KT-32366: Use TextEditorWithPreview as editor for scratch files

- get rid of `ScratchFileHook` completely
- use `KtsScratchFileEditorProvider` to encapsulate details about scratch file presentation
- remove obsolete functions from `scratchUtils`

idea/idea-jvm/src/org/jetbrains/kotlin/idea/scratch/actions/ClearScratchAction.kt

@@ -21,8 +21,7 @@ import com.intellij.openapi.actionSystem.AnActionEvent
 import com.intellij.openapi.fileEditor.FileEditorManager
 import com.intellij.openapi.fileEditor.impl.text.TextEditorProvider
 import org.jetbrains.kotlin.idea.KotlinBundle
-import org.jetbrains.kotlin.idea.scratch.attachedOutputHandler
+import org.jetbrains.kotlin.idea.scratch.ui.findScratchFileEditorWithPreview
-import org.jetbrains.kotlin.idea.scratch.getScratchFile
 
 class ClearScratchAction : ScratchAction(
     KotlinBundle.message("scratch.clear.button"),
@@ -33,8 +32,7 @@ class ClearScratchAction : ScratchAction(
 
         val selectedEditor = FileEditorManager.getInstance(project).selectedTextEditor ?: return
         val textEditor = TextEditorProvider.getInstance().getTextEditor(selectedEditor)
-        val scratchFile = textEditor.getScratchFile() ?: return
 
-        textEditor.attachedOutputHandler?.clear(scratchFile)
+        textEditor.findScratchFileEditorWithPreview()?.clearOutputHandlers()
     }
 }

idea/idea-jvm/src/org/jetbrains/kotlin/idea/scratch/scratchUtils.kt

@@ -12,14 +12,9 @@ import com.intellij.openapi.fileEditor.FileEditorManager
 import com.intellij.openapi.fileEditor.TextEditor
 import com.intellij.openapi.fileEditor.impl.text.TextEditorProvider
 import com.intellij.openapi.project.Project
-import com.intellij.openapi.util.Disposer
-import com.intellij.openapi.util.Key
 import com.intellij.openapi.vfs.VirtualFile
-import org.jetbrains.annotations.TestOnly
 import org.jetbrains.kotlin.idea.actions.KOTLIN_WORKSHEET_EXTENSION
-import org.jetbrains.kotlin.idea.scratch.output.ScratchOutputHandler
+import org.jetbrains.kotlin.idea.scratch.ui.findScratchFileEditorWithPreview
-import org.jetbrains.kotlin.idea.scratch.ui.ScratchTopPanel
-import org.jetbrains.kotlin.psi.UserDataProperty
 
 internal val LOG = Logger.getInstance("#org.jetbrains.kotlin.idea.scratch")
 internal fun Logger.printDebugMessage(str: String) {
@@ -32,12 +27,6 @@ val VirtualFile.isKotlinWorksheet: Boolean
 val VirtualFile.isKotlinScratch: Boolean
     get() = ScratchFileService.getInstance().getRootType(this) is ScratchRootType
 
-fun getEditorWithoutScratchFile(fileManager: FileEditorManager, virtualFile: VirtualFile): TextEditor? {
-    val editor = fileManager.getSelectedEditor(virtualFile) as? TextEditor
-    if (editor?.getScratchFile() != null) return null
-    return editor
-}
-
 fun getScratchFileFromEditorSelectedForFile(fileManager: FileEditorManager, virtualFile: VirtualFile): ScratchFile? {
     val editor = fileManager.getSelectedEditor(virtualFile) as? TextEditor ?: return null
     return editor.getScratchFile()
@@ -49,22 +38,5 @@ fun getScratchFileFromSelectedEditor(project: Project): ScratchFile? {
 }
 
 fun TextEditor.getScratchFile(): ScratchFile? {
-    return scratchTopPanel?.scratchFile
+    return findScratchFileEditorWithPreview()?.scratchFile
 }
-
-fun TextEditor.addScratchPanel(panel: ScratchTopPanel) {
-    scratchTopPanel = panel
-    FileEditorManager.getInstance(panel.scratchFile.project).addTopComponent(this, panel.component)
-
-    Disposer.register(this, panel)
-}
-
-fun TextEditor.attachOutputHandler(handler: ScratchOutputHandler) {
-    outputHandler = handler
-}
-
-val TextEditor.attachedOutputHandler: ScratchOutputHandler? get() = outputHandler
-
-private var TextEditor.scratchTopPanel: ScratchTopPanel? by UserDataProperty<TextEditor, ScratchTopPanel>(Key.create("scratch.panel"))
-
-private var TextEditor.outputHandler: ScratchOutputHandler? by UserDataProperty<TextEditor, ScratchOutputHandler>(Key.create("scratch.output.handler"))

idea/idea-jvm/src/org/jetbrains/kotlin/idea/scratch/ui/KtScratchFileEditorProvider.kt

@@ -0,0 +1,140 @@
+/*
+ * Copyright 2010-2019 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.kotlin.idea.scratch.ui
+
+import com.intellij.codeInsight.daemon.DaemonCodeAnalyzer
+import com.intellij.openapi.Disposable
+import com.intellij.openapi.actionSystem.ActionToolbar
+import com.intellij.openapi.application.ApplicationManager
+import com.intellij.openapi.editor.Editor
+import com.intellij.openapi.editor.EditorFactory
+import com.intellij.openapi.fileEditor.FileEditor
+import com.intellij.openapi.fileEditor.FileEditorPolicy
+import com.intellij.openapi.fileEditor.FileEditorProvider
+import com.intellij.openapi.fileEditor.TextEditor
+import com.intellij.openapi.fileEditor.impl.text.TextEditorProvider
+import com.intellij.openapi.project.DumbAware
+import com.intellij.openapi.project.Project
+import com.intellij.openapi.util.Disposer
+import com.intellij.openapi.util.Key
+import com.intellij.openapi.vfs.VirtualFile
+import com.intellij.pom.Navigatable
+import com.intellij.psi.PsiManager
+import org.jetbrains.kotlin.idea.scratch.*
+import org.jetbrains.kotlin.idea.scratch.output.InlayScratchOutputHandler
+import org.jetbrains.kotlin.idea.scratch.output.ScratchOutputHandlerAdapter
+import org.jetbrains.kotlin.psi.UserDataProperty
+
+private const val KTS_SCRATCH_EDITOR_PROVIDER: String = "KtsScratchFileEditorProvider"
+
+class KtScratchFileEditorProvider : FileEditorProvider, DumbAware {
+    override fun getEditorTypeId(): String = KTS_SCRATCH_EDITOR_PROVIDER
+
+    override fun accept(project: Project, file: VirtualFile): Boolean {
+        if (!file.isValid) return false
+        if (!(file.isKotlinScratch || file.isKotlinWorksheet)) return false
+        val psiFile = PsiManager.getInstance(project).findFile(file) ?: return false
+        return ScratchFileLanguageProvider.get(psiFile.fileType) != null
+    }
+
+    override fun createEditor(project: Project, file: VirtualFile): FileEditor {
+        val scratchFile = createScratchFile(project, file) ?: return TextEditorProvider.getInstance().createEditor(project, file)
+
+        return KtScratchFileEditorWithPreview.create(scratchFile)
+    }
+
+    override fun getPolicy(): FileEditorPolicy = FileEditorPolicy.HIDE_DEFAULT_EDITOR
+}
+
+class KtScratchFileEditorWithPreview private constructor(
+    val scratchFile: ScratchFile,
+    editor: TextEditor,
+    preview: TextEditor
+) : TextEditorWithPreview(editor, preview), TextEditor {
+
+    private val inlayOutputHandler = InlayScratchOutputHandler(editor)
+    private val scratchTopPanel = ScratchTopPanel(scratchFile)
+
+    init {
+        editor.parentScratchEditorWithPreview = this
+
+        scratchFile.compilingScratchExecutor?.addOutputHandler(inlayOutputHandler)
+        scratchFile.replScratchExecutor?.addOutputHandler(inlayOutputHandler)
+
+        ScratchFileAutoRunner.addListener(scratchFile.project, editor)
+    }
+
+    override fun dispose() {
+        scratchFile.replScratchExecutor?.stop()
+        scratchFile.compilingScratchExecutor?.stop()
+        super.dispose()
+    }
+
+    override fun navigateTo(navigatable: Navigatable) {
+        myEditor.navigateTo(navigatable)
+    }
+
+    override fun canNavigateTo(navigatable: Navigatable): Boolean {
+        return myEditor.canNavigateTo(navigatable)
+    }
+
+    override fun getEditor(): Editor {
+        return myEditor.editor
+    }
+
+    override fun createToolbar(): ActionToolbar? {
+        return scratchTopPanel.actionsToolbar
+    }
+
+    fun clearOutputHandlers() {
+        inlayOutputHandler.clear(scratchFile)
+    }
+
+    companion object {
+        fun create(scratchFile: ScratchFile): KtScratchFileEditorWithPreview {
+            val textEditorProvider = TextEditorProvider.getInstance()
+
+            val mainEditor = textEditorProvider.createEditor(scratchFile.project, scratchFile.file) as TextEditor
+            val editorFactory = EditorFactory.getInstance()
+
+            val viewer = editorFactory.createViewer(editorFactory.createDocument(""))
+            Disposer.register(mainEditor, Disposable { editorFactory.releaseEditor(viewer) })
+
+            val previewEditor = textEditorProvider.getTextEditor(viewer)
+
+            return KtScratchFileEditorWithPreview(scratchFile, mainEditor, previewEditor)
+        }
+    }
+}
+
+fun TextEditor.findScratchFileEditorWithPreview(): KtScratchFileEditorWithPreview? =
+    if (this is KtScratchFileEditorWithPreview) this else parentScratchEditorWithPreview
+
+private var TextEditor.parentScratchEditorWithPreview: KtScratchFileEditorWithPreview?
+        by UserDataProperty(Key.create("parent.preview.editor"))
+
+fun createScratchFile(project: Project, file: VirtualFile): ScratchFile? {
+    val psiFile = PsiManager.getInstance(project).findFile(file) ?: return null
+    val scratchFile = ScratchFileLanguageProvider.get(psiFile.language)?.newScratchFile(project, file) ?: return null
+    setupCodeAnalyzerRestarterOutputHandler(project, scratchFile)
+
+    return scratchFile
+}
+
+private fun setupCodeAnalyzerRestarterOutputHandler(project: Project, scratchFile: ScratchFile) {
+    scratchFile.replScratchExecutor?.addOutputHandler(object : ScratchOutputHandlerAdapter() {
+        override fun onFinish(file: ScratchFile) {
+            ApplicationManager.getApplication().invokeLater {
+                if (!file.project.isDisposed) {
+                    val scratch = file.getPsiFile()
+                    if (scratch?.isValid == true) {
+                        DaemonCodeAnalyzer.getInstance(project).restart(scratch)
+                    }
+                }
+            }
+        }
+    })
+}

idea/idea-jvm/src/org/jetbrains/kotlin/idea/scratch/ui/ScratchFileHook.kt

@@ -1,87 +0,0 @@
-/*
- * 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.scratch.ui
-
-import com.intellij.codeInsight.daemon.DaemonCodeAnalyzer
-import com.intellij.openapi.application.ApplicationManager
-import com.intellij.openapi.components.ProjectComponent
-import com.intellij.openapi.fileEditor.FileEditorManager
-import com.intellij.openapi.fileEditor.FileEditorManagerListener
-import com.intellij.openapi.project.Project
-import com.intellij.openapi.vfs.VirtualFile
-import com.intellij.psi.PsiManager
-import org.jetbrains.kotlin.idea.scratch.*
-import org.jetbrains.kotlin.idea.scratch.output.InlayScratchOutputHandler
-import org.jetbrains.kotlin.idea.scratch.output.ScratchOutputHandlerAdapter
-
-class ScratchFileHook(val project: Project) : ProjectComponent {
-
-    override fun projectOpened() {
-        project.messageBus.connect(project).subscribe(FileEditorManagerListener.FILE_EDITOR_MANAGER, ScratchEditorListener())
-    }
-
-    private inner class ScratchEditorListener : FileEditorManagerListener {
-        override fun fileOpened(source: FileEditorManager, file: VirtualFile) {
-            if (!isPluggable(file)) return
-
-            val editor = getEditorWithoutScratchFile(source, file) ?: return
-
-            val scratchFile = createScratchFile(project, file) ?: return
-
-            val inlayOutputHandler = InlayScratchOutputHandler(editor)
-            scratchFile.compilingScratchExecutor?.addOutputHandler(inlayOutputHandler)
-            scratchFile.replScratchExecutor?.addOutputHandler(inlayOutputHandler)
-            editor.attachOutputHandler(inlayOutputHandler)
-
-            editor.addScratchPanel(ScratchTopPanel(scratchFile))
-
-            ScratchFileAutoRunner.addListener(project, editor)
-        }
-
-        override fun fileClosed(source: FileEditorManager, file: VirtualFile) {}
-    }
-
-    private fun isPluggable(file: VirtualFile): Boolean {
-        if (!file.isValid) return false
-        if (!(file.isKotlinScratch || file.isKotlinWorksheet)) return false
-        val psiFile = PsiManager.getInstance(project).findFile(file) ?: return false
-        return ScratchFileLanguageProvider.get(psiFile.fileType) != null
-    }
-}
-
-private fun createScratchFile(project: Project, file: VirtualFile): ScratchFile? {
-    val psiFile = PsiManager.getInstance(project).findFile(file) ?: return null
-    val scratchFile = ScratchFileLanguageProvider.get(psiFile.language)?.newScratchFile(project, file) ?: return null
-    setupReplRestartingOutputHandler(project, scratchFile)
-
-    return scratchFile
-}
-
-private fun setupReplRestartingOutputHandler(project: Project, scratchFile: ScratchFile) {
-    scratchFile.replScratchExecutor?.addOutputHandler(object : ScratchOutputHandlerAdapter() {
-        override fun onFinish(file: ScratchFile) {
-            ApplicationManager.getApplication().invokeLater {
-                if (!file.project.isDisposed) {
-                    val scratch = file.getPsiFile()
-                    if (scratch?.isValid == true) {
-                        DaemonCodeAnalyzer.getInstance(project).restart(scratch)
-                    }
-                }
-            }
-        }
-    })
-}

idea/idea-jvm/src/org/jetbrains/kotlin/idea/scratch/ui/ScratchTopPanel.kt

@@ -29,17 +29,11 @@ import org.jetbrains.kotlin.idea.scratch.actions.StopScratchAction
 import org.jetbrains.kotlin.idea.scratch.output.ScratchOutputHandlerAdapter
 import javax.swing.JComponent
 
-class ScratchTopPanel(val scratchFile: ScratchFile) : Disposable {
+class ScratchTopPanel(val scratchFile: ScratchFile) {
-    override fun dispose() {
-        scratchFile.replScratchExecutor?.stop()
-        scratchFile.compilingScratchExecutor?.stop()
-    }
-
     private val moduleChooserAction: ModulesComboBoxAction = ModulesComboBoxAction(scratchFile)
-    private val actionsToolbar: ActionToolbar
+    val actionsToolbar: ActionToolbar
 
     init {
-        scratchFile.addModuleListener { _, _ -> updateToolbar() }
         setupTopPanelUpdateHandlers()
 
         val toolbarGroup = DefaultActionGroup().apply {
@@ -59,9 +53,9 @@ class ScratchTopPanel(val scratchFile: ScratchFile) : Disposable {
         actionsToolbar = ActionManager.getInstance().createActionToolbar(ActionPlaces.EDITOR_TOOLBAR, toolbarGroup, true)
     }
 
-    val component: JComponent = actionsToolbar.component
-
     private fun setupTopPanelUpdateHandlers() {
+        scratchFile.addModuleListener { _, _ -> updateToolbar() }
+
         val toolbarHandler = createUpdateToolbarHandler()
         scratchFile.replScratchExecutor?.addOutputHandler(toolbarHandler)
         scratchFile.compilingScratchExecutor?.addOutputHandler(toolbarHandler)

idea/resources/META-INF/extensions/ide.xml

@@ -100,6 +100,7 @@
                      description="Add all transitive dependencies on MPP modules when Android project is imported"
                      defaultValue="true"
                      restartRequired="false"/>
+        <fileEditorProvider implementation="org.jetbrains.kotlin.idea.scratch.ui.KtScratchFileEditorProvider"/>
 
     </extensions>
 </idea-plugin>

idea/resources/META-INF/extensions/ide.xml.183

@@ -104,6 +104,7 @@
                      description="Add all transitive dependencies on MPP modules when Android project is imported"
                      defaultValue="true"
                      restartRequired="false"/>
+        <fileEditorProvider implementation="org.jetbrains.kotlin.idea.scratch.ui.KtScratchFileEditorProvider"/>
 
     </extensions>
 </idea-plugin>

idea/resources/META-INF/extensions/ide.xml.as33

@@ -96,6 +96,7 @@
                      description="Add all transitive dependencies on MPP modules when Android project is imported"
                      defaultValue="true"
                      restartRequired="false"/>
+        <fileEditorProvider implementation="org.jetbrains.kotlin.idea.scratch.ui.KtScratchFileEditorProvider"/>
 
     </extensions>
 </idea-plugin>

idea/resources/META-INF/extensions/ide.xml.as34

@@ -95,6 +95,7 @@
                      description="Add all transitive dependencies on MPP modules when Android project is imported"
                      defaultValue="true"
                      restartRequired="false"/>
+            <fileEditorProvider implementation="org.jetbrains.kotlin.idea.scratch.ui.KtScratchFileEditorProvider"/>
 
     </extensions>
 </idea-plugin>

idea/resources/META-INF/jvm.xml

@@ -17,9 +17,6 @@
         <component>
             <implementation-class>org.jetbrains.kotlin.idea.configuration.ui.KotlinConfigurationCheckerComponent</implementation-class>
         </component>
-        <component>
-            <implementation-class>org.jetbrains.kotlin.idea.scratch.ui.ScratchFileHook</implementation-class>
-        </component>
         <component>
             <implementation-class>org.jetbrains.kotlin.idea.scratch.ScratchFileModuleInfoProvider</implementation-class>
         </component>

idea/resources/META-INF/jvm.xml.182

@@ -17,9 +17,6 @@
         <component>
             <implementation-class>org.jetbrains.kotlin.idea.configuration.ui.KotlinConfigurationCheckerComponent</implementation-class>
         </component>
-        <component>
-            <implementation-class>org.jetbrains.kotlin.idea.scratch.ui.ScratchFileHook</implementation-class>
-        </component>
         <component>
             <implementation-class>org.jetbrains.kotlin.idea.scratch.ScratchFileModuleInfoProvider</implementation-class>
         </component>

idea/resources/META-INF/jvm.xml.183

@@ -17,9 +17,6 @@
         <component>
             <implementation-class>org.jetbrains.kotlin.idea.configuration.ui.KotlinConfigurationCheckerComponent</implementation-class>
         </component>
-        <component>
-            <implementation-class>org.jetbrains.kotlin.idea.scratch.ui.ScratchFileHook</implementation-class>
-        </component>
         <component>
             <implementation-class>org.jetbrains.kotlin.idea.scratch.ScratchFileModuleInfoProvider</implementation-class>
         </component>