# HG changeset patch
# User Chris Cannam
# Date 1568021053 -3600
# Node ID 8c18bdaad04f69d4bb2a39c250b3e127551502ce
# Parent  762b79b49c312300fb0a7b3c778f8650ea042e3f
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)

diff -r 762b79b49c31 -r 8c18bdaad04f src/vamp-sdk/PluginAdapter.cpp
--- a/src/vamp-sdk/PluginAdapter.cpp	Mon Sep 09 10:23:37 2019 +0100
+++ b/src/vamp-sdk/PluginAdapter.cpp	Mon Sep 09 10:24:13 2019 +0100
@@ -124,7 +124,7 @@
     // 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
@@ -275,7 +275,7 @@
     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;
@@ -325,12 +325,12 @@
     }
     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;
@@ -345,7 +345,7 @@
     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);
@@ -361,7 +361,7 @@
     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();
@@ -625,7 +625,7 @@
 {
     // 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()) {
@@ -990,8 +990,13 @@
 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;
 
 }