FIR IDE: introduce package symbol

idea/idea-frontend-api/src/org/jetbrains/kotlin/idea/frontend/api/symbols/KtPackageSymbol.kt

@@ -0,0 +1,12 @@
+/*
+ * Copyright 2010-2020 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.idea.frontend.api.symbols
+
+import org.jetbrains.kotlin.name.FqName
+
+abstract class KtPackageSymbol : KtSymbol {
+    abstract val fqName: FqName
+}

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/KtFirAnalysisSession.kt

@@ -40,6 +40,7 @@ class KtFirAnalysisSession(
     internal val firSymbolBuilder = KtSymbolByFirBuilder(
         element.session.firSymbolProvider,
         ConeTypeCheckerContext(isErrorTypeEqualsToAnything = true, isStubTypeEqualsToAnything = true, element.session),
+        element.project,
         validityToken
     )
 

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/KtSymbolByFirBuilder.kt

@@ -5,6 +5,8 @@
 
 package org.jetbrains.kotlin.idea.frontend.api.fir
 
+import com.intellij.openapi.project.Project
+import com.intellij.psi.search.GlobalSearchScope
 import com.intellij.util.containers.ContainerUtil
 import org.jetbrains.kotlin.fir.FirElement
 import org.jetbrains.kotlin.fir.declarations.*
@@ -28,6 +30,10 @@ import org.jetbrains.kotlin.idea.frontend.api.fir.utils.weakRef
 import org.jetbrains.kotlin.idea.frontend.api.symbols.KtClassLikeSymbol
 import org.jetbrains.kotlin.idea.frontend.api.symbols.KtSymbol
 import org.jetbrains.kotlin.idea.frontend.api.symbols.KtTypeParameterSymbol
+import org.jetbrains.kotlin.idea.frontend.api.symbols.KtVariableSymbol
+import org.jetbrains.kotlin.idea.frontend.api.types.KtType
+import org.jetbrains.kotlin.idea.stubindex.PackageIndexUtil
+import org.jetbrains.kotlin.name.FqName
 
 internal class KtSymbolByFirBuilder(
     firProvider: FirSymbolProvider,
@@ -99,7 +105,7 @@ internal class KtSymbolByFirBuilder(
 
 
     fun createPackageSymbolIfOneExists(packageFqName: FqName): KtFirPackageSymbol? {
-        val exists = firProvider.getPackage(packageFqName) != null
+        val exists = PackageIndexUtil.packageExists(packageFqName, GlobalSearchScope.allScope(project), project)
         if (!exists) {
             return null
         }

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/symbols/KtFirPackageSymbol.kt

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2010-2020 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.idea.frontend.api.fir.symbols
+
+import com.intellij.openapi.project.Project
+import com.intellij.psi.PsiElement
+import com.intellij.psi.PsiManager
+import com.intellij.psi.impl.file.PsiPackageImpl
+import com.intellij.psi.search.GlobalSearchScope
+import org.jetbrains.kotlin.idea.frontend.api.ValidityOwner
+import org.jetbrains.kotlin.idea.frontend.api.ValidityOwnerByValidityToken
+import org.jetbrains.kotlin.idea.frontend.api.fir.KtFirAnalysisSession
+import org.jetbrains.kotlin.idea.frontend.api.fir.utils.cached
+import org.jetbrains.kotlin.idea.frontend.api.symbols.KtPackageSymbol
+import org.jetbrains.kotlin.idea.frontend.api.symbols.KtSymbolOrigin
+import org.jetbrains.kotlin.idea.frontend.api.symbols.KtSymbolPointer
+import org.jetbrains.kotlin.idea.frontend.api.symbols.symbolPointer
+import org.jetbrains.kotlin.idea.stubindex.PackageIndexUtil
+import org.jetbrains.kotlin.name.FqName
+
+class KtFirPackageSymbol(
+    override val fqName: FqName,
+    private val project: Project,
+    override val token: ValidityOwner
+) : KtPackageSymbol(), ValidityOwnerByValidityToken {
+    override val psi: PsiElement by cached {
+        KtPackage(PsiManager.getInstance(project), fqName, GlobalSearchScope.allScope(project))
+    }
+
+    override val origin: KtSymbolOrigin
+        get() = KtSymbolOrigin.SOURCE // TODO
+
+    override fun createPointer(): KtSymbolPointer<KtPackageSymbol> = symbolPointer { session ->
+        check(session is KtFirAnalysisSession)
+        session.firSymbolBuilder.createPackageSymbolIfOneExists(fqName)
+    }
+}
+
+class KtPackage(
+    manager: PsiManager,
+    private val fqName: FqName,
+    private val scope: GlobalSearchScope
+) : PsiPackageImpl(manager, fqName.asString()) {
+    override fun copy() = KtPackage(manager, fqName, scope)
+
+    override fun isValid(): Boolean = PackageIndexUtil.packageExists(fqName, scope, project)
+}

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/references/FirReferenceResolveHelper.kt

@@ -20,10 +20,15 @@ import org.jetbrains.kotlin.fir.types.FirResolvedTypeRef
 import org.jetbrains.kotlin.idea.fir.*
 import org.jetbrains.kotlin.idea.frontend.api.fir.KtSymbolByFirBuilder
 import org.jetbrains.kotlin.idea.frontend.api.fir.buildSymbol
+import org.jetbrains.kotlin.idea.frontend.api.fir.symbols.KtFirPackageSymbol
 import org.jetbrains.kotlin.idea.frontend.api.symbols.KtSymbol
 import org.jetbrains.kotlin.name.ClassId
+import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.psi.psiUtil.collectDescendantsOfType
 import org.jetbrains.kotlin.psi.psiUtil.getNonStrictParentOfType
+import org.jetbrains.kotlin.psi.psiUtil.getQualifiedExpressionForSelector
+import org.jetbrains.kotlin.psi.psiUtil.getQualifiedExpressionForSelectorOrThis
 
 internal object FirReferenceResolveHelper {
     fun FirResolvedTypeRef.toTargetSymbol(session: FirSession, symbolBuilder: KtSymbolByFirBuilder): KtSymbol? {
@@ -81,6 +86,20 @@ internal object FirReferenceResolveHelper {
         }
     }
 
+    private fun getPackageSymbolFor(expression: KtSimpleNameExpression, symbolBuilder: KtSymbolByFirBuilder): KtFirPackageSymbol? {
+        val fqName = when (val qualified = expression.getQualifiedExpressionForSelector()) {
+            null -> FqName(expression.getReferencedName())
+            else -> {
+                qualified
+                    .collectDescendantsOfType<KtSimpleNameExpression>()
+                    .joinToString(separator = ".") { it.getReferencedName() }
+                    .let(::FqName)
+            }
+        }
+
+        return symbolBuilder.createPackageSymbolIfOneExists(fqName)
+    }
+
     internal fun resolveSimpleNameReference(
         ref: KtFirSimpleNameReference,
         symbolBuilder: KtSymbolByFirBuilder
@@ -135,12 +154,11 @@ internal object FirReferenceResolveHelper {
                     if (parent.selectorExpression !== expression) {
                         // Special: package reference in the middle of import directive
                         // import a.<caret>b.c.SomeClass
-                        // TODO: return reference to PsiPackage
+                        return listOfNotNull(getPackageSymbolFor(expression, symbolBuilder)?.let { return listOf(it) })
-//                        return listOf(expression)
-                        return emptyList()
                     }
                     parent = parent.parent
                 }
+
                 val classId = fir.resolvedClassId
                 if (classId != null) {
                     return listOfNotNull(classId.toTargetPsi(session, symbolBuilder))
@@ -162,8 +180,7 @@ internal object FirReferenceResolveHelper {
             is FirFile -> {
                 if (expression.getNonStrictParentOfType<KtPackageDirective>() != null) {
                     // Special: package reference in the middle of package directive
-                    return emptyList()
+                    return listOfNotNull(getPackageSymbolFor(expression, symbolBuilder))
-//                    return listOf(expression)
                 }
                 return listOf(symbolBuilder.buildSymbol(fir))
             }