~ EXAMPLE How to create a class descriptor and a instance function inside it

Author: yanex

plugins/android-extensions/android-extensions-compiler/src/org/jetbrains/kotlin/android/synthetic/descriptors/PredefinedPackageFragmentDescriptor.kt

@@ -16,10 +16,7 @@
 
 package org.jetbrains.kotlin.android.synthetic.descriptors
 
-import org.jetbrains.kotlin.descriptors.ModuleDescriptor
-import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
-import org.jetbrains.kotlin.descriptors.PropertyDescriptor
-import org.jetbrains.kotlin.descriptors.SimpleFunctionDescriptor
+import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.impl.PackageFragmentDescriptorImpl
 import org.jetbrains.kotlin.incremental.components.LookupLocation
 import org.jetbrains.kotlin.name.FqName
@@ -34,12 +31,17 @@ class PredefinedPackageFragmentDescriptor(
         module: ModuleDescriptor,
         storageManager: StorageManager,
         val subpackages: List<PackageFragmentDescriptor> = emptyList(),
-        private val functions: (PredefinedPackageFragmentDescriptor) -> Collection<SimpleFunctionDescriptor> = { emptyList() }
+        private val functions: (PredefinedPackageFragmentDescriptor) -> Collection<SimpleFunctionDescriptor> = { emptyList() },
+        private val classifiers: (PredefinedPackageFragmentDescriptor) -> Collection<ClassifierDescriptor> = { emptyList() }
 ) : PackageFragmentDescriptorImpl(module, FqName(fqName)) {
     private val calculatedFunctions = storageManager.createLazyValue {
         functions(this)
     }
 
+    private val calculatedClassifiers = storageManager.createLazyValue {
+        classifiers(this)
+    }
+
     private val scope = PredefinedScope()
 
     override fun getMemberScope() = scope
@@ -49,11 +51,16 @@ class PredefinedPackageFragmentDescriptor(
 
         override fun getContributedFunctions(name: Name, location: LookupLocation) = calculatedFunctions().filter { it.name == name }
 
+        override fun getContributedClassifier(name: Name, location: LookupLocation): ClassifierDescriptor? {
+            return calculatedClassifiers().firstOrNull { name == it.name }
+        }
+
         override fun getContributedDescriptors(
                 kindFilter: DescriptorKindFilter,
                 nameFilter: (Name) -> Boolean
-        ): List<SimpleFunctionDescriptor> {
-            return calculatedFunctions().filter { nameFilter(it.name) && kindFilter.accepts(it) }
+        ): List<DeclarationDescriptorNonRoot> {
+            return calculatedFunctions().filter { nameFilter(it.name) && kindFilter.accepts(it) } +
+                   calculatedClassifiers().filter { nameFilter(it.name) && kindFilter.accepts(it) }
         }
 
         override fun printScopeStructure(p: Printer) {

plugins/android-extensions/android-extensions-compiler/src/org/jetbrains/kotlin/android/synthetic/res/AndroidPackageFragmentProviderExtension.kt

@@ -82,14 +82,16 @@ abstract class AndroidPackageFragmentProviderExtension : PackageFragmentProvider
 
         // Package with clearFindViewByIdCache()
         AndroidConst.SYNTHETIC_SUBPACKAGES.last().let { s ->
-            val packageDescriptor = PredefinedPackageFragmentDescriptor(s, module, storageManager, packagesToLookupInCompletion) { descriptor ->
+            val packageDescriptor = PredefinedPackageFragmentDescriptor(s, module, storageManager, packagesToLookupInCompletion, { descriptor ->
                 val widgetReceivers = lazyContext().getWidgetReceivers(forView = false, isExperimental = isExperimental) +
                                       lazyContext().getWidgetReceivers(forView = true, isExperimental = isExperimental)
 
                 widgetReceivers
                         .filter { it.mayHaveCache }
                         .map { genClearCacheFunction(descriptor, it.type) }
-            }
+            }, { descriptor ->
+                listOf(genSimpleClass(descriptor))
+            })
             packagesToLookupInCompletion += packageDescriptor
             allPackageDescriptors += packageDescriptor
         }

plugins/android-extensions/android-extensions-compiler/src/org/jetbrains/kotlin/android/synthetic/res/syntheticDescriptorGeneration.kt

@@ -22,20 +22,54 @@ import org.jetbrains.kotlin.android.synthetic.descriptors.AndroidSyntheticPackag
 import org.jetbrains.kotlin.android.synthetic.descriptors.SyntheticElementResolveContext
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.annotations.Annotations
-import org.jetbrains.kotlin.descriptors.impl.PropertyDescriptorImpl
-import org.jetbrains.kotlin.descriptors.impl.PropertyGetterDescriptorImpl
-import org.jetbrains.kotlin.descriptors.impl.SimpleFunctionDescriptorImpl
+import org.jetbrains.kotlin.descriptors.impl.*
+import org.jetbrains.kotlin.incremental.components.LookupLocation
 import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.resolve.DescriptorFactory
+import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.resolve.descriptorUtil.builtIns
 import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameUnsafe
+import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
+import org.jetbrains.kotlin.resolve.scopes.MemberScopeImpl
 import org.jetbrains.kotlin.resolve.source.PsiSourceElement
-import org.jetbrains.kotlin.types.KotlinType
-import org.jetbrains.kotlin.types.KotlinTypeFactory
-import org.jetbrains.kotlin.types.SimpleType
-import org.jetbrains.kotlin.types.StarProjectionImpl
+import org.jetbrains.kotlin.types.*
+import org.jetbrains.kotlin.utils.Printer
 
 private class XmlSourceElement(override val psi: PsiElement) : PsiSourceElement
 
+internal fun genSimpleClass(packageFragmentDescriptor: PackageFragmentDescriptor): ClassDescriptor {
+    val classDescriptor = ClassDescriptorImpl(packageFragmentDescriptor, Name.identifier("Test"), Modality.FINAL, ClassKind.CLASS,
+            listOf(packageFragmentDescriptor.builtIns.anyType), SourceElement.NO_SOURCE, false)
+
+    val primaryConstructor = ClassConstructorDescriptorImpl.create(classDescriptor, Annotations.EMPTY, true, SourceElement.NO_SOURCE).apply {
+        initialize(emptyList(), Visibilities.PUBLIC)
+    }
+
+    val simpleFunction = SimpleFunctionDescriptorImpl.create(classDescriptor, Annotations.EMPTY, Name.identifier("foo"),
+            CallableMemberDescriptor.Kind.DECLARATION, SourceElement.NO_SOURCE)
+
+    simpleFunction.initialize(null, classDescriptor.thisAsReceiverParameter, emptyList(), emptyList(),
+                              packageFragmentDescriptor.builtIns.stringType, Modality.FINAL, Visibilities.PUBLIC)
+
+    val scope = object : MemberScopeImpl() {
+        override fun getContributedFunctions(name: Name, location: LookupLocation) = listOf(simpleFunction)
+        override fun printScopeStructure(p: Printer) { p.println(this::class.java.simpleName) }
+        override fun getContributedDescriptors(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean): Collection<DeclarationDescriptor> {
+            return when {
+                kindFilter.accepts(simpleFunction) && nameFilter(simpleFunction.name) -> listOf(simpleFunction)
+                kindFilter.accepts(primaryConstructor) && nameFilter(primaryConstructor.name) -> listOf(primaryConstructor)
+                else -> emptyList()
+            }
+        }
+    }
+
+    classDescriptor.initialize(scope, setOf(primaryConstructor), primaryConstructor)
+
+    primaryConstructor.returnType = KotlinTypeFactory.simpleNotNullType(Annotations.EMPTY, classDescriptor, emptyList())
+
+    return classDescriptor
+}
+
 internal fun genClearCacheFunction(packageFragmentDescriptor: PackageFragmentDescriptor, receiverType: KotlinType): SimpleFunctionDescriptor {
     val function = object : AndroidSyntheticFunction, SimpleFunctionDescriptorImpl(
             packageFragmentDescriptor,