Added optimized PackageFragmentProvider#isEmpty(FqName)

core/descriptors.jvm/src/org/jetbrains/kotlin/load/java/lazy/LazyJavaPackageFragmentProvider.kt

@@ -46,6 +46,10 @@ class LazyJavaPackageFragmentProvider(
     override fun collectPackageFragments(fqName: FqName, packageFragments: MutableCollection<PackageFragmentDescriptor>) =
         packageFragments.addIfNotNull(getPackageFragment(fqName))
 
+    override fun isEmpty(fqName: FqName): Boolean {
+        return c.components.finder.findPackage(fqName) == null
+    }
+
     override fun getSubPackagesOf(fqName: FqName, nameFilter: (Name) -> Boolean) =
         getPackageFragment(fqName)?.getSubPackageFqNames().orEmpty()
 }

core/descriptors/src/org/jetbrains/kotlin/descriptors/PackageFragmentProvider.kt

@@ -34,6 +34,7 @@ interface PackageFragmentProvider {
 
 interface PackageFragmentProviderOptimized : PackageFragmentProvider {
     fun collectPackageFragments(fqName: FqName, packageFragments: MutableCollection<PackageFragmentDescriptor>)
+    fun isEmpty(fqName: FqName): Boolean
 }
 
 fun PackageFragmentProvider.packageFragments(fqName: FqName): List<PackageFragmentDescriptor> {
@@ -42,6 +43,13 @@ fun PackageFragmentProvider.packageFragments(fqName: FqName): List<PackageFragme
     return packageFragments
 }
 
+fun PackageFragmentProvider.isEmpty(fqName: FqName): Boolean {
+    return when (this) {
+        is PackageFragmentProviderOptimized -> isEmpty(fqName)
+        else -> packageFragments(fqName).isEmpty()
+    }
+}
+
 fun PackageFragmentProvider.collectPackageFragmentsOptimizedIfPossible(
     fqName: FqName,
     packageFragments: MutableCollection<PackageFragmentDescriptor>

core/descriptors/src/org/jetbrains/kotlin/descriptors/PackageFragmentProviderImpl.kt

@@ -26,6 +26,9 @@ class PackageFragmentProviderImpl(
         this.packageFragments.filterTo(packageFragments) { it.fqName == fqName }
     }
 
+    override fun isEmpty(fqName: FqName): Boolean =
+        this.packageFragments.none { it.fqName == fqName }
+
     override fun getPackageFragments(fqName: FqName): List<PackageFragmentDescriptor> =
         packageFragments.filter { it.fqName == fqName }
 

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/CompositePackageFragmentProvider.kt

@@ -16,10 +16,7 @@
 
 package org.jetbrains.kotlin.descriptors.impl
 
-import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
-import org.jetbrains.kotlin.descriptors.PackageFragmentProvider
-import org.jetbrains.kotlin.descriptors.PackageFragmentProviderOptimized
-import org.jetbrains.kotlin.descriptors.collectPackageFragmentsOptimizedIfPossible
+import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.name.FqName
 import java.util.*
 import org.jetbrains.kotlin.name.Name
@@ -48,6 +45,9 @@ class CompositePackageFragmentProvider(// can be modified from outside
         }
     }
 
+    override fun isEmpty(fqName: FqName): Boolean =
+        providers.all { it.isEmpty(fqName) }
+
     override fun getSubPackagesOf(fqName: FqName, nameFilter: (Name) -> Boolean): Collection<FqName> {
         val result = HashSet<FqName>()
         for (provider in providers) {

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/LazyPackageViewDescriptorImpl.kt

@@ -16,11 +16,8 @@
 
 package org.jetbrains.kotlin.descriptors.impl
 
-import org.jetbrains.kotlin.descriptors.DeclarationDescriptorVisitor
-import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
-import org.jetbrains.kotlin.descriptors.PackageViewDescriptor
+import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.annotations.Annotations
-import org.jetbrains.kotlin.descriptors.packageFragments
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.resolve.scopes.ChainedMemberScope
 import org.jetbrains.kotlin.resolve.scopes.LazyScopeAdapter
@@ -38,8 +35,14 @@ open class LazyPackageViewDescriptorImpl(
         module.packageFragmentProvider.packageFragments(fqName)
     }
 
+    protected val empty: Boolean by storageManager.createLazyValue {
+        module.packageFragmentProvider.isEmpty(fqName)
+    }
+
+    override fun isEmpty(): Boolean = empty
+
     override val memberScope: MemberScope = LazyScopeAdapter(storageManager) {
-        if (fragments.isEmpty()) {
+        if (isEmpty()) {
             MemberScope.Empty
         } else {
             // Packages from SubpackagesScope are got via getContributedDescriptors(DescriptorKindFilter.PACKAGES, MemberScope.ALL_NAME_FILTER)

core/deserialization/src/org/jetbrains/kotlin/serialization/deserialization/AbstractDeserializedPackageFragmentProvider.kt

@@ -43,6 +43,15 @@ abstract class AbstractDeserializedPackageFragmentProvider(
         packageFragments.addIfNotNull(fragments(fqName))
     }
 
+    override fun isEmpty(fqName: FqName): Boolean {
+        val descriptor = if (fragments.isComputed(fqName)) {
+            fragments.invoke(fqName)
+        } else {
+            findPackage(fqName)
+        }
+        return descriptor == null
+    }
+
     override fun getPackageFragments(fqName: FqName): List<PackageFragmentDescriptor> = listOfNotNull(fragments(fqName))
 
     override fun getSubPackagesOf(fqName: FqName, nameFilter: (Name) -> Boolean): Collection<FqName> = emptySet()