From e5f6093e082f46ccb98bf8df8c236bfbfdcaa14a Mon Sep 17 00:00:00 2001
From: peter <peter@jetbrains.com>
Date: Thu, 26 Apr 2018 10:16:22 +0200
Subject: [PATCH] return Promise from AppUIExecutor

---
 .../openapi/application/AppUIExecutor.java    | 14 +++++++
 .../application/impl/AppUIExecutorImpl.java   | 42 +++++++++++--------
 2 files changed, 39 insertions(+), 17 deletions(-)

diff --git a/platform/core-api/src/com/intellij/openapi/application/AppUIExecutor.java b/platform/core-api/src/com/intellij/openapi/application/AppUIExecutor.java
index 63a380be5a91..b7ef24b8791c 100644
--- a/platform/core-api/src/com/intellij/openapi/application/AppUIExecutor.java
+++ b/platform/core-api/src/com/intellij/openapi/application/AppUIExecutor.java
@@ -6,7 +6,9 @@ import com.intellij.openapi.project.Project;
 import com.intellij.psi.PsiDocumentManager;
 import org.jetbrains.annotations.Contract;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.concurrency.CancellablePromise;
 
+import java.util.concurrent.Callable;
 import java.util.concurrent.Executor;
 
 /**
@@ -73,5 +75,17 @@ public interface AppUIExecutor extends Executor {
   @NotNull
   @Contract(pure=true)
   AppUIExecutor expireWith(@NotNull Disposable parentDisposable);
+
+  /**
+   * Schedule the given task's execution and return a Promise that allows to get the result when the task is complete,
+   * or cancel the task if it's no longer needed.
+   */
+  <T> CancellablePromise<T> submit(Callable<T> task);
+
+  /**
+   * Schedule the given task's execution and return a Promise that allows to check if the task is complete,
+   * or cancel the task if it's no longer needed.
+   */
+  CancellablePromise<?> submit(Runnable task);
   
 }
diff --git a/platform/platform-impl/src/com/intellij/openapi/application/impl/AppUIExecutorImpl.java b/platform/platform-impl/src/com/intellij/openapi/application/impl/AppUIExecutorImpl.java
index 248247e724d8..8cdc0f65c7ac 100644
--- a/platform/platform-impl/src/com/intellij/openapi/application/impl/AppUIExecutorImpl.java
+++ b/platform/platform-impl/src/com/intellij/openapi/application/impl/AppUIExecutorImpl.java
@@ -12,12 +12,14 @@ import com.intellij.psi.PsiDocumentManager;
 import com.intellij.util.ArrayUtil;
 import com.intellij.util.containers.ContainerUtil;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.concurrency.AsyncPromise;
+import org.jetbrains.concurrency.CancellablePromise;
 
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Set;
-import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Callable;
 
 /**
  * @author peter
@@ -163,31 +165,37 @@ class AppUIExecutorImpl implements AppUIExecutor {
   }
 
   @Override
-  public void execute(@NotNull Runnable runnable) {
-    CompletableFuture<Void> future = new CompletableFuture<>();
+  public CancellablePromise<?> submit(Runnable task) {
+    return submit(() -> { task.run(); return null; });
+  }
+
+  @Override
+  public void execute(@NotNull Runnable command) {
+    submit(command);
+  }
+
+  @Override
+  public <T> CancellablePromise<T> submit(Callable<T> task) {
+    AsyncPromise<T> promise = new AsyncPromise<>();
 
     if (!myDisposables.isEmpty()) {
       List<Disposable> children = new ArrayList<>();
       for (Disposable parent : myDisposables) {
-        Disposable child = new Disposable() {
-          @Override
-          public void dispose() {
-            future.cancel(false);
-          }
-        };
+        Disposable child = promise::cancel;
         children.add(child);
         Disposer.register(parent, child);
       }
-      future.whenComplete((v, t) -> children.forEach(Disposer::dispose));
+      promise.onProcessed(__ -> children.forEach(Disposer::dispose));
     }
 
-    checkConstraints(runnable, future, new ArrayList<>());
+    checkConstraints(task, promise, new ArrayList<>());
+    return promise;
   }
 
-  private void checkConstraints(@NotNull Runnable runnable, CompletableFuture<Void> future, List<ConstrainedExecutor> log) {
+  private <T> void checkConstraints(@NotNull Callable<T> task, AsyncPromise<T> future, List<ConstrainedExecutor> log) {
     Application app = ApplicationManager.getApplication();
     if (!app.isDispatchThread()) {
-      app.invokeLater(() -> checkConstraints(runnable, future, log), myModality);
+      app.invokeLater(() -> checkConstraints(task, future, log), myModality);
       return;
     }
     
@@ -199,17 +207,17 @@ class AppUIExecutorImpl implements AppUIExecutor {
         if (log.size() > 1000) {
           LOG.error("Too many reschedule requests, probably constraints can't be satisfied all together: " + log.subList(100, 120));
         }
-        constraint.rescheduleInCorrectContext(() -> checkConstraints(runnable, future, log));
+        constraint.rescheduleInCorrectContext(() -> checkConstraints(task, future, log));
         return;
       }
     }
 
     try {
-      runnable.run();
-      future.complete(null);
+      T result = task.call();
+      future.setResult(result);
     }
     catch (Throwable e) {
-      future.completeExceptionally(e);
+      future.setError(e);
     }
   }