comparison src/vamp-sdk/PluginAdapter.cpp @ 525:8c18bdaad04f c++11-mutex

Avoid simple static allocation of mutex, as it could lead to mutex being destroyed before last adapter that needs to use it (since adapters are usually also static)

                                      const Plugin::FeatureSet &features);
     
     // maps both plugins and descriptors to adapters
     typedef map<const void *, Impl *> AdapterMap;
     static AdapterMap *m_adapterMap;
-    static mutex m_adapterMapMutex;
+    static mutex *m_adapterMapMutex;
     static Impl *lookupAdapter(VampPluginHandle);
 
     mutex m_mutex; // guards all of the below
     
     bool m_populated;

     m_descriptor.releaseOutputDescriptor = vampReleaseOutputDescriptor;
     m_descriptor.process = vampProcess;
     m_descriptor.getRemainingFeatures = vampGetRemainingFeatures;
     m_descriptor.releaseFeatureSet = vampReleaseFeatureSet;
 
-    lock_guard<mutex> adapterMapGuard(m_adapterMapMutex);
+    lock_guard<mutex> adapterMapGuard(*m_adapterMapMutex);
     
     if (!m_adapterMap) {
         m_adapterMap = new AdapterMap;
     }
     (*m_adapterMap)[&m_descriptor] = this;

     for (unsigned int i = 0; i < m_descriptor.programCount; ++i) {
         free((void *)m_descriptor.programs[i]);
     }
     free((void *)m_descriptor.programs);
 
-    lock_guard<mutex> adapterMapGuard(m_adapterMapMutex);
+    lock_guard<mutex> adapterMapGuard(*m_adapterMapMutex);
     
     if (m_adapterMap) {
         
         m_adapterMap->erase(&m_descriptor);
-
+        
         if (m_adapterMap->empty()) {
             delete m_adapterMap;
             m_adapterMap = 0;
         }
     }

 {
 #ifdef DEBUG_PLUGIN_ADAPTER
     cerr << "PluginAdapterBase::Impl::lookupAdapter(" << handle << ")" << endl;
 #endif
 
-    lock_guard<mutex> adapterMapGuard(m_adapterMapMutex);
+    lock_guard<mutex> adapterMapGuard(*m_adapterMapMutex);
     
     if (!m_adapterMap) return 0;
     AdapterMap::const_iterator i = m_adapterMap->find(handle);
     if (i == m_adapterMap->end()) return 0;
     return i->second;

 {
 #ifdef DEBUG_PLUGIN_ADAPTER
     cerr << "PluginAdapterBase::Impl::vampInstantiate(" << desc << ")" << endl;
 #endif
 
-    lock_guard<mutex> adapterMapGuard(m_adapterMapMutex);
+    lock_guard<mutex> adapterMapGuard(*m_adapterMapMutex);
     
     if (!m_adapterMap) {
         m_adapterMap = new AdapterMap();
     }
 

 void 
 PluginAdapterBase::Impl::cleanup(Plugin *plugin)
 {
     // at this point no mutex is held
     
-    lock_guard<mutex> adapterMapGuard(m_adapterMapMutex);
+    lock_guard<mutex> adapterMapGuard(*m_adapterMapMutex);
     lock_guard<mutex> guard(m_mutex);
     
     if (m_fs.find(plugin) != m_fs.end()) {
         size_t outputCount = 0;
         if (m_pluginOutputs[plugin]) {

 }
   
 PluginAdapterBase::Impl::AdapterMap *
 PluginAdapterBase::Impl::m_adapterMap = 0;
 
-mutex
-PluginAdapterBase::Impl::m_adapterMapMutex;
+// This is allocated on the heap so that we can be sure it outlives
+// the adapters themselves, which are typically static within the
+// plugin library. If this was also static, then it might be destroyed
+// before the last adapter, and we would end up trying to lock an
+// invalid mutex when removing an adapter from the adapter map.
+mutex *
+PluginAdapterBase::Impl::m_adapterMapMutex = new mutex;
 
 }
 
 _VAMP_SDK_PLUGSPACE_END(PluginAdapter.cpp)