IJPL-165058 WEB-70490 WEB-70574 Introduce SuspendingLookupElementRenderer API to avoid creation of tons of threads, if the renderer performs suspending or blocking requests

(cherry picked from commit d2177ec9d91a0e4d2c85c8b1e0c1f8a065393853)

IJ-CR-150700

GitOrigin-RevId: 113d82171da592604e4c7902691a107a1f4d9023

platform/analysis-api/api-dump-unreviewed.txt

@@ -914,6 +914,11 @@ com.intellij.codeInsight.lookup.LookupListener
 - lookupCanceled(com.intellij.codeInsight.lookup.LookupEvent):V
 - lookupShown(com.intellij.codeInsight.lookup.LookupEvent):V
 - uiRefreshed():V
+a:com.intellij.codeInsight.lookup.SuspendingLookupElementRenderer
+- com.intellij.codeInsight.lookup.LookupElementRenderer
+- <init>():V
+- f:renderElement(com.intellij.codeInsight.lookup.LookupElement,com.intellij.codeInsight.lookup.LookupElementPresentation):V
+- a:renderElementSuspending(com.intellij.codeInsight.lookup.LookupElement,com.intellij.codeInsight.lookup.LookupElementPresentation,kotlin.coroutines.Continuation):java.lang.Object
 a:com.intellij.codeInsight.lookup.TailTypeDecorator
 - com.intellij.codeInsight.lookup.LookupElementDecorator
 - <init>(com.intellij.codeInsight.lookup.LookupElement):V

platform/analysis-api/src/com/intellij/codeInsight/lookup/SuspendingLookupElementRenderer.kt

@@ -0,0 +1,16 @@
+// Copyright 2000-2024 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.codeInsight.lookup
+
+import com.intellij.openapi.progress.runBlockingCancellable
+
+abstract class SuspendingLookupElementRenderer<T : LookupElement> : LookupElementRenderer<T>() {
+  /**
+   * Render LookupElement in a coroutine. There is no guarantee that the element is valid.
+   * The method will usually be called without a read lock.
+   */
+  abstract suspend fun renderElementSuspending(element: T, presentation: LookupElementPresentation)
+
+  final override fun renderElement(element: T, presentation: LookupElementPresentation) {
+    runBlockingCancellable { renderElementSuspending(element, presentation) }
+  }
+}

platform/lang-impl/src/com/intellij/codeInsight/lookup/impl/AsyncRendering.kt

@@ -6,6 +6,7 @@ package com.intellij.codeInsight.lookup.impl
 import com.intellij.codeInsight.lookup.LookupElement
 import com.intellij.codeInsight.lookup.LookupElementPresentation
 import com.intellij.codeInsight.lookup.LookupElementRenderer
+import com.intellij.codeInsight.lookup.SuspendingLookupElementRenderer
 import com.intellij.openapi.application.readAction
 import com.intellij.openapi.util.Key
 import com.intellij.util.indexing.DumbModeAccessType
@@ -42,11 +43,14 @@ internal class AsyncRendering(private val lookup: LookupImpl) {
 
       val job = lookup.coroutineScope.launch(limitedDispatcher) {
         val job = coroutineContext.job
-        readAction {
-          if (element.isValid) {
-            renderInBackground(element, renderer)
+        if (renderer is SuspendingLookupElementRenderer<LookupElement>) {
+          renderInBackgroundSuspending(element, renderer)
+        } else
+          readAction {
+            if (element.isValid) {
+              renderInBackground(element, renderer)
+            }
           }
-        }
         synchronized(LAST_COMPUTATION) {
           element.replace(LAST_COMPUTATION, job, null)
         }
@@ -65,4 +69,15 @@ internal class AsyncRendering(private val lookup: LookupImpl) {
     rememberPresentation(element, presentation)
     lookup.cellRenderer.scheduleUpdateLookupWidthFromVisibleItems()
   }
+
+  private suspend fun renderInBackgroundSuspending(element: LookupElement, renderer: SuspendingLookupElementRenderer<LookupElement>) {
+    val presentation = LookupElementPresentation()
+    renderer.renderElementSuspending(element, presentation)
+
+    presentation.freeze()
+    rememberPresentation(element, presentation)
+    lookup.cellRenderer.scheduleUpdateLookupWidthFromVisibleItems()
+  }
+
+
 }