Use background task for Kotlin decompiler (KT-23981)

#KT-23981 Fixed

idea/idea-jvm/src/org/jetbrains/kotlin/idea/internal/KotlinDecompilerServiceImpl.kt

@@ -29,6 +29,7 @@ import org.jetbrains.kotlin.config.CompilerConfiguration
 import org.jetbrains.kotlin.config.languageVersionSettings
 import org.jetbrains.kotlin.idea.actions.canBeDecompiledToJava
 import org.jetbrains.kotlin.idea.project.languageVersionSettings
+import org.jetbrains.kotlin.idea.util.application.runReadAction
 import org.jetbrains.kotlin.psi.KtFile
 import java.io.File
 import java.util.jar.Manifest
@@ -36,11 +37,14 @@ import java.util.jar.Manifest
 class KotlinDecompilerServiceImpl : KotlinDecompilerService {
     override fun decompile(file: KtFile): String? {
         try {
-            val bytecodeMap = when {
+            val bytecodeMap: Map<File, () -> ByteArray> = runReadAction {
-                file.canBeDecompiledToJava() -> bytecodeMapForExistingClassfile(file.virtualFile)
+                when {
-                !file.isCompiled -> bytecodeMapForSourceFile(file)
+                    file.canBeDecompiledToJava() -> bytecodeMapForExistingClassfile(file.virtualFile)
-                else -> return null
+                    !file.isCompiled -> bytecodeMapForSourceFile(file)
-            }
+                    else -> null
+                }
+            } ?: return null
+
             val resultSaver = KotlinResultSaver()
             val options = hashMapOf<String, Any>(
                 IFernflowerPreferences.REMOVE_BRIDGE to "0"

idea/src/org/jetbrains/kotlin/idea/internal/KotlinDecompilerAdapter.kt

@@ -5,7 +5,11 @@
 
 package org.jetbrains.kotlin.idea.internal
 
+import com.intellij.openapi.application.ApplicationManager
 import com.intellij.openapi.fileEditor.OpenFileDescriptor
+import com.intellij.openapi.progress.ProgressIndicator
+import com.intellij.openapi.progress.ProgressManager
+import com.intellij.openapi.progress.Task
 import com.intellij.openapi.ui.Messages
 import com.intellij.openapi.util.io.FileUtil
 import com.intellij.openapi.vfs.VfsUtil
@@ -16,25 +20,38 @@ import org.jetbrains.kotlin.idea.util.application.runWriteAction
 import org.jetbrains.kotlin.psi.KtFile
 
 fun showDecompiledCode(sourceFile: KtFile) {
-    val decompilerService = KotlinDecompilerService.getInstance() ?: return
+    ProgressManager.getInstance().run(KotlinBytecodeDecompilerTask(sourceFile))
-    val decompiledCode = try {
+}
-        decompilerService.decompile(sourceFile)
-    } catch (e: DecompileFailedException) {
-        null
-    }
 
-    if (decompiledCode == null) {
+class KotlinBytecodeDecompilerTask(val file: KtFile) : Task.Backgroundable(file.project, "Decompile kotlin bytecode") {
-        Messages.showErrorDialog("Cannot decompile ${sourceFile.name}", "Decompiler error")
+    override fun run(indicator: ProgressIndicator) {
-        return
+        val decompilerService = KotlinDecompilerService.getInstance() ?: return
-    }
 
-    runWriteAction {
+        indicator.text = "Decompiling ${file.name}"
-        val root = getOrCreateDummyRoot()
-        val decompiledFileName = FileUtil.getNameWithoutExtension(sourceFile.name) + ".decompiled.java"
-        val result = DummyFileSystem.getInstance().createChildFile(null, root, decompiledFileName)
-        VfsUtil.saveText(result, decompiledCode)
 
-        OpenFileDescriptor(sourceFile.project, result).navigate(true)
+        val decompiledText = try {
+            decompilerService.decompile(file)
+        } catch (e: DecompileFailedException) {
+            null
+        }
+
+        ApplicationManager.getApplication().invokeLater {
+            runWriteAction {
+                if (!file.isValid || file.project.isDisposed) return@runWriteAction
+
+                if (decompiledText == null) {
+                    Messages.showErrorDialog("Cannot decompile ${file.name}", "Decompiler error")
+                    return@runWriteAction
+                }
+
+                val root = getOrCreateDummyRoot()
+                val decompiledFileName = FileUtil.getNameWithoutExtension(file.name) + ".decompiled.java"
+                val result = DummyFileSystem.getInstance().createChildFile(null, root, decompiledFileName)
+                VfsUtil.saveText(result, decompiledText)
+
+                OpenFileDescriptor(file.project, result).navigate(true)
+            }
+        }
     }
 }