Add static members into the list one by one

idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/StaticMembersCompletion.kt

@@ -26,6 +26,7 @@ import org.jetbrains.kotlin.idea.core.KotlinIndicesHelper
 import org.jetbrains.kotlin.idea.core.targetDescriptors
 import org.jetbrains.kotlin.idea.resolve.ResolutionFacade
 import org.jetbrains.kotlin.lexer.KtTokens
+import org.jetbrains.kotlin.psi.KtCallableDeclaration
 import org.jetbrains.kotlin.psi.KtClass
 import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.psi.KtObjectDeclaration
@@ -87,23 +88,26 @@ class StaticMembersCompletion(
     //TODO: better presentation for lookup elements from imports too
     //TODO: from the same file
 
-    fun membersFromIndices(indicesHelper: KotlinIndicesHelper): Collection<DeclarationDescriptor> {
+    fun processMembersFromIndices(indicesHelper: KotlinIndicesHelper, processor: (DeclarationDescriptor) -> Unit) {
         val descriptorKindFilter = DescriptorKindFilter.CALLABLES exclude DescriptorKindExclude.Extensions
         val nameFilter: (String) -> Boolean = { prefixMatcher.prefixMatches(it) }
 
-        val result = ArrayList<DeclarationDescriptor>()
+        val filter = { declaration: KtCallableDeclaration, objectDeclaration: KtObjectDeclaration ->
+            !declaration.hasModifier(KtTokens.OVERRIDE_KEYWORD) && objectDeclaration.isTopLevelOrCompanion()
+        }
+        indicesHelper.processObjectMembers(descriptorKindFilter, nameFilter, filter) {
+            if (it !in alreadyAdded) { //TODO: substitution
+                processor(it)
+            }
+        }
 
         if (isJvmModule) {
-            indicesHelper.getJavaStaticMembers(descriptorKindFilter, nameFilter).filterTo(result) { it !in alreadyAdded }  //TODO: substitution
+            indicesHelper.processJavaStaticMembers(descriptorKindFilter, nameFilter){
+                if (it !in alreadyAdded) { //TODO: substitution
+                    processor(it)
+                }
+            }
         }
-
-        indicesHelper.getObjectMembers(descriptorKindFilter, nameFilter) filter@ { declaration, objectDeclaration ->
-            !declaration.hasModifier(KtTokens.OVERRIDE_KEYWORD) && objectDeclaration.isTopLevelOrCompanion()
-        }.filterTo(result) {
-            it !in alreadyAdded //TODO: substitution
-        }
-
-        return result
     }
 
     private fun KtObjectDeclaration.isTopLevelOrCompanion(): Boolean {
@@ -125,8 +129,9 @@ class StaticMembersCompletion(
 
     fun completeFromIndices(indicesHelper: KotlinIndicesHelper, collector: LookupElementsCollector) {
         val factory = decoratedLookupElementFactory(ItemPriority.STATIC_MEMBER)
-        membersFromIndices(indicesHelper)
-                .flatMap { factory.createStandardLookupElementsForDescriptor(it, useReceiverTypes = true) }
-                .forEach { collector.addElement(it) }
+        processMembersFromIndices(indicesHelper) {
+            factory.createStandardLookupElementsForDescriptor(it, useReceiverTypes = true).forEach { collector.addElement(it) }
+            collector.flushToResultSet()
+        }
     }
 }

idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/smart/SmartCompletionSession.kt

@@ -137,9 +137,12 @@ class SmartCompletionSession(configuration: CompletionSessionConfiguration, para
 
                 if (staticMembersCompletion != null && configuration.completeStaticMembers) {
                     val decoratedFactory = staticMembersCompletion.decoratedLookupElementFactory(ItemPriority.STATIC_MEMBER)
-                    staticMembersCompletion.membersFromIndices(indicesHelper(false))
-                            .flatMap { filter(it, decoratedFactory) }
-                            .forEach { collector.addElement(it) }
+                    staticMembersCompletion.processMembersFromIndices(indicesHelper(false)) {
+                        filter(it, decoratedFactory).forEach {
+                            collector.addElement(it)
+                            flushToResultSet()
+                        }
+                    }
                 }
             }
         }

idea/idea-core/src/org/jetbrains/kotlin/idea/core/KotlinIndicesHelper.kt

@@ -197,14 +197,13 @@ public class KotlinIndicesHelper(
                 .filter(descriptorFilter)
     }
 
-    public fun getObjectMembers(
+    public fun processObjectMembers(
             descriptorKindFilter: DescriptorKindFilter,
             nameFilter: (String) -> Boolean,
-            filter: (KtCallableDeclaration, KtObjectDeclaration) -> Boolean
-    ): Collection<CallableDescriptor> {
-        val result = LinkedHashSet<CallableDescriptor>()
-
-        fun addFromIndex(index: StringStubIndexExtension<out KtCallableDeclaration>) {
+            filter: (KtCallableDeclaration, KtObjectDeclaration) -> Boolean,
+            processor: (DeclarationDescriptor) -> Unit
+    ) {
+        fun processIndex(index: StringStubIndexExtension<out KtCallableDeclaration>) {
             for (name in index.getAllKeys(project)) {
                 ProgressManager.checkCanceled()
                 if (!nameFilter(name)) continue
@@ -214,24 +213,28 @@ public class KotlinIndicesHelper(
                     if (objectDeclaration.isObjectLiteral()) continue
                     if (!visibilityFilterMayIncludeAccessible && declaration.hasModifier(KtTokens.PRIVATE_KEYWORD)) continue
                     if (!filter(declaration, objectDeclaration)) continue
-                    declaration.resolveToDescriptorsWithHack().filterTo(result) { descriptorKindFilter.accepts(it) && descriptorFilter(it) }
+                    for (descriptor in declaration.resolveToDescriptorsWithHack()) {
+                        if (descriptorKindFilter.accepts(descriptor) && descriptorFilter(descriptor)) {
+                            processor(descriptor)
+                        }
+                    }
                 }
             }
         }
 
         if (descriptorKindFilter.kindMask.and(DescriptorKindFilter.FUNCTIONS_MASK) != 0) {
-            addFromIndex(KotlinFunctionShortNameIndex.getInstance())
+            processIndex(KotlinFunctionShortNameIndex.getInstance())
         }
         if (descriptorKindFilter.kindMask.and(DescriptorKindFilter.VARIABLES_MASK) != 0) {
-            addFromIndex(KotlinPropertyShortNameIndex.getInstance())
+            processIndex(KotlinPropertyShortNameIndex.getInstance())
         }
-
-        return result
     }
 
-    public fun getJavaStaticMembers(descriptorKindFilter: DescriptorKindFilter, nameFilter: (String) -> Boolean): Collection<CallableDescriptor> {
-        val result = LinkedHashSet<CallableDescriptor>()
-
+    public fun processJavaStaticMembers(
+            descriptorKindFilter: DescriptorKindFilter,
+            nameFilter: (String) -> Boolean,
+            processor: (DeclarationDescriptor) -> Unit
+    ) {
         val idFilter = IdFilter.getProjectIdFilter(resolutionFacade.project, false)
         val shortNamesCache = PsiShortNamesCache.getInstance(project)
 
@@ -246,12 +249,13 @@ public class KotlinIndicesHelper(
                 val descriptor = method.getJavaMethodDescriptor(resolutionFacade) ?: continue
                 val container = descriptor.containingDeclaration as? ClassDescriptor ?: continue
                 if (descriptorKindFilter.accepts(descriptor) && descriptorFilter(descriptor)) {
-                    result.add(descriptor)
+                    processor(descriptor)
 
-                    val samAdapter = container.staticScope.getContributedFunctions(descriptor.name, NoLookupLocation.FROM_IDE)
+                    // SAM-adapter
+                    container.staticScope.getContributedFunctions(descriptor.name, NoLookupLocation.FROM_IDE)
                             .filterIsInstance<SamAdapterDescriptor<*>>()
                             .firstOrNull { it.originForSam.original == descriptor.original }
-                    result.addIfNotNull(samAdapter)
+                            ?.let { processor(it) }
                 }
             }
             true
@@ -267,14 +271,12 @@ public class KotlinIndicesHelper(
                 if (!visibilityFilterMayIncludeAccessible && field.hasModifierProperty(PsiModifier.PRIVATE)) continue
                 val descriptor = field.getJavaFieldDescriptor() ?: continue
                 if (descriptorKindFilter.accepts(descriptor) && descriptorFilter(descriptor)) {
-                    result.add(descriptor)
+                    processor(descriptor)
                 }
             }
             true
         }
         shortNamesCache.processAllFieldNames(fieldNamesProcessor, scope, idFilter)
-
-        return result
     }
 
     private fun findTopLevelCallables(fqName: FqName): Collection<CallableDescriptor> {