Implement basic SkieVisibility configuration.

SKIE/common/configuration/annotations/src/commonMain/kotlin/co/touchlab/skie/configuration/annotations/SkieVisibility.kt

@@ -0,0 +1,75 @@
+package co.touchlab.skie.configuration.annotations
+
+/**
+ * Configures visibility of the exported Kotlin declarations in Swift.
+ * In the future, the visibility will be applied directly to the Obj-C header meaning it will also affect external Obj-C code.
+ *
+ * Note: Using multiple visibility annotations on the same declaration results in an undefined behavior, and may result in a compilation crash.
+ *
+ * Warning: SKIE does not check whether the configured visibility is correct or not.
+ * For example, it's possible to create a public interface with internal members.
+ * Invalid configurations will likely lead to weird issues and compiler crashes.
+ * In the future, SKIE might introduce explicit checks that will crash the compilation explicitly in those cases.
+ */
+@Target
+annotation class SkieVisibility {
+
+    /**
+     * The declaration will be visible from external modules as usual.
+     */
+    @Retention(AnnotationRetention.BINARY)
+    @Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY, AnnotationTarget.CONSTRUCTOR)
+    annotation class Public
+
+    /**
+     * The declaration will be visible from external modules, but it will be marked as `swift-private`.
+     * (Xcode will not include it in autocomplete suggestions.)
+     */
+    @Retention(AnnotationRetention.BINARY)
+    @Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY, AnnotationTarget.CONSTRUCTOR)
+    annotation class PublicButHidden
+
+    /**
+     * The declaration will be visible from external modules, but it will be:
+     *  - marked as `swift-private` (Xcode will not include it in autocomplete suggestions.),
+     *  - renamed in Swift by adding the `__` prefix (Obj-C name remains the same)
+     */
+    @Retention(AnnotationRetention.BINARY)
+    @Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY)
+    annotation class PublicButReplaced
+
+    /**
+     * The declaration will be visible only for declarations within the Kotlin module (including custom Swift code bundled by SKIE).
+     */
+    @Retention(AnnotationRetention.BINARY)
+    @Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY, AnnotationTarget.CONSTRUCTOR)
+    annotation class Internal
+
+    /**
+     * The declaration will be visible only for declarations within the Kotlin module (including custom Swift code bundled by SKIE).
+     * Additionally, the declaration will be renamed in Swift by adding the `__` prefix (Obj-C name remains the same)
+     */
+    @Retention(AnnotationRetention.BINARY)
+    @Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY)
+    annotation class InternalAndReplaced
+
+    /**
+     * The declaration will either be Public or Internal.
+     * Which one is chosen depends on whether the declaration is automatically wrapped by SKIE or not.
+     *
+     * For example, a top-level function originally exposed as `FileKt.functionName` will be internal, if SKIE generated the global function wrapper for it.
+     */
+    @Retention(AnnotationRetention.BINARY)
+    @Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY, AnnotationTarget.CONSTRUCTOR)
+    annotation class InternalIfWrapped
+
+    /**
+     * The declaration will not be visible.
+     *
+     * Note that this doesn't change whether the declaration is exported by the Kotlin compiler, therefore the compilation overhead from the exported declaration remains unchanged.
+     */
+    @Retention(AnnotationRetention.BINARY)
+    @Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY, AnnotationTarget.CONSTRUCTOR)
+    annotation class Private
+}
+

SKIE/common/configuration/api/src/commonMain/kotlin/co/touchlab/skie/configuration/ConfigurationKey.kt

@@ -36,11 +36,11 @@ interface ConfigurationKey<T> {
 
     interface NonOptional<T : Any> : ConfigurationKey<T> {
 
+        fun findAnnotationValue(configurationTarget: ConfigurationTarget): T? = null
+
         override fun hasAnnotationValue(configurationTarget: ConfigurationTarget): kotlin.Boolean =
             findAnnotationValue(configurationTarget) != null
 
-        fun findAnnotationValue(configurationTarget: ConfigurationTarget): T? = null
-
         override fun getAnnotationValue(configurationTarget: ConfigurationTarget): T =
             findAnnotationValue(configurationTarget)
                 ?: throw IllegalStateException("Target $configurationTarget does not have an annotation value.")
@@ -74,4 +74,15 @@ interface ConfigurationKey<T> {
         override fun deserialize(value: kotlin.String?): java.nio.file.Path =
             Path(value.throwIfNull())
     }
+
+    interface Enum<E : kotlin.Enum<E>> : NonOptional<E> {
+
+        override fun deserialize(value: kotlin.String?): E =
+            valueOf(value.throwIfNull())
+
+        override fun serialize(value: E): kotlin.String? =
+            value.name
+
+        fun valueOf(value: kotlin.String): E
+    }
 }

SKIE/common/configuration/api/src/commonMain/kotlin/co/touchlab/skie/configuration/ConfigurationTarget.kt

@@ -4,7 +4,7 @@ import kotlin.reflect.KClass
 
 interface ConfigurationTarget {
 
-    fun <T : Annotation> hasAnnotation(kClass: KClass<T>): Boolean
+    fun hasAnnotation(kClass: KClass<out Annotation>): Boolean
 
     fun <T : Annotation> findAnnotation(kClass: KClass<T>): T?
 }

SKIE/common/configuration/declaration/src/commonMain/kotlin/co/touchlab/skie/configuration/SkieVisibility.kt

@@ -0,0 +1,69 @@
+package co.touchlab.skie.configuration
+
+import co.touchlab.skie.configuration.annotations.SkieVisibility
+import kotlin.reflect.KClass
+
+/**
+ * Configures visibility of the exported Kotlin declarations in Swift.
+ * In the future, the visibility will be applied directly to the Obj-C header meaning it will also affect external Obj-C code.
+ *
+ * Warning: SKIE does not check whether the configured visibility is correct or not.
+ * For example, it's possible to create a public interface with internal members.
+ * Invalid configurations will likely lead to weird issues and compiler crashes.
+ * In the future, SKIE might introduce explicit checks that will crash the compilation explicitly in those cases.
+ */
+object SkieVisibility : ConfigurationKey.Enum<co.touchlab.skie.configuration.SkieVisibility.Level>, ConfigurationScope.All {
+
+    enum class Level(internal val associatedAnnotation: KClass<out Annotation>) {
+        /**
+         * The declaration will be visible from external modules as usual.
+         */
+        Public(SkieVisibility.Public::class),
+
+        /**
+         * The declaration will be visible from external modules, but it will be marked as `swift-private`.
+         * (Xcode will not include it in autocomplete suggestions.)
+         */
+        PublicButHidden(SkieVisibility.PublicButHidden::class),
+
+        /**
+         * The declaration will be visible from external modules, but it will be:
+         *  - marked as `swift-private` (Xcode will not include it in autocomplete suggestions.),
+         *  - renamed in Swift by adding the `__` prefix (Obj-C name remains the same); constructors are not affected.
+         */
+        PublicButReplaced(SkieVisibility.PublicButReplaced::class),
+
+        /**
+         * The declaration will be visible only for declarations within the Kotlin module (including custom Swift code bundled by SKIE).
+         */
+        Internal(SkieVisibility.Internal::class),
+
+        /**
+         * The declaration will be visible only for declarations within the Kotlin module (including custom Swift code bundled by SKIE).
+         * Additionally, the declaration will be renamed in Swift by adding the `__` prefix (Obj-C name remains the same); constructors are not affected.
+         */
+        InternalAndReplaced(SkieVisibility.InternalAndReplaced::class),
+
+        /**
+         * The declaration will either be Public or Internal.
+         * Which one is chosen depends on whether the declaration is automatically wrapped by SKIE or not.
+         *
+         * For example, a top-level function originally exposed as `FileKt.functionName` will be internal, if SKIE generated the global function wrapper for it.
+         */
+        InternalIfWrapped(SkieVisibility.InternalIfWrapped::class),
+
+        /**
+         * The declaration will not be visible.
+         *
+         * Note that this doesn't change whether the declaration is exported by the Kotlin compiler, therefore the compilation overhead from the exported declaration remains unchanged.
+         */
+        Private(SkieVisibility.Private::class),
+    }
+
+    override val defaultValue: Level = Level.Public
+
+    override fun valueOf(value: String): Level = Level.valueOf(value)
+
+    override fun findAnnotationValue(configurationTarget: ConfigurationTarget): Level? =
+        Level.values().firstOrNull { configurationTarget.hasAnnotation(it.associatedAnnotation) }
+}

SKIE/kotlin-compiler/core/src/commonMain/kotlin/co/touchlab/skie/configuration/SkieConfiguration.kt

@@ -58,7 +58,7 @@ abstract class SkieConfiguration(
         if (isKeySupported(configurationKey)) {
             return configurationKey.defaultValue
         } else {
-            error("Configuration key $configurationKey is not supported.")
+            error("Configuration key $configurationKey was not registered in ConfigurationProvider.")
         }
     }
 

SKIE/kotlin-compiler/core/src/commonMain/kotlin/co/touchlab/skie/configuration/provider/ConfigurationProvider.kt

@@ -18,6 +18,7 @@ import co.touchlab.skie.configuration.RootConfiguration
 import co.touchlab.skie.configuration.SealedInterop
 import co.touchlab.skie.configuration.SimpleFunctionConfiguration
 import co.touchlab.skie.configuration.SkieConfiguration
+import co.touchlab.skie.configuration.SkieVisibility
 import co.touchlab.skie.configuration.SuppressSkieWarning
 import co.touchlab.skie.configuration.SuspendInterop
 import co.touchlab.skie.configuration.ValueParameterConfiguration
@@ -51,6 +52,7 @@ class ConfigurationProvider(
         SealedInterop.ElseName,
         SealedInterop.Case.Visible,
         SealedInterop.Case.Name,
+        SkieVisibility,
         SuppressSkieWarning.NameCollision,
         SuspendInterop.Enabled,
     )

SKIE/kotlin-compiler/core/src/commonMain/kotlin/co/touchlab/skie/configuration/provider/IdentifiedConfigurationTarget.kt

@@ -20,7 +20,7 @@ interface IdentifiedConfigurationTarget : ConfigurationTarget {
 
         override val scopeType: KClass<out ConfigurationScope> = ConfigurationScope.Root::class
 
-        override fun <T : Annotation> hasAnnotation(kClass: KClass<T>): Boolean = false
+        override fun hasAnnotation(kClass: KClass<out Annotation>): Boolean = false
 
         override fun <T : Annotation> findAnnotation(kClass: KClass<T>): T? = null
     }

SKIE/kotlin-compiler/core/src/commonMain/kotlin/co/touchlab/skie/phases/features/sealed/SealedEnumGeneratorDelegate.kt

@@ -22,13 +22,15 @@ import co.touchlab.skie.oir.type.TypeDefOirType
 import co.touchlab.skie.oir.type.TypeParameterUsageOirType
 import co.touchlab.skie.oir.type.VoidOirType
 import co.touchlab.skie.phases.SirPhase
+import co.touchlab.skie.phases.util.MustBeExecutedAfterBridgingConfiguration
 import co.touchlab.skie.sir.element.SirClass
 import co.touchlab.skie.sir.element.SirEnumCase
 import co.touchlab.skie.sir.element.SirEnumCaseAssociatedValue
 import co.touchlab.skie.sir.element.SirModule
 import co.touchlab.skie.sir.element.SirVisibility
 import co.touchlab.skie.sir.element.copyTypeParametersFrom
 
+@MustBeExecutedAfterBridgingConfiguration
 class SealedEnumGeneratorDelegate(
     override val context: SirPhase.Context,
 ) : SealedGeneratorExtensionContainer {

SKIE/kotlin-compiler/core/src/commonMain/kotlin/co/touchlab/skie/phases/features/sealed/SealedFunctionGeneratorDelegate.kt

@@ -3,6 +3,7 @@ package co.touchlab.skie.phases.features.sealed
 import co.touchlab.skie.configuration.SealedInterop
 import co.touchlab.skie.kir.element.KirClass
 import co.touchlab.skie.phases.SirPhase
+import co.touchlab.skie.phases.util.MustBeExecutedAfterBridgingConfiguration
 import co.touchlab.skie.sir.element.SirClass
 import co.touchlab.skie.sir.element.SirSimpleFunction
 import co.touchlab.skie.sir.element.SirTypeParameter
@@ -17,6 +18,7 @@ import co.touchlab.skie.util.swift.escapeSwiftIdentifier
 import io.outfoxx.swiftpoet.CodeBlock
 import io.outfoxx.swiftpoet.TypeName
 
+@MustBeExecutedAfterBridgingConfiguration
 class SealedFunctionGeneratorDelegate(
     override val context: SirPhase.Context,
 ) : SealedGeneratorExtensionContainer {

SKIE/kotlin-compiler/core/src/commonMain/kotlin/co/touchlab/skie/phases/features/sealed/SealedGeneratorExtensionContainer.kt

@@ -3,14 +3,17 @@ package co.touchlab.skie.phases.features.sealed
 import co.touchlab.skie.configuration.SealedInterop
 import co.touchlab.skie.kir.element.KirClass
 import co.touchlab.skie.phases.SirPhase
+import co.touchlab.skie.phases.util.MustBeExecutedAfterBridgingConfiguration
 import co.touchlab.skie.sir.element.SirClass
+import co.touchlab.skie.sir.element.isAccessibleFromOtherModules
 import co.touchlab.skie.sir.element.superClassType
 import co.touchlab.skie.sir.element.toTypeParameterUsage
 import co.touchlab.skie.sir.type.SirDeclaredSirType
 import co.touchlab.skie.sir.type.SirType
 import co.touchlab.skie.sir.type.TypeParameterUsageSirType
 import co.touchlab.skie.util.swift.toValidSwiftIdentifier
 
+@MustBeExecutedAfterBridgingConfiguration
 interface SealedGeneratorExtensionContainer {
 
     val context: SirPhase.Context
@@ -48,7 +51,7 @@ interface SealedGeneratorExtensionContainer {
             this.visibleSealedSubclasses.isEmpty()
 
     val KirClass.visibleSealedSubclasses: List<KirClass>
-        get() = this.sealedSubclasses.filter { it.configuration[SealedInterop.Case.Visible] }
+        get() = this.sealedSubclasses.filter { it.configuration[SealedInterop.Case.Visible] && it.primarySirClass.visibility.isAccessibleFromOtherModules }
 
     fun SirClass.getSealedSubclassType(
         enum: SirClass,

SKIE/kotlin-compiler/core/src/commonMain/kotlin/co/touchlab/skie/phases/features/suspend/SwiftSuspendFunctionGenerator.kt

@@ -10,6 +10,8 @@ import co.touchlab.skie.sir.element.SirSimpleFunction
 import co.touchlab.skie.sir.element.SirVisibility
 import co.touchlab.skie.sir.element.applyToEntireOverrideHierarchy
 import co.touchlab.skie.sir.element.copyValueParametersFrom
+import co.touchlab.skie.sir.element.isAccessible
+import co.touchlab.skie.sir.element.isAccessibleFromOtherModules
 import co.touchlab.skie.sir.element.shallowCopy
 import co.touchlab.skie.sir.type.NullableSirType
 import co.touchlab.skie.sir.type.OirDeclaredSirType
@@ -35,6 +37,10 @@ class SwiftSuspendFunctionGenerator {
             kotlinBridgingKirFunction = kotlinBridgingKirFunction,
         )
 
+        if (!bridgeModel.originalFunction.visibility.isAccessible) {
+            return
+        }
+
         val extension = sirProvider.getExtension(
             classDeclaration = bridgeModel.extensionTypeDeclarationForBridgingFunction,
             parent = namespaceProvider.getNamespaceFile(bridgeModel.suspendFunctionOwner),

SKIE/kotlin-compiler/core/src/commonMain/kotlin/co/touchlab/skie/phases/sir/member/CreateSirMembersPhase.kt

@@ -1,5 +1,6 @@
 package co.touchlab.skie.phases.sir.member
 
+import co.touchlab.skie.configuration.SkieVisibility
 import co.touchlab.skie.kir.element.KirCallableDeclaration
 import co.touchlab.skie.kir.element.KirClass
 import co.touchlab.skie.kir.element.KirConstructor
@@ -24,12 +25,14 @@ import co.touchlab.skie.sir.element.SirValueParameter
 import co.touchlab.skie.sir.element.SirVisibility
 import co.touchlab.skie.util.collisionFreeIdentifier
 import co.touchlab.skie.util.swift.toValidSwiftIdentifier
+import co.touchlab.skie.util.toSirVisibility
 
 class CreateSirMembersPhase(
     val context: SirPhase.Context,
 ) : SirPhase {
 
     private val kirProvider = context.kirProvider
+    private val sirProvider = context.sirProvider
     private val sirTypeTranslator = context.sirTypeTranslator
 
     context(SirPhase.Context)
@@ -160,10 +163,14 @@ class CreateSirMembersPhase(
         }
 
     private val KirCallableDeclaration<*>.visibility: SirVisibility
-        get() = if (this.isRefinedInSwift) {
-            SirVisibility.PublicButHidden
-        } else {
-            SirVisibility.Public
+        get() {
+            val configuredVisibility = this.configuration[SkieVisibility].toSirVisibility()
+
+            return if (configuredVisibility == SirVisibility.Public && this.isRefinedInSwift) {
+                SirVisibility.PublicButHidden
+            } else {
+                configuredVisibility
+            }
         }
 
     private val KirCallableDeclaration<*>.isReplaced: Boolean

SKIE/kotlin-compiler/core/src/commonMain/kotlin/co/touchlab/skie/phases/sir/type/CreateKotlinSirTypesPhase.kt

@@ -1,5 +1,6 @@
 package co.touchlab.skie.phases.sir.type
 
+import co.touchlab.skie.configuration.SkieVisibility
 import co.touchlab.skie.kir.element.KirClass
 import co.touchlab.skie.kir.element.KirModule
 import co.touchlab.skie.oir.element.OirClass
@@ -8,7 +9,9 @@ import co.touchlab.skie.sir.SirFqName
 import co.touchlab.skie.sir.element.SirClass
 import co.touchlab.skie.sir.element.SirDeclarationParent
 import co.touchlab.skie.sir.element.SirTypeParameter
+import co.touchlab.skie.sir.element.SirVisibility
 import co.touchlab.skie.sir.element.toSirKind
+import co.touchlab.skie.util.toSirVisibility
 
 // Must be class because it has state
 class CreateKotlinSirTypesPhase : SirPhase {
@@ -35,6 +38,7 @@ class CreateKotlinSirTypesPhase : SirPhase {
             parent = kirClass.sirParent,
             kind = kirClass.oirClass.kind.toSirKind(),
             origin = SirClass.Origin.Kir(kirClass),
+            visibility = kirClass.configuration[SkieVisibility].toSirVisibility(),
         )
 
         createTypeParameters(kirClass.oirClass, sirClass)

SKIE/kotlin-compiler/core/src/commonMain/kotlin/co/touchlab/skie/util/SkieVisibilityToSirVisibility.kt

@@ -0,0 +1,15 @@
+package co.touchlab.skie.util
+
+import co.touchlab.skie.configuration.SkieVisibility
+import co.touchlab.skie.sir.element.SirVisibility
+
+fun SkieVisibility.Level.toSirVisibility(isWrapped: Boolean = false): SirVisibility =
+    when (this) {
+        SkieVisibility.Level.Public -> SirVisibility.Public
+        SkieVisibility.Level.PublicButHidden -> SirVisibility.PublicButHidden
+        SkieVisibility.Level.PublicButReplaced -> SirVisibility.PublicButHidden
+        SkieVisibility.Level.Internal -> SirVisibility.Internal
+        SkieVisibility.Level.InternalAndReplaced -> SirVisibility.Internal
+        SkieVisibility.Level.InternalIfWrapped -> if (isWrapped) SirVisibility.Internal else SirVisibility.Public
+        SkieVisibility.Level.Private -> SirVisibility.Private
+    }