New J2K: do not print qualified names if corresponding qualifier can unambiguously resolved

This speeds up shortening qualified references phase

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/postProcessing/processings/ShortenReferenceProcessing.kt

@@ -8,7 +8,7 @@ package org.jetbrains.kotlin.nj2k.postProcessing.processings
 import com.intellij.openapi.editor.RangeMarker
 import com.intellij.psi.PsiElement
 import org.jetbrains.kotlin.idea.core.ShortenReferences
-import org.jetbrains.kotlin.nj2k.ImportStorage
+import org.jetbrains.kotlin.nj2k.JKImportStorage
 import org.jetbrains.kotlin.nj2k.NewJ2kConverterContext
 import org.jetbrains.kotlin.nj2k.postProcessing.GeneralPostProcessing
 import org.jetbrains.kotlin.nj2k.postProcessing.runUndoTransparentActionInEdt
@@ -19,7 +19,7 @@ class ShortenReferenceProcessing : GeneralPostProcessing {
     private val filter = filter@{ element: PsiElement ->
         when (element) {
             is KtQualifiedExpression -> when {
-                ImportStorage.isImportNeededForCall(element) -> ShortenReferences.FilterResult.PROCESS
+                JKImportStorage.isImportNeededForCall(element) -> ShortenReferences.FilterResult.PROCESS
                 else -> ShortenReferences.FilterResult.SKIP
             }
             else -> ShortenReferences.FilterResult.PROCESS

nj2k/src/org/jetbrains/kotlin/nj2k/JKImportStorage.kt

@@ -13,7 +13,7 @@ import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.psi.KtQualifiedExpression
 import org.jetbrains.kotlin.resolve.calls.callUtil.getCalleeExpressionIfAny
 
-class ImportStorage {
+class JKImportStorage {
     private val imports = mutableSetOf<FqName>()
 
     fun addImport(import: FqName) {
@@ -22,6 +22,10 @@ class ImportStorage {
         }
     }
 
+    fun addImport(import: String) {
+        addImport(FqName(import))
+    }
+
     fun getImports(): Set<FqName> = imports
 
     companion object {

nj2k/src/org/jetbrains/kotlin/nj2k/JKSymbolRenderer.kt

@@ -0,0 +1,88 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.nj2k
+
+import com.intellij.openapi.project.Project
+import com.intellij.psi.search.GlobalSearchScope
+import com.intellij.psi.search.PsiShortNamesCache
+import com.intellij.util.Processor
+import org.jetbrains.kotlin.builtins.KotlinBuiltIns
+import org.jetbrains.kotlin.name.SpecialNames
+import org.jetbrains.kotlin.nj2k.symbols.*
+import org.jetbrains.kotlin.nj2k.tree.JKClassAccessExpression
+import org.jetbrains.kotlin.nj2k.tree.JKQualifiedExpression
+import org.jetbrains.kotlin.nj2k.tree.JKTreeElement
+import org.jetbrains.kotlin.utils.addToStdlib.safeAs
+
+class JKSymbolRenderer(private val importStorage: JKImportStorage, project: Project) {
+    private val canBeShortenedClassNameCache = CanBeShortenedCache(project)
+
+    private fun JKSymbol.isFqNameExpected(owner: JKTreeElement?): Boolean {
+        if (owner?.isSelectorOfQualifiedExpression() == true) return false
+        return this is JKClassSymbol || isStaticMember || isEnumConstant
+    }
+
+    private fun JKSymbol.isFromJavaLangPackage() =
+        fqName.startsWith(JAVA_LANG_FQ_PREFIX)
+
+    fun renderSymbol(symbol: JKSymbol, owner: JKTreeElement?): String {
+        val name = symbol.name.escaped()
+        if (!symbol.isFqNameExpected(owner)) return name
+        val fqName = symbol.getDisplayFqName().escapedAsQualifiedName()
+        if (owner is JKClassAccessExpression && symbol.isFromJavaLangPackage()) return fqName
+
+        return when {
+            symbol is JKClassSymbol && canBeShortenedClassNameCache.canBeShortened(symbol) -> {
+                importStorage.addImport(fqName)
+                name
+            }
+            symbol.isStaticMember && symbol.containingClass?.isUnnamedCompanion == true -> {
+                val containingClass = symbol.containingClass ?: return fqName
+                val classContainingCompanion = containingClass.containingClass ?: return fqName
+                if (!canBeShortenedClassNameCache.canBeShortened(classContainingCompanion)) return fqName
+                importStorage.addImport(classContainingCompanion.getDisplayFqName())
+                "${classContainingCompanion.name.escaped()}.${SpecialNames.DEFAULT_NAME_FOR_COMPANION_OBJECT}.$name"
+            }
+
+            symbol.isEnumConstant || symbol.isStaticMember -> {
+                val containingClass = symbol.containingClass ?: return fqName
+                if (!canBeShortenedClassNameCache.canBeShortened(containingClass)) return fqName
+                importStorage.addImport(containingClass.getDisplayFqName())
+                "${containingClass.name.escaped()}.$name"
+            }
+
+            else -> fqName
+        }
+    }
+
+    private fun JKTreeElement.isSelectorOfQualifiedExpression() =
+        parent?.safeAs<JKQualifiedExpression>()?.selector == this
+
+    companion object {
+        private const val JAVA_LANG_FQ_PREFIX = "java.lang"
+    }
+}
+
+private class CanBeShortenedCache(project: Project) {
+    private val shortNameCache = PsiShortNamesCache.getInstance(project)
+    private val searchScope = GlobalSearchScope.allScope(project)
+    private val canBeShortenedCache = mutableMapOf<String, Boolean>().apply {
+        CLASS_NAMES_WHICH_HAVE_DIFFERENT_MEANINGS_IN_KOTLIN_AND_JAVA.forEach { name ->
+            this[name] = false
+        }
+    }
+
+    fun canBeShortened(symbol: JKClassSymbol): Boolean = canBeShortenedCache.getOrPut(symbol.name) {
+        !shortNameCache.processClassesWithName(symbol.name, Processor.FALSE, searchScope, null)
+    }
+
+    companion object {
+        private val CLASS_NAMES_WHICH_HAVE_DIFFERENT_MEANINGS_IN_KOTLIN_AND_JAVA = setOf(
+            "Function",
+            "Serializable"
+        )
+    }
+}

nj2k/src/org/jetbrains/kotlin/nj2k/JavaToJKTreeBuilder.kt

@@ -57,7 +57,7 @@ class JavaToJKTreeBuilder constructor(
     private val symbolProvider: JKSymbolProvider,
     private val typeFactory: JKTypeFactory,
     converterServices: NewJavaToKotlinServices,
-    private val importStorage: ImportStorage
+    private val importStorage: JKImportStorage
 ) {
     private fun PsiType?.toJK(): JKType {
         if (this == null) return JKNoType

nj2k/src/org/jetbrains/kotlin/nj2k/NewCodeBuilder.kt

@@ -5,8 +5,10 @@
 
 package org.jetbrains.kotlin.nj2k
 
+import com.intellij.openapi.project.Project
 import org.jetbrains.kotlin.j2k.ast.Nullability
-import org.jetbrains.kotlin.nj2k.symbols.*
+import org.jetbrains.kotlin.nj2k.symbols.JKSymbol
+import org.jetbrains.kotlin.nj2k.symbols.getDisplayFqName
 import org.jetbrains.kotlin.nj2k.tree.*
 import org.jetbrains.kotlin.nj2k.tree.visitors.JKVisitorWithCommentsPrinting
 import org.jetbrains.kotlin.nj2k.types.*
@@ -15,7 +17,7 @@ import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 
 class NewCodeBuilder(context: NewJ2kConverterContext) {
     private val elementInfoStorage = context.elementsInfoStorage
-    private val printer = JKPrinter(elementInfoStorage)
+    private val printer = JKPrinter(context.project, context.importStorage, elementInfoStorage)
 
     private fun classKindString(kind: JKClass.ClassKind): String = when (kind) {
         JKClass.ClassKind.ANNOTATION -> "annotation class"
@@ -689,7 +691,7 @@ class NewCodeBuilder(context: NewJ2kConverterContext) {
             printer.print("::")
             val needFqName = methodReferenceExpression.qualifier is JKStubExpression
             val displayName =
-                if (needFqName) methodReferenceExpression.identifier.getDisplayName()
+                if (needFqName) methodReferenceExpression.identifier.getDisplayFqName()
                 else methodReferenceExpression.identifier.name
 
             printer.print(displayName.escapedAsQualifiedName())
@@ -816,7 +818,7 @@ class NewCodeBuilder(context: NewJ2kConverterContext) {
 
         override fun visitAnnotationRaw(annotation: JKAnnotation) {
             printer.print("@")
-            printer.print(annotation.classSymbol.fqName.escapedAsQualifiedName())
+            printer.renderSymbol(annotation.classSymbol, annotation)
             if (annotation.arguments.isNotEmpty()) {
                 printer.par {
                     printer.renderList(annotation.arguments) { it.accept(this) }
@@ -880,9 +882,13 @@ enum class ParenthesisKind(val open: String, val close: String) {
     ANGLE("<", ">")
 }
 
+
 private class JKPrinter(
+    project: Project,
+    importStorage: JKImportStorage,
     private val elementInfoStorage: JKElementInfoStorage
 ) {
+    val symbolRenderer = JKSymbolRenderer(importStorage, project)
     private val stringBuilder: StringBuilder = StringBuilder()
     private var currentIndent = 0;
     private val indentSymbol = " ".repeat(4)
@@ -921,15 +927,11 @@ private class JKPrinter(
     }
 
     inline fun par(kind: ParenthesisKind = ParenthesisKind.ROUND, body: () -> Unit) {
-        this.print(kind.open)
+        print(kind.open)
         body()
-        this.print(kind.close)
+        print(kind.close)
     }
 
-    private fun JKSymbol.needFqName(): Boolean {
-        if (this !is JKClassSymbol && !isStaticMember && !isEnumConstant) return false
-        return fqName !in mappedToKotlinFqNames
-    }
 
     private fun JKType.renderTypeInfo() {
         this@JKPrinter.print(elementInfoStorage.getOrCreateInfoForElement(this).render())
@@ -984,9 +986,7 @@ private class JKPrinter(
     }
 
     fun renderSymbol(symbol: JKSymbol, owner: JKTreeElement?) {
-        val needFqName = symbol.needFqName() && owner?.isSelectorOfQualifiedExpression() != true
-        val displayName = if (needFqName) symbol.getDisplayName() else symbol.name
-        this.print(displayName.escapedAsQualifiedName())
+        print(symbolRenderer.renderSymbol(symbol, owner))
     }
 
     inline fun <T> renderList(list: List<T>, separator: String = ", ", renderElement: (T) -> Unit) =
@@ -1000,13 +1000,10 @@ private class JKPrinter(
             renderElement(it)
         }
     }
-
-    private fun JKTreeElement.isSelectorOfQualifiedExpression() =
-        parent?.safeAs<JKQualifiedExpression>()?.selector == this
 }
 
 
-private fun String.escapedAsQualifiedName(): String =
+fun String.escapedAsQualifiedName(): String =
     split('.')
         .map { it.escaped() }
         .joinToString(".") { it }
@@ -1016,14 +1013,3 @@ private fun <T> List<T>.headTail(): Pair<T?, List<T>?> {
     val tail = if (size <= 1) null else subList(1, size)
     return head to tail
 }
-
-
-private val mappedToKotlinFqNames =
-    setOf(
-        "java.util.ArrayList",
-        "java.util.LinkedHashMap",
-        "java.util.HashMap",
-        "java.util.LinkedHashSet",
-        "java.util.HashSet"
-    )
-

nj2k/src/org/jetbrains/kotlin/nj2k/NewJ2kConverterContext.kt

@@ -15,7 +15,7 @@ data class NewJ2kConverterContext(
     val typeFactory: JKTypeFactory,
     val converter: NewJavaToKotlinConverter,
     val inConversionContext: (PsiElement) -> Boolean,
-    val importStorage: ImportStorage,
+    val importStorage: JKImportStorage,
     val elementsInfoStorage: JKElementInfoStorage
 ) : ConverterContext {
     val project: Project

nj2k/src/org/jetbrains/kotlin/nj2k/NewJavaToKotlinConverter.kt

@@ -102,7 +102,7 @@ class NewJavaToKotlinConverter(
         val typeFactory = JKTypeFactory(symbolProvider)
         symbolProvider.typeFactory = typeFactory
         symbolProvider.preBuildTree(inputElements)
-        val importStorage = ImportStorage()
+        val importStorage = JKImportStorage()
         val treeBuilder = JavaToJKTreeBuilder(symbolProvider, typeFactory, converterServices, importStorage)
 
 

nj2k/src/org/jetbrains/kotlin/nj2k/conversions/FilterImportsConversion.kt

@@ -5,7 +5,7 @@
 
 package org.jetbrains.kotlin.nj2k.conversions
 
-import org.jetbrains.kotlin.nj2k.ImportStorage
+import org.jetbrains.kotlin.nj2k.JKImportStorage
 import org.jetbrains.kotlin.nj2k.NewJ2kConverterContext
 import org.jetbrains.kotlin.nj2k.tree.JKImportList
 import org.jetbrains.kotlin.nj2k.tree.JKTreeElement
@@ -14,7 +14,7 @@ class FilterImportsConversion(context: NewJ2kConverterContext) : RecursiveApplic
     override fun applyToElement(element: JKTreeElement): JKTreeElement {
         if (element !is JKImportList) return recurse(element)
         element.imports = element.imports.filter { import ->
-            ImportStorage.isImportNeeded(import.name.value)
+            JKImportStorage.isImportNeeded(import.name.value)
         }
         return recurse(element)
     }

nj2k/src/org/jetbrains/kotlin/nj2k/symbols/utils.kt

@@ -12,6 +12,7 @@ import com.intellij.psi.PsiMethod
 import com.intellij.psi.PsiModifierListOwner
 import org.jetbrains.kotlin.idea.refactoring.fqName.getKotlinFqName
 import org.jetbrains.kotlin.idea.search.declarationsSearch.findDeepestSuperMethodsNoWrapping
+import org.jetbrains.kotlin.name.SpecialNames
 import org.jetbrains.kotlin.nj2k.isObjectOrCompanionObject
 import org.jetbrains.kotlin.nj2k.psi
 import org.jetbrains.kotlin.nj2k.tree.*
@@ -23,7 +24,7 @@ import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 val JKSymbol.isUnresolved
     get() = this is JKUnresolvedSymbol
 
-fun JKSymbol.getDisplayName(): String {
+fun JKSymbol.getDisplayFqName(): String {
     fun JKSymbol.isDisplayable() = this is JKClassSymbol || this is JKPackageSymbol
     if (this !is JKUniverseSymbol<*>) return fqName
     return generateSequence(declaredIn?.takeIf { it.isDisplayable() }) { symbol ->
@@ -31,11 +32,6 @@ fun JKSymbol.getDisplayName(): String {
     }.fold(name) { acc, symbol -> "${symbol.name}.$acc" }
 }
 
-fun JKSymbol.fqNameToImport(): String? = when {
-    this is JKClassSymbol && this !is JKUniverseClassSymbol -> fqName
-    else -> null
-}
-
 fun JKSymbol.deepestFqName(): String? {
     fun Any.deepestFqNameForTarget(): String? =
         when (this) {
@@ -47,6 +43,9 @@ fun JKSymbol.deepestFqName(): String? {
     return target.deepestFqNameForTarget() ?: fqName
 }
 
+val JKSymbol.containingClass
+    get() = declaredIn as? JKClassSymbol
+
 val JKSymbol.isStaticMember
     get() = when (val target = target) {
         is PsiModifierListOwner -> target.hasModifier(JvmModifier.STATIC)
@@ -66,3 +65,11 @@ val JKSymbol.isEnumConstant
         is KtEnumEntry -> true
         else -> false
     }
+
+val JKSymbol.isUnnamedCompanion
+    get() = when (val target = target) {
+        is JKClass -> target.classKind == JKClass.ClassKind.COMPANION
+        is KtObjectDeclaration -> target.isCompanion() && target.name == SpecialNames.DEFAULT_NAME_FOR_COMPANION_OBJECT.toString()
+        else -> false
+    }
+

nj2k/testData/copyPaste/SeveralMethodsSample.expected.kt

@@ -18,8 +18,7 @@ class A {
                 }
             }
         }
-        assert(element is PsiMethod
-        ) { "Method accepts only kotlin functions/properties and java methods, but '" + element.getText().toString() + "' was found" }
+        assert(element is PsiMethod) { "Method accepts only kotlin functions/properties and java methods, but '" + element.getText().toString() + "' was found" }
         return JetRefactoringUtil.formatPsiMethod(element as PsiMethod, true, false)
     }
 

nj2k/testData/newJ2k/annotations/jetbrainsNotNull.kt

@@ -1,4 +1,3 @@
-// ERROR: Unresolved reference: Test
 // !forceNotNullTypes: false
 // !specifyLocalVariableTypeByDefault: true
 package test
@@ -18,7 +17,7 @@ class Test(str: String) {
         val test = "String2"
         sout(test)
         sout(dummy(test))
-        test.Test(test)
+        Test(test)
     }
 
     init {

nj2k/testData/newJ2k/annotations/jetbrainsNullable.kt

@@ -1,4 +1,3 @@
-// ERROR: Unresolved reference: Test
 // !specifyLocalVariableTypeByDefault: true
 package test
 
@@ -17,7 +16,7 @@ class Test(str: String?) {
         val test = "String2"
         sout(test)
         sout(dummy(test))
-        test.Test(test)
+        Test(test)
     }
 
     init {

nj2k/testData/newJ2k/constructors/nestedClassNameInParameterDefaults2.kt

@@ -1,3 +1,5 @@
+import A.Nested
+
 internal class A @JvmOverloads constructor(nested: Nested? = Nested(Nested.FIELD)) {
     internal class Nested(p: Int) {
         companion object {
@@ -7,5 +9,5 @@ internal class A @JvmOverloads constructor(nested: Nested? = Nested(Nested.FIELD
 }
 
 internal class B {
-    var nested: A.Nested? = null
+    var nested: Nested? = null
 }

nj2k/testData/newJ2k/constructors/nestedClassNameInParameterDefaults3.kt

@@ -1,5 +1,7 @@
 package pack
 
+import pack.A.Nested
+
 internal class A @JvmOverloads constructor(nested: Nested? = Nested(Nested.FIELD)) {
     internal class Nested(p: Int) {
         companion object {
@@ -9,5 +11,5 @@ internal class A @JvmOverloads constructor(nested: Nested? = Nested(Nested.FIELD
 }
 
 internal class B {
-    var nested: A.Nested? = null
+    var nested: Nested? = null
 }

nj2k/testData/newJ2k/constructors/nestedClassNameInParameterDefaults4.kt

@@ -1,5 +1,7 @@
 package pack
 
+import pack.A.Nested
+
 internal class A @JvmOverloads constructor(nested: Nested? = Nested(Nested.FIELD)) {
     internal class Nested(p: Int) {
         companion object {
@@ -9,5 +11,5 @@ internal class A @JvmOverloads constructor(nested: Nested? = Nested(Nested.FIELD
 }
 
 internal class B {
-    var nested: A.Nested? = null
+    var nested: Nested? = null
 }

nj2k/testData/newJ2k/issues/kt-19296.kt

@@ -1,3 +1,5 @@
+import A.I
+
 open class A {
     interface I {
         fun f()
@@ -6,5 +8,5 @@ open class A {
 
 class B : A()
 class Test {
-    var z: A.I? = null
+    var z: I? = null
 }

nj2k/testData/newJ2k/issues/kt-24677.kt

@@ -1,5 +1,7 @@
+import Foo.SomeClass
+
 internal interface FooInterface {
-    fun foo(): ArrayList<out Foo.SomeClass?>?
+    fun foo(): ArrayList<out SomeClass?>?
 }
 
 class Foo : FooInterface {

nj2k/testData/newJ2k/javaStreamsApi/formatting.kt

@@ -1,4 +1,3 @@
-import java.util.Comparator
 import java.util.stream.Collectors
 
 internal class Test {

nj2k/testData/newJ2k/javaStreamsApi/streamOperations.kt

@@ -1,4 +1,3 @@
-import java.util.Comparator
 import java.util.stream.Collectors
 
 internal class Test {

nj2k/testData/newJ2k/newClassExpression/newStaticInnerClass.kt

@@ -1,11 +1,13 @@
 package demo
 
+import demo.Foo.Bar
+
 internal class Foo {
     internal class Bar
 }
 
 internal class User {
     fun main() {
-        val boo = Foo.Bar()
+        val boo = Bar()
     }
 }