From ec1ce1d7388bdf3fe5f69b253100d2110e97ab86 Mon Sep 17 00:00:00 2001
From: baldurk <baldurk@baldurk.org>
Date: Wed, 12 Oct 2016 13:01:09 +0200
Subject: [PATCH] Fix bool checks across threads to be correct, so it's not
 optimised out

---
 qrenderdoc/Code/CaptureContext.h  |  5 ++++-
 qrenderdoc/Code/RenderManager.cpp | 12 ++++++++----
 qrenderdoc/Code/RenderManager.h   |  6 +++---
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/qrenderdoc/Code/CaptureContext.h b/qrenderdoc/Code/CaptureContext.h
index b519e74b3..14c7a3d94 100644
--- a/qrenderdoc/Code/CaptureContext.h
+++ b/qrenderdoc/Code/CaptureContext.h
@@ -238,6 +238,7 @@ private:
 
   std::function<void()> m_func;
   QThread *m_Thread;
+  QSemaphore completed;
 
 public slots:
   void process()
@@ -246,11 +247,13 @@ public slots:
     m_Thread->quit();
     m_Thread->deleteLater();
     m_Thread = NULL;
+    completed.acquire();
   }
 
 public:
   explicit LambdaThread(std::function<void()> f)
   {
+    completed.release();
     m_Thread = new QThread();
     m_func = f;
     moveToThread(m_Thread);
@@ -258,7 +261,7 @@ public:
   }
 
   void start(QThread::Priority prio = QThread::InheritPriority) { m_Thread->start(prio); }
-  bool isRunning() { return m_Thread; }
+  bool isRunning() { return completed.available(); }
 };
 
 class QMenu;
diff --git a/qrenderdoc/Code/RenderManager.cpp b/qrenderdoc/Code/RenderManager.cpp
index 85cc2dcd1..45d7f62b0 100644
--- a/qrenderdoc/Code/RenderManager.cpp
+++ b/qrenderdoc/Code/RenderManager.cpp
@@ -75,9 +75,13 @@ void RenderManager::BlockInvoke(RenderManager::InvokeMethod m)
 
   PushInvoke(cmd);
 
-  while(!cmd->processed)
+  for(;;)
   {
+    if(cmd->processed.tryAcquire())
+      break;
   }
+
+  delete cmd;
 }
 
 void RenderManager::CloseThread()
@@ -102,7 +106,7 @@ void RenderManager::PushInvoke(RenderManager::InvokeHandle *cmd)
 {
   if(m_Thread == NULL || !m_Thread->isRunning() || !m_Running)
   {
-    cmd->processed = true;
+    cmd->processed.release();
     if(cmd->selfdelete)
       delete cmd;
     return;
@@ -150,7 +154,7 @@ void RenderManager::run()
       if(cmd->method != NULL)
         cmd->method(renderer);
 
-      cmd->processed = true;
+      cmd->processed.release();
 
       // if it's a throwaway command, delete it
       if(cmd->selfdelete)
@@ -171,7 +175,7 @@ void RenderManager::run()
       if(cmd == NULL)
         continue;
 
-      cmd->processed = true;
+      cmd->processed.release();
 
       if(cmd->selfdelete)
         delete cmd;
diff --git a/qrenderdoc/Code/RenderManager.h b/qrenderdoc/Code/RenderManager.h
index 5a5314a29..7aa3a0ad9 100644
--- a/qrenderdoc/Code/RenderManager.h
+++ b/qrenderdoc/Code/RenderManager.h
@@ -26,6 +26,7 @@
 
 #include <QMutex>
 #include <QQueue>
+#include <QSemaphore>
 #include <QString>
 #include <QThread>
 #include <QWaitCondition>
@@ -62,12 +63,11 @@ private:
     InvokeHandle(InvokeMethod m)
     {
       method = m;
-      processed = false;
-      selfdelete = true;
+      selfdelete = false;
     }
 
     InvokeMethod method;
-    bool processed;
+    QSemaphore processed;
     bool selfdelete;
   };