KT-18051: Allow copy-pasting from IDEA java to kotlin conversion

#KT-18051 fixed

idea/src/org/jetbrains/kotlin/idea/conversion/copy/ConvertTextJavaCopyPasteProcessor.kt

@@ -65,16 +65,17 @@ class ConvertTextJavaCopyPasteProcessor : CopyPastePostProcessor<TextBlockTransf
     }
 
     override fun collectTransferableData(file: PsiFile, editor: Editor, startOffsets: IntArray, endOffsets: IntArray): List<TextBlockTransferableData> {
+        if (file is KtFile) return listOf(CopiedKotlinCode(file.text, startOffsets, endOffsets))
         return emptyList()
     }
 
     override fun extractTransferableData(content: Transferable): List<TextBlockTransferableData> {
         try {
             if (content.isDataFlavorSupported(DataFlavor.stringFlavor)) {
-                // check if it's copied from within IDEA
-                if (!Companion.convertOnCopyInsideIDE && content.transferDataFlavors.any { TextBlockTransferableData::class.java.isAssignableFrom(it.representationClass) }) {
-                    return emptyList()
-                }
+
+                if (content.isDataFlavorSupported(CopiedKotlinCode.DATA_FLAVOR) ||
+                    /* Handled by ConvertJavaCopyPasteProcessor */
+                    content.isDataFlavorSupported(CopiedJavaCode.DATA_FLAVOR)) return emptyList()
 
                 val text = content.getTransferData(DataFlavor.stringFlavor) as String
                 return listOf(MyTransferableData(text))
@@ -284,6 +285,5 @@ class ConvertTextJavaCopyPasteProcessor : CopyPastePostProcessor<TextBlockTransf
 
     companion object {
         @TestOnly var conversionPerformed: Boolean = false
-        @TestOnly var convertOnCopyInsideIDE: Boolean = false
     }
 }

idea/src/org/jetbrains/kotlin/idea/conversion/copy/CopiedKotlinCode.kt

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.idea.conversion.copy
+
+import com.intellij.codeInsight.editorActions.TextBlockTransferableData
+
+import java.awt.datatransfer.DataFlavor
+
+class CopiedKotlinCode(val fileText: String, val startOffsets: IntArray, val endOffsets: IntArray) : TextBlockTransferableData {
+
+    override fun getFlavor() = DATA_FLAVOR
+    override fun getOffsetCount() = 0
+
+    override fun getOffsets(offsets: IntArray?, index: Int) = index
+    override fun setOffsets(offsets: IntArray?, index: Int) = index
+
+    companion object {
+        val DATA_FLAVOR: DataFlavor = DataFlavor(CopiedKotlinCode::class.java, "Copied kotlin code")
+    }
+}

idea/tests/org/jetbrains/kotlin/idea/conversion/copy/AbstractTextJavaToKotlinCopyPasteConversionTest.kt

@@ -63,14 +63,8 @@ abstract class AbstractTextJavaToKotlinCopyPasteConversionTest : AbstractCopyPas
         configureTargetFile(testName + ".to.kt")
 
         ConvertTextJavaCopyPasteProcessor.conversionPerformed = false
-        ConvertTextJavaCopyPasteProcessor.convertOnCopyInsideIDE = true
 
-        try {
-            myFixture.performEditorAction(IdeActions.ACTION_PASTE)
-        }
-        finally {
-            ConvertTextJavaCopyPasteProcessor.convertOnCopyInsideIDE = false
-        }
+        myFixture.performEditorAction(IdeActions.ACTION_PASTE)
 
         kotlin.test.assertEquals(noConversionExpected, !ConvertTextJavaCopyPasteProcessor.conversionPerformed,
                                  if (noConversionExpected) "Conversion to Kotlin should not be suggested" else "No conversion to Kotlin suggested")