Introduce index for the set of top-level names by package

It should help with actual loading of all the stubs for all declarations
in the package on every access when it's implemented through
`getDeclarations()`

idea/idea-analysis/src/org/jetbrains/kotlin/idea/stubindex/resolve/StubBasedPackageMemberDeclarationProvider.kt

@@ -19,8 +19,10 @@ package org.jetbrains.kotlin.idea.stubindex.resolve
 import com.intellij.openapi.project.Project
 import com.intellij.psi.search.GlobalSearchScope
 import com.intellij.psi.stubs.StringStubIndexExtension
+import com.intellij.util.indexing.FileBasedIndex
 import org.jetbrains.kotlin.idea.stubindex.*
 import org.jetbrains.kotlin.idea.util.application.runReadAction
+import org.jetbrains.kotlin.idea.vfilefinder.KotlinPackageSourcesMemberNamesIndex
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.psi.*
@@ -61,9 +63,12 @@ class StubBasedPackageMemberDeclarationProvider(
         return result
     }
 
-    private val declarationNames_ by lazy(LazyThreadSafetyMode.PUBLICATION) {
-        getDeclarations(DescriptorKindFilter.ALL, { true })
-                .mapTo(mutableSetOf()) { ResolveSessionUtils.safeNameForLazyResolve(it as KtNamedDeclaration) }
+    private val declarationNames_: Set<Name> by lazy(LazyThreadSafetyMode.PUBLICATION) {
+        FileBasedIndex.getInstance()
+                .getValues(KotlinPackageSourcesMemberNamesIndex.KEY, fqName.asString(), searchScope)
+                .flatMapTo(hashSetOf()) {
+                    it.map { stringName -> ResolveSessionUtils.safeNameForLazyResolve(Name.identifier(stringName)) }
+                }
     }
 
     override fun getDeclarationNames() = declarationNames_

idea/idea-analysis/src/org/jetbrains/kotlin/idea/vfilefinder/KotlinPackageSourcesMemberNamesIndex.kt

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.idea.vfilefinder
+
+import com.intellij.util.indexing.*
+import com.intellij.util.io.DataExternalizer
+import com.intellij.util.io.EnumeratorStringDescriptor
+import org.jetbrains.kotlin.idea.KotlinFileType
+import org.jetbrains.kotlin.psi.KtDeclaration
+import org.jetbrains.kotlin.psi.KtFile
+import java.io.DataInput
+import java.io.DataOutput
+
+object KotlinPackageSourcesMemberNamesIndex : FileBasedIndexExtension<String, Collection<String>>() {
+    val KEY: ID<String, Collection<String>> = ID.create(KotlinPackageSourcesMemberNamesIndex::class.java.canonicalName)
+
+    private val KEY_DESCRIPTOR = EnumeratorStringDescriptor()
+
+    override fun getName() = KEY
+
+    override fun dependsOnFileContent() = true
+
+    override fun getKeyDescriptor() = KEY_DESCRIPTOR
+
+    override fun getValueExternalizer() = StringSetExternalizer
+
+    override fun getInputFilter(): FileBasedIndex.InputFilter =
+            FileBasedIndex.InputFilter { file -> file.extension == KotlinFileType.EXTENSION }
+
+    override fun getVersion(): Int = 1
+
+    override fun getIndexer(): DataIndexer<String, Collection<String>, FileContent> =
+        DataIndexer { inputData ->
+            val ktFile = inputData.psiFile as KtFile
+            val packageName = ktFile.packageDirective?.fqName?.asString() ?: ""
+
+            mapOf(packageName to ktFile.declarations.mapNotNullTo(hashSetOf(), KtDeclaration::getName))
+        }
+}
+
+object StringSetExternalizer : DataExternalizer<Collection<String>> {
+    private val ELEMENTS_SERIALIZER = EnumeratorStringDescriptor()
+
+    override fun read(input: DataInput): Set<String> {
+        val size = input.readInt()
+        return hashSetOf<String>().apply {
+            repeat(size) {
+                add(ELEMENTS_SERIALIZER.read(input))
+            }
+        }
+    }
+
+    override fun save(output: DataOutput, value: Collection<String>) {
+        output.writeInt(value.size)
+        value.toSet().forEach { ELEMENTS_SERIALIZER.save(output, it) }
+    }
+}

idea/src/META-INF/plugin.xml

@@ -748,6 +748,7 @@
     <fileBasedIndex implementation="org.jetbrains.kotlin.idea.vfilefinder.KotlinMetadataFileIndex"/>
     <fileBasedIndex implementation="org.jetbrains.kotlin.idea.vfilefinder.KotlinMetadataFilePackageIndex"/>
     <fileBasedIndex implementation="org.jetbrains.kotlin.idea.vfilefinder.KotlinModuleMappingIndex"/>
+    <fileBasedIndex implementation="org.jetbrains.kotlin.idea.vfilefinder.KotlinPackageSourcesMemberNamesIndex"/>
 
     <idIndexer filetype="Kotlin" implementationClass="org.jetbrains.kotlin.idea.search.KotlinIdIndexer"/>
     <todoIndexer filetype="Kotlin" implementationClass="org.jetbrains.kotlin.idea.search.KotlinTodoIndexer"/>

idea/src/org/jetbrains/kotlin/idea/versions/KotlinUpdatePluginComponent.kt

@@ -58,6 +58,7 @@ class KotlinUpdatePluginComponent : ApplicationComponent {
             fileBasedIndex.requestRebuild(KotlinMetadataFileIndex.KEY)
             fileBasedIndex.requestRebuild(KotlinMetadataFilePackageIndex.KEY)
             fileBasedIndex.requestRebuild(KotlinModuleMappingIndex.KEY)
+            fileBasedIndex.requestRebuild(KotlinPackageSourcesMemberNamesIndex.KEY)
 
             PropertiesComponent.getInstance()?.setValue(INSTALLED_KOTLIN_VERSION, KotlinPluginUtil.getPluginVersion())
         }