From 541715008bea659104a1705caa69a7bfd3f36637 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Wed, 22 Jan 2020 18:22:25 -0800
Subject: [PATCH] Qt: Fix race condition with proxied video events

---
 CHANGES                        |  1 +
 src/feature/thread-proxy.c     |  1 +
 src/platform/qt/VideoProxy.cpp | 15 ++++++++++++++-
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/CHANGES b/CHANGES
index f78fd6a24..6c06fad42 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,7 @@
 0.9.0: (Future)
 Other fixes:
  - Qt: Only dynamically reset video scale if a game is running
+ - Qt: Fix race condition with proxied video events
 
 0.8.0: (2020-01-21)
 Features:
diff --git a/src/feature/thread-proxy.c b/src/feature/thread-proxy.c
index 29a3161e7..ba1785c46 100644
--- a/src/feature/thread-proxy.c
+++ b/src/feature/thread-proxy.c
@@ -138,6 +138,7 @@ static void _postEvent(struct mVideoLogger* logger, enum mVideoLoggerEvent event
 	MutexLock(&proxyRenderer->mutex);
 	proxyRenderer->event = event;
 	ConditionWake(&proxyRenderer->toThreadCond);
+	ConditionWait(&proxyRenderer->fromThreadCond, &proxyRenderer->mutex);
 	MutexUnlock(&proxyRenderer->mutex);
 }
 
diff --git a/src/platform/qt/VideoProxy.cpp b/src/platform/qt/VideoProxy.cpp
index 431de4d26..8a89ea533 100644
--- a/src/platform/qt/VideoProxy.cpp
+++ b/src/platform/qt/VideoProxy.cpp
@@ -7,6 +7,8 @@
 
 #include "CoreController.h"
 
+#include <QThread>
+
 using namespace QGBA;
 
 VideoProxy::VideoProxy() {
@@ -81,11 +83,22 @@ bool VideoProxy::readData(void* data, size_t length, bool block) {
 }
 
 void VideoProxy::postEvent(enum mVideoLoggerEvent event) {
-	emit eventPosted(event);
+	if (QThread::currentThread() == thread()) {
+		// We're on the main thread
+		emit eventPosted(event);
+	} else {
+		m_mutex.lock();
+		emit eventPosted(event);
+		m_fromThreadCond.wait(&m_mutex, 1);
+		m_mutex.unlock();
+	}
 }
 
 void VideoProxy::handleEvent(int event) {
+	m_mutex.lock();
 	m_logger.d.handleEvent(&m_logger.d, static_cast<enum mVideoLoggerEvent>(event));
+	m_fromThreadCond.wakeAll();
+	m_mutex.unlock();
 }
 
 void VideoProxy::lock() {