[kotlinx-metadata] Add extensions for type aliases.

libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/impl/JvmMetadataExtensions.kt

@@ -107,6 +107,8 @@ internal class JvmMetadataExtensions : MetadataExtensions {
         ext.visitEnd()
     }
 
+    override fun readTypeAliasExtensions(v: KmTypeAliasVisitor, proto: ProtoBuf.TypeAlias, c: ReadContext) {}
+
     override fun writeClassExtensions(type: KmExtensionType, proto: ProtoBuf.Class.Builder, c: WriteContext): KmClassExtensionVisitor? {
         if (type != JvmClassExtensionVisitor.TYPE) return null
         return object : JvmClassExtensionVisitor() {
@@ -268,6 +270,12 @@ internal class JvmMetadataExtensions : MetadataExtensions {
         }
     }
 
+    override fun writeTypeAliasExtensions(
+        type: KmExtensionType,
+        proto: ProtoBuf.TypeAlias.Builder,
+        c: WriteContext
+    ): KmTypeAliasExtensionVisitor? = null
+
     override fun createClassExtension(): KmClassExtension = JvmClassExtension()
 
     override fun createPackageExtension(): KmPackageExtension = JvmPackageExtension()
@@ -285,6 +293,8 @@ internal class JvmMetadataExtensions : MetadataExtensions {
 
     override fun createTypeExtension(): KmTypeExtension = JvmTypeExtension()
 
+    override fun createTypeAliasExtension(): KmTypeAliasExtension = JvmTypeAliasExtension()
+
     private fun JvmMemberSignature.toJvmMethodSignature(c: WriteContext): JvmProtoBuf.JvmMethodSignature =
         JvmProtoBuf.JvmMethodSignature.newBuilder().apply {
             name = c[this@toJvmMethodSignature.name]

libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/impl/jvmExtensionNodes.kt

@@ -176,3 +176,10 @@ internal class JvmTypeExtension : JvmTypeExtensionVisitor(), KmTypeExtension {
         visitor.visitEnd()
     }
 }
+
+internal class JvmTypeAliasExtension : JvmTypeAliasExtensionVisitor(), KmTypeAliasExtension {
+    override fun accept(visitor: KmTypeExtensionVisitor) {
+        require(visitor is JvmTypeAliasExtensionVisitor)
+        visitor.visitEnd()
+    }
+}

libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/jvmExtensionVisitors.kt

@@ -348,3 +348,30 @@ open class JvmTypeExtensionVisitor @JvmOverloads constructor(
         const val PLATFORM_TYPE_ID = JvmProtoBufUtil.PLATFORM_TYPE_ID
     }
 }
+
+/**
+ * A visitor to visit JVM extensions for a type alias.
+ */
+open class JvmTypeAliasExtensionVisitor @JvmOverloads constructor(
+    private val delegate: JvmTypeAliasExtensionVisitor? = null
+) : KmTypeAliasExtensionVisitor {
+    final override val type: KmExtensionType
+        get() = TYPE
+
+    /**
+     * Visits the end of JVM extensions for the type alias.
+     */
+    open fun visitEnd() {
+        delegate?.visitEnd()
+    }
+
+    companion object {
+        /**
+         * The type of this extension visitor.
+         *
+         * @see KmExtensionType
+         */
+        @JvmField
+        val TYPE: KmExtensionType = KmExtensionType(JvmTypeAliasExtensionVisitor::class)
+    }
+}

libraries/kotlinx-metadata/klib/src/kotlinx/metadata/klib/impl/klibExtensionNodes.kt

@@ -33,6 +33,9 @@ internal val KmPackage.klibExtensions: KlibPackageExtension
 internal val KmModuleFragment.klibExtensions: KlibModuleFragmentExtension
     get() = visitExtensions(KlibModuleFragmentExtensionVisitor.TYPE) as KlibModuleFragmentExtension
 
+internal val KmTypeAlias.klibExtensions: KlibTypeAliasExtension
+    get() = visitExtensions(KlibTypeAliasExtensionVisitor.TYPE) as KlibTypeAliasExtension
+
 internal class KlibFunctionExtension : KlibFunctionExtensionVisitor(), KmFunctionExtension {
 
     val annotations: MutableList<KmAnnotation> = mutableListOf()
@@ -222,3 +225,16 @@ internal class KlibModuleFragmentExtension : KlibModuleFragmentExtensionVisitor(
         className.forEach(visitor::visitClassName)
     }
 }
+
+internal class KlibTypeAliasExtension : KlibTypeAliasExtensionVisitor(), KmTypeAliasExtension {
+    var uniqId: UniqId? = null
+
+    override fun visitUniqId(uniqId: UniqId) {
+        this.uniqId = uniqId
+    }
+
+    override fun accept(visitor: KmTypeExtensionVisitor) {
+        require(visitor is KlibTypeAliasExtensionVisitor)
+        uniqId?.let(visitor::visitUniqId)
+    }
+}

libraries/kotlinx-metadata/klib/src/kotlinx/metadata/klib/impl/klibMetadataExtensions.kt

@@ -126,6 +126,14 @@ internal class KlibMetadataExtensions : MetadataExtensions {
         }
     }
 
+    override fun readTypeAliasExtensions(v: KmTypeAliasVisitor, proto: ProtoBuf.TypeAlias, c: ReadContext) {
+        val extension = v.visitExtensions(KlibTypeAliasExtensionVisitor.TYPE) as? KlibTypeAliasExtensionVisitor ?: return
+
+        proto.getExtension(KlibMetadataProtoBuf.typeAliasUniqId).let { descriptorUniqId ->
+            extension.visitUniqId(descriptorUniqId.readUniqId())
+        }
+    }
+
     override fun writeClassExtensions(type: KmExtensionType, proto: ProtoBuf.Class.Builder, c: WriteContext): KmClassExtensionVisitor? {
         if (type != KlibClassExtensionVisitor.TYPE) return null
         return object : KlibClassExtensionVisitor() {
@@ -324,6 +332,22 @@ internal class KlibMetadataExtensions : MetadataExtensions {
         }
     }
 
+    override fun writeTypeAliasExtensions(
+        type: KmExtensionType,
+        proto: ProtoBuf.TypeAlias.Builder,
+        c: WriteContext
+    ): KmTypeAliasExtensionVisitor? {
+        if (type != KlibTypeAliasExtensionVisitor.TYPE) return null
+        return object : KlibTypeAliasExtensionVisitor() {
+            override fun visitUniqId(uniqId: UniqId) {
+                proto.setExtension(
+                    KlibMetadataProtoBuf.typeAliasUniqId,
+                    uniqId.writeUniqId().build()
+                )
+            }
+        }
+    }
+
     override fun createClassExtension(): KmClassExtension =
         KlibClassExtension()
 
@@ -347,4 +371,7 @@ internal class KlibMetadataExtensions : MetadataExtensions {
 
     override fun createTypeExtension(): KmTypeExtension =
         KlibTypeExtension()
+
+    override fun createTypeAliasExtension(): KmTypeAliasExtension =
+        KlibTypeAliasExtension()
 }

libraries/kotlinx-metadata/klib/src/kotlinx/metadata/klib/klibExtensions.kt

@@ -103,3 +103,9 @@ var KmTypeParameter.uniqId: UniqId?
     set(value) {
         klibExtensions.uniqId = value
     }
+
+var KmTypeAlias.uniqId: UniqId?
+    get() = klibExtensions.uniqId
+    set(value) {
+        klibExtensions.uniqId = value
+    }

libraries/kotlinx-metadata/klib/src/kotlinx/metadata/klib/klibMetadataExtensionVisitors.kt

@@ -128,3 +128,15 @@ abstract class KlibModuleFragmentExtensionVisitor : KmModuleFragmentExtensionVis
         val TYPE = KmExtensionType(KlibModuleFragmentExtensionVisitor::class)
     }
 }
+
+abstract class KlibTypeAliasExtensionVisitor : KmTypeAliasExtensionVisitor {
+
+    abstract fun visitUniqId(uniqId: UniqId)
+
+    override val type: KmExtensionType
+        get() = TYPE
+
+    companion object {
+        val TYPE = KmExtensionType(KlibTypeAliasExtensionVisitor::class)
+    }
+}

libraries/kotlinx-metadata/src/kotlinx/metadata/extensions.kt

@@ -93,3 +93,8 @@ interface KmTypeParameterExtensionVisitor : KmExtensionVisitor
  * A visitor to visit platform-specific extensions for a type.
  */
 interface KmTypeExtensionVisitor : KmExtensionVisitor
+
+/**
+ * A visitor to visit platform-specific extensions for a type alias.
+ */
+interface KmTypeAliasExtensionVisitor : KmExtensionVisitor

libraries/kotlinx-metadata/src/kotlinx/metadata/impl/extensions/MetadataExtensions.kt

@@ -28,6 +28,8 @@ interface MetadataExtensions {
 
     fun readTypeExtensions(v: KmTypeVisitor, proto: ProtoBuf.Type, c: ReadContext)
 
+    fun readTypeAliasExtensions(v: KmTypeAliasVisitor, proto: ProtoBuf.TypeAlias, c: ReadContext)
+
     fun writeClassExtensions(type: KmExtensionType, proto: ProtoBuf.Class.Builder, c: WriteContext): KmClassExtensionVisitor?
 
     fun writePackageExtensions(type: KmExtensionType, proto: ProtoBuf.Package.Builder, c: WriteContext): KmPackageExtensionVisitor?
@@ -50,6 +52,8 @@ interface MetadataExtensions {
 
     fun writeTypeExtensions(type: KmExtensionType, proto: ProtoBuf.Type.Builder, c: WriteContext): KmTypeExtensionVisitor?
 
+    fun writeTypeAliasExtensions(type: KmExtensionType, proto: ProtoBuf.TypeAlias.Builder, c: WriteContext): KmTypeAliasExtensionVisitor?
+
     fun createClassExtension(): KmClassExtension
 
     fun createPackageExtension(): KmPackageExtension
@@ -66,6 +70,8 @@ interface MetadataExtensions {
 
     fun createTypeExtension(): KmTypeExtension
 
+    fun createTypeAliasExtension(): KmTypeAliasExtension
+
     companion object {
         val INSTANCES: List<MetadataExtensions> by lazy {
             ServiceLoader.load(MetadataExtensions::class.java, MetadataExtensions::class.java.classLoader).toList().also {

libraries/kotlinx-metadata/src/kotlinx/metadata/impl/extensions/extensionNodes.kt

@@ -26,3 +26,5 @@ interface KmConstructorExtension : KmConstructorExtensionVisitor, KmExtension<Km
 interface KmTypeParameterExtension : KmTypeParameterExtensionVisitor, KmExtension<KmTypeParameterExtensionVisitor>
 
 interface KmTypeExtension : KmTypeExtensionVisitor, KmExtension<KmTypeExtensionVisitor>
+
+interface KmTypeAliasExtension : KmTypeAliasExtensionVisitor, KmExtension<KmTypeExtensionVisitor>

libraries/kotlinx-metadata/src/kotlinx/metadata/nodes.kt

@@ -516,6 +516,9 @@ class KmTypeAlias(
      */
     val versionRequirements: MutableList<KmVersionRequirement> = ArrayList(0)
 
+    private val extensions: List<KmTypeAliasExtension> =
+        MetadataExtensions.INSTANCES.map(MetadataExtensions::createTypeAliasExtension)
+
     override fun visitTypeParameter(flags: Flags, name: String, id: Int, variance: KmVariance): KmTypeParameterVisitor =
         KmTypeParameter(flags, name, id, variance).addTo(typeParameters)
 
@@ -529,6 +532,9 @@ class KmTypeAlias(
         annotations.add(annotation)
     }
 
+    override fun visitExtensions(type: KmExtensionType): KmTypeAliasExtensionVisitor? =
+        extensions.singleOfType(type)
+
     override fun visitVersionRequirement(): KmVersionRequirementVisitor =
         KmVersionRequirement().addTo(versionRequirements)
 

libraries/kotlinx-metadata/src/kotlinx/metadata/visitors.kt

@@ -464,6 +464,14 @@ abstract class KmTypeAliasVisitor @JvmOverloads constructor(private val delegate
     open fun visitVersionRequirement(): KmVersionRequirementVisitor? =
         delegate?.visitVersionRequirement()
 
+    /**
+     * Visits the extensions of the given type on the type alias.
+     *
+     * @param type the type of extension visitor to be returned
+     */
+    open fun visitExtensions(type: KmExtensionType): KmTypeAliasExtensionVisitor? =
+        delegate?.visitExtensions(type)
+
     /**
      * Visits the end of the type alias.
      */