From f2b9ec9f8a1f1a4cc503fb4fddf97d7c27bdee79 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sat, 25 Sep 2021 19:32:14 +0200
Subject: [PATCH] LibCore: Add Core::EventLoop::spin_until(Function<bool()>)

This function spins the event loop until a goal condition is met.
---
 Userland/Libraries/LibCore/EventLoop.cpp | 7 +++++++
 Userland/Libraries/LibCore/EventLoop.h   | 2 ++
 2 files changed, 9 insertions(+)

diff --git a/Userland/Libraries/LibCore/EventLoop.cpp b/Userland/Libraries/LibCore/EventLoop.cpp
index 081c34acdb..fafd7aaae3 100644
--- a/Userland/Libraries/LibCore/EventLoop.cpp
+++ b/Userland/Libraries/LibCore/EventLoop.cpp
@@ -366,6 +366,13 @@ int EventLoop::exec()
     VERIFY_NOT_REACHED();
 }
 
+void EventLoop::spin_until(Function<bool()> goal_condition)
+{
+    EventLoopPusher pusher(*this);
+    while (!goal_condition())
+        pump();
+}
+
 void EventLoop::pump(WaitMode mode)
 {
     wait_for_event(mode);
diff --git a/Userland/Libraries/LibCore/EventLoop.h b/Userland/Libraries/LibCore/EventLoop.h
index 047de38234..9b1a660e80 100644
--- a/Userland/Libraries/LibCore/EventLoop.h
+++ b/Userland/Libraries/LibCore/EventLoop.h
@@ -44,6 +44,8 @@ public:
     // this should really only be used for integrating with other event loops
     void pump(WaitMode = WaitMode::WaitForEvents);
 
+    void spin_until(Function<bool()>);
+
     void post_event(Object& receiver, NonnullOwnPtr<Event>&&);
 
     static EventLoop& main();