FIR/UAST: commonize UImportStatement

plugins/uast-kotlin-base/src/org/jetbrains/uast/kotlin/BaseKotlinUastResolveProviderService.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.uast.kotlin
 
 import com.intellij.psi.PsiElement
+import org.jetbrains.kotlin.psi.KtExpression
 import org.jetbrains.uast.UElement
 
 interface BaseKotlinUastResolveProviderService {
@@ -13,4 +14,5 @@ interface BaseKotlinUastResolveProviderService {
 
     fun convertParent(uElement: UElement): UElement?
 
+    fun resolveToDeclaration(ktExpression: KtExpression): PsiElement?
 }

plugins/uast-kotlin-base/src/org/jetbrains/uast/kotlin/declarations/KotlinUImportStatement.kt

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2010-2021 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.uast.kotlin
+
+import com.intellij.psi.PsiElement
+import org.jetbrains.kotlin.psi.KtExpression
+import org.jetbrains.kotlin.psi.KtImportDirective
+import org.jetbrains.kotlin.psi.KtReferenceExpression
+import org.jetbrains.kotlin.psi.psiUtil.getQualifiedElementSelector
+import org.jetbrains.uast.UElement
+import org.jetbrains.uast.UImportStatement
+import org.jetbrains.uast.USimpleNameReferenceExpression
+import org.jetbrains.uast.kotlin.internal.DelegatedMultiResolve
+
+class KotlinUImportStatement(
+    override val psi: KtImportDirective,
+    givenParent: UElement?
+) : KotlinAbstractUElement(givenParent), UImportStatement, DelegatedMultiResolve {
+
+    override val javaPsi: PsiElement? = null
+
+    override val sourcePsi: KtImportDirective = psi
+
+    override val isOnDemand: Boolean = sourcePsi.isAllUnder
+
+    private val importRef: ImportReference? by lz {
+        sourcePsi.importedReference?.let {
+            ImportReference(it, sourcePsi.name ?: sourcePsi.text, this, sourcePsi)
+        }
+    }
+
+    override val importReference: UElement? = importRef
+
+    override fun resolve(): PsiElement? = importRef?.resolve()
+
+    private class ImportReference(
+        override val psi: KtExpression,
+        override val identifier: String,
+        givenParent: UElement?,
+        private val importDirective: KtImportDirective
+    ) : KotlinAbstractUExpression(givenParent), USimpleNameReferenceExpression {
+        override val sourcePsi: KtExpression = psi
+
+        override val resolvedName: String = identifier
+
+        override fun asRenderString(): String = importDirective.importedFqName?.asString() ?: sourcePsi.text
+
+        override fun resolve(): PsiElement? {
+            val reference = sourcePsi.getQualifiedElementSelector() as? KtReferenceExpression ?: return null
+            return baseResolveProviderService?.resolveToDeclaration(reference)
+        }
+    }
+}

plugins/uast-kotlin-base/src/org/jetbrains/uast/kotlin/internal/DelegatedMultiResolve.kt

@@ -0,0 +1,16 @@
+/*
+ * Copyright 2010-2021 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.uast.kotlin.internal
+
+import com.intellij.psi.PsiSubstitutor
+import com.intellij.psi.ResolveResult
+import com.intellij.psi.infos.CandidateInfo
+import org.jetbrains.uast.UMultiResolvable
+import org.jetbrains.uast.UResolvable
+
+interface DelegatedMultiResolve : UMultiResolvable, UResolvable {
+    override fun multiResolve(): Iterable<ResolveResult> = listOfNotNull(resolve()?.let { CandidateInfo(it, PsiSubstitutor.EMPTY) })
+}