From be90db7fca7c590012f96c073197afb10da94848 Mon Sep 17 00:00:00 2001
From: Ilya Kirillov <ilya.kirillov@jetbrains.com>
Date: Tue, 18 Dec 2018 14:37:57 +0300
Subject: [PATCH] New J2K: Add ParameterModificationInMethodCallsConversion

---
 ...eterModificationInMethodCallsConversion.kt | 33 ++++++++++++++++
 .../org/jetbrains/kotlin/j2k/expressions.kt   | 39 +++++++++++++++++++
 2 files changed, 72 insertions(+)
 create mode 100644 j2k/newSrc/org/jetbrains/kotlin/j2k/conversions/ParameterModificationInMethodCallsConversion.kt

diff --git a/j2k/newSrc/org/jetbrains/kotlin/j2k/conversions/ParameterModificationInMethodCallsConversion.kt b/j2k/newSrc/org/jetbrains/kotlin/j2k/conversions/ParameterModificationInMethodCallsConversion.kt
new file mode 100644
index 00000000000..08fbb33b055
--- /dev/null
+++ b/j2k/newSrc/org/jetbrains/kotlin/j2k/conversions/ParameterModificationInMethodCallsConversion.kt
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. 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.j2k.conversions
+
+import org.jetbrains.kotlin.j2k.ConversionContext
+import org.jetbrains.kotlin.j2k.asAssignmentFromTarget
+import org.jetbrains.kotlin.j2k.findUsages
+import org.jetbrains.kotlin.j2k.hasWritableUsages
+import org.jetbrains.kotlin.j2k.tree.*
+import org.jetbrains.kotlin.j2k.tree.impl.*
+
+
+class ParameterModificationInMethodCallsConversion(private val context: ConversionContext) : RecursiveApplicableConversionBase() {
+    override fun applyToElement(element: JKTreeElement): JKTreeElement {
+        if (element !is JKMethod) return recurse(element)
+        val newVariables =
+            element.parameters.mapNotNull { parameter ->
+                if (parameter.hasWritableUsages(element.block, context)) {
+                    JKLocalVariableImpl(
+                        JKTypeElementImpl(parameter.type.type),
+                        JKNameIdentifierImpl(parameter.name.value),
+                        JKFieldAccessExpressionImpl(context.symbolProvider.provideUniverseSymbol(parameter)),
+                        Mutability.MUTABLE
+                    )
+                } else null
+            }
+        element.block.statements = listOf(JKDeclarationStatementImpl(newVariables)) + element.block.statements
+        return recurse(element)
+    }
+}
\ No newline at end of file
diff --git a/j2k/newSrc/org/jetbrains/kotlin/j2k/expressions.kt b/j2k/newSrc/org/jetbrains/kotlin/j2k/expressions.kt
index f157d86dc53..fcf5709202d 100644
--- a/j2k/newSrc/org/jetbrains/kotlin/j2k/expressions.kt
+++ b/j2k/newSrc/org/jetbrains/kotlin/j2k/expressions.kt
@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.j2k
 import com.intellij.psi.PsiElement
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.j2k.ast.Nullability
+import org.jetbrains.kotlin.j2k.conversions.RecursiveApplicableConversionBase
 import org.jetbrains.kotlin.j2k.conversions.multiResolveFqName
 import org.jetbrains.kotlin.j2k.conversions.resolveFqName
 import org.jetbrains.kotlin.j2k.tree.*
@@ -220,3 +221,41 @@ fun throwAnnotation(throws: List<JKType>, symbolProvider: JKSymbolProvider) =
             }
         )
     )
+
+fun JKVariable.findUsages(scope: JKTreeElement, context: ConversionContext): List<JKFieldAccessExpression> {
+    val symbol = context.symbolProvider.provideUniverseSymbol(this)
+    val usages = mutableListOf<JKFieldAccessExpression>()
+    val searcher = object : RecursiveApplicableConversionBase() {
+        override fun applyToElement(element: JKTreeElement): JKTreeElement {
+            if (element is JKExpression) {
+                element.unboxFieldReference()?.also {
+                    if (it.identifier == symbol) {
+                        usages += it
+                    }
+                }
+            }
+            return recurse(element)
+        }
+    }
+    searcher.runConversion(scope, context)
+    return usages
+}
+
+fun JKExpression.unboxFieldReference(): JKFieldAccessExpression? = when {
+    this is JKFieldAccessExpression -> this
+    this is JKQualifiedExpression && receiver is JKThisExpression -> selector as? JKFieldAccessExpression
+    else -> null
+}
+
+fun JKFieldAccessExpression.asAssignmentFromTarget(): JKKtAssignmentStatement? =
+    (parent as? JKKtAssignmentStatement)
+        ?.takeIf { it.field == this }
+
+fun JKFieldAccessExpression.isInDecrementOrIncrement(): Boolean =
+    (parent as? JKUnaryExpression)?.operator?.token?.text in listOf("++", "--")
+
+fun JKVariable.hasWritableUsages(scope: JKTreeElement, context: ConversionContext): Boolean =
+    findUsages(scope, context).any {
+        it.asAssignmentFromTarget() != null
+                || it.isInDecrementOrIncrement()
+    }
\ No newline at end of file