New J2K: make post-processing aware of other files which are being converted

Before post-processing was able to handle only one converting file at once
So, some conversions (like (field, getter, setter) to Kotlin property)
was not able to work when converting class hierarchy was split into
multiple files.
Also, inferring nullability for a set of files was broken

#KT-19569 fixed
#KT-34266 fixed
#KT-32518 fixed

j2k/src/org/jetbrains/kotlin/j2k/AfterConversionPass.kt

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.j2k
 
+import com.intellij.openapi.editor.RangeMarker
 import com.intellij.openapi.project.Project
 import com.intellij.openapi.util.TextRange
 import org.jetbrains.kotlin.idea.util.application.runReadAction
@@ -29,14 +30,19 @@ class AfterConversionPass(val project: Project, val postProcessor: PostProcessor
         range: TextRange?,
         onPhaseChanged: ((Int, String) -> Unit)? = null
     ) {
-        val rangeMarker = if (range != null) {
-            val document = kotlinFile.viewProvider.document!!
-            val marker = runReadAction { document.createRangeMarker(range.startOffset, range.endOffset) }
-            marker.isGreedyToLeft = true
-            marker.isGreedyToRight = true
-            marker
-        } else null
-
-        postProcessor.doAdditionalProcessing(kotlinFile, converterContext, rangeMarker, onPhaseChanged)
+        postProcessor.doAdditionalProcessing(
+            when {
+                range != null -> JKPieceOfCodePostProcessingTarget(kotlinFile, range.toRangeMarker(kotlinFile))
+                else -> JKMultipleFilesPostProcessingTarget(listOf(kotlinFile))
+            },
+            converterContext,
+            onPhaseChanged
+        )
     }
 }
+
+fun TextRange.toRangeMarker(file: KtFile): RangeMarker =
+    runReadAction { file.viewProvider.document!!.createRangeMarker(startOffset, endOffset) }.apply {
+        isGreedyToLeft = true
+        isGreedyToRight = true
+    }

j2k/src/org/jetbrains/kotlin/j2k/JavaToKotlinConverter.kt

@@ -26,12 +26,15 @@ import com.intellij.openapi.util.Computable
 import com.intellij.psi.*
 import com.intellij.psi.impl.source.DummyHolder
 import org.jetbrains.kotlin.idea.KotlinLanguage
+import org.jetbrains.kotlin.idea.core.util.range
+import org.jetbrains.kotlin.idea.util.application.runReadAction
 import org.jetbrains.kotlin.j2k.ast.Element
 import org.jetbrains.kotlin.j2k.usageProcessing.ExternalCodeProcessor
 import org.jetbrains.kotlin.j2k.usageProcessing.UsageProcessing
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.psi.KtPsiFactory
+import org.jetbrains.kotlin.psi.psiUtil.elementsInRange
 import org.jetbrains.kotlin.psi.psiUtil.isAncestor
 import org.jetbrains.kotlin.psi.psiUtil.parentsWithSelf
 import java.util.*
@@ -43,13 +46,37 @@ interface PostProcessor {
     val phasesCount: Int
 
     fun doAdditionalProcessing(
-        file: KtFile,
+        target: JKPostProcessingTarget,
         converterContext: ConverterContext?,
-        rangeMarker: RangeMarker?,
         onPhaseChanged: ((Int, String) -> Unit)?
     )
 }
 
+sealed class JKPostProcessingTarget
+
+data class JKPieceOfCodePostProcessingTarget(
+    val file: KtFile,
+    val rangeMarker: RangeMarker
+) : JKPostProcessingTarget()
+
+
+data class JKMultipleFilesPostProcessingTarget(
+    val files: List<KtFile>
+) : JKPostProcessingTarget()
+
+fun JKPostProcessingTarget.elements() = when (this) {
+    is JKPieceOfCodePostProcessingTarget -> runReadAction {
+        val range = rangeMarker.range ?: return@runReadAction emptyList()
+        file.elementsInRange(range)
+    }
+    is JKMultipleFilesPostProcessingTarget -> files
+}
+
+fun JKPostProcessingTarget.files() = when (this) {
+    is JKPieceOfCodePostProcessingTarget -> listOf(file)
+    is JKMultipleFilesPostProcessingTarget -> files
+}
+
 enum class ParseContext {
     TOP_LEVEL,
     CODE_BLOCK
@@ -270,7 +297,7 @@ interface WithProgressProcessor {
         processItem: (TInputItem) -> TOutputItem
     ): List<TOutputItem>
 
-    fun updateState(fileIndex: Int, phase: Int, description: String)
+    fun updateState(fileIndex: Int?, phase: Int, description: String)
     fun <T> process(action: () -> T): T
 }
 
@@ -318,7 +345,7 @@ class OldWithProgressProcessor(private val progress: ProgressIndicator?, private
         throw AbstractMethodError("Should not be called for old J2K")
     }
 
-    override fun updateState(fileIndex: Int, phase: Int, description: String) {
+    override fun updateState(fileIndex: Int?, phase: Int, description: String) {
         throw AbstractMethodError("Should not be called for old J2K")
     }
 }