiveType.NSUInteger
-        is MethodBridge.ReturnValue.Mapped -> returnType.mapType(returnBridge.bridge)
+        is MethodBridge.ReturnValue.Mapped -> returnType.translateToObjCType(returnBridge.bridge)
         MethodBridge.ReturnValue.WithError.Success -> ObjCPrimitiveType.BOOL
         is MethodBridge.ReturnValue.WithError.ZeroForError -> {
             val successReturnType = mapReturnType(returnBridge.successBridge)
@@ -349,44 +347,3 @@ fun KtFunctionLikeSymbol.mapReturnType(returnBridge: MethodBridge.ReturnValue):
         -> ObjCInstanceType
     }
 }
-
-
-/**
- * [org.jetbrains.kotlin.backend.konan.objcexport.ObjCExportTranslatorImpl.mapType]
- */
-context(KtAnalysisSession, KtObjCExportSession)
-private fun KtType.mapType(typeBridge: TypeBridge): ObjCType {
-
-    //if (!this.isObjCObjectType()) return null //TODO implement isObjCObjectType
-
-    return when (typeBridge) {
-        is ReferenceBridge -> this.translateToObjCReferenceType()
-        is BlockPointerBridge -> this.translateToObjCFunctionType(typeBridge)
-        is ValueTypeBridge -> when (typeBridge.objCValueType) {
-            ObjCValueType.BOOL -> ObjCPrimitiveType.BOOL
-            ObjCValueType.UNICHAR -> ObjCPrimitiveType.unichar
-            ObjCValueType.CHAR -> ObjCPrimitiveType.int8_t
-            ObjCValueType.SHORT -> ObjCPrimitiveType.int16_t
-            ObjCValueType.INT -> ObjCPrimitiveType.int32_t
-            ObjCValueType.LONG_LONG -> ObjCPrimitiveType.int64_t
-            ObjCValueType.UNSIGNED_CHAR -> ObjCPrimitiveType.uint8_t
-            ObjCValueType.UNSIGNED_SHORT -> ObjCPrimitiveType.uint16_t
-            ObjCValueType.UNSIGNED_INT -> ObjCPrimitiveType.uint32_t
-            ObjCValueType.UNSIGNED_LONG_LONG -> ObjCPrimitiveType.uint64_t
-            ObjCValueType.FLOAT -> ObjCPrimitiveType.float
-            ObjCValueType.DOUBLE -> ObjCPrimitiveType.double
-            ObjCValueType.POINTER -> ObjCPointerType(ObjCVoidType, isBinaryRepresentationNullable())
-        }
-    }
-}
-
-context(KtAnalysisSession)
-private fun KtType.isBinaryRepresentationNullable(): Boolean {
-    if (fullyExpandedType.isMarkedNullable) return true
-
-    getInlineTargetTypeOrNull()?.let { inlineTargetType ->
-        if (inlineTargetType.isMarkedNullable) return true
-    }
-
-    return false
-}

native/objcexport-header-generator/impl/analysis-api/src/org/jetbrains/kotlin/objcexport/translateToObjCParameters.kt

@@ -42,7 +42,7 @@ internal fun KtFunctionLikeSymbol.translateToObjCParameters(baseMethodBridge: Me
 
         val type = when (bridge) {
             is MethodBridgeValueParameter.Mapped ->
-                parameter!!.returnType.translateToObjCReferenceType()
+                parameter!!.returnType.translateToObjCType(bridge.bridge)
             MethodBridgeValueParameter.ErrorOutParameter ->
                 ObjCPointerType(ObjCNullableReferenceType(ObjCClassType("NSError")), nullable = true)
 

native/objcexport-header-generator/impl/analysis-api/src/org/jetbrains/kotlin/objcexport/translateToObjCType.kt

@@ -8,10 +8,53 @@ import org.jetbrains.kotlin.backend.konan.objcexport.*
 import org.jetbrains.kotlin.builtins.StandardNames
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.name.StandardClassIds
 import org.jetbrains.kotlin.objcexport.analysisApiUtils.getInlineTargetTypeOrNull
 import org.jetbrains.kotlin.objcexport.analysisApiUtils.isError
 import org.jetbrains.kotlin.objcexport.analysisApiUtils.objCErrorType
 
+
+/**
+ * [org.jetbrains.kotlin.backend.konan.objcexport.ObjCExportTranslatorImpl.mapType]
+ */
+context(KtAnalysisSession, KtObjCExportSession)
+internal fun KtType.translateToObjCType(typeBridge: TypeBridge): ObjCType {
+
+    //if (!this.isObjCObjectType()) return null //TODO implement isObjCObjectType
+
+    return when (typeBridge) {
+        is ReferenceBridge -> this.translateToObjCReferenceType()
+        is BlockPointerBridge -> this.translateToObjCFunctionType(typeBridge)
+        is ValueTypeBridge -> when (typeBridge.objCValueType) {
+            ObjCValueType.BOOL -> ObjCPrimitiveType.BOOL
+            ObjCValueType.UNICHAR -> ObjCPrimitiveType.unichar
+            ObjCValueType.CHAR -> ObjCPrimitiveType.int8_t
+            ObjCValueType.SHORT -> ObjCPrimitiveType.int16_t
+            ObjCValueType.INT -> ObjCPrimitiveType.int32_t
+            ObjCValueType.LONG_LONG -> ObjCPrimitiveType.int64_t
+            ObjCValueType.UNSIGNED_CHAR -> ObjCPrimitiveType.uint8_t
+            ObjCValueType.UNSIGNED_SHORT -> ObjCPrimitiveType.uint16_t
+            ObjCValueType.UNSIGNED_INT -> ObjCPrimitiveType.uint32_t
+            ObjCValueType.UNSIGNED_LONG_LONG -> ObjCPrimitiveType.uint64_t
+            ObjCValueType.FLOAT -> ObjCPrimitiveType.float
+            ObjCValueType.DOUBLE -> ObjCPrimitiveType.double
+            ObjCValueType.POINTER -> ObjCPointerType(ObjCVoidType, isBinaryRepresentationNullable())
+        }
+    }
+}
+
+context(KtAnalysisSession)
+private fun KtType.isBinaryRepresentationNullable(): Boolean {
+    if (fullyExpandedType.isMarkedNullable) return true
+
+    getInlineTargetTypeOrNull()?.let { inlineTargetType ->
+        if (inlineTargetType.isMarkedNullable) return true
+    }
+
+    return false
+}
+
+
 /**
  * [org.jetbrains.kotlin.backend.konan.objcexport.ObjCExportTranslatorImpl.mapReferenceType]
  */
@@ -36,7 +79,7 @@ private fun KtType.mapToReferenceTypeIgnoringNullability(): ObjCNonNullReference
         return ObjCIdType
     }
 
-    if (classId in hiddenTypes) {
+    if (classId in hiddenClassIds) {
         return ObjCIdType
     }
 
@@ -76,18 +119,30 @@ private fun KtType.mapToReferenceTypeIgnoringNullability(): ObjCNonNullReference
     val typeName = typesMap[classId]
         ?: classId!!.shortClassName.asString().getObjCKotlinStdlibClassOrProtocolName().objCName
 
-    val typeArguments = run {
-        if (this !is KtNonErrorClassType) {
-            return@run listOf<ObjCNonNullReferenceType>()
-        }
-
-        ownTypeArguments.mapNotNull { typeArgument -> typeArgument.type }
-            .map { typeArgumentType -> typeArgumentType.mapToReferenceTypeIgnoringNullability() }
-    }
+    val typeArguments = translateToObjCTypeArguments()
 
     return ObjCClassType(typeName, typeArguments)
 }
 
+
+context(KtAnalysisSession, KtObjCExportSession)
+private fun KtType.translateToObjCTypeArguments(): List<ObjCNonNullReferenceType> {
+    if (this !is KtNonErrorClassType) return emptyList()
+
+    /* See special casing below */
+    val isKnownCollectionType = classId in collectionClassIds
+
+    return ownTypeArguments.mapNotNull { typeArgument -> typeArgument.type }
+        .map { typeArgumentType ->
+
+            /*
+             Kotlin `null` keys and values are represented as `NSNull` singleton in collections
+             */
+            if (isKnownCollectionType && typeArgumentType.isMarkedNullable) return@map ObjCIdType
+            typeArgumentType.mapToReferenceTypeIgnoringNullability()
+        }
+}
+
 private fun ObjCNonNullReferenceType.withNullabilityOf(kotlinType: KtType): ObjCReferenceType {
     return if (kotlinType.nullability.isNullable) {
         ObjCNullableReferenceType(this)
@@ -102,7 +157,7 @@ private fun ObjCNonNullReferenceType.withNullabilityOf(kotlinType: KtType): ObjC
  * Currently contains super types of classes handled by custom type mappers.
  * Note: can be generated programmatically, but requires stdlib in this case.
  */
-private val hiddenTypes: Set<ClassId> = listOf(
+private val hiddenClassIds: Set<ClassId> = listOf(
     "kotlin.Any",
     "kotlin.CharSequence",
     "kotlin.Comparable",
@@ -112,4 +167,10 @@ private val hiddenTypes: Set<ClassId> = listOf(
     "kotlin.collections.Iterable",
     "kotlin.collections.MutableCollection",
     "kotlin.collections.MutableIterable"
-).map { ClassId.topLevel(FqName(it)) }.toSet()
+).map { ClassId.topLevel(FqName(it)) }.toSet()
+
+private val collectionClassIds = setOf(
+    StandardClassIds.List, StandardClassIds.MutableList,
+    StandardClassIds.Set, StandardClassIds.MutableSet,
+    StandardClassIds.Map, StandardClassIds.MutableMap
+)