From b56e959d600c7f8ea6a9e785b76f023ed027a388 Mon Sep 17 00:00:00 2001
From: Lorn Potter <lorn.potter@gmail.com>
Date: Mon, 17 Jun 2024 15:38:09 +1000
Subject: [PATCH] wasm: fix wasm sockets when data buffer is less than 3696
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The socket message comes in too early so add an additional
postEvent when registering the socket notifier.

Fixes: QTBUG-125874
Change-Id: Ie951b7a1b858d12927478e071157780ac4fc320b
Reviewed-by: Lorn Potter <lorn.potter@qt.io>
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
(cherry picked from commit 9b01f1bdb7e4107de3f898446fa087efa81e029e)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---
 src/corelib/kernel/qeventdispatcher_wasm.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/corelib/kernel/qeventdispatcher_wasm.cpp b/src/corelib/kernel/qeventdispatcher_wasm.cpp
index e1ec858ef04..d9f234d4192 100644
--- a/src/corelib/kernel/qeventdispatcher_wasm.cpp
+++ b/src/corelib/kernel/qeventdispatcher_wasm.cpp
@@ -8,6 +8,7 @@
 #include <QtCore/qthread.h>
 #include <QtCore/qsocketnotifier.h>
 #include <QtCore/private/qstdweb_p.h>
+#include <sys/ioctl.h>
 
 #include "emscripten.h"
 #include <emscripten/html5.h>
@@ -337,6 +338,14 @@ void QEventDispatcherWasm::registerSocketNotifier(QSocketNotifier *notifier)
     g_socketNotifiers.insert({notifier->socket(), notifier});
     if (wasEmpty)
         runOnMainThread([] { setEmscriptenSocketCallbacks(); });
+
+    int count;
+    ioctl(notifier->socket(), FIONREAD, &count);
+
+    // message may have arrived already
+    if (count > 0 && notifier->type() == QSocketNotifier::Read) {
+        QCoreApplication::postEvent(notifier, new QEvent(QEvent::SockAct));
+    }
 }
 
 void QEventDispatcherWasm::unregisterSocketNotifier(QSocketNotifier *notifier)