DescriptorUtils: add getPackagesFqNames

core/descriptors/src/org/jetbrains/kotlin/resolve/DescriptorUtils.java

@@ -28,6 +28,7 @@ import org.jetbrains.kotlin.name.FqName;
 import org.jetbrains.kotlin.name.FqNameUnsafe;
 import org.jetbrains.kotlin.name.Name;
 import org.jetbrains.kotlin.name.SpecialNames;
+import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter;
 import org.jetbrains.kotlin.resolve.scopes.FilteringScope;
 import org.jetbrains.kotlin.resolve.scopes.JetScope;
 import org.jetbrains.kotlin.types.ErrorUtils;
@@ -500,4 +501,28 @@ public class DescriptorUtils {
     public static boolean canHaveSecondaryConstructors(@NotNull ClassDescriptor classDescriptor) {
         return !isSingletonOrAnonymousObject(classDescriptor) && !isTrait(classDescriptor);
     }
+
+    public static Set<FqName> getPackagesFqNames(ModuleDescriptor module) {
+        return getSubPackagesFqNames(module.getPackage(FqName.ROOT));
+    }
+
+    public static Set<FqName> getSubPackagesFqNames(PackageViewDescriptor packageView) {
+        Set<FqName> result = new HashSet<FqName>();
+        getSubPackagesFqNames(packageView, result);
+
+        return result;
+    }
+
+    private static void getSubPackagesFqNames(PackageViewDescriptor packageView, Set<FqName> result) {
+        FqName fqName = packageView.getFqName();
+        if (!fqName.isRoot()) {
+            result.add(fqName);
+        }
+
+        for (DeclarationDescriptor descriptor : packageView.getMemberScope().getDescriptors(DescriptorKindFilter.PACKAGES, JetScope.ALL_NAME_FILTER)) {
+            if (descriptor instanceof PackageViewDescriptor) {
+                getSubPackagesFqNames((PackageViewDescriptor) descriptor, result);
+            }
+        }
+    }
 }