Ticket #9867: 0046-mheg-Use-a-shared-mutex-to-control-access-to-QWaitCo.patch

mythtv/libs/libmythtv/mhi.cpp

@@ -146 +146 @@
         while (!m_stopped)
         {
             m_stop = true;
-            m_engine_wait.wakeAll();
+            {QMutexLocker locker(&m_engineLock);
+            m_engine_wait.wakeAll();}
             usleep(1000);
         }
         pthread_join(m_engineThread, NULL);
@@ -234 +235 @@
 
 void MHIContext::RunMHEGEngine(void)
 {
-    // Qt4 requires a QMutex as a parameter...
-    // not sure if this is the best solution.  Mutex Must be locked before wait.
-    QMutex mutex;
-    mutex.lock();
-
     while (!m_stop)
     {
         int toWait;
@@ -268 +264 @@
         if (toWait > 1000 || toWait <= 0)
             toWait = 1000;
 
-        m_engine_wait.wait(&mutex, toWait);
+        QMutexLocker locker(&m_engineLock);
+        m_engine_wait.wait(&m_engineLock, toWait);
     }
 }
 
@@ -309 +306 @@
         return;
 
     memcpy(dataCopy, data, length*sizeof(unsigned char));
-    QMutexLocker locker(&m_dsmccLock);
+    {QMutexLocker locker(&m_dsmccLock);
     m_dsmccQueue.enqueue(new DSMCCPacket(dataCopy,     length,
                                          componentTag, carouselId,
-                                         dataBroadcastId));
+                                         dataBroadcastId));}
+    QMutexLocker locker(&m_engineLock);
     m_engine_wait.wakeAll();
 }
 
@@ -333 +331 @@
     if (m_lastNbiVersion == NBI_VERSION_UNSET)
         m_lastNbiVersion = data[0];
     else
+    {
+        QMutexLocker locker(&m_engineLock);
         m_engine_wait.wakeAll();
+    }
 }
 
 void MHIContext::NetworkBootRequested(void)
@@ -380 +381 @@
     // same thread this is safe.  Otherwise we need to make a deep copy of
     // the result.
 
-    // Qt4 requires a QMutex as a parameter...
-    // not sure if this is the best solution.  Mutex Must be locked before wait.
-    QMutex mutex;
-    mutex.lock();
-
     while (!m_stop)
     {
         int res = m_dsmcc->GetDSMCCObject(path, result);
@@ -397 +393 @@
         // some more packets.  We should eventually find out if this item is
         // present.
         ProcessDSMCCQueue();
-        m_engine_wait.wait(&mutex, 1000);
+        QMutexLocker locker(&m_engineLock);
+        m_engine_wait.wait(&m_engineLock, 1000);
     }
     return false; // Stop has been set.  Say the object isn't present.
 }
@@ -475 +472 @@
         m_keyQueue.enqueue(action);
         VERBOSE(VB_IMPORTANT, "Adding MHEG key "<<key<<":"<<action
                 <<":"<<m_keyQueue.size());
+        locker.unlock();
+        QMutexLocker locker2(&m_engineLock);
         m_engine_wait.wakeAll();
         return true;
     }

mythtv/libs/libmythtv/mhi.h

@@ -159 +159 @@
     MHEG            *m_engine; // Pointer to the MHEG engine
 
     QWaitCondition   m_engine_wait;
+    QMutex           m_engineLock;
     bool             m_stop;
     bool             m_stopped;
     QMutex           m_display_lock;